# kb

id: isentropic-process-20260505-0
file: data/en.wikipedia.org/wiki/Isentropic_process-0.md
category: reference
title: Isentropic process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isentropic_process
date_saved: 2026-05-05T10:57:13.245109+00:00
instance: kb-cron
parent: isentropic-process-20260505-0
summary:
An isentropic process is an idealized thermodynamic process that is both adiabatic and reversible. In thermodynamics, adiabatic processes are reversible. Clausius (1875) adopted "isentropic" as meaning the same as Rankine's word: "adiabatic". The work transfers of the system are frictionless, and there is no net transfer of heat or matter. Such an idealized process is useful in engineering as a model of and basis of comparison for real processes. This process is idealized because reversible processes do not occur in reality; thinking of a process as both adiabatic and reversible would show that the initial and final entropies are the same, thus, the reason it is called isentropic (entropy does not change). Thermodynamic processes are named based on the effect they would have on the system (ex. isovolumetric/isochoric: constant volume, isenthalpic: constant enthalpy). Even though in reality it is not necessarily possible to carry out an isentropic process, some may be approximated as such. The word "isentropic" derives from the process being one in which the entropy of the system remains unchanged, in addition to a process which is both adiabatic and reversible. == Background == The second law of thermodynamics states that T surr d S ≥ δ Q


id: isentropic-process-20260505-1
file: data/en.wikipedia.org/wiki/Isentropic_process-1.md
category: reference
title: Isentropic process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isentropic_process
date_saved: 2026-05-05T10:57:13.245109+00:00
instance: kb-cron
parent: isentropic-process-20260505-0
summary:
Then for a process that is both reversible and adiabatic (i.e. no heat transfer occurs), δ Q rev = 0 {\displaystyle \delta Q_{\text{rev}}=0} , and so d S = δ Q rev / T = 0 {\displaystyle dS=\delta Q_{\text{rev}}/T=0} All reversible adiabatic processes are isentropic. This leads to two important observations: d U = δ W + δ Q = − p d V + 0 , {\displaystyle dU=\delta W+\delta Q=-p\,dV+0,} d H = δ W + δ Q + p d V + V d p = − p d V + 0 + p d V + V d p = V d p . {\displaystyle dH=\delta W+\delta Q+p\,dV+V\,dp=-p\,dV+0+p\,dV+V\,dp=V\,dp.} Next, a great deal can be computed for isentropic processes of an ideal gas. For any transformation of an ideal gas, it is always true that d U = n C v d T {\displaystyle dU=nC_{v}\,dT} , and d H = n C p d T . {\displaystyle dH=nC_{p}\,dT.} Using the general results derived above for d U {\displaystyle dU} and d H {\displaystyle dH} , then d U = n C v d T = − p d V , {\displaystyle dU=nC_{v}\,dT=-p\,dV,} d H = n C p


id: isobaric-process-20260505-0
file: data/en.wikipedia.org/wiki/Isobaric_process-0.md
category: reference
title: Isobaric process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isobaric_process
date_saved: 2026-05-05T10:57:14.483031+00:00
instance: kb-cron
parent: isobaric-process-20260505-0
summary:
In thermodynamics, an isobaric process is a type of thermodynamic process in which the pressure of the system stays constant: ΔP = 0. The heat transferred to the system does work, but also changes the internal energy (U) of the system. This article uses the physics sign convention for work, where positive work is work done by the system. Using this convention, by the first law of thermodynamics, Q = Δ U + W {\displaystyle Q=\Delta U+W\,} where W is work, U is internal energy, and Q is heat. Pressure-volume work by the closed system is defined as: W = ∫ p d V {\displaystyle W=\int \!p\,dV\,} where Δ means change over the whole process, whereas d denotes a differential. Since pressure is constant, this means that W = p Δ V {\displaystyle W=p\Delta V\,} . Applying the ideal gas law, this becomes W = n R Δ T {\displaystyle W=n\,R\,\Delta T} with R representing the gas constant, and n representing the amount of substance, which is assumed to remain constant (e.g., there is no phase transition during a chemical reaction). According to the equipartition theorem, the change in internal energy is related to the temperature of the system by


id: isobaric-process-20260505-1
file: data/en.wikipedia.org/wiki/Isobaric_process-1.md
category: reference
title: Isobaric process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isobaric_process
date_saved: 2026-05-05T10:57:14.483031+00:00
instance: kb-cron
parent: isobaric-process-20260505-0
summary:
In the first process example, a cylindrical chamber 1 m2 in area encloses 81.2438 mol of an ideal diatomic gas of molecular mass 29 g mol−1 at 300 K. The surrounding gas is at 1 atm and 300 K, and separated from the cylinder gas by a thin piston. For the limiting case of a massless piston, the cylinder gas is also at 1 atm pressure, with an initial volume of 2 m3. Heat is added slowly until the gas temperature is uniformly 600 K, after which the gas volume is 4 m3 and the piston is 2 m above its initial position. If the piston motion is sufficiently slow, the gas pressure at each instant will have practically the same value (psys = 1 atm) throughout. For a thermally perfect diatomic gas, the molar specific heat capacity at constant pressure (cp) is 7/2R or 29.1006 J mol−1 deg−1. The molar heat capacity at constant volume (cv) is 5/2R or 20.7862 J mol−1 deg−1. The ratio γ {\displaystyle \gamma } of the two heat capacities is 1.4. The heat Q required to bring the gas from 300 to 600 K is Q = Δ H = n c p Δ


id: isochoric-process-20260505-0
file: data/en.wikipedia.org/wiki/Isochoric_process-0.md
category: reference
title: Isochoric process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isochoric_process
date_saved: 2026-05-05T10:57:15.681952+00:00
instance: kb-cron
parent: isochoric-process-20260505-0
summary:
In thermodynamics, an isochoric process, also called a constant-volume process, an isovolumetric process, or an isometric process, is a thermodynamic process during which the volume of the closed system undergoing such a process remains constant. An isochoric process is exemplified by the heating or the cooling of the contents of a sealed, inelastic container: The thermodynamic process is the addition or removal of heat; the isolation of the contents of the container establishes the closed system; and the inability of the container to deform imposes the constant-volume condition. == Formalism == An isochoric thermodynamic quasi-static process is characterized by constant volume, i.e., ΔV = 0. The process does no pressure-volume work, since such work is defined by W = P Δ V , {\displaystyle W=P\Delta V,} where P is pressure. The sign convention is such that positive work is performed by the system on the environment. If the process is not quasi-static, the work can perhaps be done in a volume constant thermodynamic process. For a reversible process, the first law of thermodynamics gives the change in the system's internal energy: d U = d Q − d W {\displaystyle dU=dQ-dW} Replacing work with a change in volume gives d


id: isothermal-process-20260505-0
file: data/en.wikipedia.org/wiki/Isothermal_process-0.md
category: reference
title: Isothermal process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isothermal_process
date_saved: 2026-05-05T10:57:16.881965+00:00
instance: kb-cron
parent: isothermal-process-20260505-0
summary:
An isothermal process is a type of thermodynamic process in which the temperature T of a system remains constant: ΔT = 0. This typically occurs when a system is in contact with an outside thermal reservoir, and a change in the system occurs slowly enough to allow the system to be continuously adjusted to the temperature of the reservoir through heat exchange (see quasi-equilibrium). In contrast, an adiabatic process is where a system exchanges no heat with its surroundings (Q = 0). Simply, we can say that in an isothermal process T = constant {\displaystyle T={\text{constant}}} Δ T = 0 {\displaystyle \Delta T=0} d T = 0 {\displaystyle dT=0} For ideal gases only, internal energy Δ U = 0 {\displaystyle \Delta U=0} while in adiabatic processes: Q = 0. {\displaystyle Q=0.} == Etymology == The noun isotherm is derived from the Ancient Greek words ἴσος (ísos), meaning "equal", and θέρμη (thérmē), meaning "heat". == Examples == Isothermal processes can occur in any kind of system that has some means of regulating the temperature, including highly structured machines, and even living cells. Some parts of the cycles of some heat engines are carried out isothermally (for example, in the Carnot cycle).


id: isothermal-process-20260505-1
file: data/en.wikipedia.org/wiki/Isothermal_process-1.md
category: reference
title: Isothermal process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isothermal_process
date_saved: 2026-05-05T10:57:16.881965+00:00
instance: kb-cron
parent: isothermal-process-20260505-0
summary:
In IUPAC convention, work is defined as work on a system by its surroundings. If, for example, the system is compressed, then the work is done on the system by the surrounding so the work is positive and the internal energy of the system increases. Conversely, if the system expands (i.e., system surrounding expansion, so free expansions not the case), then the work is negative as the system does work on the surroundings. It is also worth noting that for ideal gases, if the temperature is held constant, the internal energy of the system U also is constant, and so ΔU = 0. Since the first law of thermodynamics states that ΔU = Q + W in IUPAC convention, it follows that Q = −W for the isothermal compression or expansion of ideal gases. == Example of an isothermal process == The reversible expansion of an ideal gas can be used as an example of work produced by an isothermal process. Of particular interest is the extent to which heat is converted to usable work, and the relationship between the confining force and the extent of expansion. During isothermal expansion of an ideal gas, both p and V change along


id: isothermal-process-20260505-2
file: data/en.wikipedia.org/wiki/Isothermal_process-2.md
category: reference
title: Isothermal process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Isothermal_process
date_saved: 2026-05-05T10:57:16.881965+00:00
instance: kb-cron
parent: isothermal-process-20260505-0
summary:
Δ S = n R ln ⁡ P A P B {\displaystyle \Delta S=nR\ln {\frac {P_{\text{A}}}{P_{\text{B}}}}} . Once obtained, these formulas can be applied to an irreversible process, such as the free expansion of an ideal gas. Such an expansion is also isothermal and may have the same initial and final states as in the reversible expansion. Since entropy is a state function (that depends on an equilibrium state, not depending on a path that the system takes to reach that state), the change in entropy of the system is the same as in the reversible process and is given by the formulas above. Note that the result Q = 0 for the free expansion can not be used in the formula for the entropy change since the process is not reversible. The difference between the reversible and irreversible is found in the entropy of the surroundings. In both cases, the surroundings are at a constant temperature, T, so that ΔSsur = −⁠Q/T⁠; the minus sign is used since the heat transferred to the surroundings is equal in magnitude and opposite in sign to the heat Q transferred to the system. In the reversible case, the change in entropy of


id: mass-injection-flow-20260505-0
file: data/en.wikipedia.org/wiki/Mass_injection_flow-0.md
category: reference
title: Mass injection flow
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mass_injection_flow
date_saved: 2026-05-05T10:57:18.086943+00:00
instance: kb-cron
parent: mass-injection-flow-20260505-0
summary:
Mass injection flow (a.k.a. Limbach Flow) refers to inviscid, adiabatic flow through a constant area duct where the effect of mass addition is considered. For this model, the duct area remains constant, the flow is assumed to be steady and one-dimensional, and mass is added within the duct. Because the flow is adiabatic, unlike in Rayleigh flow, the stagnation temperature is a constant. Compressibility effects often come into consideration, though this flow model also applies to incompressible flow. For supersonic flow (an upstream Mach number greater than 1), deceleration occurs with mass addition to the duct and the flow can become choked. Conversely, for subsonic flow (an upstream Mach number less than 1), acceleration occurs and the flow can become choked given sufficient mass addition. Therefore, mass addition will cause both supersonic and subsonic Mach numbers to approach Mach 1, resulting in choked flow. == Theory == The 1D mass injection flow model begins with a mass-velocity relation derived for mass injection into a steady, adiabatic, frictionless, constant area flow of calorically perfect gas: d m m = − d u u ( M 2 − 1 ) {\displaystyle \ {\frac {dm}{m}}=-{\frac {du}{u}}\left(M^{2}-1\right)} where m {\displaystyle m} represents a mass


id: polytropic-process-20260505-0
file: data/en.wikipedia.org/wiki/Polytropic_process-0.md
category: reference
title: Polytropic process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Polytropic_process
date_saved: 2026-05-05T10:57:19.316858+00:00
instance: kb-cron
parent: polytropic-process-20260505-0
summary:
A polytropic process is a thermodynamic process that obeys the relation: p V n = C {\displaystyle pV^{n}=C} where p is the pressure, V is volume, n is the polytropic index, and C is a constant. The polytropic process equation describes expansion and compression processes which include heat transfer. == Particular cases == Some specific values of n correspond to particular cases: n = 0 {\displaystyle n=0} for an isobaric process, n = + ∞ {\displaystyle n=+\infty } for an isochoric process. In addition, when the ideal gas law applies: n = 1 {\displaystyle n=1} for an isothermal process, n = γ {\displaystyle n=\gamma } for an isentropic process. Where γ {\displaystyle \gamma } is the ratio of the heat capacity at constant pressure ( C P {\displaystyle C_{P}} ) to heat capacity at constant volume ( C V {\displaystyle C_{V}} ). == Equivalence between the polytropic coefficient and the ratio of energy transfers == For an ideal gas in a closed system undergoing a slow process with negligible changes in kinetic and potential energy the process is polytropic, such that p v ( 1 − γ ) K + γ = C {\displaystyle pv^{(1-\gamma )K+\gamma }=C} where C is


id: quasistatic-process-20260505-0
file: data/en.wikipedia.org/wiki/Quasistatic_process-0.md
category: reference
title: Quasistatic process
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Quasistatic_process
date_saved: 2026-05-05T10:57:20.519703+00:00
instance: kb-cron
parent: quasistatic-process-20260505-0
summary:
In thermodynamics, a quasi-static process, also known as a quasi-equilibrium process (from Latin quasi, meaning ‘as if’), is a thermodynamic process that happens slowly enough for the system to remain in internal physical (but not necessarily chemical) thermodynamic equilibrium. An example of this is quasi-static expansion of a mixture of hydrogen and oxygen gas, where the volume of the system changes so slowly that the pressure remains uniform throughout the system at each instant of time during the process. Such an idealized process is a succession of physical equilibrium states, characterized by infinite slowness. Only in a quasi-static thermodynamic process can we exactly define intensive quantities (such as pressure, temperature, specific volume, specific entropy) of the system at any instant during the whole process; otherwise, since no internal equilibrium is established, different parts of the system would have different values of these quantities, so a single value per quantity may not be sufficient to represent the whole system. In other words, when an equation for a change in a state function contains P or T, it implies a quasi-static process. == Relation to reversible process == While all reversible processes are quasi-static, most authors do not require a general quasi-static


id: reversible-process-thermodynamics-20260505-0
file: data/en.wikipedia.org/wiki/Reversible_process_(thermodynamics)-0.md
category: reference
title: Reversible process (thermodynamics)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reversible_process_(thermodynamics)
date_saved: 2026-05-05T10:57:21.720507+00:00
instance: kb-cron
parent: reversible-process-thermodynamics-20260505-0
summary:
In thermodynamics, a reversible process is a process, involving a system and its surroundings, whose direction can be reversed by infinitesimal changes in some properties of the surroundings, such as pressure or temperature. Throughout an entire reversible process, the system is in thermodynamic equilibrium, both physical and chemical, and nearly in pressure and temperature equilibrium with its surroundings. This prevents unbalanced forces and acceleration of moving system boundaries, which in turn avoids friction and other dissipation. To maintain equilibrium, reversible processes are extremely slow (quasistatic). The process must occur slowly enough that after some small change in a thermodynamic parameter, the physical processes in the system have enough time for the other parameters to self-adjust to match the new, changed parameter value. For example, if a container of water has sat in a room long enough to match the steady temperature of the surrounding air, for a small change in the air temperature to be reversible, the whole system of air, water, and container must wait long enough for the container and air to settle into a new, matching temperature before the next small change can occur. While processes in isolated systems are never reversible, cyclical processes can be reversible


id: supercooling-20260505-0
file: data/en.wikipedia.org/wiki/Supercooling-0.md
category: reference
title: Supercooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Supercooling
date_saved: 2026-05-05T10:57:22.942902+00:00
instance: kb-cron
parent: supercooling-20260505-0
summary:
Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid below its freezing point without it becoming a solid. Per the established international definition, supercooling means "cooling a substance below the normal freezing point without solidification". While it can be achieved by different physical means, the postponed solidification is most often due to the absence of seed crystals or nuclei around which a crystal structure can form. The supercooling of water can be achieved without any special techniques other than chemical demineralization, down to −48.3 °C (−54.9 °F). Supercooled water can occur naturally, for example in the atmosphere, animals or plants. This phenomenon was first described in 1724 by Daniel Gabriel Fahrenheit, while developing the Fahrenheit scale. == Explanation == A liquid crossing its standard freezing point will crystallize in the presence of a seed crystal or nucleus around which a crystal structure can form creating a solid. Lacking any such nuclei, the liquid phase can be maintained all the way down to the temperature at which crystal homogeneous nucleation occurs. Homogeneous nucleation can occur above the glass transition temperature, but if homogeneous nucleation has not occurred above that temperature, an amorphous (non-crystalline) solid will


id: supercooling-20260505-1
file: data/en.wikipedia.org/wiki/Supercooling-1.md
category: reference
title: Supercooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Supercooling
date_saved: 2026-05-05T10:57:22.942902+00:00
instance: kb-cron
parent: supercooling-20260505-0
summary:
== In animals == In order to survive extreme low temperatures in certain environments, some animals use the phenomenon of supercooling that allow them to remain unfrozen and avoid cell damage and death. There are many techniques that aid in maintaining a liquid state, such as the production of antifreeze proteins, or AFPs, which bind to ice crystals to prevent water molecules from binding and spreading the growth of ice. The winter flounder is one such fish that utilizes these proteins to survive in its frigid environment. The liver secretes noncolligative proteins into the bloodstream. Other animals use colligative antifreezes, which increase the concentration of solutes in their bodily fluids, thus lowering their freezing point. Fish that rely on supercooling for survival must also live well below the water surface, because if they came into contact with ice nuclei they would freeze immediately. Animals that undergo supercooling to survive must also remove ice-nucleating agents from their bodies because they act as a starting point for freezing. Supercooling is also a common feature in some insect, reptile, and other ectotherm species. The potato cyst nematode larva (Globodera rostochiensis) could survive inside their cysts in a supercooled state to temperatures as low


id: supercooling-20260505-2
file: data/en.wikipedia.org/wiki/Supercooling-2.md
category: reference
title: Supercooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Supercooling
date_saved: 2026-05-05T10:57:22.942902+00:00
instance: kb-cron
parent: supercooling-20260505-0
summary:
== Applications == One commercial application of supercooling is in refrigeration. Freezers can cool drinks to a supercooled level so that when they are opened, they form a slush. Another example is a product that can supercool the beverage in a conventional freezer. The Coca-Cola Company briefly marketed special vending machines containing Sprite in the UK, and Coke in Singapore, which stored the bottles in a supercooled state so that their content would turn to slush upon opening. Supercooling was successfully applied to organ preservation at Massachusetts General Hospital/Harvard Medical School. Livers that were later transplanted into recipient animals were preserved by supercooling for up to 4 days, quadrupling the limits of what could be achieved by conventional liver preservation methods. The livers were supercooled to a temperature of −6 °C (21 °F) in a specialized solution that protected against freezing and injury from the cold temperature. Another potential application is drug delivery. In 2015, researchers crystallized membranes at a specific time. Liquid-encapsulated drugs could be delivered to the site and, with a slight environmental change, the liquid rapidly changes into a crystalline form that releases the drug. In 2016, a team at Iowa State University proposed a method for


id: superheating-20260505-0
file: data/en.wikipedia.org/wiki/Superheating-0.md
category: reference
title: Superheating
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Superheating
date_saved: 2026-05-05T10:57:24.142400+00:00
instance: kb-cron
parent: superheating-20260505-0
summary:
In thermodynamics, superheating (sometimes referred to as boiling retardation, or boiling delay) is the phenomenon in which a liquid is heated to a temperature higher than its boiling point, without boiling. This is a so-called metastable state or metastate, where boiling might occur at any time, induced by external or internal effects. Superheating is achieved by heating a homogeneous substance in a clean container, free of nucleation sites, while taking care not to disturb the liquid. This may occur by microwaving water in a very smooth container. Disturbing the water may cause an unsafe eruption of hot water and result in burns. == Cause == Water is said to "boil" when bubbles of water vapor grow without bound, bursting at the surface. For a vapor bubble to expand, the temperature must be high enough that the vapor pressure exceeds the ambient pressure (the atmospheric pressure, primarily). Below that temperature, a water vapor bubble will shrink and vanish. Superheating is an exception to this simple rule; a liquid is sometimes observed not to boil even though its vapor pressure does exceed the ambient pressure. The cause is an additional force, the surface tension, which suppresses the growth of bubbles. Surface tension


id: thermodynamic-cycle-20260505-0
file: data/en.wikipedia.org/wiki/Thermodynamic_cycle-0.md
category: reference
title: Thermodynamic cycle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_cycle
date_saved: 2026-05-05T10:57:25.331304+00:00
instance: kb-cron
parent: thermodynamic-cycle-20260505-0
summary:
A thermodynamic cycle consists of linked sequences of thermodynamic processes that involve transfer of heat and work into and out of the system, while varying pressure, temperature, and other state variables within the system, and that eventually returns the system to its initial state. In the process of passing through a cycle, the working fluid (system) may convert heat from a warm source into useful work, and dispose of the remaining heat to a cold sink, thereby acting as a heat engine. Conversely, the cycle may be reversed and use work to move heat from a cold source and transfer it to a warm sink thereby acting as a heat pump. If at every point in the cycle the system is in thermodynamic equilibrium, the cycle is reversible. Whether carried out reversibly or irreversibly, the net entropy change of the system is zero, as entropy is a state function. During a closed cycle, the system returns to its original thermodynamic state of temperature and pressure. Process quantities (or path quantities), such as heat and work are process dependent. For a cycle for which the system returns to its initial state the first law of thermodynamics applies: Δ U = E


id: thermodynamic-cycle-20260505-1
file: data/en.wikipedia.org/wiki/Thermodynamic_cycle-1.md
category: reference
title: Thermodynamic cycle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_cycle
date_saved: 2026-05-05T10:57:25.331304+00:00
instance: kb-cron
parent: thermodynamic-cycle-20260505-0
summary:
1→2: Isentropic / adiabatic expansion: Constant entropy (s), Decrease in pressure (P), Increase in volume (v), Decrease in temperature (T) 2→3: Isochoric cooling: Constant volume(v), Decrease in pressure (P), Decrease in entropy (S), Decrease in temperature (T) 3→4: Isentropic / adiabatic compression: Constant entropy (s), Increase in pressure (P), Decrease in volume (v), Increase in temperature (T) 4→1: Isochoric heating: Constant volume (v), Increase in pressure (P), Increase in entropy (S), Increase in temperature (T) === Power cycles === Thermodynamic power cycles are the basis for the operation of heat engines, which supply most of the world's electric power and run the vast majority of motor vehicles. Power cycles can be organized into two categories: real cycles and ideal cycles. Cycles encountered in real world devices (real cycles) are difficult to analyze because of the presence of complicating effects (friction), and the absence of sufficient time for the establishment of equilibrium conditions. For the purpose of analysis and design, idealized models (ideal cycles) are created; these ideal models allow engineers to study the effects of major parameters that dominate the cycle without having to spend significant time working out intricate details present in the real cycle model. Power cycles can


id: thermodynamic-cycle-20260505-2
file: data/en.wikipedia.org/wiki/Thermodynamic_cycle-2.md
category: reference
title: Thermodynamic cycle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_cycle
date_saved: 2026-05-05T10:57:25.331304+00:00
instance: kb-cron
parent: thermodynamic-cycle-20260505-0
summary:
TOP (A) and BOTTOM (C) of the loop: a pair of parallel isobaric processes RIGHT (B) and LEFT (D) of the loop: a pair of parallel isochoric processes If the working substance is a perfect gas, U {\displaystyle U} is only a function of T {\displaystyle T} for a closed system since its internal pressure vanishes. Therefore, the internal energy changes of a perfect gas undergoing various processes connecting initial state a {\displaystyle a} to final state b {\displaystyle b} are always given by the formula Δ U = ∫ a b C v d T {\displaystyle \Delta U=\int _{a}^{b}C_{v}dT} Assuming that C v {\displaystyle C_{v}} is constant, Δ U = C v Δ T {\displaystyle \Delta U=C_{v}\Delta T} for any process undergone by a perfect gas. Under this set of assumptions, for processes A and C we have W = p Δ v {\displaystyle W=p\Delta v} and Q = C p Δ T {\displaystyle Q=C_{p}\Delta T} , whereas for processes B and D we have W = 0 {\displaystyle W=0} and Q = Δ U = C v Δ T {\displaystyle Q=\Delta U=C_{v}\Delta T} . The total work done per cycle is W c y c l e =


id: thermodynamic-efficiency-limit-20260505-0
file: data/en.wikipedia.org/wiki/Thermodynamic_efficiency_limit-0.md
category: reference
title: Thermodynamic efficiency limit
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_efficiency_limit
date_saved: 2026-05-05T10:57:26.518623+00:00
instance: kb-cron
parent: thermodynamic-efficiency-limit-20260505-0
summary:
The thermodynamic efficiency limit is the absolute maximum theoretically possible conversion efficiency of sunlight to electricity. Its value is about 86%, which is the Chambadal-Novikov efficiency, an approximation related to the Carnot limit, based on the temperature of the photons emitted by the Sun's surface. == Effect of band gap energy == Solar cells operate as quantum energy conversion devices, and are therefore subject to the thermodynamic efficiency limit. Photons with an energy below the band gap of the absorber material cannot generate an electron-hole pair, and so their energy is not converted to useful output and only generates heat if absorbed. For photons with an energy above the band gap energy, only a fraction of the energy above the band gap can be converted to useful output. When a photon of greater energy is absorbed, the excess energy above the band gap is converted to kinetic energy of the carrier recombination. The excess kinetic energy is converted to heat through phonon interactions as the kinetic energy of the carriers slows to equilibrium velocity. Hence, the solar energy cannot be converted to electricity beyond a certain limit. Solar cells with multiple band gap absorber materials improve efficiency by dividing the


id: thermodynamic-equilibrium-20260505-0
file: data/en.wikipedia.org/wiki/Thermodynamic_equilibrium-0.md
category: reference
title: Thermodynamic equilibrium
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_equilibrium
date_saved: 2026-05-05T10:57:27.731222+00:00
instance: kb-cron
parent: thermodynamic-equilibrium-20260505-0
summary:
Thermodynamic equilibrium is a notion of thermodynamics with axiomatic status referring to an internal state of a single thermodynamic system, or a relation between several thermodynamic systems connected by more or less permeable or impermeable walls. In thermodynamic equilibrium, there are no net macroscopic flows of mass nor of energy within a system or between systems. In a system that is in its own state of internal thermodynamic equilibrium, not only is there an absence of macroscopic change, but there is an "absence of any tendency toward change on a macroscopic scale." Systems in mutual thermodynamic equilibrium are simultaneously in mutual thermal, mechanical, chemical, and radiative equilibria. Systems can be in one kind of mutual equilibrium, while not in others. In thermodynamic equilibrium, all kinds of equilibrium hold at once and indefinitely, unless disturbed by a thermodynamic operation. In a macroscopic equilibrium, perfectly or almost perfectly balanced microscopic exchanges occur; this is the physical explanation of the notion of macroscopic equilibrium. A thermodynamic system in a state of internal thermodynamic equilibrium has a spatially uniform temperature. Its intensive properties, other than temperature, may be driven to spatial inhomogeneity by an unchanging long-range force field imposed on it by its surroundings.


id: thermodynamic-equilibrium-20260505-1
file: data/en.wikipedia.org/wiki/Thermodynamic_equilibrium-1.md
category: reference
title: Thermodynamic equilibrium
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_equilibrium
date_saved: 2026-05-05T10:57:27.731222+00:00
instance: kb-cron
parent: thermodynamic-equilibrium-20260505-0
summary:
== Relation of exchange equilibrium between systems == Often the surroundings of a thermodynamic system may also be regarded as another thermodynamic system. In this view, one may consider the system and its surroundings as two systems in mutual contact, with long-range forces also linking them. The enclosure of the system is the surface of contiguity or boundary between the two systems. In the thermodynamic formalism, that surface is regarded as having specific properties of permeability. For example, the surface of contiguity may be supposed to be permeable only to heat, allowing energy to transfer only as heat. Then the two systems are said to be in thermal equilibrium when the long-range forces are unchanging in time and the transfer of energy as heat between them has slowed and eventually stopped permanently; this is an example of a contact equilibrium. Other kinds of contact equilibrium are defined by other kinds of specific permeability. When two systems are in contact equilibrium with respect to a particular kind of permeability, they have common values of the intensive variable that belongs to that particular kind of permeability. Examples of such intensive variables are temperature, pressure, chemical potential. A contact equilibrium may be regarded


id: thermodynamic-equilibrium-20260505-2
file: data/en.wikipedia.org/wiki/Thermodynamic_equilibrium-2.md
category: reference
title: Thermodynamic equilibrium
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_equilibrium
date_saved: 2026-05-05T10:57:27.731222+00:00
instance: kb-cron
parent: thermodynamic-equilibrium-20260505-0
summary:
== Multiple contact equilibrium == The thermodynamic formalism allows that a system may have contact with several other systems at once, which may or may not also have mutual contact, the contacts having respectively different permeabilities. If these systems are all jointly isolated from the rest of the world those of them that are in contact then reach respective contact equilibria with one another. If several systems are free of adiabatic walls between each other, but are jointly isolated from the rest of the world, then they reach a state of multiple contact equilibrium, and they have a common temperature, a total internal energy, and a total entropy. Amongst intensive variables, this is a unique property of temperature. It holds even in the presence of long-range forces. (That is, there is no "force" that can maintain temperature discrepancies.) For example, in a system in thermodynamic equilibrium in a vertical gravitational field, the pressure on the top wall is less than that on the bottom wall, but the temperature is the same everywhere. A thermodynamic operation may occur as an event restricted to the walls that are within the surroundings, directly affecting neither the walls of contact of the system of


id: thermodynamic-equilibrium-20260505-3
file: data/en.wikipedia.org/wiki/Thermodynamic_equilibrium-3.md
category: reference
title: Thermodynamic equilibrium
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_equilibrium
date_saved: 2026-05-05T10:57:27.731222+00:00
instance: kb-cron
parent: thermodynamic-equilibrium-20260505-0
summary:
== Local and global equilibrium == It can be useful to distinguish between global and local thermodynamic equilibrium. In thermodynamics, exchanges within a system and between the system and the outside are controlled by intensive parameters. As an example, temperature controls heat exchanges. Global thermodynamic equilibrium (GTE) means that those intensive parameters are homogeneous throughout the whole system, while local thermodynamic equilibrium (LTE) means that those intensive parameters are varying in space and time, but are varying so slowly that, for any point, one can assume thermodynamic equilibrium in some neighborhood about that point. If the description of the system requires variations in the intensive parameters that are too large, the very assumptions upon which the definitions of these intensive parameters are based will break down, and the system will be in neither global nor local equilibrium. For example, it takes a certain number of collisions for a particle to equilibrate to its surroundings. If the average distance it has moved during these collisions removes it from the neighborhood it is equilibrating to, it will never equilibrate, and there will be no LTE. Temperature is, by definition, proportional to the average internal energy of an equilibrated neighborhood. Since there is


id: thermodynamic-equilibrium-20260505-4
file: data/en.wikipedia.org/wiki/Thermodynamic_equilibrium-4.md
category: reference
title: Thermodynamic equilibrium
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_equilibrium
date_saved: 2026-05-05T10:57:27.731222+00:00
instance: kb-cron
parent: thermodynamic-equilibrium-20260505-0
summary:
== Definitions == The most general kind of thermodynamic equilibrium of a system is through contact with the surroundings that allows simultaneous passages of all chemical substances and all kinds of energy. A system in thermodynamic equilibrium may move with uniform acceleration through space but must not change its shape or size while doing so; thus it is defined by a rigid volume in space. It may lie within external fields of force, determined by external factors of far greater extent than the system itself, so that events within the system cannot in an appreciable amount affect the external fields of force. The system can be in thermodynamic equilibrium only if the external force fields are uniform, and are determining its uniform acceleration, or if it lies in a non-uniform force field but is held stationary there by local forces, such as mechanical pressures, on its surface. Thermodynamic equilibrium is a primitive notion of the theory of thermodynamics. According to P.M. Morse: "It should be emphasized that the fact that there are thermodynamic states, ..., and the fact that there are thermodynamic variables which are uniquely specified by the equilibrium state ... are not conclusions deduced logically from some philosophical


id: thermodynamic-equilibrium-20260505-5
file: data/en.wikipedia.org/wiki/Thermodynamic_equilibrium-5.md
category: reference
title: Thermodynamic equilibrium
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_equilibrium
date_saved: 2026-05-05T10:57:27.731222+00:00
instance: kb-cron
parent: thermodynamic-equilibrium-20260505-0
summary:
He then writes: "When the conditions for all three types of equilibrium are satisfied, the system is said to be in a state of thermodynamic equilibrium". P.M. Morse writes that thermodynamics is concerned with "states of thermodynamic equilibrium". He also uses the phrase "thermal equilibrium" while discussing transfer of energy as heat between a body and a heat reservoir in its surroundings, though not explicitly defining a special term 'thermal equilibrium'. J.R. Waldram writes of "a definite thermodynamic state". He defines the term "thermal equilibrium" for a system "when its observables have ceased to change over time". But shortly below that definition he writes of a piece of glass that has not yet reached its "full thermodynamic equilibrium state". Considering equilibrium states, M. Bailyn writes: "Each intensive variable has its own type of equilibrium." He then defines thermal equilibrium, mechanical equilibrium, and material equilibrium. Accordingly, he writes: "If all the intensive variables become uniform, thermodynamic equilibrium is said to exist." He is not here considering the presence of an external force field. J.G. Kirkwood and I. Oppenheim define thermodynamic equilibrium as follows: "A system is in a state of thermodynamic equilibrium if, during the time period allotted for experimentation, (a)


id: thermodynamic-equilibrium-20260505-6
file: data/en.wikipedia.org/wiki/Thermodynamic_equilibrium-6.md
category: reference
title: Thermodynamic equilibrium
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_equilibrium
date_saved: 2026-05-05T10:57:27.731222+00:00
instance: kb-cron
parent: thermodynamic-equilibrium-20260505-0
summary:
== Characteristics of a state of internal thermodynamic equilibrium == === Homogeneity in the absence of external forces === A thermodynamic system consisting of a single phase in the absence of external forces, in its own internal thermodynamic equilibrium, is homogeneous. This means that the material in any small volume element of the system can be interchanged with the material of any other geometrically congruent volume element of the system, and the effect is to leave the system thermodynamically unchanged. In general, a strong external force field makes a system of a single phase in its own internal thermodynamic equilibrium inhomogeneous with respect to some intensive variables. For example, a relatively dense component of a mixture can be concentrated by centrifugation. === Uniform temperature === Such equilibrium inhomogeneity, induced by external forces, does not occur for the intensive variable temperature. According to E.A. Guggenheim, "The most important conception of thermodynamics is temperature." Planck introduces his treatise with a brief account of heat and temperature and thermal equilibrium, and then announces: "In the following we shall deal chiefly with homogeneous, isotropic bodies of any form, possessing throughout their substance the same temperature and density, and subject to a uniform pressure acting


id: thermodynamic-equilibrium-20260505-7
file: data/en.wikipedia.org/wiki/Thermodynamic_equilibrium-7.md
category: reference
title: Thermodynamic equilibrium
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_equilibrium
date_saved: 2026-05-05T10:57:27.731222+00:00
instance: kb-cron
parent: thermodynamic-equilibrium-20260505-0
summary:
=== Approach to thermodynamic equilibrium within an isolated system === When a body of material starts from a non-equilibrium state of inhomogeneity or chemical non-equilibrium, and is then isolated, it spontaneously evolves towards its own internal state of thermodynamic equilibrium. It is not necessary that all aspects of internal thermodynamic equilibrium be reached simultaneously; some can be established before others. For example, in many cases of such evolution, internal mechanical equilibrium is established much more rapidly than the other aspects of the eventual thermodynamic equilibrium. Another example is that, in many cases of such evolution, thermal equilibrium is reached much more rapidly than chemical equilibrium. === Fluctuations within an isolated system in its own internal thermodynamic equilibrium === In an isolated system, thermodynamic equilibrium by definition persists over an indefinitely long time. In classical physics it is often convenient to ignore the effects of measurement and this is assumed in the present account. To consider the notion of fluctuations in an isolated thermodynamic system, a convenient example is a system specified by its extensive state variables, internal energy, volume, and mass composition. By definition they are time-invariant. By definition, they combine with time-invariant nominal values of their conjugate intensive functions


id: thermodynamic-equilibrium-20260505-8
file: data/en.wikipedia.org/wiki/Thermodynamic_equilibrium-8.md
category: reference
title: Thermodynamic equilibrium
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_equilibrium
date_saved: 2026-05-05T10:57:27.731222+00:00
instance: kb-cron
parent: thermodynamic-equilibrium-20260505-0
summary:
A system's internal state of thermodynamic equilibrium should be distinguished from a "stationary state" in which thermodynamic parameters are unchanging in time but the system is not isolated, so that there are, into and out of the system, non-zero macroscopic fluxes which are constant in time. Non-equilibrium thermodynamics is a branch of thermodynamics that deals with systems that are not in thermodynamic equilibrium. Most systems found in nature are not in thermodynamic equilibrium because they are changing or can be triggered to change over time, and are continuously and discontinuously subject to flux of matter and energy to and from other systems. The thermodynamic study of non-equilibrium systems requires more general concepts than are dealt with by equilibrium thermodynamics. Many natural systems still today remain beyond the scope of currently known macroscopic thermodynamic methods. Laws governing systems which are far from equilibrium are also debatable. One of the guiding principles for these systems is the maximum entropy production principle. It states that a non-equilibrium system evolves such as to maximize its entropy production. == See also == Thermodynamic models Non-random two-liquid model (NRTL model) - Phase equilibrium calculations UNIQUAC model - Phase equilibrium calculations Time crystal Topics in control theory


id: thermodynamic-equilibrium-20260505-9
file: data/en.wikipedia.org/wiki/Thermodynamic_equilibrium-9.md
category: reference
title: Thermodynamic equilibrium
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_equilibrium
date_saved: 2026-05-05T10:57:27.731222+00:00
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parent: thermodynamic-equilibrium-20260505-0
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== Cited bibliography == Adkins, C.J. (1968/1983). Equilibrium Thermodynamics, third edition, McGraw-Hill, London, ISBN 0-521-25445-0. Bailyn, M. (1994). A Survey of Thermodynamics, American Institute of Physics Press, New York, ISBN 0-88318-797-3. Beattie, J.A., Oppenheim, I. (1979). Principles of Thermodynamics, Elsevier Scientific Publishing, Amsterdam, ISBN 0-444-41806-7. Boltzmann, L. (1896/1964). Lectures on Gas Theory, translated by S.G. Brush, University of California Press, Berkeley. Buchdahl, H.A. (1966). The Concepts of Classical Thermodynamics, Cambridge University Press, Cambridge UK. Callen, H.B. (1960/1985). Thermodynamics and an Introduction to Thermostatistics, (1st edition 1960) 2nd edition 1985, Wiley, New York, ISBN 0-471-86256-8. Carathéodory, C. (1909). Untersuchungen über die Grundlagen der Thermodynamik, Mathematische Annalen, 67: 355–386. A translation may be found here. Also a mostly reliable translation is to be found at Kestin, J. (1976). The Second Law of Thermodynamics, Dowden, Hutchinson & Ross, Stroudsburg PA. Chapman, S., Cowling, T.G. (1939/1970). The Mathematical Theory of Non-uniform gases. An Account of the Kinetic Theory of Viscosity, Thermal Conduction and Diffusion in Gases, third edition 1970, Cambridge University Press, London. Crawford, F.H. (1963). Heat, Thermodynamics, and Statistical Physics, Rupert Hart-Davis, London, Harcourt, Brace & World, Inc. de Groot, S.R., Mazur, P. (1962). Non-equilibrium Thermodynamics, North-Holland, Amsterdam. Reprinted (1984), Dover Publications Inc.,


id: thermodynamic-system-20260505-0
file: data/en.wikipedia.org/wiki/Thermodynamic_system-0.md
category: reference
title: Thermodynamic system
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_system
date_saved: 2026-05-05T10:57:28.904227+00:00
instance: kb-cron
parent: thermodynamic-system-20260505-0
summary:
A thermodynamic system is a body of matter and/or radiation separate from its surroundings that can be studied using the laws of thermodynamics. Thermodynamic systems can be passive and active according to internal processes. According to internal processes, passive systems and active systems are distinguished: passive, in which there is a redistribution of available energy, active, in which one type of energy is converted into another. Depending on its interaction with the environment, a thermodynamic system may be an isolated system, a closed system, or an open system. An isolated system does not exchange matter or energy with its surroundings. A closed system may exchange heat, experience forces, and exert forces, but does not exchange matter. An open system can interact with its surroundings by exchanging both matter and energy. The physical condition of a thermodynamic system at a given time is described by its state, which can be specified by the values of a set of thermodynamic state variables. A thermodynamic system is in thermodynamic equilibrium when there are no macroscopically apparent flows of matter or energy within it or between it and other systems. == Overview == Thermodynamic equilibrium is characterized not only by the absence of any


id: thermodynamic-system-20260505-1
file: data/en.wikipedia.org/wiki/Thermodynamic_system-1.md
category: reference
title: Thermodynamic system
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_system
date_saved: 2026-05-05T10:57:28.904227+00:00
instance: kb-cron
parent: thermodynamic-system-20260505-0
summary:
== Systems in equilibrium == In isolated systems it is consistently observed that as time goes on internal rearrangements diminish and stable conditions are approached. Pressures and temperatures tend to equalize, and matter arranges itself into one or a few relatively homogeneous phases. A system in which all processes of change have gone practically to completion is considered in a state of thermodynamic equilibrium. The thermodynamic properties of a system in equilibrium are unchanging in time. Equilibrium system states are much easier to describe in a deterministic manner than non-equilibrium states. In some cases, when analyzing a thermodynamic process, one can assume that each intermediate state in the process is at equilibrium. Such a process is called quasistatic. For a process to be reversible, each step in the process must be reversible. For a step in a process to be reversible, the system must be in equilibrium throughout the step. That ideal cannot be accomplished in practice because no step can be taken without perturbing the system from equilibrium, but the ideal can be approached by making changes slowly. The very existence of thermodynamic equilibrium, defining states of thermodynamic systems, is the essential, characteristic, and most fundamental postulate of thermodynamics,


id: thermodynamic-system-20260505-2
file: data/en.wikipedia.org/wiki/Thermodynamic_system-2.md
category: reference
title: Thermodynamic system
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_system
date_saved: 2026-05-05T10:57:28.904227+00:00
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parent: thermodynamic-system-20260505-0
summary:
Adiabatic boundary – not allowing any heat exchange: A thermally isolated system Rigid boundary – not allowing exchange of work: A mechanically isolated system One example is fluid being compressed by a piston in a cylinder. Another example of a closed system is a bomb calorimeter, a type of constant-volume calorimeter used in measuring the heat of combustion of a particular reaction. Electrical energy travels across the boundary to produce a spark between the electrodes and initiates combustion. Heat transfer occurs across the boundary after combustion but no mass transfer takes place either way. The first law of thermodynamics for energy transfers for closed system may be stated: Δ U = Q − W {\displaystyle \Delta U=Q-W} where U {\displaystyle U} denotes the internal energy of the system, Q {\displaystyle Q} heat added to the system, W {\displaystyle W} the work done by the system. For infinitesimal changes the first law for closed systems may stated: d U = δ Q − δ W . {\displaystyle \mathrm {d} U=\delta Q-\delta W.} If the work is due to a volume expansion by d V {\displaystyle \mathrm {d} V} at a pressure P {\displaystyle P} then: δ W = P d V


id: thermodynamic-system-20260505-3
file: data/en.wikipedia.org/wiki/Thermodynamic_system-3.md
category: reference
title: Thermodynamic system
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_system
date_saved: 2026-05-05T10:57:28.904227+00:00
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parent: thermodynamic-system-20260505-0
summary:
== Selective transfer of matter == For a thermodynamic process, the precise physical properties of the walls and surroundings of the system are important, because they determine the possible processes. An open system has one or several walls that allow transfer of matter. To account for the internal energy of the open system, this requires energy transfer terms in addition to those for heat and work. It also leads to the idea of the chemical potential. A wall selectively permeable only to a pure substance can put the system in diffusive contact with a reservoir of that pure substance in the surroundings. Then a process is possible in which that pure substance is transferred between system and surroundings. Also, across that wall a contact equilibrium with respect to that substance is possible. By suitable thermodynamic operations, the pure substance reservoir can be dealt with as a closed system. Its internal energy and its entropy can be determined as functions of its temperature, pressure, and mole number. A thermodynamic operation can render impermeable to matter all system walls other than the contact equilibrium wall for that substance. This allows the definition of an intensive state variable, with respect to a reference


id: thermodynamic-system-20260505-4
file: data/en.wikipedia.org/wiki/Thermodynamic_system-4.md
category: reference
title: Thermodynamic system
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermodynamic_system
date_saved: 2026-05-05T10:57:28.904227+00:00
instance: kb-cron
parent: thermodynamic-system-20260505-0
summary:
== Sources == Abbott, M.M.; van Hess, H. G. (1989). Thermodynamics with Chemical Applications (2nd ed.). McGraw Hill. Bailyn, M. (1994). A Survey of Thermodynamics. New York: American Institute of Physics Press. ISBN 0-88318-797-3. Callen, H. B. (1985) [1960]. Thermodynamics and an Introduction to Thermostatistics (2nd ed.). New York: Wiley. ISBN 0-471-86256-8. Carnot, Sadi (1824). Réflexions sur la puissance motrice du feu et sur les machines propres à développer cette puissance (in French). Paris: Bachelier. Haase, R. (1971). "Survey of Fundamental Laws". In Eyring, H.; Henderson, D.; Jost, W. (eds.). Thermodynamics. Physical Chemistry: An Advanced Treatise. Vol. 1. New York: Academic Press. pp. 1–97. LCCN 73-117081. Dobroborsky B.S. Machine safety and the human factor / Edited by Doctor of Technical Sciences, prof. S.A. Volkov. — St. Petersburg: SPbGASU, 2011. — pp. 33–35. — 114 p. — ISBN 978-5-9227-0276-8. (Ru) Halliday, David; Resnick, Robert; Walker, Jearl (2008). Fundamentals of Physics (8th ed.). Wiley. Moran, Michael J.; Shapiro, Howard N. (2008). Fundamentals of Engineering Thermodynamics (6th ed.). Wiley. Rex, Andrew; Finn, C. B. P. (2017). Finn's Thermal Physics (3rd ed.). Taylor & Francis. ISBN 978-1-498-71887-5. Tisza, László (1966). Generalized Thermodynamics. MIT Press. Tschoegl, N. W. (2000). Fundamentals of Equilibrium and Steady-State Thermodynamics.


id: thermogravitational-cycle-20260505-0
file: data/en.wikipedia.org/wiki/Thermogravitational_cycle-0.md
category: reference
title: Thermogravitational cycle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thermogravitational_cycle
date_saved: 2026-05-05T10:57:30.084117+00:00
instance: kb-cron
parent: thermogravitational-cycle-20260505-0
summary:
A thermogravitational cycle is a reversible thermodynamic cycle using the gravitational works of weight and buoyancy to respectively compress and expand a working fluid. == Theoretical framework == Consider a column filled with a transporting medium and a balloon filled with a working fluid. Due to the hydrostatic pressure of the transporting medium, the pressure inside the column increases along the z axis (see figure). Initially, the balloon is inflated by the working fluid at temperature TC and pressure P0 and located on top of the column. A thermogravitational cycle is decomposed into four ideal steps: 1→2: Descent of the balloon towards the bottom of the column. The working fluid undergoes adiabatic compression with its temperature increasing and its pressure reaching value Ph at the bottom (Ph>P0). 2→3: While the ballon lays at the bottom, the working fluid receives heat from the hot source at temperature TH and undergoes isobaric expansion at pressure Ph. 3→4: The balloon rises towards the column top. The working fluid undergoes adiabatic expansion with a drop in temperature and reaches pressure P0 after expansion when the balloon is on top. 4→1: Once arrived on top, the working fluid supplies heat to the cold source at


id: transpiration-cooling-20260505-0
file: data/en.wikipedia.org/wiki/Transpiration_cooling-0.md
category: reference
title: Transpiration cooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Transpiration_cooling
date_saved: 2026-05-05T10:57:31.278415+00:00
instance: kb-cron
parent: transpiration-cooling-20260505-0
summary:
Transpiration cooling is a thermodynamic process where cooling is achieved by a process of moving a liquid or a gas through the wall of a structure to absorb some portion of the heat energy from the structure while simultaneously actively reducing the convective and radiative heat flux coming into the structure from the surrounding space. One approach to transpiration cooling is to move liquid through small pores in the outer wall of a body leading to evaporation of the liquid to a gas via the physical mechanism of evaporative cooling. Other approaches are possible. == Applications == Transpiration cooling is used in the aerospace industry, in jet and rocket engines. In 2018, researchers at the University of Oxford were experimentally testing transpiration cooling as a Thermal Protection System for Hypersonic Vehicles such as rockets or spaceplanes. Transpiration cooling is one of a variety of cooling techniques that may be used to reduce regenerative cooling loads in rocket engines and subsequently reduce propellant requirements. Other techniques exist, such as film cooling, ablative cooling, radiative cooling, heat sink cooling and dump cooling. Transpiration cooling is being considered for use in space vehicles reentering the Earth's atmosphere at hypersonic velocities where a transpirationally


id: charles-karsner-mills-20260505-0
file: data/en.wikipedia.org/wiki/Charles_Karsner_Mills-0.md
category: reference
title: Charles Karsner Mills
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Charles_Karsner_Mills
date_saved: 2026-05-05T10:57:32.860331+00:00
instance: kb-cron
parent: charles-karsner-mills-20260505-0
summary:
Charles Karsner Mills, M.D. (December 4, 1845 – May 28, 1931) was an American physician and a pioneer in neurology. He founded the first neurology department in a general hospital in the United States at the Philadelphia General Hospital in 1877 and served as chief of neurology at the Hospital of the University of Pennsylvania. He was a professor of neurology at the University of Pennsylvania from 1877 to 1915. He founded the Philadelphia Polyclinic and taught there as professor of diseases of the mind and nervous system from 1883 to 1898. He led major reforms to psychiatric hospitals in the Philadelphia area including the closing of the Blockley Almshouse and the construction of the Philadelphia General Hospital and Byberry Hospital for Mental Diseases. He published over 300 scientific papers on neurology topics including cerebral localization, electrotherapeutics, aphasias and the effects of tumors in the central nervous system. In 1900, he first described a case of ascending paralysis, a rare motor neuron condition that has become known as Mills' syndrome. == Early life and education == Mills was born on December 4, 1845, in Philadelphia, Pennsylvania, to James and Lavinia Ann (Fitzgerald) Mills. He attended Central High School but left


id: silas-weir-mitchell-physician-20260505-0
file: data/en.wikipedia.org/wiki/Silas_Weir_Mitchell_(physician)-0.md
category: reference
title: Silas Weir Mitchell (physician)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Silas_Weir_Mitchell_(physician)
date_saved: 2026-05-05T10:57:34.104016+00:00
instance: kb-cron
parent: silas-weir-mitchell-physician-20260505-0
summary:
Silas Weir Mitchell (February 15, 1829 – January 4, 1914) was an American physician, scientist, novelist, and poet. He is considered the father of medical neurology, and he discovered causalgia (complex regional pain syndrome) and erythromelalgia, and pioneered the rest cure. == Early life == Silas Weir Mitchell was born on February 15, 1829, in Philadelphia, Pennsylvania, to prominent physician and writer John Kearsley Mitchell (1792–1858) and Sarah Henry Mitchell (1800–1872). His father was a doctor and pathologist interested in snake venom, and Mitchell would continue his research later on. Dr. Mitchell studied at the University of Pennsylvania and later earned the degree of MD at the city's Jefferson Medical College in 1850. == Career == During the Civil War, he was director of treatment of nervous injuries and maladies at Turner's Lane Hospital, Philadelphia, and at the close of the war became a specialist in neurology. In this field Mitchell pioneered the rest cure for diseases now termed "psychiatric", particularly neurasthenia and hysteria, subsequently taken up by the medical world. The treatment consisted primarily in isolation, confinement to bed, dieting, electrotherapy and massage; and was popularly known as 'Dr Diet and Dr Quiet'. Mitchell also urged his female patients


id: silas-weir-mitchell-physician-20260505-1
file: data/en.wikipedia.org/wiki/Silas_Weir_Mitchell_(physician)-1.md
category: reference
title: Silas Weir Mitchell (physician)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Silas_Weir_Mitchell_(physician)
date_saved: 2026-05-05T10:57:34.104016+00:00
instance: kb-cron
parent: silas-weir-mitchell-physician-20260505-0
summary:
John Kearsley Mitchell (1859–1917), a neurologist who married Anne Keppele Williams in 1890. Langdon Elwyn Mitchell (1862–1935), a playwright who married actress Marion Lea in 1891. On June 23, 1875, Mitchell was married to Mary Cadwalader (1835–1914), who was from one of Philadelphia's most prestigious families. She was a daughter of Thomas McCall Cadwalader and Maria Charlotte Gouverneur (niece of Elizabeth Kortright, who had married U.S. President James Monroe). The marriage "propelled him to one of the city's highest social circles and he became a trustee of the University of Pennsylvania the following year." Together, they were the parents of a daughter: Marie Gouverneur Cadwalader Mitchell (1876–1898), who died unmarried. Mitchell died on January 4, 1914, in Philadelphia and is interred at The Woodlands Cemetery. His widow died a week after his funeral. === Cultural Club Founder === Mitchell and 8 other members of the University Club at Penn founded The Franklin Inn Club in 1902. === Art patron === He was a friend and patron of the artist Thomas Eakins, and owned the painting Whistling for Plover. The Philadelphia Chippendale chairs seen in several Eakins paintings – such as William Rush Carving his Allegorical Figure of Schuylkill River (1877)


id: silas-weir-mitchell-physician-20260505-2
file: data/en.wikipedia.org/wiki/Silas_Weir_Mitchell_(physician)-2.md
category: reference
title: Silas Weir Mitchell (physician)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Silas_Weir_Mitchell_(physician)
date_saved: 2026-05-05T10:57:34.104016+00:00
instance: kb-cron
parent: silas-weir-mitchell-physician-20260505-0
summary:
== Further reading == Anna Robeson Brown Burr, Weir Mitchell: His Life and Letters (Duffield & Company 1929). Nancy Cervetti, S. Weir Mitchell, 1829–1914: Philadelphia's Literary Physician. University Park, PA: Pennsylvania State University Press, 2012. ISBN 0271054042 E. P. Oberholtzer, "Personal Memories of Weir Mitchell," in the Bookman, vol. 39 (1914). p. 132 A. Proust and G. Ballet, The Treatment of Neurasthenia. 1902. Tucker, Beverly R., S. Weir Mitchell. Gorham Press, Boston, 1914. Talcott Williams, "Dr. S. Weir Mitchell" in the Century Magazine, vol. 57 (1898). Talcott Williams, in several articles in the Book News Monthly, vol. 26 (1907). A Catalogue of the Scientific and Literary Work of S. Weir Mitchell. Philadelphia, 1894. == External links == Finding aid to the S. Weir Mitchell collection at the University of Pennsylvania Libraries Silas Weir Mitchell. Biography at WhoNamedIt Silas Weir Mitchell papers from the Historic Psychiatry Collection, Menninger Archives, Kansas Historical Society Works by Silas Weir Mitchell at Project Gutenberg Works by or about Silas Weir Mitchell at the Internet Archive Works by Silas Weir Mitchell in the Ball State University Digital Media Repository Portrait of Silas Weir Mitchell by John Singer Sargent Archived July 5, 2007, at the Wayback Machine


id: andr-strohl-20260505-0
file: data/en.wikipedia.org/wiki/André_Strohl-0.md
category: reference
title: André Strohl
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/André_Strohl
date_saved: 2026-05-05T10:57:35.333123+00:00
instance: kb-cron
parent: andr-strohl-20260505-0
summary:
André Strohl (20 March 1887 – 10 March 1977) was a French physiologist who was a native of Poitiers. He is remembered for his role in the diagnosis of Guillain–Barré syndrome (sometimes called Guillain–Barré–Strohl syndrome), a form of areflexic paralysis that exhibits normal cell count but with an abnormal increase in spinal fluid protein. The syndrome is named after two French neurologists; Georges Guillain and Jean Alexandre Barré. In 1916, during World War I, Strohl was serving in the Neurological Centre of the French Sixth Army with Guillain and Barré. The three doctors noticed that two soldiers, who were suffering from muscular weakening and pain along with paresthesias, had an unexpected amount of spinal fluid protein production. Strohl is credited with performing the electrophysiological tests on the soldiers. Eventually, the two patients were able to recover from their illness. In 1916, Guillain, Barré and Strohl reported their findings in a medical journal. In 1927, H. Draganesco and J. Claudion coined the term "Guillain–Barré syndrome", apparently overlooking Strohl's contributions. In 1924 Strohl became a professor of physiological medicine in Algiers, and two years later acquired the same position at the University of Paris. He retired from there in 1957. He was


id: lag-ri-hasan-elebi-20260505-0
file: data/en.wikipedia.org/wiki/Lagâri_Hasan_Çelebi-0.md
category: reference
title: Lagâri Hasan Çelebi
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Lagâri_Hasan_Çelebi
date_saved: 2026-05-05T10:59:25.395421+00:00
instance: kb-cron
parent: lag-ri-hasan-elebi-20260505-0
summary:
Lagâri Hasan Çelebi was an Ottoman scientist, engineer and aviator who, according to the account written by traveller Evliya Çelebi, made a successful crewed rocket flight. == Account == Evliya Çelebi reported that in 1633, Lagari Hasan Çelebi blasted off from Sarayburnu, (the promontory below the Topkapı Palace in Istanbul) in a 7-winged rocket propelled by 50 okka (140 lbs) of gunpowder. The flight was said to have been undertaken at the time of the birth of Sultan Murad IV's daughter. As Evliya Celebi wrote, Lagari proclaimed before launching his craft "O my sultan! Be blessed, I am going to talk to Jesus!"; after ascending in the rocket, he landed in the sea, swimming ashore and joking "O my sultan! Jesus sends his regards to you!"; he was rewarded by the Sultan with silver and the rank of sipahi in the Ottoman army. Evliya Çelebi also mentioned another aviation pioneer, Hezârfen Ahmed Çelebi, making a flight by glider a year earlier. == Popular culture == Istanbul Beneath My Wings is a 1996 film about the lives of Lagari Hasan Çelebi, his brother and fellow aviator Hezârfen Ahmed Çelebi, and Ottoman society in the early 17th century as witnessed and narrated


id: edward-forman-20260505-0
file: data/en.wikipedia.org/wiki/Edward_Forman-0.md
category: reference
title: Edward Forman
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Edward_Forman
date_saved: 2026-05-05T10:59:26.610331+00:00
instance: kb-cron
parent: edward-forman-20260505-0
summary:
Edward Seymour Forman (December 3, 1912 – February 12, 1973) was an American engineer and inventor known for his pioneering work in early rocketry in the United States. Forman, along with his collaborators in Guggenheim Aeronautical Laboratory at the California Institute of Technology (GALCIT), demonstrated the first practical jet-assisted take-off (JATO) of an aircraft in the United States. Forman was among the GALCIT innovators that went on to found Aerojet General Corporation, the largest rocket technology manufacturer in the 1940s, and the GALCIT Rocket Research Group itself became the precursor of the Jet Propulsion Laboratory. == Early life and education == Forman was born in Gillespie, Illinois, the youngest of four brothers. The family moved to Pasadena, California and Forman attended Washington Junior High School, where he met Jack Parsons, who would become his lifelong collaborator and friend. Forman found Parsons, who was two years younger than he, being bullied at school and rescued him. Soon after that, the two boys grew a strong bond over their common interest in science fiction. Forman was an avid reader of the Barsoom series by Edgar Rice Burroughs, which is quoted as having influenced a generation of scientists and thinkers, including Carl Sagan.


id: edward-forman-20260505-1
file: data/en.wikipedia.org/wiki/Edward_Forman-1.md
category: reference
title: Edward Forman
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Edward_Forman
date_saved: 2026-05-05T10:59:26.610331+00:00
instance: kb-cron
parent: edward-forman-20260505-0
summary:
=== GALCIT Rocket Research Group === In the early 1930s, Forman and Parsons began to realize that the rocket technology was a more complex subject than they had first assumed. They corresponded with rocketry experts on both sides of the Atlantic, but Forman later reminisced that they learned very little beyond the fact that nobody else had yet achieved much.In 1935, a Los Angeles Times article titled “Rocket Plane Visualized Flying 1200 Miles Hour” caught the pair's eyes. The article covered a paper by William Bollay, an aeronautics graduate student at Caltech, on the works of Austrian engineer Eugen Sänger. When they approached Bollay, he directed them to Frank Malina, another graduate student, who was pursuing studies in rocket propulsion. Malina shared their enthusiasm about rocketry and agreed to join their efforts. The trio put together a research proposal to request funding from Caltech. Initially, Foreman and Parsons wanted to propose the development of a sounding rocket, but Malina argued in favor of a more fundamental project aimed at understanding the thermodynamics in a rocket engine through static tests. Malina later recounted that "Parsons and Forman were not too pleased with an austere program that did not include at least


id: robert-esnault-pelterie-20260505-0
file: data/en.wikipedia.org/wiki/Robert_Esnault-Pelterie-0.md
category: reference
title: Robert Esnault-Pelterie
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_Esnault-Pelterie
date_saved: 2026-05-05T10:59:27.835008+00:00
instance: kb-cron
parent: robert-esnault-pelterie-20260505-0
summary:
Robert Albert Charles Esnault-Pelterie (French pronunciation: [ʁɔbɛʁ albɛʁ ʃaʁl eno pɛltəʁi]; 8 November 1881 – 6 December 1957) was a French aircraft designer and spaceflight theorist. He is referred to as being one of the founders of modern rocketry and astronautics, along with the Russian Konstantin Tsiolkovsky, the Chinese Qian Xuesen, the Germans Hermann Oberth, Wernher von Braun and the American Robert H. Goddard. == Biography == He was born on 8 November 1881 in Paris to a textile industrialist. He was educated at the Faculté des Sciences, studying engineering at the Sorbonne. He served in World War I and was made an Officier de la Légion d'Honneur. In November 1928, on board the Ile de France while sailing to New York City, he was married to Carmen Bernaldo de Quirós, the daughter of Don Antonio and Yvonne Cabarrus, and granddaughter of General Marquis of Santiago, Grandee of Spain, Head of the Military Household of Queen Isabella II. He died on 6 December 1957 in Nice, France. == REP == Esnault-Pelterie developed and manufactured aeroplanes and aero engines under the name REP. === Aeroplanes === His first experiments in aviation were based on the Wright brothers 1902 glider. His first


id: robert-esnault-pelterie-20260505-1
file: data/en.wikipedia.org/wiki/Robert_Esnault-Pelterie-1.md
category: reference
title: Robert Esnault-Pelterie
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_Esnault-Pelterie
date_saved: 2026-05-05T10:59:27.835008+00:00
instance: kb-cron
parent: robert-esnault-pelterie-20260505-0
summary:
== Prix REP-Hirsch == The Prix REP-Hirsch was an international award of the Société astronomique de France given in recognition of the study of interplanetary travel and astronautics. Established by Esnault-Pelterie and André-Louis Hirsch, a Parisian banker and science enthusiast, it was the first prize for astronautics in the world. The award was given "to recognize the best original scientific work, theoretical or experimental, that is able to advance one of the questions related to the realisation of space travel, or to increase human understanding of one of the branches related to the science of astronautics." The idea for establishing the prize originated during a dinner Hirsch and Esnault-Pelterie organised in Paris on 26 December 1927. The guests discussed the emerging science of space travel, which they called “astronautics” at the suggestion of science fiction writer J.H. Rosny the elder. Hirsch and Esnault-Pelterie provided funds – 5,000 francs annually for 1928, 1929, and 1930 – to the Société astronomique de France, for an annual award in astronautics in their names. A Comité d'Astronautique was established to manage the prize. In addition to Esnault-Pelterie, Hirsch, and Rosny the elder, it included General Gustave-Auguste Ferrié (President), Jean Perrin and Eugène Fichot (Vice-Presidents)


id: robert-h-goddard-20260505-0
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-0.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
Robert Hutchings Goddard (October 5, 1882 – August 10, 1945) was an American physicist, inventor, and engineer credited with creating and building the world's first liquid-fueled rocket, which was successfully launched on March 16, 1926. By 1915 his pioneering work had dramatically improved the efficiency of the solid-fueled rocket, signaling the era of the modern rocket and innovation. He and his team launched 34 rockets between 1926 and 1941, achieving altitudes as high as 2.6 km (1.6 mi) and speeds as fast as 885 km/h (550 mph). Goddard's work as both theorist and engineer anticipated many of the developments that would make spaceflight possible. He has been called the man who ushered in the Space Age. Two of Goddard's 214 patented inventions, a multi-stage rocket (1914), and a liquid-fuel rocket (1914), were important milestones toward spaceflight. His 1919 monograph A Method of Reaching Extreme Altitudes is considered one of the classic texts of 20th-century rocket science. Goddard successfully pioneered modern methods such as two-axis control (gyroscopes and steerable thrust) to allow rockets to control their flight effectively. Although his work in the field was revolutionary, Goddard received little public or financial support for his research and development work. He was


id: robert-h-goddard-20260505-1
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-1.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
On this day I climbed a tall cherry tree at the back of the barn ... and as I looked toward the fields at the east, I imagined how wonderful it would be to make some device which had even the possibility of ascending to Mars, and how it would look on a small scale, if sent up from the meadow at my feet. I have several photographs of the tree, taken since, with the little ladder I made to climb it, leaning against it. It seemed to me then that a weight whirling around a horizontal shaft, moving more rapidly above than below, could furnish lift by virtue of the greater centrifugal force at the top of the path. I was a different boy when I descended the tree from when I ascended. Existence at last seemed very purposive. For the rest of his life, he observed October 19 as "Anniversary Day", a private commemoration of the day of his greatest inspiration. == Education and early studies == The young Goddard was a thin and frail boy, almost always in fragile health. He suffered from stomach problems, pleurisy, colds, and bronchitis, and he fell two years behind his classmates.


id: robert-h-goddard-20260505-2
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-2.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
=== First scientific writings === The high-school student summed up his ideas on space travel in a proposed article, "The Navigation of Space," which he submitted to the Popular Science News. The journal's editor returned it, saying that they could not use it "in the near future." While still an undergraduate, Goddard wrote a paper proposing a method for balancing airplanes using gyro-stabilization. He submitted the idea to Scientific American, which published the paper in 1907. Goddard later wrote in his diaries that he believed his paper was the first proposal of a way to automatically stabilize aircraft in flight. His proposal came around the same time as other scientists were making breakthroughs in developing functional gyroscopes. While studying physics at WPI, ideas came to Goddard's mind that sometimes seemed impossible, but he was compelled to record them for future investigation. He wrote that "there was something inside which simply would not stop working." He purchased some cloth-covered notebooks and began filling them with a variety of thoughts, mostly concerning his dream of space travel. He considered centrifugal force, radio waves, magnetic reaction, solar energy, atomic energy, ion or electrostatic propulsion and other methods to reach space. After experimenting with


id: robert-h-goddard-20260505-3
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-3.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
=== Foundational patents === In the technological and manufacturing atmosphere of Worcester, patents were considered essential, not only to protect original work but as documentation of first discovery. He began to see the importance of his ideas as intellectual property, and thus began to secure those ideas before someone else did—and he would have to pay to use them. In May 1913, he wrote descriptions concerning his first rocket patent applications. His father brought them to a patent lawyer in Worcester who helped him to refine his ideas for consideration. Goddard's first patent application was submitted in October 1913. In 1914, his first two landmark patents were accepted and registered. The first, U.S. patent 1,102,653, described a multi-stage rocket fueled with a solid "explosive material." The second, U.S. patent 1,103,503, described a rocket fueled with a solid fuel (explosive material) or with liquid propellants (gasoline and liquid nitrous oxide). The two patents would eventually become important milestones in the history of rocketry. Overall, 214 patents were published, some posthumously by his wife. == Early rocketry research == In the fall of 1914 Goddard's health had improved, and he accepted a part-time position as an instructor and research fellow at Clark


id: robert-h-goddard-20260505-4
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-4.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
=== Smithsonian Institution sponsorship === By 1916, the cost of Goddard's rocket research had become too great for his modest teaching salary to bear. He began to solicit potential sponsors for financial assistance, beginning with the Smithsonian Institution, the National Geographic Society, and the Aero Club of America. In his letter to the Smithsonian in September 1916, Goddard claimed he had achieved a 63% efficiency and a nozzle velocity of almost 2438 meters per second. With these performance levels, he believed a rocket could vertically lift a weight of 1 lb (0.45 kg) to a height of 232 miles (373 km) with an initial launch weight of only 89.6 lbs (40.64 kg). (Earth's atmosphere can be considered to end at 80 to 100 miles (130 to 160 km) altitude, where its drag effect on orbiting satellites becomes minimal.) The Smithsonian was interested and asked Goddard to elaborate upon his initial inquiry. Goddard responded with a detailed manuscript he had already prepared, entitled A Method of Reaching Extreme Altitudes. In January 1917, the Smithsonian agreed to provide Goddard with a five-year grant totaling US$5000. Afterward, Clark was able to contribute US$3500 and the use of their physics lab to the project.


id: robert-h-goddard-20260505-5
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-5.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
== A Method of Reaching Extreme Altitudes == In 1919 Goddard thought that it would be premature to disclose the results of his experiments because his engine was not sufficiently developed. Webster realized that Goddard had accomplished a good deal of fine work and insisted that Goddard publish his progress so far or he would take care of it himself, so Goddard asked the Smithsonian Institution if it would publish the report, updated with notes, that he had submitted in late 1916. In late 1919, the Smithsonian published Goddard's groundbreaking work, A Method of Reaching Extreme Altitudes. The report describes Goddard's mathematical theories of rocket flight, his experiments with solid-fuel rockets, and the possibilities he saw of exploring Earth's atmosphere and beyond. Along with Konstantin Tsiolkovsky's earlier work, The Exploration of Cosmic Space by Means of Reaction Devices, Goddard's report is regarded as one of the pioneering works of the science of rocketry, and 1750 copies were distributed worldwide. Goddard also sent a copy to individuals who requested one, until his personal supply was exhausted. Smithsonian aerospace historian Frank Winter said that this paper was "one of the key catalysts behind the international rocket movement of the 1920s and 30s."


id: robert-h-goddard-20260505-6
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-6.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
As a method of sending a missile to the higher, and even highest, part of the earth's atmospheric envelope, Professor Goddard's multiple-charge rocket is a practicable, and therefore promising device. Such a rocket, too, might carry self-recording instruments, to be released at the limit of its flight, and conceivable parachutes would bring them safely to the ground. It is not obvious, however, that the instruments would return to the point of departure; indeed, it is obvious that they would not, for parachutes drift exactly as balloons do. The article pressed further on Goddard's proposal to launch rockets beyond the atmosphere: [A]fter the rocket quits our air and really starts on its longer journey, its flight would be neither accelerated nor maintained by the explosion of the charges it then might have left. To claim that it would be is to deny a fundamental law of dynamics, and only Dr. Einstein and his chosen dozen, so few and fit, are licensed to do that. ... Of course, [Goddard] only seems to lack the knowledge ladled out daily in high schools. Thrust is however possible in a vacuum. ==== Aftermath ==== A week after the New York Times editorial, Goddard released a


id: robert-h-goddard-20260505-7
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-7.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
Goddard began experimenting with liquid oxidizer, liquid fuel rockets in September 1921, and successfully tested the first liquid propellant engine in November 1923. It had a cylindrical combustion chamber, using impinging jets to mix and atomize liquid oxygen and gasoline. In 1924–25, Goddard had problems developing a high-pressure piston pump to send fuel to the combustion chamber. He wanted to scale up the experiments, but his funding would not allow such growth. He decided to forgo the pumps and use a pressurized fuel feed system applying pressure to the fuel tank from a tank of inert gas, a technique that is still used today. The liquid oxygen, some of which evaporated, provided its own pressure. On December 6, 1925, he tested the simpler pressure feed system. He conducted a static test on the firing stand at the Clark University physics laboratory. The engine successfully lifted its own weight in a 27-second test in the static rack. It was a major success for Goddard, proving that a liquid fuel rocket was possible. The test moved Goddard an important step closer to launching a rocket with liquid fuel. Goddard conducted an additional test in December, and two more in January 1926. After


id: robert-h-goddard-20260505-8
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-8.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
=== Guggenheim sponsorship === In the spring of 1930, Lindbergh finally found an ally in the Guggenheim family. Financier Daniel Guggenheim agreed to fund Goddard's research over the next four years for a total of $100,000 (~$2.4 million today). The Guggenheim family, especially Harry Guggenheim, would continue to support Goddard's work in the years to come. The Goddards soon moved to Roswell, New Mexico Because of the military potential of the rocket, Goddard, Lindbergh, Harry Guggenheim, the Smithsonian Institution and others tried in 1940, before the U.S. entered World War II, to convince the Army and Navy of its value. Goddard's services were offered, but there was no interest, initially. Two young, imaginative military officers eventually got the services to attempt to contract with Goddard just prior to the war. The Navy beat the Army to the punch and secured his services to build variable-thrust, liquid-fueled rocket engines for jet-assisted take-off (JATO) of aircraft. These rocket engines were the precursors to the larger throttlable rocket plane engines that helped launch the space age. Astronaut Buzz Aldrin wrote that his father, Edwin Aldrin Sr. "was an early supporter of Robert Goddard." The elder Aldrin was a student of physics under Goddard


id: robert-h-goddard-20260505-9
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-9.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
With new financial backing, Goddard eventually relocated to the Eden Valley Test Site in Roswell, New Mexico, in summer of 1930, where he worked with his team of technicians in near-isolation and relative secrecy for years. He had consulted a meteorologist as to the best area to do his work, and Roswell seemed ideal. Here they would not endanger anyone, would not be bothered by the curious and would experience a more moderate climate (which was also better for Goddard's health). The locals valued personal privacy, knew Goddard desired his, and when travelers asked where Goddard's facilities were located, they would likely be misdirected. By September 1931, his rockets had the now familiar appearance of a smooth casing with tail-fins. He began experimenting with gyroscopic guidance and made a flight test of such a system in April 1932. A gyroscope mounted on gimbals electrically controlled steering vanes in the exhaust, similar to the system used by the German V-2 over 10 years later. Though the rocket crashed after a short ascent, the guidance system had worked, and Goddard considered the test a success. A temporary loss of funding from the Guggenheims, as a result of the depression, forced Goddard in


id: robert-h-goddard-20260505-10
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-10.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
=== General Jimmy Doolittle === Jimmy Doolittle was introduced to the field of space science at an early point in its history. He recalls in his autobiography, "I became interested in rocket development in the 1930s when I met Robert H. Goddard, who laid the foundation. ... While with Shell Oil I worked with him on the development of a type of fuel. ... " Harry Guggenheim and Charles Lindbergh arranged for (then Major) Doolittle to discuss with Goddard a special blend of gasoline. Doolittle flew himself to Roswell in October 1938 and was given a tour of Goddard's shop and a "short course" in rocketry. He then wrote a memo, including a rather detailed description of Goddard's rocket. In closing he said, "interplanetary transportation is probably a dream of the very distant future, but with the moon only a quarter of a million miles away—who knows!" In July 1941, he wrote Goddard that he was still interested in his rocket propulsion research. The Army was interested only in JATO at this point. However, Doolittle and Lindbergh were concerned about the state of rocketry in the US, and Doolittle remained in touch with Goddard. Shortly after World War II, Doolittle


id: robert-h-goddard-20260505-11
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-11.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
== Annapolis, Maryland == Navy Lieutenant Charles F. Fischer, who had visited Goddard in Roswell earlier and gained his confidence, believed Goddard was doing valuable work and was able to convince the Bureau of Aeronautics in September 1941 that Goddard could build the JATO unit the Navy desired. While still in Roswell, and before the Navy contract took effect, Goddard began in September to apply his technology to build a variable-thrust engine to be attached to a PBY seaplane. By May 1942, he had a unit that could meet the Navy's requirements and be able to launch a heavily loaded aircraft from a short runway. In February, he received part of a PBY with bullet holes apparently acquired in the Pearl Harbor attack. Goddard wrote to Guggenheim that "I can think of nothing that would give me greater satisfaction than to have it contribute to the inevitable retaliation." In April, Fischer notified Goddard that the Navy wanted to do all its rocket work at the Engineering Experiment Station at Annapolis. Esther, worried that a move to the climate of Maryland would cause Robert's health to deteriorate faster, objected. But the patriotic Goddard replied, "Esther, don't you know there's a war


id: robert-h-goddard-20260505-12
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-12.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
In its 1942 crash effort to perfect an aircraft booster, the Navy was beginning to learn its way in rocketry. In similar efforts, the Army Air Corps was also exploring the field [with GALCIT]. Compared to Germany's massive program, these beginnings were small, yet essential to later progress. They helped develop a nucleus of trained American rocket engineers, the first of the new breed who would follow the professor into the Age of Space. In August 1943, President Atwood at Clark wrote to Goddard that the university was losing the acting head of the physics department, was taking on "emergency work" for the army, and he was to "report for duty or declare the position vacant." Goddard replied that he believed he was needed by the navy, was nearing retirement age, and was unable to lecture because of his throat problem, which did not allow him to talk above a whisper. He regretfully resigned as professor of physics and expressed his deepest appreciation for all Atwood and the trustees had done for him and indirectly for the war effort. In June he had gone to see a throat specialist in Baltimore, who recommended that he not talk at all, to


id: robert-h-goddard-20260505-13
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-13.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
In the spring of 1945, Goddard saw a captured German V-2 ballistic missile, in the naval laboratory in Annapolis, Maryland, where he had been working under contract. The unlaunched rocket had been captured by the US Army from the Mittelwerk factory in the Harz mountains in Germany and samples began to be shipped by Special Mission V-2 on 22 May 1945. After a thorough inspection, Goddard was convinced that the Germans had "stolen" his work. Though the design details were not exactly the same, the basic design of the V-2 was similar to one of Goddard's rockets. The V-2, however, was technically far more advanced than the most successful of the rockets designed and tested by Goddard. The Peenemünde rocket group led by Wernher von Braun may have benefited from the pre-1939 contacts to a limited extent, but had also started from the work of their own space pioneer, Hermann Oberth; they also had the benefit of intensive state funding, large-scale production facilities (using slave labor), and repeated flight-testing that allowed them to refine their designs. Oberth was a space flight theorist and had never built a rocket, but he tested small liquid propellant thrust chambers in 1929–30 which were


id: robert-h-goddard-20260505-14
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-14.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
== Goddard's secrecy == Goddard avoided sharing details of his work with other scientists and preferred to work alone with his technicians. Frank Malina, who was then studying rocketry at the California Institute of Technology, visited Goddard in August 1936. Goddard hesitated to discuss any of his research, other than that which had already been published in Liquid-Propellant Rocket Development. Theodore von Kármán, Malina's mentor at the time, was unhappy with Goddard's attitude and later wrote, "Naturally we at Caltech wanted as much information as we could get from Goddard for our mutual benefit. But Goddard believed in secrecy. ... The trouble with secrecy is that one can easily go in the wrong direction and never know it." However, at an earlier point, von Kármán said that Malina was "highly enthusiastic" after his visit and that Caltech made changes to their liquid-propellant rocket, based on Goddard's work and patents. Malina remembered his visit as friendly and that he saw all but a few components in Goddard's shop. Goddard's concerns about secrecy led to criticism for failure to cooperate with other scientists and engineers. His approach at that time was that independent development of his ideas without interference would bring quicker


id: robert-h-goddard-20260505-15
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-15.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
== Personal life == On June 21, 1924, Goddard married Esther Christine Kisk (March 31, 1901 – June 4, 1982), a secretary in Clark University's President's office, whom he had met in 1919. She became enthusiastic about rocketry and photographed some of his work as well as aided him in his experiments and paperwork, including accounting. They enjoyed going to the movies in Roswell and participated in community organizations such as the Rotary and the Woman's Club. He painted the New Mexican scenery, sometimes with the artist Peter Hurd, and played the piano. She played bridge, while he read. Esther said Robert participated in the community and readily accepted invitations to speak to church and service groups. The couple did not have children. After his death, she sorted out Goddard's papers, and secured 131 additional patents on his work. She also filmed some of the experiments that took place across the course of Goddard's research. Concerning Goddard's religious views, he was raised as an Episcopalian, though he was not outwardly religious. The Goddards were associated with the Episcopal church in Roswell, and he attended occasionally. He once spoke to a young people's group on the relationship of science and religion.


id: robert-h-goddard-20260505-16
file: data/en.wikipedia.org/wiki/Robert_H._Goddard-16.md
category: reference
title: Robert H. Goddard
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Robert_H._Goddard
date_saved: 2026-05-05T10:59:29.313605+00:00
instance: kb-cron
parent: robert-h-goddard-20260505-0
summary:
U.S. patent 1,102,653 – Rocket apparatus U.S. patent 1,103,503 – Rocket apparatus U.S. patent 2395113A – Mechanism for feeding combustion liquids to rocket apparatus U.S. patent 2397657A – Control mechanism for rocket apparatus U.S. patent 2397659A – Control mechanism for rocket apparatus U.S. patent 2511979A – Vacuum tube transportation system – E. C. Goddard The Guggenheim Foundation and Goddard's estate filed suit in 1951 against the U.S. government for prior infringement of three of Goddard's patents. In 1960, the parties settled the suit, and the U.S. armed forces and NASA paid out an award of $1 million: half of the award settlement went to his wife, Esther. At that time, it was the largest government settlement ever paid in a patent case. The settlement amount exceeded the total amount of all the funding that Goddard received for his work, throughout his entire career. === Important firsts === First American to explore mathematically the practicality of using rocket propulsion to reach high altitudes and to traject to the Moon (1912) First to receive a U.S. patent on the idea of a multistage rocket (1914) First to static test a rocket in a systematic, scientific manner, measuring thrust, exhaust velocity and efficiency.


id: william-moore-mathematician-20260505-0
file: data/en.wikipedia.org/wiki/William_Moore_(mathematician)-0.md
category: reference
title: William Moore (mathematician)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/William_Moore_(mathematician)
date_saved: 2026-05-05T10:59:30.502385+00:00
instance: kb-cron
parent: william-moore-mathematician-20260505-0
summary:
William Moore (fl. 1806 – c. 1823) was a British mathematician and early contributor to rocket theory. He worked at the Royal Military Academy, Woolwich. His 1813 Treatise was the first exposition of rocket mechanics based on Newton's third law of motion. Little is known of his life, because many relevant historical documents were destroyed by German bombing in World War II. == Publications == Theory on the motion of Rockets (1810) A Treatise on the Doctrine of Fluxations (1811) A Treatise on the Motion of Rockets; to which is added, an Essay on Naval Gunnery (1813) == See also == Konstantin Tsiolkovsky Tsiolkovsky rocket equation == References ==


id: hermann-oberth-20260505-0
file: data/en.wikipedia.org/wiki/Hermann_Oberth-0.md
category: reference
title: Hermann Oberth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hermann_Oberth
date_saved: 2026-05-05T10:59:31.776683+00:00
instance: kb-cron
parent: hermann-oberth-20260505-0
summary:
Hermann Julius Oberth (German: [ˈhɛrman ˈjuːli̯ʊs ˈoːbɛrt]; 25 June 1894 – 28 December 1989) was an Austro-Hungarian-born German physicist and rocket pioneer of Transylvanian Saxon descent. Oberth supported Nazi Germany's war effort and received the War Merit Cross (1st Class) in 1943. == Early life == Oberth was born into a Transylvanian Saxon family in Nagyszeben (Hermannstadt), Kingdom of Hungary (today Sibiu in Romania); and besides his native German, he was fluent in Hungarian and Romanian as well. At the age of 11, Oberth's interest in rocketry was sparked by the novels of Jules Verne, especially From the Earth to the Moon and Around the Moon. He was fond of reading them over and over until they were engraved in his memory. As a result, Oberth constructed his first model rocket as a school student at the age of 14. In his youthful experiments, he arrived independently at the concept of the multistage rocket. During this time, however, he lacked the resources to put his ideas into practice. In 1912, Oberth began studying medicine in Munich, Germany, but after World War I broke out, he was drafted into the Imperial German Army, assigned to an infantry battalion, and sent to


id: hermann-oberth-20260505-1
file: data/en.wikipedia.org/wiki/Hermann_Oberth-1.md
category: reference
title: Hermann Oberth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hermann_Oberth
date_saved: 2026-05-05T10:59:31.776683+00:00
instance: kb-cron
parent: hermann-oberth-20260505-0
summary:
Oberth's student Max Valier joined forces with Fritz von Opel to create the world's first large-scale experimental rocket program Opel-RAK, leading to speed records for ground and rail vehicles and the world's first rocket plane. Opel RAK.1, a purpose-built design by Julius Hatry, was demonstrated to the public and world media on September 30, 1929, piloted by von Opel. Valier's and von Opel's demonstrations had a strong and long-lasting impact on later spaceflight pioneers, in particular on another of Oberth's students, Wernher von Braun. Shortly after the Opel RAK team's successful liquid-fuel rocket launches of April 10 and 12, 1929 by Friedrich Wilhelm Sander at Opel Rennbahn in Rüsselsheim, Oberth conducted in the autumn of 1929 a static firing of his first liquid-fueled rocket motor, which he named the Kegeldüse. The engine was built by Klaus Riedel in a workshop space provided by the Reich Institution of Chemical Technology, and although it lacked a cooling system, it did run briefly. He was helped in this experiment by an 18-year-old student Wernher von Braun, who would later become a giant in both German and American rocket engineering from the 1940s onward, culminating with the gigantic Saturn V rockets that made it


id: hermann-oberth-20260505-2
file: data/en.wikipedia.org/wiki/Hermann_Oberth-2.md
category: reference
title: Hermann Oberth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hermann_Oberth
date_saved: 2026-05-05T10:59:31.776683+00:00
instance: kb-cron
parent: hermann-oberth-20260505-0
summary:
=== Space Mirror === In 1923, Oberth initially outlined the concept of his space mirrors in his book Die Rakete zu den Planetenräumen (The Rocket to Interplanetary Space). These mirrors, with diameters ranging from 100 to 300 km, were envisioned to be composed of a grid network consisting of individually adjustable facets. Oberth's concept of space mirrors in orbit around the Earth serves the purpose of focusing sunlight on specific regions of the planet's surface or redirecting it into space. This approach differs from creating shaded areas at the Lagrange point between the Earth and the Sun, as it does not involve diminishing solar radiation across the entire exposed surface. According to Oberth, these colossal orbital mirrors possess the potential to illuminate individual cities, safeguard against natural disasters, manipulate weather patterns and climate, and even create additional living space for billions of people. He places significant emphasis on their capacity to influence the trajectories of barometric high and low-pressure areas. However, it is important to acknowledge that the implementation of such climate engineering interventions, including space mirrors, requires further extensive research before their practical applicability can be fully realized. Further publications followed in which he took into account the technical


id: hermann-oberth-20260505-3
file: data/en.wikipedia.org/wiki/Hermann_Oberth-3.md
category: reference
title: Hermann Oberth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hermann_Oberth
date_saved: 2026-05-05T10:59:31.776683+00:00
instance: kb-cron
parent: hermann-oberth-20260505-0
summary:
== Tasks in World War II == From 1923 to 1938 Oberth worked — with short breaks in 1929 and 1930 — as a high school teacher for physics and mathematics in his home region, Transylvania in Romania. The Romanian Oberth, who was professionally known worldwide and had many foreign contacts, was regarded as a security risk for the secrecy of the development work on the V-2, the world's first large rocket, in Peenemünde. Therefore, from June 1938 he was given a two-year research contract with the German Research Institute for Aviation (DVL) at the Vienna University of Technology and then from July 1940 at the University of Technology Dresden. When he wanted to return to Transylvania in May 1941, he received German citizenship and was conscripted in August 1941 under the alias "Friedrich Hann" to the Army Research Institute Peenemünde, where the V-2 rocket was developed under the direction of Wernher von Braun. Oberth was not involved in this work, but placed in the patent review, and wrote various reports, for example "About the best outline of multi-stage rockets" and about "Defense against enemy planes with large, remote-controlled solid missile". (Oberth criticized the V-2 design because, in his view,


id: hermann-oberth-20260505-4
file: data/en.wikipedia.org/wiki/Hermann_Oberth-4.md
category: reference
title: Hermann Oberth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hermann_Oberth
date_saved: 2026-05-05T10:59:31.776683+00:00
instance: kb-cron
parent: hermann-oberth-20260505-0
summary:
1927: Honorary member of the German Verein für Raumschiffahrt (Space Flight Association), Berlin 1929: International Award for Astronautics (Robert Esnault-Pelterie-Hirsch-Award) of the Société astronomique de France, Paris 1946: Honorary Member of the Astronautical Section of the French Academy of Sciences, Paris 1948: Honorary President of the Gesellschaft für Weltraumforschung (Society for Space Research), Stuttgart, Germany 1949: Honorary memberships of the British Interplanetary Society, London / Dansk Selskab for Rumfartsforskening, Copenhagen / Pacific Rocket Society / Detroit Rocket Society and of Northwest German Society for Space Flight 1950: The Gesellschaft für Weltraumforschung (Society for Space Research) donates the Hermann Oberth Medal 1951: Honorary President of the Detroit Rocket Society 1952: Honorary President of the Deutsche Raketen-Gesellschaft (German Rocket Society), Bremen, Germany 1952: Honorary President of the Vereinigte Astronautische Vereinigung (United Astronautical Association), Leipzig 1953: Honorary member of the Schweizerischen Arbeitsgemeinschaft für Raumfahrt (Swiss Association for Astronautics), Lucerne 1954: Diesel Medal in gold from the Deutschen Erfinderverbandes (German Inventors' Association), Nuremberg 1954: Honorary memberships of the Austrian Society for Space Research, Vienna and of the German Association of Inventors 1955: Plaque of Honor of the American Astronautical Society 1956: Edward Pendray Award from the American Rocket Society, New York 1958: The American


id: hermann-oberth-20260505-5
file: data/en.wikipedia.org/wiki/Hermann_Oberth-5.md
category: reference
title: Hermann Oberth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hermann_Oberth
date_saved: 2026-05-05T10:59:31.776683+00:00
instance: kb-cron
parent: hermann-oberth-20260505-0
summary:
Hermann Oberth is memorialized by the Hermann Oberth Space Travel Museum in Feucht, Germany, and by the Hermann Oberth Society. The museum brings together scientists, researchers, engineers, and astronauts from the East and the West to carry on his work in rocketry and space exploration. In 1980, Oberth was inducted into the International Air & Space Hall of Fame at the San Diego Air & Space Museum. The Danish Astronautical Society has named Hermann Oberth an honorary member. In Romania, the Faculty of Engineering of Lucian Blaga University of Sibiu is named after him. In 1994, a memorial house was established in Mediaș on the 100th anniversary of his birth. It exhibits various items related to rocket technology and space travel, and also has an audio-video room for documentary films. He discovered the Oberth effect (powered flyby or Oberth maneuver), a fuel-saving strategy for interplanetary space flight that is commonly used today. There are also a crater on the Moon and asteroid 9253 Oberth named after him. In Star Trek III: The Search for Spock, the USS Grissom was classified as an Oberth-class starship. Several other Oberth-class starships also appeared in subsequent Star Trek films and television series. == Books


id: nikolai-tikhomirov-chemical-engineer-20260505-0
file: data/en.wikipedia.org/wiki/Nikolai_Tikhomirov_(chemical_engineer)-0.md
category: reference
title: Nikolai Tikhomirov (chemical engineer)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Nikolai_Tikhomirov_(chemical_engineer)
date_saved: 2026-05-05T10:59:32.998036+00:00
instance: kb-cron
parent: nikolai-tikhomirov-chemical-engineer-20260505-0
summary:
Nikolai Ivanovich Tikhomirov (Russian: Николай Иванович Тихомиров; born Nikolai Viktorovich Slyotov; November 1859 – 28 April 1930) was a Russian and Soviet chemical engineer, inventor, founder of the Gas Dynamics Laboratory, specialist in rocket technology and one of the inventors of the Katyusha, which he was awarded the Hero of Socialist Labor (1991, posthumously). A crater on the far side of the Moon is named after him. == Biography == Born in November 1859 in Moscow, to a noble family of a real state councilor. His birth name was Nikolai Viktorovich Slyotov. In the 1880s, he took a pseudonym for himself, the name of his childhood friend Nikolai, the son of the merchant Ivan Tikhomirov. Subsequently, the pseudonym became his official surname. === Early years === After graduating from the lyceum, he studied at the chemical department of the Faculty of Physics and Mathematics of the Imperial Moscow University. After graduation, he worked in the technical laboratory of the Imperial Moscow University and at Kiev University in the laboratory of Professor Nikolai Bunge, who gave popular lectures on the production of "nutritional and flavoring substances". From the mid-1880s, he worked in various fields of industry, first as an assistant to


id: nikolai-tikhomirov-chemical-engineer-20260505-1
file: data/en.wikipedia.org/wiki/Nikolai_Tikhomirov_(chemical_engineer)-1.md
category: reference
title: Nikolai Tikhomirov (chemical engineer)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Nikolai_Tikhomirov_(chemical_engineer)
date_saved: 2026-05-05T10:59:32.998036+00:00
instance: kb-cron
parent: nikolai-tikhomirov-chemical-engineer-20260505-0
summary:
With the assistance of the Commander-in-Chief of the Armed Forces of the Soviet Republic Sergey Kamenev, who instructed to allocate funding for Tikhomirov's workshop, on 1 March 1921, the country's first research and development organization for the development of smokeless powder shells began its work at the military department - " Laboratory for the development of inventions by N. I. Tikhomirov. In 1924, under the leadership of N.I. Tikhomirov, a recipe for smokeless pyroxylin powder was created on a non-volatile solvent - TNT, which differs from black smoke powder in powerful and stable combustion. In 1925 Tikhomirov's laboratory moved to Leningrad. On 3 March 1928, the first launch of a rocket on smokeless powder was carried out at one of the training grounds in the Leningrad region, which had a range of about 1,300 metres. This design served as the foundation for the creation of rockets for the famous Katyusha rocket launcher. In July 1928, the laboratory of N. I. Tikhomirov was renamed the Gas Dynamics Laboratory (GDL) of the Military Scientific Committee under the Revolutionary Military Council of the USSR. Under the leadership of Tikhomirov he personally prepared calculations and drawings of a 3-inch rocket projectile. Equipment for pressing


id: konstantin-tsiolkovsky-20260505-0
file: data/en.wikipedia.org/wiki/Konstantin_Tsiolkovsky-0.md
category: reference
title: Konstantin Tsiolkovsky
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Konstantin_Tsiolkovsky
date_saved: 2026-05-05T10:59:34.323294+00:00
instance: kb-cron
parent: konstantin-tsiolkovsky-20260505-0
summary:
Konstantin Eduardovich Tsiolkovsky (; Russian: Константин Эдуардович Циолковский, IPA: [kənstɐnʲˈtʲin ɪdʊˈardəvʲɪtɕ tsɨɐlˈkofskʲɪj] ; 17 September [O.S. 5 September] 1857 – 19 September 1935) was a Russian rocket scientist who pioneered astronautics. Along with Hermann Oberth and Robert H. Goddard, he is one of the pioneers of space flight and the founding father of modern rocketry and astronautics. His works later inspired Wernher von Braun and leading Soviet rocket engineers Sergei Korolev and Valentin Glushko, who contributed to the success of the Soviet space program. Tsiolkovsky spent most of his life in a log house on the outskirts of Kaluga, about 200 km (120 mi) southwest of Moscow. A recluse by nature, his unusual habits made him appear eccentric to his fellow townsfolk. == Early life == Tsiolkovsky was born in Izhevskoye (now in Spassky District, Ryazan Oblast), in the Russian Empire, to a middle-class family. His father, Makary Edward Erazm Ciołkowski, was a Polish forester of Roman Catholic faith who relocated to Russia. His Russian Orthodox mother Maria Ivanovna Yumasheva was of mixed Volga Tatar and Russian origin. According to family tradition, Tsiolkovsky family is of the Zaporozhian Cossack descent, related to Cossack Hetman Nalyvaiko. His father was successively a


id: konstantin-tsiolkovsky-20260505-1
file: data/en.wikipedia.org/wiki/Konstantin_Tsiolkovsky-1.md
category: reference
title: Konstantin Tsiolkovsky
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Konstantin_Tsiolkovsky
date_saved: 2026-05-05T10:59:34.323294+00:00
instance: kb-cron
parent: konstantin-tsiolkovsky-20260505-0
summary:
Tsiolkovsky stated that he developed the theory of rocketry only as a supplement to philosophical research on the subject. He wrote more than 400 works including approximately 90 published pieces on space travel and related subjects. Among his works are designs for rockets with steering thrusters, multistage boosters, space stations, airlocks for exiting a spaceship into the vacuum of space, and closed-cycle biological systems to provide food and oxygen for space colonies. Tsiolkovsky's first scientific study dates back to 1880–1881. He wrote a paper called "Theory of Gases," in which he outlined the basis of the kinetic theory of gases, but after submitting it to the Russian Physico-Chemical Society (RPCS), he was informed that his discoveries had already been made 25 years earlier. Undaunted, he pressed ahead with his second work, "The Mechanics of the Animal Organism". It received favorable feedback, and Tsiolkovsky was made a member of the Society. Tsiolkovsky's main works after 1884 dealt with four major areas: the scientific rationale for the all-metal balloon (airship), streamlined airplanes and trains, hovercraft, and rockets for interplanetary travel. In 1892, he was transferred to a new teaching post in Kaluga where he continued to experiment. During this period, Tsiolkovsky began


id: konstantin-tsiolkovsky-20260505-2
file: data/en.wikipedia.org/wiki/Konstantin_Tsiolkovsky-2.md
category: reference
title: Konstantin Tsiolkovsky
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Konstantin_Tsiolkovsky
date_saved: 2026-05-05T10:59:34.323294+00:00
instance: kb-cron
parent: konstantin-tsiolkovsky-20260505-0
summary:
The result of the first publication was not what Tsiolkovsky expected. No foreign scientists appreciated his research, which today is a major scientific discipline. In 1911, he published the second part of the work "Exploration of Outer Space by Means of Rocket Devices". Here Tsiolkovsky evaluated the work needed to overcome the force of gravity, determined the speed needed to propel the device into the Solar System ("escape velocity"), and examined calculation of flight time. The publication of this article made a splash in the scientific world, and Tsiolkovsky found many friends among his fellow scientists. In 1926–1929, Tsiolkovsky solved the practical problem regarding the role played by rocket fuel in getting to escape velocity and leaving the Earth. He showed that the final speed of the rocket depends on the rate of gas flowing from it and on how the weight of the fuel relates to the weight of the empty rocket. Tsiolkovsky conceived a number of ideas that have been later used in rockets. They include: gas rudders (graphite) for controlling a rocket's flight and changing the trajectory of its center of mass, the use of components of the fuel to cool the outer shell of the spacecraft


id: konstantin-tsiolkovsky-20260505-3
file: data/en.wikipedia.org/wiki/Konstantin_Tsiolkovsky-3.md
category: reference
title: Konstantin Tsiolkovsky
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Konstantin_Tsiolkovsky
date_saved: 2026-05-05T10:59:34.323294+00:00
instance: kb-cron
parent: konstantin-tsiolkovsky-20260505-0
summary:
In 1964, The Monument to the Conquerors of Space was erected to celebrate the achievements of the Soviet people in space exploration. Located in Moscow, the monument is 107 meters (350 feet) tall and covered with titanium cladding. The main part of the monument is a giant obelisk topped by a rocket and resembling in shape the exhaust plume of the rocket. A statue of Konstantin Tsiolkovsky, the precursor of astronautics, is located in front of the obelisk. The State Museum of the History of Cosmonautics in Kaluga now bears his name. His residence during the final months of his life (also in Kaluga) was converted into a memorial museum a year after his death. The town Uglegorsk in Amur Oblast was renamed Tsiolkovsky by President of Russia Vladimir Putin in 2015. The crater Tsiolkovskiy, the most prominent crater on the far side of the Moon, was named after him. Asteroid 1590 Tsiolkovskaja was named after his wife. The Soviet Union obtained naming rights by operating Luna 3, the first space device to successfully transmit images of the side of the Moon not seen from Earth. The Tsiolkovsky Memorial Apartment. A museum created in Borovsk where he lived and had


id: franz-abdon-ulinski-20260505-0
file: data/en.wikipedia.org/wiki/Franz_Abdon_Ulinski-0.md
category: reference
title: Franz Abdon Ulinski
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Franz_Abdon_Ulinski
date_saved: 2026-05-05T10:59:35.505970+00:00
instance: kb-cron
parent: franz-abdon-ulinski-20260505-0
summary:
Franz Abdon Ulinski (1890–1974) was an Austrian engineer who was known for his early proposals in spacecraft propulsion. == Biography == Born in Mladějov na Moravě, Moravia (now part of the Czech Republic), Ulinski completed his secondary education in Linz, Austria, in 1910 before joining the Austro-Hungarian Army. Ulinski served in various roles and as a technical officer in the aviation corps during World War I. In 1919, Ulinski proposed a spacecraft design powered by jets of electrons or ions. He published his ideas in a Viennese aeronautical journal in 1920, outlining two potential energy sources: solar panels for energy storage and atomic disintegration for power generation. At the time, his propulsion concepts were not widely adopted, likely due to the energy requirements needed to escape Earth's gravity. Ulinski's work is recognized for anticipating later advancements in ion propulsion technology. Ion thrusters have been utilized in spacecraft such as Deep Space One, which conducted flybys of an asteroid and approached a comet, as well as in the stabilization of satellites in Earth orbit. == References ==


id: wan-hu-20260505-0
file: data/en.wikipedia.org/wiki/Wan_Hu-0.md
category: reference
title: Wan Hu
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wan_Hu
date_saved: 2026-05-05T10:59:36.699508+00:00
instance: kb-cron
parent: wan-hu-20260505-0
summary:
Wan Hu is an alleged Chinese official described in modern sources as possibly the first man to attempt to use a rocket to launch into outer space. Possibly depicted as the "world's first astronaut" and "the first martyr in man's struggle to achieve space flight", NASA named the crater Wan-Hoo on the far side of the Moon after him. According to some Chinese sources, "Wan Hu" was a title granted to him by the imperial court during the early Ming dynasty, and his real name was Tao Chengdao. As a Ming official, he was interested in technological innovation, particularly concerning rockets. He is said to have died in 1390. While the legend is well-known, there is no direct evidence surviving to substantiate it. According to Joseph Needham, the story is dubious and may be invented during or after the Chinoiserie period, considering the lack of firm historical reference. However, Li Chengzhi has argued for the story's plausibility, saying that it may have come from oral transmission by European missionaries who came to China during the late Ming and Qing dynasties, or based on records in an ancient Chinese document that has been subsequently lost. == Legend == === Basic story


id: heinrich-albers-sch-nberg-20260505-0
file: data/en.wikipedia.org/wiki/Heinrich_Albers-Schönberg-0.md
category: reference
title: Heinrich Albers-Schönberg
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Heinrich_Albers-Schönberg
date_saved: 2026-05-05T10:59:38.191109+00:00
instance: kb-cron
parent: heinrich-albers-sch-nberg-20260505-0
summary:
Heinrich Ernst Albers-Schönberg (21 January 1865 – 4 June 1921) was a German gynecologist and radiologist. He was a native of Hamburg. He studied medicine at the Universities of Tübingen and Leipzig, where in 1891 he earned his medical doctorate under the guidance of Heinrich Curschmann (1846-1910). From 1892 to 1894 he was an assistant at Hamburg-Eppendorf Hospital, afterwards working as an assistant to gynecologist Paul Zweifel (1848–1927) at the University of Leipzig. Soon afterwards, he settled in Hamburg as a medical practitioner. In 1897, with internist Georg Deycke (1865–1938), he established an X-ray clinic and laboratory in Hamburg. Later, he was appointed head of the radiology department at St Georg Hospital. In 1919 he became a full professor and chair of radiology at the newly established University of Hamburg. Albers-Schönberg is credited with providing a description of osteopetrosis, a condition sometimes referred to as "Albers-Schönberg disease". It is described as a syndrome of excessive bone calcification causing a marble-like appearance with increased radiological density of the skeleton. He was an early specialist in the field of radiological medicine. In 1903 he discovered that exposure to radiation caused damage to the reproductive glands of rabbits. In cooperation with other scientists,


id: samuel-barbour-20260505-0
file: data/en.wikipedia.org/wiki/Samuel_Barbour-0.md
category: reference
title: Samuel Barbour
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Samuel_Barbour
date_saved: 2026-05-05T10:59:39.359709+00:00
instance: kb-cron
parent: samuel-barbour-20260505-0
summary:
Samuel Barbour (1860 – 3 June 1938) was an Australian chemist, photographer and X-ray pioneer in the colony of South Australia. In Australia, the medical men of the day took a slow approach in the adoption of the new science that involved X-rays. Many of the early demonstrations were made by investigators outside the medical field. Upon examination of the initial investigators, several key factors were common. The individuals had already either been experimenting along similar lines to Wilhelm Röntgen with Crookes tubes and such, the physicists or scientists, or were actively associated with electrical work, the electricians, which made them particularly receptive to the technical appeal of the new science of X-rays. Records of the events reveal that among the medical men who witnessed the first images produced as radiographs, a rather small number had any great desire to employ X-rays directly in their own medical practice. After the early investigative work of Thomas Ranken Lyle, William Henry Bragg, Joseph Patrick Slattery, and others, almost all medical men were satisfied with soliciting the services of the external X-ray man when necessity arose for skiagraphs to be produced. As the utilization of X-rays became more acceptable, the involvement of electricians


id: lucien-blake-20260505-0
file: data/en.wikipedia.org/wiki/Lucien_Blake-0.md
category: reference
title: Lucien Blake
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Lucien_Blake
date_saved: 2026-05-05T10:59:40.546374+00:00
instance: kb-cron
parent: lucien-blake-20260505-0
summary:
Lucien Ira Blake (September 12, 1853 – May 11, 1916) was an American professor of physics and engineering at the University of Kansas. He pioneered studies in underwater sound transmission, the use of X-rays in medicine and electrochemistry. Blake Hall in the University of Kansas was named after him. == Life and work == Blake was born in Mansfield, Massachusetts, where his father Mortimer Blake (1813-1884) was a Congregationalist minister married to Harriet Louisa Daniels (1817-1906). After graduating from Amherst College in 1877, he went to the University of Berlin where he received a PhD with studies under Heinrich Hertz. He returned to take up a position in 1885 at the Rose Polytechnic Institute in Terre Haute, Indiana. Here he conducted experiments on underwater acoustic communication. He experimented on an underwater communication system off Sandy Hook, New Jersey. He patented several inventions and in 1887 he moved to the University of Kansas. Here he set up a four year course in electrical engineering. From 1892 he managed to set up a new physical and electrical laboratory which came to be called "Blake Hall" in 1898 (it was demolished in 1963). In 1893 he was declared one of the 40 most


id: william-henry-bragg-20260505-0
file: data/en.wikipedia.org/wiki/William_Henry_Bragg-0.md
category: reference
title: William Henry Bragg
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/William_Henry_Bragg
date_saved: 2026-05-05T10:59:41.784235+00:00
instance: kb-cron
parent: william-henry-bragg-20260505-0
summary:
Sir William Henry Bragg (2 July 1862 – 12 March 1942) was a British X-ray crystallographer who uniquely shared a Nobel Prize with his son Lawrence Bragg – the 1915 Nobel Prize in Physics "for their services in the analysis of crystal structure by means of X-rays," an important step in the development of X-ray crystallography. == Early life and education == William Henry Bragg was born on 2 July 1862 in Westward, Cumberland, England, the son of Robert John Bragg, a merchant marine officer and farmer, and Mary Wood, a clergyman's daughter. His mother died when he was age 7, and was raised by his uncle (also named William Bragg) at Market Harborough. He was educated at the Grammar School there, at King William's College on the Isle of Man, and—having won an exhibition—at Trinity College, Cambridge. He graduated in 1884 as third Wrangler, and in 1885 earned First Class Honours in the mathematical Tripos. == Career and research == === University of Adelaide === In 1885, Bragg was appointed Elder Professor of Mathematics and Physics at the University of Adelaide in Australia, and started work there in early 1886. Being a skilled mathematician, at that time he had


id: william-henry-bragg-20260505-1
file: data/en.wikipedia.org/wiki/William_Henry_Bragg-1.md
category: reference
title: William Henry Bragg
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/William_Henry_Bragg
date_saved: 2026-05-05T10:59:41.784235+00:00
instance: kb-cron
parent: william-henry-bragg-20260505-0
summary:
=== University of Leeds === From 1909 to 1915, Bragg was Cavendish Professor of Physics at the University of Leeds. He continued his work on X-rays with much success. He invented the X-ray spectrometer and with his son, Lawrence, then a research student at Cambridge, founded the new science of X-ray crystallography, the analysis of crystal structure using X-ray diffraction. === World War I === Both of his sons, Lawrence and Robert, were called into the army after the First World War broke out in 1914 . The following year, Bragg was appointed Quain Professor of Physics at University College London. He had to wait for almost a year to contribute to the war effort; in July 1915, he was appointed to the Board of Invention and Research set up by the Admiralty. In September, his younger son Robert died of wounds at Gallipoli. In November, he shared the Nobel Prize in Physics with Lawrence. The Navy was struggling to prevent sinkings by unseen, submerged U-boats. The scientists recommended that the best tactic was to listen for the submarines. The Navy had a hydrophone research establishment at Aberdour, Scotland, staffed with navy men. In November 1915, two young physicists were


id: william-henry-bragg-20260505-2
file: data/en.wikipedia.org/wiki/William_Henry_Bragg-2.md
category: reference
title: William Henry Bragg
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/William_Henry_Bragg
date_saved: 2026-05-05T10:59:41.784235+00:00
instance: kb-cron
parent: william-henry-bragg-20260505-0
summary:
== Commemoration == The Electoral district of Bragg in the South Australian House of Assembly was created in 1970, and was named after both William and Lawrence Bragg. The lecture theatre of King William's College (KWC) is named in memory of Bragg; the Sixth-Form invitational literary debating society at KWC, the Bragg Society, is also named in his memory. One of the school "Houses" at Robert Smyth School, Market Harborough, Leicester, is named "Bragg" in memory of him being a student there. Since 1992, the Australian Institute of Physics has awarded the Bragg Gold Medal for excellence in physics for the best Ph.D. thesis by a student at an Australian university. The two sides of the medal contain the images of Sir William Henry and his son Sir Lawrence Bragg. The Experimental Technique Centre at Brunel University is named the Bragg Building. The Sir William Henry Bragg Building at the University of Leeds opened in 2021. In 1962, the Bragg Laboratories were constructed at the University of Adelaide to commemorate 100 years since the birth of Sir William H. Bragg. The Australian Bragg Centre for Proton Therapy and Research also in Adelaide, Australia was completed in late 2023. It is


id: frederick-woodward-branson-20260505-0
file: data/en.wikipedia.org/wiki/Frederick_Woodward_Branson-0.md
category: reference
title: Frederick Woodward Branson
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Frederick_Woodward_Branson
date_saved: 2026-05-05T10:59:42.987261+00:00
instance: kb-cron
parent: frederick-woodward-branson-20260505-0
summary:
Frederick Woodward Branson, FIC, FCS (6 March 1851 – 30 November 1933) was a British chemist, glassblower, instrument maker and X-ray pioneer. He worked with Jacob Bell & Co a chemist who reformed the profession, location Oxford Street London. He was a Fellow of the Chemical Society in 1882, and became a Fellow of the Institute of Chemistry in 1888, glassblower, instrument maker and X-ray pioneer. Chairman & managing director of Reynolds & Branson 1898 – 1933. He had many published works 1882–1918. He was given the honorary award of Freeman of the City of London 1908. == Life and times of Frederick W. Branson and his family == Frederick Woodward Branson was born on 6 March 1851 at Hanslope, Newport Pagnell, Buckinghamshire, England. He was the son of Thomas Branson a bricklayer, who later became a farmer. Branson's father inherited the farm via his marriage to Sarah Ann née Woodward, who had inherited it from her father. In 1861, Branson lived with his parents and maternal grandparents, William Woodward an agricultural labourer and farm owner, at Hungate End Farm, Hanslope. The farm consisted of 168 acres (68 ha) and employed six men and six boys. William inherited when he


id: frederick-woodward-branson-20260505-1
file: data/en.wikipedia.org/wiki/Frederick_Woodward_Branson-1.md
category: reference
title: Frederick Woodward Branson
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Frederick_Woodward_Branson
date_saved: 2026-05-05T10:59:42.987261+00:00
instance: kb-cron
parent: frederick-woodward-branson-20260505-0
summary:
== The History of Reynolds and Branson Ltd Co 1816–1972 == The original company can be traced back to 1816 (see Grace's Guide which is the leading source of historical information on industry and manufacturing in Britain, The Company was established in 1816) Edward Matterson druggist who was running the firm at 12, Briggate, Leeds in 1822, Matterson was educated at Leeds Grammar School, the company had moved to 13 Briggate, Leeds by 1829 (1822 Baines's Directory and Gazette Edward Matterson is a druggist, and dealer in paint and colours, Location 12, Briggate, Leeds ) (Edward Matterson in Pigot's Directory of 1829 he is still druggist but now located 13 Briggate & 4 Blundel place)(also Noted Baines's Directory 1822 John Cudworth Hop Merchants was located at 13, Briggate Leeds ) (Noted William West is a druggist, located at 14, Briggate in 1822. ) Edward Matterson had been employed by Allen and Hanburys, in 1833 William West F.R.S. took over the company after Matterson went bankrupt (see The bankrupt directory: being a complete register of all the bankrupts, with their residences, trades, and dates when they appeared in the London gazette, from December 1820 to April 1843 ). In 1839 Thomas


id: frederick-woodward-branson-20260505-2
file: data/en.wikipedia.org/wiki/Frederick_Woodward_Branson-2.md
category: reference
title: Frederick Woodward Branson
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Frederick_Woodward_Branson
date_saved: 2026-05-05T10:59:42.987261+00:00
instance: kb-cron
parent: frederick-woodward-branson-20260505-0
summary:
Noted that it was a sad end to a company which had been based in Leeds, in some form or another for 156 years.


id: frederick-woodward-branson-20260505-3
file: data/en.wikipedia.org/wiki/Frederick_Woodward_Branson-3.md
category: reference
title: Frederick Woodward Branson
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Frederick_Woodward_Branson
date_saved: 2026-05-05T10:59:42.987261+00:00
instance: kb-cron
parent: frederick-woodward-branson-20260505-0
summary:
== Reynolds and Branson chronology == 1822, Edward Matterson druggist, dealer in paint and colours, Location 12, Briggate, Leeds Baines's Directory and Gazette. 1829, Edward Matterson, druggist, located 13 Briggate & 4 Blundel place. Pigot's Directory 1833, William West F.R.S. took over the company after Matterson went bankrupt, see The bankrupt directory London gazette, from December 1820 to April 1843. 1839, Thomas Harvey, chemist and druggist, 5 Commercial Street. Leeds. 1841, Thomas Harvey, chemist and druggist, 13 Briggate. Leeds. 1854, Reynolds returned to Leeds as partner with Harvey in the chemist business and the firm became Harvey & Reynolds. 1856, Harvey & Reynolds, chemist and druggist, 13 Briggate. Leeds. 1861, Harvey, Reynolds & Fowler. Chemist and druggist, 10 Briggate. Leeds. 1864, Haw & Reynolds. Chemist and druggist. Briggate. Leeds. as Thomas Harvey had retired. 1867, Haw, Reynolds, & Co. Chemist and druggist. Briggate. Leeds. 1872, Haw, Reynolds & Co. Chemist. 14 Commercial Street, and 13 Briggate. Leeds. 1886, Reynolds & Branson. Makers of the first short clinical thermometer. 1891, Reynolds & Reynolds, chemist and druggist, 13 Briggate. Leeds 1901, Reynolds & Reynolds, chemist and druggist, 13 Briggate. Leeds 1911, Reynolds & Reynolds, chemist and druggist, 13 Briggate. Leeds == Reynolds


id: frederick-woodward-branson-20260505-4
file: data/en.wikipedia.org/wiki/Frederick_Woodward_Branson-4.md
category: reference
title: Frederick Woodward Branson
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Frederick_Woodward_Branson
date_saved: 2026-05-05T10:59:42.987261+00:00
instance: kb-cron
parent: frederick-woodward-branson-20260505-0
summary:
Radium and its Properties. "The Leeds Law Institute was, on the 23rd ult., crowded to the door on the occasion of a lecture by Mr. F. W. Branson, F.I.C., on that mysterious subject known as radium. The Leeds Geological Society and the Leeds Naturalist Club were also represented, and Mr. E. Hawkesworth was in the chair. "The new metal, which Professor Pierre Curie discovered, has, as demonstrated by Mr. Branson, some wonderful properties and a probable great future. "Mr. Branson first showed that radium is an element having the highest atomic weight known, and has a characteristic spectrum, by which it can be easily identified, and that it falls into the group of metals: barium, calcium, and strontium. He then showed the difference between atmospheric (sound) waves and ether waves (heat, light, and electrical), and alluded to the emanations given off by radium as consisting of electrons negatively charged, and also much larger particles of matter termed ions positively charged. The former have very penetrative powers as regards metals and opaque bodies, and are identical with the kathode rays that are given off in an ordinary X-ray tube. "The positively charged particles are not so penetrative; indeed, they are easily


id: frank-styant-browne-20260505-0
file: data/en.wikipedia.org/wiki/Frank_Styant_Browne-0.md
category: reference
title: Frank Styant Browne
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Frank_Styant_Browne
date_saved: 2026-05-05T10:59:44.201498+00:00
instance: kb-cron
parent: frank-styant-browne-20260505-0
summary:
Frank Styant Browne (10 July 1854 – 17 April 1938), also known as Styant Browne, was an Australian pharmacist, artist, photographer and X-ray pioneer from Tasmania. In Australia, the medical men of the day took a slow approach in the adoption of the new science that involved X-rays. Many of the early demonstrations were made by investigators outside the medical field. Upon examination of the initial investigators, several key factors were common. The individuals had already either been experimenting along similar lines to Wilhelm Röntgen with Crookes tubes and such, the physicists or scientists, or were actively associated with electrical work, the electricians, which made them particularly receptive to the technical appeal of the new science of X-rays. Records of the events reveal that among the medical men who witnessed the first images produced as radiographs, a rather small number had any great desire to employ X-rays directly in their own medical practice. After the early investigative work of Thomas Ranken Lyle, William Henry Bragg, Joseph Patrick Slattery, and others, almost all medical men were satisfied with soliciting the services of the external X-ray man when necessity arose for skiagraphs to be produced. As the utilization of X-rays became more


id: w-ironside-bruce-20260505-0
file: data/en.wikipedia.org/wiki/W._Ironside_Bruce-0.md
category: reference
title: W. Ironside Bruce
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/W._Ironside_Bruce
date_saved: 2026-05-05T10:59:45.380508+00:00
instance: kb-cron
parent: w-ironside-bruce-20260505-0
summary:
William Ironside Bruce (1876 – 21 March 1921) was a doctor in Europe who conducted early research on the use of X-rays. He headed the X-ray departments at Charing Cross Hospital and at the Hospital for Sick Children. He wrote an early book on X-ray techniques and he was president of the radiology section of the Royal Society of Medicine. In 1921, Bruce was diagnosed with aplastic anaemia, which his physicians attributed to his work with X-rays. He died two months after being diagnosed with the illness. Bruce's death led to the establishment of an X-ray safety committee in Great Britain. == Early life == Bruce was born in Dingwall, the second son of William Bruce, an Aberdeenshire doctor. His uncle was John Mitchell Bruce, a physician who wrote a widely read textbook, Materia Medica and Therapeutics. He was a cousin of Edmund Ironside, 1st Baron Ironside. Many members of the Bruce and Ironside families had come from Keig, a quiet village in Aberdeenshire. Though Bruce was not born there, he received his education in Aberdeen, in the tradition of these relatives. Bruce completed medical school in 1900 at the University of Aberdeen. After medical school he served in the


id: vernon-ellis-cosslett-20260505-0
file: data/en.wikipedia.org/wiki/Vernon_Ellis_Cosslett-0.md
category: reference
title: Vernon Ellis Cosslett
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Vernon_Ellis_Cosslett
date_saved: 2026-05-05T10:59:46.532787+00:00
instance: kb-cron
parent: vernon-ellis-cosslett-20260505-0
summary:
Vernon Ellis Cosslett, FRS (16 June 1908 – 21 November 1990) was a British microscopist. The eighth child (of six sons and five daughters) of Edgar William Cosslett (1871–1948), a Welsh cabinet maker and carpenter, clerk of works on the estate of the Earl of Eldon at Stowell Park and latterly a builder, and Anne (née Williams; 1871–1951), he was raised at Cirencester and educated at Cirencester Grammar School, the University of Bristol, the Kaiser-Wilhelm-Institut, Berlin-Dahlem, and University College, London. He was a research fellow at the University of Bristol after completing his PhD there in 1932, having been awarded an H. H. Wills Memorial Fellowship, remaining there until 1935. He then lectured at Faraday House Engineering College, London, until 1939, whilst undertaking part-time research at Birkbeck College, London. Between 1939 and 1941 he was Keddey-Fletcher-Warr Research Fellow of London University, working at the University of Oxford as a temporary lecturer, then lecturing in physics at the University of Oxford Electrical Laboratory from 1941 to 1946. From 1947, as an ICI Research Fellow, Cosslett worked with William Lawrence Bragg at the Cavendish Laboratory, Cambridge University on the electron microscope and founded the Electron Microscopy Department. He also developed improved x-ray


id: friedrich-dessauer-20260505-0
file: data/en.wikipedia.org/wiki/Friedrich_Dessauer-0.md
category: reference
title: Friedrich Dessauer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Friedrich_Dessauer
date_saved: 2026-05-05T10:59:47.719042+00:00
instance: kb-cron
parent: friedrich-dessauer-20260505-0
summary:
Friedrich Dessauer (19 July 1881 – 16 February 1963) was a German physicist, a philosopher, a socially engaged entrepreneur and a journalist. Friedrich Dessauer was born in Aschaffenburg, Kingdom of Bavaria, German Empire. As a young man he was fascinated by new discoveries in the natural sciences. He was particularly interested in the X-rays discovered by Röntgen and their medical applications. After attending the humanistic Gymnasium in Aschaffenburg, he studied electrical engineering and physics at the Technische Universität Darmstadt and the University of Munich. Due to radiation damage during his research on the use of X-rays, his face was badly damaged and he was repeatedly treated with plastic surgery. In connection with this, he was released from military service. Due to the death of his father, he initially interrupted his studies, continued in 1914 at the Goethe University Frankfurt and then completed it in 1917. From 1924 to 1933 he was a Zentrum party member of the Reichstag, the German Parliament. A practicing Catholic with a Jewish grandparent, he was imprisoned by the Nazis when they came to power for his opposition to Hitler. He was released at request of the Turkish government, who invited him to the University of


id: tienne-destot-20260505-0
file: data/en.wikipedia.org/wiki/Étienne_Destot-0.md
category: reference
title: Étienne Destot
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Étienne_Destot
date_saved: 2026-05-05T10:59:48.908017+00:00
instance: kb-cron
parent: tienne-destot-20260505-0
summary:
Étienne Destot (1 March 1864 – 3 December 1918) was a French radiologist and anatomist who was a native of Dijon. He studied medicine in Lyon, and later worked in the hospitals of Hôtel Dieu, Croix-Rousse and Charité in Lyon. In addition to his work in medicine, he was an accomplished sculptor. Destot was a pioneer in the field of radiology. In February 1896, less than two months after Wilhelm Conrad Röntgen (1845–1923) announced his discovery of the X-ray, Destot was making radiographs of patients at the Hôtel-Dieu de Lyon. He made thousands of radiographies, many of which were of patients supplied by surgeon Louis Léopold Ollier (1830–1900). In 1913, due to severe radiation damage to his hands, he was forced to relinquish his position as radiologist. Destot also made contributions in the field of orthopedics, and in 1911 is credited as being the first physician to use the term pilon in orthopedic literature. He was a medical officer during World War I, and died from illness in Châtillon-sur-Seine in 1918. His name is included on the Monument to the X-ray and Radium Martyrs of All Nations erected in Hamburg, Germany in 1936. == Associated eponym == "Destot's space", also


id: francis-john-drake-20260505-0
file: data/en.wikipedia.org/wiki/Francis_John_Drake-0.md
category: reference
title: Francis John Drake
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Francis_John_Drake
date_saved: 2026-05-05T10:59:50.102973+00:00
instance: kb-cron
parent: francis-john-drake-20260505-0
summary:
Francis John Drake, MA MB BS (Melb) (12 December 1860 - 17 December 1929) was resident medical superintendent, Launceston Hospital. In 1860, Drake was born at St. Kilda, Melbourne. On 28 April 1879, he began work as a messenger at the Melbourne Public Library with an annual salary of £50. He attended Scotch College from 1875 to 1880. In 1886, he graduated with a BA degree, and in 1887 received the MA degree from Melbourne. In 1888, Drake completed the MB from the University of Melbourne Medical School. In 1896, the Statistics of the State of Tasmania listed Drake as holding 2 appointments. He was surgeon superintendent at Launceston General Hospital with an annual salary of £400 that included quarters, rations, and fuel. The appointment began on 1 January 1890. Concurrently, Drake held the position as medical officer at the Contagious Diseases Hospital at Launceston. In 1896, Drake and Dr. John Ramsay participated in the first demonstration of X-rays by Frank Styant Browne at Launceston Hospital. The February 1898 issue of the Australasian Medical Gazette listed the resignation of Drake from the Launceston Hospital as surgeon-superintendent. The burial of Drake, who died on 17 December 1929, took place at Box


id: william-duane-physicist-20260505-0
file: data/en.wikipedia.org/wiki/William_Duane_(physicist)-0.md
category: reference
title: William Duane (physicist)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/William_Duane_(physicist)
date_saved: 2026-05-05T10:59:51.295050+00:00
instance: kb-cron
parent: william-duane-physicist-20260505-0
summary:
William Duane (February 17, 1872 – March 7, 1935) was an American physicist who conducted research on radioactivity and X-rays and their usage in the treatment of cancer. He developed the Duane-Hunt Law and Duane's hypothesis. He worked with Pierre and Marie Curie in their University of Paris laboratory for six years and developed a method for generating quantities of radon-222 "seeds" from radium for usage in early forms of brachytherapy. He was a professor at the University of Colorado Boulder, professor-emeritus and chair of biophysics at Harvard University and research fellow of physics at the Harvard Cancer Commission. He received the John Scott Medal and the Comstock Prize in Physics in 1922 and the Leonard Prize of the American Roentgen Ray Society in 1923. == Early life and education == Duane was born in Philadelphia, Pennsylvania, to Charles William and Emma Cushman (Lincoln) Duane. He was a direct descendant of Benjamin Franklin from his father's side. He received an A.B. degree in mathematics from the University of Pennsylvania in 1892 and was valedictorian of his class. He studied at Harvard University and graduated with an A.B. in 1893. He worked as an assistant to John Trowbridge in his research


id: walter-drowley-filmer-20260505-0
file: data/en.wikipedia.org/wiki/Walter_Drowley_Filmer-0.md
category: reference
title: Walter Drowley Filmer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Walter_Drowley_Filmer
date_saved: 2026-05-05T10:59:52.518100+00:00
instance: kb-cron
parent: walter-drowley-filmer-20260505-0
summary:
Walter Drowley Filmer (1 September 1865 – 24 August 1944) was an early pioneer of X-rays in Australia, a wireless engineer, for a time ran the British Royal Train, and a world class entomologist that discovered several new species in his homeland. Filmer was a naturalist and established a private collection at his residence that thousands of people visited. == Life and Times == In 1865, Filmer was born in Maitland, New South Wales, Australia. He was the son of William Filmer (1828–1902) and Amy Filmer née Hatton (1831–1901). He married Mary Anne Eliza née Chessell (1868–1951) in 1890 in Sydney. The couple had 4 children: son, Walter Harold Alexander Filmer (1892–1964), born on 10 February 1892 in Sydney; daughter, Mary Filmer (1895–1895), born in 1895 in Petersham; son, Leroy Drowley Filmer (1902–1976), born on 5 April 1902 in Newcastle; and son, Eric Filmer (1903–1986), born 10 December 1903 in Toronto. In 1944, he died at home at Lake Macquarie. In 1876, at the age of 11, he was apprenticed to a boot maker. In 1884, by the age of 19, Filmer became an assistant telegraph line repairer and operator with the New South Wales Post Office. From 1885 to


id: elizabeth-fleischman-20260505-0
file: data/en.wikipedia.org/wiki/Elizabeth_Fleischman-0.md
category: reference
title: Elizabeth Fleischman
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Elizabeth_Fleischman
date_saved: 2026-05-05T10:59:53.785949+00:00
instance: kb-cron
parent: elizabeth-fleischman-20260505-0
summary:
Elizabeth Fleischman-Aschheim (née Fleischman; March 5, 1867 – August 3, 1905) was an American radiographer who is considered a pioneer of X-ray technology. Fleischman was the first woman to die as a result of X-ray radiation exposure. == Early years == Elizabeth Fleischman was born in El Dorado County, California (possibly in Placerville), on March 5, 1867, the daughter of Jewish immigrants from the Austrian Empire. Her mother, Katherine Lezansky was born in Prague and had several family members who were physicians in what is now the Czech Republic. Her father, Jacob Fleischman, was a baker. Elizabeth was one of five children. By 1876, the family had moved to San Francisco, where Elizabeth's father worked first as a baker and later as a merchant who sold various sundries and cigars. Elizabeth Fleischman attended the Girls' High School and dropped out in her senior year in 1882 to help support her family. She then took courses in bookkeeping and office management, and for a time she worked as a bookkeeper at Friedlander & Mitau, a San Francisco underwear manufacturer. Upon the death of her mother, Fleischman moved in with her sister Estelle, who was married to English physician and surgeon Michael


id: elizabeth-fleischman-20260505-1
file: data/en.wikipedia.org/wiki/Elizabeth_Fleischman-1.md
category: reference
title: Elizabeth Fleischman
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Elizabeth_Fleischman
date_saved: 2026-05-05T10:59:53.785949+00:00
instance: kb-cron
parent: elizabeth-fleischman-20260505-0
summary:
By 1903, the cumulative effects of seven years of unprotected X-ray exposures and twelve-hour workdays began to appear as X-ray dermatitis on her hands. She attributed this irritation to the chemicals used in developing photographic plates. In early 1904, the dermatitis progressed to the point where she sought medical attention. Her doctors found:"The fingers of both hands were found to be badly ulcerated, chiefly the tissues over the middle phalanges and the middle joints....the surfaces presenting both an ulcerated and warty condition, the warts assuming the form of necrogenica-healing alternating with ulceration. All the secreting glands and hair-follicles were destroyed so that the skin was hard and dry and cracked easily. All forms of treatment by ointments and washes were without permanent benefit."She continued to work despite this injury. In 1904, she was responsible for introducing protective measures for the operators of X-ray machines. She commented on the merits of double-plate glass screens, and metals such as lead, aluminium, iron and copper to "resist" X-rays. By late 1904, the dermatitis progressed to cancer. Her doctors attempted to excise a tumor on her right hand, but this failed to halt the progression of the carcinoma. In January 1905 her entire right


id: william-hope-fowler-20260505-0
file: data/en.wikipedia.org/wiki/William_Hope_Fowler-0.md
category: reference
title: William Hope Fowler
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/William_Hope_Fowler
date_saved: 2026-05-05T10:59:54.957712+00:00
instance: kb-cron
parent: william-hope-fowler-20260505-0
summary:
William Hope Fowler CVO FRSE FRCSE (14 March 1876 – 4 October 1933) was a Scottish medical doctor and pioneer of radiology. He was co-founder of the Edinburgh School of Radiology. == Life == He was born in Edinburgh on 14 March 1876, the son of Robert Fowler, an accountant. His early years were spent at 81 Cumberland Street in Edinburgh's New Town. He was educated at Daniel Stewart's College them studied medicine at the University of Edinburgh, graduating with an MB ChB in 1897. He went to work as resident house surgeon at the Edinburgh Royal Infirmary on Lauriston Place. He showed a keen interest in the use of electricity to treat disease and was particularly interested in the newly discovered x-ray process. In 1901 he became the infirmary's Assistant Radiologist under Dawson Turner. In 1907 they were joined by John W. L. Spence. In 1911 he was promoted to Chief Radiologist alongside Archibald McKendrick. In the same year he became Honorary Radiologist to the Admiralty. At this time Fowler was living at 21 Walker Street in Edinburgh's West End. During World War I he was a member of the War Office's X-Ray Commission. In 1933 he was elected


id: wolfram-conrad-fuchs-20260505-0
file: data/en.wikipedia.org/wiki/Wolfram_Conrad_Fuchs-0.md
category: reference
title: Wolfram Conrad Fuchs
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wolfram_Conrad_Fuchs
date_saved: 2026-05-05T10:59:56.130644+00:00
instance: kb-cron
parent: wolfram-conrad-fuchs-20260505-0
summary:
Wolfram Conrad Fuchs (1865–1908) was a German-born electrical engineer who became a pioneer in radiography. He opened the first x-ray laboratory in the United States in Chicago, and had completed over 1400 x-ray examinations by 1896. His work was critical to the history of radiation protection. He was the father of Arthur Wolfram Fuchs (1895 - 1962), the inventor of the fixed kilovoltage technique of radiography. == Early life and education == Fuchs was born in Germany in 1865 to Julius and Wilhelmina Fuchs. The family emigrated to Chicago in 1870. He returned to Germany to study electrical engineering at the University of Berlin and graduated in 1889. He then went on to Paris to study at the Ecole des Beaux Arts. Upon returning to the United States, Fuchs completed his post-graduate work at the Massachusetts Institute of Technology in Boston. == Radiography work == Shortly after Wilhelm Röntgen's discovery of x-rays, Fuchs was traveling in Germany and was interested in the potential implications x-rays could have for electrical engineering. Meanwhile, in Chicago, Dr. Friedrich Cort Hamisch was also becoming interested in x-ray technology and had established a correspondence with Röntgen. He set up an x-ray laboratory but eventually handed


id: frederick-gardiner-radiologist-20260505-0
file: data/en.wikipedia.org/wiki/Frederick_Gardiner_(radiologist)-0.md
category: reference
title: Frederick Gardiner (radiologist)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Frederick_Gardiner_(radiologist)
date_saved: 2026-05-05T10:59:57.356572+00:00
instance: kb-cron
parent: frederick-gardiner-radiologist-20260505-0
summary:
Frederick Gardiner FRSE FRCSE FRSM (1874- 8 September 1933) was a Scottish radiologist and dermatologist. == Life == Gardiner was born in Edinburgh in 1874 the son of John Gardiner and his wife Isabella. He studied medicine at the University of Edinburgh graduating MB CM in 1895. He then worked as a Resident first at Stirling Royal Infirmary, then at Dundee Royal Asylum. He returned to Edinburgh for further study, gaining a diploma in Public Health in 1901. He took on a role as Leith Hospital's radiologist in 1901. He gained his doctorate (MD) in 1902 writing his thesis on x-ray use in pulmonary tuberculosis. From 1904 he worked as Assistant Physician at the Edinburgh Royal Infirmary. In 1912 he became a senior Physician and also began lecturing in dermatology at the University of Edinburgh and in extramural classes. He did much to pioneer (in retrospect now seen as a mistake) the use of x-rays in treating of skin diseases. He also worked with Sir Robert Philip on the use of x-rays to diagnose tuberculosis. He lived close to both University and Infirmary, at 9 George Square in Edinburgh (now demolished). During the First World War he worked at Bangour


id: john-hall-edwards-20260505-0
file: data/en.wikipedia.org/wiki/John_Hall-Edwards-0.md
category: reference
title: John Hall-Edwards
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/John_Hall-Edwards
date_saved: 2026-05-05T10:59:58.586277+00:00
instance: kb-cron
parent: john-hall-edwards-20260505-0
summary:
John Francis Hall-Edwards FRSE (19 December 1858 – 15 August 1926) was a British medical doctor and pioneer in the medical use of X-rays in the United Kingdom. == Life == Hall-Edwards was the son of John Edwards, and was born on Moseley Road, Kings Norton near Birmingham. He attended King Edward VI Grammar School in Birmingham. He then studied medicine, apprenticing under Prof Richard Hill Norris at Queens College Medical School. Norris was both a surgeon and keen amateur photographer, being an early user of the dry-plate process, and he familiarised Hall-Edwards with photographic techniques. Hall-Edwards was licensed to practice medicine by the Royal College of Physicians of Edinburgh. From around 1885 he shows a strong interest in photography and was President of the Midland Photographic Club 1891–93. In 1895 he was made an Honorary Member of the Royal Photographic Society following a lecture to the London Camera Club. Initially his work focussed on photography through microscopes. On 11 January 1896 he made the first use of X-rays under clinical conditions when he radiographed the hand of an associate, revealing a sterilised needle beneath the surface. A month later on 14 February he took the first radiograph to direct


id: william-john-hancock-20260505-0
file: data/en.wikipedia.org/wiki/William_John_Hancock-0.md
category: reference
title: William John Hancock
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/William_John_Hancock
date_saved: 2026-05-05T10:59:59.753329+00:00
instance: kb-cron
parent: william-john-hancock-20260505-0
summary:
William John Hancock D.Sc. (Hon), MIEE, MICE, LRCP (2 May 1864 – 26 August 1931) was an Australian of Irish descent, an electrical engineer, telephone pioneer and pioneer in X-rays in the colony of Western Australia. He was honorary radiologist for Perth Hospital and Base Hospital in Fremantle. His list of credentials and accomplishments include M.I.E.E., Member of the Institution of Electrical Engineers, M.I.C.E., Member of the Institution of Civil Engineers, L.R.C.P., Licentiate of the Royal College of Physicians and D.Sc. (Honorary). In the colonies of Australia, the medical men of the day took a slow approach in the adoption of the new science that involved x-rays. Many of the early demonstrations were made by investigators outside the medical field. Upon examination of the initial investigators, several key factors were common. The individuals had already either been experimenting along similar lines to Wilhelm Röntgen with Crookes tubes and such, the physicists or scientists, or were actively associated with electrical work, the electricians, which made them particularly receptive to the technical appeal of the new science of x-rays. Records of the events reveal that among the medical men who witnessed the first images produced as radiographs, a rather small number had


id: william-john-hancock-20260505-1
file: data/en.wikipedia.org/wiki/William_John_Hancock-1.md
category: reference
title: William John Hancock
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/William_John_Hancock
date_saved: 2026-05-05T10:59:59.753329+00:00
instance: kb-cron
parent: william-john-hancock-20260505-0
summary:
Of interest to note, when the Perth Observatory foundation was laid on 29 September 1896, the occasion was attended by Sir John Forrest and other notable dignitaries, and several items of importance were placed in a leaden box (time capsule), sealed and deposited in a cavity beneath the foundation stone. The event was described in the local press and mentioned here since "Röntgen rays tubes, and a description of the process, together with specimen photographs", donated by Hancock were included in the cache. This is the first known instance of a time capsule in Western Australia, and in Australia. In Canberra, on 3 March 1936, at the Australian Institute of Anatomy a face mask was erected in the applied anatomy museum. The bust was unveiled to commemorate Dr. William John Hancock and his service to Australia as a pioneer of X-rays and radiology in Western Australia. Royal Society of Western Australia, Kelvin Gold Medal, inaugural awardee, 1924 University of Western Australia, honorary doctorate of science, 1924 University of Western Australia, Senate, 1915–1927 === Memorial Window at University of Western Australia === In 1934, a stained glass memorial window was placed in the foyer of Winthrop Hall, at the University of


id: guido-holzknecht-20260505-0
file: data/en.wikipedia.org/wiki/Guido_Holzknecht-0.md
category: reference
title: Guido Holzknecht
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Guido_Holzknecht
date_saved: 2026-05-05T11:00:00.948626+00:00
instance: kb-cron
parent: guido-holzknecht-20260505-0
summary:
Guido Holzknecht (3 December 1872 – 30 October 1931) was an Austrian radiologist who was a native of Vienna. He studied in Strasbourg, Königsberg, and Vienna, and became the director of the X-ray laboratory at Vienna General Hospital in 1905 . He later established a central radiology department at the hospital, which became known as the Guido Holzknecht Institute. With radiologist Robert Kienböck (1871–1953), he was a co-founder of the Wiener Röntgengesellschaft (Vienna Radiology Society). The statue of Holzknecht in Arne Carlsson Park was originally made by Josef Josephu. Damaged during the Second World War, it was later restored incorrectly. The family had commissioned Josephu to show missing fingers that Holzknecht had lost due to radiation poisoning. The restored statue shows all of his fingers intact. Additionally, the signature on the restored statue reads JosefHeu, who left Vienna during the War - misspelling the original artist's name. Guido Holzknecht was a pioneer in radiology. In 1902 he devised a color dosimeter (referred to as a "chromoradiometer") for detecting and measuring X-rays. Like a number of other physicians in the early days of radiology, he died from the consequences of radiation poisoning in October 1931 aged 58. He was cremated at


id: william-henry-hosking-20260505-0
file: data/en.wikipedia.org/wiki/William_Henry_Hosking-0.md
category: reference
title: William Henry Hosking
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/William_Henry_Hosking
date_saved: 2026-05-05T11:00:02.127422+00:00
instance: kb-cron
parent: william-henry-hosking-20260505-0
summary:
William Henry Hosking LM, LSA, LRCPI, LRCP, MRCS (26 December 1841–11 March 1917) was a New Zealand medical doctor, hospital superintendent, X-ray and radium pioneer. == Life == Hosking was born in 1841 at Redruth, Cornwall, England, and christened in 1844 at Crowan, Cornwall, England. He was the son of William Hosking, an ironfounder and his wife Elizabeth Phillips. Hosking died of leukemia in 1917 at Masterton. == Education == Hosking was educated at schools in Falmouth and Taunton, then studied and trained at the Charing Cross Hospital Medical School. He achieved several qualifications that included LSA Licentiate of the Society of Apothecaries, London 1863; LRCPI Licentiate of the Royal College of Physicians in Ireland, 1873; LRCP Licentiate of the Royal College of Physicians, London; MRCS Member of the Royal College of Surgeons, England 1873; LM Doctor of Laws, University of Liverpool 1874. He registered under the Medical Practitioners Ordinance of the Province of New Munster in Campbelltown on 19 September 1863. Hosking registered on 23 September 1869 under the Medical Practitioners Act of 1867 at Ross and Masterton. == New Zealand == On 1 May 1863, Hosking departed the United Kingdom bound for the New Munster Province of New


id: richard-lane-joynt-20260505-0
file: data/en.wikipedia.org/wiki/Richard_Lane_Joynt-0.md
category: reference
title: Richard Lane Joynt
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Richard_Lane_Joynt
date_saved: 2026-05-05T11:00:03.514113+00:00
instance: kb-cron
parent: richard-lane-joynt-20260505-0
summary:
Richard Lane Joynt OBE (18 May 1866 - 8 April 1928) was an Irish orthopaedic surgeon, metallurgist, who pioneered the use of x-rays. == Early life and family == Richard Lane Joynt was born at the Grange, Raheny, County Dublin on 18 May 1866. His parents were Jane (née Russell) and William Lane-Joynt, a barrister and mayor of Limerick in 1862 and Dublin in 1867. He had four brothers and a sister. His brother, William Russell, was a barrister and philatelist and Olympic shooter. Lane Joynt spent some of his childhood in Limerick, where his father trained as a solicitor. Through his father, he was a cousin of Augusta, Lady Gregory. Lane Joynt attended the Portora Royal School, Enniskillen, County Fermanagh and entered Trinity College Dublin, graduating with an LM diploma in 1889 and MB, BCh, BAO in 1890. == Career == In 1891 he trained at the Vienna General Hospital, receiving his MD in 1893, and admitted as a fellow of the Royal College of Surgeons in Ireland (RCSI) in 1894 and elected to the County Dublin Infirmary and Meath Hospital. He served as a senior member of the RCSI council. Just two years after the invention of x-rays,


id: thomas-ranken-lyle-20260505-0
file: data/en.wikipedia.org/wiki/Thomas_Ranken_Lyle-0.md
category: reference
title: Thomas Ranken Lyle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thomas_Ranken_Lyle
date_saved: 2026-05-05T11:00:04.726229+00:00
instance: kb-cron
parent: thomas-ranken-lyle-20260505-0
summary:
Sir Thomas Ranken Lyle FRS (26 August 1860 – 31 March 1944) was an Irish-Australian mathematical physicist, radiologist, educator, and rugby player. Lyle was born and educated in Ireland before emigrating to Australia to take up a professorship at the University of Melbourne. There he was a pioneer in the use of X-rays as a medical tool. The Thomas Ranken Lyle Medal is awarded in his name to honour Australian achievements in Physics and Mathematics. In his earlier years in Ireland he was a rugby union forward of some note, who played club rugby for Dublin University and international rugby for Ireland. == Career == Lyle was born in Coleraine, Ireland in 1860, the second son of Hugh Lyle, a well-to-do landowner. He was educated at Trinity College, Dublin, graduating in 1883 with full honours and student medals for his work in mathematics and physics. He received his MA in 1887, and continued his studies in advanced physics and mathematics. By 1889 he had emigrated to Australia, and at the age of 29, took up the position of the chair of natural philosophy at the University of Melbourne. In 1891 a Master of Science was introduced at the university, and


id: cecil-lyster-20260505-0
file: data/en.wikipedia.org/wiki/Cecil_Lyster-0.md
category: reference
title: Cecil Lyster
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cecil_Lyster
date_saved: 2026-05-05T11:00:05.895253+00:00
instance: kb-cron
parent: cecil-lyster-20260505-0
summary:
Cecil Rupert Chaworth Lyster CBE (14 December 1859 – 26 January 1920) was a British physician, electrotherapist and radiologist. Lyster was the son of Alfred Chaworth Lyster and his wife Elizabeth (née Kennett). He began his career as resident medical officer at Charing Cross Hospital in London and then served as resident obstetrical officer from 1881 to 1882. Following travels in the United States and Europe, he was appointed medical superintendent of the Bolingbroke Hospital in 1885. Specialising in electro-therapeutics and radiology, he became medical officer-in-charge of the Electrical Department of Middlesex Hospital in 1902, while still continuing to work as a doctor at the Bolingbroke Hospital. He held these positions until his death. Lyster was appointed Commander of the Order of the British Empire (CBE) in January 1920 for his work in the First World War. He married Edith Thompson (died 1919) in 1903; they had no children. Lyster died from cancer caused by exposure to x-rays during his research, the day before his CBE was gazetted. The gazette was later ante-dated to two days before his death. His name is included on the Monument to the X-ray and Radium Martyrs of All Nations erected in Hamburg, Germany, in


id: monument-to-the-x-ray-and-radium-martyrs-of-all-nations-20260505-0
file: data/en.wikipedia.org/wiki/Monument_to_the_X-ray_and_Radium_Martyrs_of_All_Nations-0.md
category: reference
title: Monument to the X-ray and Radium Martyrs of All Nations
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Monument_to_the_X-ray_and_Radium_Martyrs_of_All_Nations
date_saved: 2026-05-05T11:00:07.063531+00:00
instance: kb-cron
parent: monument-to-the-x-ray-and-radium-martyrs-of-all-nations-20260505-0
summary:
The Monument to the X-ray and Radium Martyrs of All Nations (also known as the X-ray Martyrs' Memorial) is a memorial in Hamburg, Germany, commemorating those who died due to their work with the use of radiation, particularly X-rays, in medicine. It was unveiled on the grounds of St Georg (St George's) Hospital (now the Asklepios Klinik St Georg), on 4 April 1936 by the Deutsche Röntgengesellschaft (the Röntgen Society of Germany). When unveiled, the memorial included 169 names, from fifteen nations, listed alphabetically; by 1959 there were 359, with the additions listed on four separate stone plaques, beside the original columnar stone memorial. == Inscription == The memorial's inscription may be translated as: == Book == An accompanying book, Ehrenbuch der Radiologen aller Nationen (Book of Honour of radiologists of all nations) gives biographies of those commemorated. Three editions have been produced, the most recent in 1992. == Names == The names of those commemorated include: Heinrich Albers-Schönberg (1865–1921) Gustav Baer (1865–1925) Frederick Henry Baetjer (1874–1933) Burton Eugene Baker (1871–1913) Leonhard Baumeister (1874–1953) Eugen Beaujard (1874–1937) Jean Bergonié (1857–1925) Elis Berven (1885–1966) Reginald Blackall (-1925) Barry Blacken Joseph Boine (1883–1935) Percy Brown (?–1950) William Ironside Bruce (1879–1921) Eugene Wilson


id: shoji-nishikawa-20260505-0
file: data/en.wikipedia.org/wiki/Shoji_Nishikawa-0.md
category: reference
title: Shoji Nishikawa
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Shoji_Nishikawa
date_saved: 2026-05-05T11:00:08.235877+00:00
instance: kb-cron
parent: shoji-nishikawa-20260505-0
summary:
Shōji Nishikawa (Japanese: 西川 正治, Nishikawa Shōji, 5 December 1884 – 5 January 1952) was a Japanese physicist and a founding father of crystallography in Japan. == Education and career == Nishikawa was born in 1884 in Hachiōji, Tokyo Prefecture, as the son of an important silk dealer. He grew up in Tokyo and later studied at the Faculty of Science at the Imperial University of Tokyo (now University of Tokyo). His PhD in physics was supervised by Suekichi Kinoshita, with an initial focus on radioactivity. During this time, Nishikawa was inspired by Torahiko Terada to turn his interest turned to crystallography, which was experiencing a worldwide boom with the then new method of X-ray diffraction for structural analysis. The first publications of Nishikawa came out between 1913 and 1915, at a time when the British Nobel Prize winners in physics William Henry Bragg and William Lawrence Bragg were doing groundbreaking pioneering work in this field. Between 1916 and 1919, Nishikawa stayed in the United States and worked at Cornell University, where he was a mentor of the then graduate student Ralph Wyckoff. Before returning to Japan in 1920, Nishikawa also spent six months with William H. Bragg at University


id: george-alexander-pirie-20260505-0
file: data/en.wikipedia.org/wiki/George_Alexander_Pirie-0.md
category: reference
title: George Alexander Pirie
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/George_Alexander_Pirie
date_saved: 2026-05-05T11:00:09.420464+00:00
instance: kb-cron
parent: george-alexander-pirie-20260505-0
summary:
George Alexander Pirie (1863 – 27 October 1929) was a Scottish medical doctor and pioneering researcher in the use of X-rays in clinical medicine. == Early life == George Alexander Pirie was born in Dundee where his father, Dr George Clark Pirie, was a physician at the Dundee Royal Infirmary from 1862 to 1881. The family lived at 43 South Tay Street in Dundee. Pirie graduated with an MA from the University of St. Andrews, and then studied medicine at the University of Edinburgh, graduating with an MB ChM with first-class honours in 1886 and an MD in 1890. == Career == In 1887 he started work at Edinburgh Royal Infirmary as a resident under Scottish physician Sir Thomas Grainger Stewart, before moving to Dundee. Pirie worked at the Dundee Royal Infirmary from 1896 to 1925, and was an early pioneer in the application of X-rays to clinical medicine. He began experimenting with radiology, radiography, and X-rays in 1896, soon after the Wilhelm Röntgen had first demonstrated X-rays and their potential in Germany. Pirie established the first Electrical Department at Dundee Royal Infirmary in 1896. The Tayside Medical History Museum at the University of Dundee holds a number of examples


id: ivan-puluj-20260505-0
file: data/en.wikipedia.org/wiki/Ivan_Puluj-0.md
category: reference
title: Ivan Puluj
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ivan_Puluj
date_saved: 2026-05-05T11:00:10.655208+00:00
instance: kb-cron
parent: ivan-puluj-20260505-0
summary:
Ivan Pavlovych Puluj (Ukrainian: Іван Павлович Пулюй, pronounced [iˈwɑn pʊˈlʲuj]; German: Johann Puluj; 2 February 1845 – 31 January 1918) was a Ukrainian physicist and inventor known for his early research into X-rays. His contributions were largely neglected until the end of the 20th century. == Biography == Puluj was born on 2 February 1845 in Hrymailiv, which was then part of the Kingdom of Galicia and Lodomeria in the Austrian Empire. He was the son of Pavlo Puluj and Xenia née Burshtynska (Ukrainian: син Павла́ Пулю́я i Ксенiї ур. Бурштинської). The family's original surname was Pulguy until 1861. His father, Pavlo, was a landowner who served as burgomaster of Hrymayliv from 1861 to 1865. Ivan grew up in Hrymayliv, and attended primary school in the village. He then attended the gymnasium at Ternopil, where he became a co-founder and active member of the Ukrainian student society Hromada. He graduated with honors from Theological Faculty of the University of Vienna (1869), later also from the Department of Philosophy (1872). During his time there, he was the co-founder and later head of the Sich movement. After graduating, he worked as an assistant to the University of Vienna's experimental physics department. In


id: john-ramsay-surgeon-20260505-0
file: data/en.wikipedia.org/wiki/John_Ramsay_(surgeon)-0.md
category: reference
title: John Ramsay (surgeon)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/John_Ramsay_(surgeon)
date_saved: 2026-05-05T11:00:11.823671+00:00
instance: kb-cron
parent: john-ramsay-surgeon-20260505-0
summary:
Sir John Ramsay CBE FRACS (26 December 1872 – 6 February 1944) was an Australian surgeon, known for his association with the Launceston General Hospital. == Early life and education == Born in Glasgow, Scotland, on 26 December 1872, John Ramsay was the fourth son of the businessman John Ramsay and his wife, Margaret Thomson. The family migrated to Melbourne in 1878, where John Jr Ramsay attended State School No. 2855 at Prahran and Wesley College. He graduated as a Bachelor of Medicine and Surgery (M.B., B.S.) from the University of Melbourne with the Beaney Prize in pathology, in 1893. == Career == After a year's residency at the Royal Melbourne Hospital (1894), Ramsay spent the next year abroad in Auckland as a resident (1895), before being appointed house surgeon at the Launceston General Hospital. In 1896, Ramsay and Dr. Francis John Drake participated in the first demonstration of X-rays by Frank Styant Browne at Launceston General Hospital. In 1898, he became the surgeon-superintendent of the hospital. Graduating with a Master of Surgery degree from the University of Melbourne in 1902, Ramsay published 24 papers, including a discussion of his treatment of hydatid disease, as well as lecturing in Australia


id: henry-jasper-redfern-20260505-0
file: data/en.wikipedia.org/wiki/Henry_Jasper_Redfern-0.md
category: reference
title: Henry Jasper Redfern
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Henry_Jasper_Redfern
date_saved: 2026-05-05T11:00:13.031423+00:00
instance: kb-cron
parent: henry-jasper-redfern-20260505-0
summary:
Henry Jasper Redfern, FSMC, BOA, (1871–1928), or Jasper Redfern was a British optician, photographer, exhibitor, filmmaker, proprietor of photographic and lantern retail business, cinema pioneer and x-ray and radiographic pioneer. The business card of Redfern stated: H. Jasper Redfern, Practical Optician and Scientist, 55 & 57 Surrey Street, Sheffield. == Life and times == In 1871, Redfern was born at Sheffield, Yorkshire (West Riding), England. His parents were Walter Shepherd Redfern, age 31 (born at Sheffield, Yorkshire, England) and Sarah Rosebella Redfern, age 35 (born at Waddingham, Lincolnshire, England). In 1881, he was a resident at 40 Nicholson Road in Heeley, Sheffield, Yorkshire (West Riding), England. Redfern had one sister, Amy Eliza Redfern, age 11 and one brother, John William Redfern, age 7. In 1891, he lived with his parents and brother at 110 Pancras Square in St Pancras, London, England. His occupation was recorded as a photographer's apprentice. In 1894, he resided at 22 Stratford place in the Borough of Saint Pancras, East division, London, England. Redfern lived in a room he rented, the "front room on top floor, unfurnished" with rent of 11 shillings per week, with partial board, and rent paid to Mrs. Redfern at the same


id: henry-jasper-redfern-20260505-1
file: data/en.wikipedia.org/wiki/Henry_Jasper_Redfern-1.md
category: reference
title: Henry Jasper Redfern
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Henry_Jasper_Redfern
date_saved: 2026-05-05T11:00:13.031423+00:00
instance: kb-cron
parent: henry-jasper-redfern-20260505-0
summary:
=== Fred Holmes === In 1894, Redfern teamed with Fred Holmes as manager. Holmes developed skills as photographer, animated picture operator and projectionist. In September 1896, Redfern presented at the YMCA in Sheffield, a double-bill of film and x-ray demonstrations with a Kineopticon, a projector he obtained from Birt Acres. The Kineopticon had recently been patented by Acres on 27 May 1895 and quickly became popular. Redfern was keen to capitalise of this new invention and took advantage of the public's interest and fascination with these new animated or moving pictures. In 1898, Redfern secured an exclusive contract in England for the right to tour the groundbreaking, first feature film of the Corbett-Fitzsimmons boxing match of 1897. Redfern also secured or produced himself, films of local sporting events, and this proved to be a move towards making the headline feature as an event all by itself. He had the foresight to realise that a satisfied audience would return for future events and become loyal customers and customers that would return week after week. Redfern discovered a new market for the new medium of animated or motion pictures. He found new captive audiences and offered an afternoon's or evening's entertainment to


id: henry-jasper-redfern-20260505-2
file: data/en.wikipedia.org/wiki/Henry_Jasper_Redfern-2.md
category: reference
title: Henry Jasper Redfern
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Henry_Jasper_Redfern
date_saved: 2026-05-05T11:00:13.031423+00:00
instance: kb-cron
parent: henry-jasper-redfern-20260505-0
summary:
=== Royal Visits === On 21 May 1897, Redfern recorded events during Queen Victoria's visit, including the decorations on Pinstone Street taken at Sheffield City Centre. The original photograph was a stereo pair. During Queen Victoria's visit, he captured the decorations in Barker's Pool taken at Sheffield City Centre. The original photograph was a stereo pair. On 12 July 1905, Redfern photographed the Royal Visit of King Edward VII and Queen Alexandra, with one picture captured the Royal Couple leaving the Town Hall at Sheffield City Centre. Royal Visit of King Edward VII and Queen Alexandra, Their Majesties arriving at the Town Hall and meeting the Lord Mayor of Sheffield at Sheffield City Centre. On 26 April 1909, Redfern photographed the Royal Visit of the Prince and Princess of Wales, who later became George V and Queen Mary outside the Town Hall at Sheffield City Centre. The Prince and Princess of Wales (later George V) made a Royal Visit at Sheffield to open the Edgar Allen Library at Sheffield University. === Parks and places === In 1897, Redfern took an early photograph of Endcliffe Park taken at Endcliffe in Sheffield. Meersbrook Park at Meersbrook in Sheffield in 1897. In 1897,


id: henry-jasper-redfern-20260505-3
file: data/en.wikipedia.org/wiki/Henry_Jasper_Redfern-3.md
category: reference
title: Henry Jasper Redfern
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Henry_Jasper_Redfern
date_saved: 2026-05-05T11:00:13.031423+00:00
instance: kb-cron
parent: henry-jasper-redfern-20260505-0
summary:
=== 1901 === 7 February 1901, Sheffield Empire Theatre of Varieties; Jasper Redfern's Animated Pictures, and other acts 5 March 1901, Castlefold's Market Employees' Eighth Annual Tea & Concert; H. Jasper Redfern's Animated Pictures, and other acts 19 October 1901, Young Men's Christian Association, Sheffield; Programme of the President's 'At Home' Cinematograph by Mr Jasper Redfern 19 October 1901, Joseph Pickering & Sons, Limited, Sheffield. Employees'; Mr Redfern's, Cinematograph, and other acts 26 November 1901, Sheffield and District Press Club; Programme for Sat 23 November 1901; Arthur Dawes – Vocalist, J. A. Rodgers – Vocalist, J. B. Slack – Vocalist, Harry Heath – Vocalist, Maurice Taylor – cello, Mr Hinchcliffe – violin, Messrs A. Bagshaw, Taylor and Hinchcliffe; Mr H. Jasper Redfern – cinematograph exhibition === 1902 === 18 August 1902, New Palace Theatre, Hull; Programme for Monday, 18 August 1902; Alice Cooke – transformation dancer; The Maisanos – Continental Musical Grotesques; Sybil St. Elmo – Ballad Vocalist; Ross and Grayson – Comedy Act; Edwin Boyde – comedian; Redfern's Pictures, The Coronation of King Edward VII; Millie Hylton, James O'Connor and Charles Brady – Knockabout Comedians; Little Gitana – child vocalist; Sisters Morgan Duettists and Dancers; Glenroy Troupe – Male


id: reynolds-and-branson-20260505-0
file: data/en.wikipedia.org/wiki/Reynolds_and_Branson-0.md
category: reference
title: Reynolds and Branson
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reynolds_and_Branson
date_saved: 2026-05-05T11:00:14.297450+00:00
instance: kb-cron
parent: reynolds-and-branson-20260505-0
summary:
Reynolds & Branson Leeds was a business based at 13 Briggate and 14 Commercial Street in Leeds, England. The business lasted from 1816 (1816) to 1972 (1972). Edward Matterson managed the company in 1822, and William West F.R.S. took over in 1833. The National Archives Records about the company include a day book, sales ledger, and prescription books. The records were created by Reynolds & Branson Ltd. Reynolds & Branson was registered in July 1898 as a limited corporation with a capital of £34,000 in shares of £10 each by Messrs. R. Reynolds, F. W. Branson. No remuneration was given to Mr. R. Reynolds, but a £700 per annum was given to each of the others. In 1890, Richard Reynold's son, Richard Freshfield (Fred) Reynolds was made a partner. The firm was in the business of wholesale and retail for chemists and surgical instrument makers. == Origins == The original company can be traced back to 1816 (see Grace's Guide which is the leading source of historical information on industry and manufacturing in Britain). Edward Matterson was a druggist who ran the firm after being employed by Allen and Hanburys. He was educated at Leeds Grammar School. In 1822 the


id: reynolds-and-branson-20260505-1
file: data/en.wikipedia.org/wiki/Reynolds_and_Branson-1.md
category: reference
title: Reynolds and Branson
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reynolds_and_Branson
date_saved: 2026-05-05T11:00:14.297450+00:00
instance: kb-cron
parent: reynolds-and-branson-20260505-0
summary:
== The war years == During the First World War, he actively pursued efforts to standardize the size and shape of chemical glassware. In 1916, he was elected as an inaugural member of the Society of Glass Technology. He organized research and published works on these topics. Branson sought to secure in Great Britain the manufacturing process for the glass required for the equipment of munition factories.[8][9] Branson contributed a paper on the composition of some types of chemical glassware to the Society of Chemical Industry (J. SOC. Chem. Ind., 1915, 34, 471) in collaboration with his son Frederick Hartridge, a paper to the Transactions of the Society of Glass Technology (1919, 3, 249) "A proposed standard formula for a glass for lamp workers". Branson was chairman until retirement in 1932. His son, Frederick Hartridge, Associate of the Royal Institute of Chemistry AIC, became chairman and managing director of Reynolds & Branson.[5][7] he run the company for 20 years, until his untimely death on 10 February 1952, Frederick Hartridge had appointed his 3 Sons and Daughter as directors of Reynolds & Branson, Frederick Norman the eldest son who attended Ilkley Grammar an all-boys school, Eileen his only daughter, Peter Orchard


id: reynolds-and-branson-20260505-2
file: data/en.wikipedia.org/wiki/Reynolds_and_Branson-2.md
category: reference
title: Reynolds and Branson
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reynolds_and_Branson
date_saved: 2026-05-05T11:00:14.297450+00:00
instance: kb-cron
parent: reynolds-and-branson-20260505-0
summary:
Reynolds and Branson, 1887. Handy Guide to Surgical Instruments and Appliances etc. Reynolds and Branson, 14 Commercial Street, Leeds. Gloucester: John Bellows. 1887. 246p. Reynolds and Branson, 1890. Illustrated Catalogue of Chemical and Physical Apparatus, Pure Chemicals and Reagents. Reynolds and Branson, 14 Commercial Street, Leeds. 1890. 200p. Reynolds and Branson, 1903. Catalogue of Special Preparations. Reynolds and Branson, 14 Commercial Street, Leeds. 1903. 64p. Reynolds and Branson, 1907. Illustrated Catalogue of Optical Lanterns, Slides, Compressed Gases and Accessory Apparatus. Reynolds and Branson, 14 Commercial Street, Leeds. Leeds: McCorquodale & Co. 1907. 204p. Reynolds and Branson, 1908. Illustrated Catalogue of Surgical Instruments and Appliances. Reynolds and Branson, 14 Commercial Street, Leeds. Leeds: Chorley & Pickersgill. 1908. 119p. Reynolds and Branson, 1912. Catalogue of Special Preparations, Surgical Instruments, Trusses etc. Reynolds and Branson, 14 Commercial Street, Leeds. 1912. 84p. Reynolds and Branson, 1912–1920. Catalogue of Laboratory Fittings and Furniture. Reynolds and Branson. 1912–1920. 29p. == Reynolds & Branson Patents == Patents include: #1120 in 1885, #16373 in 1893, #14102 in 1899. Improvements in photographic ‘shutters’ for instantaneous photography. #1650. 1883. Means or apparatus for measuring quantities of highly volatile liquids. No. 3490. 1904. == References == == External links == Reynolds


id: richard-reynolds-chemist-20260505-0
file: data/en.wikipedia.org/wiki/Richard_Reynolds_(chemist)-0.md
category: reference
title: Richard Reynolds (chemist)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Richard_Reynolds_(chemist)
date_saved: 2026-05-05T11:00:15.469000+00:00
instance: kb-cron
parent: richard-reynolds-chemist-20260505-0
summary:
Richard Reynolds, FCS (12 May 1829 – 5 April 1900), was an English pharmaceutical chemist, optician, instrument maker, and X-ray pioneer. == Life and times == Reynolds came from a long line of Quakers, being a descendant of John Gurney. On 12 May 1829, he was born at Banbury, Oxford, England. His father Richard Freshfield Reynolds was an apothecary, known as the druggist of Banbury. His mother was Maria Reynolds, née Bassett. In 1843, Reynolds left school and became apprenticed to James Deane, chemist at Clapham Common. In 1844, he went to Leeds and apprenticed to the chemist Thomas Harvey. During the years 1850 to 1851, he attended the London School of Pharmacy and took first prizes for the examinations held by the Pharmaceutical Society in chemistry, materia medica (medical material/substance) and botany. At this time, T. B. Groves, Henry T. Watts, Dr. William Squire and other notable individuals were at "The Square". The Pharmaceutical Society was located on "The Square". Reynolds returned to Clapham and worked for two years with the chemist James Deane. During the time at Clapham, he took an interest in the analysis of native samples of carbonate of soda. In 1854, Reynolds returned to Leeds


id: wilhelm-r-ntgen-20260505-0
file: data/en.wikipedia.org/wiki/Wilhelm_Röntgen-0.md
category: reference
title: Wilhelm Röntgen
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wilhelm_Röntgen
date_saved: 2026-05-05T11:00:16.715879+00:00
instance: kb-cron
parent: wilhelm-r-ntgen-20260505-0
summary:
Wilhelm Conrad Röntgen (27 March 1845 – 10 February 1923) was a German experimental physicist who produced and detected electromagnetic radiation in a wavelength range known as X-rays (known as "Röntgen rays" in many languages). In 1901, Röntgen became the first recipient of the Nobel Prize in Physics "in recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him." The element roentgenium is named in his honor. == Biography == === Early life and education === Wilhelm Conrad Röntgen was born on 27 March 1845 in Lennep (now part of Remscheid), Prussia, the only child of Friedrich Conrad Röntgen, a merchant and cloth manufacturer, and Charlotte Constanze Frowein. In 1848, he moved with his parents to the Netherlands—where his mother's family lived—rendering him stateless. In 1862, Röntgen enrolled at Utrecht Technical School, where he followed courses for almost two years. In 1865, he was unfairly expelled from the Technical School when he was falsely accused of drawing a caricature of one of the teachers, which was actually drawn by someone else. Without a high school diploma, Röntgen could only attend university in the Netherlands as a visitor. In 1865, he tried


id: wilhelm-r-ntgen-20260505-1
file: data/en.wikipedia.org/wiki/Wilhelm_Röntgen-1.md
category: reference
title: Wilhelm Röntgen
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wilhelm_Röntgen
date_saved: 2026-05-05T11:00:16.715879+00:00
instance: kb-cron
parent: wilhelm-r-ntgen-20260505-0
summary:
In 1895, in his laboratory at the Physical Institute of the University of Würzburg, Röntgen was investigating the external effects of passing an electric discharge through various types of vacuum tube equipment—apparatuses from Heinrich Hertz, Johann Hittorf, William Crookes, Nikola Tesla, and Philipp Lenard. In early November, he was repeating an experiment with one of Lenard's tubes in which a thin aluminium window had been added to permit the cathode rays to exit the tube but a cardboard covering was added to protect the aluminium from damage by the strong electrostatic field that produces the cathode rays. He knew that the cardboard covering prevented light from escaping, yet he observed that the invisible cathode rays caused a fluorescent effect on a small cardboard screen painted with barium platinocyanide when it was placed close to the aluminium window. It occurred to Röntgen that the Crookes–Hittorf tube, which had a much thicker glass wall than the Lenard tube, might also cause this fluorescent effect. In the late afternoon of 8 November 1895, Röntgen was determined to test his idea. He carefully constructed a black cardboard covering similar to the one he had used on the Lenard tube. He covered the Crookes–Hittorf tube


id: wilhelm-r-ntgen-20260505-2
file: data/en.wikipedia.org/wiki/Wilhelm_Röntgen-2.md
category: reference
title: Wilhelm Röntgen
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wilhelm_Röntgen
date_saved: 2026-05-05T11:00:16.715879+00:00
instance: kb-cron
parent: wilhelm-r-ntgen-20260505-0
summary:
In November 2004, the IUPAC named element number 111 roentgenium (Rg) in his honor. The IUPAP adopted the name in November 2011. A collection of Röntgen's papers is held at the National Library of Medicine in Bethesda, Maryland. Today, in Remscheid-Lennep, 40 kilometres east of Röntgen's birthplace in Düsseldorf, is the Deutsches Röntgen-Museum. In Würzburg, where Röntgen discovered X-rays, a non-profit organization maintains his laboratory and provides guided tours to the Röntgen Memorial Site. World Radiography Day is an annual event promoting the role of medical imaging in modern healthcare. It is celebrated on 8 November each year, coinciding with the anniversary of Röntgen's discovery. It was first introduced in 2012 as a joint initiative between the European Society of Radiology, the Radiological Society of North America, and the American College of Radiology. As of 2023, 55 stamps from 40 countries have been issued commemorating Röntgen as the discoverer of X-rays. Röntgen Peak in Antarctica is named after Wilhelm Röntgen. Minor planet 6401 Roentgen is named after him. In 2010, Röntgen's discovery was honored in a Google doodle. == See also == German inventors and discoverers Röntgen Memorial Site Ivan Puluj == Notes == == References == == External links


id: karl-friedrich-schall-20260505-0
file: data/en.wikipedia.org/wiki/Karl_Friedrich_Schall-0.md
category: reference
title: Karl Friedrich Schall
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Karl_Friedrich_Schall
date_saved: 2026-05-05T11:00:17.931644+00:00
instance: kb-cron
parent: karl-friedrich-schall-20260505-0
summary:
Karl Friedrich Schall (16 March 1859 – 19 September 1925) was a German precision engineer and co-founder of the company Reiniger, Gebbert & Schall (RGS) in Erlangen. RGS was a manufacturer and supplier of durable medical equipment and a pioneer in the supply of x-ray equipment worldwide with offices in Berlin, Wien, London, Paris, Rome, Chicago and Sydney. == Life and times == Schall was born in 1859 at Öhringen in the Kingdom of Württemberg as the son of the lawyer William Schall. From 1877 to 1879, he was in Tübingen as a university mechanic and apprenticed as a precision mechanic. During 1880–1881, Schall completed the mandatory one-year volunteer service in the military, and travelled to Paris, London and Switzerland. On 24 January 1887, at Dresden he married Johanna Schmidlin (born 18 October 1859 in Giessbach – died June 1934 in Oberhofen). The couple had three children: Wilhelm, later called William (21 April 1888 – 2 December 1965), Mary Jane (27 May 1889 – October 1927) and Margarete (25 December 1890 – 21 March 1937). In 1893, Schall became a British citizen. == Reiniger, Gebbert and Schall == In 1883, Schall returned to Stuttgart, and opened his own workshop for


id: frank-k-schmidlin-20260505-0
file: data/en.wikipedia.org/wiki/Frank_K._Schmidlin-0.md
category: reference
title: Frank K. Schmidlin
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Frank_K._Schmidlin
date_saved: 2026-05-05T11:00:19.091572+00:00
instance: kb-cron
parent: frank-k-schmidlin-20260505-0
summary:
Frank K. Schmidlin (1861-1939) was an Australian X-ray pioneer, that was among the first to utilize the new technology of x-rays for medical applications. In Australia, the medical men of the day took a slow approach in the adoption of the new science that involved x-rays. Many of the early demonstrations were made by investigators outside the medical field. Upon examination of the initial investigators, several key factors were common. The individuals had already either been experimenting along similar lines to Wilhelm Röntgen with Crookes tubes and such, the physicists or scientists, or were actively associated with electrical work, the electricians, which made them particularly receptive to the technical appeal of the new science of x-rays. Records of the events reveal that among the medical men who witnessed the first images produced as radiographs, a rather small number had any great desire to employ X-rays directly in their own medical practice. After the early investigative work of Thomas Ranken Lyle, William Henry Bragg, Joseph Patrick Slattery, and others, almost all medical men were satisfied with soliciting the services of the external X-ray man when necessity arose for skiagraphs to be produced. As the utilization of x-rays became more acceptable, the


id: joseph-patrick-slattery-20260505-0
file: data/en.wikipedia.org/wiki/Joseph_Patrick_Slattery-0.md
category: reference
title: Joseph Patrick Slattery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Joseph_Patrick_Slattery
date_saved: 2026-05-05T11:00:20.272397+00:00
instance: kb-cron
parent: joseph-patrick-slattery-20260505-0
summary:
Joseph Patrick Slattery, CM (21 May 1866 – 31 March 1931) was an Irish-born physicist, radiologist, Catholic priest, pioneer in the field of radiography in Australia and credited with the first use of fluoroscopy in Australia. Born in 1866 in Waterford, Ireland, he traveled to Australia as a deacon in 1888, where he was ordained a priest by Cardinal Moran. As a member of the Vincentian Congregation, he and several of his confreres took over the running of St Stanislaus' at Bathurst from the diocesan clergy. Appointed to the position of professor and taught science, including physics and chemistry. Slattery had a keen interest in the new technology of wireless radio and was the first to install a wireless set west of the Blue Mountains. He was an early pioneer of radio in Australia and found delight in building radio sets. Slattery built an X-ray practice at Bathurst and local doctors benefited greatly from this convenience. He performed mission work for the Vincentian fathers and toured Australia and New Zealand to serve the faithful. Slattery was superior of the Vincentian novitiate at Eastwood. He was appointed vice-rector of St. John's College at the University of Sydney. At Springwood and Manly,


id: john-w-l-spence-20260505-0
file: data/en.wikipedia.org/wiki/John_W._L._Spence-0.md
category: reference
title: John W. L. Spence
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/John_W._L._Spence
date_saved: 2026-05-05T11:00:21.436509+00:00
instance: kb-cron
parent: john-w-l-spence-20260505-0
summary:
John Webster Lowson Spence MD LRCP LRCS (11 August 1870 – 15 March 1930) was a Scottish x-ray pioneer and an early victim of radiation poisoning. His name is one of 14 British professionals listed on the Monument to the X-ray and Radium Martyrs of All Nations, which was erected in 1936. In the words of his gravestone: he died that others might live. == Life == He was born in Smyrna in the Ottoman Empire on 11 August 1870 the son of Rev David Brown Spence, a Church of Scotland missionary. He was educated at the Royal High School in Edinburgh. He studied medicine at the University of Edinburgh, and from 1897 studied radiology under, or in correspondence with, Wilhelm Röntgen. He received his doctorate (MD) in 1898. Around 1903 he came to Edinburgh to assist Dawson Turner and William Hope Fowler in their experiments on radiology. In 1907 he became the only radiologist at the Edinburgh Sick Children's Hospital in Sciennes. He was widely respected for his work and kindness. It was common for early radiology pioneers to self-experiment, most commonly on their left arm as the majority of doctors were right-handed. Around 1910 he had several radiation-induced


id: joseph-william-sutton-20260505-0
file: data/en.wikipedia.org/wiki/Joseph_William_Sutton-0.md
category: reference
title: Joseph William Sutton
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Joseph_William_Sutton
date_saved: 2026-05-05T11:00:22.629884+00:00
instance: kb-cron
parent: joseph-william-sutton-20260505-0
summary:
Joseph William Sutton (21 October 1844 – 21 February 1914), identified in the print media as J. W. Sutton, was an Australian engineer, shipbuilder, inventor, pioneer in electric lighting and x-ray pioneer in Queensland. == Life and times == In 1844, Sutton was born in Stepney, London, England. His parents were George Sutton (Shipwright) and Elizabeth Kemmesat. He was christened on 1 December 1844. After Elizabeth's death, the George Sutton with three of his children (Hannah, Henry and Joseph) moved from London and arrived in Sydney 15 October 1852 on board the "Coldstream". (A year later Hannah and Henry were married in the same service 22 December 1853, to Daniel McLauchlan and Jemima Evans respectively at Christ Church St Laurence). Joseph married Mary Hurley (15 September 1847 – 11 July 1926) on 21 October 1869 in Balmain, Sydney. They lived for many years in "Stonehenge" on Bowen Terrace, overlooking the foundry on Kangaroo point. The couple built a home, Hurlton (a name derived from their surnames Hurley and Sutton) in Laurel Avenue, Chelmer in Brisbane. After the death of his widow, Hurlton was purchased in 1928 by William Robert Black, a philanthropist who donated it to the Presbyterian Church for


id: joseph-william-sutton-20260505-1
file: data/en.wikipedia.org/wiki/Joseph_William_Sutton-1.md
category: reference
title: Joseph William Sutton
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Joseph_William_Sutton
date_saved: 2026-05-05T11:00:22.629884+00:00
instance: kb-cron
parent: joseph-william-sutton-20260505-0
summary:
== Kitson Lighting and Heating Company Limited == Joseph William Sutton was a manager and consultant engineer. At the end of 1902 Sutton took an extensive trip to Europe and America for the Kitson Light Co. An article on this trip was written in the Brisbane Courier 17 Jan 1903 entitled "An Australian in England and America" From the Richmond River Express 17 Nov 1903: "On Saturday last Ald. Frost, who has been a consistent advocate for a trial of the Kitson light, for the purposes of, town lighting, was kept busy with the able electrical engineer, Mr. J. Sutton, who was sent from Brisbane by the Kitson Light Co. to instal the lamp at the intersection of Walker and Canterbury streets, in putting up the iron post and fixing the necessary machinery for the production of the light." == Electrical pioneer == On 9 December 1882, at Brisbane Queensland, the public was introduced to electricity by having a demonstration that utilized eight arc lights, erected along Queen Street. The lamps were erected on 20 foot cast iron standards. The power to supply these arc lights was taken from a 10 horsepower Crompton DC generator driven by a Robey steam


id: joseph-william-sutton-20260505-2
file: data/en.wikipedia.org/wiki/Joseph_William_Sutton-2.md
category: reference
title: Joseph William Sutton
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Joseph_William_Sutton
date_saved: 2026-05-05T11:00:22.629884+00:00
instance: kb-cron
parent: joseph-william-sutton-20260505-0
summary:
== Photographic pioneer == Joseph William Sutton was involved in the very beginning of the Queensland Photographic Society: From "The Week" newspaper Brisbane Sat 20 Sept 1884: "PHOTOGRAPHIC SOCIETY.—The newly formed Queensland photographers' society held a meeting on Monday in rooms over Sloss', confectioners, Queen-street. There was a good attendance of members. The following officers were elected for the ensuing year:—President, the Hon A. C. Gregory; vice-presidents, Professor Pepper, and Mr. J. W. Sutton; secretary, Mr. J. R. Hall; committee, Messrs. Rickardo, Lyons, and Service." From the beginning Sutton was often availing his steamers to be used to take members along the Brisbane river for photo shoots, as seen from The Brisbane Courier 17 Feb 1885: "The chairman (Sutton on this occasion) notified his intention of taking the members down the Bay, probably on Saturday next, for the purpose of giving them an opportunity to exhibit their skill in "snapping" pretty glimpses of river scenery." In these early days many of the society meetings were held at the Sutton household: Brisbane Courier 25 Jan 1886. "A MEETING of the Queensland Photographic Society was held on Saturday evening at Mr. J.W. Sutton's house. Mr. Sutton, who is vice-president, took the chair.....


id: joseph-william-sutton-20260505-3
file: data/en.wikipedia.org/wiki/Joseph_William_Sutton-3.md
category: reference
title: Joseph William Sutton
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Joseph_William_Sutton
date_saved: 2026-05-05T11:00:22.629884+00:00
instance: kb-cron
parent: joseph-william-sutton-20260505-0
summary:
== Sugar industry inventor == In 1878, Sutton developed a better method to extract sugar from sugar cane juice."What looks like a decided improvement upon the open air methods hitherto followed to evaporate cane juice has just been patented by Messrs. J. W. Sutton and Co., coppersmiths, Brisbane. Mr. Sutton aims at evaporating juice at a heat of from 120° to 180°. This he does in the open air. He obtains the required temperature by means of a steam coil running around his evaporating pan, which is of the ordinary circular form. This heat will not boil the liquor, of course; that he accomplishes by menus of a perforated pipe or coil coming in at the bottom of the evaporating pan. Through this latter coil, a current of air is forced by a fan blast. The air may either be of atmospheric temperature, or it may be heated, as seems most desirable. In the event of heated air being forced into the liquor, or through it, the air is passed through furnaces in a series of pipes, by which means it becomes highly rarefied, and the temperature is raised at the same time. We have seen the apparatus at work,


id: joseph-william-sutton-20260505-4
file: data/en.wikipedia.org/wiki/Joseph_William_Sutton-4.md
category: reference
title: Joseph William Sutton
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Joseph_William_Sutton
date_saved: 2026-05-05T11:00:22.629884+00:00
instance: kb-cron
parent: joseph-william-sutton-20260505-0
summary:
"Having thus explained the apparatus, Mr. Sutton made several exposures of plates with remarkably good results. One interesting exposure was a collection of various articles, offering various degrees of opacity to the rays. The development of the plates was admirably carried out by Mr. Ferguson under circumstances decidedly unfavourable to such delicate work, with capital results. The exhibition of articles on the fluorescent screen, where the wonderful effects of the X-rays were at once visible, called forth frequent applause. Coins placed in a cigar case were plainly seen, and so were similar articles placed between two-inch thick deal boards, or in the middle of a thick book. Neither the wood nor the paper seemed to offer much resistance to the light. The proceedings were terminated by a hearty vote of thanks to the lecturer and demonstrator." There are many references in the newspapers of the time of Sutton subsequently performing many demonstrations of these invisible rays using himself and other volunteers from his audiences. He later went on to also demonstrate the invisible rays of radium. == Ships built by J. W. Sutton and Company == The following is a partial list of ships built by J. W. Sutton and


id: joseph-william-sutton-20260505-5
file: data/en.wikipedia.org/wiki/Joseph_William_Sutton-5.md
category: reference
title: Joseph William Sutton
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Joseph_William_Sutton
date_saved: 2026-05-05T11:00:22.629884+00:00
instance: kb-cron
parent: joseph-william-sutton-20260505-0
summary:
1880, Essex, iron steamship, 79 gross tons. Length: 91', beam 18'6", draft: 6'3". Built as an unpowered lighter until circa 1888 (engine added) and in 1895 the boiler was added. In April 1903, first registered by William Collin & Sons Ltd, Brisbane. She serviced Maryborough, Queensland. 1882, Iceberg, iron screw steamer, 285 tons and 127 feet long. She was 289 gross registered tons, a refrigerated cargo steamship. 1883, Pearl Steamer for the Sandgate and Woody Point Ferry. See: https://www.flotilla-australia.com/qldothers.htm Archived 2 July 2018 at the Wayback Machine 1883, Mavis, paddle wheel steamer, 47 tons gross measurement, the first steamer to run to Bribie Island. Utilized to convey timber from the Coochin Sawmills to Brisbane, taking back general cargo and supplies for residents in the Bribie district. Built for James Campbell and Sons sawmill. 1883, Redcliffe, Steamer for the Redcliffe and Sandgate Steam Ferry Company. Built June 1883. 1883, Eucalypta, Steamer for Gilbert Burnett, of Cleveland, For carrying timber for his sawmill. Dimensions:— Length, 75 feet; beam, 16 feet and depth of hold, 5 feet. She was propelled by a stern-wheel 11 feet in diameter, driven by a pair of engines of 16 horse-power, fitted with a surface condenser. From "The


id: richard-threlfall-20260505-0
file: data/en.wikipedia.org/wiki/Richard_Threlfall-0.md
category: reference
title: Richard Threlfall
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Richard_Threlfall
date_saved: 2026-05-05T11:00:23.810450+00:00
instance: kb-cron
parent: richard-threlfall-20260505-0
summary:
Sir Richard Threlfall (14 August 1861 – 10 July 1932) was an English chemist and engineer, he established the School of Physics at the University of Sydney and made important contributions to military science during World War I. In 1899, he was elected a fellow of the Royal Society. In 1917, he was created KBE and then GBE in 1927. == Science and consulting career == After the discovery new waves by Heinrich Hertz, Threlfall suggested in a 1890 oral discussion that "Signaling, for instance, might be accomplished secretly by means of a sort of electric ray flasher", thus predicting yet-uninvented radio communications. In July 1915 he invented the 'Threlfallite' hand grenade, consisting of a cylindrical tin containing white phosphorus, paraffin, oil and petrol. Originally designed as an incendiary device to destroy long grass in front of the trenches that gave cover to enemy raiding parties, it also had a useful smoke-producing effect and was used at the Battle of Loos. == Death == Threlfall died on 10 July 1932 and is buried in a family tomb at St Anne's Church, Woodplumpton, Lancashire. He was survived by four sons and two daughters. He was the author of On Laboratory Arts.


id: dawson-turner-radiologist-20260505-0
file: data/en.wikipedia.org/wiki/Dawson_Turner_(radiologist)-0.md
category: reference
title: Dawson Turner (radiologist)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dawson_Turner_(radiologist)
date_saved: 2026-05-05T11:00:24.983568+00:00
instance: kb-cron
parent: dawson-turner-radiologist-20260505-0
summary:
Dawson Fyers Duckworth Turner, FRSE, FRCPE (1857–1928) was a British pioneer of radiology and patron of the arts, who died of radiation related cancer. == Early life == He was born in Liverpool in 1857 the son of Rev Dawson Turner and attended Shrewsbury School in Shropshire. He then studied at Dalhousie University in Nova Scotia, Canada where he graduated BA in 1884. Returning to Britain Turner studied at Edinburgh University where he graduated in medicine (MB CM with honours) in 1888 and attained his MD 1890. He became MRCPE in 1890 and was elected fellow (FRCPE) in 1891. == Early medical career == After serving as resident physician in the Royal Infirmary of Edinburgh under Sir James Affleck he was appointed Lecturer in Physics at the Edinburgh Extramural School of Medicine at Surgeons' Hall, Edinburgh. In addition he acted as clinical tutor in clinical medicine at the Extramural School at Surgeons' Hall. == Radiology career == When X-rays were discovered by Röntgen in 1895 Dawson Turner was one of the first to appreciate their possible application in medicine. He built an early X-ray apparatus in his home at 32 George Square, Edinburgh. On 5 February 1896 he demonstrated X-rays


id: w-watson-and-son-20260505-0
file: data/en.wikipedia.org/wiki/W._Watson_and_Son-0.md
category: reference
title: W. Watson and Son
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/W._Watson_and_Son
date_saved: 2026-05-05T11:00:26.236032+00:00
instance: kb-cron
parent: w-watson-and-son-20260505-0
summary:
W. Watson and Son was an optical instrument maker. In 1837, the William Watson business was established in London for the manufacture of optical instruments. By the 1840s, the company moved into lanterns, slides and associated equipment. In 1868, the name was changed to W. Watson & Son and by this time were located at 313 High Holborn, London. In the 1870s, the company added photographic equipment and became known as a leading manufacturer of the Highest Class Photographic Instruments and Apparatus in England. Into the 1940s, the company remained at 313 High Holborn. == W. Watson and Sons == On 9 January 1881 William Watson died. In 1883, the name of the company was changed to W. Watson & Sons as the son, Charles Henry Watson joined the business. The 1883 Kelly's Business Directory listed both Charles Henry Watson and Henry Watson as associated with the Watson & Sons company located at 23 Walton Street, Aylesbury, England. In 1889, the company participated in the formation of a Photographic Trades Section of the London Chamber of Commerce. In 1894, the company exhibited scientific instruments at the Antwerp Exhibition. In the 1890s, the business continued to grow and advertised in catalogues


id: william-webster-chemical-engineer-20260505-0
file: data/en.wikipedia.org/wiki/William_Webster_(chemical_engineer)-0.md
category: reference
title: William Webster (chemical engineer)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/William_Webster_(chemical_engineer)
date_saved: 2026-05-05T11:00:27.432026+00:00
instance: kb-cron
parent: william-webster-chemical-engineer-20260505-0
summary:
William Webster (1855–1910) was an English chemical engineer credited with developments in gas detection, sewage treatment and medical use of x-rays. A gifted artist and musician, Webster also helped found the Blackheath Concert Halls and the adjacent Conservatoire in Blackheath in south-east London during the 1890s. == Career == Webster was the son of William Webster, a successful building contractor who grew wealthy from constructing major civil engineering and building projects in London. The family lived from 1869 in Wyberton House in Lee Terrace, Blackheath. The younger William Webster trained as a chemical engineer. A fellow of the Chemical Society, he patented a system to detect hydrogenous gases in mines in 1876, and later developed a system for the electrolytic purification of sewage (patent application filed on 22 December 1887; US patent awarded on 19 February 1889), trialled in 1888 at the Crossness Southern Outfall works which had been built by his father's firm in the 1860s. Webster was also a pioneer in x-ray research and a founder member of the Röntgen Society (since 1927 part of the British Institute of Radiology), assisting surgeon Thomas Moore in producing radiographs in 1896, after which Moore set up an x-ray unit at


id: francis-henry-williams-20260505-0
file: data/en.wikipedia.org/wiki/Francis_Henry_Williams-0.md
category: reference
title: Francis Henry Williams
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Francis_Henry_Williams
date_saved: 2026-05-05T11:00:28.558960+00:00
instance: kb-cron
parent: francis-henry-williams-20260505-0
summary:
Francis Henry Williams (15 April 1852–22 June 1936) was an American medical doctor, a pioneer in the field of radiology. == Biography == Williams was born on 15 April 1852, in Uxbridge, Massachusetts. His father was Professor of Ophthalmology at Harvard Medical School. Williams graduated from Massachusetts Institute of Technology in 1873, at the age of twenty-one, then studied medicine at Harvard University, where he obtained his Doctorate in Medicine in 1877. He then spent two years studying in Europe before returning to Boston to practice as a physician. He was awarded the titles of Instructor in Materia Medica and Therapeutics and Assistant Professor of Therapeutics from Harvard Medical School. In 1892, he introduced bacterial examination to Boston City Hospital, and in 1894 was the first physician in the region to neutralize diphtheria with antitoxin. In 1895, Wilhelm Röntgen discovered X-rays ("Röntgen rays"); Williams lost no time in applying this innovation, beginning his use of fluoroscopy in 1896. Williams performed trials of Röntgen's experiments at the MIT laboratories, and conducted research on the diagnostic potential of X-rays for different conditions, including thoracic aneurysm, pericardial effusion, cardiac hypertrophy, pulmonary tuberculosis, and emphysema. He founded what would become the Department of Radiology


id: william-cleaver-woods-20260505-0
file: data/en.wikipedia.org/wiki/William_Cleaver_Woods-0.md
category: reference
title: William Cleaver Woods
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/William_Cleaver_Woods
date_saved: 2026-05-05T11:00:45.169879+00:00
instance: kb-cron
parent: william-cleaver-woods-20260505-0
summary:
William Cleaver Woods, M.B., Ch.M. Edinburgh, M.D. (25 April 1852 – 9 April 1943) was a physician, politician and pioneer of Australian medical science, specialising in X-rays for diagnostic applications and cancer treatments. == Life and times == In 1852, Woods was born in West Derby, Lancashire in England, the son of Richard Woods and Catherine née Cromwell. He was christened on 7 June 1852 in Liverpool, Lancashire, England. At the age of 10, the family moved to Melbourne in Australia and Woods grew up in Ballarat. Woods, a physician from Liverpool, England, married Margaret, née Grieve from New South Wales. The couple travelled to Europe aboard the R.M.S. Oceana for the honeymoon. The Woods had a large family with 9 sons and 2 daughters. The sons included Dr. L.S. Woods from Albury, Dr. John Grieve Woods, also known as the Flying Doctor of Broken Hill, Dr. R.G. Woods from Goulburn, G.C. Woods of Lockhart, and Norman Woods from Sydney. The daughters were Rice from Melbourne and Manning from Albury. Four other sons died prior to his death in 1943. Woods died in 1943 at Sydney, New South Wales, Australia. He was buried at Albury New Cemetery, North Albury, New


id: list-of-unsolved-problems-in-astronomy-20260505-0
file: data/en.wikipedia.org/wiki/List_of_unsolved_problems_in_astronomy-0.md
category: reference
title: List of unsolved problems in astronomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_astronomy
date_saved: 2026-05-05T11:00:46.788160+00:00
instance: kb-cron
parent: list-of-unsolved-problems-in-astronomy-20260505-0
summary:
This article is a list of notable unsolved problems in astronomy. Problems may be theoretical or experimental. Theoretical problems result from inability of current theories to explain observed phenomena or experimental results. Experimental problems result from inability to test or investigate a proposed theory. Other problems involve unique events or occurrences that have not repeated themselves with unclear causes. == Planetary astronomy == === The Solar System === Orbiting bodies and rotation: Are there any non-dwarf planets beyond Neptune? Why do extreme trans-Neptunian objects have elongated orbits? The rotation rate of Saturn: Why does the magnetosphere of Saturn rotate at a rate close to that at which the planet's clouds rotate? What is the rotation rate of Saturn's deep interior? Satellite geomorphology: What is the origin of the chain of high mountains that closely follows the equator of Saturn's moon, Iapetus? Are the mountains the remnant of hot and fast-rotating young Iapetus? Are the mountains the result of material (either from the rings of Saturn or its ring) that over time collected upon the surface? === Extra-solar === How common are Solar System-like planetary systems? (Some observed planetary systems contain Super-Earths and Hot Jupiters that orbit very close to their


id: list-of-unsolved-problems-in-astronomy-20260505-1
file: data/en.wikipedia.org/wiki/List_of_unsolved_problems_in_astronomy-1.md
category: reference
title: List of unsolved problems in astronomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_astronomy
date_saved: 2026-05-05T11:00:46.788160+00:00
instance: kb-cron
parent: list-of-unsolved-problems-in-astronomy-20260505-0
summary:
== Cosmology == Cosmological principle: Is the universe homogeneous and isotropic at sufficiently large scales, as claimed by the cosmological principle and assumed by all models that use the Friedmann–Lemaître–Robertson–Walker (FLRW) metric, including the current version of the ΛCDM model, or is the universe inhomogeneous or anisotropic? Is the CMB dipole purely kinematic, or does it signal anisotropy of the universe, resulting in the breakdown of the FLRW metric and the cosmological principle? Is the Hubble tension evidence that the cosmological principle is false? If the cosmological principle is correct, is the FLRW metric the correct metric describing the universe? Are the observations interpreted as the accelerating expansion of the universe correctly interpreted, or are they instead evidence that the cosmological principle is false? Copernican principle: Are cosmological observations made from Earth representative of observations from the other positions in the universe? Dark matter: What is the identity and composition of dark matter? Is dark matter a particle? If so, is it a WIMP, an axion, the lightest superpartner (LSP), or something else? Do the phenomena attributed to dark matter point to an extension of gravity instead of some other type of matter? Dark energy: What causes the observed accelerating


id: baldwin-effect-astronomy-20260505-0
file: data/en.wikipedia.org/wiki/Baldwin_effect_(astronomy)-0.md
category: reference
title: Baldwin effect (astronomy)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Baldwin_effect_(astronomy)
date_saved: 2026-05-05T11:00:47.961724+00:00
instance: kb-cron
parent: baldwin-effect-astronomy-20260505-0
summary:
The Baldwin effect in astronomy describes a relationship between continuum and emission-line fluxes observed in the electromagnetic spectra of quasars and active galactic nuclei, namely an anticorrelation between the equivalent width, Wλ, of a spectral line and the continuum luminosity, L, in broad UV optical emission lines. This means that the ratio of brightness of the emission line to the brightness of the nearby continuum decreases with increasing luminosity of the continuum. == Discovery and observations == The effect was discovered in observations of high-redshift quasars reported in 1977, and has been commonly named after the discoverer Jack Allen Baldwin, an astronomer at Lick Observatory. It was found that the equivalent width of the broad ultraviolet C IV (λ 1549) emission line, caused by the presence of thrice ionised carbon C3+, decreased with increasing continuum luminosity of the source. For flat-spectrum, radio-loud quasars the relation W λ ∝ L − 2 / 3 {\displaystyle W_{\lambda }\propto L^{-2/3}} was found. The same effect has been observed for other spectral lines such as the Ly-α hydrogen line and the C III] (λ 1909) line of twice ionised carbon. It has also been found for spectral lines in the infrared range, e.g. in


id: blc1-20260505-0
file: data/en.wikipedia.org/wiki/BLC1-0.md
category: reference
title: BLC1
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/BLC1
date_saved: 2026-05-05T11:00:49.157998+00:00
instance: kb-cron
parent: blc1-20260505-0
summary:
BLC1 (Breakthrough Listen Candidate 1) was a candidate SETI radio signal detected and observed during April and May 2019, and first reported on 18 December 2020, spatially coincident with the direction of the Solar System's closest neighboring star, Proxima Centauri. == Signal == The apparent shift in its frequency, consistent with the Doppler effect, was suggested to be inconsistent with what would be caused by the movement of Proxima b, a planet of Proxima Centauri. The Doppler shift in the signal was the opposite of what would be expected from the Earth's spin, in that the signal was observed to increase in frequency rather than decrease. Although the signal was detected by Parkes Radio Telescope during observations of Proxima Centauri, due to the beam angle of Parkes Radio telescope, the signal would be more accurately described as having come from within a circle roughly 16 arcminutes (approximately 1/4 of a degree, half the angular width of Earth's moon) in angular diameter, containing Proxima Centauri, so the signal could have originated elsewhere in the Alpha Centauri system. The signal had a frequency of 982.002 MHz. The radio signal was detected during 30 hours of observations conducted by Breakthrough Listen through the


id: dark-matter-20260505-0
file: data/en.wikipedia.org/wiki/Dark_matter-0.md
category: reference
title: Dark matter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark_matter
date_saved: 2026-05-05T11:00:51.613917+00:00
instance: kb-cron
parent: dark-matter-20260505-0
summary:
In astronomy and cosmology, dark matter is an invisible and hypothetical form of matter that does not interact with electromagnetic radiation, including light. Dark matter is implied by gravitational effects that cannot be explained by general relativity unless more matter is present than can be observed. Such effects occur in the context of formation and evolution of galaxies, gravitational lensing, the observable universe's current structure, mass position in galactic collisions, the motion of galaxies within galaxy clusters, and cosmic microwave background anisotropies. Dark matter is thought to serve as gravitational scaffolding for cosmic structures. After the Big Bang, dark matter clumped into blobs along narrow filaments with superclusters of galaxies forming a cosmic web at scales on which entire galaxies appear like tiny particles. In the standard Lambda-CDM model of cosmology, the mass–energy content of the universe is 5% ordinary matter, 26.8% dark matter, and 68.2% a form of energy known as dark energy. Thus, dark matter constitutes 85% of the total mass, while dark energy and dark matter constitute 95% of the total mass–energy content. While the density of dark matter is significant in the halo around a galaxy, its local density in the Solar System is much less


id: dark-matter-20260505-1
file: data/en.wikipedia.org/wiki/Dark_matter-1.md
category: reference
title: Dark matter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark_matter
date_saved: 2026-05-05T11:00:51.613917+00:00
instance: kb-cron
parent: dark-matter-20260505-0
summary:
=== 1970s === The hypothesis of dark matter largely took root in the 1970s. Several different observations were synthesized to argue that galaxies should be surrounded by halos of unseen matter. In two papers that appeared in 1974, this conclusion was drawn in tandem by independent groups: in Princeton, New Jersey, by Jeremiah Ostriker, Jim Peebles, and Amos Yahil, and in Tartu, Estonia, by Jaan Einasto, Enn Saar, and Ants Kaasik. One of the observations that served as evidence for the existence of galactic halos of dark matter was the shape of galaxy rotation curves. These observations were done in optical and radio astronomy. In optical astronomy, Vera Rubin and Kent Ford worked with a new spectrograph to measure the velocity curve of edge-on spiral galaxies with greater accuracy. At the same time, radio astronomers were making use of new radio telescopes to map the 21 cm line of atomic hydrogen in nearby galaxies. The radial distribution of interstellar atomic hydrogen (HI) often extends to much greater galactic distances than can be observed as collective starlight, expanding the sampled distances for rotation curves – and thus of the total mass distribution – to a new dynamical regime. Early mapping of


id: dark-matter-20260505-2
file: data/en.wikipedia.org/wiki/Dark_matter-2.md
category: reference
title: Dark matter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark_matter
date_saved: 2026-05-05T11:00:51.613917+00:00
instance: kb-cron
parent: dark-matter-20260505-0
summary:
In standard cosmological calculations, "matter" means any constituent of the universe whose energy density scales with the inverse cube of the scale factor, i.e., ρ ∝ a−3 . This is in contrast to "radiation", which scales as the inverse fourth power of the scale factor ρ ∝ a−4 , and a cosmological constant, which does not change with respect to a (ρ ∝ a0). The different scaling factors for matter and radiation are a consequence of radiation redshift. For example, after doubling the diameter of the observable Universe via cosmic expansion, the scale, a, has doubled. The energy of the cosmic microwave background radiation has been halved (because the wavelength of each photon has doubled); the energy of ultra-relativistic particles, such as early-era standard-model neutrinos, is similarly halved. The cosmological constant, as an intrinsic property of space, has a constant energy density regardless of the volume under consideration. In principle, "dark matter" means all components of the universe which are not visible but still obey ρ ∝ a−3 . In practice, the term "dark matter" is often used to mean only the non-baryonic component of dark matter, i.e., excluding "missing baryons". Context will usually indicate which meaning is intended. ==


id: dark-matter-20260505-3
file: data/en.wikipedia.org/wiki/Dark_matter-3.md
category: reference
title: Dark matter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark_matter
date_saved: 2026-05-05T11:00:51.613917+00:00
instance: kb-cron
parent: dark-matter-20260505-0
summary:
=== Gravitational lensing === One of the consequences of general relativity is the gravitational lens. Gravitational lensing occurs when massive objects between a source of light and the observer act as a lens to bend light from this source. Lensing does not depend on the properties of the mass; it only requires there to be a mass. The more massive an object, the more lensing is observed. An example is a cluster of galaxies lying between a more distant source such as a quasar and an observer. In this case, the galaxy cluster will lens the quasar. Strong lensing is the observed distortion of background galaxies into arcs when their light passes through such a gravitational lens. It has been observed around many distant clusters including Abell 1689. By measuring the distortion geometry, the mass of the intervening cluster can be obtained. In the weak regime, lensing does not distort background galaxies into arcs, causing minute distortions instead. By examining the apparent shear deformation of the adjacent background galaxies, the mean distribution of dark matter can be characterized. The measured mass-to-light ratios correspond to dark matter densities predicted by other large-scale structure measurements. === Type Ia supernova distance measurements ===


id: dark-matter-20260505-4
file: data/en.wikipedia.org/wiki/Dark_matter-4.md
category: reference
title: Dark matter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark_matter
date_saved: 2026-05-05T11:00:51.613917+00:00
instance: kb-cron
parent: dark-matter-20260505-0
summary:
Dark matter can be divided into cold, warm, and hot categories. These categories refer to velocity rather than an actual temperature, and indicate how far corresponding objects moved due to random motions in the early universe, before they slowed due to cosmic expansion. This distance is called the free streaming length. The categories of dark matter are set with respect to the size of the collection of mass prior to structure formation that later collapses to form a dwarf galaxy. This collection of mass is sometimes called a protogalaxy. Dark matter particles are classified as cold, warm, or hot if their free streaming length is much smaller (cold), similar to (warm), or much larger (hot) than the protogalaxy of a dwarf galaxy. Mixtures of the above are also possible: a theory of mixed dark matter was popular in the mid-1990s, but was rejected following the discovery of dark energy. The significance of the free streaming length is that the universe began with some primordial density fluctuations from the Big Bang (in turn arising from quantum fluctuations at the microscale). Particles from overdense regions will naturally spread to underdense regions, but because the universe is expanding quickly, there is a time


id: dark-matter-20260505-5
file: data/en.wikipedia.org/wiki/Dark_matter-5.md
category: reference
title: Dark matter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark_matter
date_saved: 2026-05-05T11:00:51.613917+00:00
instance: kb-cron
parent: dark-matter-20260505-0
summary:
There exists no formal definition of a Weakly Interacting Massive Particle (WIMP), but broadly, it is an elementary particle which interacts via gravity and any other force (or forces) which is as weak as or weaker than the weak nuclear force, but also non-vanishing in strength. Many WIMP candidates are expected to have been produced thermally in the early Universe, similarly to the particles of the Standard Model according to Big Bang cosmology, and usually will constitute cold dark matter. Obtaining the correct abundance of dark matter today via thermal production requires a self-annihilation cross section of ⟨ σ v ⟩ {\displaystyle \langle \sigma v\rangle } ≃ 3×10−26 cm3⋅s−1, which is roughly what is expected for a new particle in the 100 GeV/c2 mass range that interacts via the electroweak force. Because supersymmetric extensions of the Standard Model of particle physics readily predict a new particle with these properties, this apparent coincidence has been called the "WIMP miracle", and a stable supersymmetric partner has long been a prime explanation for dark matter. Experimental efforts to detect WIMPs include the search for products of WIMP annihilation, including gamma rays, neutrinos and cosmic rays in nearby galaxies and galaxy clusters; direct detection


id: dark-matter-20260505-6
file: data/en.wikipedia.org/wiki/Dark_matter-6.md
category: reference
title: Dark matter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark_matter
date_saved: 2026-05-05T11:00:51.613917+00:00
instance: kb-cron
parent: dark-matter-20260505-0
summary:
Primordial black holes (PBHs) are hypothetical black holes that formed soon after the Big Bang. In the inflationary era and early radiation-dominated universe, extremely dense pockets of subatomic matter may have been tightly packed to the point of gravitational collapse, creating black holes without the supernova compression typically needed to create stellar black holes. The idea was first suggested by Yakov Zeldovich and Igor Dmitriyevich Novikov in 1966, and independently by Stephen Hawking in 1971. Because PBHs would form prior to stellar evolution, they are non-baryonic dark matter candidates and are not limited to the narrow mass range of stellar black holes; they could range from Planck-mass relics to supermassive scales. Interest in PBHs as a primary component of dark matter was revived following the 2015 discovery of gravitational waves by LIGO. Their first detected merger involved black holes of approximately 30 solar masses; such objects are difficult to explain via standard stellar collapse but fit the predicted mass range for PBHs formed during the QCD transition in the early universe. This interest was bolstered in November 2025, when the LIGO/Virgo/KAGRA collaboration reported a candidate gravitational wave signal from a sub-solar mass merger. As no astrophysical process is known to


id: dark-matter-20260505-7
file: data/en.wikipedia.org/wiki/Dark_matter-7.md
category: reference
title: Dark matter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark_matter
date_saved: 2026-05-05T11:00:51.613917+00:00
instance: kb-cron
parent: dark-matter-20260505-0
summary:
Direct detection experiments aim to observe interactions between dark matter particles passing through the Earth and ordinary matter detector targets. For Weakly interacting massive particles (WIMPs), the primary signature is a low-energy recoil of nuclei (typically a few keV), which induces energy in the form of scintillation light, ionization, or phonons (heat). For axions, experiments typically search for the conversion of axions into photons within a strong magnetic field (the Primakoff effect). To detect these rare events effectively, it is crucial to maintain an extremely low background, which is why such experiments typically operate deep underground where interference from cosmic rays is minimized. Major underground laboratories hosting these experiments include SNOLAB (Canada), LNGS (Italy), CJPL (China), and the SURF (USA). ==== WIMPs ==== WIMP searches mostly use either cryogenic or noble liquid detector technologies. Cryogenic detectors, operating at temperatures below 100 mK, detect the heat produced when a particle hits an atom in a crystal absorber such as germanium. Experiments using this technology include SuperCDMS and EDELWEISS. Noble liquid detectors detect scintillation and ionization produced by a particle collision in liquid xenon or argon. This technology has led the field in sensitivity for the last decade. Major current experiments include


id: dark-matter-20260505-8
file: data/en.wikipedia.org/wiki/Dark_matter-8.md
category: reference
title: Dark matter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark_matter
date_saved: 2026-05-05T11:00:51.613917+00:00
instance: kb-cron
parent: dark-matter-20260505-0
summary:
Stellar heating: If dark matter particles capture inside dense stars like neutron stars or white dwarfs, they can deposit kinetic energy during the capture process or through subsequent annihilation. This mechanism, known as "dark kinetic heating", would maintain the star at a temperature higher than expected for its age, potentially arresting its cooling indefinitely. The observation of old, "cold" neutron stars therefore places stringent limits on the scattering cross-section of dark matter particles with nucleons, as any significant interaction would have kept these stars hotter than observed. Stellar cooling: New light particles, such as axions, could be produced in the hot cores of stars and escape freely, carrying away energy. This additional energy loss channel would alter the evolution of stars, cooling them faster than standard models predict. Comparisons of observed red giant branch tips and white dwarf cooling curves with theoretical models have set some of the strongest constraints on the coupling of axions to electrons and photons. Black hole superradiance: Ultralight bosons, such as axions or dark photons, can extract rotational energy from spinning black holes through a process called superradiance. If the boson's Compton wavelength is comparable to the black hole's event horizon size, the particles form


id: dark-matter-20260505-9
file: data/en.wikipedia.org/wiki/Dark_matter-9.md
category: reference
title: Dark matter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark_matter
date_saved: 2026-05-05T11:00:51.613917+00:00
instance: kb-cron
parent: dark-matter-20260505-0
summary:
=== Non-mainstream and less established particle, field, and structure theories === While WIMPs, axions, and primordial black holes remain the primary candidates for dark matter, numerous other theories have been proposed to address specific observational anomalies or theoretical motivations. These alternative models often explore mass ranges and interaction strengths outside the standard parameter space, ranging from ultra-light scalar fields to massive composite states. Some hypotheses posit the existence of complex "dark sectors" with their own fundamental forces, while others suggest that dark matter may be unstable, dynamical, or composed of mirror particles. The following list encompasses these less established but theoretically motivated candidates and frameworks. Chameleon particle – Hypothetical scalar particle that couples to matter more weakly than gravity Dark galaxy – Hypothesized galaxy with no, or very few, stars Dark radiation – Postulated type of radiation that mediates interactions of dark matter Density wave theory – A theory in which waves of compressed gas, which move slower than the galaxy, maintain galaxies' structure Dynamical dark matter Exotic matter – Physics term for multiple concepts Feebly interacting particles Light dark matter – Dark matter weakly interacting massive particles candidates with masses less than 1 GeV Mirror matter – Hypothetical counterpart


id: diffuse-extragalactic-background-radiation-20260505-0
file: data/en.wikipedia.org/wiki/Diffuse_extragalactic_background_radiation-0.md
category: reference
title: Diffuse extragalactic background radiation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Diffuse_extragalactic_background_radiation
date_saved: 2026-05-05T11:00:52.808378+00:00
instance: kb-cron
parent: diffuse-extragalactic-background-radiation-20260505-0
summary:
The diffuse extragalactic background radiation (DEBRA) refers to the photon field of extragalactic origin that fills our Universe. It contains photons whose energies span more than twenty orders of magnitude, from 10−7 eV to more than 100 GeV. This range covers everything from the microwaves emitted by free hydrogen atoms to ultra high-energy gamma rays, which can only be emitted by the most powerful physical processes in the modern universe such as kilonovas and merging black holes. The origin and the physical processes involved are different within every wavelength range. There is plenty of observational evidence that support the existence of the DEBRA. The figure shows a schematic picture, based on many different data sets, of the spectral intensity (also called spectral radiance) multiplied by wavelength of the DEBRA over all the electromagnetic spectrum. This representation is convenient because the area inside the curve is the energy. The nature and history of the universe is coded in this radiation field and any realistic cosmological model must be able to describe it. Understanding the DEBRA is a major challenge of modern cosmology with huge consequences in other fields of astrophysics, therefore extraordinary efforts are being put by theoreticians, observers, and instrumentalists


id: diffuse-interstellar-bands-20260505-0
file: data/en.wikipedia.org/wiki/Diffuse_interstellar_bands-0.md
category: reference
title: Diffuse interstellar bands
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Diffuse_interstellar_bands
date_saved: 2026-05-05T11:00:53.979505+00:00
instance: kb-cron
parent: diffuse-interstellar-bands-20260505-0
summary:
Diffuse interstellar bands (DIBs) are absorption features seen in the spectra of astronomical objects in the Milky Way and other galaxies. They are caused by the absorption of light by the interstellar medium. Circa 500 bands have now been seen, in ultraviolet, visible and infrared wavelengths. The origin of most DIBs remains unknown, with common suggestions being polycyclic aromatic hydrocarbons and other large carbon-bearing molecules. Only one DIB carrier has been identified: ionised buckminsterfullerene (C60+), which is responsible for several DIBs in the near-infrared. The carriers of most DIBs remain unidentified. == Discovery and history == Much astronomical work relies on the study of spectra - the light from astronomical objects dispersed using a prism or, more usually, a diffraction grating. A typical stellar spectrum will consist of a continuum, containing absorption lines, each of which is attributed to a particular atomic energy level transition in the atmosphere of the star. The appearances of all astronomical objects are affected by extinction, the absorption and scattering of photons by the interstellar medium. Relevant to DIBs is interstellar absorption, which predominantly affects the whole spectrum in a continuous way, rather than causing absorption lines. In 1922, though, astronomer Mary Lea Heger first


id: disrupted-planet-20260505-0
file: data/en.wikipedia.org/wiki/Disrupted_planet-0.md
category: reference
title: Disrupted planet
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Disrupted_planet
date_saved: 2026-05-05T11:00:55.190430+00:00
instance: kb-cron
parent: disrupted-planet-20260505-0
summary:
In astronomy, a disrupted planet is a planet or exoplanet or, perhaps on a somewhat smaller scale, a planetary-mass object, planetesimal, moon, exomoon or asteroid that has been disrupted or destroyed by a nearby or passing astronomical body or object such as a star. Necroplanetology is the related study of such a process. The result of such a disruption may be the production of excessive amounts of related gas, dust and debris, which may eventually surround the parent star in the form of a circumstellar disk or debris disk. As a consequence, the orbiting debris field may be an "uneven ring of dust", causing erratic light fluctuations in the apparent luminosity of the parent star, as may have been responsible for the oddly flickering light curves associated with the starlight observed from certain variable stars, such as that from Tabby's Star (KIC 8462852), RZ Piscium and WD 1145+017. Excessive amounts of infrared radiation may be detected from such stars, suggestive evidence in itself that dust and debris may be orbiting the stars. == Examples == === Planets === Examples of planets, or their related remnants, considered to have been a disrupted planet, or part of such a planet, include: ‘Oumuamua


id: epic-204376071-20260505-0
file: data/en.wikipedia.org/wiki/EPIC_204376071-0.md
category: reference
title: EPIC 204376071
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/EPIC_204376071
date_saved: 2026-05-05T11:00:56.346030+00:00
instance: kb-cron
parent: epic-204376071-20260505-0
summary:
EPIC 204376071 is an M-type star in the constellation of Scorpius. Parallax measurements by the Gaia space observatory put the star at a distance of about 440 light-years (130 parsecs) from Earth. It is likely a member of the Upper Sco association, and is young enough that it has not yet become a main-sequence star. Unusual light fluctuations of the star, including up to an 80% dimming in brightness (i.e., "single 80% deep occultation of 1-day duration"), were observed by astronomers. The unusual dimming was not only extremely deep, but also substantially asymmetric, with an egress about twice as long as the ingress. Nonetheless, such an unusual dimming for EPIC 204376071 is much greater than the 22% dimming observed for Tabby's star. Several explanations have been presented to explain the unusual dimming of the EPIC 204376071 star: one, orbiting dust or small particles; or two, a "transient accretion event of dusty material near the corotation radius of the star". The unusual light curve of the star is similar to the light curve of a candidate exoplanet, KIC 10403228 b, which may have been caused by a "tilted ring system" orbiting the planet. In the case of EPIC 204376071, an orbiting


id: faint-young-sun-paradox-20260505-0
file: data/en.wikipedia.org/wiki/Faint_young_Sun_paradox-0.md
category: reference
title: Faint young Sun paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Faint_young_Sun_paradox
date_saved: 2026-05-05T11:00:58.880444+00:00
instance: kb-cron
parent: faint-young-sun-paradox-20260505-0
summary:
The faint young Sun paradox or faint young Sun problem describes the apparent contradiction between observations of liquid water early in Earth's history and the astrophysical expectation that the Sun's output would have been only 70 percent as intense during that epoch as it is during the modern epoch. The paradox is this: with the young Sun's output at only 70 percent of its current output, early Earth would be expected to be completely frozen, but early Earth seems to have had liquid water and supported life. The issue was raised by astronomers Carl Sagan and George Mullen in 1972. Proposed resolutions of this paradox have taken into account greenhouse effects, changes to planetary albedo, astrophysical influences, or combinations of these suggestions. The predominant theory is that the greenhouse gas carbon dioxide contributed most to the warming of the Earth. == Solar evolution == Models of stellar structure, especially the standard solar model predict a brightening of the Sun. The brightening is caused by a decrease in the number of particles per unit mass due to nuclear fusion in the Sun's core, from four protons and electrons each to one helium nucleus and two electrons. Fewer particles would exert less


id: faint-young-sun-paradox-20260505-1
file: data/en.wikipedia.org/wiki/Faint_young_Sun_paradox-1.md
category: reference
title: Faint young Sun paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Faint_young_Sun_paradox
date_saved: 2026-05-05T11:00:58.880444+00:00
instance: kb-cron
parent: faint-young-sun-paradox-20260505-0
summary:
=== Cosmic rays === A minority view propounded by the Israeli-American physicist Nir Shaviv uses climatological influences of solar wind combined with a hypothesis of Danish physicist Henrik Svensmark for a cooling effect of cosmic rays. According to Shaviv, the early Sun had emitted a stronger solar wind that produced a protective effect against cosmic rays. In that early age, a moderate greenhouse effect comparable to today's would have been sufficient to explain a largely ice-free Earth. Evidence for a more active early Sun has been found in meteorites. The temperature minimum around 2.4 Ga goes along with a cosmic ray flux modulation by a variable star formation rate in the Milky Way. The reduced solar impact later results in a stronger impact of cosmic ray flux, which is hypothesized to lead to a relationship with climatological variations. === Mass loss from Sun === It has been proposed several times that mass loss from the faint young Sun in the form of stronger solar winds could have compensated for the low temperatures from greenhouse gas forcing. In this framework, the early Sun underwent an extended period of higher solar wind output. Based on exoplanetary data, this caused a mass loss


id: faint-young-sun-paradox-20260505-2
file: data/en.wikipedia.org/wiki/Faint_young_Sun_paradox-2.md
category: reference
title: Faint young Sun paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Faint_young_Sun_paradox
date_saved: 2026-05-05T11:00:58.880444+00:00
instance: kb-cron
parent: faint-young-sun-paradox-20260505-0
summary:
=== Mars === Mars has its own version of the faint young Sun paradox. Martian terrains show clear signs of past liquid water on the surface, including outflow channels, gullies, modified craters, and valley networks. These geomorphic features suggest Mars had an ocean on its surface and river networks that resemble current Earth's during the late Noachian (4.1–3.7 Ga). It is unclear how Mars's orbital pattern, which places it even further from the Sun, and the faintness of the young Sun could have produced what is thought to have been a very warm and wet climate on Mars. Scientists debate over which geomorphological features can be attributed to shorelines or other water flow markers and which can be ascribed to other mechanisms. Nevertheless, the geologic evidence, including observations of widespread fluvial erosion in the southern highlands, are generally consistent with an early warm and semi-arid climate. Given the orbital and solar conditions of early Mars, a greenhouse effect would have been necessary to increase surface temperatures at least 65 K in order for these surface features to have been carved by flowing water. A much denser, CO2-dominated atmosphere has been proposed as a way to produce such a temperature increase.


id: fast-blue-optical-transient-20260505-0
file: data/en.wikipedia.org/wiki/Fast_blue_optical_transient-0.md
category: reference
title: Fast blue optical transient
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fast_blue_optical_transient
date_saved: 2026-05-05T11:01:00.126530+00:00
instance: kb-cron
parent: fast-blue-optical-transient-20260505-0
summary:
In astronomy, a fast blue optical transient (FBOT), or more specifically, luminous fast blue optical transient (LFBOT), is an explosive transient event similar to supernovae and gamma-ray bursts with high optical luminosity, rapid evolution, and predominantly blue emission. The origins of such explosions are currently unclear, with events occurring at not more than 0.1% of the typical core-collapse supernova rate. This class of transients initially emerged from large sky surveys at cosmological distances, yet in recent years a small number have been discovered in the local Universe, most notably AT 2018cow. The precise definition of what constitutes a 'fast blue optical transient' is currently contentious in the literature, largely defined by the observational properties rather than the underlying mechanisms/objects. Even within the class, growing samples of candidates are beginning to reveal significant variation in properties when the objects are studied in greater detail, potentially indicative of different progenitor channels or explosion mechanisms. == List == == See also == Gamma-ray burst Intermediate luminosity optical transient Supernova == References == == External links == Video (29:36) – Fast optical transients on YouTube (2016; Harvard University)


id: fast-radio-burst-20260505-0
file: data/en.wikipedia.org/wiki/Fast_radio_burst-0.md
category: reference
title: Fast radio burst
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fast_radio_burst
date_saved: 2026-05-05T11:01:01.319119+00:00
instance: kb-cron
parent: fast-radio-burst-20260505-0
summary:
In radio astronomy, a fast radio burst (FRB) is a transient radio wave of duration ranging from a fraction of a millisecond, for an ultra-fast radio burst, to 3 seconds, caused by a high-energy astrophysical process that is not yet understood. Astronomers estimate the average FRB releases as much energy in a millisecond as the Sun puts out in three days. While extremely energetic at their source, the strength of the signal reaching Earth has been described as 1,000 times less than from a mobile phone on the Moon. The first FRB was discovered by Duncan Lorimer and his student David Narkevic in 2007 when they were looking through archival pulsar survey data, and it is therefore commonly referred to as the Lorimer burst. Many FRBs have since been recorded, including several that have been detected repeating in seemingly irregular ways. Only one FRB has been detected to repeat in a regular way: FRB 180916 seems to pulse every 16.35 days. Most FRBs are extragalactic, but the first Milky Way FRB was detected by the CHIME radio telescope in April 2020. In June 2021, astronomers reported over 500 FRBs from outer space detected in one year. When FRBs are polarized,


id: fast-radio-burst-20260505-1
file: data/en.wikipedia.org/wiki/Fast_radio_burst-1.md
category: reference
title: Fast radio burst
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fast_radio_burst
date_saved: 2026-05-05T11:01:01.319119+00:00
instance: kb-cron
parent: fast-radio-burst-20260505-0
summary:
=== Extragalactic origin === The interferometer UTMOST has put a lower limit of 10,000 kilometers for the distance to the FRBs it has detected, supporting the case for an astronomical, rather than terrestrial, origin (because signal sources on Earth are ruled out as being closer than this limit). This limit can be determined from the fact that closer sources would have a curved wave front that could be detected by the multiple antennas of the interferometer. Fast radio bursts have pulse dispersion measurements > 100 pc cm−3, much larger than expected for a source inside the Milky Way galaxy and consistent with propagation through an ionized plasma. Furthermore, their distribution is isotropic (not especially coming from the galactic plane); consequently they are conjectured to be of extragalactic origin. == Origin hypotheses == Because of the isolated nature of the observed phenomenon, the nature of the source remains speculative. As of 2022, there is no generally accepted single explanation, although a magnetar has been identified as a possible source. The sources are thought to be a few hundred kilometers or less in size, as the bursts last for only a few milliseconds. Causation is limited by the speed of light, about


id: fast-radio-burst-20260505-2
file: data/en.wikipedia.org/wiki/Fast_radio_burst-2.md
category: reference
title: Fast radio burst
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fast_radio_burst
date_saved: 2026-05-05T11:01:01.319119+00:00
instance: kb-cron
parent: fast-radio-burst-20260505-0
summary:
=== Hypotheses for repeating FRBs === Repeated bursts of FRB 121102 have initiated multiple origin hypotheses. A coherent emission phenomenon known as superradiance, which involves large-scale entangled quantum mechanical states possibly arising in environments such as active galactic nuclei, has been proposed to explain these and other associated observations with FRBs (e.g. high event rate, repeatability, variable intensity profiles). In July 2019, astronomers reported that non-repeating Fast Radio Bursts may not be one-off events, but actually FRB repeaters with repeat events that have gone undetected and, further, that FRBs may be formed by events that have not yet been seen or considered. Additional possibilities include that FRBs may originate from nearby stellar flares. A FRB with multiple periodic component peaks lasting over 3 seconds was reported in 2022. A neutron star has been proposed as the origin of this FRB. == Bursts observed == === Naming === Fast radio bursts are named by the date the signal was recorded, as "FRB YYMMDD", with a letter appended to distinguish multiple sources first recorded on the same date. The name is of the presumed source rather than the burst of radio waves, so repeated or subsequent bursts from the same apparent location


id: fast-radio-burst-20260505-3
file: data/en.wikipedia.org/wiki/Fast_radio_burst-3.md
category: reference
title: Fast radio burst
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fast_radio_burst
date_saved: 2026-05-05T11:01:01.319119+00:00
instance: kb-cron
parent: fast-radio-burst-20260505-0
summary:
An observation in 2012 of a fast radio burst (FRB 121102) in the direction of Auriga in the northern hemisphere using the Arecibo radio telescope confirmed the extragalactic origin of fast radio pulses by an effect known as plasma dispersion. In November 2015, astronomer Paul Scholz at McGill University in Canada, found ten non-periodically repeated fast radio pulses in archival data gathered in May and June 2015 by the Arecibo radio telescope. The ten bursts have dispersion measures and sky positions consistent with the original burst FRB 121102, detected in 2012. Like the 2012 burst, the 10 bursts have a plasma dispersion measure that is three times larger than possible for a source in the Milky Way Galaxy. The team thinks that this finding rules out self-destructive, cataclysmic events that could occur only once, such as the collision between two neutron stars. According to the scientists, the data support an origin in a young rotating neutron star (pulsar), or in a highly magnetized neutron star (magnetar), or from highly magnetized pulsars travelling through asteroid belts, or from an intermittent Roche lobe overflow in a neutron star-white dwarf binary. On 16 December 2016 six new FRBs were reported in the same


id: fast-radio-burst-20260505-4
file: data/en.wikipedia.org/wiki/Fast_radio_burst-4.md
category: reference
title: Fast radio burst
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fast_radio_burst
date_saved: 2026-05-05T11:01:01.319119+00:00
instance: kb-cron
parent: fast-radio-burst-20260505-0
summary:
=== 2017 === The upgraded Molonglo Observatory Synthesis Telescope (UTMOST), near Canberra (Australia), reported finding three more FRBs. A 180-day three-part survey in 2015 and 2016 found three FRBs at 843 MHz. Each FRB located with a narrow elliptical 'beam'; the relatively narrow band 828–858 MHz gives a less precise dispersion measure (DM). A short survey using part of Australian Square Kilometre Array Pathfinder (ASKAP) found one FRB in 3.4 days. FRB170107 was bright with a fluence of 58±6 Jy ms. According to Anastasia Fialkov and Abraham Loeb, FRB's could be occurring as often as once per second. Earlier research could not identify the occurrence of FRB's to this degree. === 2018 === Three FRBs were reported in March 2018 by Parkes Observatory in Australia. One (FRB 180309) had the highest signal-to-noise ratio yet seen of 411. The unusual CHIME (Canadian Hydrogen Intensity Mapping Experiment) radio telescope, operational from September 2018, can be used to detect "hundreds" of fast radio bursts as a secondary objective to its cosmological observations. FRB 180725A was reported by CHIME as the first detection of a FRB under 700 MHz – as low as 580 MHz. In October 2018, astronomers reported 19 more new non-repeating


id: fast-radio-burst-20260505-5
file: data/en.wikipedia.org/wiki/Fast_radio_burst-5.md
category: reference
title: Fast radio burst
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fast_radio_burst
date_saved: 2026-05-05T11:01:01.319119+00:00
instance: kb-cron
parent: fast-radio-burst-20260505-0
summary:
==== FRB 191228 ==== On 31 December 2019, Australian astronomers, using the Australian Square Kilometre Array Pathfinder (ASKAP), reported the detection of FRB 191228 in the Piscis Austrinus constellation (RA = 22:57(2), DEC = -29:46(40)). === 2020 === ==== FRB 200120E ==== In February & March 2022, astronomers reported that a globular cluster of M81, a grand design spiral galaxy about 12 million light-years away, may be the source of FRB 20200120E, a repeating fast radio burst. ==== FRB 200317 ==== Astronomers reported the discovery of FRB 20200317A (RA 16h22m45s, DEC p+56d44m50s) with FAST (Five-hundred-meter Aperture Spherical radio Telescope) in archival data on 22 September 2023. The detected FRB is "one of the faintest FRB sources detected so far", according to the report. ==== FRB 200428 ==== On 28 April 2020, astronomers at the Canadian Hydrogen Intensity Mapping Experiment (CHIME), reported the detection of a bright radio burst from the direction of the Galactic magnetar SGR 1935+2154 about 30,000 light years away in the Vulpecula constellation. The burst had a DM of 332.8 pc/cc. The STARE2 team independently detected the burst and reported that the burst had a fluence of >1.5 MJy ms, establishing the connection between this burst and


id: fast-radio-burst-20260505-6
file: data/en.wikipedia.org/wiki/Fast_radio_burst-6.md
category: reference
title: Fast radio burst
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fast_radio_burst
date_saved: 2026-05-05T11:01:01.319119+00:00
instance: kb-cron
parent: fast-radio-burst-20260505-0
summary:
==== FRB 220912 ==== On 15 October 2022, astronomers at CHIME/FRB reported the detection of nine bursts in three days of FRB 20220912A. Since later bursts observed between 15 October 2022 and 29 October 2022 by the CHIME/FRB collaboration, astronomers, afterwards, at the Allen Telescope Array (ATA), on 1 November 2022, reported eight more bursts from FRB 20220912A. ATA coordinates were first set to the original settings (23h09m05.49s + 48d42m25.6s) and then later to the newly updated ones (23h09m04.9s +48d42m25.4s). On 13 November 2022, further burst activity of FRB 20220912A was reported by the Tianlai Dish Pathfinder Array in Xinjiang, China and, on 5 December 2022, from several other observatories. On 13 December 2022, over a hundred bursts from FRB 220912A were reported by the Upgraded Giant Metrewave Radio Telescope (uGMRT), operated by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research in India. On 21 December 2022, several more bright bursts of FRB 220912A using the Westerbork-RT1 were reported. Four more bursts were reported on 13 July 2023 by the Medicina Radio Observatory (specifically by the Medicina Northern Cross (MNC) radio telescope) in Bologna, Italy. Based on four bursts, burst rate constraints of FRB 20220912A


id: fermi-paradox-20260505-0
file: data/en.wikipedia.org/wiki/Fermi_paradox-0.md
category: reference
title: Fermi paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fermi_paradox
date_saved: 2026-05-05T11:01:02.535314+00:00
instance: kb-cron
parent: fermi-paradox-20260505-0
summary:
The Fermi paradox is the discrepancy between the lack of conclusive evidence of advanced extraterrestrial life and the apparently high likelihood of its existence. In simple terms, the Fermi paradox asks why, given the vast number of stars and potentially habitable planets in our observable universe, there is no clear evidence of extraterrestrial civilizations. The paradox is named after physicist Enrico Fermi, who informally posed the question—remembered by Emil Konopinski as "But where is everybody?"—during a 1950 conversation at Los Alamos with colleagues Konopinski, Edward Teller, and Herbert York. The paradox first appeared in print in a 1963 paper by Carl Sagan and the paradox has since been fully characterized by scientists. Early formulations of the paradox have also been identified in writings by Bernard Le Bovier de Fontenelle (1686) and Jules Verne (1865), and by Soviet rocket scientist Konstantin Tsiolkovsky (1933). There have been many attempts to resolve the Fermi paradox, such as suggesting that intelligent extraterrestrial beings are extremely rare, that the lifetime of such civilizations is short, or that they exist but (for various reasons) humans see no evidence. == Chain of reasoning == Some of the facts and hypotheses that together serve to highlight the apparent


id: fermi-paradox-20260505-1
file: data/en.wikipedia.org/wiki/Fermi_paradox-1.md
category: reference
title: Fermi paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fermi_paradox
date_saved: 2026-05-05T11:01:02.535314+00:00
instance: kb-cron
parent: fermi-paradox-20260505-0
summary:
The Fermi question first appeared in print in a footnote of a 1963 paper by Carl Sagan. Two years later, Stephen Dole noted the dilemma at a symposium—"If there are so many advanced forms of life around, where is everybody?"—but did not attribute it to Fermi. A chapter of Intelligent Life in the Universe, co-authored by Sagan and Iosif Shklovsky, was headlined with the Fermi-attributed "Where are they?" The Fermi question also appeared in NASA's 1970 Project Cyclops report, a 1973 book by Sagan, and a 1975 article in JBIS Interstellar Studies by David Viewing that first described it as a paradox. Later that year, Michael Hart published a detailed examination of the paradox in the Quarterly Journal of the Royal Astronomical Society. Hart, who concluded that "we are the first civilization in our Galaxy", proposed four broad categories of solutions to the paradox: those that are physical (a space travel limitation), sociological (aliens choose not to visit Earth), temporal (aliens have not had time to travel to Earth), or that extraterrestrials have already visited. His paper sparked significant interest in the paradox among academics and even politicians, with a discussion held in the House of Lords. A seminal response—"Extraterrestrial


id: fermi-paradox-20260505-2
file: data/en.wikipedia.org/wiki/Fermi_paradox-2.md
category: reference
title: Fermi paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fermi_paradox
date_saved: 2026-05-05T11:01:02.535314+00:00
instance: kb-cron
parent: fermi-paradox-20260505-0
summary:
N = R ∗ ⋅ f p ⋅ n e ⋅ f l ⋅ f i ⋅ f c ⋅ L , {\displaystyle N=R_{*}\cdot f_{\mathrm {p} }\cdot n_{\mathrm {e} }\cdot f_{\mathrm {l} }\cdot f_{\mathrm {i} }\cdot f_{\mathrm {c} }\cdot L,} where N {\displaystyle N} is the number of technologically advanced civilizations in the Milky Way galaxy, and N {\displaystyle N} is asserted to be the product of R ∗ {\displaystyle R_{*}} , the rate of formation of stars in the galaxy; f p {\displaystyle f_{p}} , the fraction of those stars with planetary systems; n e {\displaystyle n_{e}} , the number of planets, per solar system, with an environment suitable for organic life; f l {\displaystyle f_{l}} , the fraction of those suitable planets whereon organic life appears; f i {\displaystyle f_{i}} , the fraction of life-bearing planets whereon intelligent life appears; f c {\displaystyle f_{c}} , the fraction of civilizations that reach the technological level whereby detectable signals may be dispatched; and L {\displaystyle L} , the length of time that those civilizations dispatch their signals. The fundamental problem is that the last four terms ( f l {\displaystyle f_{l}} , f i {\displaystyle f_{i}} , f c {\displaystyle


id: fermi-paradox-20260505-3
file: data/en.wikipedia.org/wiki/Fermi_paradox-3.md
category: reference
title: Fermi paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fermi_paradox
date_saved: 2026-05-05T11:01:02.535314+00:00
instance: kb-cron
parent: fermi-paradox-20260505-0
summary:
=== Anthropics === Anthropic reasoning and the question of why we happen to find ourselves as humans creates a number of potential problems for astrobiology. Walter Barta argues that Hanson's grabby aliens model creates an anthropic dilemma. According to Hanson's model, most observers in our reference class should be grabby aliens themselves. This leads to the question of why we do not find ourselves as grabby aliens, but rather as a species confined to a single planet. == Empirical evidence == There are two parts of the Fermi paradox that rely on empirical evidence—that there are many potentially habitable planets, and that humans see no evidence of life. The first point, that many suitable planets exist, was an assumption in Fermi's time, but is since supported by the discovery that exoplanets are common. Existing models predict billions of habitable worlds in the Milky Way. The second part of the paradox, that humans see no evidence of extraterrestrial life, is also an active field of scientific research. This includes both efforts to find any indication of life, and efforts specifically directed to finding intelligent life. These searches have been made since 1960, and several are ongoing. Although astronomers do not usually


id: fermi-paradox-20260505-4
file: data/en.wikipedia.org/wiki/Fermi_paradox-4.md
category: reference
title: Fermi paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fermi_paradox
date_saved: 2026-05-05T11:01:02.535314+00:00
instance: kb-cron
parent: fermi-paradox-20260505-0
summary:
In 1959, Freeman Dyson observed that every developing human civilization constantly increases its energy consumption, and he conjectured that a civilization might try to harness a large part of the energy produced by a star. He proposed a hypothetical "Dyson sphere" as a means: a shell or cloud of objects enclosing a star to absorb and utilize as much radiant energy as possible. Such a feat of astroengineering would drastically alter the observed spectrum of the star involved, changing it at least partly from the normal emission lines of a natural stellar atmosphere to those of black-body radiation, probably with a peak in the infrared. Dyson speculated that advanced alien civilizations might be detected by examining the spectra of stars and searching for such an altered spectrum. There have been attempts to find evidence of Dyson spheres that would alter the spectra of their core stars. Direct observation of thousands of galaxies has shown no explicit evidence of artificial construction or modifications. In October 2015, there was speculation that a dimming of light from star KIC 8462852, observed by the Kepler space telescope, could have been a result of such a Dyson sphere under construction. However, in 2018, further observations


id: fermi-paradox-20260505-5
file: data/en.wikipedia.org/wiki/Fermi_paradox-5.md
category: reference
title: Fermi paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fermi_paradox
date_saved: 2026-05-05T11:01:02.535314+00:00
instance: kb-cron
parent: fermi-paradox-20260505-0
summary:
New life might commonly die out due to runaway heating or cooling on their fledgling planets. On Earth, there have been numerous major extinction events that destroyed the majority of complex species alive at the time; the extinction of the non-avian dinosaurs is the best known example. These are thought to have been caused by events such as impact from a large asteroid, massive volcanic eruptions, or astronomical events such as gamma-ray bursts. It may be the case that such extinction events are common throughout the universe and periodically destroy intelligent life, or at least its civilizations, before the species is able to develop the technology to communicate with other intelligent species. However, the chances of extinction by natural events may be very low on the scale of a civilization's lifetime. Based on an analysis of impact craters on Earth and the Moon, the average interval between impacts large enough to cause global consequences (like the Chicxulub impact) is estimated to be around 100 million years. === Evolutionary explanations === ==== It is the nature of intelligent life to destroy itself ==== This is the argument that technological civilizations may usually or invariably destroy themselves before or shortly after developing


id: fermi-paradox-20260505-6
file: data/en.wikipedia.org/wiki/Fermi_paradox-6.md
category: reference
title: Fermi paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fermi_paradox
date_saved: 2026-05-05T11:01:02.535314+00:00
instance: kb-cron
parent: fermi-paradox-20260505-0
summary:
Another hypothesis is that an intelligent species beyond a certain point of technological capability will destroy other intelligent species as they appear, perhaps by using self-replicating probes. Science fiction writer Fred Saberhagen has explored this idea in his Berserker series, as has physicist Gregory Benford and also, science fiction writer Greg Bear in his The Forge of God novel, and later Liu Cixin in his The Three-Body Problem series. A species might undertake such extermination out of expansionist motives, greed, paranoia, or aggression. In 1981, cosmologist Edward Harrison argued that such behavior would be an act of prudence: an intelligent species that has overcome its own self-destructive tendencies might view any other species bent on galactic expansion as a threat. It has also been suggested that a successful alien species would be a superpredator, as are humans. Another possibility invokes the "tragedy of the commons" and the anthropic principle: the first lifeform to achieve interstellar travel will necessarily (even if unintentionally) prevent competitors from arising, and humans simply happen to be first. ==== Civilizations only broadcast detectable signals for a brief period of time ==== It may be that alien civilizations are detectable through their radio emissions for only a


id: fermi-paradox-20260505-7
file: data/en.wikipedia.org/wiki/Fermi_paradox-7.md
category: reference
title: Fermi paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fermi_paradox
date_saved: 2026-05-05T11:01:02.535314+00:00
instance: kb-cron
parent: fermi-paradox-20260505-0
summary:
==== Alien species may have only settled part of the galaxy ==== According to a study by Frank et al., advanced civilizations may not colonize everything in the galaxy due to their potential adoption of steady states of expansion. This hypothesis suggests that civilizations might reach a stable pattern of expansion where they neither collapse nor aggressively spread throughout the galaxy. A February 2019 article in Popular Science states, "Sweeping across the Milky Way and establishing a unified galactic empire might be inevitable for a monolithic super-civilization, but most cultures are neither monolithic nor super—at least if our experience is any guide." Astrophysicist Adam Frank, along with co-authors such as astronomer Jason Wright, ran a variety of simulations in which they varied such factors as settlement lifespans, fractions of suitable planets, and recharge times between launches. They found many of their simulations seemingly resulted in a "third category" in which the Milky Way remains partially settled indefinitely. The abstract to their 2019 paper states, "These results break the link between Hart's famous 'Fact A' (no interstellar visitors on Earth now) and the conclusion that humans must, therefore, be the only technological civilization in the galaxy. Explicitly, our solutions admit situations


id: fermi-paradox-20260505-8
file: data/en.wikipedia.org/wiki/Fermi_paradox-8.md
category: reference
title: Fermi paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fermi_paradox
date_saved: 2026-05-05T11:01:02.535314+00:00
instance: kb-cron
parent: fermi-paradox-20260505-0
summary:
==== Information is cheaper to transmit than matter is to transfer ==== If a human-capability machine intelligence is possible, and if it is possible to transfer such constructs over vast distances and rebuild them on a remote machine, then it might not make strong economic sense to travel the galaxy by spaceflight. Louis K. Scheffer calculates the cost of radio transmission of information across space to be cheaper than spaceflight by a factor of 108–1017. For a machine civilization, the costs of interstellar travel are therefore enormous compared to the more efficient option of sending computational signals across space to already established sites. After the first civilization has physically explored or colonized the galaxy, as well as sent such machines for easy exploration, then any subsequent civilizations, after having contacted the first, may find it cheaper, faster, and easier to explore the galaxy through intelligent mind transfers to the machines built by the first civilization. However, since a star system needs only one such remote machine, and the communication is most likely highly directed, transmitted at high-frequencies, and at a minimal power to be economical, such signals would be hard to detect from Earth. By contrast, in economics the counter-intuitive


id: fermi-paradox-20260505-9
file: data/en.wikipedia.org/wiki/Fermi_paradox-9.md
category: reference
title: Fermi paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fermi_paradox
date_saved: 2026-05-05T11:01:02.535314+00:00
instance: kb-cron
parent: fermi-paradox-20260505-0
summary:
===== Radio signals cannot be straightforwardly detected at interstellar distances ===== The greatest challenge is the sheer size of the radio search needed to look for signals (effectively spanning the entire observable universe), the limited amount of resources committed to SETI, and the sensitivity of modern instruments. SETI estimates, for instance, that with a radio telescope as sensitive as the Arecibo Observatory, Earth's television and radio broadcasts would only be detectable at distances up to 0.3 light-years, less than 1/10 the distance to the nearest star. A signal is much easier to detect if it consists of a deliberate, powerful transmission directed at Earth. Such signals could be detected at ranges of hundreds to tens of thousands of light-years distance. However, this means that detectors must be listening to an appropriate range of frequencies, and be in that region of space to which the beam is being sent. Many SETI searches assume that extraterrestrial civilizations will be broadcasting a deliberate signal, like the Arecibo message, in order to be found. Moreover, as human communication technology has advanced, humans have reduced the use of broadband radio transmissions in favor of more efficient and higher-bandwidth methods such as satellite communication and fibre


id: fermi-paradox-20260505-10
file: data/en.wikipedia.org/wiki/Fermi_paradox-10.md
category: reference
title: Fermi paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fermi_paradox
date_saved: 2026-05-05T11:01:02.535314+00:00
instance: kb-cron
parent: fermi-paradox-20260505-0
summary:
==== Intelligent life exists buried below the surfaces of ice planets ==== Planetary scientist Alan Stern put forward the idea that there could be a number of worlds with subsurface oceans (such as Jupiter's Europa or Saturn's Enceladus). The surface would provide a large degree of protection from such things as cometary impacts and nearby supernovae, as well as creating a situation in which a much broader range of orbital configurations are capable of supporting life. Life, and potentially intelligence and civilization, could evolve below the surface of such a planet, but be very hard to detect, insofar as it is generally only possible to observe the surface of planets from space. Stern states, "If they have technology, and let's say they're broadcasting, or they have city lights or whatever—we can't see it in any part of the spectrum, except maybe very-low-frequency [radio]." Moreover, such a civilization may have great difficulty getting to space, insofar as even getting to the surface of their world could present a considerable engineering challenge involving tunneling through many kilometres of ice. This may severely hamper their ability to communicate with us. ==== Advanced civilizations may limit their search for life to technological signatures ====


id: fermi-paradox-20260505-11
file: data/en.wikipedia.org/wiki/Fermi_paradox-11.md
category: reference
title: Fermi paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fermi_paradox
date_saved: 2026-05-05T11:01:02.535314+00:00
instance: kb-cron
parent: fermi-paradox-20260505-0
summary:
The zoo hypothesis states that intelligent extraterrestrial life exists and does not contact life on Earth to allow for its natural evolution and development as a sort of cosmic closed nature reserve. A variation on the zoo hypothesis is the laboratory hypothesis, where humanity has been or is being subject to experiments, with Earth or the Solar System effectively serving as a laboratory. The zoo hypothesis may break down under the uniformity of motive flaw: all it takes is a single culture or civilization (or even a faction or rogue actor within one) to decide to act contrary to the interplanetary consensus, and the probability of such a violation of hegemony increases with the number of civilizations, tending not towards a galactic league with a single policy towards Earth, but towards multiple competing factions. However, if artificial superintelligences are paramount in galactic politics, and such intelligences tend towards consolidation behind a central authority, then this would at least partially address the uniformity of motive flaw by dissuading rogue behavior. Analysis of the inter-arrival times between civilizations in the galaxy based on common astrobiological assumptions suggests that the initial civilization would have a commanding lead over the later arrivals, inasmuch as


id: g-dwarf-problem-20260505-0
file: data/en.wikipedia.org/wiki/G-dwarf_problem-0.md
category: reference
title: G-dwarf problem
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/G-dwarf_problem
date_saved: 2026-05-05T11:01:04.825572+00:00
instance: kb-cron
parent: g-dwarf-problem-20260505-0
summary:
In astronomy, the G-dwarf problem refers to the apparent discrepancy in the distribution of metallicity levels in stars of different populations as compared to closed box models of galactic chemical evolution. According to closed box models, which represent galaxies without outside non-metallic material inflow, the distribution of metallicity levels in stars should follow a logarithmic curve. This amounts to high and low mass stars having the least metallicity, with G-type stars inbetween. However, these models are inconsistent with Milky Way observations. Other galaxies have been shown to have the same problem. The name comes from G-type stars, which are bright enough to be studied easily, yet are most often found unevolved. This provides an extensive look at relatively young stars. Despite this, the G-dwarf problem has also been observed in K and M dwarfs (the M dwarf problem). == See also == Solar analog List of nearest bright stars List of nearest stars and brown dwarfs Main sequence G-type main-sequence star == References ==


id: galactic-center-gev-excess-20260505-0
file: data/en.wikipedia.org/wiki/Galactic_Center_GeV_excess-0.md
category: reference
title: Galactic Center GeV excess
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Galactic_Center_GeV_excess
date_saved: 2026-05-05T11:01:06.065797+00:00
instance: kb-cron
parent: galactic-center-gev-excess-20260505-0
summary:
The Galactic Center GeV Excess (GCE) is an unexpected surplus of gamma-ray radiation coming from the center of the Milky Way Galaxy. This approximately spherical source of radiation was first detected in 2009 by the Large Area Telescope of the Fermi Gamma-ray Space Telescope and is unexplained by direct observation of possible sources. Two percent of the gamma ray radiation in a 30° radius circle around the Galactic Center is attributed to the GCE. As of 2025, this excessive (and diffused) gamma-ray radiation is not well understood by astronomers. Some astronomers argue that self-annihilating dark matter (which is not otherwise known to radiate) may be the cause of the GCE. This would also explain the excess diffuse microwave glow of the galactic center that had been discovered previously by the WMAP satellite. Other astronomers prefer a population of pulsars (which have not been observed) as the source of the gamma-ray excess. Astronomers have suggested that self-annihilating dark matter may be a dominant contributor to the GCE, based on analysis using non-Poissonian template fitting statistical methods, wavelet methods, and studies by other astronomers may support this idea. More recently, in August 2020, other astronomers have reported that self-annihilating dark matter may


id: gpm-j1839-10-20260505-0
file: data/en.wikipedia.org/wiki/GPM_J1839−10-0.md
category: reference
title: GPM J1839−10
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/GPM_J1839−10
date_saved: 2026-05-05T11:01:07.267702+00:00
instance: kb-cron
parent: gpm-j1839-10-20260505-0
summary:
GPM J1839−10 is a potentially unique ultra-long period magnetar located about 15,000 light-years away from Earth in the Scutum constellation, in the Milky Way. It was discovered by a team of scientists at Curtin University using the Murchison Widefield Array. Its unusual characteristics violate current theory and prompted a search of other radio telescope archives, including the Giant Metrewave Radio Telescope and the Very Large Array, which revealed evidence of the object dating back to 1988. The signature of the object went unnoticed because scientists did not know to look for its unusual behavior. The current understanding of neutron stars is that below a certain rate of rotation, called "the death line", they cease emissions. Uniquely, not only does GPM J1839−10 have an extremely slow rotation of approximately twenty-two minutes, it emits bursts of radio waves lasting up to five minutes, for which there is currently no generally accepted explanation. == See also == GLEAM-X J162759.5−523504.3 GCRT J1745−3009 PSR J0901–4046 == Further reading == P. Beniamini; Z. Wadiasingh; B. D. Metzger (2020). "Periodicity in recurrent fast radio bursts and the origin of ultralong period magnetars". Monthly Notices of the Royal Astronomical Society. 496 (3) (published 23 June 2020): 3390–3401. arXiv:2003.12509.


id: hd-139139-20260505-0
file: data/en.wikipedia.org/wiki/HD_139139-0.md
category: reference
title: HD 139139
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/HD_139139
date_saved: 2026-05-05T11:01:09.708720+00:00
instance: kb-cron
parent: hd-139139-20260505-0
summary:
HD 139139 (also known as EPIC 249706694) is likely part of a bound pair system of main sequence stars about 350 light-years (110 parsecs) away from Earth in the constellation Libra. HD 139139 is a G-type main-sequence star, a little larger and more luminous than the Sun, and at an almost identical temperature. It has an apparent magnitude of 9.8. The companion star is thought to be a K5-K7 red dwarf 3.3″ away from HD 139139. It is about three magnitudes fainter and has a temperature of between 4,100 and 4,300 K. Both stars have a similar proper motion, meaning they may form a gravitationally-bound binary pair. HD 139139 exhibits dips in brightness similar to those caused by transiting Earth-like planets. The Kepler space telescope observed 28 dips in their brightness over an 87-day period (23 August – 20 November 2017). The dips do not appear to be periodic as would be expected if they were due to transiting planets. It is unknown which of the two stars produces the dimming events. Potential explanations that have been investigated include planets transiting a binary star, planets that are perturbing the orbits of each other producing large transit timing variations, a disintegrating


id: iptf14hls-20260505-0
file: data/en.wikipedia.org/wiki/IPTF14hls-0.md
category: reference
title: IPTF14hls
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/IPTF14hls
date_saved: 2026-05-05T11:01:10.902891+00:00
instance: kb-cron
parent: iptf14hls-20260505-0
summary:
iPTF14hls is an unusual supernova star that erupted continuously for about 1,000 days beginning in September 2014 before becoming a remnant nebula. It had previously erupted in 1954. None of the theories nor proposed hypotheses fully explain all the aspects of the object. == Observations == The star iPTF14hls was discovered in September 2014 by the Intermediate Palomar Transient Factory, and it was first made public in November 2014 by the CRTS survey as CSS141118:092034+504148. Based on that information, it was confirmed as an exploding star in January 2015. It was thought then that it was a single supernova event (Type II-P) that would dim in about 100 days, but instead, it continued its eruption for about 1,000 days while fluctuating in brightness at least five times. The brightness varied by as much as 50%, going through five peaks. Also, rather than cooling down with time as expected of a Type II-P supernova, the object maintains a near-constant temperature of about 5000–6000 K. Checks of photographs from the past found one from 1954 showing an explosion in the same location. Since 1954, the star has exploded six times. The principal investigator is Iair Arcavi. His international team used the Low-Resolution


id: iptf14hls-20260505-1
file: data/en.wikipedia.org/wiki/IPTF14hls-1.md
category: reference
title: IPTF14hls
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/IPTF14hls
date_saved: 2026-05-05T11:01:10.902891+00:00
instance: kb-cron
parent: iptf14hls-20260505-0
summary:
=== Shock interaction === Jennifer E Andrews and Nathan Smith hypothesised that the observed light spectrum is a clear signature of shock interaction of ejected material with dense circumstellar material (CSM). They proposed that a typical explosion energy, with "enveloped" or "swallowed" CSM interaction—as seen in some recent supernovae, including SN 1998S, SN 2009ip, and SN 1993J—could "explain the peculiar evolution of iPTF14hls." In December 2017, a team using the Fermi Gamma-ray Space Telescope reported that they may have detected in iPTF14hls, for the first time, high energy gamma-ray emission from a supernova. The gamma-ray source appears ~ 300 days after the explosion of iPTF14hls, and is still observable, but more observations are needed to verify that iPTF14hls is the exact source of the observed gamma-ray emission. If the association between the gamma-ray source and iPTF14hls is real, then there are difficulties with modelling its gamma-ray emission in the framework of particle acceleration in supernova-ejecta-produced shock. The energy conversion efficiency needs to be very high, so it is suggested that a jet (anisotropic emission) from a close companion may be necessary to explain some of the observed data. No X-ray emissions have been detected, which makes the interpretation of the


id: jupiter-mass-binary-object-20260505-0
file: data/en.wikipedia.org/wiki/Jupiter-mass_binary_object-0.md
category: reference
title: Jupiter-mass binary object
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Jupiter-mass_binary_object
date_saved: 2026-05-05T11:01:12.130108+00:00
instance: kb-cron
parent: jupiter-mass-binary-object-20260505-0
summary:
Jupiter-mass Binary Objects or JuMBOs are a hypothetical class of celestial objects, defined as a planetary-mass objects orbiting a common center of mass. Reanalysis of early unpublished claims of their discovery was from observations of the Orion Nebula Cluster by the James Webb Space Telescope identified background sources or brown dwarf stars, but no JuMBO objects. == Observations == JuMBOs were reported using data from the James Webb Space Telescope (JWST) survey of the Orion Nebula in late 2022. Using JWST's Near Infrared Camera (NIRCam), astronomers Samuel Pearson and Mark McCaughrean observed a 1.2 × 0.8 parsec region of the inner nebula and Trapezium Cluster over approximately 35 hours. The survey employed twelve different infrared filters specifically chosen to detect molecular absorption features characteristic of very low-mass objects. The planetary-mass objects were identified by looking for distinctive water and methane absorption patterns in their atmospheres. These molecular signatures appear as dips in brightness at specific wavelengths, allowing researchers to distinguish genuine planetary-mass objects from background stars that might appear similarly faint due to dust extinction. This method proved particularly effective for finding objects with temperatures between 890 and 2520 Kelvin. The survey revealed 540 planetary-mass objects, with 40 binary systems


id: list-of-fast-radio-bursts-20260505-0
file: data/en.wikipedia.org/wiki/List_of_fast_radio_bursts-0.md
category: reference
title: List of fast radio bursts
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_fast_radio_bursts
date_saved: 2026-05-05T11:01:13.433856+00:00
instance: kb-cron
parent: list-of-fast-radio-bursts-20260505-0
summary:
This is a list of fast radio bursts. Items are listed here if information about the fast radio burst has been published. Although there could be thousands of detectable events per day, only detected ones are listed. == Notes == == References ==


id: little-red-dot-astronomical-object-20260505-0
file: data/en.wikipedia.org/wiki/Little_red_dot_(astronomical_object)-0.md
category: reference
title: Little red dot (astronomical object)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Little_red_dot_(astronomical_object)
date_saved: 2026-05-05T11:01:14.629713+00:00
instance: kb-cron
parent: little-red-dot-astronomical-object-20260505-0
summary:
Little red dots (LRDs) are a class of small, red-tinted astronomical objects discovered by the James Webb Space Telescope (JWST). Their discovery was announced in March 2024, and they are poorly understood due to limited data collection. They appear to have existed between 0.6 and 1.6 billion years after the Big Bang (13.2 to 12.2 billion years ago), with a majority found around 600 million years post-Big Bang. As of 2025, 341 LRDs have been identified with JWST. The current leading theory is that the LRDs are a form of primordial galaxy, and the original reports identified LRDs as a type of early active galactic nucleus (AGN) containing a supermassive black hole. However, while this explains their age and appearance, they do not have the same characteristics as known AGNs. For example, they do not appear to emit X-rays, have a flattened rather than steeply rising infrared spectrum, and display very little variability between themselves. In July 2025 it was proposed that LRDs were instead supermassive non-metallic primordial stars—also known as population III stars—of perhaps a million solar masses, seen in the last few thousands of years of their lifetimes. Theoretical modelling of such stars appeared to closely match the


id: little-red-dot-astronomical-object-20260505-1
file: data/en.wikipedia.org/wiki/Little_red_dot_(astronomical_object)-1.md
category: reference
title: Little red dot (astronomical object)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Little_red_dot_(astronomical_object)
date_saved: 2026-05-05T11:01:14.629713+00:00
instance: kb-cron
parent: little-red-dot-astronomical-object-20260505-0
summary:
the Balmer break, emission lines, and Hα absorption line are instead most plausibly explained by a black hole star (BH*) scenario, in which dense gas surrounds a powerful ionising source. In contrast to recently proposed BH* models of dust-reddened AGN, we show that spectral fits in the rest UV to near-infrared favour an intrinsically redder continuum over strong dust reddening. This may point to a super-Eddington accreting massive black hole or, possibly, the presence of (super)massive stars in a nuclear star cluster. The Cliff is the clearest evidence to date that at least some LRDs are not ultra-dense massive galaxies, and are instead powered by a central ionising source embedded in dense, absorbing gas. === CAPERS-LRD-z9 === CAPERS-LRD-z9 is an LRD confirmed to be a broad-line active galactic nucleus (BLAGN) with the red-shift z = 9.288. It is the highest red-shift AGN known. CAPERS-LRD-z9 exhibits a prominent Balmer break and "provides strong evidence in support of the 'dense-gas-enshrouded AGN'" explanation. These unusual Balmer jumps are notable properties of LDRs, causing difficulties in observations and spectroscopic analysis. Some LDRs exhibit a symmetrical density distribution of electron scattering, thus a gaseous envelope absorbing nebular spectra is a credible possibility. === A2744–45924 ===


id: lunar-swirls-20260505-0
file: data/en.wikipedia.org/wiki/Lunar_swirls-0.md
category: reference
title: Lunar swirls
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Lunar_swirls
date_saved: 2026-05-05T11:01:15.790463+00:00
instance: kb-cron
parent: lunar-swirls-20260505-0
summary:
Lunar swirls are enigmatic features found across the Moon's surface, which are characterized by having a high albedo, appearing optically immature (i.e. having the optical characteristics of a relatively young regolith), and (often) having a sinuous shape. Their curvilinear shape is often accentuated by low albedo regions that wind between the bright swirls. They appear to overlay the lunar surface, superposed on craters and ejecta deposits, but impart no observable topography. Swirls have been identified on the lunar maria and on highlands - they are not associated with a specific lithologic composition. Swirls on the maria are characterized by strong albedo contrasts and complex, sinuous morphology, whereas those on highland terrain appear less prominent and exhibit simpler shapes, such as single loops or diffuse bright spots. == Association with magnetic anomalies == The lunar swirls are coincident with regions of the magnetic field of the Moon with relatively high strength on a planetary body that lacks, and may never have had, an active core dynamo with which to generate its own magnetic field. Every swirl has an associated magnetic anomaly, but not every magnetic anomaly has an identifiable swirl. Orbital magnetic field mapping by the Apollo 15 and 16 sub-satellites,


id: m-sigma-relation-20260505-0
file: data/en.wikipedia.org/wiki/M–sigma_relation-0.md
category: reference
title: M–sigma relation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/M–sigma_relation
date_saved: 2026-05-05T11:01:16.989418+00:00
instance: kb-cron
parent: m-sigma-relation-20260505-0
summary:
The M–sigma (or M–σ) relation is an empirical correlation between the stellar velocity dispersion σ of a galaxy bulge and the mass M of the supermassive black hole at its center. The M–σ relation was first presented in 1999 during a conference at the Institut d'Astrophysique de Paris in France by David Merritt. Merritt's proposed form of the relation, which he called the "Faber–Jackson law for black holes", was M 10 8 M ⊙ ≈ 3.1 ( σ 200 k m s − 1 ) 4 . {\displaystyle {\frac {M}{10^{8}M_{\odot }}}\approx 3.1\left({\frac {\sigma }{200~{\rm {km}}~{\rm {s}}^{-1}}}\right)^{4}.} where M ⊙ {\displaystyle M_{\odot }} is the solar mass. Publication of the relation in a refereed journal, by two groups, took place the following year. One of many recent studies, based on the growing sample of published black hole masses in nearby galaxies, gives M 10 8 M ⊙ ≈ 1.9 ( σ 200 k m s − 1 ) 5.1 . {\displaystyle {\frac {M}{10^{8}M_{\odot }}}\approx 1.9\left({\frac {\sigma }{200~{\rm {km}}~{\rm {s}}^{-1}}}\right)^{5.1}.} Earlier work demonstrated a relationship between galaxy luminosity and black hole mass, which nowadays has a comparable level of scatter. The M–σ relation is generally interpreted as implying some source of mechanical


id: m-sigma-relation-20260505-1
file: data/en.wikipedia.org/wiki/M–sigma_relation-1.md
category: reference
title: M–sigma relation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/M–sigma_relation
date_saved: 2026-05-05T11:01:16.989418+00:00
instance: kb-cron
parent: m-sigma-relation-20260505-0
summary:
== Importance == Before the M–σ relation was discovered in 2000, a large discrepancy existed between black hole masses derived using three techniques. Direct, or dynamical, measurements based on the motion of stars or gas near the black hole seemed to give masses that averaged ≈1% of the bulge mass (the "Magorrian relation"). Two other techniques—reverberation mapping in active galactic nuclei, and the Sołtan argument, which computes the cosmological density in black holes needed to explain the quasar light—both gave a mean value of M/Mbulge that was a factor ≈10 smaller than implied by the Magorrian relation. The M–σ relation resolved this discrepancy by showing that most of the direct black hole masses published prior to 2000 were significantly in error, presumably because the data on which they were based were of insufficient quality to resolve the black hole's dynamical sphere of influence. The mean ratio of black hole mass to bulge mass in big early-type galaxies is now believed to be approximately 1 : 200, and increasingly smaller as one moves to less massive galaxies. A common use of the M–σ relation is to estimate black hole masses in distant galaxies using the easily measured quantity σ. Black hole


id: o-connell-effect-20260505-0
file: data/en.wikipedia.org/wiki/O'Connell_effect-0.md
category: reference
title: O'Connell effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/O'Connell_effect
date_saved: 2026-05-05T11:01:20.719442+00:00
instance: kb-cron
parent: o-connell-effect-20260505-0
summary:
The O'Connell effect is an asymmetry in the photometric light curve of certain close eclipsing binary stars. It was named after the astronomer Daniel Joseph Kelly O'Connell, SJ of Riverview College in New South Wales who in 1951 studied this phenomenon and distinguished it from the so-called periastron effect described by earlier authors, as it does not necessarily appear near the periastron, when tidal effects and an increase in mutual radiation may cause an increase in luminosity. == The effect == The out-of-eclipse brightness maxima of some binary stars are unequally high. This is contrary to expectations that the observed luminosity of an eclipsing binary should be the same when its components switch positions every half period. The maximum following the primary minimum is nearly always brighter than the preceding one. This is called the positive O'Connell effect, the reverse case is referred to as the negative O'Connell effect. The difference increases with the ellipticity of the stars, and the differences in their sizes and densities. Also, spectral differences have been observed between subsequent maxima. == Attempts at explanation == In some systems where the phenomenon has been observed, such as in CG Cygni, RT Lacertae, XY Ursae Majoris, or


id: odd-radio-circle-20260505-0
file: data/en.wikipedia.org/wiki/Odd_radio_circle-0.md
category: reference
title: Odd radio circle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Odd_radio_circle
date_saved: 2026-05-05T11:01:21.945654+00:00
instance: kb-cron
parent: odd-radio-circle-20260505-0
summary:
In astronomy, an odd radio circle (ORC) is a very large (over 50 times the diameter of our Milky Way ~ 3 million light years) unexplained astronomical object that, at radio wavelengths, is highly circular and brighter along its edges. As of October 2025, there have been 8 such objects (and possibly six more) observed. The observed ORCs are bright at radio wavelengths, but are not visible at visible, infrared or X-ray wavelengths. This is due to the physical process producing this radiation, which is thought to be synchrotron radiation. Three of the ORCs contain optical galaxies in their centers, suggesting that the galaxies might have formed these objects. Only in three cases twin intersecting rings have been seen and they are ORC J2103-6200, ORC J0356-4216 and RAD J131346.9+500320. The last one, RAD J131346.9+500320, discovered by the RAD@home citizen scientists using LOFAR data is currently the farthest and most powerful ORC discovered. == Description == The ORCs were detected in late 2019 after astronomer Anna Kapinska studied a Pilot Survey of the Evolutionary Map of the Universe (EMU), based on the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope array. All of the ORCs are about 1 arcminute in diameter,


id: olbers-paradox-20260505-0
file: data/en.wikipedia.org/wiki/Olbers'_paradox-0.md
category: reference
title: Olbers' paradox
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Olbers'_paradox
date_saved: 2026-05-05T11:01:23.117576+00:00
instance: kb-cron
parent: olbers-paradox-20260505-0
summary:
Olbers' paradox, also known as the dark night paradox or Olbers and Cheseaux's paradox, is a historical argument in astrophysics and physical cosmology that says the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. If the universe were static, homogeneous at a large scale, and populated by an infinite number of stars, any line of sight from Earth must end at the surface of a star and if light from an infinite distance could reach Earth, the night sky should be completely illuminated and very bright. This contradicts the observed darkness and non-uniformity of the night sky. Modern cosmological models do not make all of these assumptions. The darkness of the night sky is one piece of evidence for a dynamic universe, such as the Big Bang model. That model explains the observed darkness by invoking expansion of the universe, which increases the wavelength of visible light originating from the Big Bang to microwave scale via a process known as redshift. The resulting microwave radiation background has wavelengths much longer (millimeters instead of nanometers), which appear dark to the naked eye. Although he was not the first to describe it, the paradox


id: photon-underproduction-crisis-20260505-0
file: data/en.wikipedia.org/wiki/Photon_underproduction_crisis-0.md
category: reference
title: Photon underproduction crisis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photon_underproduction_crisis
date_saved: 2026-05-05T11:01:24.311660+00:00
instance: kb-cron
parent: photon-underproduction-crisis-20260505-0
summary:
The photon underproduction crisis is a cosmological discussion concerning the purported deficit between observed photons and predicted photons. The deficit, or underproduction crisis, is a theoretical problem, arising from comparing observations of ultraviolet light emitted from known populations of galaxies and quasars to theoretical predictions of the amount of ultraviolet light required to simulate the observed distribution of the hydrogen gas in the local universe in a cosmological simulation. The distribution of hydrogen gas was inferred using Lyman-alpha forest observations from Hubble Space Telescope's Cosmic Origins Spectrograph. The amount of light from galaxies and quasars can be estimated from its effect on the distribution of hydrogen and helium in the regions between galaxies. Highly energetic ultraviolet photons can convert electrically neutral hydrogen gas into ionized gas. A team led by Juna Kollmeier reported an unexpected deficit of roughly 400% between ionizing light from known sources and the actual observations of intergalactic hydrogen. Kollmeier and her team wrote in their scientific report, “We examine the statistics of the low-redshift Lyman-alpha forest from smoothed particle hydrodynamic simulations in light of recent improvements in the estimated evolution of the cosmic ultraviolet background (UVB) and recent observations from the Cosmic Origins Spectrograph (COS). We


id: przybylski-s-star-20260505-0
file: data/en.wikipedia.org/wiki/Przybylski's_Star-0.md
category: reference
title: Przybylski's Star
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Przybylski's_Star
date_saved: 2026-05-05T11:01:25.586714+00:00
instance: kb-cron
parent: przybylski-s-star-20260505-0
summary:
Przybylski's Star (pronounced [pʂɨˈbɨlskʲi]), or HD 101065, is a rapidly oscillating Ap star at roughly 356 light-years (109 parsecs) from the Sun in the southern constellation of Centaurus. It is an unusual chemically peculiar star with a unique spectrum showing over-abundances of most rare-earth elements, for example, but under-abundances of more common elements such as iron. == Observation history == This star was first recorded by Benjamin Apthorp Gould on April 29, 1873, and catalogued as the 10th star of Zone 257 with right ascension of 11h 31m 32.89s and declination of −46° 01′ 08″ (at epoch 1875.0) and apparent magnitude of 8.5. In 1961, the Polish-Australian astronomer Antoni Przybylski discovered that this star had a peculiar spectrum that would not fit into the standard framework for stellar classification. Przybylski's observations indicated unusually low amounts of iron and nickel in the star's spectrum, but higher amounts of unusual elements such as strontium, holmium, niobium, scandium, yttrium, caesium, neodymium, praseodymium, thorium, ytterbium, and uranium. In fact, at first Przybylski doubted that iron was present in the spectrum at all. Modern work shows that the iron group elements are somewhat below normal in abundance, but it is clear that the lanthanides, among


id: scp-06f6-20260505-0
file: data/en.wikipedia.org/wiki/SCP_06F6-0.md
category: reference
title: SCP 06F6
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SCP_06F6
date_saved: 2026-05-05T11:01:26.826949+00:00
instance: kb-cron
parent: scp-06f6-20260505-0
summary:
SCP 06F6 is (or was) an astronomical object of unknown type, discovered on 21 February 2006 in the constellation Boötes during a survey of galaxy cluster CL 1432.5+3332.8 with the Hubble Space Telescope's Advanced Camera for Surveys Wide Field Channel. According to research authored by Kyle Barbary of the Supernova Cosmology Project, the object brightened over a period of roughly 100 days, reaching a peak intensity of magnitude 21; it then faded over a similar period. Barbary and colleagues report that the spectrum of light emitted from the object does not match known supernova types, and is dissimilar to any known phenomenon in the Sloan Digital Sky Survey database. The light in the blue region shows broad line features, while the red region shows continuous emission. The spectrum shows a handful of spectral lines, but when astronomers try to trace any one of them to an element the other lines fail to match up with any other known elements. Because of its uncommon spectrum, the team was not able to determine the distance to the object using standard redshift techniques; it is not even known whether the object is within or outside the Milky Way. Furthermore, no Milky Way star


id: shape-of-the-universe-20260505-0
file: data/en.wikipedia.org/wiki/Shape_of_the_universe-0.md
category: reference
title: Shape of the universe
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Shape_of_the_universe
date_saved: 2026-05-05T11:01:27.989865+00:00
instance: kb-cron
parent: shape-of-the-universe-20260505-0
summary:
Determination of the shape of the universe is a problem of physical cosmology. Observational evidence (BOOMERANG Project, MAXIMA, Planck, WMAP) indicates that the observable universe is spatially flat. It is unknown whether the universe is simply connected like euclidean space or multiply connected like a torus. == The observable universe == Human knowledge of the universe is restricted by the fact that any signal information from further than the cosmological horizon within the universe moving towards any position of human perception or telescope is non-available. == Possible shapes of the universe == Einstein stated, by the law of gravitation, heavy masses curve space-time. The curvature of spacetime is the same as the density parameter, represented with Ω (omega). The density parameter is the average density of the universe divided by the critical energy density, that is, the mass energy needed for a universe to be flat. Put another way, If Ω > 1, there is positive curvature. If Ω < 1, there is negative curvature. If Ω = 1, the universe is flat. Scientists could experimentally calculate Ω to determine the curvature two ways. One is to count all the mass–energy in the universe and take its average density, then


id: shape-of-the-universe-20260505-1
file: data/en.wikipedia.org/wiki/Shape_of_the_universe-1.md
category: reference
title: Shape of the universe
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Shape_of_the_universe
date_saved: 2026-05-05T11:01:27.989865+00:00
instance: kb-cron
parent: shape-of-the-universe-20260505-0
summary:
=== Curvature === The curvature of the universe places constraints on the topology. If the spatial geometry is spherical, i.e., possess positive curvature, the topology is compact. For a flat (zero curvature) or a hyperbolic (negative curvature) spatial geometry, the topology can be either compact or infinite. Many textbooks erroneously state that a flat or hyperbolic universe implies an infinite universe; however, the correct statement is that a flat universe that is also simply connected implies an infinite universe. The latest research shows that even the most powerful future experiments (like the SKA) will not be able to distinguish between a flat, open and closed universe if the true value of cosmological curvature parameter is smaller than 10−4. If the true value of the cosmological curvature parameter is larger than 10−3 we will be able to distinguish between these three models even now. Final results of the Planck mission, released in 2018, show the cosmological curvature parameter, 1 − Ω = ΩK = −Kc2/a2H2, to be 0.0007±0.0019, consistent with a flat universe. ==== Universe with zero curvature ==== A flat universe can have zero total energy. ==== Universe with positive curvature ==== Poincaré dodecahedral space is a positively curved space,


id: solar-corona-20260505-0
file: data/en.wikipedia.org/wiki/Solar_corona-0.md
category: reference
title: Solar corona
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_corona
date_saved: 2026-05-05T11:01:29.364493+00:00
instance: kb-cron
parent: solar-corona-20260505-0
summary:
The solar corona is the outermost layer of the Sun's atmosphere. It is a region filled with relatively hot, tenuous plasma that is structured by the solar magnetic field. The solar corona lies above the photosphere and chromosphere and extends out to the edge of the solar atmosphere where it merges with the solar wind. The chromosphere and corona are separated by a thin, highly dynamic transition region. The outer edge of solar atmosphere where the corona transitions into the solar wind is defined by the Alfvén surface which forms an irregularly shaped boundary around the Sun at heights ranging from about 10 to 20 solar radii (7000000 to 14000000 km) above the photosphere. Coronal light is typically obscured by diffuse sky radiation and glare from the solar disk, but can be easily seen by the naked eye during a total solar eclipse or with a specialized coronagraph. Spectroscopic measurements indicate strong ionization in the corona and a plasma temperature in excess of 1000000 kelvins, much hotter than the surface of the Sun. The solar corona is populated by structures such as prominences, coronal loops, and helmet streamers. == Observational history == In 1724, French-Italian astronomer Giacomo F. Maraldi recognized


id: solar-corona-20260505-1
file: data/en.wikipedia.org/wiki/Solar_corona-1.md
category: reference
title: Solar corona
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_corona
date_saved: 2026-05-05T11:01:29.364493+00:00
instance: kb-cron
parent: solar-corona-20260505-0
summary:
The K-corona (K for kontinuierlich, "continuous" in German) is from photospheric light Thomson scattering off free electrons in the corona. Doppler broadening of the scattered photospheric absorption lines spreads them so greatly as to completely obscure them, giving the spectral appearance of a continuum with no absorption lines. The F-corona (F for Fraunhofer) is from photospheric light scattering off dust particles located beyond about one solar radius above the photosphere. These dust particles are much slower than the electrons, so Doppler broadening is negligible. As a result, the Fraunhofer absorption lines observed in the photospheric spectrum are also observed in the F-corona spectrum. The F-corona extends to very high elongation angles from the Sun and merges with the zodiacal light. This white-light component of the coronal radiation is extremely faint relative to the photosphere. The maximum brightness ratio between the photosphere and the corona just above the visible limb is on the order of 10−6 and decreases to 10−9 within a solar diameter from the limb. Furthermore, the sky brightness can be more than three to five orders of magnitude larger than the coronal brightness, rendering the corona unobservable to the naked eye without a total solar eclipses. A small


id: solar-corona-20260505-2
file: data/en.wikipedia.org/wiki/Solar_corona-2.md
category: reference
title: Solar corona
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_corona
date_saved: 2026-05-05T11:01:29.364493+00:00
instance: kb-cron
parent: solar-corona-20260505-0
summary:
Active regions involve all the phenomena directly linked to the magnetic field, which occur at different heights above the Sun's surface: sunspots and faculae occur in the photosphere; spicules, Hα filaments and plages in the chromosphere; prominences in the chromosphere and transition region; and flares and coronal mass ejections (CME) happen in the corona and chromosphere. If flares are very violent, they can also perturb the photosphere and generate a Moreton wave. On the contrary, quiescent prominences are large, cool, dense structures which are observed as dark, "snake-like" Hα ribbons (appearing like filaments) on the solar disc. Their temperature is about 5000–8000K, and so they are usually considered as chromospheric features. In 2013, images from the High Resolution Coronal Imager revealed never-before-seen "magnetic braids" of plasma within the outer layers of these active regions. === Helmet streamers === Helmet streamers are large, cap-like coronal structures with long, pointed peaks that usually overlie sunspots and active regions. Coronal streamers are considered to be sources of the slow solar wind. === Bright points === Bright points are small active regions found on the solar disk. X-ray bright points were first detected on April 8, 1969, during a rocket flight. The fraction of


id: solar-corona-20260505-3
file: data/en.wikipedia.org/wiki/Solar_corona-3.md
category: reference
title: Solar corona
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_corona
date_saved: 2026-05-05T11:01:29.364493+00:00
instance: kb-cron
parent: solar-corona-20260505-0
summary:
An initial impulsive phase, whose duration is on the order of minutes, strong emissions of energy are often observed even in the microwaves, EUV wavelengths and in the hard X-ray frequencies. A maximum phase A decay phase, which can last several hours. Sometimes also a phase preceding the flare can be observed, usually called as "pre-flare" phase. === Coronal mass ejections === Often accompanying large solar flares and prominences are coronal mass ejections (CME). These are enormous emissions of coronal material and magnetic field that travel outward from the Sun at up to 3000 km/s, containing roughly 10 times the energy of the solar flare or prominence that accompanies them. Some larger CMEs can propel hundreds of millions of tons of material into interplanetary space at 600,000–2,000,000 miles per hour (970,000–3,220,000 km/h). == Physics == === Thermal conduction === In the corona thermal conduction occurs from the external hotter atmosphere towards the inner cooler layers. Responsible for the diffusion process of the heat are the electrons, which are much lighter than ions and move faster. When there is a magnetic field the thermal conductivity of the plasma becomes higher in the direction which is parallel to the field lines rather


id: solar-corona-20260505-4
file: data/en.wikipedia.org/wiki/Solar_corona-4.md
category: reference
title: Solar corona
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_corona
date_saved: 2026-05-05T11:01:29.364493+00:00
instance: kb-cron
parent: solar-corona-20260505-0
summary:
The coronal heating problem in solar physics relates to the question of why the temperature of the Sun's corona is millions of kelvins greater than the thousands of kelvins of the surface. Several theories have been proposed to explain this phenomenon, but it is still challenging to determine which is correct. The problem first emerged after the identification of unknown spectral lines in the solar spectrum with highly ionized iron and calcium atoms. The comparison of the coronal and the photospheric temperatures of 6000K, leads to the question of how the 200-times-hotter coronal temperature can be maintained. The problem is primarily concerned with how the energy is transported up into the corona and then converted into heat within a few solar radii. The high temperatures require energy to be carried from the solar interior to the corona by non-thermal processes, because the second law of thermodynamics prevents heat from flowing directly from the solar photosphere (surface), which is at about 5800K, to the much hotter corona at about 1 to 3 MK (parts of the corona can even reach 10MK). Between the photosphere and the corona, the thin region through which the temperature increases is known as the transition region.


id: solar-corona-20260505-5
file: data/en.wikipedia.org/wiki/Solar_corona-5.md
category: reference
title: Solar corona
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_corona
date_saved: 2026-05-05T11:01:29.364493+00:00
instance: kb-cron
parent: solar-corona-20260505-0
summary:
=== Wave heating theory === The wave heating theory, proposed in 1949 by Evry Schatzman, proposes that waves carry energy from the solar interior to the solar chromosphere and corona. The Sun is made of plasma rather than ordinary gas, so it supports several types of waves analogous to sound waves in air. The most important types of wave are magneto-acoustic waves and Alfvén waves. Magneto-acoustic waves are sound waves that have been modified by the presence of a magnetic field, and Alfvén waves are similar to ultra low frequency radio waves that have been modified by interaction with matter in the plasma. Both types of waves can be launched by the turbulence of granulation and super granulation at the solar photosphere, and both types of waves can carry energy for some distance through the solar atmosphere before turning into shock waves that dissipate their energy as heat. One problem with wave heating is delivery of the heat to the appropriate place. Magneto-acoustic waves cannot carry sufficient energy upward through the chromosphere to the corona, both because of the low pressure present in the chromosphere and because they tend to be reflected back to the photosphere. Alfvén waves can carry


id: solar-corona-20260505-6
file: data/en.wikipedia.org/wiki/Solar_corona-6.md
category: reference
title: Solar corona
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_corona
date_saved: 2026-05-05T11:01:29.364493+00:00
instance: kb-cron
parent: solar-corona-20260505-0
summary:
=== Spicules (type II) === For decades, researchers believed spicules could send heat into the corona. However, following observational research in the 1980s, it was found that spicule plasma did not reach coronal temperatures, and so the theory was discounted. As per studies performed in 2010 at the National Center for Atmospheric Research in Colorado, in collaboration with the Lockheed Martin's Solar and Astrophysics Laboratory (LMSAL) and the Institute of Theoretical Astrophysics of the University of Oslo, a new class of spicules (TYPE II) discovered in 2007, which travel faster (up to 100 km/s) and have shorter lifespans, can account for the problem. These jets insert heated plasma into the Sun's outer atmosphere. The Atmospheric Imaging Assembly on NASA's Solar Dynamics Observatory and NASA's Focal Plane Package for the Solar Optical Telescope on the Japanese Hinode satellite were used to test this hypothesis. The high spatial and temporal resolutions of the newer instruments reveal this coronal mass supply. According to analysis in 2011 by de Pontieu and colleagues, these observations reveal a one-to-one connection between plasma that is heated to millions of degrees and the spicules that insert this plasma into the corona. == See also == == References ==


id: tabby-s-star-20260505-0
file: data/en.wikipedia.org/wiki/Tabby's_Star-0.md
category: reference
title: Tabby's Star
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Tabby's_Star
date_saved: 2026-05-05T11:01:31.754034+00:00
instance: kb-cron
parent: tabby-s-star-20260505-0
summary:
Tabby's Star (designated as KIC 8462852 in the Kepler Input Catalog, and also known by the names Boyajian's Star and WTF(Where'sTheFlux?) Star) is a binary star in the constellation Cygnus approximately 1,470 light-years (450 parsecs) from Earth. The system is composed of an F-type main-sequence star and a red dwarf companion. Unusual light fluctuations of Tabby's Star, including up to a 22% dimming in brightness, were discovered by citizen scientists as part of the Planet Hunters project. The discovery was made from data collected by the Kepler space telescope, which observed changes in the brightness of distant stars to detect exoplanets. Several hypotheses have been proposed to explain the star's large irregular changes in brightness, but as of 2024, none of them fully explain all aspects of the resulting light curve. It has been suggested that it is an extraterrestrial megastructure, but evidence tends to discount this suggestion. In September 2019, astronomers reported that the observed dimmings of Tabby's Star may have been produced by fragments resulting from the disruption of an orphaned exomoon. Tabby's Star is not the only star that has large irregular dimmings; other such stars include young stellar objects called YSO dippers, which have different dimming


id: tabby-s-star-20260505-1
file: data/en.wikipedia.org/wiki/Tabby's_Star-1.md
category: reference
title: Tabby's Star
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Tabby's_Star
date_saved: 2026-05-05T11:01:31.754034+00:00
instance: kb-cron
parent: tabby-s-star-20260505-0
summary:
On 20 May 2017, Boyajian and her colleagues reported, via The Astronomer's Telegram, on an ongoing dimming event (named "Elsie") which possibly began on 14 May 2017. It was detected by the Las Cumbres Observatory Global Telescope Network, specifically by its telescope in Maui (LCO Maui). This was verified by the Fairborn Observatory (part of the N2K Consortium) in Southern Arizona (and later by LCO Canary Islands). Further optical and infrared spectroscopy and photometry were urgently requested, given the short duration of these events, which may be measured in days or weeks. Observations from multiple observers globally were coordinated, including polarimetry. Furthermore, the independent SETI projects Breakthrough Listen and Near-InfraRed Optical SETI (NIROSETI), both at Lick Observatory, continue to monitor the star. By the end of the three-day dimming event, a dozen observatories had taken spectra, with some astronomers having dropped their own projects to provide telescope time and resources. More generally the astronomical community was described as having gone "mildly bananas" over the opportunity to collect data in real-time on the unique star. The 2% dip event was named "Elsie" (a homophone of "LC", in reference to Las Cumbres and light curve). Initial spectra with FRODOSpec at the two-meter


id: tabby-s-star-20260505-2
file: data/en.wikipedia.org/wiki/Tabby's_Star-2.md
category: reference
title: Tabby's Star
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Tabby's_Star
date_saved: 2026-05-05T11:01:31.754034+00:00
instance: kb-cron
parent: tabby-s-star-20260505-0
summary:
== Luminosity == Observations of the luminosity of the star by the Kepler space telescope show small, frequent, non-periodic dips in brightness, along with two large recorded dips in brightness two years apart. The amplitude of the changes in the star's brightness, and the aperiodicity of the changes, mean that this star is of particular interest for astronomers. The star's changes in brightness are consistent with many small masses orbiting the star in "tight formation". The first major dip, on 5 March 2011, reduced the star's brightness by up to 15%, and the next 726 days later (on 28 February 2013) by up to 22%. (A third dimming, around 8%, occurred 48 days later.) In comparison, a planet the size of Jupiter would only obscure a star of this size by 1%, indicating that whatever is blocking light during the star's major dips is not a planet, but rather something covering up to half the width of the star. Due to the failure of two of Kepler's reaction wheels, the star's predicted 750-day dip around February 2015 was not recorded. The light dips do not exhibit an obvious pattern. In addition to the day-long dimmings, a study of a century's


id: tabby-s-star-20260505-3
file: data/en.wikipedia.org/wiki/Tabby's_Star-3.md
category: reference
title: Tabby's Star
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Tabby's_Star
date_saved: 2026-05-05T11:01:31.754034+00:00
instance: kb-cron
parent: tabby-s-star-20260505-0
summary:
One proposed explanation for the reduction in light is that it is due to a cloud of disintegrating comets orbiting the star elliptically. This scenario would assume that a planetary system around Tabby's Star has something similar to the Oort cloud and that gravity from a nearby star caused comets from said cloud to fall closer into the system, thereby obstructing the spectra of Tabby's Star. Evidence supporting this hypothesis includes an M-type red dwarf within 132 billion kilometers (885 AU) of Tabby's Star. The notion that disturbed comets from such a cloud could exist in high enough numbers to obscure 22% of the star's observed luminosity has been doubted. The smooth shallow ingress and sharp egress of some dimming events, as well as some symmetric triple dips, are difficult to explain with the comet scenario. Instead, a few asteroid-like bodies embedded in a dust cloud may better explain the star's light curve. Submillimetre-wavelength observations searching for farther-out cold dust in an asteroid belt akin to the Sun's Kuiper Belt suggest that a distant "catastrophic" planetary disruption explanation is unlikely; the possibility of a disrupted asteroid belt scattering comets into the inner system is still to be determined. === Younger


id: tabby-s-star-20260505-4
file: data/en.wikipedia.org/wiki/Tabby's_Star-4.md
category: reference
title: Tabby's Star
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Tabby's_Star
date_saved: 2026-05-05T11:01:31.754034+00:00
instance: kb-cron
parent: tabby-s-star-20260505-0
summary:
=== Intrinsic luminosity variations === The reddening observed during the deep dimming events of Tabby's Star is consistent with cooling of its photosphere. It does not require obscuration by dust. Such cooling could be produced by a decreased efficiency of heat transport caused e.g. by decreased effectiveness of convection due to the star's strong differential rotation, or by changes in its modes of heat transport if it is near the transition between radiative and convective heat transport. The "missing" heat flux is stored as a small increase of internal and potential energy. The possible location of this early F star near the boundary between radiative and convective transport seems to be supported by the finding that the star's observed brightness variations appear to fit the "avalanche statistics" known to occur in a system close to a phase-transition. "Avalanche statistics" with a self-similar or power-law spectrum are a universal property of complex dynamical systems operating close to a phase transition or bifurcation point between two different types of dynamical behavior. Such close-to-critical systems are often observed to exhibit behavior that is intermediate between "order" and "chaos". Three other stars in the Kepler Input Catalog likewise exhibit similar "avalanche statistics" in their


id: transient-lunar-phenomenon-20260505-0
file: data/en.wikipedia.org/wiki/Transient_lunar_phenomenon-0.md
category: reference
title: Transient lunar phenomenon
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Transient_lunar_phenomenon
date_saved: 2026-05-05T11:01:33.015357+00:00
instance: kb-cron
parent: transient-lunar-phenomenon-20260505-0
summary:
A transient lunar phenomenon (TLP) or lunar transient phenomenon (LTP) is a short-lived change in light, color or appearance on the surface of the Moon. The term was created by Patrick Moore in his co-authorship of NASA Technical Report R-277 Chronological Catalog of Reported Lunar Events, published in 1968. Claims of short-lived lunar phenomena go back at least 1,000 years, with some having been observed independently by multiple witnesses or reputable scientists. Nevertheless, the majority of transient lunar phenomenon reports are irreproducible and do not possess adequate control experiments that could be used to distinguish among alternative hypotheses to explain their origins. Most lunar scientists will acknowledge that transient events such as outgassing and impact cratering do occur over geologic time. The controversy lies in the frequency of such events. == Description of events == Reports of transient lunar phenomena range from foggy patches to permanent changes of the lunar landscape. Cameron classifies these as (1) gaseous, involving mists and other forms of obscuration, (2) reddish colorations, (3) green, blue or violet colorations, (4) brightenings, and (5) darkening. Two extensive catalogs of transient lunar phenomena exist, with the most recent tallying 2,254 events going back to the 6th century. Of


id: transient-lunar-phenomenon-20260505-1
file: data/en.wikipedia.org/wiki/Transient_lunar_phenomenon-1.md
category: reference
title: Transient lunar phenomenon
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Transient_lunar_phenomenon
date_saved: 2026-05-05T11:01:33.015357+00:00
instance: kb-cron
parent: transient-lunar-phenomenon-20260505-0
summary:
=== 1801–1900 === Between 1830 and 1840, the German astronomer Johann Heinrich von Mädler observed a strong reddish tint closely east of crater Lichtenberg in Oceanus Procellarum. See also Barcroft in 1940, Haas at a later date, Baum in 1951, and Hill in 1988. On November 24, 1865, Williams and two others observed for one hour and a half a distinct bright speck like an 8 magnitude star on the dark side near crater Carlini in Mare Imbrium. In 1866, the experienced lunar observer and mapmaker J. F. Julius Schmidt claimed that the Linné crater had changed its appearance. Based on drawings made earlier by J. H. Schröter, as well as personal observations and drawings made between 1841 and 1843, he stated that the crater "at the time of oblique illumination cannot at all be seen" (his emphasis), whereas at high illumination, it was visible as a bright spot. Based on repeat observations, he further stated that "Linné can never be seen under any illumination as a crater of the normal type" and that "a local change has taken place". Today, Linné is visible as a normal young impact crater with a diameter of about 1.5 miles (2.4 km). On


id: transient-lunar-phenomenon-20260505-2
file: data/en.wikipedia.org/wiki/Transient_lunar_phenomenon-2.md
category: reference
title: Transient lunar phenomenon
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Transient_lunar_phenomenon
date_saved: 2026-05-05T11:01:33.015357+00:00
instance: kb-cron
parent: transient-lunar-phenomenon-20260505-0
summary:
=== 1951–1960 === In 1951, Richard Myer Baum (1930–2017) observed the regions near crater Lichtenberg in Oceanus Procellarum and reported a rose-pink coloration which persisted for a time and then faded. See also J.H.Mädler between 1830 and 1840, Barcroft in 1940, and Hill in 1988. On November 15, 1953, Dr. Leon Stuart photographed a lunar flare at approximately 10 miles southeast of crater Pallas. The duration of the flare was 8 to 10 seconds. According to Bonnie Buratti, the coordinates of the impacted object are 3.88° Latitude / 357.71° Longitude. On May 11, 1954, Peter Cattermole observed the disappearance of the central mountains of crater Eratosthenes, although the surrounding detail remained clearly visible. In 1954, Patrick Moore detected curious ray-like features crossing crater Helmholtz. On June 25, 1955, mountaineer and amateur astronomer Valdemar Axel Firsoff observed a faint mist in crater Theophilus. On July 15, 1955, V.A.Firsoff observed crater Herodotus which had a 'pseudo central peak' casting a shadow. On January 16–17, 1956, Robert Miles of Woodland, Calif., noticed a flash of white or bright blue light east of Mare Crisium. On November 2, 1958, the Russian astronomer Nikolai A. Kozyrev observed an apparent half-hour "eruption" that took place on


id: transient-lunar-phenomenon-20260505-3
file: data/en.wikipedia.org/wiki/Transient_lunar_phenomenon-3.md
category: reference
title: Transient lunar phenomenon
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Transient_lunar_phenomenon
date_saved: 2026-05-05T11:01:33.015357+00:00
instance: kb-cron
parent: transient-lunar-phenomenon-20260505-0
summary:
=== 1971–1980 === During the Apollo 17 mission in December 1972, Lunar Module Pilot Harrison Schmitt observed a bright flash-like phenomenon north of crater Grimaldi while in orbit around the Moon (First Revolution, 21:11:09 GMT, December 10, 1972). While in orbit, Command Module Pilot Ronald Evans of Apollo 17 noticed a light flash eastward of Mare Orientale (14th Revolution, 22:28:27 GMT, December 11, 1972). In September 1973, the Dutch author of books on mysterious phenomena Hans van Kampen and a friend (Van Cleef) observed near crater Linné a bright point of light which was visible for almost two minutes. === 1981–1990 === On December 27, 1982, British Moon observer Harold Hill noticed the absence of the principal craterlet (Nasmyth A) on the floor of the crater Nasmyth. A similar phenomenon was noticed by P.Wade on December 8, 1981. On January 1, 1983, Harold Hill noticed an unusual bright appearance of craterlet Furnerius A near the pronounced crater Furnerius at the evening terminator. On January 29, 1983, several members of the British Astronomical Association (BAA) observed abnormal brightness and purplish coloration at the bowl shaped crater Torricelli B north-northeast of the pear shaped crater Torricelli in Sinus Asperitatis. On October 29,


id: transient-lunar-phenomenon-20260505-4
file: data/en.wikipedia.org/wiki/Transient_lunar_phenomenon-4.md
category: reference
title: Transient lunar phenomenon
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Transient_lunar_phenomenon
date_saved: 2026-05-05T11:01:33.015357+00:00
instance: kb-cron
parent: transient-lunar-phenomenon-20260505-0
summary:
Impact events are continually occurring on the lunar surface. The most common events are those associated with micrometeorites, as might be encountered during meteor showers. First witnessed in 1972 on three occasions by the crew of Apollo 17, impact flashes from such events have been detected from multiple and simultaneous Earth-based observations. Tables of impacts recorded by video cameras exist for years since 2005 many of which are associated with meteor showers. Furthermore, impact clouds were detected following the crash of ESA's SMART-1 spacecraft, India's Moon Impact Probe and NASA's LCROSS. Impact events leave a visible scar on the surface, and these could be detected by analyzing before and after photos of sufficiently high resolution. No impact craters formed between the Clementine (global resolution 100 metre, selected areas 7–20 metre) and SMART-1 (resolution 50 metre) missions have been identified. NELIOTA successfully observed a wide range of impacts. The observations took place from 2017 to 2023. During these years, 192 lunar impact flashes were detected, and the size and mass of the asteroids were also measured, as well as the temperature during the collisions and the size of the craters created. As a result, apart from completing its main goal, it


id: ultra-high-energy-cosmic-ray-20260505-0
file: data/en.wikipedia.org/wiki/Ultra-high-energy_cosmic_ray-0.md
category: reference
title: Ultra-high-energy cosmic ray
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ultra-high-energy_cosmic_ray
date_saved: 2026-05-05T11:01:34.246968+00:00
instance: kb-cron
parent: ultra-high-energy-cosmic-ray-20260505-0
summary:
In astroparticle physics, an ultra-high-energy cosmic ray (UHECR) is a cosmic ray with an energy greater than 1 EeV (1018 electronvolts, approximately 0.16 joules), far beyond both the rest mass and energies typical of other cosmic ray particles. The origin of these highest energy cosmic rays is not known. These particles are extremely rare; between 2004 and 2007, the initial runs of the Pierre Auger Observatory (PAO) detected 27 events with estimated arrival energies above 5.7×1019 eV, that is, about one such event every four weeks in the 3000 km2 (1200 mi2) area surveyed by the observatory. == Observational history == The first observation of a cosmic ray particle with an energy exceeding 1.0×1020 eV (16 J) was made by John Linsley and Livio Scarsi at the Volcano Ranch experiment in New Mexico in 1962. Cosmic ray particles with even higher energies have since been observed. Among them was the Oh-My-God particle observed by the University of Utah's Fly's Eye experiment on the evening of 15 October 1991 over Dugway Proving Ground, Utah. Its observation was shocking to astrophysicists, who estimated its energy at approximately 3.2×1020 eV (50 J)—essentially an atomic nucleus with kinetic energy equal to that of a


id: ultra-high-energy-cosmic-ray-20260505-1
file: data/en.wikipedia.org/wiki/Ultra-high-energy_cosmic_ray-1.md
category: reference
title: Ultra-high-energy cosmic ray
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ultra-high-energy_cosmic_ray
date_saved: 2026-05-05T11:01:34.246968+00:00
instance: kb-cron
parent: ultra-high-energy-cosmic-ray-20260505-0
summary:
=== Neutron stars === One suggested source of UHECR particles is their origination from neutron stars. In young neutron stars with spin periods of under 10 ms, the magnetohydrodynamic (MHD) forces from the quasi-neutral fluid of superconducting protons and electrons existing in a neutron superfluid accelerate iron nuclei to UHECR velocities. The neutron superfluid in rapidly rotating stars creates a magnetic field of 108 to 1011 teslas, at which point the neutron star is classified as a magnetar. This magnetic field is the strongest stable field in the observed universe and creates the relativistic MHD wind believed to accelerate iron nuclei remaining from the supernova to the necessary energy. Another hypothesized source of UHECRs from neutron stars is during neutron star to strange star combustion. This hypothesis relies on the assumption that strange matter is the ground state of matter, but has no experimental or observational data to support it. Due to the immense gravitational pressures from the neutron star, it is believed that small pockets of matter consisting of up, down, and strange quarks in equilibrium acting as a single hadron (as opposed to a number of Σ0 baryons). This will then combust the entire star to strange matter,


id: ultra-high-energy-cosmic-ray-20260505-2
file: data/en.wikipedia.org/wiki/Ultra-high-energy_cosmic_ray-2.md
category: reference
title: Ultra-high-energy cosmic ray
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ultra-high-energy_cosmic_ray
date_saved: 2026-05-05T11:01:34.246968+00:00
instance: kb-cron
parent: ultra-high-energy-cosmic-ray-20260505-0
summary:
== Further reading == Elbert, J. W.; Sommers, P. (1995). "In search of a source for the 320 EeV Fly's Eye cosmic ray". The Astrophysical Journal. 441 (1): 151–161. arXiv:astro-ph/9410069. Bibcode:1995ApJ...441..151E. doi:10.1086/175345. S2CID 15510276. Clay, R.; Dawson, B. (1997). Cosmic Bullets: High Energy Particles in Astrophysics. Perseus Books. ISBN 978-0-7382-0139-9. Seife, C. (2000). "Fly's Eye Spies Highs in Cosmic Rays' Demise". Science. 288 (5469): 1147–1149. doi:10.1126/science.288.5469.1147a. PMID 10841723. S2CID 117341691. The Pierre Auger Collaboration; Abreu; Aglietta; Aguirre; Allard; Allekotte; Allen; Allison; Alvarez; Alvarez-Muniz; Ambrosio; Anchordoqui; Andringa; Anzalone; Aramo; Argiro; Arisaka; Armengaud; Arneodo; Arqueros; Asch; Asorey; Assis; Atulugama; Aublin; Ave; Avila; Backer; Badagnani; et al. (2007). "Correlation of the Highest-Energy Cosmic Rays with Nearby Extragalactic Objects". Science. 318 (5852): 938–943. arXiv:0711.2256. Bibcode:2007Sci...318..938P. doi:10.1126/science.1151124. PMID 17991855. S2CID 118376969. == External links == The Highest Energy Particle Ever Recorded Archived 2009-08-15 at the Wayback Machine The details of the event from the official site of the Fly's Eye detector. John Walker's lively analysis of the 1991 event, published in 1994 Origin of energetic space particles pinpointed, by Mark Peplow for news@nature.com, published January 13, 2005. Saharan, Mohit. "Search for ultra-high energy neutrinos at the Pierre Auger Observatory" (PDF). NNV Annual Meeting 2022, Nikhef.


id: unidentified-infrared-emission-20260505-0
file: data/en.wikipedia.org/wiki/Unidentified_infrared_emission-0.md
category: reference
title: Unidentified infrared emission
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Unidentified_infrared_emission
date_saved: 2026-05-05T11:01:35.430261+00:00
instance: kb-cron
parent: unidentified-infrared-emission-20260505-0
summary:
The unidentified infrared emission (UIR or UIE) bands are infrared discrete emissions from circumstellar regions, interstellar media, star-forming regions and extragalactic objects for which the identity of the emitting materials is unknown. The main infrared features occur around 3.3, 6.2, 7.7, 8.6, 11.2, and 12.7 μm, although there are many other weak emission features within the ~ 5–19 μm spectral range. In the 1980s, astronomers discovered that the origin of the UIR emission bands is inherent in compounds made of aromatic C–H and C=C chemical bonds, and some went on to hypothesize that the materials responsible should be free-flying polycyclic aromatic hydrocarbon (PAH) molecules. This assignment was based on the observation that the carrier operates far from thermal equilibrium and should therefore be transiently excited by single-photon absorption, which was taken as indicative of a molecule rather than a bulk solid material. Data recorded with the ESA's Infrared Space Observatory and NASA's Spitzer Space Telescope have suggested that the UIR emission bands arise from compounds that are far more complex in composition and structure than PAH molecules. Moreover, the UIR bands follow a clear evolutionary spectral trend that is linked to the lifespan of the astronomical source; from the time


id: vvv-wit-07-20260505-0
file: data/en.wikipedia.org/wiki/VVV-WIT-07-0.md
category: reference
title: VVV-WIT-07
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/VVV-WIT-07
date_saved: 2026-05-05T11:01:36.622029+00:00
instance: kb-cron
parent: vvv-wit-07-20260505-0
summary:
VVV-WIT-07 is a unique variable star which presents a sequence of recurrent dimmings (Ks~14.35 – 16.164) with a possible deep eclipse in July 2012. The star, located in the Scorpius constellation about 23,000 ly (7,100 pc) away, is not a binary star, which would eliminate such a system from explaining the various observed dimmings. == Overview == The star was found by the "Vista Variables in the Via Lactea" (VVV) project, which is a survey of European Southern Observatory (ESO) variability of the innermost bulge of the Milky Way galaxy. The near-infrared spectra of VVV-WIT-07 appear without features, without prominent emission or absorption lines. The characteristics found in the light curve of VVV-WIT-07 (WIT refers to "What Is This?") are similar to those seen in J1407 (Mamajek's Object), a pre-MS K5 dwarf with a ring system that eclipses the star or, alternatively, to Tabby's star, an F3 IV/V star that shows irregular and aperiodic obscurations in its light curve. From 2010 to 2018, the star dimmed and brightened irregularly (v~14.35 – 16.164), and seemed similar to Tabby's star, except the light from VVV-WIT-07 dimmed by up to 80 percent, while Tabby's star faded by only about 20 percent. Another star,


id: wow-signal-20260505-0
file: data/en.wikipedia.org/wiki/Wow!_signal-0.md
category: reference
title: Wow! signal
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wow!_signal
date_saved: 2026-05-05T11:01:37.835016+00:00
instance: kb-cron
parent: wow-signal-20260505-0
summary:
The Wow! signal was a strong narrowband radio signal detected on August 15, 1977, by Ohio State University's Big Ear radio telescope in the United States, then used to support the search for extraterrestrial intelligence. The signal appeared to come from the direction of the constellation Sagittarius and bore expected hallmarks of extraterrestrial origin. Astronomer Jerry R. Ehman discovered the anomaly a few days later while reviewing the recorded data. On the computer printout, he circled the reading of the signal's intensity, "6EQUJ5", and wrote the comment "Wow!" beside it, leading to the event's widely used name. The entire signal sequence lasted for the full 72-second window during which Big Ear was able to observe it. Despite numerous follow-up searches and hypotheses (including brief consideration of reflections from space debris, interstellar scintillation, and comet hydrogen clouds), the signal has never recurred, and no explanation, terrestrial or otherwise, has been confirmed. While some researchers have suggested it could represent an extraterrestrial transmission, its single occurrence and lack of replication limit the strength of this interpretation. The Wow! signal has inspired targeted searches, scientific discussion about rare astrophysical phenomena, and references in popular culture. == Background == In a 1959 paper, Cornell


id: wow-signal-20260505-1
file: data/en.wikipedia.org/wiki/Wow!_signal-1.md
category: reference
title: Wow! signal
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wow!_signal
date_saved: 2026-05-05T11:01:37.835016+00:00
instance: kb-cron
parent: wow-signal-20260505-0
summary:
=== Time variation === At the time of the observation, the Big Ear radio telescope was only adjustable for altitude (or height above the horizon), and relied on the rotation of the Earth to scan across the sky. Given the speed of Earth's rotation and the spatial width of the telescope's observation window, the Big Ear could observe any given point for just 72 seconds. A continuous extraterrestrial signal, therefore, would be expected to register for exactly 72 seconds, and the recorded intensity of such a signal would display a gradual increase for the first 36 seconds—peaking at the center of the observation window—and then a gradual decrease as the telescope moved away from it. All these characteristics are present in the Wow! signal. == Celestial location == The precise location in the sky where the signal apparently originated is uncertain due to the design of the Big Ear telescope, which featured two feed horns, each receiving a beam from slightly different directions, while following Earth's rotation. The Wow! signal was detected in one beam but not in the other, and the data was processed in such a way that it is impossible to determine which of the two horns


id: wow-signal-20260505-2
file: data/en.wikipedia.org/wiki/Wow!_signal-2.md
category: reference
title: Wow! signal
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wow!_signal
date_saved: 2026-05-05T11:01:37.835016+00:00
instance: kb-cron
parent: wow-signal-20260505-0
summary:
== Searches for recurrence of the signal == Several attempts were made by Ehman and other astronomers to recover and identify the signal. The signal was expected to occur three minutes apart in each of the telescope's feed horns, but that did not happen. Ehman unsuccessfully searched for recurrences using Big Ear in the months after the detection. In 1987 and 1989, Robert H. Gray searched for the event using the META array at Oak Ridge Observatory, but did not detect it. In a July 1995 test of signal detection software to be used in its upcoming Project Argus, SETI League executive director [[H. Paul Shuch made several drift-scan observations of the Wow! signal's coordinates with a 12-meter radio telescope at the National Radio Astronomy Observatory in Green Bank, West Virginia, also achieving a null result. In 1995 and 1996, Gray again searched for the signal using the Very Large Array, which is significantly more sensitive than Big Ear. Gray and Simon Ellingsen later searched for recurrences of the event in 1999 using the 26-meter radio telescope at the University of Tasmania's Mount Pleasant Radio Observatory. Six 14-hour observations were made at positions in the vicinity, but nothing like the


id: avalon-explosion-20260505-0
file: data/en.wikipedia.org/wiki/Avalon_explosion-0.md
category: reference
title: Avalon explosion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Avalon_explosion
date_saved: 2026-05-05T11:01:40.553278+00:00
instance: kb-cron
parent: avalon-explosion-20260505-0
summary:
The Avalon explosion, named from the Precambrian faunal trace fossils discovered on the Avalon Peninsula in Newfoundland, eastern Canada, is a proposed evolutionary radiation of prehistoric animals about 575 million years ago in the Ediacaran period, with the Avalon explosion being one of three eras grouped in this time period. This evolutionary event is believed to have occurred some 33 million years earlier than the Cambrian explosion, which had been long thought to be when complex life started on Earth. Scientists are still unsure of the full extent behind the development of the Avalon explosion, which resulted in a rapid increase in metazoan biodiversity, including the first appearance of some extant infrakingdoms/superphyla such as cnidarians and bilaterians. Many of the Avalon explosion animals are sessile soft-bodied organisms living in deep marine environments, and the first stages of the Avalon explosion were observed through comparatively minimal species. == History == Charles Darwin predicted a time of ecological growth before the Cambrian Period, but there was no evidence to support it until the Avalon explosion was proposed in 2008 by Virginia Tech paleontologists after analysis of the morphological space change in several Ediacaran assemblages. The discovery suggests that the early evolution of


id: cambrian-explosion-20260505-0
file: data/en.wikipedia.org/wiki/Cambrian_explosion-0.md
category: reference
title: Cambrian explosion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cambrian_explosion
date_saved: 2026-05-05T11:01:41.804996+00:00
instance: kb-cron
parent: cambrian-explosion-20260505-0
summary:
The Cambrian explosion (also known as the Cambrian radiation or Cambrian diversification) is an interval of time beginning approximately 538.8 million years ago in the Cambrian period of the early Paleozoic, when a sudden radiation of complex life occurred and practically all major animal phyla started appearing in the fossil record. It lasted for about 13 to 25 million years and resulted in the divergence of most modern metazoan phyla. The event was accompanied by major diversification in other groups of organisms as well. Before early Cambrian diversification, most organisms were relatively simple, composed of individual cells or small multicellular organisms, occasionally organized into colonies. As the rate of diversification subsequently accelerated, the variety of life became much more complex and began to resemble that of today. Almost all present-day animal phyla appeared during this period, including the earliest chordates. == History and significance == The seemingly rapid appearance of fossils in the "Primordial Strata" was noted by William Buckland in the 1840s. Charles Darwin in his 1859 book On the Origin of Species discussed the then inexplicable lack of earlier fossils as one of the main difficulties for his theory of descent with slow modification through natural selection. The


id: cambrian-explosion-20260505-1
file: data/en.wikipedia.org/wiki/Cambrian_explosion-1.md
category: reference
title: Cambrian explosion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cambrian_explosion
date_saved: 2026-05-05T11:01:41.804996+00:00
instance: kb-cron
parent: cambrian-explosion-20260505-0
summary:
=== Dating the Cambrian === Radiometric dates for much of the Cambrian, obtained by analysis of radioactive elements contained within rocks, have only recently become available, and for only a few regions. Relative dating (A was before B) is often assumed sufficient for studying processes of evolution, but this, too, has been difficult, because of the problems involved in matching up rocks of the same age across different continents. Therefore, dates or descriptions of sequences of events should be regarded with some caution until better data becomes available. In 2004, the start of the Cambrian was dated to 542 Ma. In 2012, it was revised to 541 Ma then in 2022 it was changed again to 538.8 Ma. Some theory suggest Cambrian explosion occurred during the last stages of Gondwanan assembly, which is formed following Rodinia splitting, overlapped with the opening of the Iapetus Ocean between Laurentia and western Gondwana. The largest Cambrian faunal province is located around Gondwana, which extended from the low northern latitudes to the high southern latitudes, just short of the South Pole. By the middle and later parts of the Cambrian, continued rifting had sent the paleocontinents of Laurentia, Baltica and Siberia on their separate


id: cambrian-explosion-20260505-2
file: data/en.wikipedia.org/wiki/Cambrian_explosion-2.md
category: reference
title: Cambrian explosion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cambrian_explosion
date_saved: 2026-05-05T11:01:41.804996+00:00
instance: kb-cron
parent: cambrian-explosion-20260505-0
summary:
=== Phylogenetic techniques === Cladistics is a technique for working out the "family tree" of a set of organisms. It works by the logic that, if groups B and C have more similarities to each other than either has to group A, then B and C are more closely related to each other than either is to A. Characteristics that are compared may be anatomical, such as the presence of a notochord, or molecular, by comparing sequences of DNA or protein. The result of a successful analysis is a hierarchy of clades—groups whose members are believed to share a common ancestor. The cladistic technique is sometimes problematic, as some features, such as wings or camera eyes, evolved more than once, convergently—this must be taken into account in analyses. From the relationships, it may be possible to constrain the date that lineages first appeared. For instance, if fossils of B or C date to X million years ago and the calculated "family tree" says A was an ancestor of B and C, then A must have evolved more than X million years ago. It is also possible to estimate how long ago two living clades diverged—i.e. about how long ago their


id: cambrian-explosion-20260505-3
file: data/en.wikipedia.org/wiki/Cambrian_explosion-3.md
category: reference
title: Cambrian explosion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cambrian_explosion
date_saved: 2026-05-05T11:01:41.804996+00:00
instance: kb-cron
parent: cambrian-explosion-20260505-0
summary:
Changes in the abundance and diversity of some types of fossil have been interpreted as evidence for "attacks" by animals or other organisms. Stromatolites, stubby pillars built by colonies of microorganisms, are a major constituent of the fossil record from about 2,700 million years ago, but their abundance and diversity declined steeply after about 1,250 million years ago. This decline has been attributed to disruption by grazing and burrowing animals. Precambrian marine diversity was dominated by small fossils known as acritarchs. This term describes almost any small organic-walled fossil—from the egg cases of small metazoans to resting cysts of many different kinds of green algae. After appearing around 2,000 million years ago, acritarchs underwent a boom around 1,000 million years ago, increasing in abundance, diversity, size, complexity of shape, and especially size and number of spines. Their increasingly spiny forms in the last 1 billion years may indicate an increased need for defence against predation. Other groups of small organisms from the Neoproterozoic era also show signs of antipredator defenses. A consideration of taxon longevity appears to support an increase in predation pressure around this time. In general, the fossil record shows a very slow appearance of these lifeforms in


id: cambrian-explosion-20260505-4
file: data/en.wikipedia.org/wiki/Cambrian_explosion-4.md
category: reference
title: Cambrian explosion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cambrian_explosion
date_saved: 2026-05-05T11:01:41.804996+00:00
instance: kb-cron
parent: cambrian-explosion-20260505-0
summary:
Crustaceans, one of the four great modern groups of arthropods, are very rare throughout the Cambrian. Convincing crustaceans were once thought to be common in Burgess Shale-type biotas, but none of these individuals can be shown to fall into the crown group of "true crustaceans". The Cambrian record of crown-group crustaceans comes from microfossils. The Swedish Orsten horizons contain later Cambrian crustaceans, but only organisms smaller than 2 mm are preserved. This restricts the data set to juveniles and miniaturised adults. A more informative data source is the organic microfossils of the Mount Cap formation, Mackenzie Mountains, Canada. This late Early Cambrian assemblage (510 to 515 million years ago) consists of microscopic fragments of arthropods' cuticle, which is left behind when the rock is dissolved with hydrofluoric acid. The diversity of this assemblage is similar to that of modern crustacean faunas. Analysis of fragments of feeding machinery found in the formation shows that it was adapted to feed in a very precise and refined fashion. This contrasts with most other early Cambrian arthropods, which fed messily by shovelling anything they could get their feeding appendages on into their mouths. This sophisticated and specialised feeding machinery belonged to a large (about


id: cambrian-explosion-20260505-5
file: data/en.wikipedia.org/wiki/Cambrian_explosion-5.md
category: reference
title: Cambrian explosion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cambrian_explosion
date_saved: 2026-05-05T11:01:41.804996+00:00
instance: kb-cron
parent: cambrian-explosion-20260505-0
summary:
The Burgess Shale and similar lagerstätten preserve the soft parts of organisms, which provide a wealth of data to aid in the classification of enigmatic fossils. It often preserved complete specimens of organisms only otherwise known from dispersed parts, such as loose scales or isolated mouthparts. Further, the majority of organisms and taxa in these horizons are entirely soft-bodied, hence absent from the rest of the fossil record. Since a large part of the ecosystem is preserved, the ecology of the community can also be tentatively reconstructed. However, the assemblages may represent a "museum": a deep-water ecosystem that is evolutionarily "behind" the rapidly diversifying fauna of shallower waters. Because the lagerstätten provide a mode and quality of preservation that is virtually absent outside of the Cambrian, many organisms appear completely different from anything known from the conventional fossil record. This led early workers in the field to attempt to shoehorn the organisms into extant phyla; the shortcomings of this approach led later workers to erect a multitude of new phyla to accommodate all the oddballs. It has since been realised that most oddballs diverged from lineages before they established the phyla known today—slightly different designs, which were fated to perish


id: cambrian-explosion-20260505-6
file: data/en.wikipedia.org/wiki/Cambrian_explosion-6.md
category: reference
title: Cambrian explosion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cambrian_explosion
date_saved: 2026-05-05T11:01:41.804996+00:00
instance: kb-cron
parent: cambrian-explosion-20260505-0
summary:
== Validity == There is strong evidence for species of Cnidaria and Porifera existing in the Ediacaran and possible members of Porifera even before that during the Cryogenian. Bryozoans, once thought to not appear in the fossil record until after the Cambrian, are now known from strata of Cambrian Age 3 from Australia and South China. The fossil record as Darwin knew it seemed to suggest that the major metazoan groups appeared in a few million years of the early to mid-Cambrian, and even in the 1980s, this still appeared to be the case. However, evidence of Precambrian Metazoa is gradually accumulating. If the Ediacaran Kimberella was a mollusc-like protostome (one of the two main groups of coelomates), the protostome and deuterostome lineages must have split significantly before 550 million years ago (deuterostomes are the other main group of coelomates). Even if it is not a protostome, it is widely accepted as a bilaterian. Since fossils of rather modern-looking cnidarians (jellyfish-like organisms) have been found in the Doushantuo lagerstätte, the cnidarian and bilaterian lineages must have diverged well over 580 million years ago. Trace fossils and predatory borings in Cloudina shells provide further evidence of Ediacaran animals. Some fossils from


id: cambrian-explosion-20260505-7
file: data/en.wikipedia.org/wiki/Cambrian_explosion-7.md
category: reference
title: Cambrian explosion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cambrian_explosion
date_saved: 2026-05-05T11:01:41.804996+00:00
instance: kb-cron
parent: cambrian-explosion-20260505-0
summary:
==== Increase in oxygen levels ==== Earth's earliest atmosphere contained no free oxygen (O2); the oxygen that animals breathe today, both in the air and dissolved in water, is the product of billions of years of photosynthesis. Cyanobacteria were the first organisms to evolve the ability to photosynthesize, introducing a steady supply of oxygen into the environment. Initially, oxygen levels did not increase substantially in the atmosphere. The oxygen quickly reacted with iron and other minerals in the surrounding rock and ocean water. Once a saturation point was reached for the reactions in rock and water, oxygen was able to exist as a gas in its diatomic form. Oxygen levels in the atmosphere increased substantially afterward. As a general trend, the concentration of oxygen in the atmosphere has risen gradually over about the last 2.5 billion years. Oxygen levels seem to have a positive correlation with diversity in eukaryotes well before the Cambrian period. The last common ancestor of all extant eukaryotes is thought to have lived around 1.8 billion years ago. Around 800 million years ago, there was a notable increase in the complexity and number of eukaryotes species in the fossil record. Before the spike in diversity, eukaryotes


id: cambrian-explosion-20260505-8
file: data/en.wikipedia.org/wiki/Cambrian_explosion-8.md
category: reference
title: Cambrian explosion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cambrian_explosion
date_saved: 2026-05-05T11:01:41.804996+00:00
instance: kb-cron
parent: cambrian-explosion-20260505-0
summary:
A range of theories are based on the concept that minor modifications to animals' development as they grow from embryo to adult may have been able to cause very large changes in the final adult form. The Hox genes, for example, control which organs individual regions of an embryo will develop into. For instance, if a certain Hox gene is expressed, a region will develop into a limb; if a different Hox gene is expressed in that region (a minor change), it could develop into an eye instead (a phenotypically major change). Such a system allows a large range of disparity to appear from a limited set of genes, but such theories linking this with the explosion struggle to explain why the origin of such a development system should by itself lead to increased diversity or disparity. Evidence of Precambrian metazoans combines with molecular data to show that much of the genetic architecture that could feasibly have played a role in the explosion was already well established by the Cambrian. This apparent paradox is addressed in a theory that focuses on the physics of development. It is proposed that the emergence of simple multicellular forms provided a changed context and


id: cambrian-explosion-20260505-9
file: data/en.wikipedia.org/wiki/Cambrian_explosion-9.md
category: reference
title: Cambrian explosion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cambrian_explosion
date_saved: 2026-05-05T11:01:41.804996+00:00
instance: kb-cron
parent: cambrian-explosion-20260505-0
summary:
==== Increase in size and diversity of planktonic animals ==== Geochemical evidence strongly indicates that the total mass of plankton has been similar to modern levels since early in the Proterozoic. Before the start of the Cambrian, their corpses and droppings were too small to fall quickly towards the seabed, since their drag was about the same as their weight. This meant they were destroyed by scavengers or by chemical processes before they reached the sea floor. Mesozooplankton are plankton of a larger size. Early Cambrian specimens filtered microscopic plankton from the seawater. These larger organisms would have produced droppings and ultimately corpses large enough to fall fairly quickly. This provided a new supply of energy and nutrients to the mid-levels and bottoms of the seas, which opened up a new range of possible ways of life. If any of these remains sank uneaten to the sea floor they could be buried; this would have taken some carbon out of circulation, resulting in an increase in the concentration of breathable oxygen in the seas (carbon readily combines with oxygen). The initial herbivorous mesozooplankton were probably larvae of benthic (seafloor) animals. A larval stage was probably an evolutionary innovation driven by


id: cambrian-explosion-20260505-10
file: data/en.wikipedia.org/wiki/Cambrian_explosion-10.md
category: reference
title: Cambrian explosion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cambrian_explosion
date_saved: 2026-05-05T11:01:41.804996+00:00
instance: kb-cron
parent: cambrian-explosion-20260505-0
summary:
== Uniqueness of the early Cambrian biodiversification == The "Cambrian explosion" can be viewed as two waves of metazoan expansion into empty niches: first, a coevolutionary rise in diversity as animals explored niches on the Ediacaran sea floor, followed by a second expansion in the early Cambrian as they became established in the water column. The rate of diversification seen in the Cambrian phase of the explosion is unparalleled among marine animals: it affected all metazoan clades of which Cambrian fossils have been found. Later radiations, such as those of fish in the Silurian and Devonian periods, involved fewer taxa, mainly with very similar body plans. Although the recovery from the Permian-Triassic extinction started with about as few animal species as the Cambrian explosion, the recovery produced far fewer significantly new types of animals. Whatever triggered the early Cambrian diversification opened up an exceptionally wide range of previously unavailable ecological niches. When these were all occupied, limited space existed for such wide-ranging diversifications to occur again, because strong competition existed in all niches and incumbents usually had the advantage. If a wide range of empty niches had continued, clades would be able to continue diversifying and become disparate enough for


id: extraterrestrial-life-20260505-0
file: data/en.wikipedia.org/wiki/Extraterrestrial_life-0.md
category: reference
title: Extraterrestrial life
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Extraterrestrial_life
date_saved: 2026-05-05T11:01:43.119211+00:00
instance: kb-cron
parent: extraterrestrial-life-20260505-0
summary:
Extraterrestrial life, or alien life (colloquially aliens), is life that originates from another world rather than on Earth. No extraterrestrial life has yet been scientifically or conclusively detected. Such life might range from simple forms such as prokaryotes to intelligent beings, possibly bringing forth civilizations that might be far more, or far less, advanced than humans. The Drake equation speculates about the existence of sapient life elsewhere in the universe. The science of extraterrestrial life is known as astrobiology. Speculation about inhabited worlds beyond Earth dates back to antiquity. Early Christian writers, including Augustine, discussed ideas from thinkers like Democritus and Epicurus about countless worlds in the vast universe. Pre-modern writers typically assumed extraterrestrial "worlds" were inhabited by living beings. William Vorilong, in the 15th century, acknowledged the possibility Jesus could have visited extraterrestrial worlds to redeem their inhabitants. In 1440, Nicholas of Cusa suggested Earth is a "brilliant star"; he theorized that all celestial bodies, even the Sun, could host life. Descartes wrote that there were no means to prove the stars were not inhabited by "intelligent creatures", but their existence was a matter of speculation. In comparison to the life-abundant Earth, the vast majority of intrasolar and extrasolar


id: extraterrestrial-life-20260505-1
file: data/en.wikipedia.org/wiki/Extraterrestrial_life-1.md
category: reference
title: Extraterrestrial life
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Extraterrestrial_life
date_saved: 2026-05-05T11:01:43.119211+00:00
instance: kb-cron
parent: extraterrestrial-life-20260505-0
summary:
Using Big Bang models for the timeline of the universe, it was too hot for life for the first 15 million years and the elements of organic life, created through stellar fusion, did not exist until at least 50 million years. The first organic compounds may have formed in the protoplanetary disk of dust grains that would eventually create rocky planets like Earth. Although Earth was in a molten state after its birth and may have burned any organics that fell on it, it would have been more receptive once it cooled down. Once the right conditions on Earth were met, life started by a chemical process known as abiogenesis. During most of its stellar evolution, stars combine hydrogen nuclei to make helium nuclei by stellar fusion, and the comparatively lighter weight of helium allows the star to release the extra energy. The process continues until the star uses all of its available fuel, with the speed of consumption being related to the size of the star. During its last stages, stars start combining helium nuclei to form carbon nuclei. The larger stars can further combine carbon nuclei to create oxygen and silicon, oxygen into neon and sulfur, and so


id: extraterrestrial-life-20260505-2
file: data/en.wikipedia.org/wiki/Extraterrestrial_life-2.md
category: reference
title: Extraterrestrial life
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Extraterrestrial_life
date_saved: 2026-05-05T11:01:43.119211+00:00
instance: kb-cron
parent: extraterrestrial-life-20260505-0
summary:
Life in the cosmos beyond Earth has never been observed, but it is expected. The hypothesis of ubiquitous extraterrestrial life relies on three main ideas. The first one, the size of the universe, allows for plenty of planets to have a similar habitability to Earth, and the age of the universe gives enough time for a long process analog to the history of Earth to happen there. The second is that the substances that make life, such as carbon and water, are ubiquitous in the universe. The third is that the physical laws are universal, which means that the forces that would facilitate or prevent the existence of life would be the same ones as on Earth. According to this argument, made by scientists such as Carl Sagan and Stephen Hawking, it would be improbable for life not to exist somewhere else other than Earth. This argument is embodied in the Copernican principle, which states that Earth does not occupy a unique position in the Universe, and the mediocrity principle, which states that there is nothing special about life on Earth. Other authors consider instead that life in the cosmos, or at least multicellular life, may actually be rare. The


id: extraterrestrial-life-20260505-3
file: data/en.wikipedia.org/wiki/Extraterrestrial_life-3.md
category: reference
title: Extraterrestrial life
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Extraterrestrial_life
date_saved: 2026-05-05T11:01:43.119211+00:00
instance: kb-cron
parent: extraterrestrial-life-20260505-0
summary:
If extraterrestrial life exists, it could range from simple microorganisms and multicellular organisms similar to animals or plants, to complex alien intelligences akin to humans. When scientists talk about extraterrestrial life, they consider all those types. Although it is possible that extraterrestrial life may have other configurations, scientists use the hierarchy of lifeforms from Earth for simplicity, as it is the only one known to exist. The first basic requirement for life is an environment with non-equilibrium thermodynamics, which means that the thermodynamic equilibrium must be broken by a source of energy. The traditional sources of energy in the cosmos are the stars, such as for life on Earth, which depends on the energy of the sun. However, there are other alternative energy sources, such as volcanoes, plate tectonics, and hydrothermal vents. There are ecosystems on Earth in deep areas of the ocean that do not receive sunlight, and take energy from black smokers instead. Magnetic fields and radioactivity have also been proposed as sources of energy, although they would be less efficient ones. Life on Earth requires water in a liquid state as a solvent in which biochemical reactions take place. It is highly unlikely that an abiogenesis process


id: extraterrestrial-life-20260505-4
file: data/en.wikipedia.org/wiki/Extraterrestrial_life-4.md
category: reference
title: Extraterrestrial life
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Extraterrestrial_life
date_saved: 2026-05-05T11:01:43.119211+00:00
instance: kb-cron
parent: extraterrestrial-life-20260505-0
summary:
=== Harsh environmental conditions on Earth harboring life === It is common knowledge that the conditions on other planets in the solar system, in addition to the many galaxies outside of the Milky Way galaxy, are very harsh and seem to be too extreme to harbor any life. The environmental conditions on these planets can have intense UV radiation paired with extreme temperatures, lack of water, and much more that can lead to conditions that don't seem to favor the creation or maintenance of extraterrestrial life. However, there has been much historical evidence that some of the earliest and most basic forms of life on Earth originated in some extreme environments that seem unlikely to have harbored life at least at one point in Earth's history. Fossil evidence as well as many historical theories backed up by years of research and studies have marked environments like hydrothermal vents or acidic hot springs as some of the first places that life could have originated on Earth. These environments can be considered extreme when compared to the typical ecosystems that the majority of life on Earth now inhabit, as hydrothermal vents are scorching hot due to the magma escaping from the Earth's


id: extraterrestrial-life-20260505-5
file: data/en.wikipedia.org/wiki/Extraterrestrial_life-5.md
category: reference
title: Extraterrestrial life
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Extraterrestrial_life
date_saved: 2026-05-05T11:01:43.119211+00:00
instance: kb-cron
parent: extraterrestrial-life-20260505-0
summary:
The Solar System has a wide variety of planets, dwarf planets, and moons, and each one is studied for its potential to host life. Each one has its own specific conditions that may benefit or harm life. So far, the only lifeforms found are those from Earth. No extraterrestrial intelligence other than humans exists or has ever existed within the Solar System. Astrobiologist Mary Voytek points out that it would be unlikely to find large ecosystems, as they would have already been detected by now. The inner Solar System is likely devoid of life. However, Venus is still of interest to astrobiologists, as it is a terrestrial planet that was likely similar to Earth in its early stages and developed in a different way. There is a greenhouse effect, the surface is the hottest in the Solar System, sulfuric acid clouds, all surface liquid water is lost, and it has a thick carbon-dioxide atmosphere with huge pressure. Comparing both helps to understand the precise differences that lead to beneficial or harmful conditions for life. And despite the conditions against life on Venus, there are suspicions that microbial life-forms may still survive in high-altitude clouds. Mars is a cold and almost


id: extraterrestrial-life-20260505-6
file: data/en.wikipedia.org/wiki/Extraterrestrial_life-6.md
category: reference
title: Extraterrestrial life
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Extraterrestrial_life
date_saved: 2026-05-05T11:01:43.119211+00:00
instance: kb-cron
parent: extraterrestrial-life-20260505-0
summary:
Scientists search for biosignatures within the Solar System by studying planetary surfaces and examining meteorites. Some claim to have identified evidence that microbial life has existed on Mars. In 1996, a controversial report stated that structures resembling nanobacteria were discovered in a meteorite, ALH84001, formed of rock ejected from Mars. Although all the unusual properties of the meteorite were eventually explained as the result of inorganic processes, the controversy over its discovery laid the groundwork for the development of astrobiology. An experiment on the two Viking Mars landers reported gas emissions from heated Martian soil samples that some scientists argue are consistent with the presence of living microorganisms. Lack of corroborating evidence from other experiments on the same samples suggests that a non-biological reaction is a more likely hypothesis. In February 2005 NASA scientists reported they may have found some evidence of extraterrestrial life on Mars. The two scientists, Carol Stoker and Larry Lemke of NASA's Ames Research Center, based their claim on methane signatures found in Mars's atmosphere resembling the methane production of some forms of primitive life on Earth, as well as on their own study of primitive life near the Rio Tinto river in Spain. NASA officials


id: extraterrestrial-life-20260505-7
file: data/en.wikipedia.org/wiki/Extraterrestrial_life-7.md
category: reference
title: Extraterrestrial life
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Extraterrestrial_life
date_saved: 2026-05-05T11:01:43.119211+00:00
instance: kb-cron
parent: extraterrestrial-life-20260505-0
summary:
Although most searches are focused on the biology of extraterrestrial life, an extraterrestrial intelligence capable enough to develop a civilization may be detectable by other means as well. Technology may generate technosignatures, effects on the native planet that may not be caused by natural causes. There are three main types of techno-signatures considered: interstellar communications, effects on the atmosphere, and planetary-sized structures such as Dyson spheres. Organizations such as the SETI Institute search the cosmos for potential forms of communication. They started with radio waves, and now search for laser pulses as well. The challenge for this search is that there are natural sources of such signals as well, such as gamma-ray bursts and supernovae, and the difference between a natural signal and an artificial one would be in its specific patterns. Astronomers intend to use artificial intelligence for this, as it can manage large amounts of data and is devoid of biases and preconceptions. Besides, even if there is an advanced extraterrestrial civilization, there is no guarantee that it is transmitting radio communications in the direction of Earth. The length of time required for a signal to travel across space means that a potential answer may arrive decades or


id: extraterrestrial-life-20260505-8
file: data/en.wikipedia.org/wiki/Extraterrestrial_life-8.md
category: reference
title: Extraterrestrial life
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Extraterrestrial_life
date_saved: 2026-05-05T11:01:43.119211+00:00
instance: kb-cron
parent: extraterrestrial-life-20260505-0
summary:
The modern concept of extraterrestrial life is based on assumptions that were not commonplace during the early days of astronomy. The first explanations for the celestial objects seen in the night sky were based on mythology. Scholars from Ancient Greece were the first to consider that the universe is inherently understandable and rejected explanations based on supernatural incomprehensible forces, such as the myth of the Sun being pulled across the sky in the chariot of Apollo. They had not developed the scientific method yet and based their ideas on pure thought and speculation, but they developed precursor ideas to it, such as that explanations had to be discarded if they contradict observable facts. The discussions of those Greek scholars established many of the pillars that would eventually lead to the idea of extraterrestrial life, such as Earth being round and not flat. The cosmos was first structured in a geocentric model that considered that the sun and all other celestial bodies revolve around Earth. However, they did not consider them as worlds. In Greek understanding, the world was composed by both Earth and the celestial objects with noticeable movements. Anaximander thought that the cosmos was made from apeiron, a substance


id: extraterrestrial-life-20260505-9
file: data/en.wikipedia.org/wiki/Extraterrestrial_life-9.md
category: reference
title: Extraterrestrial life
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Extraterrestrial_life
date_saved: 2026-05-05T11:01:43.119211+00:00
instance: kb-cron
parent: extraterrestrial-life-20260505-0
summary:
By the time of the late Middle Ages there were many known inaccuracies in the geocentric model, but it was kept in use because naked eye observations provided limited data. Nicolaus Copernicus started the Copernican Revolution by proposing that the planets revolve around the sun rather than Earth. His proposal had little acceptance at first because, as he kept the assumption that orbits were perfect circles, his model led to as many inaccuracies as the geocentric one. Tycho Brahe improved the available data with naked-eye observatories, which worked with highly complex sextants and quadrants. Tycho could not make sense of his observations, but Johannes Kepler did: orbits were not perfect circles, but ellipses. This knowledge benefited the Copernican model, which worked now almost perfectly. The invention of the telescope a short time later, perfected by Galileo Galilei, clarified the final doubts, and the paradigm shift was completed. Under this new understanding, the notion of extraterrestrial life became feasible: if Earth is but just a planet orbiting around a star, there may be planets similar to Earth elsewhere. The astronomical study of distant bodies also proved that physical laws are the same elsewhere in the universe as on Earth, with nothing


