kb/data/en.wikipedia.org/wiki/Astroecology-1.md

title	chunk	source	category	tags	date_saved	instance
Astroecology	2/2	https://en.wikipedia.org/wiki/Astroecology	reference	science, encyclopedia	2026-05-05T07:17:12.052454+00:00	kb-cron

Equation 3:

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{\displaystyle BIOTA={\frac {M_{biomass}(0)}{k}}}

For example, if 0.01% of the biomass is lost per year, then the time-integrated BIOTA will be 10,000

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{\displaystyle M_{biomass}(0)}

. For the 6·1020 kg biomass constructed from asteroid resources, this yields 6·1024 kg-years of BIOTA in the Solar System. Even with this small rate of loss, life in the Solar System would disappear in a few hundred thousand years, and the potential total time-integrated BIOTA of 3·1030 kg-years under the main-sequence Sun would decrease by a factor of 5·105, although a still substantial population of 1.2·1012 biomass-supported humans could exist through the habitable lifespan of the Sun. The integrated biomass can be maximized by minimizing its rate of dissipation. If this rate can be reduced sufficiently, all the constructed biomass can last for the duration of the habitat and it pays to construct the biomass as fast as possible. However, if the rate of dissipation is significant, the construction rate of the biomass and its steady-state amounts may be reduced allowing a steady-state biomass and population that lasts throughout the lifetime of the habitat. An issue that arises is whether we should build immense amounts of life that decays fast, or smaller, but still large, populations that last longer. Life-centered biotic ethics suggests that life should last as long as possible.

== Galactic ecology == If life reaches galactic proportions, technology should be able to access all of the materials resources, and sustainable life will be defined by the available energy. The maximum amount of biomass about any star is then determined by the energy requirements of the biomass and by the luminosity of the star. For example, if 1 kg biomass needs 100 Watts, we can calculate the steady-state amounts of biomass that can be sustained by stars with various energy outputs. These amounts are multiplied by the life-time of the star to calculate the time-integrated BIOTA over the life-time of the star. Using similar projections, the potential amounts of future life can then be quantified. For the Solar System from its origins to the present, the current 1015 kg biomass over the past four billion years gives a time-integrated biomass (BIOTA) of 4·1024 kg-years. In comparison, carbon, nitrogen, phosphorus and water in the 1022 kg asteroids allows 6·1020 kg biomass that can be sustained with energy for the 5 billion future years of the Sun, giving a BIOTA of 3·1030 kg-years in the Solar System and 3·1039 kg-years about 1011 stars in the galaxy. Materials in comets could give biomass and time-integrated BIOTA a hundred times larger. The Sun will then become a white dwarf star, radiating 1015 Watts that sustains 1e13 kg biomass for an immense hundred million trillion (1020) years, contributing a time-integrated BIOTA of 1033 years. The 1012 white dwarfs that may exist in the galaxy during this time can then contribute a time-integrated BIOTA of 1045 kg-years. Red dwarf stars with luminosities of 1023 Watts and life-times of 1013 years can contribute 1034 kg-years each, and 1012 red dwarfs can contribute 1046 kg-years, while brown dwarfs can contribute 1039 kg-years of time-integrated biomass (BIOTA) in the galaxy. In total, the energy output of stars during 1020 years can sustain a time-integrated biomass of about 1045 kg-years in the galaxy. This is one billion trillion (1020) times more life than has existed on the Earth to date. In the universe, stars in 1011 galaxies could then sustain 1057 kg-years of life.

== Directed panspermia ==

The astroecology results above suggest that humans can expand life in the galaxy through space travel or directed panspermia. The amounts of possible life that can be established in the galaxy, as projected by astroecology, are immense. These projections are based on information about 15 billion past years since the Big Bang, but the habitable future is much longer, spanning trillions of eons. Therefore, physics, astroeclogy resources, and some cosmological scenarios may allow organized life to last, albeit at an ever slowing rate, indefinitely. These prospects may be addressed by the long-term extension of astroecology as cosmoecology.

== See also ==

Cosmology Meteorites

== References ==

== External links == Astro-Ecology / Science of expanding life in space AstroEthics / Ethics of expanding life in space Panspermia-Society / Science and ethics of expanding life in space