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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Cosmic Background Explorer | 4/4 | https://en.wikipedia.org/wiki/Cosmic_Background_Explorer | reference | science, encyclopedia | 2026-05-05T12:47:58.679749+00:00 | kb-cron |
On top of the findings DIRBE had on galaxies, it also made two other significant contributions to science. The DIRBE instrument was able to conduct studies on interplanetary dust (IPD) and determine if its origin was from asteroid or cometary particles. The DIRBE data collected at 12, 25, 50 and 100 μm were able to conclude that grains of asteroidal origin populate the IPD bands and the smooth IPD cloud. The second contribution DIRBE made was a model of the Galactic disk as seen edge-on from our position. According to the model, if the Sun is 8.6 kpc from the Galactic Center, then it is 15.6% above the midplane of the disk, which has a radial and vertical scale lengths of 2.64 and 0.333 kpc, respectively, and is warped in a way consistent with the HI layer. There is also no indication of a thick disk. To create this model, the IPD had to be subtracted out of the DIRBE data. It was found that this cloud, which as seen from Earth is Zodiacal light, was not centered on the Sun, as previously thought, but on a place in space a few million kilometers away. This is due to the gravitation influence of Saturn and Jupiter.
=== Cosmological implications === In addition to the science results detailed in the last section, there are numerous cosmological questions left unanswered by COBE's results. A direct measurement of the extragalactic background light (EBL) can also provide important constraints on the integrated cosmological history of star formation, metal and dust production, and the conversion of starlight into infrared emissions by dust. By looking at the results from DIRBE and FIRAS in the 140 to 5000 μm we can detect that the integrated EBL intensity is ≈16 nW/(m2·sr). This is consistent with the energy released during nucleosynthesis and constitutes about 20–50% of the total energy released in the formation of helium and metals throughout the history of the universe. Attributed only to nuclear sources, this intensity implies that more than 5–15% of the baryonic mass density implied by Big Bang nucleosynthesis analysis has been processed in stars to helium and heavier elements. There were also significant implications into star formation. COBE observations provide important constraints on the cosmic star formation rate and help us calculate the EBL spectrum for various star formation histories. Observation made by COBE require that star formation rate at redshifts of z ≈ 1.5 to be larger than that inferred from UV-optical observations by a factor of 2. This excess stellar energy must be mainly generated by massive stars in yet - undetected dust enshrouded galaxies or extremely dusty star-forming regions in observed galaxies. The exact star formation history cannot unambiguously be resolved by COBE and further observations must be made in the future. On 30 June 2001, NASA launched a follow-up mission to COBE led by DMR Deputy Principal Investigator Charles L. Bennett. The Wilkinson Microwave Anisotropy Probe has clarified and expanded upon COBE's accomplishments. Following WMAP, the European Space Agency's probe, Planck has continued to increase the resolution at which the background has been mapped.
== Popular culture == The Cosmic Background Explorer satellite appeared twice in the season 1 episode of Young Sheldon called "Gluons, Guacamole, and the Color Purple", where a young Sheldon Lee Cooper daydreams of helping NASA save the satellite from crashing back to Earth.
== See also ==
9997 COBE, a minor planet named after the experiment. S150 Galactic X-Ray Mapping Wilkinson Microwave Anisotropy Probe
== References ==
== Sources == Arny, Thomas T. (2002). Explorations: An Introduction to Astronomy (3rd ed.). Dubuque, Iowa: McGraw-Hill. ISBN 978-0-07-241593-3. Liddle, Andrew R.; Lyth, David H. (March 1993) [August 1992]. "The Cold Dark Matter Density Perturbation". Physics Reports. 231 (1–2). Elsevier (published August 1993): 1–105. arXiv:astro-ph/9303019. Bibcode:1993PhR...231....1L. doi:10.1016/0370-1573(93)90114-S. S2CID 119084975. Odenwald, Sten; Newmark, Jeffrey; Smoot, George (6 October 1995). "A Study of External Galaxies Detected by the COBE Diffuse Infrared Background Experiment". The Astrophysical Journal. 500 (2). American Astronomical Society (published 20 June 1998): 554–568. arXiv:astro-ph/9610238. Bibcode:1998ApJ...500..554O. doi:10.1086/305737. ISSN 0004-637X. S2CID 18799050.
== Further reading == Mather, John C.; Boslough, John (1996). The Very First Light: The True Inside Story of the Scientific Journey Back to the Dawn of the Universe. New York: BasicBooks. ISBN 0-465-01575-1. Smoot, George; Davidson, Keay (1993). Wrinkles in Time. New York: William Morrow. ISBN 0-688-12330-9. LCCN 93008500. OCLC 28215032. OL 1400708M. WMAP
== External links ==
NASA's website on COBE NASA informational video prior to COBE launch COBE Mission Profile by NASA's Solar System Exploration APOD picture of the COBE dipole, showing the 600 km/s motion of the Earth relative to the cosmic background radiation Cosmic Background Explorer article from Scholarpedia