English: NASA Image of the day. Lyman Alpha absorption comes from ambient gas in the universe between us and distant quasars. This is a simulation of what clouds could've looked like at z=3
We live in a forest. Strewn throughout the universe are "trees" of hydrogen gas that absorb light from distant objects. These gas clouds leave numerous absorption lines in a distant quasar's spectra, together called the Lyman-alpha forest. Distant quasars appear to be absorbed by many more Lyman-alpha clouds than nearby quasars, indicating a Lyman-alpha thicket early in our universe. The above image depicts one possible computer realization of how Lyman-alpha clouds were distributed at a redshift of 3. Each side of the box measures 30 million light-years across. Much remains unknown about the Lyman-alpha forest, including the real geometry and extent of the clouds, and why there are so many fewer clouds today.
The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies. These are not necessarily in the public domain.
The SOHO (ESA & NASA) joint project implies that all materials created by its probe are copyrighted and require permission for commercial non-educational use. [2]
NASA Image of the day. Can be found at https://apod.nasa.gov/apod/ap001112.html Lyman Alpha absorption comes from ambient gas in the universe between us and distant quasars. This is a simulation of what clouds could've looked like at z=3
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