On a scale that’s hard to fathom, the universe is made up of a “
cosmic web” of hydrogen filaments that feed and form galaxies. Now, astronomers have made the first direct observations of light from this web, by staring at a patch of sky with a powerful deep-field telescope to detect faint dwarf galaxies.
Physics and simulations have long predicted that the large-scale structure of the universe looks like it was spun by some colossal spider. Dark matter seems to have been distributed into filaments spanning lightyears, and that attracted regular matter like dust and gas to gather along those threads, too.
Galaxies and clusters tend to clump in the nodes where these filaments meet.
Hints of these cosmic webs have been indirectly observed before, through gravitational lensing or thanks to the bright light from
quasars illuminating the gas. But now, astronomers have managed to detect light from the hydrogen gas itself.
newatlas.com