The observations of the cosmic web bolster the so-called cold dark matter theory of galaxy formation. “These observations of the faintest, largest structures in the universe are a key to understanding how our universe evolved through time, how galaxies grow and mature, and how the changing environments around galaxies created what we see around us,” said Erika Hamden, an astrophysicist at the University of Arizona. The team were able to detect individual filaments of intergalactic gas spanning young galaxies in a newly forming cluster. The latest observations used the European Southern Observatory’s Very Large Telescope to map out the light emitted by hydrogen irradiated by the galaxies within a distant galactic cluster called SSA22. These calculations predict that 60% of the hydrogen created during the big bang is distributed as long filaments strung out across space in the cosmic web. However, despite the colossal amounts of gas and dark matter they contain, theoretical predictions suggest that most of the gas in the universe resides in the spaces in between clusters. Galaxy clusters are the most tightly gravitationally-bound structures in the universe and can contain hundreds or thousands of galaxies. The cosmic web: a map showing the gas filaments and optical light coming from the galaxies.
