intergalactic hydrogen gas

What did the universe look like 11 billion years ago? Something like this: This image is part of the largest-ever 3-D map of the distant universe, which was released yesterday by scientists from the Sloan Digital Sky Survey III (SDSS-III) at the April meeting of the American Physical Society. Just a slice of the entire map, the image shows the distribution of intergalactic hydrogen gas: red areas have more gas, blue areas have less. Scientists usually map the universe by looking at galaxies. But this study, which was led by Brookhaven cosmologist Anže Slosar, observed how light from…