The theory that the expansion of our Universe is accelerating got another boost this week by a group of researchers from Princeton University. They used data in the Sloan Digital Sky Survey to measure the light from 3,000 quasars. They weren’t looking at these quasars, though, but at diffuse hydrogen gas that sits in space partially obscuring the intervening space. The light from the quasars is changed depending on how much this gas that it has to go through. The astronomers were able to get a sense of how this gas clumped together over time, and their results exactly match the inflationary model of the Universe.