Astronomers have known that roughly 12 billion years ago, the gas in deep space was much more opaque than it is now in some regions, although the opacity varied widely from place to place. But they weren’t sure about what caused those variations. To learn why the differences occurred, University of California, Riverside astronomer George Becker and co-authors used the Subaru Telescope on the summit of Mauna Kea in Hawaii to search for galaxies of...
