Black holes light up the Universe

2019-03-07 02:17:17

By Stephen Battersby HUNGRY black holes that lie billions of light years away produce as much as a third of all the radiation in the Universe, astrophysicists suggest. Andrew Fabian and Kazushi Iwasawa of the University of Cambridge say the radiation comes from quasars—gigantic black holes that grow by sucking in gas, which heats up and shines brilliantly. But they believe that many quasars are hidden behind clouds of dense, cold gas, which absorbs most of the radiation and only lets X-rays escape. This could explain a mysterious glow of background radiation in the Universe. Satellite observations have shown that space is bathed in a sea of X-rays. Fabian and Iwasawa have calculated that this could come from billions of distant, hidden quasars. “Quasars might be important sources of radiation in the Universe,