SPACE - Early universe 'warmed up' later than previously believed, study finds

A new study from Tel Aviv University reveals that black holes, formed from the first stars in our universe, heated the gas throughout space later than previously thought. They also imprinted a clear signature in radio waves which astronomers can now search for. The work is a major new finding about the origins of the universe ...

http://phys.org/news/2014-02-early-universe-previously-believed.htm