Helium clue found in echo of the big bang

 作者:罗夼剥     |      日期:2019-03-08 05:06:02
By Rachel Courtland THE subtle signal of ancient helium has shown up for the first time in light left over from the big bang. The discovery will help astronomers work out how much of the stuff was made during the big bang and how much was made later by stars. Helium is the second-most abundant element in the universe after hydrogen. The light emitted by old stars and clumps of hot pristine gas from the early universe suggest helium made up some 25 per cent of the ordinary matter created during the big bang. The new data provides another measure. …