Galaxies without stars: The problem of the missing hydrogen in the early Universe
Friday, November 9, 2012 - 09:02
in Astronomy & Space
(Phys.org)—Hydrogen is the most common element in the Universe, making up 75% of all normal matter and the content of stars. Although stars themselves are hot, they can only form out of the coldest gas when a massive cloud of hydrogen can collapse under its own gravity until nuclear fusion starts – the fusing of atoms together which releases the huge amounts of energy we see as starlight.