Dark matter may have ripped up early universe

2019-03-08 11:01:01

By Marcus Chown BY ABOUT a billion years after the big bang, our universe was reionised. Hydrogen atoms were torn apart into electrons and protons, but the perpetrator has been something of a mystery. Could dark matter be responsible? Neutral atoms, mostly of hydrogen, formed about 380,000 years after the big bang, when the universe cooled enough for electrons and nuclei to combine. Most astronomers suspect that the hydrogen was reionised by the first generation of stars (see diagram). No telescope has ever peered far enough back in time to see the first stars form,