ONLY about half the hydrogen gas in the early Universe ended up in galaxies
like our own—the rest went missing. Now astronomers claim they’ve found
it. “A substantial amount of it appears to be in superhot clouds hiding in
intergalactic space,” says Todd Tripp of Princeton University in New Jersey.
Astronomers suspected that a huge amount of hydrogen had gone missing because
deuterium—heavy hydrogen—was once abundant in interstellar space.
The deuterium is thought to have been forged in the first few minutes after the
big bang, but it is easily converted into helium if there is a…
