HONOLULU – A trio of bubble-blowing galaxies may offer clues about one of the greatest cosmic makeovers in the history of the universe.
Sometime during the universe’s first billion or so years, most of the hydrogen atoms in the cosmos became ionized when their electrons were torn away (SN: 11/7/19). Astronomers suspect that this reionization — so called because all hydrogen had been previously ionized for the first few hundred thousand years — was triggered by harsh ultraviolet light from the first generations of stars.
Now, researchers say they’ve caught a few galaxies blasting out ionizing light and stripping electrons from surrounding hydrogen just 680 million years after the Big Bang. If so, this would be the first direct evidence of a group of galaxies working together to ionize the early cosmos.
James Rhoads, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Md., presented the results January 5 during a news conference at a meeting of the American Astronomical Society.