Intergalactic Hydrogen Bridges Could Be Source for Star Formation

Long after a galaxy's peaked in star production


New observations of a bridge of tenuous hydrogen gas stretching between two nearby galaxies may help solve a longstanding puzzle: Billions of years after star formation peaked in the universe, what continues to fuel the formation of new stars in spiral galaxies like the Milky Way?

Newly published radiotelescope observations of this segment of what researchers have dubbed the "cosmic web" reveal that about half of the neutral hydrogen gas in the bridge is contained in rotating clumps the size of dwarf galaxies. Neutral hydrogen – atoms with one proton and one electron – represents the raw material for new stars.