The universe's first helium, measured in 54 galaxies, matches the Big Bang story almost exactly

Astronomers with the Large Binocular Telescope's primordial helium project measured ancient gas in 54 metal-poor galaxies — places barely touched by later star-making. They found helium made up 24.58% of the early universe's matter by mass, strikingly close to the 24.67% predicted from measurements of the cosmic microwave background. Published in The Astrophysical Journal, the result strengthens one of the three pillars of the Big Bang model and clarifies how much helium stars themselves have added since.