Space‐Based Telescopes See Primordial Helium in Spectra of Distant Quasars

According to the standard model, shortly after the Big Bang, primordial hydrogen and helium were spread nearly uniformly throughout space. After matter began to coalesce into galaxies and other structures, nuclear cooking within massive stars produced heavier elements. But researchers still expect to see traces of the primordial elements if they look far out in intergalactic space, at distances corresponding to the earliest times. In 1971 they saw signs of hydrogen clumped in clouds located billions of light‐years away. Now, thanks to the availability of satelliteborne telescopes sensitive to ultravio let radiation, they have found hydrogen's primordial companion.