
Most helium in the Universe is primordial helium, formed during the Big Bang. But a fraction of helium was formed by long-dead stars. Distinguishing between the two allows astronomers to further confirm our observations of the Big Bang.

Most helium in the Universe is primordial helium, formed during the Big Bang. But a fraction of helium was formed by long-dead stars. Distinguishing between the two allows astronomers to further confirm our observations of the Big Bang.