The Mixture of Elements

During the Big Bang, only the lightest elements were formed – hydrogen, helium and small amounts of lithium and beryllium. As the clouds of cosmic dust and gases from the Big Bang cooled, stars formed and there then grouped together to form galaxies. The Big Bang theory explains how much of each element should have been created in the early universe, and what we see in very distant galaxies and old stars supports this idea.

It is not possible to look in new stars, such as our Sun, for this evidence since they contain elements that have been formed in previous generations of stars. This is as the composition of new stars will be very different from the composition of stars that formed around 7 billion years ago, closer to the Big Bang.