First Stars

The first few of the lightest elements were composed during the big bang, not with stars. At first, the universe was so hot that even the atoms were unstable, and as it chilled, hydrogen atoms formed first, with some helium and lithium and traces of beryllium. The contents of the stars and everything else occurred nothing but of these. All the other elements heavier than these were formed surrounding and inside the stars and dispersed into space in stellar explosions called supernovae. However, to this time we do not know exactly how the first stars began to shine. The first star lacked heavy elements; only hydrogen was present. So they couldn't collapse and cooled fast enough to start the fusion "engine". The collapse because of gravity provoked the hydrogen gas to become too hot and expand. The heavy elements radiate light, cooling it, so the formation of stars became easier after the first generation stars lived and scattered their substances into space with supernovae. But explaining the rapid formation of the first stars is still a challenge for theorists.