GIANT stars did indeed illuminate the early universe. Astronomers have wondered whether the first coalescing gas clouds would have been unstable and fragmented to create only small primordial stars. Now the most complete simulation yet of star formation after the big bang suggests this did not happen.
In the model, created by a team led by Naoki Yoshida of Nagoya University in Japan, huge stars coalesce about 300 million years after the big bang. At first, patches of hydrogen and helium gas collapse under gravity and slowly warm up. Hydrogen atoms then form molecules, which radiate away the building heat,…
