  The nature of the first generation of stars in the Universe remains largely
unknown. Observations imply the existence of massive primordial stars early in
the history of the universe, and the standard theory for the growth of cosmic
structure predicts that structures grow hierarchically through gravitational
instability. We have developed an ab initio computer simulation of the
formation of primordial stars that follows the relevant atomic and molecular
processes in a primordial gas in an expanding universe. The results show that
primeval density fluctuations left over from the Big Bang can drive the
formation of a tiny protostar with a mass of just one percent that of the Sun.
The protostar is a seed for the subsequent formation of a massive primordial
star.
