A computer simulation offers a detailed picture of how the first stars in the universe came into existence soon after the Big Bang. Researchers at Nagoya University, National Astronomical Observatory of Japan, and Harvard University in the U.S. used a sophisticated computer simulation to study how cosmic primordial gases would have evolved under the action of gravity to form a protostar -- the early stage of a massive star. This new simulation shows that the protostar was very small when it was born, with its mass being just one percent of the sun. According to the researchers' further study, however, the protostar would likely evolve into a massive star capable of synthesizing heavy elements soon after the Big Bang. These first primordial stars are also thought to be the first objects that lit up the universe.