Science Magazine: Immediately after the Big Bang, the universe was uniform, homogeneous, and completely free of stars. The gravitational collapse of dark matter gathered gas with it that cooled, collapsed further, and formed stars. Observations over the past 20 years have revealed the dynamic star-formation history of the universe. The star-formation rate peaked 10 billion years ago, when stars formed an order of magnitude faster than in the modern universe. Deep observations have begun to reveal the early history of star formation, but how quickly star formation started remains controversial, with results from observations of early galaxies suggesting a slower start than distributions of distant gamma-ray bursts that trace young stars. However, simulations using standard prescriptions for energetic feedback from star formation (from stellar explosions and ionizing radiation) have tended to predict a substantially earlier peak than either of these methods shows.
Comments
Post a Comment