Computer Model Shows a Disk Galaxy's Life History

This cosmological simulation follows the development of a single disk galaxy over about 13.5 billion years - from shortly after the Big Bang to now. Colors indicate old stars (red), young stars (white and bright blue), and the distribution of gas density (pale blue); the view is 300,000 light-years across. The simulation ran on the Pleiades supercomputer at NASA's Ames Research Center, and required about one million CPU hours.