This computer simulation uses what we know about physical forces in the universe to model how a galaxy might have been born, and how it might grow over 13.5 billion years.
This cosmological simulation follows the development of a single disk galaxy over about 13.5 billion years, from shortly after the Big Bang to the present time. 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 in Moffett Field, Calif., and required about 1 million CPU hours. It assumes a universe dominated by dark energy and dark matter.
The result is a beautiful (if silent) video that is significantly labeled as public domain. It seemed like something you guys might enjoy playing around with.
Check out this Wikipedia article for more information on the growth of galaxies
Via labgrab