View Full Version : M31

2010-Oct-06, 05:20 PM
Early on in astronomical history, galactic rotation curves were expected to be simple; they should operate much like the solar system in which inner objects orbit faster and outer objects slower. To the surprise of many astronomers, when rotation curves were eventually worked out, they appeared mostly flat. The conclusion was that the mass we [...]

More... (http://www.universetoday.com/75164/m31s-odd-rotation-curve/)