The Fate of the Sagittarius Dwarf Galaxy 

In 1994, astronomers in Cambridge University discovered a dwarf galaxy, located in the direction of the constelltaion of Sagittarius, whose morphology appeared to be severely distorted. This is a picture (created with the help of Chris Mihos) of how this distortion might have occured. The dwarf galaxy, initially a ball of stars (at the top of the picture), falls towards the Milky Way along the dashed line and is torn apart by immense tidal forces. The stars ripped from the dwarf spread out in long streamers along its path. Click here for links to an animation of a similar simulation. 
Kathryn V. Johnston