M31-Milky Way Collision

This computer simulation illustrates the projected collision of the Milky Way with the Andromeda Galaxy (M31). The two galaxies, the largest in the Local Group, are presently separated by about 780 kpc but are moving toward each other at 300 km/s. They will probably collide in about 2 billion years.

Notice that the two galaxies passes through each other and fling out great streamers of matter before colliding again and beginning to merge into a single galaxy. In such a collision between galaxies the individual stars are very unlikely to collide with each other directly. The interaction is mostly gravitational between the stars, but the compression of gas and dust as the galaxies pass through each other will likely trigger strong star formation. Usage: Click "Play" to begin and "Stop" to halt. "Step" moves forward one step and "Back" moves backwards one step. "Home" returns to the beginning from any point.