Movie: N-body simulation of “The Mice”, by John Dubinski.
The Collision and Merger of Spiral Galaxies Spiral galaxies form in the early universe from the gravitational collapse of clumps of dark matter and gas which grow out of primordial density fluctuations. Sometimes spirals form in bound pairs, or groups or even clusters and so even though they may have time to develop into a independent disks with spiral structure, they are destined to fall together and collide. The results are spectacular as gravity pulls out long tidal tails of stars during the first pass and leads to the ineluctable merger of the spirals into a single elliptical galaxy. The merging process occurs very frequently in the early universe but less so today. Even so there are many nearby examples of merging galaxies. Our own galaxy, the Milky Way, will most likely merge with its nearest neighbour Andromeda in 3 billion years.
This is a movie of the simulation of “The Mice” – a well-known interacting pair of galaxies. This simulation was done for National Geographic magazine and appeared in the Feb. 2003 issue.
Credit: John Dubinski, CITA, Toronto
Original video from: http://www.cita.utoronto.ca/~dubinski/nbody/Mice_long.mpg (File size is about 22 MB).