Galaxy merger

The Mice Galaxies (NGC 4676 A&B) are in the process of merging.
This artist's impression shows the merger between two galaxies leading to the formation of a disc galaxy.

Galaxy mergers can occur when two (or more) galaxies collide. They are the most violent type of galaxy interaction. The gravitational interactions between galaxies and the friction between the gas and dust have major effects on the galaxies involved, but the exact effects of such mergers depend on a wide variety of parameters such as collision angles, speeds, and relative size/composition, and are currently an extremely active area of research. Galaxy mergers are important because the merger rate is a fundamental measurement of galaxy evolution and also provides astronomers with clues about how galaxies grew into their current forms over long stretches of time.[1]

  1. ^ "Astronomers Pin Down Galaxy Collision Rate". HubbleSite. 27 October 2011. Archived from the original on 8 June 2021. Retrieved 16 April 2012.