Located 300 million light-years away in the constellation Coma Berenices, these two colliding galaxies were captured by the Advanced Camera for Surveys (ACS), onboard the NASA/ESA Hubble Space Telescope in 2002.
The galaxies have been nicknamed “The Mice” because of the long tails of stars and gas emanating from each galaxy. Otherwise known as NGC 4676, the pair will eventually merge into a single giant spherical galaxy (known as an elliptical galaxy). The stars, gas, and luminous clumps of stars in the tidal tails will either fall back into the merged galaxies or orbit in the halo of the newly formed elliptical galaxy.
The image shows the most detail and the most stars that have ever been seen in these galaxies. In the galaxy at left, the bright blue patch is resolved into a vigorous cascade of clusters and associations of young, hot blue stars, whose formation has been triggered by the tidal forces of the gravitational interaction. Streams of material can also be seen flowing between the two galaxies.
The process of colliding and merging began about 290 million years ago.