The Mice Galaxies are two spiral galaxies in the constellation Coma Berenices. About 290 million light-years away, they began the process of colliding and merging about 290 million years ago.
In one galaxy a 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.