Object Analysis

The Mice Galaxies (NGC 4676) are two spiral galaxies in the constellation Coma Berenices. About 290 million light-years away, they are in the process of colliding and merging. Their name refers to the long tails produced by tidal action—the relative difference between gravitational pull on the near and far parts of each galaxy.

These tails are distinct, long streams of stars and gas. The northern galaxy is seen nearly edge-on, while the southern galaxy is seen more face-on. The simulation of this collision suggests they have already passed through each other once and will eventually merge into a single elliptical galaxy.

The Mice are prototypical examples of a prograde collision, where the galaxies rotate in the same direction as their orbital motion around each other. This alignment maximizes the tidal forces, creating the spectacular tails we observe today.