Galaxy interactions occur when two or more galaxies come close enough to affect each other's gravitational fields. This can lead to various phenomena, such as tidal forces that distort their shapes, star formation triggered by gas compression, and even the merging of galaxies over time. These interactions can result in different types of galaxies, such as elliptical galaxies formed from the merger of spiral galaxies. The Milky Way is currently on a collision course with the Andromeda Galaxy, which will significantly alter both galaxies in the distant future.