The Milky Way has collided with and absorbed smaller galaxies throughout its history, which is a typical process in the evolution of large galaxies. These minor galactic mergers involve dwarf galaxies, and our Milky Way has had multiple such events.

One of the most significant of these occurred about 8-11 billion years ago when the Milky Way collided with a galaxy known as Gaia-Enceladus or the “Gaia Sausage” galaxy, named for its sausage-shaped distribution of stars. This event was a major one in the history of the Milky Way and helped shape its thick disk and stellar halo.

Another significant event is the ongoing collision with the Sagittarius Dwarf Elliptical Galaxy. This galaxy is currently in the process of being absorbed by the Milky Way and has likely orbited and passed through the Milky Way’s disk multiple times in the past.

In addition to these, there are likely many other minor mergers that have contributed to the Milky Way’s growth and evolution over its approximately 13.6 billion year history.

Looking to the future, the Milky Way is predicted to collide with the Large Magellanic Cloud in about 2.4 billion years. This event is expected to significantly affect the Milky Way’s structure. The most substantial anticipated collision is with the Andromeda galaxy, as mentioned before, which is expected to happen in about 4.5 billion years.