In discussions about galaxies, two commonly referenced galaxies are the Milky Way and the Andromeda Galaxy.
The Milky Way and the Andromeda Galaxy are both part of the Local Group of galaxies and are on a collision course with each other. They are expected to collide in about 4 to 5 billion years. This interaction will likely initiate a complex gravitational dance between the two galaxies, leading to the merging of their stars and other matter over time. The process will significantly reshape both galaxies, creating a new galaxy often referred to as "Milkomeda" or "Milkdromeda". This collision will also influence the star formation rates in both galaxies as gas and dust are funneled into areas of higher density, potentially leading to bursts of new star formation.
These types of galaxy interactions can also trigger the formation of new structures, such as tidal tails and satellite galaxies, and can dramatically change the dynamics and morphology of both galaxies involved.