Astronomers know that mergers play a huge role in galaxy growth. Right now, the Milky Way is slowly consuming the Large and Small Magellanic Clouds. The evidence is a stream of gas called the Magellanic Stream that's about 600,000 light-years long. The Milky Way (MW) is stripping this gas from the clouds, which don't have enough mass to retain it. They're losing the gravitational tug-of-war with the much more massive MW.