The Milky Way meets a sausage

Eight to ten billion years ago, thus, in its youth, our Milky Way apparently had a fateful encounter: it crossed paths with another, significantly smaller galaxy. The researchers who discovered this gave the smaller galaxy the name “Sausage Galaxy,” but this is perhaps a little unfair, because in reality it had a similar elliptical shape as the Milky Way.
The name “Sausage” came from the way the collision was proven. To do this, astronomers examined the distribution of velocities of the stars...