Our galaxy is on a collision course with another one!
Don't worry though, it's not going to happen for another 4 billion years. Scientists have finally managed to predict what's going to happen between the Milky Way and Andromeda: They're going to collide head on in about 4 billion years.
Thankfully, if humans are still living on Earth by then, they're in no danger. Because stars in both galaxies are so far apart, the chances of any stars colliding are slim to none. What's most likely to happen is that the new combined galaxy will have a new gravitational center and reshape itself into a new elliptical galaxy. Our solar system will simply be thrown into another orbit.