For the first time ever, astronomers have spotted an alien space rock floating around in our solar system. The asteroid is the first unexpected visitor from outside our system, and it’s moving fast (5.8 miles per second) so scientists are frantically trying to learn as much as possible about it before it disappears. Discovered by Hawaii’s Pan-STARRS 1 telescope, the rock is less than a quarter mile in diameter but fascinating regardless. Paul Chodas—the manager of NASA’s Center for Near-Earth Object Studies—says “We’ve been expecting this for decades, really. We don’t know enough about how much material is floating around between the stars. And so this will give us the first data point. We hope to find more of this stuff.” Read more at NPR.