Some 70,000 years ago, when humans and Neanderthals shared the planet, an alien star streaked through the outer edges of our solar system and jostled its contents, astronomers say. In a study of hundreds of solar system objects with unusual orbits, the scientists also noted eight comets that may have interstellar origins.
This idea that a star recently sideswiped our solar system was first raised three years ago by University of Rochester astronomer Eric Mamajek. He and his colleagues had noticed something strange while studying a binary stellar system named Scholz's star, which comprises two small, dim stars orbiting each other. Even though Scholz's star is just 20 light-years from Earth — a near neighbor, by astronomical standards — it appeared to move incredibly slowly across the night sky. The best explanation was that Scholz's star was cruising away from us. Which means at some point, it must have been quite close by.
It most likely wasn't the first time. ;-) To read more, click here.