One million alien visitors from another star system could already be lurking in the solar system. We aren't talking about "little green men" here, however — more "little (and not so little) gray rocks ...

Just 4.3 light years from Earth lies a star called Alpha Centauri A, which is famous for being the nearest star that resembles our own Sun. In the popular Avatar movies, this star's system is home to ...

WASHINGTON (Reuters) - Astronomers have identified a quartet of small rocky planets orbiting Barnard's star - one of our closest stellar neighbors - though they concluded that all of them are too hot ...