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 ...

(via minutephysics) This video is about the interesting and often-misunderstood story of the asteroids, and how they lost their planet-hood status; more recently than you may think!

Planets are usually defined by the star they orbit. Take away the star, and a planet becomes almost impossible to find. This is because almost every method astronomers use to detect planets depends on ...