Astronomers have identified the closest known flyby of a star to our solar system: A dim star that passed through the Oort Cloud 70,000 years ago. A group of astronomers from the US, Europe, Chile and South Africa have determined that 70,000 years ago a dim star is likely to have passed through the solar system's distant cloud of comets, the Oort Cloud (image above). No other star is known to have ever approached our solar system this close - five times closer than the current closest star, Proxima Centauri.