Alien star system buzzed the Sun
An alien star passed through our Solar System just 70,000 years ago, astronomers have discovered.
No other star is known to have approached this close to us.
An international team of researchers says it came five times closer than our current nearest neighbour - Proxima Centauri.
The object, a red dwarf known as Scholz's star, cruised through the outer reaches of the Solar System - a region known as the Oort Cloud.
More: http://www.bbc.co.uk/news/science-environment-31519875
FAQ about Scholz's star (WISE J072003.20-084651.2), which had the closest known flyby of a star system to the solar system
Lots of detail: http://www.pas.rochester.edu/~emamajek/flyby.html