Tycho's Supernova

blamanj writes "Over 400 years ago, a supernova was visible in Nothern Europe. Astronomer Tycho Brahe helped bring about the collapse of the Ptolemaic system by showing that the 'new star' was not a local phenomena like a comet, but actually existed in (supposedly) unchanging heavens. The star that went nova was part of a binary system, and the supernova explosion sent the companion star shooting off into space. Now, that companion star has been found."