A good-sized asteroid sailing past our planet right now turns out to be two giant rocks doing a celestial jig.
The setup, catalogued as 2008 BT18, was thought to be nearly a half-mile wide after its discovery by MIT's LINEAR search program in January. Nothing else was known about it.
More: http://www.livescience.com/space/080713-binary-asteroid-2008-BT18.html