Asteroid 2012 LZ1

An asteroid 1,650 feet across came within 3.3 million miles of Earth yesterday.  That's not overly close, and NASA says it poses no threat to Earth for the foreseeable future, but in the context of the size of the Solar System, a few million miles is a relatively near miss.

Asteroid 2012 LZ1, as it is designated, may not represent any threat itself, but it is still worrisome.  A rock that size, if it hit Earth, could cause a major disaster, and it was only discovered this year.  Had we been in its path, that would've been far too late to attempt to deflect it away.  NASA says there are still many such objects yet to be found.