The good news is an asteroid that size would have burned up in the Earth's atmosphere. The bad news is there are still plenty of larger near-Earth rocks we haven't discovered yet -- and we may not discover them until they come flying at us.
Asteroid 2012 BX34, after all, had plenty of company. It was the 873rd space rock detected by NASA in the last two weeks. Only in the last couple of days did we discover that its orbit would bring it within one-fifth of the distance between here and the moon -- which is just what happened at 10 a.m. EST Friday. In cosmic terms, that's a hair's breadth. (Check it out in the video below.)
Had 2012 BX 34 been larger -- the size of a mountain, say -- gravity may well have put it on a collision course with our planet. At that scale, given mere days to prepare, we may have been looking at a Deep Impact-style scenario. We can only hope that the next civilization-ending rock we detect isn't quite so keen to meet us.
Suddenly, President Obama's priority for NASA in the next 10 years -- to land astronauts on an asteroid -- makes a lot more sense. Not only are there trillions of dollars in mineral wealth in those rocks, but the more we get to know them, the better we can detect and deflect their orbits.
[via Space.com]
Bonus: 23 Must-Follow Twitter Accounts for Astronomy Lovers
[nggallery id=1813]