In case you do not easily panic, you may have missed the story that two asteroids were passing close to Earth yesterday.  Not to worry, it happens all of the time, but because their existence was only discovered Sunday by the Catalina Sky Survey, people were concerned.

The 50-foot 2010 RX30 came within 154,000 miles of Earth, just over halfway from here to the moon (0.6 lunar distances if you want to impress your friends), yesterday morning and then 2010 RF12, about 30 feet in size, came within 50,000 miles of Earth yesterday afternoon.

Well, why mention it?   They got a lot of attention, that's why, so when science issues are unclear we jump onto the scene.   In reality, a small asteroid like that, and there are 50 million 'undiscovered' asteroids out there, probably travels between the Earth and the Moon every day, we just never notice it because our instruments looking for real danger filter out noise signals - rocks smaller than a hundred feet.


See?  It's already gone.   The red in the center is Earth.  Courtesy: NASA

Because they weren't endangering satellites and even if they 'hit' Earth they would simply disintegrate in the atmosphere, it was just a lucky fluke that Catalina took note of it.  Once every 10 years one of the asteroids that gets within a lunar distance of Earth might hit our atmosphere but surprises do happen

Don't believe me?  Convinced the Mayans are doing military probes in preparation for Dec. 21, 2012?  Look at the NASA close-approach data yourself.