Asteroid to pass Earth harmlessly Wednesday

A small (10 meter wide) asteroid will pass by the Earth Wednesday, at 12:47 UT. This tiny rock, called 2010 AL30, will pass us at a safe distance of 130,000 km (80,000 miles). As cosmic encounters go, this is a hair's breadth, but in human terms it's a long way off; as this graphic makes clear. It's about a third of the way to the Moon. 2010 AL30 was only discovered on Monday. It's escaped our previous notice because it's dinky. Even when it passes you'll need a telescope to see it. There has been some speculation that this was a man-made object like a rocket booster, since it's about the right size, and sometimes near-Earth objects turn out to be space junk. But in this case the orbit doesn't really match any rocket trajectory, so it's probably a natural rock. And since I know someone would ask, if this ...