2012 JU
© JPLOrbit diagram for asteroid 2012 JU.
OK, we admit that's a bit of an exaggeration, but an asteroid about the size of a school bus did come fairly close to Earth yesterday! On May 13, Asteroid 2012 JU passed harmlessly between Earth and Moon. This space rock is somewhere between 8 and 17 meters across, and it came within about 190,000 kilometers (118,000 miles) from Earth - about a half a Lunar Distance (LD), or 0.0014 AU. Its looping orbit is currently closely aligned with Earth's (click here to see JPL's orbit diagram applet) and will be moving rather slowly away from us over the next few weeks.

There are two other known space rocks that will be making somewhat close passes by Earth later this month: 2010 KK37, which might be about 43 meters wide, will come within 2.3 LD (880,000 km) on May 19, and 2001 CQ36, which might be as big as 170 meters wide, will go by at 10 LD (3.8 million km) on May 30. There is no threat of any of these asteroids hitting our planet.

Asteroids passing between the Earth and Moon happens on a fairly regular basis. Last month, on April 1, a 46-meter wide asteroid named 2012 EG5 came within 230,000 km, and on March 26 of this year, two smaller asteroids shaved by at a mere 58,000 km and 154,000 km. And in January 2012 BX34 passed by at just 59,600 km from the Earth's surface.