Two small asteroids buzzed by Earth, zooming well within the moon’s orbit, over the last 48 hours. Neither posed any danger, but the events were eagerlycaptured by amateur astronomers, and the second encounter was a record-setter.
The second asteroid, named 2012 KT42, zipped by at midnight PDT on May 29, coming within 8,950 miles of Earth. That's closer than the orbit of geosynchronous satellites, making the KT42 encounter one of the top 20 closest approaches ever recorded. The asteroid was discovered only a day before its flyby, but is a puny 15 feet across, not much bigger than a minivan.
To get a sense of how close each asteroid came, the moon orbits at a distance of 240,000 miles from Earth. Most near-Earth objects pass much farther away than lunar orbit.
Both NASA and amateur astronomers scan the skies for potentially dangerous asteroids. These two were detected so late because their small size made them hard to see. Officials with the Asteroid Watch program at NASA's Jet Propulsion Laboratory tweeted the passage of each rock, noting that each was at an intimate but safe distance.
Even if one had hit Earth, the damage would be modest. In the case of KT42, the rock “would likely disintegrate almost entirely in the atmosphere, peppering the ground below with relatively small meteorites,” wrote astronomer Tony Philips on Spaceweather.com.
Images: 1) Record-setting asteroid 2012 KT42 streaking by, six minutes before its closest approach to the Earth. Alex R. Gibbs, Catalina Sky Survey, University of Arizona, NASA Near-Earth Object Program. 2) Telescope images of asteroid 2012 KP24, which came within 32,000 miles of Earth on May 28. Richard Kowalski, Catalina Sky Survey, University of Arizona, NASA Near-Earth Object Program.*