A small asteroid that zipped by the Earth this week has turned out to be no slow poke. It is the second-fastest spinning asteroid ever seen, astronomers say.
The space rock, called asteroid 2010 WA, flew within 24,000 miles (38,000 kilometers) of Earth Tuesday night (Nov. 16). [Photo of asteroid 2010 WA]
The asteroid was tiny, just 10 feet (3 meters) across and posed no threat of hitting Earth. In fact, it was so small that it would break apart before passing through Earth's atmosphere, NASA scientists said.
"We measured the rotation rate of the asteroid at about 31 seconds," astronomer Eileen Ryan, the observatory's director, told SPACE.com in an e-mail. "This makes it the second fastest rotating asteroid discovered to date."
The fastest spinning asteroid currently known is an asteroid called 2010 JL88, which spins once every 24.5 seconds and was also discovered using Magdalena Ridge Observatory's telescope, Ryan said.
Despite its small size, the asteroid still appeared as a bright object on a dark background in images taken by the observatory's telescope, which is built for tracking near-Earth objects (NEOs) and satellites, Ryan said.
"Because of this unusual feature, tracking fast-moving NEOs like 2010 WA is fairly easy for us," Ryan said.
The next time asteroid 2010 WA will come anywhere near Earth's cosmic neighborhood is in September 2013, but that pass will be considerably farther - about the equivalent of the distance between the Earth and the sun (93 million miles, or 150 million km), Ryan added.
On Oct. 12, the asteroid 2010 TD54 passed Earth at nearly the same miss distance as 2010 WA. A month earlier astronomers caught a rare sighting of two asteroids — known as 2010 RX30 and 2010 RF12 — when they both passed within the moon's orbit on the same day (Sept. 8).
