miles of Earth — about 60 percent of the Earth-moon distance — at 5:51 a.m. EDT. This asteroid is estimated to be about 42 feet across.

The second, 2010 RF12, will come almost 12 hours later, at 5:12 p.m. EDT. It will swing by Earth at just 20 percent the Earth-moon distance, or 47,845 miles. 2010 RF12 is even smaller, only about 23 feet across.

Both were just discovered on September 5 by astronomer Andrea Boattini, working with a 1.5-meter reflecting telescope at Mount Lemmon in Arizona as part of the Catalina Sky Survey’s routine scanning of the skies.

According to NASA’s Near Earth Object impact risk tables, the odds that 2010 RF12 will hit the Earth are about 1 in 50, and the odds of an impact with 2010 RX30 are less than 1 in 1000. Both objects are too small to do much damage even if they were to smack into the Earth; much of their rocky mass probably wouldn’t survive the trip through Earth’s atmosphere. Because of their small sizes, they won’t be visible with the naked eye. But they should be bright enough to observe with a modest-sized telescope, according to NASA’s Near Earth Object Program.

The two asteroids are on unrelated orbits. The fact that they’re scheduled to arrive so close to each other is purely a cosmic coincidence.

Via SpaceWeather.com

Images: 1) Asteroid Ida as imaged by the Galileo spacecraft in 1993. Credit: NASA 2) Orbits of 2010 RF12 and 2010 RX30 from JPL’s Small Body Database Browser

See Also:

• Wednesday’s Near-Earth Asteroid Caught on Film
• Earth to Get Close Shave Wednesday From Newly Discovered Asteroid …
• How to Defend Earth Against an Asteroid Strike
• Video: The Asteroid That Will Almost Hit Earth
• The Real Twitpocalypse: Asteroid Alerts Come to Twitter

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Authors: Lisa Grossman

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