February 4, 2013
Small Asteroid Will Pass By Earth Safely
NASA's Jet Propulsion Laboratory
The small near-Earth asteroid 2012 DA14 will pass very close to Earth on February 15, so close that it will pass inside the ring of geosynchronous weather and communications satellites. NASA's Near-Earth Object Program Office can accurately predict the asteroid's path with the observations obtained, and it is therefore known that there is no chance that the asteroid might be on a collision course with Earth. Nevertheless, the flyby will provide a unique opportunity for researchers to study a near-Earth object up close.
Asteroid 2012 DA14 will be closest to Earth on Feb. 15, at about 11:24 p.m. PST (2 p.m. EST and 1924 UT), when it will be at a distance of about 27,700 kilometers (17,200 miles) above Earth's surface. Although this is close enough for the asteroid to pass inside the ring of geosynchronous satellites, located about 35,800 kilometers (22,200 miles) above the equator, it will still be well above the vast majority of satellites, including the International Space Station. At its closest, the asteroid will be only about 1/13th of the distance to the moon. The asteroid will fly by our planet quite rapidly, at a speed of about 17,400 mph (7.8 kilometers per second) in a south-to-north direction with respect to Earth.
2012 DA14 has not been in the catalogues for very long -- it was discovered in February of 2012 by astronomers at the La Sagra Sky Survey program in southern Spain and reported to the Minor Planet Center, which designates minor bodies in our solar system. At the time of the discovery, the asteroid had just made a fairly distant passage by Earth, about seven times farther than the distance to the moon. Since 2012 DA14's orbital period around the sun has been about 368 days, which is very similar to Earth's, the asteroid made a series of annual close approaches. This year's is the closest approach, and is the closest the asteroid will come for at least three decades. But this encounter will shorten 2012 DA14's orbital period to about 317 days, changing its orbital class from Apollo to Aten, and its future close approaches will follow a different pattern.
This passage of 2012 DA14 by Earth is a record close approach for a known object of this size. A few other known asteroids have flown by Earth even closer, but those asteroids were smaller. On average, we expect an object of this size to get this close to Earth about once every 40 years. An actual Earth collision by an object of this size would be expected much less frequently, about once every 1,200 years, on average.
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