Yesterday, astronomers had the thrill of detecting an asteroid headed straight for earth and watching it hit our planet’s atmosphere just when they predicted, but without any of the panic that might be expected to accompany the foreknowledge of an asteroid strike. The space rock, which was about nine feet in diameter, was too small to do any damage, and burned up in the atmosphere while astronomers watched.
The object’s entry into the atmosphere wasn’t that unusual: Such an event happens roughly every three months. But this is “the first time we were able to discover and predict an impact before the event”, says Donald Yeomans, manager of NASA’s Near-Earth Object (NEO) programme [Nature News]. Researchers say the accurate prediction bodes well for humanity, for it suggests that astronomers are up to the challenge of detecting and tracking larger asteroids that could pose a more serious threat to human populations. Says Yeomans: “There are still a few kinks, a few processes that need to be smoother. But we passed this test” [Nature News].
The object was first spotted on Monday by the Mount Lemmon Observatory near Tucson, Arizona. Astronomers then calculated that the asteroid, called 2008 TC3, should hit Earth’s atmosphere above northern Sudan at 0246 on Tuesday 7 October…. It turned up right on time. NASA’s Near Earth Object Program now report that the fireball was seen at 0245 and 45 seconds [New Scientist].
No photographs of the explosion have been reported, owing to the remote location of the object’s path over Sudan. But the explosion was recorded by an infrasound array in Kenya. Peter Brown at the University of Western Ontario estimated, based on the infrasound data, that the asteroid exploded at 0243 UT with an energy of somewhere between 1.1 and 2.1 kilotons of TNT [SPACE.com]. Researchers say a few fragments of rock may have fallen to earth, but they’re not suggesting that adventurers go meteorite hunting; if pieces did reach the ground, they’d be scattered in an area near Sudan’s dangerous Darfur region.
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