Friday, 19 April 2013

NASA: Asteroid Apophis Not Threat to Earth At Least for Century

Radar views of asteroid Apophis
A series of radar maps acquired in January 2013 barely resolve 99942 Apophis, a threatening near-Earth asteroid. These views, acquired with NASA's big radio dish Goldstone, California, have a horizontal resolution of about 250 feet (75 m).

A Tumbling Apophis: Good News for Earth


Posted by Kelly Beatty, April 19, 2013

Asteroid 99942 Apophis isn't a huge threat to Earth — at least not for the next century. Telescopic observations made in early 2013 show that it is both elongated and tumbling, characteristics that help predict its future location.

Asteroid 99942 Apophis has been worrisome ever since its discovery in 2004. Estimated to be a bit more than 1,000 feet (300 m) across, it would deliver the kinetic-energy equivalent of 500 megatons of TNT were it to strike Earth — which it might well do some day. At first, dynamicists predicted a dangerously close pass in 2029 and a 3% chance of collision. More observations eased those fears — but triggered worry instead about a threatening flyby in March 2036.

As I reported three months ago, radar observations made last January have seemingly ruled out any chance of an impact in 2036. Barely resolved views made with NASA's big radar dish at Goldstone, California, even show Apophis to be quite elongated (as many near-Earth asteroids are).

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Source: Sky and Telescope Magazine.


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