'Doomsday asteroid' poses no threat
2013-01-11 22:01
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NASA
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Washington - A space rock popularly dubbed the
"doomsday asteroid" because of fears it could smash into Earth a
couple of decades from now poses no risk, National Aeronautics and Space
Administration (Nasa) said after new observations of the object.
Asteroid 99942 Apophis was scanned by optical telescopes
and deep-space radars as it made a flyby this week, the Nasa said in a press
release.
Named after the god of evil and darkness in Egyptian
mythology, Apophis sparked a scare when it was first detected in 2004.
Early calculations suggested a 2.7% probability of
collision in 2029, the highest ever for a detected asteroid, but this risk was
soon discarded after further observations.
A question mark, though, remained over an impact for 13 April
2036, which Nasa initially put at one in 45 000 and then lowered to one in 250 000.
The new observations show that even this remote
probability can be excluded, Nasa’s Jet Propulsion Laboratory (JPL) said in the
statement on Thursday.
"With the new data... we have effectively ruled out
the possibility of an Earth impact by Apophis in 2036," said Don Yeomans,
in charge of the JPL's Near-Earth Object Programme.
"The impact odds as they stand now are less than one
in a million, which makes us comfortable saying we can effectively rule out an
Earth impact in 2036. Our interest in asteroid Apophis will essentially be for
its scientific interest for the foreseeable future."
The 2036 flyby will be the closest of an asteroid of this
size, for Apophis will come within 31 300km, meaning that it will zip
within the ring of geostationary orbits.
On 15 February, asteroid 2012 DA14 will come even closer.
Yeomans said DA14 was 40m across and would skim the
planet at just 27 500km.
Images of Apophis captured this week by the European
Space Agency's Herschel telescope found it measured around 325m across, about a
fifth bigger than previously thought.