October 31, 2011
‘Continent Killer’ Asteroid On Possible Collision Course With Earth
On the heels of the return to Earth of a pair of satellites -- NASA's Upper Atmosphere Research Satellite (UARS) and the German-built RÃ¶ntgensatellit (ROSAT) -- over the past two months comes a report of another object set to collide with our planet.
Only this one is a 20 million ton asteroid that is currently heading towards us at 23,000 miles per hour, and could collide with our planet in approximately 25 years, Alex Hannaford of the Telegraph wrote on Sunday. The asteroid in question, Apophis, is more than 800 feet wide, comprised of a mixture of rock, ice, and dust, and has been dubbed "the continent killer.""There are two scenarios," Hannaford writes. "The first, and thankfully most likely, is that Apophis will fly by in April 2029, the year it is due to make its first 'close approach', and that´s the last we´ll see or hear of it. The second is that during that approach, it´ll pass through what scientists refer to as a 'keyhole' -- a small area of space that can alter the asteroid´s course due to Earth´s gravity."
"If this happens, it´ll be on a massive collision course with us seven years later, likely to be April 13, 2036 -- Easter Sunday," the Telegraph reported added, noting that experts with NASA's Jet Propulsion Laboratory in California claim that it is "too far away" to predict which of the two possibilities is most likely, but that they should be able to know more in the near future.
"We don´t know precisely where Apophis is headed but we will soon, when it becomes observable again, probably in 2012 or 2013," Paul Chodas of the U.S. space agency's Near Earth Object (NEO) said. "Once we get radar on it we will be able to nail down its orbit and we will know the chances of it going through the keyhole and hitting in 2036. By that time, it could be a four in a million chance, and that could very well go down to zero."
That might not be the end of it, though, as Chodas told Hannaford that the asteroid could find another one of those "keyholes" -- small regions of space that can alter the course of a passing asteroid, due to a planet's gravity -- meaning that even if it misses the planet the first time, it could theoretically return and collide with the Earth's surface later on.
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