Russian scientists have released a report that warns of an asteroid more than 200 yards across could collide with the Earth on April 13, 2036. The asteroid, known as Apophis, was mentioned by NASA scientists in 2004, who said the asteroid would impact our planet in 2029, a warning which has since been rescinded.
The Russian scientists are basing their prediction, reportedly, on the odds that the huge asteroid will travel through what's known as a gravitational keyhole as it passes close to our planet in 2029. The gravitational keyhole is a particular area in space, slightly larger than the asteroid itself, which could alter the asteroid's path.
“The situation is that in 2029, April 13, [Apophis] flies very close to the Earth, within five Earth radii, so that will be quite an event, but we’ve already ruled out the possibility of it hitting at that time,” a NASA scientist said in response to the Russian report. “On the other hand, if it goes through what we call a keyhole during that close Earth approach … then it will indeed be perturbed just right so that it will come back and smack Earth on April 13, 2036,” the scientist added. He said that the chances of Apophis traveling through the keyhole are minimal.
The more likely scenario is that Apophis will be observed extensively in late 2012 and 2013 as it comes fairly close to the Earth, and NASA will be able to design a scheme and necessary machinery to alter its orbit if it appears to be on a long-term collision course with the Earth, which would reduce the doomsday scenario probability to zero.