Should Apophis strike the Earth it would live up to its name, releasing 100,000 times the energy of the Hiroshima blast and throwing up enough debris to plunge the world into darkness. Such strikes are believed to have caused mass extinctions in the Earth's past and have the potential to wipe out the human race.

In an effort to avoid Armageddon, the Planetary Society has announced a $US50,000 prize for whoever can tag the comet in time to predict its exact path during the 2029 flyby. If Apophis passes through a window of several hundred metres during this flyby, it will impact Earth on its return in 2036. The competition requires the tagging mission to return data by 2017, in time for scientists to determine whether they need to send a mission to deflect the asteroid from the window when it passes the Earth in 2029. The deadline for proposals is August 31, 2007.

While the chances of Apophis striking the Earth in 30 years are "very slim," such Near-Earth Objects represent a real threat and the competition is designed to address the issue before it's too late, said Bruce Betts, the Planetary Society's Director of Projects.

"With this competition, we hope not only to generate creative thinking about tagging Apophis, but also to stimulate greater awareness of the broader near-Earth object threat," he said

"Learning how to do this is the point of the competition."{moscomment}