He is forgotten sometimes, but the enemies of environment of the Earth are sometimes elsewhere. If that's how it is big asteroids likely to scratch from the card an end of our planet. Evénements extremely rare, very happily, seen spectacular damage that they can cause, as, very probably, the disappearance of the dinosaurs, or a violent cooling of the planet …

Regularly, alerts in the cataclysm come into sight, who end generally in the admission of an erroneous calculation. But the researchers work hard to find a way to avoid a planetary disaster. As this young Australian seeker who has just won price “to Move an asteroid 2008 ″, organised under the aegis of Space Generation, an organisation which represents students and young researchers to the UNO.

Far from cannons laser, and other atomic explosions of some futuristic plans, Mary D' Souza offers simply to wrap the asteroid 99942 Apophis, an object 270-metres in diameters which should cross near the Earth in 2029. Wrap, or more precisely cover the half of Apophis of a film of Mylar which reflects light. In that way, the radiation pressure exercised by the sunlight would be changed, enough to divert the trajectory of the asteroid and to protect the Earth (or its Moon). At present, Apophis goes for a walk behind the sun. He should again be visible, for the astronomers, in 2011, what will be a chance to prove if the predictions of trajectories are correct or erroneous.

• In knowledge more on Apophis, on the site of Nasa (in English)

Picture: The only picture of Apophis, seen by the telescope American radar of Arecibo © Nasa