A few days ago, 13 year-old German Nico Marquardt seemed to have embarrassed all NASA scientists when he announced that the odds of asteroid Apophis hitting the Earth in 2036 have been greatly underestimated. The funny thing is that many sources rushed to state that NASA and the ESA confirmed the schoolboy's results, only to be refuted several days later. According to NASA, the calculations made by Marquardt are generally correct, but they contain highly exaggerated presumptions and a fair number of errors.

Asteroid Apophis, discovered in December 2004, measuring about 270 meters across, will make three close approaches to our planet in 2029, 2036 and 2037. Upon its discovery, Apophis marked a four on the Torino scale - measuring the threat posed to near-Earth objects - and a chance of 1 in 37 to hit Earth in 2036. In case of an impact, it would release an energy equivalent to 100,000 Hiroshima nuclear explosions, which would determine effects upon the whole planet.

However, later calculations of its trajectory lowered the possibility of an impact to 1 in 45,000 in 2036, and to 1 in 12.3 million in 2037. According to Marquardt's calculations, the chance that Apophis would hit Earth in 2036 rise to 1 in 450, when taking into account the 40,000 artificial satellites orbiting around Earth at altitudes up to 36,000 kilometers. If Apophis were to collide with one of these satellites, its course would be altered enough to send it on a collision course with our planet in 2036.

The problem is that, although Apophis is expected to pass at a distance of only 32,500 kilometers in 2029, most of the satellites orbiting around Earth have altitudes of only 300 to 2000 kilometers. The geostationary satellites, on the other hand, are mostly located in orbits at 42,100 kilometers away from Earth, therefore the risk that Apophis will hit any of these spacecrafts is minimum.

Hitting a satellite will probably inflict little alteration in the trajectory of the asteroid; however, since its movement is governed by gravity, it may still be put in a collision course with Earth if it passes through a 600 meters gravitational keyhole in 2029.

NASA's calculations are already full of huge errors, albeit the estimations cannot be improved until 2011, when the precise orbit of the asteroid is plotted.