A 13-year-old German schoolboy corrected NASA's estimates on the chances of an asteroid colliding with Earth, a German newspaper reported Tuesday, after spotting the boffins had miscalculated.

Nico Marquardt used telescopic findings from the Institute of Astrophysics in Potsdam (AIP) to calculate that there was a 1 in 450 chance that the Apophis asteroid will collide with Earth, the Potsdamer Neuerster Nachrichten reported.

NASA had previously estimated the chances at only 1 in 45,000 but told its sister organization, the European Space Agency (ESA), that the young whizzkid had got it right.

The schoolboy took into consideration the risk of Apophis running into one or more of the 40,000 satellites orbiting Earth during its path close to the planet on April 13 2029.

Those satellites travel at 3.07 kilometres a second (1.9 miles), at up to 35,880 kilometres above earth -- and the Apophis asteroid will pass by earth at a distance of 32,500 kilometres.

If the asteroid strikes a satellite in 2029, that will change its trajectory making it hit earth on its next orbit in 2036.

Both NASA and Marquardt agree that if the asteroid does collide with earth, it will create a ball of iron and iridium 320 metres wide and weighing 200 billion tonnes, which will crash into the Atlantic Ocean.

The shockwaves from that would create huge tsunami waves, destroying both coastlines and inland areas, whilst creating a thick cloud of dust that would darken the skies indefinitely.

The 13-year old made his discovery as part of a regional science competition for which he submitted a project entitled: "Apophis -- The Killer Astroid."