Asteroids directly threaten Earth, after all

Approximately twice a year, an asteroid collides with the Earth's atmosphere, having power equivalent to the burst of a Hiroshima atomic bomb. These, even, are small eruptions, as scientists state. The space rocks usually evaporate before they can cause any damage.

When a big rock hits, we might not be as lucky. Researchers at a recent gathering of the American Society for the Promotion of Science warned that it is inevitable that an asteroid big enough to penetrate the Earth's atmosphere, will at some point, hit the planet.

When this happens, there is the possibility that the asteroid is as devastating as the six-mile rock which all but wiped out life from the planet 65 million years ago.

Although the chances of a single asteroid hitting the globe are quite few, there are thousands of potential "planet killers" hidden in the asteroid belt between Mars and Jupiter.