Asteroids and the threat to Earth

The question of what action to take when there is the possibility of an asteroid collision with the Earth periodically surfaces from time to time in science and astronomy circles. With impact craters clearly visible on most continents (and most recently discovered in the Yukatan Peninsula in the Gulf of Mexico) and the theory that an asteroid strike led to the demise of the dinosaur age (at the end of the Cretaceous period), this matter is one which won't disappear. The options of how to prevent a collision are not numerous but in practical terms only a handful have any chance of success. Asteroid Ida (pictured) is 35 klms in length and is located in the asteroid belt and does not cross Earth's orbit but represents the size and scale of many of these bodies floating in relatively nearby space.

One option often canvassed is to actually destroy an asteroid through the detonation of a nuclear device below the surface however the most obvious pitfall is without knowing precisely the composition and density of the material, the only result may be to splinter the asteroid and create additional possible impacts on the Earth. More favourably considered are strategies of 'nudging' an asteroid away using nuclear explosions in near proximity or alternatively a concentrated range of laser beams using solar power from reflected rays of the sun with the same effect.

Whatever the possible solutions may be, the principal concern is to be able to actually detect an asteroid before it's too close. In that respect space surveillance programs have fallen on hard times and its more luck than intention when an asteroid is located travelling nearby.