On the 15th February 2013, a meteor exploded over Russia. The atmosphere absorbed most of the object's energy, with a total kinetic energy, before atmospheric impact, equivalent to approximately 500 kilotons of TNT (about 1.8 PJ), 20–30 times more energy than was released from the atomic bomb detonated at Hiroshima.
If a large enough asteroid hits the earth, it could wipe out human life. If it hits the sea, it could cause a huge worldwide tsunami. If it hits land it could knock up enough dust into the atmosphere to block out the sun. Some people say that if we know where all the asteroids are in the solar system then we can knock them out of the way if they start coming towards the Earth.
The problem with this is:
- If we miss, it's still going to hit the Earth.
- We may not see it in time to act.