Collision Course? Comet 2013 A1 is heading for Mars

Comet 2013 A1 is heading for Mars, and there is a chance that it might hit the Red Planet in October 2014.

Current solutions put the odds of impact at 1 in 2000.

The nucleus of the comet is probably 1 to 3 km in diameter, and it is coming in fast, around 56 km/s (125,000 mph).

If it does hit Mars, it would deliver as much energy as 35 million megatons of TNT.

An impact wouldn't necessarily mean the end of NASA's Mars program. But it would transform the program- along with Mars itself.