In the wake of the asteroid fly-by two weeks ago, and the meteorite that slammed into Russia the same day, we now hear that Mars might possibly be hit by a comet next year. [readon]
Comet C/2013 A1 (Siding Spring) was spotted for the first time two months ago, and astronomers have now calculated that it will be within striking distance of Mars in mid-October 2014. But will it actually score a direct hit?
Right now the comet is a long way away, and ice cold. But as it enters the inner Solar System, it will start to warm up and chunks of ice and meteors will start to break away, forming a classic comet coma. If Mars passes through the coma, a huge meteor shower will rain down on it.
Another option is that these changes in the comet will alter its orbit – maybe moving it a bit further away from the planet … or, indeed, a bit closer. Which gives it a real chance of actually crashing.
If that happens, Mars will be hit by an object 20 miles wide or more, traveling at 120,000 miles an hour. On his Bad Astronomy blog, Phil Plait writes:
Doing a rough calculation, I get an explosive yield of roughly one billion megatons: That’s a million billion tons of TNT exploding. Or, if you prefer, an explosion about 25 million times larger than the largest nuclear weapon ever tested on Earth.
Watch out, Mars rover “Curiosity”!