http://www.slate.com/blogs/bad_astr...t_may_get_hit_by_a_comet_in_october_2014.html
We need a rescue mission to get Curiosity out of there!
In case you just can’t get enough impact news, it looks like Mars may actually get hit by a comet in 2014! As it stands right now, the chance of a direct impact are small, but it’s likely Mars will get pelted by the debris associated with the comet.
The comet is called C/2013 A1 (Siding Spring), discovered on Jan. 3, 2013 by the Australian veteran comet hunter Robert McNaught. As soon as it was announced, astronomers at the Catalina Sky Survey looked at their own data and found it in observations from Dec. 8, 2012, which helped nail down the orbit (I explain how that works in a previous article about asteroid near-misses). Extrapolating its orbit, they found it will make a very near pass of Mars around Oct. 19, 2014, missing the planet by the nominal distance of about 100,000 kilometers (60,000 miles).
Observations taken at the ISON-NM observatory in New Mexico just this week have tightened up the orbit a bit more, allowing for better predictions. Given this new data, the comet may actually pass closer to Mars; another veteran comet hunter, Leonid Elenin, predicts it may get as close as 37,000 km (23,000 miles) of the surface of Mars!
If the nucleus does hit the planet, well.
That will be amazing, and by “amazing” I mean “apocalyptic”. The nucleus size is not well known, but may be as small as 15 kilometers (9 miles) or as big as 50 km (30 miles). Even using the small number means Mars would be slammed by an unimaginable impact. The comet is orbiting the Sun backward (more on that in a second), so it will be moving at a speed of about 55 kilometers per second (120,000 miles per hour!) upon impact. That means the comet has a huge amount of kinetic energy, the energy of motion. That energy will be released at impact as an explosion. A big one.
A really big one.
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.
We need a rescue mission to get Curiosity out of there!