Posted by Andrew Fazekas in StarStruck on March 6, 2013

Mars may have a really bad day next year on October 19th.    That’s when there is a very slight chance a newly discovered comet may impact our neighboring planet, says NASA.

Comet C/2013 A1 (Siding Spring) was discovered by Australian Robert H. McNaught, a prolific comet and asteroid hunter just two months ago and NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory , in Pasadena, Calif., has been constantly refining the comet’s exact trajectory ever since.

Latest orbital calculations have the icy visitor passing by Mars  at only 31,000 miles (50,000 kilometers) – only two-and-a-half times the distance that the outer moon Deimos orbits.

Astronomers watching the icy interloper predict that as more observations are accumulated over time,  it’s more and more likely Mars is going to dodge the bullet and only get a close shave . The possibility of impact however has not been completely ruled out yet, says NASA, giving the comet a 1 in 600 chance of walloping the Red Planet.

If Siding Spring would hit, the force of impact may truly be monumental. Based on observations to date the comet nucleus could be a real monster – as big as 9 miles (15 km) to 31 miles (50 km) wide. With it’s velocity clocked at 35 miles (56 km) per second, the energy force of the collision could be measured in the billions of megatons, resulting in a crater hundreds of miles wide.  This could be an impact that rivals the one that wiped out the dinosaurs 65 million years ago on our planet and would be bright enough to be even seen with the naked eye from Earth.

Chances are however that it will just barely miss the planet, but comet Siding Spring may still become visible through binoculars and backyard scopes for us Earthlings in the Southern Hemisphere around mid-September 2014.  It  should also produce quite a sky show as seen from the surface of Mars. 

Current brightness magnitudes estimate that  the comet will be very bright to even the digital eyes of the two working Mars rovers – Opportunity and Curiosity. Can hardly wait to see the amazing photos from these intrepid robotic explorers!

So it will definitely be worth watching what the comet does in the coming weeks and months- whether it impacts Mars or not.

Source: http://newswatch.nationalgeographic.com/2013/03/06/monster-comet-may-have-mars-in-its-crosshairs/