A newfound comet is apparently on course to have an exceedingly close call with the planet Mars in October 2014, and there is a chance (albeit small) that the comet may even collide with the Red Planet.

The comet (C/2013 A1) was discovered on 3rd January, 2013 at the Siding Spring Observatory, New South Wales, Australia, by Robert H. McNaught a prolific observer of both comets and asteroids who has 74 comet discoveries to his name. When establishing its path, astronomers were surprised to find that it may pass very close to or could collide with the Planet Mars in October 2014.


The C/2013 A1 comet is moving on a hyperbolic orbit in retrograde. According to the calculations based on the comet’s orbit in the past two months, C/2013 A1 will come as near as 110000 km to Planet Mars on 19th October 2014; and with a margin of uncertainty, this move towards Mars does not preclude a collision.

Ian O’Neill from Discovery Space rightly put forward that the comet has been observed, so far, for 74 days and consequently it is difficult for the astronomers to predict with precision the position of the comet in 20 months ahead.

Will planet Mars have a close brush with disaster?

C/2013 A1 is a large comet whose nucleus is about 50 km in diameter. Accordingly, if this comet is going to strike on Planet Mars, the latter will be left with a huge crater of about 500 km in diameter – a cataclysm that would make us forget the collision between comet Shoemaker-Levy 9 and Jupiter, in 1994 or even the Urals meteor shower. The trail of C/2013 A1 will be refined in the coming months.

Will the crash of C/2013 A1 on Mars be visible from Earth?

Yes! Moving at 35 miles (56 km) per second, such a collision could create an impact crater on Mars up to ten times the diameter of the comet’s nucleus and up to 1.25 miles (2 km) deep, with an energy equivalent up to of 2 x 10^10 megatons! Such a blast will be easily visible from Earth as a brilliant flash of light in the sky.

And if there’s no impact?

If C/2013 A1 eventually avoids hitting planet Mars, the comet will voyage close to the Martian soil, with a visibility magnitude of about -8 (as seen from Mars). Cameras in the MRO orbit and rovers Opportunity and Curiosity (on Mars right now) may be able to take pictures of this phenomenon (if NASA’s little robots are lucky to survive the impact of course). The comet will be visible from Earth if you have a pair of good binoculars.

While the observers are currently following C/2012 F6 Lemmon and they are also preparing for the passage of the comet Panstarrs in March, pending Ison for the end of the year, we now have this discovery that has stirred the astronomy world.

Collision or not, Comet Siding Spring will definitely come extremely close to Mars less than 20 months from now. Incredibly, this will actually be the second close shave of Mars by a passing comet within a time span of just over a year.

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