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Comet is heading for a close encounter with Mars

Jenny Winder, News Writer
Mar 12, 2013, 7:00 UTC

Sen—A recently discovered comet is heading for a close fly by of Mars in October 2014 according to astronomers.

According to the Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, California, comet C/2013 A1 (Siding Spring) will pass within 186,000 miles (300,000 kilometers) of Mars and there is a strong possibility that it will pass much closer. The NEO Program Office's current estimate suggest it could pass as close as 31,000 miles (50,000 kilometers) from Mars' surface. That distance is about two-and-a-half times that of the orbit of outermost moon, Deimos.

The comet was discovered on January 3, 2013, by Robert McNaught at the Siding Spring Observatory in Australia. The snowball-like mass of ice and dust spent billions of years orbiting in the deep freeze of the Oort Cloud, a spherical cloud of comets surrounding our Solar System. At some point, it got knocked out of this orbit and onto a course that brings it closer to the Sun. Sunlight has warmed the comet, causing it to shed ices and dust in a long tail.

Further refinement to its orbit is expected as more observational data is obtained. At present, Mars lies within the range of possible paths for the comet and the possibility of an impact cannot be excluded. However, since the impact probability is currently less than one in 600, future observations are expected to provide data that will completely rule out a Mars impact.

Though potential impact with spacecraft orbiting Mars is unlikely, the resulting meteor shower caused by the comet's debris could be more worrisome, both for Mars orbiters and perhaps even rovers on the surface.

This computer graphic depicts the orbit of comet 2013 A1 (Siding Spring) through the inner solar system. Image credit: NASA/JPL-Caltech

This computer graphic depicts the orbit of comet 2013 A1 (Siding Spring) through the inner solar system.  Image credit: NASA/JPL-Caltech.

"Can you imagine the views from the surface, the rovers are in for a treat the like of which I suspect NASA had never imagined" said Nick Howes, Pro Am Programme Manager for the Faulkes Telescope project, and a research associate for the Lowell LARI project on Trans Neptunian Objects (TNOs).

"It's also interesting to see if any of the agencies with orbiting spacecraft at Mars will need to factor in the coma/dust hazard of this comet, probably not, but still an interesting thought. And the images from orbit of the comet and the red planet will be spectacular."

During the close Mars approach the comet will likely achieve a total visual magnitude of zero or brighter, as seen from Mars-based assets. From Earth, the comet is not expected to reach naked eye brightness, but it may become bright enough (about magnitude 8) that it could be viewed from the southern hemisphere in mid-September 2014, using binoculars or small telescopes.

Nick told Sen, "It does also show how fragile we are, this comet could have hit Mars with extinction level consequences if there were life, something this size hitting our planet, would be catastrophic, and our governments really need to start thinking about this scenario, as one day, maybe in a few years, maybe a thousand, maybe a million, but one day, it will happen."