Siding Spring comet misses Mars but near misses with Earth still possible

20 Oct 2014

The Siding Spring comet as taken on 11 October by Pal Brlas.

After much anticipation, the Siding Spring comet made its close fly-by of Mars but scientists now fear that last year’s ending of the comet spotting programme could lead to an earthbound comet being missed.

Going by its scientific name, comet C/2013 A1, this latest celestial chunk of ice and rock made, in space terms, a close fly-by of our red neighbour at a distance of 139,500km from the planet as it travelled somewhere in the region of 56km per second.

However, despite the perceived distance between the two, when put into perspective the distance is equivalent to less than half the distance between Earth and our moon and less than one-tenth the distance of any known comet flyby of Earth.

The path taken by Siding Spring as it buzzed the Red Planet. Simulation via the Near-Earth Object (NEO) office at NASA’s Jet Propulsion Laboratory.

The comet was named after the observatory that found it, that being Siding Spring observatory in New-South Wales in Australia that had been the southern hemisphere’s dedicated comet spotter to track objects of its size through our solar system.

Given the opportunity, NASA trained its three spacecraft orbiting Mars – MAVEN, Odyssey and the Mars Reconnaissance Orbiter – on the comet but also had to make sure that they were not in harms’ way of the tonnes of dust that would be emitted by the comet.

Siding Spring comet image via James Willingham, Flickr.

Danger for Earth in the future

However, there are now grave fears that a similar comet with a course putting it in Earth’s line of fire could be missed because our entire southern hemisphere is now lacking a comet watching programme.

Last year, Siding Spring observatory were forced to end its comet tracking programme due to lack of funding and withdrawal of support from the Australian government following a cut of AUS$111m in the country’s budget for its scientific endeavours.

With its closure, half of the Earth will be left in the dark over whether the estimated 1,500-plus objects with a trajectory that could be heading to our planet could be missed.

Speaking to Australian media astronomer at the Australian National University (ANU) and University of California Berkeley, Bradley Tucker, said: “It’s a real worry. There could be something hurtling towards us right now and we wouldn’t know about it.”

The Siding Spring comet as taken by the Hubble space telescope. Image via NASA, ESA, and J.-Y. Li (Planetary Science Institute).

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Colm Gorey was a senior journalist with Silicon Republic