10 Oct 2016

Blustery dust storm to shroud Mars in a few weeks

101016_marsduststorm_1THE PLANET MARS arrives at Perihelion on 29 October, and remains visible in the evening sky during the remainder of this year. Shining at Mag +0.4, It is rather low in the sky lying in the constellation of Sagittarius at the moment, then Mars moves into Capricorn on 8 November, and  into Aquarius on 16 December.

Its apparent size is getting smaller from 8.1” on 15 October to 5.66” at the end of the year. Its elongation from the Sun decreases from 79 degrees to 57 during the same period.

NASA is predicting a new significant dust storm will happen on Mars in a weeks ahead, a big one should strike in the next few weeks or months, lending weight to a Martian dust storm forecasting system.

A 2015 study in Icarus by James Shirley, a planetary scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, found Mars' dust storm season midpoint is the end of October.  Which is when ESA’s  ExoMars arrives at the red planet, and the small Schiaparelli lander descends onto the Martian surface.

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"Based on the historical pattern we found, we believe it is very likely that a global dust storm will begin within a few weeks or months of this date," Shirley says.

The most recent Martian global dust storm blew up in 2007. The rovers Spirit and Opportunity were starved of solar power.

So how do these global storms arise?

Dust storms are part of everyday life on the red planet. Local eddies and whirls can join forces to become bigger storms – perhaps producing lightning – that can cover entire regions.

These tend to arise during the southern hemisphere's spring and summer, when Mars is closest to the sun.

Shirley calculated that the effects other planets have on Mars' momentum as it orbits the sun, along with its orbital motion, contribute to the frequency and severity of the storms.

NASA's Mars Reconnaissance Orbiter's colour camera will keep an eye on the planet, though – we'll know if Shirley's predictions come true soon enough.

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