Mars is known for its dust storms and these storms can be huge, encircling the entire planet. On smaller scales, the Martian surface is peppered with countless dustdevils that zigzag across the red planet’s plains, kicking up dust and feeding into a unique atmospheric “dust cycle.”
As photos from the surface and orbit have shown us, the principal erosion process on Mars is aeolian — in other words, wind-driven. Vast dune fields, intricate rock formations and hazy skies attest to this dry, windy world’s nature.
Naturally, science fiction has been quick to jump on the often dramatic storms that, from a distance, look terrifying. Great walls of dust dwarfing the biggest dust or sand storms Earth can muster; bolts of lightning fueled by atmospheric friction; terrible hurricane-force winds that rip up anything in their path, stranding astronauts and destroying hardware…
Alas, the realities of Martian dust storms are a little more subtle, a fact that NASA wants to make clear ahead of the highly-anticipated general release of the Ridley Scott movie, “The Martian.”
The movie, based on the best seller by author Andy Weir, is set in the near future during a manned expedition to Mars. A fierce dust storm causes the mission to be abandoned as the astronauts’ base station is damaged and one of the crew, Mark Watney (played by Matt Damon) is lost, presumed dead, after being hit by debris, blown away and partially buried by the terrible Martian winds.
But that scene, among others in countless sci-fi imaginings of the Martian environment, is a little misleading, according to NASA scientists, and it all comes down to atmospheric pressure.
Although dust storms on Mars come with their hazards, it’s highly unlikely that any storm would be powerful enough to strand astronauts on the surface or rip apart equipment. The strongest Mars winds top out at around 60 miles per hour (less than 30 meters per second), less than half the speed of hurricane-force winds on Earth. But it’s not the speed of a wind that does the damage, it’s atmospheric pressure, something that Mars is somewhat lacking. The planet’s atmospheric pressure is around 1 percent that of Earth’s, which is a serious bummer if you wanted to fly a kite on the Red Planet.
“The key difference between Earth and Mars is that Mars’ atmospheric pressure is a lot less,” said physicist William Farrell, of NASA’s Goddard Space Flight Center in Greenbelt, Md., who studies atmospheric breakdown in Mars dust storms. “So things get blown, but it’s not with the same intensity.”
Although even the most savage dust storm on Mars would likely be the equivalent of a gentle breeze on Earth, Mars dust storms will still cause a problem for our future astronauts, especially if they are dependent on solar power.
In The Martian, Watney spends time every day cleaning solar panels to avoid dust buildup. As has been experienced by our solar powered Mars rovers — particularly NASA’s veteran Mars Exploration Rover, Opportunity, that continues to rove over a decade after landing on Mars — this is a very real problem that could seriously limit the collection of solar energy. Also, as the atmosphere becomes filled with fine dust during these storms, the quantity of sunlight reaching the surface is impeded.
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SOURCE: Discovery News, Ian O’Neill