The Biggest Dust Storms in 30 Years
The biggest dust storms in 30 years have been raging since June on Mars, obscuring the planet's surface, and heating the upper reaches of the thin Martian atmosphere by up to 80 degrees and cooling the surface layers 10 degrees below normal, astronomers reported Thursday.
From an Earthly perspective, the global impact of the storms is roughly equivalent to the impact of the 1991 Mount Pinatubo volcanic eruption in the Philippines that carried ash and dust around the world. "The magnitude of that eruption, its cooling of the Earth, its slight impact on the El Nino cycles is about the same scale as this dust storm," said Michael Malign, developer of the visible light camera on NASA's Mars Global Surveyor spacecraft. "But on Earth, it takes a large volcanic eruption or a place that that kind of energy can be deposited, whereas on Mars, it appears that somehow just solar heating can trigger these phenomena."
NASA on Thursday unveiled dramatic before-and-after views of Mars as seen by the Hubble Space Telescope and instruments aboard the Mars Global Surveyor, which has been in orbit around Mars since late 1997. Time-lapse movies show Cartier Replica how huge dust storms first developed in the Hellas Basin, a 6-mile-deep, 1 300-mile-wide depression in the planet's southern hemisphere that was caused by an ancient asteroid impact. In a matter of days, dust blown into the Martian stratosphere by the Hellas storms apparently affected local conditions enough to trigger outbursts in other regions.
In the Clarita's/Syria region, the winds blew for three full months. Precise wind speeds aren't known, but Malign estimated average velocities of 60 mph to 80 mph with higher gusts. "Imagine a hurricane parked off Florida for 90 days, just staying there and pumping winds and waves into the coast and shoreline of Florida," Malign said. "That's the equivalent here. This storm was blowing for every day for 90 days."
Regional dust storms aren't unusual on Mars, but scientists don't understand what triggers the evolution of global storms like the ones seen this summer. "What's remarkable about these storms is the time scale, the quick succession in which things happen, in which things that are local can become regional and then global in days or weeks rather than months or years, " said Richard Zurek, an expert about the Martian Cartier Replica Watches atmosphere who works at NASA's Jet Propulsion Laboratory. "And that's one of the aspects of these storms that we want to understand. It's a challenge to our models to try to deal with it."
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