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24 April 2014 11:45 am ,
Vol. 344 ,
Major climate data sets have underestimated the rate of global warming in the last 15 years owing largely to poor data...
The tsetse fly is best known as the vector for the trypanosome parasites that cause sleeping sickness and a disease in...
The National Institutes of Health is revising its "two strikes" rule, which allowed researchers only one chance to...
By stabilizing the components of retromers, molecular complexes that act like recycling bins in cells, a recently...
Fossil fuels power modern society by generating heat, but much of that heat is wasted. Semiconductor devices called...
Researchers are gaining insights into what made Supertyphoon Haiyan so powerful and devastating through post-storm...
Millions around the world got a first-hand look at what it was like to be in Tacloban while it was pummeled by...
- 24 April 2014 11:45 am , Vol. 344 , #6182
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ScienceShot: Mystery of Mars Polar Pinwheel Unraveled
26 May 2010 1:09 pm
Something strange has happened to Mars's polar ice cap. Instead of a uniform, roughly circular blob, like on Earth, the Martian version resembles a pinwheel (left), with dry, spiral troughs separating the ice sheets. There's also Chasma Boreale, the deep, dagger-shaped gouge that cuts across the pinwheel. Scientists had thought that the canyon, which is 2 kilometers deep, was carved by some catastrophic flood in the distant past. Now in two papers published tomorrow in Nature, researchers think they have solved both mysteries. Using a radar survey of the pole (right), which peered under the ice, they conclude that Chasma Boreale wasn't dug out at all. Instead, Martian winds built up the steep, canyon-like walls over millions of years. As for the pinwheel, the team reports that it likewise formed over many millennia, as strong winds pushed apart the dry ice crystals on the surface, much like winds on Earth create sand dunes.
See more ScienceShots.