Monthly Archives: February 2012

Ice cap winds spread polar gypsum

The north polar cap of Mars is surrounded by a vast dune field, about as large as Earth’s Kalahari Desert, that contains extensive deposits of gypsum. The gypsum’s origin has been debated since the mineral was discovered in 2005, yet … Continue reading

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Water-carved channels on crater debris

Medium-size craters less than 3 billion years old often show water-carved channels in their debris aprons, according to a new study of mid-latitude craters in Arabia Terra. Previous studies had reported that such features on ejecta aprons were rare. Nicolas … Continue reading

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Phoenix lander soil: dry for a long, long time

NASA’s Phoenix  spacecraft landed on the high northern plains of Mars. Among its instruments were optical and atomic-force microscopes. A team of scientists led by Tom Pike (Imperial College, London) used these to measure the size and number of particles … Continue reading

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What turned off the Martian magnetic field?

For roughly the first 500 to 800 million years of its existence, Mars had a magnetic field generated by a natural internal dynamo. This was powered by convection currents in the planet’s molten iron core, which operated vigorously as they … Continue reading

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