Mars in 3-D New images from the Mars Reconnaissance Orbiter show the Red Planet's surface in extraordinary detail--and in three dimensions to boot. The photos, known as anaglyphs, come from the orbiter's High Resolution Imaging Science Experiment, or HiRISE, billed as the most powerful camera ever placed in another planet's orbit.
Researchers have found new evidence that the atmosphere of Mars is being stripped away by solar wind. It's not a gently continuous erosion, but rather a ripping process in which chunks of Martian air detach themselves from the planet and tumble into deep space. This surprising mechanism could help solve a longstanding mystery about the Red Planet.
"It helps explain why Mars has so little air" - David Brain of UC Berkeley, who presented the findings at the 2008 Huntsville Plasma Workshop on October 27th.
Some researchers believe the atmosphere of Mars was once as thick as Earth's. Today, however, all those lakes and rivers are dry and the atmospheric pressure on Mars is only 1% that of Earth at sea-level. A cup of water placed almost anywhere on the Martian surface would quickly and violently boil awaya result of the super-low air pressure. So where did the air go? Researchers entertain several possibilities: An asteroid hitting Mars long ago might have blown away a portion of the planet's atmosphere in a single violent upheaval. Or the loss might have been slow and gradual, the result of billions of years of relentless "sand-blasting" by solar wind particles. Or both mechanisms could be at work. Brain has uncovered a new possibility--a daily ripping process intermediate between the great cataclysm and slow erosion models. The evidence comes from NASA's now-retired Mars Global Surveyor (MGS) spacecraft.