Mars Express reveals the Red Planet's volcanic pastMarch 17, 2008A new analysis of impact cratering data from Mars reveals that the planet has undergone a series of global volcanic upheavals. These violent episodes spewed lava and water onto the surface, sculpting the landscape that ESA's Mars Express looks down on today. Using images from the High Resolution Stereo Camera (HRSC) on Mars Express, Gerhard Neukum, Freie Universität Berlin, Germany, and colleagues are discovering the history of the Red Planet's geological activity. "We can now determine the ages of large regions and resurfacing events on the planet," says Neukum. Resurfacing occurs when volcanic eruptions spread lava across the planet's surface. This work has suggested that the sculpting of the Martian surface has not proceeded in a steady fashion, as it does on Earth. Rather, the team have discovered that Mars has been wracked by violent volcanic activity five times in the past, after the early supposedly warmer and wetter phase, more than 3.8 thousand million years ago. In between these episodes, the planet has been relatively calm. The five volcanic episodes stretch throughout Martian history, occurring around 3.5 thousand million years ago, 1.5 thousand million years ago, 400-800 million years ago, 200 million years ago and 100 million years ago. Neukum estimates that the dates of the earlier episodes are correct to within 100-200 million years and that the later dates are correct to within 20-30 million years. The ages have been estimated by counting the number of small craters that appear on the landscape. The idea is simple: the older the surface, the more craters it will have accumulated as meteorites of all sizes have struck over the ages. There has been a debate recently about the validity of this method. Some researchers believe that the small craters are not produced by incoming meteorites but by chunks of Martian rock blasted over the surface after a single large impact. However American researchers, analysing seven years' worth of images from the Mars Orbiter Camera (MOC) on NASA's Mars Global Surveyor, have found new craters appearing on the surface during that time. "The present day cratering rate can be calculated from their observations," says Neukum. It fits very closely with the cratering rate he established from the Mars Express data with Bill Hartmann, Planetary Science Institute, Tucson, Arizona, giving him confidence in the estimates. During these volcanic episodes, eruptions of lava flowed across Mars. The internal heat generated by the volcanic activity also caused water to erupt from the interior, causing wide-scale flash flooding. As for why Mars behaves like this, geophysical computer-based models suggest that the planet has been trying to establish a system of plate tectonics, as there is on Earth where the crust is broken into slowly moving plates. On Mars, the volcanic episodes represent the planet almost achieving, but not actually attaining, plate tectonics - and these volcanic episodes might not be over. "The interior of the planet is not cold yet, so this could happen again," says Neukum. Far from revealing a geologically dead world, Mars Express is exposing a place of subtle activity that could still erupt into something more spectacular. Mars Express highlights • Water on Mars (http://a1862.g.akamai.net/7/1862/14448/v1/esa.download.akamai.com/13452/podcast/water_on_mars_131006.mp4) European Space Agency |
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| Related Mars Express Current Events and Mars Express News Articles Mars, methane and mysteries Mars may not be as dormant as scientists once thought. The 2004 discovery of methane means that either there is life on Mars, or that volcanic activity continues to generate heat below the martian surface. Mountain on Mars may answer big question The Martian volcano Olympus Mons is about three times the height of Mount Everest, but it's the small details that Rice University professors Patrick McGovern and Julia Morgan are looking at in thinking about whether the Red Planet ever had - or still supports - life. Important role of groundwater springs in shaping Mars Data and images from Mars Express suggest that several Light Toned Deposits, some of the least understood features on Mars, were formed when large amounts of groundwater burst on to the surface. Mars Express observes aurorae on the Red Planet Scientists using ESA's Mars Express have produced the first crude map of aurorae on Mars. These displays of ultraviolet light appear to be located close to the residual magnetic fields generated by Mars's crustal rocks. Mars Express mission controllers ready for NASA Phoenix landing ESA's Mars Express mission control team are ready to monitor Phoenix's critical entry, descent and landing onto the Martian surface on 26 May 2008. Artificial intelligence boosts science from Mars Artificial intelligence (AI) being used at the European Space Operations Centre is giving a powerful boost to ESA's Mars Express as it searches for signs of past or present life on the Red Planet. Plan to identify watery Earth-like planets develops Astronomers are looking to identify Earth-like watery worlds circling distant stars from a glint of light seen through an optical space telescope and a mathematical method developed by researchers at Penn State and the University of Hawaii. Mars and Venus are surprisingly similar Using two ESA spacecraft, planetary scientists are watching the atmospheres of Mars and Venus being stripped away into space. The simultaneous observations by Mars Express and Venus Express give scientists the data they need to investigate the evolution of the two planets' atmospheres. Ice clouds put Mars in the shade Until now, Mars has generally been regarded as a desert world, where a visiting astronaut would be surprised to see clouds scudding across the orange sky. However, new results show that the arid planet possesses high-level clouds that are sufficiently dense to cast a shadow on the surface. Setting stars reveal planetary secrets Watching the stars set from the surface of the Earth may be a romantic pastime but when a spacecraft does it from orbit, it can reveal hidden details about a planet's atmosphere. More Mars Express Current Events and Mars Express News Articles |
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