Dec 6 2006
From The Space Library
Scientists published research based on photographs taken by NASA’s Mars Global Surveyor (MGS). The images revealed the strongest evidence to date of occasional flowing water on the surface of Mars. MGS had begun orbiting Mars in 1997. NASA had used MGS repeatedly, to capture images of hundreds of sites on Mars, although in November 2006, NASA had announced that Surveyor’s mission was likely at an end. A team of scientists led by Michael C. Malin of Malin Space Science Systems in San Diego, California, had compared MGS images taken in 2004 and 2005 with previous MGS images and had discovered sediment deposits in two gullies on Mars. The deposits had not been present in earlier MGS images of the site, suggesting that water had carried the sediment through the gullies at some point in the previous seven years. However, because of Mars’s thin atmosphere and cold temperatures, liquid water is unlikely to remain on the planet’s surface. The researchers hypothesized that water emerging from an underground source could remain in a liquid state long enough to transport debris down a slope before freezing. Scientists consider liquid water necessary for the existence of life and believe that its presence on Mars would indicate the possibility of microbial life on that planet.
NASA, “NASA Images Suggest Water Still Flows in Brief Spurts on Mars,” news release 06-361, 6 December 2006, http://www.nasa.gov/home/hqnews/2006/dec/HQ_06362_Water_on_Mars.html (accessed 8 June 2010); Michael C. Malin et al., “Present-Day Impact Cratering Rate and Contemporary Gully Activity on Mars,” Science 314, no. 5805 (8 December 2006): 1573–1577, http://www.sciencemag.org/cgi/content/abstract/314/5805/1573 (DOI 10.1126/science.1135156; accessed 8 June 2010).
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