An oxygen atmosphere has been found on Saturn's second largest moon, Rhea, astronomers announced Thursday. The 932-mile-wide ice-covered moon is more than 932 million miles from Earth and the average surface temperature is -292 degrees Fahrenheit. At less than 62 miles thick, the newfound oxygen layer is so thin that, at Earthlike temperatures and pressure, Rhea's entire atmosphere would fit in a single midsize building. Still, the discovery implies that worlds with oxygen-filled air may not be so unusual in the cosmos. Rhea's oxygen atmosphere is believed to be maintained by the ongoing chemical breakdown of water ice on the moon's surface, driven by radiation from Saturn's magnetosphere. Knowing where and how oxygen exists in the universe may in turn help scientists plan future robotic and manned missions. NASA's Cassini spacecraft also identified the distinctive chemical fingerprint of carbon dioxide in Rhea's atmosphere, indicating the presence of carbon on the moon's surface. The combination of carbon and oxygen holds implications for finding possible life on ice moons, such as Europa, thought to harbor subsurface liquid oceans. This discovery is extremely useful when thinking ahead into the future because frozen reservoirs of oxygen on moons such as Rhea may one day become pivotal for deep-space exploration involving human missions. And in some very distant future, one can imagine that the ices on these moons might be heated or melted to extract oxygen and carbon dioxide, both of which are necessities for the survival of plant and animal life.
Link to site: http://news.nationalgeographic.com/news/2010/11/101125-saturn-moon-oxygen-atmosphere-discovered-science-space/
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