Pluto's 'Thick' Air Isn't Going Anywhere
This was predicted because the distant world was passing its summer season and heading out billions of miles farther from the sun along a highly elliptical orbit. The warning worked. Launched in 2006, NASA’s New Horizons probe is now sprinting toward a 2015 rendezvous with Pluto as the fastest manmade object ever built.
ANALYSIS: Pluto’s Atmosphere: Big, Poisonous and Comet-like
But don’t worry if the long distance runner doesn’t get there soon enough. New observations by Catherine Olkin of the Southwest Research Institute in Boulder, Colo., predict that the tenuous nitrogen-methane-carbon monoxide atmosphere will remain buoyant year ’round. In fact, as Pluto enters late summer, the atmosphere is now three times denser than when first measured in 1988. That means it isn’t going anywhere.
These results provide insights into the nature of Pluto’s surface crust, say the researchers. To explain the atmospheric changes there must be a rock-hard water-ice surface that apparently soaks up feeble sunlight and holds onto the heat it for a long time.
Some astronomers have previously dismissed Pluto as an oversized comet nucleus. A comet forms a temporary atmosphere, called a coma, when it is close enough to the sun for surface ices to warm and sublimate. Some scientists called Pluto’s atmosphere just a giant and temporary coma. But comets have frothy surfaces that lose heat quickly and Pluto doesn’t according to the researchers.
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Although billions of kilometers from the sun, frigid Pluto has an Earthly air: an atmosphere made mostly of nitrogen, the same gas that constitutes 78 percent of the air we breathe. But Pluto pursues such an elliptical orbit around the sun that all of that gas might freeze onto its surface when farthest and coldest.
( via news.discovery.com )
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