Snapshot
February 04, 2010
This just-released image of Pluto, the most detailed ever, comes from NASA's Hubble Space Telescope and shows an icy, molasses-colored world as it experiences seasonal changes in its surface color and brightness. Pluto has become significantly redder in recent years, a mere blip in its 248-year orbit around the sun. The northern hemisphere, pointed toward the camera, has gotten brighter too. The changes are most likely due to surface ice melting on the sunlit pole and refreezing on the opposite pole. Scientists think the dramatic change in color took place between 2000 and 2002. Warming and melting nitrogen ice causes the planet's thin atmosphere to double during certain phases of its orbit. The bright spot shown here, covering much of the lower center of the planet, is unusually rich in carbon monoxide frost. This will be the sharpest image we have of Pluto until the New Horizons spacecraft flies by the planet in 2015. Speaking of flybys, NASA just extended the international Cassini-Huygens mission to explore Saturn and its moons through 2017. The agency's just-announced 2011 budget provides a $60 million-per-year extension for continued study of the ringed planet.
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