Astronomers: Pluto colder than expected

(SPACE.com) -- Earth-bound astronomers taking Pluto's temperature have confirmed suspicions that the planet is colder than it should be. It's thought that the planet's lower temperature is the result of interactions between its icy surface and thin nitrogen atmosphere.
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http://www.cnn.com/2006/TECH/space/01/03/pluto.temp/index.html