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Astronomers once thought Pluto's atmosphere would condense down to the surface as it moved away from the Sun. Can that still be true, and if so, is that causing the surface features we now see?

David McKay, Sea Isle City, New Jersey
RELATED TOPICS: PLUTO
As the Sun shines on Pluto's dayside, it turns ice to vapor.
We now know for sure that Pluto’s atmosphere does change greatly over time, since we’ve seen it more than double since 1988. This is almost certainly because the atmosphere — which is nitrogen, like Earth’s atmosphere — is also frozen as ice on the surface. If the nitrogen ice warms by just a degree, then the atmospheric pressure increases 80 percent.

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