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Atmospheric Temperature

In the earlier discussion of Uranus' seasons, it was mentioned that a unit surface at the poles will receive about 1.5 times as much sunlight as the same surface would on Uranus equator over a Uranian year. Based on this, one might expect Uranus' south polar region, which at the time of the Voyager 2 flyby had been in continuous sunlight for the order of 20 years, to be warmer than its equatorial region, which would be warmer than the north polar region, which had been in prolonged night. Voyager 2's infrared instruments did not observe this; at the level of clouds in Uranus' atmosphere, the temperature seemed to be the same, about -346°F (-210°C), from the south pole across the equator to the north pole. The most evident temperature change at this level was a 34°F (1°C) decrease centered at about 30° south latitude. This surprising observation shows the great capacity of the enormously thick atmosphere of Uranus (and those of the other Jovian planets) to absorb and transport away almost all the sunlight energy from a region sunlit continuously for decades.

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Science EncyclopediaScience & Philosophy: Two-envelope paradox to VenusUranus - Observations From Earth, Results From The Flyby Of The Voyager 2 Spacecraft, Uranus's Magnetic Field - Discovery, Puck