Atmosphere of Uranus at the solstice of 1986, when "Voyager 2" passed by the planet, they were concentrated near the sunlit pole, making it dark in ultraviolet light. The outermost layer of the Uranian atmosphere, extending for thousands of kilometres, is the thermosphere/exosphere, which has a uniform temperature of around 800 to 850 K. This is much higher than, for instance, the 420 K observed in the thermosphere of Saturn. The heat sources necessary to sustain such high temperatures are not understood, since neither solar FUV/EUV radiation nor auroral activity can provide the necessary energy. The weak cooling efficiency due to the depletion
A Planet Called Utopia same reason), and temporary personal relationships favored. Diseases are nonexistent, and cures have been found for all of them. Life involves pleasure and adventure (skiing, scuba diving, parachuting, automobile racing) all day long. The population nevertheless needs an occasional birth, so couples are allowed to have children according to a lottery system, such that the number of births is exactly equal to the number of accidental deaths in a year. The protagonist, Hardy Cronyn, is the first off-worlder to be allowed onto the planet in sixty years. A lot of diplomatic arm wrestling led to the planet's agreement to let