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
Provisional designation in astronomy Planet Center's website does not state how the packed form for minor planets will change when the numbering reaches 620,000. The current total of numbered minor planets can be found at MPC's statistics page, in column "numbered" of section "Orbits And Names". Provisional designation in astronomy Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been calculated. In the case of more than 750,000 minor planets, approximately a third remains provisionally designated, as hundreds of thousands have been