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
Radio astronomy service responsibility of the appropriate national administration. The allocation might be primary, secondary, exclusive, and shared. In line to the appropriate ITU Region the frequency bands are allocated (primary or secondary) to the "radio astronomy service" as follows. Radio astronomy service Radio astronomy service (also: "radio astronomy radiocommunication service") is, according to Article 1.58 of the International Telecommunication Union´s (ITU) Radio Regulations (RR), defined as "A radiocommunication service involving the use of radio astronomy". Subject of this radiocommunication service is to receive radio waves transmitte by astronomical or celestical objects. The allocation of radio frequencies is provided according to "Article 5"