From Earth the Uranus in study by a telescope. Within walking distance of the cloud tops and a pressure of 0.4 times that recorded on Earth at sea level the temperature is -214 ° C. The chemical composition of the uppermost layer of the atmosphere is mostly hydrogen gas while the bulk of Uranus is composed of heavy material. Uranus should be composed predominantly water ice, ammonia and methane compounds that because the most abundant elements (hydrogen, oxygen, carbon and nitrogen) are the usual ice in the solar system. Its south pole exposed to the sun for decades seemed stained with a reddish tinge; a series of concentric waves could be clearly seen in the images processed by the computer and handfuls high luminous clouds swept from east to west by winds of up to 500 km / hour.
On low temperatures these compound compress and form ice crystals clouds; methane occupies the upper layer preventing ammonia and observes the underlying water. According to the model a preponderance of the light elements should increase as we move away from the source of solar heat vaporizing. However Uranus has more heavy elements than Jupiter and Saturn and Neptune turns out to be even heavier.
At the time of the Voyager II encounter with Uranus, the Sun fell almost directly over the South Pole and North Pole had been in the dark for 20 years, while Ecuador was in permanent twilight. Solar energy distribution differed completely from that found in other planets whose axes of rotation are much less likely. Despite that atmospheric circulation was similar. Today we know that this is more influenced by the rotation of the planet governed by the distribution of solar energy.
On March 10, 1977 several groups of researchers observed the occultation by Uranus of the star SAO 158687. To calibrate their instruments began much earlier observation of the occultation, to his surprise, was intercepted starlight abruptly at short intervals before and after Uranus pass in front of the star. During the years following the observations of Uranus made during more than 200 stellar occultations by the planet revealed nine narrow rings and dark, all of which delve into a planetary radius starting from the top of the atmosphere.
The rings are designated (in order of increasing distance from Uranus): 6, 5, 4, alpha, beta, eta, gamma, delta and epsilon. The cameras of Voyager II discovered a new ring very narrow, about 100 bands almost transparent invisible from Earth. The identified ring particle range from about 10 cm to some meters while the band of dust is average of only 0.02 mm.
51,200 km diameter Diam / Earth 4.01 Earth / Earth 14.5 1.21 Density Gravity / Land 0.88 Ecuador inclination to the plane of the planet's orbit 98 ° sidereal rotation period in days, hours, minutes and seconds 17 hours, 14 minutes Distance to Sun in million km Minimum: 2,735 / Max: 3,004 / Media: 2,870 Distance to the sun in AU 19.2 Tilt the plane of the planet's orbit about the land 0 ° 46 ' sidereal period of revolution in Years, Days 84 Years and Hours / 7 Days / Hours 9 Number of satellites (the most important so far) 15