"Uranus personifying the sky" they say regarding Greek mythology... according to Greek mythology, was the great-grandfather of Ares (Mars), grandfather of Zeus (Jupiter) and father of Cronus (Saturn). Uranus has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. It is the only planet whose English name is derived directly from a figure of Greek mythology. The adjectival form of Uranus is "Uranian". The pronunciation of the name Uranus preferred among astronomers is /ˈjʊərənəs/ YOOR-ə-nəs, with stress on the first syllable as in Latin Ūranus, in contrast to /jʊˈreɪnəs/ yoor-AY-nəs, with stress on the second syllable and a long a, though both are considered acceptable. The mean apparent magnitude of Uranus is 5.68 with a standard deviation of 0.17, while the extremes are 5.38 and 6.03. This range of brightness is near the limit of naked eye visibility. Uranus's mass is roughly 14.5 times that of Earth, making it the least massive of the giant planets. Its diameter is slightly larger than Neptune's at roughly four times that of Earth. A resulting density of 1.27 g/cm3 makes Uranus the second least dense planet, after Saturn. Uranus's internal heat appears markedly lower than that of the other giant planets; in astronomical terms, it has a low thermal flux. Why Uranus's internal temperature is so low is still not understood. Neptune, which is Uranus's near twin in size and composition, radiates 2.61 times as much energy into space as it receives from the Sun, but Uranus radiates hardly any excess heat at all. Although there is no well-defined solid surface within Uranus's interior, the outermost part of Uranus's gaseous envelope that is accessible to remote sensing is called its atmosphere.
Voyager 2 flew past Uranus in 1986, giving us our first close view (of the planet). It is still functioning today as it flies in deep space, more than 10 billion miles from Earth. Voyager 2 and its companion spacecraft, Voyager 1, are returning data on how the influence of our sun wanes as they get further from it, and on the characteristics of space between the stars.
Most linguists trace the etymology the name Οὐρανός to a Proto-Greek form *Worsanós (Ϝορσανός), enlarged from *ṷorsó- (also found in Greek οὐρέω (ouréō) 'to urinate', Sanskrit varṣá 'rain', Hittite ṷarša- 'fog, mist'). The basic Indo-European root is *ṷérs- 'to rain, moisten' (also found in Greek eérsē 'dew', Sanskrit várṣati 'to rain', or Avestan aiβi.varəšta 'it rained on'), making Ouranos the "rain-maker", or the "lord of rains".
The Mutilation of Uranus by Saturn