The remotest planet of the solar system at present known; it is twice as far distant from the sun as Uranus is, deemed before its discovery the remotest; its diameter is four times greater than that of the earth, and it takes 60,126 days to revolve round the sun, accompanied by a solitary satellite; it was discovered in 1846 by Adams and Leverrier, who were guided to the spot where they found it from the effect of its neighbourhood on the movements of Uranus.