Neptuneplanet

Neptune (planet) is that planet in the solar system which is farthest from the sun, the distance between the two bodies being about 2,750,000,000 miles. At this immense distance it will, according to Kepler's laws (q.v.) take a long time to travel once round its orbit, and this time has been found to be 165 of our years. Although it is 97 times as large as the earth, yet, on account of its enormous distance from us it can only just be seen, even with a tolerably powerful telescope. Until the middle of the present century Neptune was considered as a star, but in 1846 Adams and Leverrier considered that a variation in the motion of the planet Uranus must be due to an undiscovered planet. From the disturbance of Uranus they were able to calculate the size and position of this new planet, and from their data Galle was led to its actual discovery by the telescope. Lassell has found that Neptune possesses one satellite, which moves round the planet in rather less than six days and is 222,000 miles away from it. No appearances in Neptune have enabled astronomers to calculate its rotation about its own axis, but it is extremely probable that it does rotate and that this motion is in the same direction as its motion round the sun.