The Astronomy of Neptune

Astronomers had been observing the newly discovered planet of Uranus for 75 years. But theorists began to notice that its position did not match Newton's laws. By 1840s, two theorists were able to deduce there was another more distant planet. Adams and Laverier were able to predict the position of this new planet. They urged astronomers at observatories to which they had connections to search for it. Neptune is too faint to be seen by the naked eye no matter how good your eyes are. It could only have been discovered with the telescope. The discovery required a tremendous refinement in observational tools introduced by Galileo and the theoretical tools introduced by Newton.