They discovered Neptune in 1846, by examining the orbits of the other gas giant planets, particulary Uranus. Its slight deviation in orbit was as a result of neptunes gravitational effect.
Astronomers observing the the planet Uranus found that its orbit exhibited small changes that could not be explained by interactions with the other known planets.
A couple of scientists then worked out where an unknown planet would need to be to produce the observed changes, and lo and behold, when someone looked there they found Neptune near the predicted position. Neptune was discovered as a result of a mathematical prediction.Astronomers noted that Uranus was not quite following the orbit predicted for it. They hypothesized that the gravity of an unseen planet was affecting Uranus's orbit.
Astronomers were prompted to look for Neptune by the deviation of Uranus from its orbit.
Newton's Law of Gravity resulted in calculations that explained discrepancies in the motion of Uranus and Saturn. By working out where and how large the mass had to be, scientists predicted both Neptune and Pluto with extreme accuracy.
Mathematicians predicted where it would be, based on the "perturbations" of the orbit of Uranus.
Then astronomers used telescopes to search in that area and they soon found
a planet.
Unexpected changes in the orbit of Uranus.
I don't know I just thought it was fun
Johann Gotfried Galle
Neptune. Calculations played a part in the discovery of Pluto as well, though in that case the calculations were actually incorrect. Pluto just happened to coincidentally be near the predicted region, and was found only because people were studying that area in particular detail.
A telescope.
It orbits Neptune in the opposite direction of Neptune's rotation.
Neptune was predicted by astronomers be observing the effects of its gravity. Neptune was discovered in 1846 by Johann Gottfried Galle.
neptune's gravitational effect on the orbit of uranus
Astronomers had noticed unexpected changes in the orbit of Uranus: the only explanation was another planet. Detailed study of the orbit of Uranus led to estimates about the size and location of Neptune.
Neptune. Calculations played a part in the discovery of Pluto as well, though in that case the calculations were actually incorrect. Pluto just happened to coincidentally be near the predicted region, and was found only because people were studying that area in particular detail.
A telescope.
It orbits Neptune in the opposite direction of Neptune's rotation.
Neptune was predicted by astronomers be observing the effects of its gravity. Neptune was discovered in 1846 by Johann Gottfried Galle.
neptune's gravitational effect on the orbit of uranus
The 8th planet : Neptune.
Astronomers now realize that Pluto does not have nearly enough mass to noticeably affect the orbits of Uranus or Neptune.
Neptune
The god of oceans and seas.
Neptune
Irregularities in Uranus's orbit.