Neptune, the eighth planet in our solar system, was discovered through mathematical predictions based on the observations of Uranus. Here's the story of Neptune's discovery:
In the early 19th century, astronomers noticed that Uranus, which had been discovered by William Herschel in 1781, did not follow its predicted orbit accurately. Its actual position deviated slightly from the calculated position. These irregularities suggested that there might be another planet exerting gravitational influence on Uranus.
Two mathematicians, Urbain Le Verrier from France and John Couch Adams from England, independently set out to determine the location of the hypothetical planet. Using complex mathematical calculations, they predicted the existence and approximate position of the unknown planet. Their work was done independently, with Adams publishing his predictions in 1846, while Le Verrier's findings were published a few months later.
Using the predictions of Le Verrier and Adams, astronomers embarked on the search for the elusive planet. Johann Galle, a German astronomer, received a letter from Le Verrier containing the predicted location of the unknown planet. On the night of September 23, 1846, Galle and his assistant Heinrich d'Arrest used a telescope at the Berlin Observatory to search for the planet.
Within an hour of their search, Galle and d'Arrest identified a small dot of light in the expected location. This observation confirmed the existence of Neptune. The discovery was hailed as a major triumph of celestial mechanics and a validation of Newton's laws of gravitation.
It's worth noting that there was some controversy surrounding the discovery of Neptune. Both Le Verrier and Adams claimed credit for predicting the planet, and there was a dispute over priority. Eventually, it was recognized that both mathematicians had made significant contributions to the discovery of Neptune.
In summary, Neptune was discovered through mathematical calculations and predictions based on the observed irregularities in Uranus' orbit. The actual planet was then observed and confirmed by Johann Galle and Heinrich d'Arrest at the Berlin Observatory in 1846.