German astronomer Johann Gottfried Galle discovered the planet Neptune at the Berlin Observatory on this day in September 23, 1846.
The existence of Neptune, the eighth planet generally from the Sun, was postulated by French astronomer Urban Jean-Joseph Le Verrier who calculated the approximate position of the planet by studying gravitational perturbations in the motions of Uranus, according to History.
On September 23, 1846, Le Verrier reported his findings to Galle, and on the same night Galley and his assistant Heinrich Louis Darest identified Neptune at their observatory in Berlin, observing its motion relative to the background stars over a 24-hour period, as it was confirmed to be a planet.
The blue gas giant, with a diameter four times the diameter of the Earth, was named after the Roman god of the sea. After that, several information was known about it, including that it has eight known moons, the largest of which is Triton, and a ring system that contains three bright rings and two faint rings as it completes its orbit around the sun once every 165 years old, and in 1989, the American spacecraft Voyager 2 was the first human spacecraft to visit Neptune.
And the planet Neptune is the only planet in the solar system that has been discovered through equations and mathematical prediction. The unexpected changes in the orbit of the planet Uranus led astronomers to conclude that the gravitational disturbance is caused by an unknown planet located behind it, and the planet was discovered one degree away from the expected location through the mathematical equations.