Though the discrepancies were small, there was a difference between the observed orbit of Uranus and the way Newtonian physics predicted its orbit to be. In July, Le Verrier proposed that the difference could be explained by another planet beyond Uranus, and made predictions as to the orbit of this previously unknown body.
Being a mathematician first and an astronomer second, he wasn't really interested in finding it with a telescope now that he'd found it in maths, and the task of searching for it was left to German astronomer Johann Gottfried Galle. On September 23, 1846, Galle looked at the spot Le Verrier had predicted the planet would be, and found to within 1 degree of the spot... the planet Neptune.
So, having discovered a new planet by looking at the orbit of another, Le Verrier was called upon to take a look at a planet whose name doesn't also mean butt hole: Mercury. Mercury, being so close to the Sun, is the most difficult planet in our Solar System to observe (assuming there is no Planet Nine out there). Le Verrier was tasked with plotting Mercury's orbit using Newtonian physics.
But he couldn't. No matter how much he tried, Mercury's eccentric orbit didn't make any sense. According to Newtonian theory, the planets move in elliptical orbits around the Sun, but observations showed that Mercury's orbit wobbles more than could be accounted for by the gravity exerted by the other known planets. TO READ MORE, CLICK HERE...
