which planet was discovered based on a calculation involving Newton's law?

Answer 1

I believe it was Pluto. Astronomers knew from the movement of the other planets that there must be something else out there, of a certain size, and a certain distance. Once they knew where to look, Clyde Tombaugh did the tedious work, taking pictures and looking them over carefully until he spotted it.

Answer 2

It was Neptune.

Pluto was discovered during a search for a planet supposedly responsible for tiny shifts in Neptune's orbit. However, now that we know Pluto's real size, we now know that whatever shifts were calculated, Pluto is way too small to have caused them.

Here is what wiki says:
Discovered on September 23, 1846[1], Neptune was the first planet discovered by mathematical prediction rather than regular observation. Perturbations in the orbit of Uranus led astronomers to deduce Neptune's existence.

It was discovered very close to the calculated position and it is of the right size and orbit to explain the shifts in the orbit of Uranus.

The calculatios had been done by LeVerrier who convinced Galle, in Germany, to search for it. By the time Galle got around to search for it, others were also searching. Galle found it because German observatories had very good star charts and were able to see if an object was an already-known star or not.

Many people (including Galileo) had seen Neptune before, but failed to recognize that it was a planet.

Answer 3

Hardly anyone remembers the planet Vulcan

(actually, the planet that was predicted, yet never was)

Answer 4

Both Uranus, Neptune, and also Pluto.

Answer 5

I think venus but don't quote me on that, i'm not 100% sure