# Definition:Neptune

## Definition

Neptune is the eighth planet of the solar system from the sun.

Its orbit lies mainly between those of Uranus and Pluto, although the latter comes closer to the sun than Neptune on part of its orbit.

## Historical Note

Neptune was predicted independently by John Couch Adams and Urbain Le Verrier by a process of mathematical investigation of discrepancies in the orbit of Uranus between $1843$ and $1846$.

It was first observed and recognised for what it was by Johann Gottfried Galle on $23$rd September $1846$, within a degree of where it was predicted to be.