Video: 'Top 10 AMAZING Facts About Neptune'

(Thursday, September 24, 1846, 12:15 a.m. local time) — Neptune, the eighth and farthest known planet from the Sun in the Solar System, was identified as a planet early this morning at the Berlin Observatory by German astronomer Johann Gottfried Galle.

It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet.

It is 17 times the mass of Earth.