Over 60 years after Uranus was discovered, scientists discovered Neptune. Over 70 years after the discovery of Neptune, it was noted that a body farther out was pulling on Neptune. That led to the discovery of Pluto in 1930.
            Period of revolution: 164.8 years. Period of rotation: 22 hours. Main components of atmosphere: Hydrogen, helium, methane. Known moons: 8.
Temperatures: Day -173°C; Night (?).