Neptune is the eighth planet from the Sun and the smallest of the gas giants. Neptune was the first planet found by mathematical prediction after unexpected changes in the orbit of Uranus were observed. Neptune is named after the Roman god of the sea.
Mass: 102,410,000,000,000,000 billion kg (17.15x Earth)
Equatorial Diameter: 49,528 km
Polar Diameter: 48,682 km
Equatorial Circumference: 155,600 km
Known Satellites: 14
Notable Satellites: Tritan
Orbit Distance: 4,498,396,441 km (30.10 AU)
Orbit Period: 60,190.03 Earth days (164.79 Earth years)
Surface Temperature: -201 °C
Discover Date: September 23rd 1846
Discovered By: Urbain Le Verrier & Johann Galle
Size of Neptune
Facts about Neptune Compared to the Earth
- Neptune has only been passed by one spacecraft, Voyager 2 which flew by on the 25th of August 1989.
- Although smaller in diameter than Uranus, Neptune has a greater mass.