This chart shows the differences between Neptune and Neptune. To change the planets/moons being compared, change one or more of the form fields at the bottom and click Refresh.

	Neptune	Neptune
Discovered By	Urbain Le Verrier, John Couch Adams, Johann Galle	Urbain Le Verrier, John Couch Adams, Johann Galle
Date of Discovery	23 September 1846	23 September 1846
Average Orbit Distance	4,498,396,441 km	4,498,396,441 km
Perihelion (closest)	4,459,753,056 km	4,459,753,056 km
Aphelion (farthest)	4,537,039,826 km	4,537,039,826 km
Equatorial Radius	24,622 km	24,622 km
Equatorial Circumference	154,704.6 km	154,704.6 km
Volume	62,525,703,987,421 km3	62,525,703,987,421 km3
Mass	102,410,000,000,000,000,000,000,000 kg	102,410,000,000,000,000,000,000,000 kg
Density	1.638 g/cm3	1.638 g/cm3
Surface Area	7,618,272,763 km2	7,618,272,763 km2
Equatorial Surface Gravity	11.15 m/s2	11.15 m/s2
Escape Velocity	84,816 km/h	84,816 km/h
Rotation Period (Length of Day)	0.671 sidereal days	0.671 sidereal days
Orbit Period (Length of Year)	164.79132 sidereal years	164.79132 sidereal years
Mean Orbit Velocity	19,566 km/h	19,566 km/h
Orbit Eccentricity	0.00859048	0.00859048
Orbit Inclination to Ecliptic	1.77 degrees	1.77 degrees
Equatorial Inclination to Orbit	28.3 degrees	28.3 degrees
Orbit Circumference	28,263,736,967 km	28,263,736,967 km
Effective Temperature	-214 °C	-214 °C
Atmospheric Constituents	Hydrogen, Helium, Methane	Hydrogen, Helium, Methane