Universe Today
The following Neptune fact sheet is based on NASA's excellent planetary fact sheets. Neptune is the 8th planet from the Sun, and it requires a telescope to be able to see it.
Mass: 102.43 x 1024 kg Volume: 6,254 x 1010 km3 Average radius: 24,622 km Average diameter: 49,244 km Mean density: 1.638 g/cm3 Escape velocity: 23.5 km/s Surface gravity: 11.15 m/s2 Natural satellites: 13 Rings? - Yes Semimajor axis: 4,495,060,000 km Orbit period: 60,189 days Perihelion: 4,444,450,000 km Aphelion: 4,545,670,000 km Mean orbital velocity: 5.43 km/s Orbit inclination: 1.769° Orbit eccentricity: 0.0113 Sidereal rotation period: 16.11 hours Length of day: 16.11 hours Axial tilt: 28.32° Discovery: 23 September 1846 Minimum distance from Earth: 4,305,900,000 km Maximum distance from Earth: 4,687,300,000 km Maximum apparent diameter from Earth: 2.4 arc seconds Minimum apparent diameter from Earth: 2.2 arc seconds Maximum visual magnitude: 7.78
We've written many articles about Neptune for Universe Today. Here's an article about the color of Neptune, and here's an article about the atmosphere of Neptune.
If you'd like more info on Neptune, check out Hubblesite's News Releases about Neptune, and here's a link to NASA's Solar System Exploration Guide to Neptune.
We've also recorded an entire episode of Astronomy Cast just about Neptune. Listen here, Episode 63: Neptune.
