Bob the Alien's Tour of the Solar System
Bob the Alien's Tour of the Solar System

Ten Facts about Neptune

Fact One

Neptune's moon, Triton, is slowly getting closer to Neptune. Eventually, it will get so close that it may get torn apart by Neptune's gravity and possibly form rings more spectacular than Saturn's.

Fact Two

The strongest winds in the Solar System have been recorded on Neptune, at speeds of up to 2,000 kilometres per hour.

Fact Three

Neptune has dark spots similar to the Great Red Spot on Jupiter. These are areas of high atmospheric pressure which force clouds of methane gas high up into the atmosphere, appearing like cirrus (thin, whispy) clouds on Earth. However, these spots disappear and reappear on different parts of the planet, unlike Jupiter's spot.

Fact Four

Neptune sometimes orbits the Sun further away than Pluto. From 1979 to 1999, Pluto was closer to the Sun than Neptune. As Pluto was classified as a planet at the time, Neptune was then the ninth planet from the Sun.

Fact Five

Triton orbits Neptune in the opposite direction to the planet's rotation. It is the only large moon in the Solar System to do this.

Fact Six

Neptune has four faint rings. Some parts of these rings are brighter in areas than others and appear like arcs orbiting the planet. Maybe they are still forming.

Fact Seven

Since its discovery in 1846, Neptune has completed only one full orbit of the Sun. In fact, it takes 165 years for the planet to go around the Sun.

Fact Eight

Neptune was discovered when scientists noticed something peculiar about Uranus' orbit, believing something to be pulling it in the opposite direction to the Sun's pull of gravity. They calculated the position of a planet and soon afterwards, discovered Neptune.

Fact Nine

The coldest temperatures measured in the Solar System (-230°c) have been recorded on Neptune's moon, Triton.

Fact Ten

Pluto, a dwarf planet which has an orbit which sometimes crosses Neptune's, may have been a moon of Neptune which escaped the planet's pull of gravity, but being prevented from escaping the Solar System by the gravitational pull of the Sun.

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Neptune Statistics Table

Meaning of NameRoman god of the Sea (Greek equivalent is Poseidon)
Name in Foreign LanguagesNeptune (French), Neptuno (Spanish, Portuguese), Neptun (German, Russian), Nettuno (Italian), Neptunus (Latin), Poseidon (Greek)
Average Distance from the Sun 4,498,252,900 km / 2,795,084,800 miles / 30.069 A.U.
Comparison with Earth: 149,597,890 km / 92,955,820 miles / 1.000 A.U.
Closest Distance to the Sun (Perihelion) 4,459,630,000 km / 2,771,087,000 miles / 29.811 A.U.
Comparison with Earth: 147,100,000 km / 91,400,000 miles / 0.983 A.U.
Farthest Distance from the Sun (Aphelion) 4,536,870,000 km / 2,819,080,000 miles / 30.327 A.U.
Comparison with Earth: 152,100,000 km / 94,500,000 miles / 1.017 A.U.
Diameter across equator49,528 km / 30,776 miles
Comparison with Earth: 12,756 km / 7,926 miles
Diagram showing planet's size compared to the size of Earth Sizes of Neptune and Earth compared
Circumference around equator 155,597 km / 96,683 miles
Comparison with Earth: 40,074 km / 24,901 miles
Mass102,440,000,000,000,000,000,000,000 kg
Comparison with Earth: 5,973,700,000,000,000,000,000,000 kg
Time to spin on Axis16 hours, 6.5 minutes
Comparison with Earth: 23 hours, 56 minutes
Time to orbit the Sun164.79 Earth years or 60,190 days
Comparison with Earth: 365 days, 6 hours
Distance planet travels to complete one orbit28,142,000,000 km / 17,487,000,000 miles
Comparison with Earth: 924,375,700 km / 574,380,400 miles
Gravity (Earth = 1)1.1
Escape Velocity85,356 km/h / 53,038 mph
Comparison with Earth: 40,248 km/h / 25,009 mph
Temperature at Cloud Tops-216 °c / -357 °F  / 57 K
Comparison with Earth's average temp: 15 °c / 59 °F / 288 K
Contents of AtmosphereHydrogen, Helium, Methane
Known moonsThere are at least 13 moons known to orbit Neptune - Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, Triton, Nereid, Halimede, Sao, Laomedeia, Psamathe, Neso
Past Missions (including nationality and year of launch) Voyager 2
Present Missions Voyager 2 (USA, 1977. Reached Neptune in 1989)
Proposed or planned MissionsThere are no proposed missions to Uranus

Bob the Alien's Tour of the Solar System
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