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Neptune: Overview
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Voyager 2 captured this image of Neptune in 1989.
Voyager 2 captured this image of Neptune in 1989.

10 Need-to-Know Things About Neptune:

  1. If the sun were as tall as a typical front door, the Earth would be the size of a nickel and Neptune would be about as big as a baseball.
    Color image of clouds on Neptune.
    Vertical relief in Neptune's bright cloud streaks.
  2. Neptune orbits our sun, a star. Neptune is the eighth planet from the sun at a distance of about 4.5 billion km (2.8 billion miles) or 30.07 AU.
  3. One day on Neptune takes about 16 hours (the time it takes for Neptune to rotate or spin once). Neptune makes a complete orbit around the sun (a year in Neptunian time) in about 165 Earth years (60,190 Earth days).
  4. Neptune is a sister ice giant to Uranus. Neptune is mostly made of a very thick, very hot combination of water (H2O), ammonia (NH3), and methane (CH4) over a possible heavier, approximately Earth-sized, solid core.
  5. Neptune's atmosphere is made up mostly of hydrogen (H2), helium (He) and methane (CH4).
  6. Neptune has 13 confirmed moons (and 1 more awaiting official confirmation of discovery). Neptune's moons are named after various sea gods and nymphs in Greek mythology.
  7. Neptune has six rings.
  8. Voyager 2 is the only spacecraft to have visited Neptune.
  9. Neptune cannot support life as we know it.
  10. At times during the course of Neptune's orbit, dwarf planet Pluto is actually closer to the sun, and us, than Neptune. This is due to the unusual elliptical (egg) shape of Pluto's orbit.

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Homework? We can help. Link to Neptune homework helper.
Just the Facts
Orbit Size (semi-major axis):  4,498,396,441 km
Mean Radius:  24,622 km
Volume:  62,525,703,987,421 km3
Mass:  102,410,000,000,000,000,000,000,000 kg
Resources
Visit Neptune
Visit Neptune
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"I really enjoy my involvement in space missions -- it is the best part of my job -- Voyager, Galileo, Deep Space 1, New Horizons and Juno." Read More...
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Last Updated: 2 Apr 2014