home | sky notes | astro 101 | facebook | store


8th planet from the Sun, the fourth largest planet in the solar system
Average distance from the Sun     4,504,000,000 km / 30.06 AU
Diameter     49,532 km (equatorial)
Mass     1.0247e26 kg
Orbital period around the Sun     164.8 Earth years / 60,150 Earth days
Number of moons     about 13 moons
Neptune is smaller in diameter than Uranus, but larger in mass. It is the first planet found from calculations based on the observed positions of the other planets. Because Pluto's orbit is so eccentric, it crosses the orbit of Neptune, making Neptune the most distant planet from the Sun for a few years. Like Uranus, it is difficult for beginners with small telescopes to find it. Neptune usually appears simply as a bluish-green star. In slightly larger scopes it will look more like a disk and less like a point of light. Neptune has at least 13 moons. The biggest is named Triton.

Our Solar System

Our solar system is located on the edge of a spiral arm called Orion’s Arm, and is one-half to two-thirds of the way (28,000 light-years) from the center of our Milky Way galaxy.

The Sun, Sol

The Inner Planets
    The Moon

The Asteroid Belt
  Dwarf planet, Ceres
  Asteroid, Ida
  Asteroid, Vesta
  Asteroid, Eros

The Outer Planets

The Kuiper Belt
  Dwarf planet, Pluto
  Dwarf planet, Eris

The Oort Cloud
  Dwarf planet, Sedna
  Comet Halley
  Comet Hale-Bopp

  Glossary of Terms
Copyright © 1999- The Astrogirl Homepage. All Rights Reserved.
Sun Mercury Venus Earth Moon Mars Ceres Ida Eros Vesta Jupiter Saturn Uranus Neptune Pluto Eris Sedna