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Solar System showing the planets orbiting our sun. The simulation begins with all of the planets lined up at their maximum distances from the sun (aphelion). As they are released, so they are attracted to the sun and describe their various orbits. This arrangement allows you to compare their distances and orbits in a simple way. In reality, the planets are not aligned in this way and their orbits are at angles to each other. The planets are shown at their correct relative sizes (i.e. compared to each other) and their correct relative distances. Their relative years (orbital periods) are also about right. The sun is shrunk down compared to the planets so that it doesn't swallow the innermost planets. In reality, the planets (and even the sun) are very tiny compared with the orbital distances.

Notice how the further the planets are from the sun the slower they move. Compare the sedate progress of Neptune (with an orbital period of about 165 years) to the frenzied circling of Mercury (whose year lasts less than a quarter of our Earth year). If you look carefully, you can see that Mercury speeds up as it gets closer to the sun (bottom left of graphic) see the animation of Mercury orbit. Once the movie has fully appeared you can move the slider back and forth to see these effects at different speeds.

The outer four planets are all gas giants. From the sun, the planets are:

  • Mercury
  • Venus
  • Earth
  • Mars
  • Jupiter
  • Saturn
  • Uranus
  • Neptune
created using the brilliant Cheetah3D software.



Poster of types of optical telescope: Newtonian, Refracting, and Casserian.
Telescopes Poster

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PO Box 9150, Deakin, ACT 2600, Australia. Mobile phone Australia 0405 17 64 71
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