# What Are the Planets in Order From Shortest Period of Revolution to Longest?

By J. Eric Loberg

Kepler is a German and he comes a little bit before Galileo. Find out about the planets in order from shortest to longest period of revolution with help from the manager, lecturer and program planner at the Taylor Planetarium at the World renown Museum of the Rockies in this free video clip.

### Transcript

My name is Eric Loberg, the director here at The Taylor Planetarium at The Museum of The Rockies. I was going to talk bout the order of planets from their revolution around the sun in order of smallest to longest and this is kind of an easy list I suppose because the order of revolution around the sun is something that Kepler comes up with. Kepler is a German and he comes a little bit before Galileo. He starts to look at the precise motion of planets around the sun and he comes up with three planetary motion laws which talk about how planets aren't in exact circles. They are in ellipses which is, this is exaggerated, it's a little long but they are not quite circular and that the planets are going around two points in this ellipse. It also talks about how fast those planets are going around and this third law basically boils down to saying that the planets will go around their objects in the order of fastest to slowest if they are nearer to that object. So the planets in order of their revolution around the sun in their order, kind of a simple list, it's Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune and that's just simply the farther out from the sun, the slower they orbit around the sun and that's their revolution. Perhaps we could talk about their rotation instead because this list is slightly different. The rotation of the big planets is faster than those of the small planets and that's because when the big planets form, they shrink down, all the matter starts to clump together and they spin even faster. And so the big planets are the ones that are spinning the fastest. So the order of rotation, the days of a planet would look a little more like this. So the planets in order of their rotation which is their daily speed instead of their revolution would be Jupiter first, the largest planet, then Saturn, Neptune, Uranus, Earth, Mars, Mercury and then Venus. I'm Eric Loberg with The Museum of the Rockies, Taylor Planetarium.