LASP pre-dates NASA as a leader in space exploration.
The Orbit Simulator shows the orbits of the planets around the Sun.
This simulation shows the motion of the planets and other objects around the Sun. You can see the:
You can also create a planet with a given eccentricity and distance to see what happens to it.
A graph section of the simulation (hidden at the lower right of the window) shows the relationship between different parameters, for example period and distance.
How planets formed from the disk of material around the Sun.