The yellow disk is a sun in a solor system. The light blue disk is a planet and the green disk is a moon. The short pink lines starting at the each disks are the velocitys. The sun, the planet and the moon attract each other by universal gravitation.
First, click the start button. These disks start moving. If you drag the pointer near each disk, you can change the velocity and the position.
Next, click the Strobo button. You can see the orbit line of each disks. The orbit lines can erase by clicking Start button. If you click the Reset button, you can set the situation initial.
This simulation is calculated by 4th order Runge-Kutta method.
You can get the source code of the solar system here.
Copyright 1997 KATO Noriyoshi
Nori's personal computer physics