The yellow disk is a sun in a solor system and the light blue disk is a planet. The short pink line starting at the planet is the velocity of the planet. The sun and the planet attract each other by universal gravitation.
First, click the start button. The planet starts moving around the sun. If you drag the pointer near the planet, you can change the velocity and the position of the planet.
Next, click the Strobo button. You can see the orbit line of the planet. The orbit line can erase by clicking Start button. If you click the Reset button, you can set the state of planet initial.

This motion is calculated by 4th order Runge-Kutta method.

Copyright 1997 KATO Noriyoshi

▲NoriMari homepage
▲Nori's personal computer physics
▲Nori's Java