Planetary Motion

This applet shows clearly the use of Java threads to achieve animation.
The rotating bodies follow Kepler's Law, rotating in eliptical orbits around the earth. The bird "chirps" when it get close to the earth! The flying saucer makes intermittent appearances.
The speeds of rotation depend on the speed of the processor within which the applet is viewed, making it difficult to produce a pleasing display within all browsers when the applet is initiated.
This Java applet was created originally using Sun Java jdk 1.2.2. on a 366MHz processor; it was recently optimised for a 850MHz processor - using j2sdk1.4.0 - by adjusting the step rates of the rotating bodies, the chirping behaviour of the bird and the repaint( ) rate of the applet screen. Buttons to accelerate and decelerate rotational speeds were also added.

Browsers:

  • - Microsoft Explorer 5.0 - 6.0 (recommended).
  • - Netscape Communicator 4.73.

[UML Diagram]

Implemented by
John R. Oliver
 Tel: +44 1494-488-409
E-Mail: john.r.oliver@btinternet.com
Java Class files updated
wef 28 Apr 2003.
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