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Orrery

Last updated: 08.05.2002

Orrery

An applet to display a simple orrery, a working model of the Solar System.

An orrery (named for Charles Boyle, 4th Earl of Orrery), is a simple mechanical working model of the planets of the Solar System. This Java applet implements an orrery in software.

This implementation should not be taken as being mathematically or astronomically correct. Nevertheless, it gives a rough idea of the positions, rates of rotation, and relative sizes of the planets (note that the planets are enormously scaled-up: if they were shown at their correct size in proportion to their orbit, even Jupiter would be an invisibly small dot).

The orrery has various options, which are controlled by the strip of buttons at the base of the applet. You can use the 'Zoom' control to zoom in and out on the model in order to see the inner and outer planets. The 'Speed' control allows you to speed up or slow down the display. The 'Names' button switches the display of planet names on and off, while the 'Style' button steps through six different display styles. According to the style selected, planets may be shown at fixed sizes, or scaled in proportion to each other, and they may be shown as simple white circles or as colored icons simulating the 'real' appearance of the planet in question. They may also be shadowed according to their position relative to the sun (the shadowing is not strictly realistic, but adds to the appeal of the display).

Documentation and Sources

Note: because of bugs in the Java implementation in some recent versions of Explorer, this applet may not display correctly on this page. Try viewing it through the applet tester instead. Note also that as it is a Java 1.1 applet, it will not run at all on some Netscape browsers, which only implement Java 1.0. See the note on compatibility.