VenusPhases


General Description

This program illustrates the phases of Venus as predicted by either the Copernican system of the Ptolemaic system (the Copernican system is the default). One window shows Earth, the sun, and Venus on its Copernican orbit. Venus is shown as a disk with the side facing the sun colored yellow (since it reflects the sun's light) and the other side colored dark gray (since that side is dark). Playing the simulation puts all moving objects (ie Venus and Earth/Sun) in motion. Another window shows what Venus would look at this position, when viewed from Earth through a telescope. A menu option displays another window showing Galileo's drawings of his telescope observations of Venus.

All orbits are drawn to scale. However, the size of the planets/Sun are greatly exaggerated (they should all be essentially point-like on the scale shown) and even the relative sizes are not correct (Earth and Venus are MUCH smaller than Sun).


Orbit Frame


Telescope View Frame

Shows the view of Venus as seen from Earth when the Venus is in the position shown in the Orbit Frame. The phases of Venus are not apparent to the naked eye, but this view shows what we would see through a telescope if Copernicus' theory were correct.

Galileo's Drawings of Venus

Shows the sketches Galileo made while observing Venus through his telescope. These sketches can be compared to the output in the Telescope View Frame to determine whether or not Galileo's observation support the Copernican or Ptolemaic system.
Todd K. Timberlake (ttimberlake@berry.edu)