MoonPhases


General Description

This program illustrates how the appearance of Moon changes depending on the position of Moon relative to Earth and Sun. The left window shows Earth (at the center) and Moon, as well as a circle tracing out Moon's orbit. Sun is far to the right in this picture and therefore the right side of Earth and Moon are bright while the left sides are dark. A glowing band of light shows the portion of Moon visible from Earth, as well as the portion of Earth from which Moon is visible. The angle between Sun and Moon (as seen from Earth) can be adjusted. A green dot indicates an observer on Earth and the observer's local (mean solar) time can be set, which effectively changes the observer's location on Earth in this picture.

The right window shows the appearance of Moon as seen from Earth when Moon is in the position shown in the left window. Note that the darkness of the dark part of Moon changes depending on the loction of Moon in its orbit. This is because Moon receives reflected light from Earth, a phenomenon known as Earthlight, and the amount of reflected light received is connected to the location of Moon in its orbit.


Visual Elements


Control Frame


Todd K. Timberlake (ttimberlake@berry.edu)