Phases of the Moon
- Brad Ballinger
What this shows
This model (not to scale) represents how the moon appears to us from Earth. The Earth (as seen from space, above the north pole) is at the center of this model. Its light blue left half indicates that the Sun is placed far off the left side of the screen. The moon (as seen from above north pole) is the next object away from the center. The light gray half points toward the sun, because that side is illuminated. The red semicircle shows the half of the moon that isn't visible from Earth (because it points away from us). The last object is how the moon looks from Earth according to the model. This model explains some things, but not all: for example, the north pole is only rarely on a great circle between day and night.
What to do
Move the Moon by dragging the white point at its center. It moves counter-clockwise in nature. Note: This was made with a north pole bias. To represent the progression of moon phases as seen from the southern hemisphere, move the moon clockwise instead.