Eclipse and Moon Phase Simulation

This real-time 3D simulation allows students to control and interact with solar eclipses, lunar eclipses, and the different phases of the moon. The moon revolves around Earth in an elliptical orbit. It takes the moon about 27.3 days to orbit Earth once. This interactive 3D simulation demonstrates how this orbit causes the phases of the moon and eclipses.

Eclipses depend on the moon's revolution around Earth. The moon's orbit is tilted with respect to Earth's orbit, so the moon rarely goes directly between Earth and the Sun or directly behind Earth. When the moon does move into one of these positions, an eclipse occurs. The simulation allows the student to control the position of the Earth, Sun and moon while viewing the scene from a number of different angles and perspectives to fully understand the concepts being taught.

A solar eclipse occurs when the new moon passes between Earth and the sun, blocking the sunlight from reaching Earth. The darkest part of the moon's shadow, the umbra, is cone-shaped. Where this shadow reaches Earth, people viewing the sun see a total solar eclipse.

A lunar eclipse occurs at a full moon when Earth is directly between the moon and the sun, blocking sunlight from reaching the moon. The darkest part of Earth's shadow, the umbra, is cone-shaped. When the moon is within Earth's umbra, you see a total lunar eclipse.

The different shapes of the sunlit moon you see from Earth are called phases. Phases are caused by changes in the relative positions of the moon, Earth, and the sun. Because the sun lights the moon, half the moon is almost always in sunlight. As the moon revolves around Earth, the phase of the moon you see depends on how much of the sunlit side of the moon faces Earth.