Gravity and Motion The strength of the force of gravity between two objects depends on two factors: the mass of the objects and the distance between them. If mass increases, force also increases. If distance increases, force decreases. Two factors --inertia and gravity-- combine to keep Earth in orbit around the sun and the moon in orbit around Earth.

Lunar Basics The moon moves through space in two ways- revolving around Earth and rotating on its own axis. The moon does not produce light Sunlight reflects off the moon and that reflection is what makes the moon glow. Moon phase we see depends on how much of the sunlit side of the moon faces Earth.

Lunar Basics The Moon is in a synchronized rotation with Earth so the same side is always facing us. The rise and fall of the tides on Earth is caused by the Moon The Moon has quakes caused by the gravitational pull of the Earth. The moon goes through 8 phases- can you name them?