The Earth’s Moon
Amazing Fact! Many scientists believe the moon formed when a small planet crashed into the Earth. Rock and dust were thrown into space. Gravity pulled the rock and dust together to form the moon.
In space, the force of gravity causes smaller objects to orbit larger objects. Any object that orbits another object is called a satellite. The Earth is a satellite of the Sun. The Earth’s moon orbits the Earth, so the moon is a satellite of the Earth. It takes the moon about 27.3 days to revolve once around the Earth. It also takes the moon about 27 days to rotate once on its axis. So, the side of the moon facing the Earth is always the same. On some nights, the moon appears in the sky as a bright circle. The moon appears bright because it reflects the light from the Sun. On other nights, the shape of the moon is different. The changing shape of the moon’s sunlit portion, as viewed from Earth, is called the phases of the moon.
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