When you look at the stars on a very clear night, keep your eye open for an unusual sight. These drifting stars are really satellites. A satellite is an object that revolves around a planet in a circular path. The moon is Earth's original, natural satellite, but there are many satellites created by scientists and engineers. Our satellites can take pictures of the earth, like weather satellites, or transmit signals from one place on Earth to another, like communications satellites.
Some satellites look out into space and record information about the galaxy.
Dozens of satellites cross the sky every night. They shine like stars because they reflect the light of the sun from the other side of the Earth.