A planet is a round object that moves around a star in a fixed orbit. Our solar system has eight planets that revolve around their star called the sun. The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

An orbit is a regular or repeating path that an object in space takes around another one. All planets move around the sun in their own orbits. The moon revolves around the earth in its own orbit.

An object that moves around a planet in a fixed path is called a satellite. The earth has one natural satellite, the moon . Artificial satellites are sent by humans for communication, mapping and scientific studies.