What is the natural satellite of the earth?

A satellite is a celestial body that periodically orbits the planet in a closed orbit. But if two celestial bodies are of equal mass, the system they form is generally called a two-planet system, not a planet and a natural satellite. Usually, the center of mass of two celestial bodies is within the planet. Therefore, some astronomers believe that Pluto and Pluto should be classified as twin planets, but the discovery of two new Pluto satellites in 2005 made the problem more complicated. A natural satellite refers to a natural celestial body orbiting a planet. The moon is the most obvious example of a natural satellite. In the solar system, all planets except Mercury and Venus have natural satellites. There are at least 40 known natural satellites in the solar system (not counting the debris that makes up the planetary ring). Natural satellites are planets orbiting planets and planets orbiting stars. For example, in the solar system, the sun is a star, and planets such as our earth revolve around the sun, while planets such as the moon, Enceladus and Tianwei revolve around our earth. These planets are called natural satellites of planets. Saturn has the largest number of natural satellites, of which 17 has been confirmed, and at least 5 have yet to be confirmed. Natural satellites vary in size and are very different from each other. Some of them are only a few kilometers in diameter, such as two small satellites on Mars and some small satellites outside Jupiter.