Planets

A planet is defined as a sphere of non-plasma matter that can revolve around a star, but does not have to. However, 99.9% of planets orbit stars.

The Eight Planets of the Solar System
The eight most well-known planets lie in our Solar System. They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. In addition to the eight major planets, there are also some minor, or "dwarf", planets. These include the long-thought-to-be-a-planet Pluto, Eris, Haumea, Makemake, and Ceres.

Exoplanets
However, many other exoplanets have been found. An exoplanet is a planet that does not orbit the Sun, but may orbit a different star. The nearest exoplanet is Proxima Centuari b, a planet that orbits the star Proxima Centuari, which is 4.23 light-years away from the Sun.