A large spherical astronomical object that typically [[in orbit| orbit]]s a [[star (sky)|]]. The tag should be used when at least one planet is seen from outer [[space]] or from the surface of another nearby planet. This includes real and fictional planets.  

Scientifically, there has always been some ambiguity as to what constitutes a planet, with some celestial bodies such as [[Pluto (planet)|]] and Ceres being considered at different times or by different people either as planets or as "dwarf planets". The International Astronomical Union (IAU) came up with a definition for a planet in 2006, meaning that the planets in our solar system are officially [[Mercury_(planet)|]], [[Venus (planet)|]], [[Earth (planet)|]], [[Mars_(planet)|]], [[Jupiter (planet)|]], [[Saturn (planet)|]], [[Uranus (planet)|]] and [[neptune (planet)|]], but the definition remains contentious.

h4. Planets

* [[Mercury (planet)|]]
* [[Venus (planet)|]]
* [[Earth (planet)|]]
* [[Mars (planet)|]]
* [[Jupiter (planet)|]]
* [[Saturn (planet)|]]
* [[Uranus (planet)|]]
* [[Neptune (planet)|]]
* [[Pluto (planet)|]]

h4. Fictional planets

* [[Coruscant]]
* [[Cybertron]]
* [[Planet Glorie]]
* [[Takodana]]

h4. See also
* [[atmospheric layer]]
* [[moon]]
* [[sun]]
* [[star (sky)]]
* [[space]]

h4. External links

* "Wikipedia: Planet":https://en.wikipedia.org/wiki/Planet
* "Wikipedia: Solar system":https://en.wikipedia.org/wiki/Solar_System
惑星