Planets: Difference between revisions
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The term planet refers to a celestial body that orbits a [[star]] with a [[gravity]] in a specific range. The gravity of a planet must be strong enough to hold fluids and plastic solids in a stable state (hydrostatic equilibrium) which prevents them from escaping the planet and it makes the body round, and low enough to prevent stellar nuclear processes to start. | The term planet refers to a celestial body that orbits a [[star]] with a [[gravity]] in a specific range. The gravity of a planet must be strong enough to hold fluids and plastic solids in a stable state (hydrostatic equilibrium) which prevents them from escaping the planet and it makes the body round, and low enough to prevent stellar nuclear processes to start. | ||
Astronomical objects that meet the official criteria for planet status yet orbit a planet are instead classified as natural satellites or [[moons]]. When the [[barycentre]] of the planet-moon system falls outside the planet, then both bodies are considered planets and part of a double-planet system.<ref>[https://www.universetoday.com/85749/is-the-moon-a-planet/ Universe Today: Is The Moon A Planet?]</ref> | |||
Tidally locked planets is when the rotation period matches the host star. One hemisphere has perpetual daylight while the other has only night. | |||
==[[Terrestrial Planet]]s== | ==[[Terrestrial Planet]]s== | ||