Planet - Wikipedia
网页A planet is a large, rounded astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. [1]
About the Planets - Science@NASA
网页The solar system has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. There are five officially recognized dwarf planets in our solar system: Ceres, Pluto, Haumea, Makemake, and Eris. 8.
What is a Planet? - Science@NASA
网页A planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit.
Planet | Definition, Characteristics, & Facts | Britannica
网页2024年9月17日 · Planet, broadly, any relatively large natural body that revolves in an orbit around the Sun or around some other star and that is not radiating energy from internal nuclear fusion reactions. There are eight planets orbiting the Sun in the solar system.
What Is a Planet? | NASA Space Place – NASA Science for Kids
网页2019年6月27日 · What Is a Planet? The Short Answer: A planet must do three things: it must orbit a star, it must be big enough to have enough gravity to force a spherical shape, and it must be big enough that its gravity cleared away any objects of a …
Planets 101: What they are and how they form | Astronomy.com
网页2023年10月18日 · What is a planet? Mars, the fourth planet from the sun. Credit: NASA / JPL. According to a definition issued by the International Astronomical Union (IAU) in 2006, a planet is a celestial...
The Nine Planets of The Solar System | Eight Planets Without ...
网页An overview of the history, mythology and current scientific knowledge of the planets, moons and other objects in our solar system.
Solar System 101 | National Geographic - YouTube
网页How many planets are in the solar system? How did it form in the Milky Way galaxy? Learn facts about the solar system’s genesis, plus its planets, moons, and...
Planet Facts – The Planets In Order
网页Our solar system has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. With the exception of Uranus and Neptune, each of these planets can be seen unaided. All eight planets can be see through the use …
What is a Planet? | Planets – NASA Solar System Exploration
网页A planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.