Skip to main content Skip to Search Box
Definition: planet from Astronomy Encyclopedia

Large, non-stellar body orbiting the Sun or another star and shining only by reflected light. Planets may be either rocky in composition, such as Mercury, Venus, Earth and Mars, or mainly gaseous, such as Jupiter, Saturn, Uranus and Neptune. Nine major planets exist in our Solar System, together with thousands of minor planets or asteroids. The name is Greek in origin, meaning ‘wandering star’. See also PLANET X

planet

From The Columbia Encyclopedia
[Gr.,=wanderer], a large nonluminous body of rock or gas that orbits the sun or another star, has a rounded shape due to gravity, and has cleared its orbit of smaller objects. The term, once limited to any of the eight solid, nonluminous bodies (also called major planets) that revolve around the sun, has been extended to include similar bodies discovered revolving around other stars. The term planet sometimes has been used to include dwarf planets and asteroids (or minor planets); it does not include comets and meteoroids (see meteor . See also planetary science and planetary system , as well as the table entitled Major Planets of the Solar System . The major planets are classified either as inferior, with an orbit between the sun and the orbit of Earth ( Mercury and Venus ), or as superior, with an orbit beyond that of Earth ( Mars , Jupiter , Saturn , and Uranus , Neptune . Pluto , long regarded after its discovery in 1930 as the ninth planet, was gradually recognized as a Kuiper…
12,006 results

Full text Article planet

From The Columbia Encyclopedia
[Gr.,=wanderer], a large nonluminous body of rock or gas that orbits the sun or another star, has a rounded shape due to gravity, and has cleared its orbit of smaller objects. The term, once limited to any of the eight solid, nonluminous bodies (also called major planets) that revolve around the…
| 1,336 words
Key concepts:

Full text Article PLANET

From Gaither's Dictionary of Scientific Quotations
American writer At night I lie awake In the ruthless Unspoken knowing that planets come to life, bloom, and die away like day-lilies opening one after another in every nook and cranny of the Universe… The Planets: A Cosmic Pastoral (p. 138 ) William Morrow and Co. New York New York USA…
| 4,025 words
Key concepts:

Full text Article planet

From The Chambers Dictionary
any of the large celestial bodies that revolve about the sun reflecting the sun's light and generating no heat or light of their own, these being Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune; a satellite of a planet ( secondary planet ); an astrological influence vaguely…
| 308 words
Key concepts:

Full text Article planet

From Britannica Concise Encyclopedia
Any large natural body that orbits the Sun or another star ( see planets of other stars ) and that is not radiating energy from internal nuclear fusion; dwarf planet s, comet s, asteroid s, meteoroids ( see meteor ), and natural satellite s are excluded. The word planet comes from the Greek for…
| 318 words
Key concepts:

Full text Article planet

From The American Heritage(R) Dictionary of the English Language
a. In the traditional model of solar systems, a celestial body larger than an asteroid or comet, illuminated by light from a star, such as the sun, around which it revolves. b. A celestial body that orbits the sun, has sufficient mass to assume nearly a round shape, clears out dust and debris from…
| 501 words
Key concepts:

Full text Article planet

From The Hutchinson Unabridged Encyclopedia with Atlas and Weather Guide
Celestial body that is in orbit around a star, is large enough to be spherical, and which dominates its orbit (sweeping its neighbourhood clear). There are eight planets in the Solar System orbiting the Sun : Mercury, Venus, Earth, Mars, Jupiter, Saturn, Neptune and Uranus. The inner four, called…
| 646 words
Key concepts:

Full text Article planet

From Collins Dictionary of Astronomy
Any of a class of rotating oblate spheroid bodies of substantial size that orbit the Sun or other stars and shine only by the light reflected from their primaries. In the Solar System there are nine known planets, varying in diameter from a little over 2000 km for Pluto to about 140 000 km for…
| 457 words
Key concepts:

Full text Article planet

From The American Heritage Student Science Dictionary
A large, nearly spherical celestial object that orbits a star, does not produce its own light, is not a satellite of another planet, and is massive enough to clear away neighboring objects from its orbit. In our solar system there are eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, …
| 273 words
Key concepts:

Full text Article Planet

From A Dictionary of Literary Symbols
A planet is a “wandering star” (Greek aster planetes ). In the pre-Copernican view of the cosmos, established mainly by Aristotle and Ptolemy, there are seven of them, seven heavenly bodies that seem to move against the backdrop of the fixed stars. According to their distance from the earth, the…
| 574 words
Key concepts:

Full text Article planet

From The Macquarie Dictionary
a. Astronomy a celestial body revolving around the sun and visible by its reflected light, large enough to exert sufficient gravity on itself to achieve a rounded shape, and to clear its orbit of all asteroids, comets, and other space debris. Around the sun (in the solar system) there are eight…
| 223 words
Key concepts:
Mind Map

Stack overflow
More Library Resources