Apart from Venus and Mars, the Solar System planets generate magnetic fields, and all the major planets except Venus and Mercury have natural satellites. All the major planets of the Solar System other than Mercury possess a considerable atmosphere, and some share such features as ice caps, seasons, volcanism, hurricanes, tectonics, and even hydrology.

(When the term 'planet' is applied more broadly, these eight uncontroversial planets can be distinguished by calling them 'major planets'.) These planets each rotate around an axis tilted with respect to its orbital pole. The Solar System has at least eight planets: the terrestrial planets Mercury, Venus, Earth, and Mars, and the giant planets Jupiter, Saturn, Uranus, and Neptune. Planets grow in this disk by the gradual accumulation of material driven by gravity, a process called accretion. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a young protostar orbited by a protoplanetary disk. The eight planets of the Solar System with size to scale (up to down, left to right): Saturn, Jupiter, Uranus, Neptune (outer planets), Earth, Venus, Mars, and Mercury (inner planets)Īccording to NASA, in order to become classified as a Planet, first, it has to be in orbit with a star or have previously, second, it must have enough mass to sustain it's roundness, finally, it must have sufficiently strong gravity, that it has cleared away any other heavenly bodies of a similar volume near its orbit around a star.

For other uses, see Planet (disambiguation). This article is about the astronomical object.

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