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Astronomy
 
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Planets and dwarf planets of the solar system

Definition of planet: “A planet is a celestial body that is in orbit around the Sun, which has sufficient mass for its gravity to overcome the cohesive forces of the solid body and maintain it in hydrostatic equilibrium (spherical shape) , and which eliminated any body moving in a close orbit. This definition was approved on August 24, 2006, during the 26th General Assembly of the IAU by a show of hands of 400 scientists after ten days of discussions.
If we could look at the Solar System from the outside, far above the Earth's north pole, we would see the planets rotating around the Sun, counterclockwise. We would see that the rotation disk of the planets is remarkably flat, only Mercury has an orbit inclined relative to the others (7°). But we wouldn't notice the planets rotating on their axis. Each planet revolves around a different axis of rotation.

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