Solar Planets Science Projects

The 2006 International Astronomical Union (IAU) defines a planet as a body in orbit around the Sun that was large enough to have achieved hydrostatic equilibrium and to have “cleared the neighbourhood around its orbit”. The practical meaning of “cleared the neighborhood” is that a planet is comparatively massive enough for its gravitation to control the orbits of all objects in its vicinity. By the IAU’s definition, there are eight planets in the Solar System; four terrestrial planets (Mercury, Venus, Earth and Mars) and four giant planets, which can be divided further into two gas giants (Jupiter and Saturn) and two ice giants (Uranus and Neptune). When excluding the Sun, the four giant planets account for more than 99% of the mass of the Solar System.

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