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What is solar system


What is solar system

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									                    What is solar system
    A solar system is defined as the collection of planets and other
    heavenly bodies — such as asteroids, comets, and meteors — that
    orbit a central star. Most of the time when we speak of a solar
    system, we are speaking of the one of which Earth is a part: the
    group of planets and other heavenly bodies that orbit the star we call
    the Sun.
    In our solar system, the heavenly bodies that surround the sun and
    are held by its gravityinclude dwarf planets and natural satellites, as
    well as asteroids, comets, and meteors. It is now considered that
    there are eight planets, which in order from the sun outwards are
    Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
    Though considered a planet for many years, Pluto was reclassified in
    2006, and is now called a dwarf planet.
    Planets are now defined by the International Astronomical Union by
    several criteria. To be considered a planet, a heavenly body must:
         not be a star
         orbit a star
         have sufficient mass to be nearly spherical
         have cleared its orbit of other objects

    The planets in our solar system have much in common: they all rotate
    on their axis as they revolve around the sun in the same direction.
    Nevertheless, the planets in our solar system have different physical
    properties, and based on these properties and their arrangement in
    space, they are commonly grouped into the inner planets and the
    Jovian planets. Jove is an alternative name for the god Jupiter.

    The inner planets of our solar system — those nearest the sun—are
    Mercury, Venus, Mars, and Earth. These planets are smaller and
    denser, with solid crusts and molten interiors. Three of the four — all
    except Mercury — have a gaseous atmosphere. The Jovian planets
    are larger and less dense, with thick atmospheres.
The sun’s gravitational pull is responsible for the elliptical orbits of the
planets in our solar system. Johannes Kepler first described planetary
motion accurately in the early 1600’s. It was Isaac Newton who
demonstrated that Kepler’s laws of planetary motion applied to other
heavenly bodies in the solar system and were the result of the sun’s
gravitational force.

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