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ORIGIN OF THE SOLAR SYSTEMiStock-910174036 - Coggle Diagram

- - - - proposed by Nicolas Copernicus
    - - In 1514, copies began circulating within his fellow astronomer and scholar friends. This 40-page manuscript described his ideas about the heliocentric hypothesis.
      - He based it in seven principles.
        
         The distance between Earth and the sun is an insignificant fraction of the
        distance from Earth and Sun to the stars, so parallax is not observed in the stars.
        
        The stars are immovable – their apparent daily motion is caused by the daily
        rotation of Earth.
        
        The center of Earth is the center of the lunar sphere—the orbit of the moon
        around Earth.
        
        Earth's orbital motion around the sun causes the seeming reverse in direction of the motions of the planets
        
        All the spheres rotate around the sun, which is near the center of the universe
        
        Earth is moved in a sphere around the sun, causing the apparent annual
        migration of the sun. Earth has more than one motion.
        
        Celestial bodies do not all revolve around a single point.
  - - - proposed by Claudius Ptolemy
    - - The sun, moon, stars, and five planets (Mercury, Venus, Mars, Jupiter, Saturn) moved around earth.
      - Planets move with respect to a fixed star, with changing brightness, changing speed, and having retrograde motion.
      - Ancient Greeks believed that the universe was perfect and infinite.
- - - - It was proposed by James Jeans and
        Harold Jeffreys in 1918.
        
        The angular momentum problem is
        not fully explained.
        
        Serious objections against the encounter
        theories remain.
      - It is a
        variation of the planetesimal concept.
        
        As the stream of gaseous material
        condensed, it separated into masses of
        various sizes, which, by further
        condensation, took the form of the planets
        
        It suggests that a huge tidal wave, raised
        on the sun by a passing star was drawn
        into a long filament and became detached from the
        principal mass.
    - - Encounter or collision theories, in which a star passes close by or actually collides with the sun, try to explain the distribution of angular momentum.
    - - Some
        of this erupted matter was torn free.
      - The smaller masses quickly cooled to
        become solid bodies, called
        planetesimals.
        
        As their orbits crossed, the larger bodies
        grew by absorbing the planetesimals, thus
        becoming planets.
  - - - It is generally acceptable to most
        scientists because it explains many of the
        known facts about the solar system.
        
        This idea has replaced the original nebular
        hypothesis of Kant and Laplace. It also replaced the later planetesimal
        hypothesis
      - It is nonetheless far from complete , and
        the origin of the solar system and Earth is
        still largely in the realm of speculation.
    - - Each of these great whirlpools might then
        have collected the surrounding material by
        gravitational attraction, thus forming a protoplanet.
        
        It is believed that nine protoplanets –one
        for each of the present-day planets—were
        formed and these were originally much
        larger than the finished planet.
        
        Many astronomers support this theory
        because observations through large
        telescopes have revealed numerous true
        nebulas between the stars.
        
        Some of these massive swirls of gas and
        dust are actually condensing to form new
        stars.
        
        Smaller whirlpools developed inside some
        of the larger vortexes.
        
        These gave rise to spinning discs that
        became the satellites, or moons, of the
        planets.
  - - - These clouds are gravitationally unstable, and
        matter coalesces within them to smaller
        denser clumps, which then rotate, collapse,
        and form stars.
    - - This may give birth to planets in certain
        circumstances, which are not well known.
      - Theformation of planetary systems is thought to be a natural result of star formation.
    - - As a result, they are several times more
        massive than in the inner part of the
        protoplanetary disk.What follows after the embryo formation is not
        completely clear.