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Planets & galaxies

  1. May 13, 2012 #1
    why do planets move around stars in the same level ?
    why do stars move around black holes in the same level?
    why dont some of them move in horozintal level & the others in vertical level?
  2. jcsd
  3. May 13, 2012 #2


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    The short version is that they don't move around in the same level.

    Stars and planets both have varying inclinations in their orbits and can even orbit "up and down". (Although there really isn't an up and down in space unless we define two directions to be so)

    For example, the orbital tilt of Pluto is 17 degrees off from the "normal" plane that the rest of the planets are in. But even the other planets have slight tilts as well.

    As for black holes, we have observed stars orbiting the supermassive black hole at the center of our galaxy in all sorts of directions.
  4. May 14, 2012 #3
    Conservation of angular momentum of material that collapsed under gravitational attraction results in Circumstellar disk.
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