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Can I be correct to say

  1. Oct 20, 2007 #1
    that if all electrons orbit atoms,
    and atoms in the form of moons orbit planets,
    and planets orbit stars,
    and stars orbit the black hole in the centre of their galaxy,
    will all galaxies orbit around a single greater, or greatest mass?
  2. jcsd
  3. Oct 20, 2007 #2
    Some galaxies are part of a "cluster" of many galaxies. These in turn orbit a common center.

    This is not a requirement. Many galaxies are drifting through intergalactic space, orbiting nothing.

    There is no "center" to the universe, and certainly no requirement that all galaxies shall orbit a common center.

    Lastly, electrons orbiting the nucleus of an atom has nothing to do with gravity.
  4. Oct 21, 2007 #3


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    Electrons don't orbit in the same sense that astronomical objects do. Electrons are at various energy levels in the neighborhood of the nucleus.
  5. Oct 26, 2007 #4
    True, and these energy levels are really just points in space around the nucleus where there is a high probability of finding an electron. Also, the electrons also differ in that their position and speed may never be determined simultaneously due to Heisenberg's uncertainty principle.

    As for the galaxies orbiting a common senter of gravity, it is actually a bit hard to conclude on this as there seems to be a lot more (dark) matter in the universe than what is accounted for at the present, so some galaxies and stars seem to be orbiting some mass excerting gravitational force, though this mass has not yet been found.
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