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Questions about Spiral Galaxies

  1. Aug 6, 2011 #1
    So I was watching this:

    which talks about the winding paradox of spiral galaxies, e.g. the stars all move at the same relative speed however that shape is maintained. However, we still have those shapes.
    The video talks about density waves of some sort. I don't really understand. This can't be some sort of probability density coming from wave amplitude like in quantum mechanics, or is it?

    Anyone care to elaborate or if you have your own explanation?

    Last edited by a moderator: Sep 25, 2014
  2. jcsd
  3. Aug 7, 2011 #2
    You are correct, it has nothing to do with quantum mechanics. Unfortunately I do not know much more on this topic than is in that video and on the http://en.wikipedia.org/wiki/Density_wave_theory" [Broken]. The wikipedia page has several animations that help demonstrate some of the ideas you heard about in the video.
    Last edited by a moderator: May 5, 2017
  4. Aug 7, 2011 #3


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  5. Aug 7, 2011 #4
    Thanks for the sources, it helped a lot :)
  6. Sep 15, 2011 #5
  7. Nov 1, 2011 #6


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  8. Nov 22, 2011 #7
    Yeah that star with the spiral arms is very interesting, i would like to see more pictures of it :S
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