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Why most of the galaxies are having two spiral arms only?

  1. Oct 24, 2011 #1
    why most of the galaxies are having two spiral arms only?
     
  2. jcsd
  3. Oct 24, 2011 #2

    mathman

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  4. Oct 24, 2011 #3

    phinds

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    Re: galaxy,arms

    Yes, I agree w/ mathman. What gave you the idea that 2 arms was the norm? Can you give a reference?
     
  5. Oct 24, 2011 #4
    Re: galaxy,arms

    I have never heard of a galaxy with only two arms, although if there was such a thing, that would be interesting to see.
     
  6. Oct 24, 2011 #5

    phinds

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    Re: galaxy,arms

    I may be wrong, but I DO seem to remember once (and only once) seeing a pic of a galaxy with only two arms ... or it might be that it only SEEMED to have just two arms because the two were so much stronger than the others ... I can't really recall.
     
  7. Oct 25, 2011 #6

    mathman

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    Re: galaxy,arms

    Barred spirals may have only two arms, each coming off an end of the bar.
     
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