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Interstellar Medium

  1. May 23, 2007 #1
    Hey, can anybody tell me what the estimate is on the mean mass of a particle in the interstellar medium? I would guess around 1-10 proton masses?
  2. jcsd
  3. May 23, 2007 #2


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    Just for fun, I will guess too.
    I think you probably mean the ISM in the plane of our galaxy

    I think you mean to average on a MASS basis.

    So if most of the mass is in the form of neutral gas, then for a first approximation of the average, I can neglect dust and ionized stuff.

    Eventually someone who has a definite figure will reply. I would guess the average atomic weight is 2.
    (because I think the ISM is dominated by molecular hydrogen.
    there would also be some neutral atomic hydrogen with weight 1 but that would tend to be balanced out by the heavier molecular species and the dust)

    BTW welcome to physicsforums, Mr. Popffabrik.
    I like the name, it seems it could be a nickname for the LHC collider. "bang factory"
    Last edited: May 23, 2007
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