RE: The Star-Trek effect

From: Glenn Morton (
Date: Wed Jan 23 2002 - 22:06:03 EST

  • Next message: Glenn Morton: "RE: The Star-Trek effect"

    Hi George,

    >-----Original Message-----
    >From: george murphy []
    >Sent: Wednesday, January 23, 2002 2:02 AM
    >To: Glenn Morton
    > You've read Whewell & I only summaries of him, & I don't
    >want to dispute
    >your basic point about the tendentious character of his argument.
    > But in the mid-18th century "the nebulae" included a
    >number of different
    >kinds of objects. There were some objects that did indeed consist
    >of individual
    >stars with or without other "nebulosity"
    >that are within the Milky Way, like the Orion Nebula. But there
    >were others
    >like M31 that we now know to be external galaxies but that
    >couldn't be resolved
    >into stars at that time. The latter are the ones that had been
    >hypothesized to
    >be "island universes" by some, but this claim was disputed by others. It's
    >really this "island universe" idea that was being debated &, as I
    >noted, the
    >debate wasn't settled till ~70 years after Whewell wrote.
    > I'll be out of touch for ~1week. (Some will say I have
    >been for a long

    I will answer you and await your response when you get back, if you care to
    respond. From what I recall of my time as an astronomy major in college
    (many years ago and quickly and forcibly moved to physics) the controversy
    about the galaxies which Hubble solved was NOT whether or not they were
    collections of stars--that was settled prior to Whewell for all except
    Whewell. What the issue was, concerned the location of these collections of
    stars. Where the nebulas within the Milky Way or outside of it? That is
    what Hubble solved. Since all my astronomy books are locked up in a Houston
    storage vault, I can only offer this as support:

    " In the early 1920's Hubble played a key role in establishing just what
    galaxies are. It was known that some spiral nebulae (fuzzy clouds of light
    on the night sky) contained individual stars, but there was no consensus as
    to whether these were relatively small collections of stars within our own
    galaxy, the 'Milky Way' that stretches right across the sky, or whether
    these could be separate galaxies, or 'island universes', as big as our own
    galaxy but much further away. "

    And even in the great 1920 debate between Shapley and Curtis, where Shapley
    was arguing against the nebulae being outside of our galaxy, Shapley
    acknowledged that there were stars in the nebula and used this as an
    argument in his favor saying:

    "c. If our galaxy approaches the larger order of dimensions, a serious
    difficultly at once arises for the theory that spirals are galaxies of stars
    comparable in size with our own: it would be necessary to ascribe impossibly
    great magnitudes to the new stars that have appeared in the spiral nebulae.

    THus I respectfully submit the issue in the 20's was not whether the nebulae
    were stars but how far the stars were!

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