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Evidence for stellar evolution since the Big Bang

  1. Jul 25, 2009 #1
    Is it generally true that the further away a galaxy is (and more red-shifted), the more it tends to contain lower metal content stars? I'd always assumed this was one of the main bits of evidence for the Big Bang, but I've also read that the globular clusters that surround (and are gravitationally bound to) large galaxies such as our own contain mostly "old" (primitive, 2nd generation?) stars. (I realize that these facts are not necessarily contradictory, but I'd like to know what the astronomy community thinks about it.)
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  3. Jul 26, 2009 #2


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    The metallicity of stars does not differ significantly over time [redshift distance]. This is widely viewed as evidence metallicity evolved very rapidly in the early universe. We also do not see population 1 stars in the universe for presumably the same reason. Our understanding of galactic [and stellar] evolution is still very primitive at present. Better instruments, like the James Webb telescope, will help.
  4. Jul 26, 2009 #3
    Thanks for the reply, Chronos.

    Is the lack of correlation with distance also true of heavier metals, such as iron?

    More importantly, despite the primitiveness of our understanding of galactic evolution, is there good evidence that the galaxies further away are clearly more primitive in any sense? I'm simply wondering what galactic or stellar evidence there is against a steady state model of the universe, as opposed to the current Big Bang model.

    Perhaps my thread should've been labeled "evidence for galaxy evolution...".
  5. Jul 28, 2009 #4


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    Unfortunately, distant galaxies are abnormally large and bright as a function of redshift distance. It stands to reason they are more evolved than their younger, invisible neighbors. The most significant evidence against steady state cosmology is the cosmic microwave background [CMB]. It is a stake in the heart.
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