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Thread: age of far off galaxies.

  1. #1
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    age of far off galaxies.

    Is there a way to age objects in galaxies, lets say 8 billion light years away?
    The moment an instant lasted forever, we were destined for the leading edge of eternity.

  2. #2
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    Unless you are talking about creating whiskey at high redshifts, your question doesn't make much sense. Could you ask it again, perhaps with more details or background? What exactly do you want to know?

  3. #3
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    The verb to age meaning "determine the age of" rather than "allow to mature by the passage of time", I think.

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    Quote Originally Posted by StupendousMan View Post
    Unless you are talking about creating whiskey at high redshifts, your question doesn't make much sense. Could you ask it again, perhaps with more details or background? What exactly do you want to know?
    Is there a way to age stars, within a galaxy 8 billion, years away. Can we look at one star in the galaxy and say it looks 4 billion year old at the time it was emitted.
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  5. #5
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    It's hard to judge the age of single star. However, it's generally possible to determine the age of a cluster of stars. Since the stars in a cluster form at roughly the same time, but the higher mass stars move off the main sequence earlier, finding the highest mass stars in the cluster that are still on the main sequence gives a good indication of the age. A young cluster will still have many massive stars on the main sequence, but in an old cluster, all those stars will have moved to other stages.

    So the clusters in and around a galaxy can provide an indication of the age of the galaxy itself. There are other techniques as well, which can be used to cross reference each other and confirm that the estimates are reasonable.
    Conserve energy. Commute with the Hamiltonian.

  6. #6
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    Grey is correct, but the method he describes is pretty much impossible to employ at the distances described by the original post. At high redshifts, we can't resolve individual stars in a cluster, or even individual clusters of stars. The best we can do is to measure the colors of groups of clusters in star-forming regions. That can provide a general idea of the age of some of the stars in those galaxies, but with considerable uncertainties.

    Moreover, the brightest stars --- the ones which dominate the light we can measure --- tend to be very young. Even if a distant galaxy might contain an old stellar population, it would be difficult for us to observe it.

    Perhaps you might read this article to get an idea for some of the recent work in the area:

    https://arxiv.org/abs/1912.00084

  7. #7
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    Halton Arp and others have argued that "redshift" is intrinsic to the objects and not "cosmological" in nature, therefore cannot be a reliable indicator of age, distance or recessional velocity. Arp published extensively on the subject:

    https://www.haltonarp.com/articles

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    Quote Originally Posted by showmeonthedollwhere View Post
    Halton Arp and others have argued that "redshift" is intrinsic to the objects and not "cosmological" in nature, therefore cannot be a reliable indicator of age, distance or recessional velocity. Arp published extensively on the subject:

    https://www.haltonarp.com/articles

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    showmeonthedollwhere

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  9. #9
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    Quote Originally Posted by StupendousMan View Post
    Grey is correct, but the method he describes is pretty much impossible to employ at the distances described by the original post.
    Ah, right. Didn't notice that distance in the first post. Oops.
    Conserve energy. Commute with the Hamiltonian.

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