How do distance and age relate in astronomical measurements?

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Discussion Overview

The discussion revolves around the relationship between distance and age in astronomical measurements, particularly in the context of light years, redshift, and the age of galaxies and globular clusters. Participants explore how these concepts are interrelated and the implications of redshift on age estimations.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant expresses confusion about the concept of a light year as a distance measure, particularly in relation to the age of galaxies and the implications of redshift measurements.
  • Another participant provides links to resources that describe methods for determining the ages of stars, suggesting that redshift is not directly related to age determination.
  • A different participant argues that redshift places limits on the maximum age of astronomical objects, stating specific age and distance relationships for galaxies.
  • A later reply indicates a personal resolution of confusion, thanking other participants for their contributions.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the relationship between redshift and age measurements, with some asserting that redshift limits age while others suggest it is not directly related.

Contextual Notes

The discussion includes assumptions about the definitions of light years and redshift, as well as the implications of these measurements on age estimations, which remain unresolved.

foxpoint11
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I thought i understood a light year as a measure of distance.But i keep running into articles that say something like ...around Galaxy NCG 4921 there are a cluster of galaxies estimated to be 13+ billion years old at a distance of 320 light years from earth.How do you get that when you are measuring red shifts?
Or how do you get "there are globular clusters that appear older than the known universe?"
Thank you for any help.:confused:
 
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Redshift limits the maximum age of objects in the universe. That is to say that a galaxy 13 billion years old cannot be at a redshift distance in excess of about 700 million light years. Similarly, a galaxy 6 billion light years distant cannot be more than about 7.7 billion years old. So NGC 4921 at a distance of 260 million light years could be 13.4 billion years old.
 


By George,I think i have it.Thank you mothman and Chronos.
 

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