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Why are there stars that are "older than the universe"?

  1. Apr 6, 2015 #1
    I'm just wondering why there exist objects like http://en.wikipedia.org/wiki/HD_140283 (The Methuselah Star) that have projected ages older than the projected age of the universe itself. That, where does the conflict between the age of these very old stars and the calculated age of the universe come from?

    Is it a quirk in how star ages are computed, like that these stars are somehow anomalous in their content of gas and other chemicals in relation to their size and luminosity in a way that would interfere with the calculation? Or is there some kind of relativity weirdness that allows for the existence of objects "older" than the universe itself (the star was moving very fast, or was in a very high mass-density region, or was moving in such a way that its redshift interfered with observations)?

    Please help me, I'm very confused.
  2. jcsd
  3. Apr 6, 2015 #2

    Simon Bridge

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  4. Apr 6, 2015 #3


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    Basically, it's really really hard to estimate the ages of stars. The errors on the ages are large, and generally include the measured age of our universe within the errors. Note this sentence from the Wiki page you linked:

    "Due to the uncertainty in the value, this age for the star does not conflict with the age of the Universe determined by the Planck satellite, 13.798 ± 0.037."

    Because the error bars on stellar ages are so large, that a few would be measured to be older than our universe is expected. If we were able to reduce the errors on the ages of these stars, the discrepancy would almost certainly disappear.
  5. Apr 6, 2015 #4
    We can't know the exact age of a star, best we can do is make an estimate based on composition, mass, and apparent state of progress in the HR diagram.
    The estimates are based on models which for most stars produce a credible result.
    It's not relativity weirdness here, just an unusual combination of parameters in this case which are causing the models to produce results with a high error margin.
  6. Apr 7, 2015 #5


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    The age of stars is less certain than the age of the universe, as has already been pointed out. The error bars overlap in a range comfortable to most scientists.
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