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Is There An Age Problem In The Early LCDM Model?

  1. Jun 30, 2010 #1

    Garth

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    A paper written by Authors: Rong-Jia Yang, Shuang Nan Zhang, published in Mon. Not. R. Astron. Soc. 000, 1–7 (2009) and modified on today's Physics ArXiv asks a question we have looked at before on PF, "Is there an age problem in the early universe of the [itex]\Lambda[/itex]CDM model?"

    At high red shift some objects are observed that appear to be older than the universe in that epoch. In the previous thread linked to above we considered APM 08279+5255 and then (2005) concluded further work needs to be done to reassess its age. Yang and Zhang's paper does just this using WMAP5 data and seem to have hardened the problem.

    From the paper's conclusion:
    Garth
     
    Last edited: Jun 30, 2010
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  3. Jul 1, 2010 #2

    Chalnoth

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    The real problem is that this particular quasar is significantly more iron-rich than a 1.7 billion-year-old quasar would be expected to be. Given the wide variety of other independent observations we have, I don't think finding a bit more iron than expected is likely to overturn any cosmological models.
     
  4. Jul 1, 2010 #3

    It should be noted that the estimated values of the standard model parameters are dependent on theoretical assumptions associated with the analysis of the observations.

    For example Shanks’ et al's alleged beam correction for the CMB analysis (Shanks used a distant object to calibrate the WMAP data analysis rather than Jupiter) which significantly affects both the position and magnitude of the first peak in the CMB analysis such that the analysis no longer supports the specific parameter values in the standard model. An incorrect fundamental data analysis and interpretation is particularly egregious as it blocks any thought concerning alternatives. (i.e. We believe the CMB data proves/proved the hypothesis is correct, therefore any unexplained anomaly must be either bad data or a lack of knowledge of the underlying mechanisms.)

    One of the points of Shanks’ discussion with the other specialists on the CMB analysis is that there is a natural tendency to adjust the analysis to match what people believe is the scientific consensus. Observations and analysis that is alleged to provide independent support for a hypothesis may therefore not be independent. The affect is caused by group think, theory ripening, (Ideas that are widely repeated, believed for long periods of time, and written in text books become assumed absolute truths.) and theory momentum.

    As I noted in the thread “Dark Matter, On the Ropes?” there is theoretical and observational data (variance of the spiral galaxy rotational curve with radius, number of satellite galaxies, size of the spiral galaxy’s bulge and the negative results for the direct detection of dark matter) that directly challenges the existence of dark matter.

    The creation of new primitives such as dark matter and dark energy is brilliant if the new primitive does exist. If the hypothesized new primitive truly does not exist, there is still a physical explanation for the observations.
     
  5. Jul 1, 2010 #4

    Garth

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    Yes, but three times solar iron abundance will take some explaning to reconcile with the present standard model, especially as iron is the last element to be produced in stellar exothermic nuclear reactions.

    Just as SN Ia observations radically introduced acceleration into the standard comological model over a decade ago perhaps this observation (and other objects - see the 2005 discussion in the thread linked to above) may cause the present standard model to be revised.

    So, for example, if DE applied to early epochs, then that would extend the age of the universe observed at high z. On the other hand it might also modify BBN relative abundance ratios, which would need to be reworked, but I think the possibility is worth considering.

    Saul I agree that the confidence placed in the standard model sometimes leads to anomalous observations being dismissed too lightly, however you have to do the analysis of those observations within a coherent theoretical framework.

    Garth
     
    Last edited: Jul 1, 2010
  6. Jul 1, 2010 #5

    Chalnoth

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    Yes. But so is this observation. It's still just a larger than expected amount of iron, and this could still be due to some rather peculiar circumstances that occurred in this particular quasar. And interpreting that as an age requires a physical model of how rapidly the iron abundance can increase, a physical model that also could be wrong. If we start seeing other, independent observations that also give indications that our universe must be older, yeah, I'll buy that there's a possibility that this is saying that the universe is actually older. But until then, the possibility that the quasar model is wrong is by far the expected answer to this.

    Granted, but again, this is just one quasar. If you want to look for something unusual, with the sheer number of astronomical objects out there, I'm sure you can find it. So even if it is a very large amount of iron, we would need multiple bits of independent, mutually-corroborating evidence to suggest that this requires an older universe. Until we have that, "It's just a weird quasar," is far more likely.
     
  7. Jul 2, 2010 #6

    Chronos

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    I think it points more in the direction of our incomplete understanding of nucleosynthesis than an age problem.
     
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