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A little bit of cosmographic sanity

Finally, an interesting paper on dark energy.

Cosmographic analysis of dark energy [http://arxiv.org/abs/0906.5407]

Authors: Matt Visser (Victoria University of Wellington), Celine Cattoen (Victoria University of Wellington)

Abstract: The Hubble relation between distance and redshift is a purely cosmographic relation that depends only on the symmetries of a FLRW spacetime, but does not intrinsically make any dynamical assumptions. This suggests that it should be possible to estimate the parameters defining the Hubble relation without making any dynamical assumptions. To test this idea, we perform a number of inter-related cosmographic fits to the legacy05 and gold06 supernova datasets, paying careful attention to the systematic uncertainties. Based on this supernova data, the “preponderance of evidence” certainly suggests an accelerating universe. However we would argue that (unless one uses additional dynamical and observational information, and makes additional theoretical assumptions) this conclusion is not currently supported “beyond reasonable doubt”. As part of the analysis we develop two particularly transparent graphical representations of the redshift-distance relation — representations in which acceleration versus deceleration reduces to the question of whether the relevant graph slopes up or down.

This entry was posted on July 1, 2009 at 10:23 am and is filed under Astronomy, Cosmology, Physics, Science . You can follow any responses to this entry through the RSS 2.0 feed Both comments and pings are currently closed.

2 Responses to “A little bit of cosmographic sanity”

  1. mitchell porter Says:
    July 6, 2009 at 10:22 pm

    What is boring about the rest of the literature on dark energy? (This is your opportunity to sum it up in a few words.)

  2. ccdantas Says:
    July 7, 2009 at 10:21 am

    Hi Mitchell,

    The observational aspects leading to the “dark energy” problem are fascinating and need to be scrutinized to the extreme (and new data always very welcomed); the problem that I have is with the 1000+ papers offering theories of all sorts and kinds without first focusing on more basic and critical aspects of the data. I do not agree that the existence of dark energy is an issue beyond all doubt, but only quite suggestive, specially the combined, independent data. Implicit dynamical assumptions are, however, usually made — they should be re-evaluated. This paper raises some critical points to which care should be taken.

    Best,
    Christine

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