Cosmography: Cosmology without the Einstein equations
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How much of modern cosmology is really cosmography? How much of modern cosmology is independent of the Einstein equations? (Independent of the Friedmann equations?) These questions are becoming increasingly germane—as the models cosmologists use for the stress-energy content of the universe become increasingly baroque, it behaves us to step back a little and carefully disentangle cosmological kinematics from cosmological dynamics. The use of basic symmetry principles (such as the cosmological principle) permits us to do a considerable amount, without ever having to address the vexatious issues of just how much “dark energy”, “dark matter”, “quintessence”, and/or “phantom matter” is needed in order to satisfy the Einstein equations. This is the sub-sector of cosmology that Weinberg refers to as “cosmography”, and in this article I will explore the extent to which cosmography is sufficient for analyzing the Hubble law and so describing many of the features of the universe around us.
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- 2.Weinberg, S.: Gravitation and cosmology: Principles and Applications of the General Theory of relativity. Wiley, New York (1972)Google Scholar
- 4.Riess, A.G., et al.: Type Ia supernova discoveries at z > 1 from the Hubble space telescope: Evidence for past deceleration and constraints on dark energy evolution. Astrophys. J. 607, 665 (2004) [arXiv:astro-ph/0402512]Google Scholar
- 5.Caldwell, R.R., Kamionkowski, M.: Expansion, geometry, and gravity. JCAP 0409:009 (2004) [arXiv:astro-ph/0403003]Google Scholar