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Johnjbarton (talk | contribs) →S8 tension: Ref says "The tension in the S8 parameter (or in the related σ8 parameter) has added yet another question mark over the validity of the standard �CDM cosmology." |
Johnjbarton (talk | contribs) →Overview: Some how the author was missing |
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== Overview ==
The ΛCDM model is based on three postulates on the structure of [[spacetime]]:<ref name="Longair-2009">{{Cite book|date=2008 |title=Galaxy Formation
|author=Malcolm S. Longair |url=http://link.springer.com/10.1007/978-3-540-73478-9 |series=Astronomy and Astrophysics Library |language=en |___location=Berlin, Heidelberg |publisher=Springer Berlin Heidelberg |doi=10.1007/978-3-540-73478-9 |isbn=978-3-540-73477-2}}</ref>{{rp|227}} # The [[cosmological principle]], that the universe is the same everywhere and in all directions, and that it is expanding,
# A postulate by [[Hermann Weyl]] that the lines of spacetime ([[geodesics]]) intersect at only one point, where time along each line can be synchronized; the behavior resembles an expanding fluid,<ref name="Longair-2009"/>{{rp|175}}
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