Friedmann-Robertson-Walker models do not require zero active mass

Abstract

The $R_h=ct$ cosmological model has received considerable attention in recent years owing to claims that it is favoured over the standard $\Lambda$ cold dark matter ($\Lambda$CDM) model by most observational data. A key feature of the $R_h=ct$ model is that the zero active mass condition $\rho +3p=0$ holds at all epochs. Most recently, Melia has claimed that this condition is a requirement of the symmetries of the Friedmann-Robertson-Walker (FRW) spacetime. We demonstrate that this claim is false and results from a flaw in the logic of Melia's argument.

4 pages, accepted for publication in MNRAS

References in corpus (6)

• We do not live in the R_h = c t universe
• Robust model comparison disfavors power law cosmology
• Physical Basis for the Symmetries in the Friedmann-Robertson-Walker Metric
• The Zero Active Mass Condition in Friedmann-Robertson-Walker Cosmologies
• A Comparison of Cosmological Models Using Time Delay Lenses
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Cited by in corpus (9)

• The Zero Active Mass Condition in Friedmann-Robertson-Walker Cosmologies
• Model Comparison of $\Lambda$CDM vs $R_h=ct$ using Cosmic Chronometers
• Power law cosmology model comparison with CMB scale information
• Testing the Distance-Duality Relation in the $R_h=ct$ Universe
• Alternative ideas in cosmology
• Primordial Nucleosynthesis in the Rh = ct cosmology: Pouring cold water on the Simmering Universe
• A Distance-Deviation Consistency and Model-Independent Method to Test the Cosmic Distance-Duality Relation
• Puzzling initial conditions in the R_h=ct model
• Is there a Cosmological Basis for E = mc^2?