# The cosmic equation of state

@article{Melia2014TheCE, title={The cosmic equation of state}, author={Fulvio Melia}, journal={Astrophysics and Space Science}, year={2014}, volume={356}, pages={393-398} }

The cosmic spacetime is often described in terms of the Friedmann-Robertson-Walker (FRW) metric, though the adoption of this elegant and convenient solution to Einstein’s equations does not tell us much about the equation of state, p=wρ, in terms of the total energy density ρ and pressure p of the cosmic fluid. ΛCDM and the Rh=ct Universe are both FRW cosmologies that partition ρ into (at least) three components, matter ρm, radiation ρr, and a poorly understood dark energy ρde, though the…

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