The cosmic equation of state

  title={The cosmic equation of state},
  author={Fulvio Melia},
  journal={Astrophysics and Space Science},
  • F. Melia
  • Published 21 November 2014
  • Physics
  • Astrophysics and Space Science
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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