The Gravitational Horizon for a Universe with Phantom Energy

Abstract

The Universe has a gravitational horizon, coincident with the Hubble sphere, that plays an important role in how we interpret the cosmological data. Recently, however, its significance as a true horizon has been called into question, even for cosmologies with an equation-of-state w = p/rho > -1, where p and rho are the total pressure and energy density, respectively. The claim behind this argument is that its radius R_h does not constitute a limit to our observability when the Universe contains phantom energy, i.e., when w < -1, as if somehow that mitigates the relevance of R_h to the observations when w > -1. In this paper, we reaffirm the role of R_h as the limit to how far we can see sources in the cosmos, regardless of the Universe's equation of state, and point out that claims to the contrary are simply based on an improper interpretation of the null geodesics.

9 pages, 1 figure. Slight revisions in refereed version. Accepted for publication in JCAP. arXiv admin note: text overlap with arXiv:1112.4774

References in corpus (5)

• Cosmology and the Fate of Dilatation Symmetry
• The R_h = ct Universe
• Photon Geodesics in FRW Cosmologies
• How does the Hubble Sphere limit our view of the Universe?
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• A Test of Cosmological Models using high-z Measurements of H(z)
• Matter Matters: Unphysical Properties of the Rh = ct Universe
• A Solution to the electroweak horizon problem in the R_h=ct universe
• Cosmological Tests With Strong Gravitational Lenses using Gaussian Processes
• Friedmann-Robertson-Walker models do not require zero active mass
• The $R_{\mathrm{h}}=ct$ universe and quintessence
• The Origin of Rest-mass Energy
• Puzzling initial conditions in the R_h=ct model
• Phantom Energy and the Cosmic Horizon: Rh is still not a horizon!
• Studies of Quantum Chromodynamics at the LHC
• Cosmological Perturbations without Inflation
• The Electroweak Horizon Problem
• Ray tracing in FLRW flat space-times