2010/09/30 by Simon Foreman, A. Moss, Adam Moss +4 · 17 citations
Computer Science · Earth and Planetary Sciences · Physics and Astronomy · #Computer Graphics and Visualization Techniques #Computer science #Cosmology and Gravitation Theories #Environmental science #Materials science #Meteorological Phenomena and Simulations #Void (composites) #astro-ph.CO
paper · pdf · doi:10.1103/physrevd.82.103532
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 82(10) (American Physical Society) · 7 pages, 4 figures; revised to match accepted version
arxiv created 2010/11/03 · openalex publication_date 2010/11/24 · arxiv updated 2010/12/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
There has been considerable interest in recent years in cosmological models in which we inhabit a very large, underdense void as an alternative to dark energy. A long-standing objection to this proposal is that observations limit our position to be very close to the void center. By selecting from a family of void profiles that fit supernova luminosity data, we carefully determine how far from the center we could be. To do so, we use the observed dipole component of the cosmic microwave background, as well as an additional stochastic peculiar velocity arising from primordial perturbations. We find that we are constrained to live within 80 Mpc of the center of a void---a somewhat weaker constraint than found in previous studies, but nevertheless a strong violation of the Copernican principle. By considering how such a Gpc-scale void would appear on the microwave sky, we also show that there can be a maximum of one of these voids within our Hubble radius. Hence, the constraint on our position corresponds to a fraction of the Hubble volume of order 10^\ensuremath-8. Finally, we use the fact that void models only look temporarily similar to a cosmological-constant-dominated universe to argue that these models are not free of temporal fine-tuning.