Testing anthropic predictions for and the cosmic microwave background temperature
Open accessAbstract
It has been claimed that the observed magnitude of the vacuum energy density is consistent with the distribution predicted in anthropic models, in which an ensemble of universes is assumed. This calculation is revisited, without making the assumption that the cosmic microwave background (CMB) temperature is known, and considering in detail the possibility of a recollapsing universe. New accurate approximations for the growth of perturbations and the mass function of dark haloes are presented. Structure forms readily in the recollapsing phase of a model with negative Λ, so collapse fraction alone cannot forbid Λ from being large and negative. A negative Λ is disfavoured only if we assume that formation of observers can be neglected once the recollapsing universe has heated to T≳ 8 K. For the case of positive Λ, however, the current universe does occupy an extremely typical position compared to the predicted distribution on the Λ−T plane. Contrasting conclusions can be reached if anthropic arguments are applied to the curvature of the universe, and we discuss the falsifiability of this mode of anthropic reasoning.
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The universe re-collapses before life can form for rho_L greater than about -10^-121.
“The universe re-collapses before life can form for r L t À10 À121 (Peacock 2007).”
From The Fine-Tuning of the Universe for Intelligent Life (2012) · cites this paper as Peacock 2007
Section 3 says that highly negative vacuum densities can make the universe turn around before it cools enough for observer formation. That is the opposite direction from the claimed threshold of greater than −10^-121. Our copy also does not state that numerical threshold. (LLM, conf=0.86)
Checked by a reasoning model — may be wrong.
Experimental — accuracy not yet measuredQuintessence models must be fine-tuned in exactly the same way as the cosmological constant.
“Quintessence models must be fine-tuned in exactly the same way as the cosmological constant (see also Durrer & Maartens 2007).”
From The Fine-Tuning of the Universe for Intelligent Life (2012) · cites this paper as Peacock (2007)
The Introduction says a simple quintessence model appears to require introducing an energy scale by hand, and that quintessence models do not solve the scale problem. It does not say that all quintessence models must be fine-tuned in exactly the same way as the cosmological constant. Page numbers are unavailable in our copy. (LLM, conf=0.86)
Experimental — accuracy not yet measuredStenger's assertion that there is no fine-tuning problem for quintessence is false.
“Stenger's assertion that there is no fine-tuning problem for quintessence is false, as a number of authors have pointed out.”
From The Fine-Tuning of the Universe for Intelligent Life (2012) · cites this paper as Peacock (2007)
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Cites
The cosmological constant problem
Weinberg, S. (1989) · Reviews of Modern Physics · doi:10.1103/revmodphys.61.1 · Cited by 7,341 · cited 3× · see citing works
“In the end, we are persuaded by the original view of Weinberg (1989), who took the prior on Λ to be uniform over a small range around zero (see also Efstathiou 1995 and Weinberg 2000).”
MethodInfluentialDimensionless constants, cosmology, and other dark matters
Tegmark, M., Aguirre, A., Rees, M. J., & Wilczek, F. (2006) · Physical Review D · doi:10.1103/physrevd.73.023505 · Cited by 401 · cited 1× · see citing works
“The most radical view is that of the string-theory landscape, in which all of physics is free to vary (Susskind 2003), and aspects of this picture have been explored by e.g. Tegmark et al. (2006) and Graesser & Salem (2006).”
BackgroundCosmological constant and the time of its dominance
Garriga, J., Livio, M., & Vilenkin, A. (1999) · Physical Review D · doi:10.1103/physrevd.61.023503 · Cited by 115 · see citing works
Flagged first, then by citations
Research works printed but not linked: 9
- Barrow J. D., Tipler F. J., 1986, The Anthropic Cosmological Principle. Oxford Univ. Press, Oxford
- Longair M. S., ed., Proc. IAU Symp. 63, Confrontation of Cosmological Theories with Observational Data. Reidel, Dordrecht, p. 291
- Graesser M. L., Salem M. P., 2006, online-only reference (astro-ph/0611694) · arXiv
- Linde A. D., 1987, in Hawking S. W., Israel W., eds, 300 Years of Gravitation. Cambridge Univ. Press, Cambridge, p. 604
- Neal R. M., 2006, online-only reference (math.ST/0608592) · arXiv
- Olum K. D., 2002, Philosophical Quarterly, 52, 164
- Peacock J. A., 1999, Cosmological Physics. Cambridge Univ. Press, Cambridge
- Peebles P. J. E., 1980, The Large-Scale Structure of the Universe. Princeton Univ. Press, Princeton NJ Press W.
- Susskind L., 2003, online-only reference (hep-th/0302219) · arXiv
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Sorted by citations
The Fine-Tuning of the Universe for Intelligent Life
Barnes, L. A. (2012) · Publications of the Astronomical Society of Australia · doi:10.1071/as12015 · Cited by 150 · see citing works
“For example, Peacock (2007) notes that most models of quintessence in the literature specify its properties via a potential V(f), and comments that ‘Quintessenceymodels do not solve the [cosmological constant] problem: the potentials asymptote to zero, even though there is no known symmetry that…”
Background
- Authors
- Peacock, J. A.
- Affiliations
- Royal Observatory (GB)
- Corresponding author
- Peacock, J. A.
- ORCID
- Peacock, J. A.
- Venue
- Monthly Notices of the Royal Astronomical Society
- Publisher
- Oxford University Press (OUP)
- Published
- 2007-08-11
- Volume
- 379
- Issue
- 3
- Pages
- 1067-1074
- ISSN
- 0035-8711 (ISSN-L)
- 1365-2966
- OpenAlex
- W1895140248
- Cited by
- 44
- References
- 3
- Citations by year
- 2026: 2 · 2024: 3 · 2023: 4 · 2022: 1 · 2021: 1 · 2019: 3 · 2018: 5 · 2017: 3 · 2016: 2 · 2015: 3 · 2014: 1 · 2013: 2 · 2012: 2
- FWCI
- 1.60
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Monthly Notices of the Royal Astronomical Society (publishedVersion)
- arXiv (Cornell University) (acceptedVersion)
- arXiv (Cornell University)
- Topics
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Cosmology and Gravitation Theories
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Galaxies: Formation, Evolution, Phenomena
- Physical Sciences › Physics and Astronomy › Nuclear and High Energy Physics › Dark Matter and Cosmic Phenomena
- Keywords
- anthropic principle, cosmic microwave background temperature, vacuum energy density, cosmological constant, negative cosmological constant, halo mass function, perturbation growth, typicality, multiverse
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