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Related papers: Do anthropic arguments really work?

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The anthropic principle is one of the possible explanations for the cosmological constant ($\Lambda$) problem. In previous studies, a dark halo mass threshold comparable with our Galaxy must be assumed in galaxy formation to get a…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-15 Takahiro Sudoh , Tomonori Totani , Ryu Makiya , Masahiro Nagashima

The observed value $\Lambda_{\rm obs}$ of the cosmological constant $\Lambda$ is extremely smaller than theoretical expectations, and the anthropic argument has been proposed as a solution to this problem because galaxies do not form when…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-09 Tomonori Totani , Hidetoshi Omiya , Takahiro Sudoh , Masakazu A. R. Kobayashi , Masahiro Nagashima

We present an extended analytic model for cosmic star formation, with the aim of investigating the impact of cosmological parameters on the star formation history within the $\Lambda$CDM paradigm. Constructing an ensemble of flat…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-13 Daniele Sorini , John A. Peacock , Lucas Lombriser

Selection effects in cosmology are often invoked to "explain" why some of the fundamental constant of Nature, and in particular the cosmological constant, take on the value they do in our Universe. We briefly review this probabilistic…

Astrophysics · Physics 2009-11-11 Roberto Trotta , Glenn D. Starkman

We revisit anthropic arguments purporting to explain the measured value of the cosmological constant. We argue that different ways of assigning probabilities to candidate universes lead to totally different anthropic predictions. As an…

Astrophysics · Physics 2007-07-23 Glenn D. Starkman , Roberto Trotta

Models of the very early universe, including inflationary models, are argued to produce varying universe domains with different values of fundamental constants and cosmic parameters. Using the cosmological hydrodynamical simulation code…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-10 Luke A. Barnes , Pascal J. Elahi , Jaime Salcido , Richard G. Bower , Geraint F. Lewis , Tom Theuns , Matthieu Schaller , Robert A. Crain , Joop Schaye

The existence of multiple regions of space beyond the observable Universe (within the so-called "multiverse") where the vacuum energy density takes different values, has been postulated as an explanation for the low non-zero value observed…

Astrophysics · Physics 2009-11-11 Abraham Loeb

This paper investigates anthropic bounds on the vacuum energy $\Lambda$. We first consider the possibility of cosmic observers existing at any random time (including the future) for constant $\Lambda$, and take into account the suppression…

General Relativity and Quantum Cosmology · Physics 2009-01-22 L. Mersini-Houghton , F. Adams

We compute the expected value of the cosmological constant in our universe from the Causal Entropic Principle. Since observers must obey the laws of thermodynamics and causality, the principle asserts that physical parameters are most…

High Energy Physics - Theory · Physics 2008-11-26 Raphael Bousso , Roni Harnik , Graham D. Kribs , Gilad Perez

We re-examine claims that anthropic arguments provide an explanation for the observed smallness of the cosmological constant, and argue that correlations between the cosmological constant value and the existence of life can be demonstrated…

High Energy Physics - Theory · Physics 2008-11-26 Irit Maor , Lawrence Krauss , Glenn Starkman

The usage of the anthropic principle in modern cosmology is reviewed. It is argued that its recent use to explain the observedvalues of cosmological parameters as most probable values for an ensemble of universes, is not justified. However,…

Astrophysics · Physics 2016-11-23 Berndt Müller

The causal entropic principle has been proposed as a superior alternative to the anthropic principle for understanding the magnitude of the cosmological constant. In this approach, the probability to create observers is assumed to be…

High Energy Physics - Theory · Physics 2008-11-26 James M. Cline , Andrew R. Frey , Gilbert Holder

Anthropic reasoning often begins with the premise that we should expect to find ourselves typical among all intelligent observers. However, in the infinite universe predicted by inflation, there are some civilizations which have spread…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Ken D. Olum

The anthropic principle has been proposed as an explanation for the observed value of the cosmological constant. Here we revisit this proposal by allowing for variation between universes in the amplitude of the scale-invariant primordial…

High Energy Physics - Theory · Physics 2007-05-23 Michael L. Graesser , Stephen D. H. Hsu , Alejandro Jenkins , Mark B. Wise

We present a new solution to the cosmological constant (CC) and coincidence problems in which the observed value of the CC, $\Lambda$, is linked to other observable properties of the universe. This is achieved by promoting the CC from a…

General Relativity and Quantum Cosmology · Physics 2015-03-17 Douglas J. Shaw , John D. Barrow

Anthropic models can give testable predictions, which can be confirmed or falsified at a specified confidence level. This is illustrated using the successful prediction of the cosmological constant as an example. The history and the nature…

Astrophysics · Physics 2007-06-20 Alexander Vilenkin

In some cosmological theories with varying constants there are anthropic reasons why the expansion of the universe must not be too {\it close} to flatness or the cosmological constant too close to zero. Using exact theories which…

Astrophysics · Physics 2009-11-07 J. D. Barrow , H. B. Sandvik , J. Magueijo

I review the major concordances and controversies of the meeting concerning observations. Cosmologists are nearing agreement on the global cosmological parameters of the Universe. A few parameters still have large error bars, notably…

Astrophysics · Physics 2009-09-29 S. M. Faber

A general Friedmann big-bang cosmology can be specified by fixing a half-dozen cosmological parameters such as the photon-to-baryon ratio Eta, the cosmological constant Lambda, the curvature scale R, and the amplitude Q of (assumed…

Astrophysics · Physics 2009-11-06 Anthony Aguirre

The influence of recent detections of a finite vacuum energy ("cosmological constant") on our formulation of anthropic conjectures, particularly the so-called Final Anthropic Principle is investigated. It is shown that non-zero vacuum…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Milan M. Cirkovic , Nick Bostrom
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