Dark energy and the Hubble age

L. M. Krauss

doi:10.1086/382121

Dark energy and the Hubble age

L. M. Krauss

Research output: Contribution to journal › Article › peer-review

12 Scopus citations

Abstract

I point out that an effective upper limit of approximately 20(0.2/ω_m)^1/2 Gyr (for a Hubble constant of 72 km s^-1 Mpc^-1), or alternatively, 1.49(0. 2/ω_m)^1/2 for the H₀-independent quantity H₀t₀, exists on the age of the universe, essentially independent of the unknown equation of state of the dominant dark energy component in the universe. If astrophysical constraints on the age of the universe can convincingly reduce the upper limit to well below this value, a useful lower limit on the equation of state parameter w for this component can be obtained. Direct dating by stars does not provide a useful constraint, but model-dependent cosmological limits from supernovae and the CMB observations can do so.

Original language	English (US)
Pages (from-to)	481-483
Number of pages	3
Journal	Astrophysical Journal
Volume	604
Issue number	2 I
DOIs	https://doi.org/10.1086/382121
State	Published - Apr 1 2004
Externally published	Yes

Keywords

Cosmological parameters
Cosmology: theory
Equation of state
Galaxy: fundamental parameters
Gravitation

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/382121

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AB - I point out that an effective upper limit of approximately 20(0.2/ωm)1/2 Gyr (for a Hubble constant of 72 km s-1 Mpc-1), or alternatively, 1.49(0. 2/ωm)1/2 for the H0-independent quantity H0t0, exists on the age of the universe, essentially independent of the unknown equation of state of the dominant dark energy component in the universe. If astrophysical constraints on the age of the universe can convincingly reduce the upper limit to well below this value, a useful lower limit on the equation of state parameter w for this component can be obtained. Direct dating by stars does not provide a useful constraint, but model-dependent cosmological limits from supernovae and the CMB observations can do so.

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Dark energy and the Hubble age

Abstract

Keywords

ASJC Scopus subject areas

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