cosmological constant

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Cosmological models with different deceleration parametersclick for a larger image
Cosmological models with different deceleration parameters

cosmological constant

(koz-mŏ-loj -ă-kăl) A constant term that can be added to Einstein's field equations of general relativity theory. The cosmological constant was originally put forward by Albert Einstein in 1917 to ensure that the application of general relativity theory to the Universe results in a static Universe rather than an expanding or contracting Universe. The discovery that the Universe is expanding removed the necessity for introducing the cosmological constant but cosmological models with a nonzero cosmological constant have been considered by theoreticians.

For many years it was thought that the value of the cosmological constant is exactly zero but, starting in the late 1990s, evidence began to accumulate that the cosmological constant has a small but nonzero value. This has the consequence that the expansion of the Universe is accelerating. There have been many attempts to show why the value of the cosmological constant is either zero or very small but there is no consensus as to why this should be the case.

Collins Dictionary of Astronomy © Market House Books Ltd, 2006
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Cosmological Constant


the constant A introduced by A. Einstein in 1917 into his equations of gravitation (1916) so that these equations would have solutions describing a static universe and would satisfy the requirement of the relativity of inertia. The physical meaning of the introduction of the constant consists in the assumed existence of special cosmic forces (of repulsion at ∧ > 0 and of attraction at ∧ < 0) that increase with distance. Since the requirement of a static universe became redundant with the discovery that galaxies are receding from one another, Einstein abandoned the cosmological constant in 1931. From this time on, it was assumed that ∧ ≡ 0. Another possibility is being considered at present (the 1970’s), namely, that the cosmological constant is extremely small (∽10−55 cm−2).


Zel’dovich, la. B., and I. D. Novikov. Reliativistskaia astrofizika. Moscow, 1967.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

cosmological constant

[¦käz·mə¦läj·ə·kəl ′kän·stənt]
The multiplicative constant for a term proportional to the metric in Einstein's equation relating the curvature of space to the energy-momentum tensor.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Mainstream cosmologists mostly accept that Mach's principle has been realized in the general relativity via the cosmological principle and, primarily, by the cosmological constant [LAMBDA], which can be treated as the universal impelling energy density of the vacuum, generating anew an inflationary expansion of the universe.
Einstein rejected the cosmological constant for two reasons:
with a fixed [LAMBDA] < 0, where we choose [LAMBDA] to be the cosmological constant of the Kerr-AdS space-time.
And the value of the cosmological constant (Eq.) tends to zero as x tends to infinity.
Although this model is asymptotically anti-de Sitter, by assuming a small-enough cosmological constant, the manifold is sufficiently close to flat in the vicinity of the blackplane for this prescription to be valid.
Einstein's Field equation with cosmological constant [lambda] is given by
Lord Kelvin (the age of the Earth), astronomer Fred Hoyle (the expansion of the universe), Linus Pauling (the nature of the DNA helix), and Albert Einstein (the cosmological constant) are here as well, all testament to the rewards of perseverance and the scientific method as Livio attempts "to correct the impression scientific breakthroughs are purely success stories."
The 60 papers examine such topics as cold compressed baryonic matter with hidden local symmetry and holography, topological and curvature effects in a multi-fermion interaction model, continuum superpartners from supersymmetric unparticles, new regularization in extra dimensional model and renormalization group flow of the cosmological constant, and critical behaviors of sigma-mode and pion in holographic superconductors.