Cosmological Constant

cosmological constant

Term reluctantly added by Albert Einstein to his equations of general relativity in order to obtain a solution to the equations that described a static universe, as he believed it to be at the time. The constant has the effect of a repulsive force that acts against the gravitational attraction of matter in the universe. When Einstein heard of the evidence that the universe is expanding, he called the introduction of the cosmological constant the “biggest blunder” of his life. Recent developments suggest that in the early universe there may well have been a cosmological constant with a nonzero value.

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cosmological constant [¦käz·mə¦läj·ə·kəl ′kän·stənt]

(relativity)

The multiplicative constant for a term proportional to the metric in Einstein's equation relating the curvature of space to the energy-momentum tensor.

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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).

REFERENCE

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

G. I. NAAN