steady-state theory


steady-state theory
n.
a theory of cosmology, no longer favored, holding that new matter is continuously being created, thus keeping the density of the expanding universe constant: see BIG-BANG THEORY

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Concept of an expanding universe whose average density remains constant, matter being continuously created throughout it to form new stars and galaxies at the same rate that old ones recede from sight.

A steady-state universe has no beginning or end, and its average density and arrangement of galaxies are the same as seen from every point. Galaxies of all ages are intermingled. The theory was first put forward by William Macmillan (1861–1948) in the 1920s and modified by Fred Hoyle to deal with problems that had arisen in connection with the big-bang model. Much evidence obtained since the 1950s contradicts the steady-state theory and supports the big-bang model.

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      in cosmology, a view that the universe is always expanding but maintaining a constant average density, matter being continuously created to form new stars and galaxies at the same rate that old ones become unobservable as a consequence of their increasing distance and velocity of recession. A steady-state universe has no beginning or end in time; and from any point within it the view on the grand scale—i.e., the average density and arrangement of galaxies—is the same. Galaxies of all possible ages are intermingled.

      The theory was first put forward by Sir James Jeans (Jeans, Sir James) in about 1920 and again in revised form in 1948 by Hermann Bondi (Bondi, Sir Hermann) and Thomas Gold (Gold, Thomas). It was further developed by Sir Fred Hoyle (Hoyle, Sir Fred) to deal with problems that had arisen in connection with the alternative big-bang hypothesis. Observations since the 1950s have produced much evidence contradictory to the steady-state picture and supportive of the big-bang model (q.v.).

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Universalium. 2010.

Look at other dictionaries:

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  • steady-state theory — n. a theory of cosmology, no longer favored, holding that new matter is continuously being created, thus keeping the density of the expanding universe constant: see BIG BANG THEORY …   English World dictionary

  • steady state theory — steady state .theory n [singular] technical the idea that things in space have always existed and have always been moving away from each other as new atoms begin to exist →↑big bang theory …   Dictionary of contemporary English

  • Steady State theory — This article is about Cosmology. For other uses, see Steady state (disambiguation). Physical cosmology …   Wikipedia

  • steady state theory — noun (cosmology) the theory that the universe maintains a constant average density with matter created to fill the void left by galaxies that are receding from each other the steady state theory has been abandoned in favor of the big bang theory… …   Useful english dictionary

  • steady state theory — Astron. a theory in which the universe is assumed to have average properties that are constant in space and time so that new matter must be continuously and spontaneously created to maintain average densities as the universe expands. Also called… …   Universalium

  • steady state theory — noun the cosmological theory that the universe has always existed in a steady state and that the expansion of the universe is compensated by the continuous creation of matter as a property of space itself. Compare big bang theory …   Australian English dictionary

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  • steady state theory — noun Date: 1948 a theory in astronomy: the universe has always existed and has always been expanding with hydrogen being created continuously compare big bang theory …   New Collegiate Dictionary

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