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expanding universe

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noun Astronomy.

a concept or representation of the universe, based on the observed redshifts of distant galaxies, in which the galaxies are assumed to be receding from each other at a speed proportional to their separation as a result of the expansion of the universe.
See also big bang theory, Hubble's constant, cosmological redshift.

Origin of expanding universe

First recorded in 1930–35
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019