expanding universe

American  

noun

Astronomy.

1. 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.

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Etymology

Origin of expanding universe

First recorded in 1930–35

Example Sentences

See Examples For:

expanding universe

In an expanding universe, more distant galaxies generally recede more quickly because a greater amount of space lies between them and us.

From Science Daily ● Jul. 25, 2026

The theory began to take shape in the 1920s, when Georges Lemaître linked Edwin Hubble’s observations of receding galaxies with Alexander Friedmann’s earlier equations describing an expanding universe.

From The Wall Street Journal ● May 19, 2026

“In the quickly expanding universe of cases involving sanctions for the misuse of artificial intelligence, this case is a notorious outlier in both degree and volume,” Clarke wrote.

From Los Angeles Times ● Mar. 27, 2026

Belgian cosmologist and Catholic priest Georges Lemaitre made that connection by realizing that the theory of general relativity described an expanding universe.

From Salon ● Feb. 14, 2025

Penrose’s theorem had shown that any collapsing star must end in a singularity; the time-reversed argument showed that any Friedmann-like expanding universe must have begun with a singularity.

From "A Brief History of Time: And Other Essays" by Stephen Hawking