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

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

In other words, we're trying to find out the speed limit of the expanding universe, but some measurements have given us different answers.

From Salon • Dec. 9, 2024

As a crosscheck, an initial Webb observation in 2023 confirmed that Hubble measurements of the expanding universe were accurate.

From Science Daily • Mar. 11, 2024

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