open universe

noun

Astronomy.

1. a model of the universe in which the universe expands forever because there is not enough mass to counteract the expansion by means of gravitational attraction.

open universe

1. Model of the universe in which the curvature of space is flat or curved away from itself, entailing that the size of the universe is infinite. According to this model, gravity between objects is not able to stop or reverse the expansion of the universe, thus objects continue to move farther and farther apart as space moves outward. An object moving in a straight line in an open universe would never return to its starting point. According to current cosmological theories, the universe is open if it is insufficiently dense. Such a universe will never end, but will eventually become very cold and dark because stars gradually lose all of their energy.

2. Compare closed universe See Note at big bang

open universe

1. If there is not enough matter in the universe to exert a strong enough gravitational force to stop the universal expansion associated with the big bang, the universe is said to be open. (Compare closed universe and flat universe.)

Word History and Origins

Origin of open universe¹

First recorded in 1975–80

Example Sentences

In a 1979 paper, “Time without end: Physics and biology in an open universe,” Dyson asserts that the universe has a point, a purpose, as long as it harbors intelligence.

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And yet something ineffable and meaningful remains, an unquenchable spirit, still in motion, drifting upward toward heaven, or the open universe, or the stars.

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This creates a flat, and open, universe.

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The difference between a closed and open universe is a bit like the difference between a stretched flat sheet and an inflated balloon, Melchiorri told Live Science.

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He wrote his 1979 paper “Time Without End: Physics and Biology in an Open Universe,” in response to Steven Weinberg’s infamous remark that “the more the universe seems comprehensible, the more it also seems pointless.”

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