critical density

American  

[krit-i-kuhl den-si-tee] / ˈkrɪt ɪ kəl ˈdɛn sɪ ti /

noun

Physics.

1. the density of a pure element or compound at a critical point.

   If space has positive curvature, the actual density of matter must be larger than the critical density.

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critical density British  

noun

1. the density of matter that would be required to halt the expansion of the universe

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Etymology

Origin of critical density

First recorded in 1885–90

Example Sentences

A tipping point will occur when there is such a critical density of objects in orbit that one collision could set off a chain reaction and take those systems offline, the report says.

From Los Angeles Times

Mesh networks with a fixed range need a critical density of users and are most likely to provide widespread connectivity at crowded events such as a music festival, a soccer game or a large protest.

From Scientific American

If the actual density of the universe is less than the critical density, it is predicted that the universe will forever expand, as there isn’t enough matter to stop it.

From Salon

Indeed, scientists have been known to calculate the “critical density” of the universe, which is proportional to the square of the Hubble constant, a variable used in estimating the size, age and expansion rate of the universe.

From Salon

Yet if the density of the universe is more than the critical density, then that means it has enough mass to stop expanding, which is what the latest study using Planck data is suggesting.

From Salon