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The idea of a static universe is one which demands that space is not expanding nor contracting but rather is dynamically stable. Albert Einstein proposed such a model as his preferred cosmology by adding a cosmological constant to his equations of general relativity to counteract the dynamical effects of gravity which in a universe of matter would cause the universe to collapse. After the discovery by Edwin Hubble that there was a relationship between redshift and distance, Einstein declared this formulation to be his "biggest blunder".

Even after Hubble's observations, Fritz Zwicky proposed that a static universe could still be viable if there was an alternative explanation of redshift due to a mechanism that would cause light to lose energy as it traveled through space, a concept that would come to be known as "tired light". Subsequent cosmological observations have shown such a model to be an unviable alternative, leading most astrophysicists to conclude that the static universe is essentially falsified.

Einstein's universe

Einstein's proposal was a universe that followed the dust solution of Einstein's field equation for value of cosmological constant equal ${\displaystyle \Lambda _{E}=4\pi G\rho /c^{2}}$, where ${\displaystyle G}$ is Newtonian gravitational constant, ${\displaystyle \rho }$ is density of space, and ${\displaystyle c}$ is speed of light. Value ${\displaystyle \Lambda _{E}}$ is called "Einstein's value of cosmological constant" or alternatively "cosmological constant of Einstein's universe".

The radius of curvature of space of Einstein's universe, called "Einstein's radius", is equal to

${\displaystyle R_{E}=\Lambda _{E}^{-1/2}={c \over {\sqrt {4\pi G\rho }}}.}$

"Einstein's universe" is one of Friedmann's solutions of Einstein's field equation, for the value of cosmological constant ${\displaystyle \Lambda _{E}}$. This is the only stationary solution of all Friedmann's solutions and because it is stationary it is thought to be non physical by majority of astronomers. Those astronomers think that the universe is expanding because there is observed a phenomenon of Hubble redshift and it is interpreted by those astronomers as Doppler shift caused by galaxies moving away from our own Galaxy. Therefore it is thought that the real solution of Einstein's field equation can't be stationary.

A number of other values of cosmological constants has been proposed by various authors and the value zero was particularly popular before 1998. It was even assumed by many authors that placing a cosmological constant in Einstein's field equation was an error on part of Einstein and it was labelled "Einstein's biggest blunder" apparently by Einstein himself. The zero value of cosmological constant predicts a decelerating expansion of the universe. After 1998, when observations established beyond any reasonable doubt that the expansion of the universe seems to be accelerating, the value zero had to be given up and a quest for establishing a real value started and is still going on as of 2006.

Nonstandard cosmologies

A very small number of proponents of the static universe continue to promote nonstandard cosmologies in defiance of scientific consensus, though the term "static universe" has fallen somewhat out of favor since it is recognized by, for example, advocates of plasma cosmology that the universe is "dynamically evolving".

See also

• Steady state theory
• Milne model

References

1. In George Gamow's autobiography, My World Line (1970) he quotes Einstein: "Much later, when I was discussing cosmological problems with Einstein, he remarked that the introduction of the cosmological term was the biggest blunder of his life."

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