{{Short description|Application of the theory of relativity to the universe as a whole}}
'''Einstein's static universe''', aka the '''Einstein universe''' or the '''Einstein static eternal universe''', is a relativistic model of the universe proposed by [[Albert Einstein]] in 1917.<ref>{{cite journal |last=Einstein |first=Albert |title=Kosmologische Betrachtungen zur allgemeinen Relativitätstheorie |lang=de |trans-title=Cosmological considerations on the general theory of relativity |journal=Sitzungs. König. Preuss. Akad. |date=1917 |pages=Sitzungsb. König. Preuss. Akad. 142–152}}</ref><ref>{{cite book|author1=Lorentz H.A. |author2=Einstein A. |author3=Minkowski H. |author4=H. Weyl |title=The Principle of Relativity|publisher=Metheun & Co.|location=New York|date = 1923|pages=175–188}}</ref> Shortly after completing the [[general theory of relativity]], Einstein applied his new theory of gravity to the universe as a whole. Assuming a universe that was static in time, and possessed of a uniform distribution of matter on the largest scales, Einstein was led to a finite, static universe of [[Closed universe|spherical]] [[spatial curvature]].
To achieve a consistent solution to the [[Einstein field equations]] for the case of a static universe with a non-zero density of matter, Einstein found it necessary to introduce a new term to the field equations, the [[cosmological constant]]. In the resulting model, the radius ''R'' and density of matter ''ρ'' of the universe were related to the cosmological constant Λ according to Λ = 1/''R''<sup>2</sup> = ''κρ''/2, where ''κ'' is the [[Einstein gravitational constant]].<ref>{{cite journal|last1=O'Raifeartaigh |display-authors=etal |title=Einstein's 1917 static model of the universe: a centennial review|journal=Eur. Phys. J. H|date=2017|volume=42|issue=3|pages=431–474|doi=10.1140/epjh/e2017-80002-5|arxiv=1701.07261|bibcode=2017EPJH...42..431O|s2cid=119461771 }}</ref>
Following the discovery by [[Edwin Hubble]] of a linear relation between the [[Redshift#Expansion of space|redshifts of the galaxies and their distance]] in 1929,<ref>{{cite journal|last1=Hubble|first1=Edwin|title=A relation between distance and radial velocity among extra-galactic nebulae|journal=Proceedings of the National Academy of Sciences|date=1929|volume=15|issue=3|pages=168–173|doi=10.1073/pnas.15.3.168|pmid=16577160|pmc=522427|bibcode=1929PNAS...15..168H|doi-access=free}}</ref> Einstein abandoned his static model of the universe and proposed expanding models such as the [[Friedmann–Einstein universe]] and the [[Einstein–de Sitter universe]]. In both cases, he set the cosmological constant to zero, declaring it "no longer necessary ... and theoretically unsatisfactory".<ref>{{cite journal|last1=Einstein|first1=Albert|title=Zum kosmologischen Problem der allgemeinen Relativitätstheorie|journal=Sitzungsb. König. Preuss. Akad.|date = 1931|pages=235–237}}</ref><ref>{{cite book|last1=Einstein|first1=Albert|title=Relativity: The Special and General Theories|date=1946|publisher=Metheun|location=New York|page=137|edition=16th}}</ref><ref>{{cite journal|last1=O'Raifeartaigh and McCann|title=Einstein's cosmic model of 1931 revisited: an analysis and translation of a forgotten model of the universe|journal=Eur. Phys. J. H|date=2014|volume=39|issue=1|pages=63–85|doi=10.1140/epjh/e2013-40038-x|arxiv=1312.2192|bibcode=2014EPJH...39...63O|s2cid=53419239}}</ref><ref>{{cite book|last1=Nussbaumer and Bieri|title=Discovering the Expanding Universe|date=2009|publisher=Cambridge University Press|location=Cambridge|pages=147}}</ref><ref>{{cite journal|author=A. S. Eddington |title=On the Instability of Einstein's Spherical World |journal=Monthly Notices of the Royal Astronomical Society |volume=90 |issue=7 |date=9 May 1930 |pages=668–678 |doi=10.1093/mnras/90.7.668 |doi-access=free}}</ref> In many Einstein biographies, it is claimed that Einstein referred to the cosmological constant in later years as his "biggest blunder". The astrophysicist [[Mario Livio]] has recently cast doubt on this claim, suggesting that it may be exaggerated.<ref>{{Cite news |url=https://www.nytimes.com/2013/06/09/books/review/brilliant-blunders-by-mario-livio.html |url-access=subscription |archive-url=https://web.archive.org/web/20130618190609/http://www.nytimes.com/2013/06/09/books/review/brilliant-blunders-by-mario-livio.html?pagewanted=all |archive-date=18 June 2013 |title=The Genius of Getting It Wrong: ''Brilliant Blunders'' by Mario Livio |date=9 June 2013 |newspaper=[[The New York Times]] |last=Zimmer |first1=Carl |author-link=Carl Zimmer}}{{cbignore}}</ref> ==See also== *[[Timeline of cosmological theories]] ==References== {{Reflist}} [[Category:General relativity]] [[Category:Albert Einstein]] [[Category:Physical cosmology]] {{relativity-stub}}