Friedmann–Einstein universe: Difference between revisions
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'''The Friedmann-Einstein universe''' is a model of the universe published by [[Albert Einstein]] in 1931.<ref>{{cite journal|last1=Einstein|first1=Albert|title=Zum kosmologischen Problem der allgemeinen Relativitätstheorie|journal=Sitzungs. König. Preuss. Akad.|date=1931|pages=235–237}}</ref> The model is of historic significance because it constituted the first scientific publication in which Einstein embraced the possibility of a cosmos of time-varying radius. Interpreting [[Edwin Hubble]]'s discovery of a linear relation between the redshifts of the galaxies and their radial distance<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 Science|date=1929|volume=15|pages=168-173}}</ref> as evidence for an expanding universe, Einstein abandoned his earlier static model of the universe and embraced the dynamic cosmology of [[Alexander Friedmann]]. Removing the [[cosmological constant]] term from the [[Friedmann equations]] on the grounds that it was both unsatisfactory and unnecessary, Einstein arrived at a model of the universe that expands and then contracts. |
'''The Friedmann-Einstein universe''' is a model of the universe published by [[Albert Einstein]] in 1931.<ref>{{cite journal|last1=Einstein|first1=Albert|title=Zum kosmologischen Problem der allgemeinen Relativitätstheorie|journal=Sitzungs. König. Preuss. Akad.|date=1931|pages=235–237}}</ref> The model is of historic significance because it constituted the first scientific publication in which Einstein embraced the possibility of a cosmos of time-varying radius. Interpreting [[Edwin Hubble]]'s discovery of a linear relation between the redshifts of the galaxies and their radial distance<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 Science|date=1929|volume=15|pages=168-173}}</ref> as evidence for an expanding universe, Einstein abandoned his earlier static model of the universe and embraced the dynamic cosmology of [[Alexander Friedmann]]. Removing the [[cosmological constant]] term from the [[Friedmann equations]] on the grounds that it was both unsatisfactory and unnecessary, Einstein arrived at a model of the universe that expands and then contracts.<ref>{{cite book|last1=Nussbaumer and Bieri|title=Discovering the Expanding Universe|date=2009|publisher=Cambridge University Press|location=Cambridge|pages=147–148}}</ref> |
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<ref name="cor-2013">O’Raifeartaigh, C. and McCann, B. (2014) ‘Einstein’s cosmic model of 1931 revisited: an analysis and translation of a forgotten model of the universe’.Eur. Phys. J. (H) 39 (1), pp. 63–85. [http://arxiv.org/abs/1312.2192 Physics ArXiv preprint]</ref> |
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<ref>{{cite book|last1=Nussbaumer and Bieri|title=Discovering the Expanding Universe|date=2009|publisher=Cambridge University Press|location=Cambridge|pages=147–148}}</ref> |
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In the model, Einstein derived simple expressions relating the density of matter, the radius of the universe and the timespan of the expansion to the [[Hubble constant]]. With the use of the contemporaneous value of 500 km/s/Mpc for the Hubble constant, he calculated values of 10<sup>-26</sup> cm<sup>-3</sup>, 10<sup>8</sup> light-years and 10<sup>10</sup> years for the density of matter, the radius of the universe and the timespan of the expansion respectively. It has recently been demonstrated that these calculations contained a systematic error.<ref |
In the model, Einstein derived simple expressions relating the density of matter, the radius of the universe and the timespan of the expansion to the [[Hubble constant]]. With the use of the contemporaneous value of 500 km/s/Mpc for the Hubble constant, he calculated values of 10<sup>-26</sup> cm<sup>-3</sup>, 10<sup>8</sup> light-years and 10<sup>10</sup> years for the density of matter, the radius of the universe and the timespan of the expansion respectively. It has recently been demonstrated that these calculations contained a systematic error.<ref name="cor-2013"/> |
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Einstein chose the Friedmann-Einstein universe as the topic of his 2nd Rhodes lecture at Oxford University in 1931. A record of the lecture, [[Einstein's Blackboard]], can be viewed at the [[Museum of the History of Science, Oxford]].It has recently been pointed out that the numerical errors in Einstein's model can also be seen on [[Einstein's blackboard]]. |
Einstein chose the Friedmann-Einstein universe as the topic of his 2nd Rhodes lecture at Oxford University in 1931. A record of the lecture, [[Einstein's Blackboard]], can be viewed at the [[Museum of the History of Science, Oxford]].It has recently been pointed out<ref name="cor-2013"/> that the numerical errors in Einstein's model can also be seen on [[Einstein's blackboard]]. |
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Revision as of 19:40, 20 October 2016
The Friedmann-Einstein universe is a model of the universe published by Albert Einstein in 1931.[1] The model is of historic significance because it constituted the first scientific publication in which Einstein embraced the possibility of a cosmos of time-varying radius. Interpreting Edwin Hubble's discovery of a linear relation between the redshifts of the galaxies and their radial distance[2] as evidence for an expanding universe, Einstein abandoned his earlier static model of the universe and embraced the dynamic cosmology of Alexander Friedmann. Removing the cosmological constant term from the Friedmann equations on the grounds that it was both unsatisfactory and unnecessary, Einstein arrived at a model of the universe that expands and then contracts.[3] [4]
In the model, Einstein derived simple expressions relating the density of matter, the radius of the universe and the timespan of the expansion to the Hubble constant. With the use of the contemporaneous value of 500 km/s/Mpc for the Hubble constant, he calculated values of 10-26 cm-3, 108 light-years and 1010 years for the density of matter, the radius of the universe and the timespan of the expansion respectively. It has recently been demonstrated that these calculations contained a systematic error.[4]
Einstein chose the Friedmann-Einstein universe as the topic of his 2nd Rhodes lecture at Oxford University in 1931. A record of the lecture, Einstein's Blackboard, can be viewed at the Museum of the History of Science, Oxford.It has recently been pointed out[4] that the numerical errors in Einstein's model can also be seen on Einstein's blackboard.
References
- ^ Einstein, Albert (1931). "Zum kosmologischen Problem der allgemeinen Relativitätstheorie". Sitzungs. König. Preuss. Akad.: 235–237.
- ^ Hubble, Edwin (1929). "A relation between distance and radial velocity among extra-galactic nebulae". Proceedings of the National Academy of Science. 15: 168–173.
- ^ Nussbaumer and Bieri (2009). Discovering the Expanding Universe. Cambridge: Cambridge University Press. pp. 147–148.
- ^ a b c O’Raifeartaigh, C. and McCann, B. (2014) ‘Einstein’s cosmic model of 1931 revisited: an analysis and translation of a forgotten model of the universe’.Eur. Phys. J. (H) 39 (1), pp. 63–85. Physics ArXiv preprint