Steady-state model

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In cosmology, the steady state model is an alternative to the Big Bang theory of the evolution of the universe. In the steady state model, the density of matter in the expanding universe remains unchanged due to a continuous creation of matter, thus adhering to the perfect cosmological principle, a principle that asserts that the observable universe is basically the same at any time as well as at any place.

While the steady state model enjoyed some minority support in the scientific mainstream until the mid-20th century, it is now rejected by the vast majority of cosmologists, astrophysicists and astronomers, as the observational evidence points to a hot Big Bang cosmology with a finite age of the universe, which the steady state model does not predict.[1][2]


In the 13th century, Siger of Brabant authored the thesis The Eternity of the World, which argued that there was no first man, and no first specimen of any particular: the physical universe is thus without any first beginning, and therefore eternal. Siger's views were condemned by the pope in 1277.

Cosmological expansion was originally discovered through observations by Edwin Hubble. Theoretical calculations also showed that the static universe as modeled by Einstein (1917) was unstable. The modern Big Bang theory is one in which the universe has a finite age and has evolved over time through cooling, expansion, and the formation of structures through gravitational collapse.


It is now known that Albert Einstein considered a steady state model of the expanding universe, as indicated in a 1931 manuscript, many years before Hoyle, Bondi and Gold. However, he quickly abandoned the idea.[5]

Observational tests[edit]

Counts of radio sources[edit]


Cosmic microwave background[edit]

For most cosmologists, the definitive refutation of the steady state model came with the discovery of the cosmic microwave background radiation in 1964, which was predicted by the Big Bang theory. The steady state model explained microwave background radiation as the result of light from ancient stars that has been scattered by galactic dust. However, the cosmic microwave background level is very even in all directions, making it difficult to explain how it could be generated by numerous point sources and the microwave background radiation shows no evidence of characteristics such as polarization that are normally associated with scattering. Furthermore, its spectrum is so close to that of an ideal black body that it could hardly be formed by the superposition of contributions from a multitude of dust clumps at different temperatures as well as at different redshifts. Steven Weinberg wrote in 1972,

The steady state model does not appear to agree with the observed dL versus z relation or with source counts ... In a sense, this disagreement is a credit to the model; alone among all cosmologies, the steady state model makes such definite predictions that it can be disproved even with the limited observational evidence at our disposal. The steady state model is so attractive that many of its adherents still retain hope that the evidence against it will eventually disappear as observations improve. However, if the cosmic microwave radiation . . . is really black-body radiation, it will be difficult to doubt that the universe has evolved from a hotter denser early stage.[7]


Quasi-steady state[edit]

Quasi-steady state cosmology (QSS) was proposed in 1993 by Fred Hoyle, Geoffrey Burbidge, and Jayant V. Narlikar as a new incarnation of the steady state ideas meant to explain additional features unaccounted for in the initial proposal. The model suggests pockets of creation occurring over time within the universe, sometimes referred to as minibangs, mini-creation events, or little bangs.[8] After the observation of an accelerating universe, further modifications of the model were made.[9]

Astrophysicist and cosmologist Ned Wright has pointed out flaws in the model.[10] These first comments were soon rebutted by the proponents.[11] Wright and other mainstream cosmologists reviewing QSS have pointed out new flaws and discrepancies with observations left unexplained by proponents.[12]

Notes and citations[edit]

  5. ^ Castelvecchi, Davide (2014). "Einstein's lost theory uncovered". Nature. 506 (7489): 418–419. Bibcode:2014Natur.506..418C. doi:10.1038/506418a.
    Hoyle, F.; Burbidge, G.; Narlikar, J. V. (1994). "Astrophysical deductions from the quasi-steady state cosmology". Monthly Notices of the Royal Astronomical Society. 267 (4): 1007–1019. Bibcode:1994MNRAS.267.1007H. doi:10.1093/mnras/267.4.1007. hdl:11007/1133.
    Hoyle, F.; Burbidge, G.; Narlikar, J. V. (1994). "Astrophysical deductions from the quasi-steady state : Erratum". Monthly Notices of the Royal Astronomical Society. 269 (4): 1152. Bibcode:1994MNRAS.269.1152H. doi:10.1093/mnras/269.4.1152.
    Hoyle, F.; Burbidge, G.; Narlikar, J. V. (1995). "The basic theory underlying the quasi-steady state cosmological model". Proceedings of the Royal Society A. 448 (1933): 191. Bibcode:1995RSPSA.448..191H. doi:10.1098/rspa.1995.0012.
  9. ^ Narlikar, J. V.; Vishwakarma, R. G.; Burbidge, G. (2002). "Interpretations of the Accelerating Universe". Publications of the Astronomical Society of the Pacific. 114 (800): 1092–1096. arXiv:astro-ph/0205064. Bibcode:2002PASP..114.1092N. doi:10.1086/342374.
  10. ^ Wright, E. L. (1994). "Comments on the Quasi-Steady-State Cosmology". Monthly Notices of the Royal Astronomical Society. 276 (4): 1421. arXiv:astro-ph/9410070. Bibcode:1995MNRAS.276.1421W. doi:10.1093/mnras/276.4.1421.

Further reading[edit]