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Steady-state model

April 13, 2024

This article is about the cosmological theory. For other uses, see Steady state (disambiguation).

In cosmology, the steady-state model or steady state theory is an alternative to the Big Bang theory. 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 says that the observable universe is always the same at any time and any place.

In the Big Bang, the expanding Universe causes matter to dilute over time, while in the Steady-State Theory, continued matter creation ensures that the density remains constant over time.

From the 1940s to the 1960s, the astrophysical community was divided between supporters of the Big Bang theory and supporters of the steady-state theory. The steady-state model is now rejected by most cosmologists, astrophysicists, and astronomers. 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]

History edit

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 seen through observations by Edwin Hubble. Theoretical calculations also showed that the static universe, as modeled by Albert Einstein (1917), was unstable. The modern Big Bang theory, first advanced by Father Georges Lemaître, 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.

On the other hand, the steady-state model says while the universe is expanding, it nevertheless does not change its appearance over time (the perfect cosmological principle). E.g., the universe has no beginning and no end. This required that matter be continually created in order to keep the universe's density from decreasing. Influential papers on the topic of a steady-state cosmology were published by Hermann Bondi, Thomas Gold, and Fred Hoyle in 1948.[3][4] Similar models had been proposed earlier by William Duncan MacMillan, among others.[5]

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, Einstein abandoned the idea.[6]

Observational tests edit

Counts of radio sources edit

See also: Source counts

Problems with the steady-state model began to emerge in the 1950s and 60s – observations supported the idea that the universe was in fact changing. Bright radio sources (quasars and radio galaxies) were found only at large distances (therefore could have existed only in the distant past due to the effects of the speed of light on astronomy), not in closer galaxies. Whereas the Big Bang theory predicted as much, the steady-state model predicted that such objects would be found throughout the universe, including close to our own galaxy. By 1961, statistical tests based on radio-source surveys[7] had ruled out the steady-state model in the minds of most cosmologists, although some proponents of the steady state insisted that the radio data were suspect.[citation needed]

X-ray background edit

Gold and Hoyle (1959)[8] considered that matter that is newly created exists in a region that is denser than the average density of the universe. This matter then may radiate and cool faster than the surrounding regions, resulting in a pressure gradient. This gradient would push matter into an over-dense region and result in a thermal instability and emit a large amount of plasma. However, Gould and Burbidge (1963)[9] realized that the thermal bremsstrahlung radiation emitted by such a plasma would exceed the amount of observed X-rays. Therefore, in the steady-state cosmological model, thermal instability does not appear to be important in the formation of galaxy-sized masses.[10]

Cosmic microwave background edit

For most cosmologists, the 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."[11]

Since this discovery, the Big Bang theory has been considered to provide the best explanation of the origin of the universe. In most astrophysical publications, the Big Bang is implicitly accepted and is used as the basis of more complete theories.[citation needed]

Violations of the cosmological principle edit

Main articles: Cosmological principle and Perfect cosmological principle

One of the fundamental assumptions of the steady-state model is the cosmological principle, which follows from the perfect cosmological principle and which states that our observational location in the universe is not unusual or special; on a large-enough scale, the universe looks the same in all directions (isotropy) and from every location (homogeneity).[12] However, recent findings suggest that violations of the cosmological principle, especially of isotropy, exist, with some authors suggesting that the cosmological principle is now obsolete.[13][14][15][16]

Violations of isotropy edit

Evidence from galaxy clusters,[17][18] quasars,[19] and type Ia supernovae[20] suggest that isotropy is violated on large scales.

Data from the Planck Mission shows hemispheric bias in the cosmic microwave background (CMB) in two respects: one with respect to average temperature (i.e. temperature fluctuations), the second with respect to larger variations in the degree of perturbations (i.e. densities). The European Space Agency (the governing body of the Planck Mission) has concluded that these anisotropies in the CMB are, in fact, statistically significant and can no longer be ignored.[21]

Already in 1967, Dennis Sciama predicted that the CMB has a significant dipole anisotropy.[22][23] In recent years the CMB dipole has been tested and current results suggest our motion with respect to distant radio galaxies [24] and quasars [25] differs from our motion with respect to the CMB. The same conclusion has been reached in recent studies of the Hubble diagram of Type Ia supernovae[26] and quasars.[27] This contradicts the cosmological principle.

The CMB dipole is hinted at through a number of other observations. First, even within the CMB, there are curious directional alignments [28] and an anomalous parity asymmetry [29] that may have an origin in the CMB dipole.[30] Separately, the CMB dipole direction has emerged as a preferred direction in studies of alignments in quasar polarizations,[31] scaling relations in galaxy clusters,[32][33] strong lensing time delay,[14] Type Ia supernovae,[34] and quasars & gamma-ray bursts as standard candles.[35] The fact that all these independent observables, based on different physics, are tracking the CMB dipole direction suggests that the Universe is anisotropic in the direction of the CMB dipole.[citation needed]

Nevertheless, some authors have stated that the universe around Earth is isotropic at high significance by studies of the cosmic microwave background temperature maps.[36]

Violations of homogeneity edit

Many large-scale structures have been discovered, and some authors have reported some of the structures to be in conflict with the homogeneity condition required for the cosmological principle, including

Other authors claim that the existence of large-scale structures does not necessarily violate the cosmological principle.[40][13]

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.[41] After the observation of an accelerating universe, further modifications of the model were made.[42] The Planck particle is a hypothetical black hole whose Schwarzschild radius is approximately the same as its Compton wavelength; the evaporation of such a particle has been evoked as the source of light elements in an expanding steady-state universe.[43]

Astrophysicist and cosmologist Ned Wright has pointed out flaws in the model.[44] These first comments were soon rebutted by the proponents.[45] Wright and other mainstream cosmologists reviewing QSS have pointed out new flaws and discrepancies with observations left unexplained by proponents.[46]

See also edit

Notes and citations edit

  1. ^ "Steady State theory". BBC. Retrieved January 11, 2015. [T]he Steady State theorists' ideas are largely discredited today...
  2. ^ Kragh, Helge (1999). Cosmology and Controversy: The Historical Development of Two Theories of the Universe. Princeton University Press. ISBN 978-0-691-02623-7.
  3. ^ Bondi, Hermann; Gold, Thomas (1948). "The Steady-State Theory of the Expanding Universe". Monthly Notices of the Royal Astronomical Society. 108 (3): 252. Bibcode:1948MNRAS.108..252B. doi:10.1093/mnras/108.3.252.
  4. ^ Hoyle, Fred (1948). "A New Model for the Expanding Universe". Monthly Notices of the Royal Astronomical Society. 108 (5): 372. Bibcode:1948MNRAS.108..372H. doi:10.1093/mnras/108.5.372.
  5. ^ Kragh, Helge (2019). "Steady-State theory and the cosmological controversy". In Kragh, Helge (ed.). The Oxford handbook of the history of modern cosmology. pp. 161–205. doi:10.1093/oxfordhb/9780198817666.013.5. ISBN 978-0-19-881766-6. the Chicago astronomer William MacMillan not only assumed that stars and galaxies were distributed uniformly throughout infinite space, he also denied 'that the universe as a whole has ever been or ever will be essentially different from what it is today.'
  6. ^ Castelvecchi, Davide (2014). "Einstein's lost theory uncovered". Nature. 506 (7489): 418–419. Bibcode:2014Natur.506..418C. doi:10.1038/506418a. PMID 24572403.
  7. ^ Ryle and Clarke, "An examination of the steady-state model in the light of some recent observations of radio sources," MNRAW 122 (1961) 349
  8. ^ Gold, T.; Hoyle, F. (1 January 1959). "Cosmic rays and radio waves as manifestations of a hot universe". 9: 583. Bibcode:1959IAUS....9..583G. {{cite journal}}: Cite journal requires |journal= (help)
  9. ^ Gould, R. J.; Burbidge, G. R. (1 November 1963). "X-Rays from the Galactic Center, External Galaxies, and the Intergalactic Medium". The Astrophysical Journal. 138: 969. Bibcode:1963ApJ...138..969G. doi:10.1086/147698. ISSN 0004-637X.
  10. ^ Peebles, P. J. E. (2022). Cosmology's century: an inside history of our modern understanding of the universe. Princeton Oxford: Princeton University Press. ISBN 9780691196022.
  11. ^ Weinberg, Steven (1972). Gravitation and Cosmology. John Whitney & Sons. pp. 463–464. ISBN 978-0-471-92567-5.
  12. ^ Andrew Liddle. An Introduction to Modern Cosmology (2nd ed.). London: Wiley, 2003.
  13. ^ a b Elcio Abdalla; Guillermo Franco Abellán; et al. (11 Mar 2022), "Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies", Journal of High Energy Astrophysics, 34: 49, arXiv:2203.06142v1, Bibcode:2022JHEAp..34...49A, doi:10.1016/j.jheap.2022.04.002, S2CID 247411131
  14. ^ a b Krishnan, Chethan; Mohayaee, Roya; Colgáin, Eoin Ó; Sheikh-Jabbari, M. M.; Yin, Lu (16 September 2021). "Does Hubble Tension Signal a Breakdown in FLRW Cosmology?". Classical and Quantum Gravity. 38 (18): 184001. arXiv:2105.09790. Bibcode:2021CQGra..38r4001K. doi:10.1088/1361-6382/ac1a81. ISSN 0264-9381. S2CID 234790314.
  15. ^ Asta Heinesen; Hayley J. Macpherson (15 July 2021). "Luminosity distance and anisotropic sky-sampling at low redshifts: A numerical relativity study". Physical Review D. 104 (2): 023525. arXiv:2103.11918. Bibcode:2021PhRvD.104b3525M. doi:10.1103/PhysRevD.104.023525. S2CID 232307363. Retrieved 25 March 2022.
  16. ^ Jacques Colin; Roya Mohayaee; Mohamed Rameez; Subir Sarkar (20 November 2019). "Evidence for anisotropy of cosmic acceleration". Astronomy and Astrophysics. 631: L13. arXiv:1808.04597. Bibcode:2019A&A...631L..13C. doi:10.1051/0004-6361/201936373. S2CID 208175643. Retrieved 25 March 2022.
  17. ^ Lee Billings (April 15, 2020). "Do We Live in a Lopsided Universe?". Scientific American. Retrieved March 24, 2022.
  18. ^ Migkas, K.; Schellenberger, G.; Reiprich, T. H.; Pacaud, F.; Ramos-Ceja, M. E.; Lovisari, L. (8 April 2020). "Probing cosmic isotropy with a new X-ray galaxy cluster sample through the LX-T scaling relation". Astronomy & Astrophysics. 636 (April 2020): 42. arXiv:2004.03305. Bibcode:2020A&A...636A..15M. doi:10.1051/0004-6361/201936602. S2CID 215238834. Retrieved 24 March 2022.
  19. ^ Nathan J. Secrest; Sebastian von Hausegger; Mohamed Rameez; Roya Mohayaee; Subir Sarkar; Jacques Colin (February 25, 2021). "A Test of the Cosmological Principle with Quasars". The Astrophysical Journal Letters. 908 (2): L51. arXiv:2009.14826. Bibcode:2021ApJ...908L..51S. doi:10.3847/2041-8213/abdd40. S2CID 222066749.
  20. ^ B. Javanmardi; C. Porciani; P. Kroupa; J. Pflamm-Altenburg (August 27, 2015). "Probing the Isotropy of Cosmic Acceleration Traced By Type Ia Supernovae". The Astrophysical Journal Letters. 810 (1): 47. arXiv:1507.07560. Bibcode:2015ApJ...810...47J. doi:10.1088/0004-637X/810/1/47. S2CID 54958680. Retrieved March 24, 2022.
  21. ^ "Simple but challenging: the Universe according to Planck". ESA Science & Technology. October 5, 2016 [March 21, 2013]. Retrieved October 29, 2016.
  22. ^ Dennis Sciama (12 June 1967). "Peculiar Velocity of the Sun and the Cosmic Microwave Background". Physical Review Letters. 18 (24): 1065–1067. Bibcode:1967PhRvL..18.1065S. doi:10.1103/PhysRevLett.18.1065. Retrieved 25 March 2022.
  23. ^ G. F. R. Ellis; J. E. Baldwin (1 January 1984). "On the expected anisotropy of radio source counts". Monthly Notices of the Royal Astronomical Society. 206 (2): 377–381. doi:10.1093/mnras/206.2.377. Retrieved 25 March 2022.
  24. ^ Siewert, Thilo M.; Schmidt-Rubart, Matthias; Schwarz, Dominik J. (2021). "Cosmic radio dipole: Estimators and frequency dependence". Astronomy & Astrophysics. 653: A9. arXiv:2010.08366. Bibcode:2021A&A...653A...9S. doi:10.1051/0004-6361/202039840. S2CID 223953708.
  25. ^ Secrest, Nathan; von Hausegger, Sebastian; Rameez, Mohamed; Mohayaee, Roya; Sarkar, Subir; Colin, Jacques (25 February 2021). "A Test of the Cosmological Principle with Quasars". The Astrophysical Journal. 908 (2): L51. arXiv:2009.14826. Bibcode:2021ApJ...908L..51S. doi:10.3847/2041-8213/abdd40. ISSN 2041-8213. S2CID 222066749.
  26. ^ Singal, Ashok K. (2022). "Peculiar motion of Solar system from the Hubble diagram of supernovae Ia and its implications for cosmology". Monthly Notices of the Royal Astronomical Society. 515 (4): 5969–5980. arXiv:2106.11968. doi:10.1093/mnras/stac1986.
  27. ^ Singal, Ashok K. (2022). "Solar system peculiar motion from the Hubble diagram of quasars and testing the cosmological principle". Monthly Notices of the Royal Astronomical Society. 511 (2): 1819–1829. arXiv:2107.09390. doi:10.1093/mnras/stac144.
  28. ^ de Oliveira-Costa, Angelica; Tegmark, Max; Zaldarriaga, Matias; Hamilton, Andrew (25 March 2004). "The significance of the largest scale CMB fluctuations in WMAP". Physical Review D. 69 (6): 063516. arXiv:astro-ph/0307282. Bibcode:2004PhRvD..69f3516D. doi:10.1103/PhysRevD.69.063516. ISSN 1550-7998. S2CID 119463060.
  29. ^ Land, Kate; Magueijo, Joao (28 November 2005). "Is the Universe odd?". Physical Review D. 72 (10): 101302. arXiv:astro-ph/0507289. Bibcode:2005PhRvD..72j1302L. doi:10.1103/PhysRevD.72.101302. ISSN 1550-7998. S2CID 119333704.
  30. ^ Kim, Jaiseung; Naselsky, Pavel (10 May 2010). "Anomalous parity asymmetry of the Wilkinson Microwave Anisotropy Probe power spectrum data at low multipoles". The Astrophysical Journal. 714 (2): L265–L267. arXiv:1001.4613. Bibcode:2010ApJ...714L.265K. doi:10.1088/2041-8205/714/2/L265. ISSN 2041-8205. S2CID 24389919.
  31. ^ Hutsemekers, D.; Cabanac, R.; Lamy, H.; Sluse, D. (October 2005). "Mapping extreme-scale alignments of quasar polarization vectors". Astronomy & Astrophysics. 441 (3): 915–930. arXiv:astro-ph/0507274. Bibcode:2005A&A...441..915H. doi:10.1051/0004-6361:20053337. ISSN 0004-6361. S2CID 14626666.
  32. ^ Migkas, K.; Schellenberger, G.; Reiprich, T. H.; Pacaud, F.; Ramos-Ceja, M. E.; Lovisari, L. (April 2020). "Probing cosmic isotropy with a new X-ray galaxy cluster sample through the   scaling relation". Astronomy & Astrophysics. 636: A15. arXiv:2004.03305. Bibcode:2020A&A...636A..15M. doi:10.1051/0004-6361/201936602. ISSN 0004-6361. S2CID 215238834.
  33. ^ Migkas, K.; Pacaud, F.; Schellenberger, G.; Erler, J.; Nguyen-Dang, N. T.; Reiprich, T. H.; Ramos-Ceja, M. E.; Lovisari, L. (May 2021). "Cosmological implications of the anisotropy of ten galaxy cluster scaling relations". Astronomy & Astrophysics. 649: A151. arXiv:2103.13904. Bibcode:2021A&A...649A.151M. doi:10.1051/0004-6361/202140296. ISSN 0004-6361. S2CID 232352604.
  34. ^ Krishnan, Chethan; Mohayaee, Roya; Colgáin, Eoin Ó; Sheikh-Jabbari, M. M.; Yin, Lu (2022). "Hints of FLRW breakdown from supernovae". Physical Review D. 105 (6): 063514. arXiv:2106.02532. Bibcode:2022PhRvD.105f3514K. doi:10.1103/PhysRevD.105.063514. S2CID 235352881.
  35. ^ Luongo, Orlando; Muccino, Marco; Colgáin, Eoin Ó; Sheikh-Jabbari, M. M.; Yin, Lu (2022). "Larger H0 values in the CMB dipole direction". Physical Review D. 105 (10): 103510. arXiv:2108.13228. Bibcode:2022PhRvD.105j3510L. doi:10.1103/PhysRevD.105.103510. S2CID 248713777.
  36. ^ Saadeh D, Feeney SM, Pontzen A, Peiris HV, McEwen, JD (2016). "How Isotropic is the Universe?". Physical Review Letters. 117 (13): 131302. arXiv:1605.07178. Bibcode:2016PhRvL.117m1302S. doi:10.1103/PhysRevLett.117.131302. PMID 27715088. S2CID 453412.
  37. ^ Gott, J. Richard III; et al. (May 2005). "A Map of the Universe". The Astrophysical Journal. 624 (2): 463–484. arXiv:astro-ph/0310571. Bibcode:2005ApJ...624..463G. doi:10.1086/428890. S2CID 9654355.
  38. ^ Horvath, I.; Hakkila, J.; Bagoly, Z. (2013). "The largest structure of the Universe, defined by Gamma-Ray Bursts". arXiv:1311.1104 [astro-ph.CO].
  39. ^ "Line of galaxies is so big it breaks our understanding of the universe".
  40. ^ Nadathur, Seshadri (2013). "Seeing patterns in noise: gigaparsec-scale 'structures' that do not violate homogeneity". Monthly Notices of the Royal Astronomical Society. 434 (1): 398–406. arXiv:1306.1700. Bibcode:2013MNRAS.434..398N. doi:10.1093/mnras/stt1028. S2CID 119220579.
  41. ^ Hoyle, F.; Burbidge, G.; Narlikar, J. V. (1993). "A quasi-steady state cosmological model with creation of matter". The Astrophysical Journal. 410: 437–457. Bibcode:1993ApJ...410..437H. doi:10.1086/172761.
    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. (1994). "Further astrophysical quantities expected in a quasi-steady state Universe". Astronomy and Astrophysics. 289 (3): 729–739. Bibcode:1994A&A...289..729H.
    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. S2CID 53449963.
  42. ^ 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. S2CID 15456774.
  43. ^ Hoyle, F. (1993). "Light element synthesis in Planck fireballs". Astrophysics and Space Science. 198 (2): 177–193. doi:10.1007/BF00644753. S2CID 121245869.
  44. ^ 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. S2CID 118904109.
  45. ^ Hoyle, F.; Burbidge, G.; Narlikar, J. V. (1994). "Note on a Comment by Edward L. Wright". arXiv:astro-ph/9412045.
  46. ^ Wright, E. L. (20 December 2010). "Errors in the Steady State and Quasi-SS Models". UCLA, Physics & Astronomy Department.

Further reading edit

April 13, 2024
steady, state, model, this, article, about, cosmological, theory, other, uses, steady, state, disambiguation, cosmology, steady, state, model, steady, state, theory, alternative, bang, theory, steady, state, model, density, matter, expanding, universe, remains. This article is about the cosmological theory For other uses see Steady state disambiguation In cosmology the steady state model or steady state theory is an alternative to the Big Bang theory 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 says that the observable universe is always the same at any time and any place In the Big Bang the expanding Universe causes matter to dilute over time while in the Steady State Theory continued matter creation ensures that the density remains constant over time From the 1940s to the 1960s the astrophysical community was divided between supporters of the Big Bang theory and supporters of the steady state theory The steady state model is now rejected by most cosmologists astrophysicists and astronomers 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 Contents 1 History 2 Observational tests 2 1 Counts of radio sources 2 2 X ray background 2 3 Cosmic microwave background 2 4 Violations of the cosmological principle 2 4 1 Violations of isotropy 2 4 2 Violations of homogeneity 3 Quasi steady state 4 See also 5 Notes and citations 6 Further readingHistory editIn 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 seen through observations by Edwin Hubble Theoretical calculations also showed that the static universe as modeled by Albert Einstein 1917 was unstable The modern Big Bang theory first advanced by Father Georges Lemaitre 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 On the other hand the steady state model says while the universe is expanding it nevertheless does not change its appearance over time the perfect cosmological principle E g the universe has no beginning and no end This required that matter be continually created in order to keep the universe s density from decreasing Influential papers on the topic of a steady state cosmology were published by Hermann Bondi Thomas Gold and Fred Hoyle in 1948 3 4 Similar models had been proposed earlier by William Duncan MacMillan among others 5 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 Einstein abandoned the idea 6 Observational tests editCounts of radio sources edit See also Source counts Problems with the steady state model began to emerge in the 1950s and 60s observations supported the idea that the universe was in fact changing Bright radio sources quasars and radio galaxies were found only at large distances therefore could have existed only in the distant past due to the effects of the speed of light on astronomy not in closer galaxies Whereas the Big Bang theory predicted as much the steady state model predicted that such objects would be found throughout the universe including close to our own galaxy By 1961 statistical tests based on radio source surveys 7 had ruled out the steady state model in the minds of most cosmologists although some proponents of the steady state insisted that the radio data were suspect citation needed X ray background edit Gold and Hoyle 1959 8 considered that matter that is newly created exists in a region that is denser than the average density of the universe This matter then may radiate and cool faster than the surrounding regions resulting in a pressure gradient This gradient would push matter into an over dense region and result in a thermal instability and emit a large amount of plasma However Gould and Burbidge 1963 9 realized that the thermal bremsstrahlung radiation emitted by such a plasma would exceed the amount of observed X rays Therefore in the steady state cosmological model thermal instability does not appear to be important in the formation of galaxy sized masses 10 Cosmic microwave background edit For most cosmologists the 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 11 Since this discovery the Big Bang theory has been considered to provide the best explanation of the origin of the universe In most astrophysical publications the Big Bang is implicitly accepted and is used as the basis of more complete theories citation needed Violations of the cosmological principle edit Main articles Cosmological principle and Perfect cosmological principle One of the fundamental assumptions of the steady state model is the cosmological principle which follows from the perfect cosmological principle and which states that our observational location in the universe is not unusual or special on a large enough scale the universe looks the same in all directions isotropy and from every location homogeneity 12 However recent findings suggest that violations of the cosmological principle especially of isotropy exist with some authors suggesting that the cosmological principle is now obsolete 13 14 15 16 Violations of isotropy edit Evidence from galaxy clusters 17 18 quasars 19 and type Ia supernovae 20 suggest that isotropy is violated on large scales Data from the Planck Mission shows hemispheric bias in the cosmic microwave background CMB in two respects one with respect to average temperature i e temperature fluctuations the second with respect to larger variations in the degree of perturbations i e densities The European Space Agency the governing body of the Planck Mission has concluded that these anisotropies in the CMB are in fact statistically significant and can no longer be ignored 21 Already in 1967 Dennis Sciama predicted that the CMB has a significant dipole anisotropy 22 23 In recent years the CMB dipole has been tested and current results suggest our motion with respect to distant radio galaxies 24 and quasars 25 differs from our motion with respect to the CMB The same conclusion has been reached in recent studies of the Hubble diagram of Type Ia supernovae 26 and quasars 27 This contradicts the cosmological principle The CMB dipole is hinted at through a number of other observations First even within the CMB there are curious directional alignments 28 and an anomalous parity asymmetry 29 that may have an origin in the CMB dipole 30 Separately the CMB dipole direction has emerged as a preferred direction in studies of alignments in quasar polarizations 31 scaling relations in galaxy clusters 32 33 strong lensing time delay 14 Type Ia supernovae 34 and quasars amp gamma ray bursts as standard candles 35 The fact that all these independent observables based on different physics are tracking the CMB dipole direction suggests that the Universe is anisotropic in the direction of the CMB dipole citation needed Nevertheless some authors have stated that the universe around Earth is isotropic at high significance by studies of the cosmic microwave background temperature maps 36 Violations of homogeneity edit Many large scale structures have been discovered and some authors have reported some of the structures to be in conflict with the homogeneity condition required for the cosmological principle including The Clowes Campusano LQG discovered in 1991 which has a length of 580 Mpc The Sloan Great Wall discovered in 2003 which has a length of 423 Mpc 37 U1 11 a large quasar group discovered in 2011 which has a length of 780 Mpc The Huge LQG discovered in 2012 which is three times longer than and twice as wide as is predicted possible according to LCDM The Hercules Corona Borealis Great Wall discovered in November 2013 which has a length of 2000 3000 Mpc more than seven times that of the SGW 38 The Giant Arc discovered in June 2021 which has a length of 1000 Mpc 39 Other authors claim that the existence of large scale structures does not necessarily violate the cosmological principle 40 13 Quasi steady state editQuasi 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 41 After the observation of an accelerating universe further modifications of the model were made 42 The Planck particle is a hypothetical black hole whose Schwarzschild radius is approximately the same as its Compton wavelength the evaporation of such a particle has been evoked as the source of light elements in an expanding steady state universe 43 Astrophysicist and cosmologist Ned Wright has pointed out flaws in the model 44 These first comments were soon rebutted by the proponents 45 Wright and other mainstream cosmologists reviewing QSS have pointed out new flaws and discrepancies with observations left unexplained by proponents 46 See also editNon standard cosmology Background independence Copernican principle End of Greatness Large scale structure of the cosmos Expansion of the universeNotes and citations edit Steady State theory BBC Retrieved January 11 2015 T he Steady State theorists ideas are largely discredited today Kragh Helge 1999 Cosmology and Controversy The Historical Development of Two Theories of the Universe Princeton University Press ISBN 978 0 691 02623 7 Bondi Hermann Gold Thomas 1948 The Steady State Theory of the Expanding Universe Monthly Notices of the Royal Astronomical Society 108 3 252 Bibcode 1948MNRAS 108 252B doi 10 1093 mnras 108 3 252 Hoyle Fred 1948 A New Model for the Expanding Universe Monthly Notices of the Royal Astronomical Society 108 5 372 Bibcode 1948MNRAS 108 372H doi 10 1093 mnras 108 5 372 Kragh Helge 2019 Steady State theory and the cosmological controversy In Kragh Helge ed The Oxford handbook of the history of modern cosmology pp 161 205 doi 10 1093 oxfordhb 9780198817666 013 5 ISBN 978 0 19 881766 6 the Chicago astronomer William MacMillan not only assumed that stars and galaxies were distributed uniformly throughout infinite space he also denied that the universe as a whole has ever been or ever will be essentially different from what it is today Castelvecchi Davide 2014 Einstein s lost theory uncovered Nature 506 7489 418 419 Bibcode 2014Natur 506 418C doi 10 1038 506418a PMID 24572403 Ryle and Clarke An examination of the steady state model in the light of some recent observations of radio sources MNRAW 122 1961 349 Gold T Hoyle F 1 January 1959 Cosmic rays and radio waves as manifestations of a hot universe 9 583 Bibcode 1959IAUS 9 583G a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help Gould R J Burbidge G R 1 November 1963 X Rays from the Galactic Center External Galaxies and the Intergalactic Medium The Astrophysical Journal 138 969 Bibcode 1963ApJ 138 969G doi 10 1086 147698 ISSN 0004 637X Peebles P J E 2022 Cosmology s century an inside history of our modern understanding of the universe Princeton Oxford Princeton University Press ISBN 9780691196022 Weinberg Steven 1972 Gravitation and Cosmology John Whitney amp Sons pp 463 464 ISBN 978 0 471 92567 5 Andrew Liddle An Introduction to Modern Cosmology 2nd ed London Wiley 2003 a b Elcio Abdalla Guillermo Franco Abellan et al 11 Mar 2022 Cosmology Intertwined A Review of the Particle Physics Astrophysics and Cosmology Associated with the Cosmological Tensions and Anomalies Journal of High Energy Astrophysics 34 49 arXiv 2203 06142v1 Bibcode 2022JHEAp 34 49A doi 10 1016 j jheap 2022 04 002 S2CID 247411131 a b Krishnan Chethan Mohayaee Roya Colgain Eoin o Sheikh Jabbari M M Yin Lu 16 September 2021 Does Hubble Tension Signal a Breakdown in FLRW Cosmology Classical and Quantum Gravity 38 18 184001 arXiv 2105 09790 Bibcode 2021CQGra 38r4001K doi 10 1088 1361 6382 ac1a81 ISSN 0264 9381 S2CID 234790314 Asta Heinesen Hayley J Macpherson 15 July 2021 Luminosity distance and anisotropic sky sampling at low redshifts A numerical relativity study Physical Review D 104 2 023525 arXiv 2103 11918 Bibcode 2021PhRvD 104b3525M doi 10 1103 PhysRevD 104 023525 S2CID 232307363 Retrieved 25 March 2022 Jacques Colin Roya Mohayaee Mohamed Rameez Subir Sarkar 20 November 2019 Evidence for anisotropy of cosmic acceleration Astronomy and Astrophysics 631 L13 arXiv 1808 04597 Bibcode 2019A amp A 631L 13C doi 10 1051 0004 6361 201936373 S2CID 208175643 Retrieved 25 March 2022 Lee Billings April 15 2020 Do We Live in a Lopsided Universe Scientific American Retrieved March 24 2022 Migkas K Schellenberger G Reiprich T H Pacaud F Ramos Ceja M E Lovisari L 8 April 2020 Probing cosmic isotropy with a new X ray galaxy cluster sample through the LX T scaling relation Astronomy amp Astrophysics 636 April 2020 42 arXiv 2004 03305 Bibcode 2020A amp A 636A 15M doi 10 1051 0004 6361 201936602 S2CID 215238834 Retrieved 24 March 2022 Nathan J Secrest Sebastian von Hausegger Mohamed Rameez Roya Mohayaee Subir Sarkar Jacques Colin February 25 2021 A Test of the Cosmological Principle with Quasars The Astrophysical Journal Letters 908 2 L51 arXiv 2009 14826 Bibcode 2021ApJ 908L 51S doi 10 3847 2041 8213 abdd40 S2CID 222066749 B Javanmardi C Porciani P Kroupa J Pflamm Altenburg August 27 2015 Probing the Isotropy of Cosmic Acceleration Traced By Type Ia Supernovae The Astrophysical Journal Letters 810 1 47 arXiv 1507 07560 Bibcode 2015ApJ 810 47J doi 10 1088 0004 637X 810 1 47 S2CID 54958680 Retrieved March 24 2022 Simple but challenging the Universe according to Planck ESA Science amp Technology October 5 2016 March 21 2013 Retrieved October 29 2016 Dennis Sciama 12 June 1967 Peculiar Velocity of the Sun and the Cosmic Microwave Background Physical Review Letters 18 24 1065 1067 Bibcode 1967PhRvL 18 1065S doi 10 1103 PhysRevLett 18 1065 Retrieved 25 March 2022 G F R Ellis J E Baldwin 1 January 1984 On the expected anisotropy of radio source counts Monthly Notices of the Royal Astronomical Society 206 2 377 381 doi 10 1093 mnras 206 2 377 Retrieved 25 March 2022 Siewert Thilo M Schmidt Rubart Matthias Schwarz Dominik J 2021 Cosmic radio dipole Estimators and frequency dependence Astronomy amp Astrophysics 653 A9 arXiv 2010 08366 Bibcode 2021A amp A 653A 9S doi 10 1051 0004 6361 202039840 S2CID 223953708 Secrest Nathan von Hausegger Sebastian Rameez Mohamed Mohayaee Roya Sarkar Subir Colin Jacques 25 February 2021 A Test of the Cosmological Principle with Quasars The Astrophysical Journal 908 2 L51 arXiv 2009 14826 Bibcode 2021ApJ 908L 51S doi 10 3847 2041 8213 abdd40 ISSN 2041 8213 S2CID 222066749 Singal Ashok K 2022 Peculiar motion of Solar system from the Hubble diagram of supernovae Ia and its implications for cosmology Monthly Notices of the Royal Astronomical Society 515 4 5969 5980 arXiv 2106 11968 doi 10 1093 mnras stac1986 Singal Ashok K 2022 Solar system peculiar motion from the Hubble diagram of quasars and testing the cosmological principle Monthly Notices of the Royal Astronomical Society 511 2 1819 1829 arXiv 2107 09390 doi 10 1093 mnras stac144 de Oliveira Costa Angelica Tegmark Max Zaldarriaga Matias Hamilton Andrew 25 March 2004 The significance of the largest scale CMB fluctuations in WMAP Physical Review D 69 6 063516 arXiv astro ph 0307282 Bibcode 2004PhRvD 69f3516D doi 10 1103 PhysRevD 69 063516 ISSN 1550 7998 S2CID 119463060 Land Kate Magueijo Joao 28 November 2005 Is the Universe odd Physical Review D 72 10 101302 arXiv astro ph 0507289 Bibcode 2005PhRvD 72j1302L doi 10 1103 PhysRevD 72 101302 ISSN 1550 7998 S2CID 119333704 Kim Jaiseung Naselsky Pavel 10 May 2010 Anomalous parity asymmetry of the Wilkinson Microwave Anisotropy Probe power spectrum data at low multipoles The Astrophysical Journal 714 2 L265 L267 arXiv 1001 4613 Bibcode 2010ApJ 714L 265K doi 10 1088 2041 8205 714 2 L265 ISSN 2041 8205 S2CID 24389919 Hutsemekers D Cabanac R Lamy H Sluse D October 2005 Mapping extreme scale alignments of quasar polarization vectors Astronomy amp Astrophysics 441 3 915 930 arXiv astro ph 0507274 Bibcode 2005A amp A 441 915H doi 10 1051 0004 6361 20053337 ISSN 0004 6361 S2CID 14626666 Migkas K Schellenberger G Reiprich T H Pacaud F Ramos Ceja M E Lovisari L April 2020 Probing cosmic isotropy with a new X ray galaxy cluster sample through the LX T displaystyle L text X T nbsp scaling relation Astronomy amp Astrophysics 636 A15 arXiv 2004 03305 Bibcode 2020A amp A 636A 15M doi 10 1051 0004 6361 201936602 ISSN 0004 6361 S2CID 215238834 Migkas K Pacaud F Schellenberger G Erler J Nguyen Dang N T Reiprich T H Ramos Ceja M E Lovisari L May 2021 Cosmological implications of the anisotropy of ten galaxy cluster scaling relations Astronomy amp Astrophysics 649 A151 arXiv 2103 13904 Bibcode 2021A amp A 649A 151M doi 10 1051 0004 6361 202140296 ISSN 0004 6361 S2CID 232352604 Krishnan Chethan Mohayaee Roya Colgain Eoin o Sheikh Jabbari M M Yin Lu 2022 Hints of FLRW breakdown from supernovae Physical Review D 105 6 063514 arXiv 2106 02532 Bibcode 2022PhRvD 105f3514K doi 10 1103 PhysRevD 105 063514 S2CID 235352881 Luongo Orlando Muccino Marco Colgain Eoin o Sheikh Jabbari M M Yin Lu 2022 Larger H0 values in the CMB dipole direction Physical Review D 105 10 103510 arXiv 2108 13228 Bibcode 2022PhRvD 105j3510L doi 10 1103 PhysRevD 105 103510 S2CID 248713777 Saadeh D Feeney SM Pontzen A Peiris HV McEwen JD 2016 How Isotropic is the Universe Physical Review Letters 117 13 131302 arXiv 1605 07178 Bibcode 2016PhRvL 117m1302S doi 10 1103 PhysRevLett 117 131302 PMID 27715088 S2CID 453412 Gott J Richard III et al May 2005 A Map of the Universe The Astrophysical Journal 624 2 463 484 arXiv astro ph 0310571 Bibcode 2005ApJ 624 463G doi 10 1086 428890 S2CID 9654355 Horvath I Hakkila J Bagoly Z 2013 The largest structure of the Universe defined by Gamma Ray Bursts arXiv 1311 1104 astro ph CO Line of galaxies is so big it breaks our understanding of the universe Nadathur Seshadri 2013 Seeing patterns in noise gigaparsec scale structures that do not violate homogeneity Monthly Notices of the Royal Astronomical Society 434 1 398 406 arXiv 1306 1700 Bibcode 2013MNRAS 434 398N doi 10 1093 mnras stt1028 S2CID 119220579 Hoyle F Burbidge G Narlikar J V 1993 A quasi steady state cosmological model with creation of matter The Astrophysical Journal 410 437 457 Bibcode 1993ApJ 410 437H doi 10 1086 172761 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 1994 Further astrophysical quantities expected in a quasi steady state Universe Astronomy and Astrophysics 289 3 729 739 Bibcode 1994A amp A 289 729H 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 S2CID 53449963 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 S2CID 15456774 Hoyle F 1993 Light element synthesis in Planck fireballs Astrophysics and Space Science 198 2 177 193 doi 10 1007 BF00644753 S2CID 121245869 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 S2CID 118904109 Hoyle F Burbidge G Narlikar J V 1994 Note on a Comment by Edward L Wright arXiv astro ph 9412045 Wright E L 20 December 2010 Errors in the Steady State and Quasi SS Models UCLA Physics amp Astronomy Department Further reading editBurbidge G Hoyle F The Origin of Helium and the Other Light Elements The Astrophysical Journal 509 L1 L3 10 December 1998 Hoyle F Burbidge G Narlikar J V 2000 A Different Approach to Cosmology Cambridge University Press ISBN 978 0 521 66223 9 Mitton S 2005 Conflict in the Cosmos Fred Hoyle s Life in Science Joseph Henry Press ISBN 978 0 309 09313 2 Mitton S 2005 Fred Hoyle A Life in Science Aurum Press ISBN 978 1 85410 961 3 Narlikar Jayant Burbidge Geoffrey 2008 Facts and Speculations in Cosmology Cambridge University Press ISBN 978 0 521 86504 3 Portals nbsp Physics nbsp Astronomy nbsp Stars nbsp Spaceflight nbsp Outer space nbsp Solar System Retrieved from https en wikipedia org w index php title Steady state model amp oldid 1214056292, wikipedia, wiki, book, books, library,

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