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A non-standard cosmology is a cosmological framework that fundamentally contradicts one of the basic aspects of the big bang model of physical cosmology. These are:

1. that the universe is expanding,
2. that the universe emerged, in the past, from a hot, dense state
3. the cosmological principle, that the universe is roughly homogeneous and isotropic, and that we are not observing it from a preferred locale

This contrasts to cosmological models which differ from standard Lambda-CDM model, by modifying detailed features of it (such as the nature of dark energy) or by supplementing the Big Bang model with a first cause (like the cyclic model).

Non-standard versus standard

Non-standard cosmologies are usually not considered by physicists, because the essentials of the big bang theory have been confirmed by a wide enough range of complementary observations that they believe there is little chance of the theory being replaced in its essentials. A well known letter by advocates of non-standard cosmology has affirmed this: "today, virtually all financial and experimental resources in cosmology are devoted to big bang studies." Moreover, the astronomy and physics communities argue that non-standard cosmologies have not come close to reproducing the range of successes of the big bang model.

Halton Arp, one of the most famous of these astronomers, is an observational astronomer, as such his arguments do not constitute an alternative cosmological model; rather, he maintains that they are a refutation of the Big Bang, and invites theoretical astrophysicists to join him in working out alternative explanations.

Some ideas in non-standard cosmology, such as the steady-state theory of Hoyle, Gold and Bondi, the ambiplasma model of Alfvén and the tired light model of Zwicky are largely of historical interest, although they may retain a few supporters. While they were once considered serious competitors to the big bang model, the discovery of the cosmic microwave background radiation, and in particular its black-body spectrum, has led most physicists to reject them and conclude that the observational evidence now strongly favors the big bang.

Today, non-standard cosmologies are generally promoted by a few independent researchers and a larger number of amateurs who disagree with some of the basic tenets of the big bang model. Largely because of the disparate nature of their work, there is not a single non-standard cosmology. Within the category are many different ideas and models which frequently contradict each other.

Non-standard cosmologies are different from cosmologies which accept the basic tenets of the big bang cosmology, while modifying parts of the concordance ΛCDM model. Such theories include alternative models of dark energy, such as quintessence, phantom energy and some ideas in brane cosmology; alternative models of dark matter, such as modified Newtonian dynamics; alternatives or extensions to inflation such as chaotic inflation and the ekpyrotic model; and proposals to supplement the universe with a first cause, such as the Hartle-Hawking boundary condition, the cyclic model, and the string landscape. There is no consensus about these ideas amongst cosmologists, but they are nonetheless active fields of academic inquiry.

History

Since the discovery of the cosmic microwave background by Penzias and Robert Wilson in 1965, most cosmologists have concluded that observations are best explained by the big bang model. However, there have been two periods in which interest in non-standard cosmology has increased due to observational data which posed difficulties for the big bang. The first occurred was the late 1970s when there were a number of unsolved problems such as the horizon problem, the flatness problem, and the lack of magnetic monopoles challenged the big bang model. These issues were eventually resolved by cosmic inflation in the 1980s. This idea subsequently became part of the understanding of the big bang, although alternatives have been proposed from time to time. The second occurred in the mid-1990s when observations of the ages of globular clusters and the primordial helium abundance apparently disagreed with the big bang. However, by the late 1990s, most astronomers had concluded that these observations did not challenge the big bang and additional data from COBE and WMAP provided detailed quantitative measures which were consistent with standard cosmology.

In an Open Letter to the Scientific Community, signed by thirty-three non-standard cosmology supporters, including astronomer Hermann Bondi, and published in the May 22nd 2004 issue of the New Scientist periodical, they protest that the Big Bang theory has not been able to provide a basis for quantitative predictions. They also decry the lack of funding for the support of non-standard research.

In contrast to this, the overwhelming majority of cosmologists, astrophysicists and astronomers consider the Big Bang theory, exemplified by the concordance Lambda-CDM model, hugely successful. Also the 1990s gave a massive improvement to the precision of observational data, which continues to agree with the standard cosmology.

Non-standard cosmologies

There have been a number of non-standard models which have been proposed. Standard responses to some of the claims made in by the variable mass and plasma cosmology proposals are footnoted to the notes section at the end of the article.

Creationist ideas

Young Earth Creationists who for various reasons object to standard cosmology have offered a variety of alternatives that have ranged from the idea that the universe was created as according to Genesis with light from distant objects created in transit (Omphalism) to more involved critiques such as proposing a non-constant speed of light or a bounded universe that erupted from a white hole. Old Earth creationists do not object to the standard model of cosmology in astrophysics and are known to debate their fellow creationists over the issue. Both Young Earth Creationism and Old Earth Creationism have been considered by skeptical organizations and the scientific community to be pseudoscience, junk science, fringe science, or bad science.

Quasi-steady state

Although the original steady state model is now considered to be contrary to observations even by its originators, a modification of the steady state model has been proposed which envisions the universe as originating through many little bangs rather than one big bang. It supposes that the Universe goes through periodic expansion and contraction phases, with a soft "rebound" in place of the Big Bang. Thus the redshift is explained by the fact that the Universe is currently in an expansion phase.

The steady state and quasi-steady state theorists have proposed that the intergalactic medium contains microscopic iron dust particles or whiskers, which can scatter radio waves in such a manner as to produce an isotropic CMB. However, there is no observational evidence for the existence of these iron particles.

Tired light

The tired light effect was proposed by Fritz Zwicky in 1929 to explain the observed cosmological redshift. It has been found incompatible with the observed time dilation that is associated with the cosmological redshift.

A traditional explanation of this effect is dynamical friction of photons; the photons' gravitational interactions with stars and other material will progressively reduce their momentum, thus producing a redshift. However, this process will also tend to blur images of distant objects, and no such blurring has been detected .

Note that in the General Theory of Relativity, dynamical friction does not apply to photons (basically, because photons are massless). This does not contradict the conservation laws, because in the general theory they apply only locally, and dynamical friction is inherently non-local.

Variable mass hypothesis and intrinsic redshifts

There remain small numbers of astrophysicists, including Jayant Narlikar, Y.P. Varshni and Halton Arp, who argue that redshifts in galaxies do not correlate with distance and/or are not due to general relativistic effects arising from a universal expansion, and that this invalidates the need for the Big Bang.

Halton Arp, one of the most famous of these astronomers, is an observational astronomer, as such his arguments do not constitute an alternative cosmological model; rather, he maintains that they are a refutation of the Big Bang, and invites theoretical astrophysicists to join him in working out alternative explanations. Observations made by himself and his team from as far back as 1960. The controversy is an amalgamated holdover from the history of quasar observations and steady state theories. Before the redshifts of the objects were determined, Arp argued that the Eddington luminosity set limits on how distant the quasars could be. Because he was also a detractor of the Big Bang, Arp used his observational skills to try to refute the expansion of the universe. When most other scientists accepted the inability of alternatives to explain the observations that the Big Bang explained, Arp kept to his guns. From the 1970s onward, Arp has made observations of correlations between quasars (and more recently, X-ray sources from Chandra data) and (relatively) nearby AGN (Active Galactic Nuclei) which he claims demonstrates that quasar redshifts are not entirely due to the expansion of the universe, but contain a local, or non-cosmological, component. Arp claims that clusters of quasars have been observed around many galaxies which all have some properties in common:

• The active galaxy always has a lower redshift than any of its associated quasars.
• The quasars tend to lie within a narrow conical zone centered about the minor (rotational) axis of the associated active galaxy.
• Schematically, the quasars' redshifts are inversely proportional to their angular distances from the AGN, i.e. as apparent distance from the AGN increases, the redshift of the quasars decrease.
• Some of the quasars occur as pairs on either side of an AGN, particularly the X-ray sources appearing in the Chandra data.

These observations indicate to Arp that a relationship may exist between quasars (or at least a certain type of quasar) and AGN that is completely unrelated to the standard explanation that quasars are AGN at cosmological distances. Arp claims that certain quasars originate as very high redshift objects ejected from the nuclei of active galaxies, and gradually lose their non-cosmological redshift component as they evolve into galaxies. This stands in stark contradiction to most accepted models of galaxy formation.

The biggest problem with Arp's analysis is that today there are tens of thousands of quasars with known redshifts discovered by various sky surveys. The vast majority of these quasars are not correlated in any way with nearby AGN. Indeed, with improved observing techniques, a number of host galaxies have been observed around quasars which indicates that those quasars at least really are at cosmological distances and are not the kind of objects Arp proposes. Arp's analysis, according to most scientists, suffers from being based on small number statistics and hunting for peculiar coincidences and odd associations. In a vast universe such as our own, peculiarities and oddities are bound to appear if one looks in enough places. Unbiased samples of sources, taken from numerous galaxy surveys of the sky show none of the proposed 'irregularities' nor any statistically significant correlations exist.

In addition, it is not clear what mechanism would be responsible for intrinsic redshifts, or its supposed gradual dissipation over time. It is also unclear how nearby quasars would explain some features in the spectrum of quasars which the standard model easily explains. In the standard cosmology, the clouds of neutral hydrogen between the quasar and the earth at different redshifts spikes between the quasar redshift and the rest frequency of Lyman alpha in a feature known as the Lyman-alpha forest. Moreover, in extreme quasars one can observe the absorbion of neutral hydrogen which has not yet been reionized in a feature known as the Gunn-Peterson trough. Most cosmologists see this missing theoretical work as sufficient reason to explain the observations as either chance or error.

Halton Arp attributes his observations to the "variable-mass hypothesis", which has its foundations within the frame of Machian physics. The variable-mass theory invokes constant matter creation from active galactic nuclei, which puts it into the class of steady-state theory.

A consequence of Arp's proposed AGN-origin of quasars would be that quasars would be much closer, much larger, and much less luminous than currently supposed and their heavy element composition would no longer require primaeval Population III stars. Such a theory would predict that the heavy element composition of quasars would be similar to their associated AGN, though observed metal lines in quasars are notoriously weaker than nearby AGN. Variable luminosity and absorption phenomena such as the Lyman-alpha forest would both be explained by as yet theoretically undeveloped "local means".

Plasma cosmology

Plasma cosmology is a classic non-standard model developed by Hannes Alfvén, based on laboratory research into plasmas, and applied to cosmological observations. Plasma cosmology has much in common with the steady state theory. In particular, both include the Strong Cosmological Principle which includes an assumption that the universe is isotropic in time as well as in space. One difference between plasma cosmology and steady-state is that plasma cosmology does not invoke matter creation; rather it hypothesises a flow of matter between different areas of the universe. In some versions of plasma cosmology, matter is explicitly assumed to have always existed, or at least that it formed at a time so far in the past as to be forever beyond our empirical methods of investigation.

Some plasma cosmologists account for the observed galaxy rotation curves by supposing the existence of additional electro-magnetic forces and interactions. They claim that by treating the arms of galaxies as plasma filaments interacting with electromagnetic fields, the filamentary structure of galaxy clusters and superclusters can be viewed as a result of the self-amplifying nature of currents in plasmas. In this way, plasma cosmology purports to explain two observations often attributed in the standard cosmological models as due to dark matter. However, proponents of the Big Bang theory claim that no non-standard cosmology explains in detail the totality of proposed evidence for dark matter.

Alfvén, Lerner and others working within plasma cosmology have claimed that the temperature, isotropy, and non-polarisation of the CMB can be readily explained as the diffusion of galactic radio emission by the magnetic fields of intervening plasma filaments. Electrons travelling along the large, weak magnetic field lines of a galaxy can absorb radio, and re-emit it in a different direction. This scatters the radiation, much as light from the sun is scattered in a dense fog. This can also explain the observed decrease in radio brightness of galaxies relative to their IR luminosity with increasing redshift. Lerner explains that radiation from distant galaxies successively interacts with the magnetic fields of many intervening galaxies, nebulae, supernova remnants and so on, resulting in an isotropic scatter. However, standard cosmologists have been able to model in detail not only these global features, but also the detailed measurements of anisotropies and polarization of the CMB, and have identified a number of features such as peaks and valleys in its power spectrum which correspond to cosmological quantities.

With regards to anisotropy studies, the WMAP experiment has been especially fruitful in providing a goldmine of data that is interpreted easily by the standard cosmological models. The inability thus far of plasma cosmologies to come up with a theory that replicates these features in detail remains a major hurdle for the models to overcome.

Self creation cosmology

Self creation cosmology (SCC) theories are an adaptation of the Brans-Dicke theory in which the requirement of the conservation of energy-momentum is relaxed to allow the scalar field to interact with matter and create mass.

The original SCC paper (Barber, G.A. : 1982, Gen Relativ Gravit. 14, 117. 'On Two Self Creation Cosmologies') explored two toy theories of which the first was rejected on the grounds of a gross violation of the equivalence principle, and the second was an early version of the new 2002 theory.

Although the field equations of the new 2002 SCC theory are manifestly covariant, energy is locally conserved in a preferred foliation of space-time that is selected by Mach's principle .

The new theory is conformally equivalent to canonical GR in vacuo so that test particles follow the geodesics of GR in solar system experiments. This degeneracy, in which the present tests of GR are equal with those of SCC, may be resolved by three further definitive experiments in which the predictions differ. One of them, the Gravity Probe B geodetic precession, is being evaluated in 2006; SCC predicts 2/3 that of the GR N-S precession, i.e. 4.4096 arcsec/yr.

In its cosmological solution, in which the theory does differ from canonical GR, SCC does not require unknown dark energy, or exotic dark matter, to be concordant with present cosmological constraints. In particular, as an example of a freely coasting model , in which the universe expands strictly linearly with time , SCC clears basic constraints on nucleosynthesis.

In the Jordan conformal frame of the theory the cosmological solution is closed, static, eternal and singularity free. In this frame rulers 'shrink' and atomic clocks 'speed up' as their atoms exponentially gain mass with cosmological time .

Philosophical problems associated with 'an origin' thus disappear.

Finally, SCC predicts a cosmological 'clock-slip' between atomic clock time and ephemeris time. Consequentially, distant spacecraft should appear to suffer a sunwards acceleration equal to cH, as indeed seems to be observed in the Pioneer anomaly.

Nucleosynthesis objections to non-standard cosmologies

One of the major successes of the Big Bang theory has been to provide a prediction that corresponds to the observations of the abundance of light elements in the universe. Along with the explanation provided for the Hubble law and for the Cosmic microwave background, this observation has proved very difficult for alternative theories to explain.

Theories which assert that the universe has an infinite age, including many of the theories described above, fail to account for the abundance of deuterium in the cosmos, because deuterium easily undergoes nuclear fusion in stars and there are no known astrophysical processes other than the Big Bang itself that can produce it in large quantities. Hence the fact that deuterium is not an extremely rare component of the universe suggests that the universe has a finite age.

Theories which assert that the universe has a finite life but that the Big Bang did not happen have problems with the abundance of helium-4. The observed amount of He is far larger than the amount that should have been created via stars or any other known process. By contrast, the abundance of He in Big Bang models is very insensitive to assumptions about baryon density, changing only a few percent as the baryon density changes by several orders of magnitude. The observed value of He appears to be within the range calculated.

Notes

1. ^ An Open Letter to the Scientific Community
2. As quasars are considered by most astronomers to be highly luminous, distant cores of AGN, it isn't surprising that the AGN whose galaxy is more easily observable would have a lower redshift.
3. Some astrophysicists believe that gravitational lensing might be responsible for some examples of quasars in the immediate vicinity of AGN, but Arp and others argue that gravitational lensing cannot account for the quasars' tendency to align along the host galaxies minor axis.
4. It has been pointed out that it is impossible for this relationship to continue indefinitely. It is a purely observational coincidence in the minds of the vast majority of astrophysicists.
5. The question of whether quasars are cosmological or not was an active controversy in the late 1960s and early 1970s, but by the late 1970s most astronomers had considered the issue settled. The main argument against cosmological distances for quasars was that the energy required was far too high to be explainable by nuclear fusion, but this objection was removed by the proposal of gravity powered accretion disks.
6. Arp and others who agree with him have been known to support the argument for a varying non-cosmological redshift by referring to a so-called "magnitude-redshift discrepancy". When a Hubble Law-type plot of quasar magnitudes versus redshift is made, a graph with a diffuse scatter and no clear linear relation is generated. However, since absolute magnitudes can only be independently calibrated to an upper limit using size constraints from variability and an Eddington luminosity, it is likely that quasars are exhibiting differing luminosities that cannot necessarily be derived from such simplistic first principles. Arp, Burbidge, and others maintain that the scatter in these plots further supports the idea that quasars have a non-cosmological component to their redshift, but nearly everyone else in the field accepts that quasars have variable luminosity.
7. The first instance of observing the host galaxies around quasars was announced in 1983 by Gehren as published in the Proceedings of the Twenty-fourth Liege International Astrophysical Colloquium. p. 489-493.
8. For a description of mainstream cosmology's view of Arp's suggestions in this regard see Jones, H. What makes an astronomical controversy? Astronomy Now Vol. 19, No. 3, p. 58 - 61 (2005).
9. While it is true that in astrophysics plasma and magnetic effects are considered very important in determining the structure of gas and dust within a galaxy, it is unclear by what mechanism magnetic fields would change galaxy rotation curves and velocity dispersions. Galaxy velocity dispersion measurements come in part from observations of halo stars and it is unclear how a magnetic field would change the orbital motion of a star in an area where there is very little gas and dust.
10. The structure of the filaments seen in cosmological galaxy surveys are very different from the structure of filaments seen in most plasma processes, and there is no proposed mechanism offered by the alternative model as to why the size of the structures has an upper-limit.
11. Lerner fails to explain why the electrons should reemit in the best measured blackbody spectrum observed in all of science and how the entire plasma can become thermalized with exposure to anisotropic radiation fields.
12. There was recently some excitement on the part of certain plasma cosmology adherents over an analysis of WMAP results by researchers at the University of Durham. This analysis purported to show certain variations of microkelvin anisotropies in the WMAP data corresponding to the locations of local galactic clusters and superclusters. Fans of Eric Lerner claim that his model predicted similar types of associations. However, this association was predicted in the Big Bang model to be due to the Sunyaev-Zel'dovich effect, and the investigation was designed with that in mind.

See also

• General: Cosmology, List of astronomical topics

Creation: Creative evolution, Creation myths, Creationism, modern geocentrism

Other: Anthropic principle, Dirac large numbers hypothesis, De Sitter universe

Bibliography

• Arp, Halton, "Seeing Red". Apeiron, Montreal. August 1998. ISBN 0968368905
• Hannes, Alfvén D., "Cosmic Plasma". Reidel Pub Co., February 1981. ISBN 9027711518
• Hoyle, Fred, and Geoffrey Burbidge, and Jayant V. Narlikar, "A Different Approach to Cosmology : From a Static Universe through the Big Bang towards Reality". Cambridge University Press. February 17, 2000. ISBN 0521662230
• Lerner. Eric J., "Big Bang Never Happened", Vintage Books, October 1992. ISBN 067974049X
• Mitchell, William C., "Bye Bye Big Bang: Hello Reality". Cosmic Sense Books. January 2002. ISBN 0964318814
• Narlikar, Jayant Vishnu, "Introduction to Cosmology". Jones & Bartlett Pub. January 1983. IUCAA. ISBN 0867200154
• Peratt, Anthony L., "Physics of the Plasma Universe". Springer-Verlag, 1991, ISBN 0387975756

External links and references

• Burbidge, G., Quasi-Steady State Cosmology. University of California, San Diego. Center for Astrophysics and Space Sciences and Department of Physics La Jolla, CA.
• Kane, Gordon L., "Perspectives on Issues Beyond the Standard Model". (ArXiv)
• Klempner, Geoffrey, "The ten big questions. Big Bang Theory"
• Lerner, E. J. "Radio absorption by the intergalactic medium." ApJ 361 (1990), 63-68.
• Lopez-Corredoira, Martin, Observational Cosmology: caveats and open questions in the standard model. Astronomisches Institut der Universität Basel.
• Marmet, Paul, "Big Bang Cosmology Meets an Astronomical Death".
• Narlikar, Jayant V. and T. Padmanabhan, "Standard Cosmology and Alternatives: A Critical Appraisal". Annual Review of Astronomy and Astrophysics, Vol. 39, p. 211-248 (2001).
• Narlikar, Vishwakarma, and Burbidge, "quasi-steady state model".
• Rosania, Gustavo, "AntiBigBang.com Come Discover The New Cosmology"!
• Rourke, Colin, "A new paradigm for the universe (preliminary version)"
• Setterfield, B. and Dzimano, D. THE REDSHIFT AND THE ZERO POINT ENERGY (on CDK)
• Shanks, T., "Problems with the Current Cosmological Paradigm". Astrophysics, astro-ph/0401409. University of Durham, England.
• Tifft, W. G. Evidence for Quantization and Variable Redshifts in the Cosmic Background Rest Frame. Steward Observatory, University of Arizona, Tucson, Arizona
• Wright, Edward L. "Cosmological Fads and Fallacies:" Errors in some popular attacks on the Big Bang
• What Is Dark Energy argues that dark energy demonstrates the big bang theory is flawed
• Open Directory Project: Cosmology
• Barber, G.A. , 1982, Gen Relativ Gravit. 14, 117. 'On Two Self Creation Cosmologies'
• Barber, G.A., Astrophysics and Space Science, (2002) 282,4 pgs 683-730. "A New Self Creation Cosmology.
• Barber, G.A. , "Self Creation Cosmology - An Alternative Gravitational Theory, one chapter of 'Horizons in World Physics, Volume 247: New Developments in Quantum Cosmology Research', Nova Science Publishers, Inc. New York. Also (ArXiv).

• Cosmology
• Pseudophysics