Plasma cosmology

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Hannes Alfvén suggested that, by scaling laboratory results by a factor of 10⁹, he could extrapolate magnetospheric conditions. Another scaling jump of 10⁹ was required extrapolate to galactic conditions, and a third jump of 10⁹ was required to extrapolate to the Hubble distance. ^[1]

Plasma cosmology is a non-standard cosmology^[2] originally proposed by Hannes Alfvén in the 1960s that attempts to explain the development of the visible universe through the combined effects of gravity and electromagnetic forces inherent to astrophysical plasma. Alfvén developed his cosmological ideas based on scaling of observations from terrestrial laboratories and in situ space physics experiments to cosmological scales orders-of-magnitude greater.^[1] His most famous cosmological proposal was that the universe was an equal mixture of ionized matter and anti-matter in the form of so-called ambiplasma that would naturally separate as annihilation reactions occurred accompanied by a tremendous release of energy.^{[citation needed]}

Plasma cosmology contradicts the current consensus of astrophysicists that Einstein's Theory of general relativity explains the origin and evolution of the universe on its largest scales, relying instead on the further development of classical mechanics and classical electrodynamics as applied to astrophysical plasmas. While in the late 1980s to early 1990s there was limited discussion over the merits of plasma cosmology, today advocates for these ideas are generally ignored by the professional cosmology community.^[3][4]

[edit] Cosmic plasma

Main article: astrophysical plasma

Hannes Alfvén devoted much of his professional career attempting to characterize plasmas for which he was awarded the Nobel Prize in Physics in 1970. However, while plasma physics is uncontroversially accepted to play an important role in many astrophysical phenomena due in part to plasma's ubiquity, Alfvén held to a few ideas which have not been accepted by the scientific consensus. Chief among these is the assertion that electromagnetic forces are equal in importance with gravitation on the largest scales.^[5] However, Alfvén came to this conclusion by simply extrapolating plasma phenomena from small scales to large scales without providing any workable mathematical models demonstrating predictions to account for distant observations, such as redshift, SN1 data, etc.^{[citation needed]} and hence, his theories have been for the most part dismissed as philosophical beliefs with no sound basis in science.^{[citation needed] [1]} While magnetic fields are considered of interest to modern astrophysics in many standard smaller-scale astrophysical structure formation models with magnetic braking speeding gravitational collapse by transferring angular momentum from the contracting objects, standard large-scale structure models do not normally consider the magnetic field large enough to aid in angular momentum transfer for virializing processes in clusters.^[6] Research in these issues is ongoing, but plasma processes are not considered in theoretical modeling to play a signifcant role in structure or galaxy formation.^[7]

Some of the more provocative proposals of Alfvén included qualitative explanations for star formation using Birkeland currents.^[8] These plasma currents were held by Alfvén and his supporters to be responsible for many filamentary structures seen in astrophysical observations. However, there remains no direct observational evidence of such large scale plasma currents and mainstream astrophysical explanations for large-scale phenomena do not include plasma current mechanisms.^{[citation needed]}

[edit] Alfvén and Klein cosmologies

Hannes Alfvén (1908-1995), winning the Nobel Prize for his work on magnetohydrodynamics [8].

The conceptual origins of plasma cosmology were developed in 1965 by Alfvén in his book Worlds-Antiworlds, basing some of his work on Oskar Klein's earlier proposal that astrophysical plasmas played an important role in galaxy formation. In 1971, Klein would extend Alfvén's proposals and develop the "Alfvén-Klein model" of cosmology. Their cosmology relied on giant astrophysical explosions resulting from a hypothetical mixing of cosmic matter and antimatter that created the universe or meta-galaxy as they preferred to speculate (see the Shapley-Curtis debate for more on the history of distinguishing between the universe and the Milky Way galaxy). This hypothetical substance that spawned the universe was termed "ambiplasma" and took the forms of proton-antiprotons (heavy ambiplasma) and electrons-positrons (light ambiplasma). In Alfvén's cosmology, the universe contained heavy symmetric ambiplasma with protective light ambiplasma, separated by double layers. According to Alfvén, such an ambiplasma would be relatively long-lived as the component particles and antiparticles would be too hot and too low-density to annihilate with each other rapidly. Annihilation radiation would emanate from the double layers of plasma and antiplasma domains. The exploding double layer was also suggested by Alfvén as a possible mechanism for the generation of cosmic rays^{[citation needed]}, x-ray bursts and gamma-ray bursts.^[9]

Ambiplasma was proposed in part to explain the observed baryon asymmetry in the universe as being due to an initial condition of exact symmetry between matter and antimatter.^[10] According to Alfvén and Klein, ambiplasma would naturally form pockets of matter and pockets of antimatter that would expand outwards as annihilation between matter and antimatter occurred at the boundaries. Therefore, they concluded that we must happen to live in one of the pockets that was mostly baryons rather than antibaryons. The processes governing the evolution and characteristics of the universe at its largest scale would be governed mostly by this feature.

Alfvén postulated that the universe has always existed^[11] due to causality arguments and rejection of ex nihilo models as a stealth form of creationism.^[12] The cellular regions of exclusively matter or antimatter would appear to expand in regions local to annihilation, which Alfvén considered as a possible explanation for the observed apparent expansion of the universe as merely a local phase of a much larger history.

[edit] Further developments

While plasma cosmology has never had the support of most astronomers or physicists, researchers have continued to promote and develop the approach, and publish in the special issues of the IEEE Transactions on Plasma Science that are co-edited by plasma cosmology proponent Anthony Peratt.^[13] A few papers regarding plasma cosmology were published in other mainstream journals until the 1990s. Additionally, in 1991, Eric J. Lerner, an independent researcher in plasma physics and nuclear fusion, wrote a popular-level book supporting plasma cosmology called The Big Bang Never Happened. At that time there was renewed interest in the subject among the cosmological community (along with other non-standard cosmologies). This was due to anomalous results reported in 1987 by Andrew Lange and Paul Richardson of UC Berkeley and Toshio Matsumoto of Nagoya University that indicated the cosmic microwave background might not have a blackbody spectrum. However, the final announcement (in April 1992) of COBE satellite data corrected the earlier contradiction of the Big Bang; the level of interest in plasma cosmology has since fallen such that little research is now conducted.

[edit] Comparison to mainstream cosmology

Physical Cosmology

Physical Cosmology

Universe · Big Bang Age of the universe Timeline of the Big Bang... Ultimate fate of the Universe

Early universe

Inflation · Nucleosynthesis Cosmic microwave background

Expanding universe

Redshift · Hubble's law Metric expansion of space Friedmann equations · FLRW metric

Structure formation

Shape of the universe Structure formation Galaxy formation Large-scale structure

Components

Lambda-CDM model Dark energy · Dark matter

History

Timeline of cosmology...

Cosmology experiments

Observational cosmology 2dF · SDSS CoBE · BOOMERanG · WMAP

Scientists

Einstein · Lemaître · Friedman Hubble · Penzias · Wilson Gamow · Dicke · Zel'dovich Mather · Smoot · others

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From a theoretical point of view, there remain a number of problems with the plasma cosmology model. The model is not formulated to the point where it is possible to perform numerical simulations similar to those now routinely performed to model the behaviour of early galaxies in the standard cosmology and which are used to predict the correlation function of the universe. The standard hierarchical models of galaxy and structure formation rely on dark matter collecting into the superclusters, clusters, and galaxies seen in the universe today. The size and nature of structure are based on an initial condition from the primordial anisotropies seen in the power spectrum of the cosmic microwave background.^[14] Recent simulations show agreement between observations of galaxy surveys and N-body cosmological simulations of the Lambda-CDM model.^[15] Most astrophysicists accept dark matter as a real phenomenon and a vital ingredient in structure formation, which cannot be explained by appeal to electromagnetic processes. The mass estimates of galaxy clusters using gravitational lensing also indicate that there is a large quantity of dark matter present, an observation not explained by plasma cosmology models.^[16]

Mainstream studies also suggest that the universe is homogeneous on large scales without evidence of the very large scale structure required by plasma filamentation proposals.^[17] The largest galaxy number count to date, the Sloan Digital Sky Survey, corresponds well to the mainstream picture.^[18]

Light element production without Big Bang nucleosynthesis (as required in plasma cosmology) has been discussed in the mainstream literature and was determined to produce excessive x-rays and gamma rays beyond that observed.^[19][20] This issue has not been completely addressed by plasma cosmology proponents in their proposals.^[21] Additionally, from an observational point of view, the gamma rays emitted by even small amounts of matter/antimatter annihilation should be easily visible using gamma ray telescopes. However, such gamma rays have not been observed. This could be resolved by proposing, as Alfvén did, that the bubble of matter we are in is larger than the observable universe. In order to test such a model, some signature of the ambiplasma would have to be looked for in current observations, and this requires that the model be formalized to the point where detailed quantitative predictions can be made. This has not been accomplished.

Although no plasma cosmology proposal explaining the cosmic microwave background radiation has been published since COBE results were announced, explanations relying on integrated starlight do not provide any indication of how to explain the observed angular power spectrum of one part in 10⁵ CMB anisotropies. The sensitivity and resolution of the measurement of these anisotropies was greatly advanced by WMAP and was subsequently heralded as a major confirmation of the Big Bang to the detriment of alternatives.^[22] These measurements showed the "acoustic peaks" were fit with high accuracy by the predictions of the Big Bang model and conditions of the early universe.

Plasma cosmology is not considered by the astronomical community to be a viable alternative to the Big Bang, and even its advocates agree the explanations it provides for phenomena are less detailed than those of conventional cosmology. As such, plasma cosmology has remained sidelined and viewed in the community as a proposal unworthy of serious consideration.

[edit] References