Plasma cosmology

Last updated
Comparison of the evolution of the universe under Alfven-Klein cosmology and the Big Bang theory. Klein-Alfven cosmology.svg
Comparison of the evolution of the universe under Alfvén–Klein cosmology and the Big Bang theory.

Plasma cosmology is a non-standard cosmology whose central postulate is that the dynamics of ionized gases and plasmas play important, if not dominant, roles in the physics of the universe at interstellar and intergalactic scales. [2] [1] In contrast, the current observations and models of cosmologists and astrophysicists explain the formation, development, and evolution of large-scale structures as dominated by gravity (including its formulation in Albert Einstein's general theory of relativity).

Contents

The original form of the theory, Alfvén–Klein cosmology, was developed by Hannes Alfvén and Oskar Klein in the 1960s and 1970s, [3] and holds that matter and antimatter exist in equal quantities at very large scales, that the universe is eternal rather than bounded in time by the Big Bang, and that the expansion of the observable universe is caused by annihilation between matter and antimatter rather than a mechanism like cosmic inflation. [1]

Cosmologists and astrophysicists who have evaluated plasma cosmology reject it because it does not match the observations of astrophysical phenomena as well as the currently accepted Big Bang model. [4] Very few papers supporting plasma cosmology have appeared in the literature since the mid-1990s.

The term plasma universe is sometimes used as a synonym for plasma cosmology, [2] as an alternative description of the plasma in the universe. [1] Plasma cosmology is a distinct enterprise from proposals sometimes called the Electric Universe, [5] which, taking inspiration from Immanuel Velikovsky, [6] suggests that electric currents flow into stars and power them like light bulbs, [7] though proponents of each are known to be sympathetic to each other. [8]

Alfvén–Klein cosmology

Hannes Alfven suggested that scaling laboratory results can be extrapolated up to the scale of the universe. A scaling jump by a factor 10 was required to extrapolate to the magnetosphere, a second jump to extrapolate to galactic conditions, and a third jump to extrapolate to the Hubble distance. Cosmic-triple-jump.svg
Hannes Alfvén suggested that scaling laboratory results can be extrapolated up to the scale of the universe. A scaling jump by a factor 10 was required to extrapolate to the magnetosphere, a second jump to extrapolate to galactic conditions, and a third jump to extrapolate to the Hubble distance.

In the 1960s, the theory behind plasma cosmology was introduced by Alfvén, [10] a plasma expert who won the 1970 Nobel Prize in Physics for his work on magnetohydrodynamics. [11] He proposed the use of plasma scaling to extrapolate the results of laboratory experiments and plasma physics observations and scale them over many orders of magnitude up to the largest observable objects in the universe (see box [9] ). [12] In 1971, Oskar Klein, a Swedish theoretical physicist, extended the earlier proposals and developed the Alfvén–Klein model of the universe, [13] or "metagalaxy", an earlier term used to refer to the empirically accessible part of the universe, rather than the entire universe including parts beyond our particle horizon. [14] [11]

In this model, the universe is made up of equal amounts of matter and antimatter with the boundaries between the regions of matter and antimatter being delineated by cosmic electromagnetic fields formed by double layers, thin regions comprising two parallel layers with opposite electrical charge. Interaction between these boundary regions would generate radiation, and this would form the plasma. Alfvén introduced the term ambiplasma for a plasma made up of matter and antimatter and the double layers are thus formed of ambiplasma. 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 each other rapidly. The double layers will act to repel clouds of opposite type, but combine clouds of the same type, creating ever-larger regions of matter and antimatter. The idea of ambiplasma was developed further into the forms of heavy ambiplasma (protons-antiprotons) and light ambiplasma (electrons-positrons). [10]

Alfvén–Klein cosmology was proposed in part to explain the observed baryon asymmetry in the universe, starting from an initial condition of exact symmetry between matter and antimatter. 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 in the double layer at the boundaries. They concluded that we must just happen to live in one of the pockets that was mostly baryons rather than antibaryons, explaining the baryon asymmetry. The pockets, or bubbles, of matter or antimatter would expand because of annihilations at the boundaries, which Alfvén considered as a possible explanation for the observed expansion of the universe, which would be merely a local phase of a much larger history. Alfvén postulated that the universe has always existed [15] [16] due to causality arguments and the rejection of ex nihilo models, such as the Big Bang, as a stealth form of creationism. [17] [18] The exploding double layer was also suggested by Alfvén as a possible mechanism for the generation of cosmic rays, [19] X-ray bursts and gamma-ray bursts. [20]

In 1993, theoretical cosmologist Jim Peebles criticized Alfvén–Klein cosmology, writing that "there is no way that the results can be consistent with the isotropy of the cosmic microwave background radiation and X-ray backgrounds". [21] In his book he also showed that Alfvén's models do not predict Hubble's law, the abundance of light elements, or the existence of the cosmic microwave background. A further difficulty with the ambiplasma model is that matter–antimatter annihilation results in the production of high energy photons, which are not observed in the amounts predicted. While it is possible that the local "matter-dominated" cell is simply larger than the observable universe, this proposition does not lend itself to observational tests.

Plasma cosmology and the study of galaxies

Hannes Alfvén from the 1960s to 1980s argued that plasma played an important if not dominant role in the universe. He argued that electromagnetic forces are far more important than gravity when acting on interplanetary and interstellar charged particles. [22] He further hypothesized that they might promote the contraction of interstellar clouds and may even constitute the main mechanism for contraction, initiating star formation. [23] The current standard view is that magnetic fields can hinder collapse, that large-scale Birkeland currents have not been observed, and that the length scale for charge neutrality is predicted to be far smaller than the relevant cosmological scales. [24]

In the 1980s and 1990s, Alfvén and Anthony Peratt, a plasma physicist at Los Alamos National Laboratory, outlined a program they called the "plasma universe". [25] [26] [27] In plasma universe proposals, various plasma physics phenomena were associated with astrophysical observations and were used to explain contemporary mysteries and problems outstanding in astrophysics in the 1980s and 1990s. In various venues, Peratt profiled what he characterized as an alternative viewpoint to the mainstream models applied in astrophysics and cosmology. [26] [27] [28] [16]

For example, Peratt proposed that the mainstream approach to galactic dynamics which relied on gravitational modeling of stars and gas in galaxies with the addition of dark matter was overlooking a possibly major contribution from plasma physics. He mentions laboratory experiments of Winston H. Bostick in the 1950s that created plasma discharges that looked like galaxies. [29] [30] Perrat conducted computer simulations of colliding plasma clouds that he reported also mimicked the shape of galaxies. [31] Peratt proposed that galaxies formed due to plasma filaments joining in a z-pinch, the filaments starting 300,000 light years apart and carrying Birkeland currents of 1018 amperes. [32] [33] Peratt also reported simulations he did showing emerging jets of material from the central buffer region that he compared to quasars and active galactic nuclei occurring without supermassive black holes. Peratt proposed a sequence for galaxy evolution: "the transition of double radio galaxies to radioquasars to radioquiet QSO's to peculiar and Seyfert galaxies, finally ending in spiral galaxies". [34] He also reported that flat galaxy rotation curves were simulated without dark matter. [32] At the same time Eric Lerner, an independent plasma researcher and supporter of Peratt's ideas, proposed a plasma model for quasars based on a dense plasma focus. [35]

Comparison with mainstream astrophysics

Standard astronomical modeling and theories attempt to incorporate all known physics into descriptions and explanations of observed phenomena, with gravity playing a dominant role on the largest scales as well as in celestial mechanics and dynamics. To that end, both Keplerian orbits and Albert Einstein's General Theory of Relativity are generally used as the underlying frameworks for modeling astrophysical systems and structure formation, while high-energy astronomy and particle physics in cosmology additionally appeal to electromagnetic processes including plasma physics and radiative transfer to explain relatively small scale energetic processes observed in the x-rays and gamma rays. Due to overall charge neutrality, plasma physics does not provide for very long-range interactions in astrophysics even while much of the matter in the universe is plasma. [36] (See astrophysical plasma for more.)

Proponents of plasma cosmology claim electrodynamics is as important as gravity in explaining the structure of the universe, and speculate that it provides an alternative explanation for the evolution of galaxies [34] and the initial collapse of interstellar clouds. [23] In particular plasma cosmology is claimed to provide an alternative explanation for the flat rotation curves of spiral galaxies and to do away with the need for dark matter in galaxies and with the need for supermassive black holes in galaxy centres to power quasars and active galactic nuclei. [33] [34] However, theoretical analysis shows that "many scenarios for the generation of seed magnetic fields, which rely on the survival and sustainability of currents at early times [of the universe are disfavored]", [24] i.e. Birkeland currents of the magnitude needed (1018 amps over scales of megaparsecs) for galaxy formation do not exist. [37] Additionally, many of the issues that were mysterious in the 1980s and 1990s, including discrepancies relating to the cosmic microwave background and the nature of quasars, have been solved with more evidence that, in detail, provides a distance and time scale for the universe.

Some of the places where plasma cosmology supporters are most at odds with standard explanations include the need for their models to have light element production without Big Bang nucleosynthesis, which, in the context of Alfvén–Klein cosmology, has been shown to produce excessive X-rays and gamma rays beyond that observed. [38] [39] Plasma cosmology proponents have made further proposals to explain light element abundances, but the attendant issues have not been fully addressed. [40] In 1995 Eric Lerner published his alternative explanation for the cosmic microwave background radiation (CMBR). [41] He argued that his model explained the fidelity of the CMB spectrum to that of a black body and the low level of anisotropies found, even while the level of isotropy at 1:105 is not accounted for to that precision by any alternative models. Additionally, the sensitivity and resolution of the measurement of the CMB anisotropies was greatly advanced by WMAP and the Planck satellite and the statistics of the signal were so in line with the predictions of the Big Bang model, that the CMB has been heralded as a major confirmation of the Big Bang model to the detriment of alternatives. [42] The acoustic peaks in the early universe are fit with high accuracy by the predictions of the Big Bang model, and, to date, there has never been an attempt to explain the detailed spectrum of the anisotropies within the framework of plasma cosmology or any other alternative cosmological model.

References and notes

  1. 1 2 3 4 Alfven, H.O.G. (1990). "Cosmology in the plasma universe – an introductory exposition". IEEE Transactions on Plasma Science. 18: 5–10. Bibcode:1990ITPS...18....5A. doi:10.1109/27.45495.
  2. 1 2 Peratt, Anthony (February 1992). "Plasma Cosmology" (PDF). Sky & Telescope. 83 (2): 136–141. Retrieved 26 May 2012. recount: It was described as this in the February 1992 issue of Sky & Telescope ("Plasma Cosmology"), and by Anthony Peratt in the 1980s, who describes it as a "nonstandard picture". The ΛCDM model big bang picture is typically described as the "concordance model", "standard model" or "standard paradigm" of cosmology here [ permanent dead link ], and here.
  3. Parker, Barry (1993). "Plasma Cosmology". The Vindication of the Big Bang. Boston, MA: Springer. p. 325. doi:10.1007/978-1-4899-5980-5_15. ISBN   978-1-4899-5980-5.
  4. Parker 1993, pp. 335–336.
  5. Shermer, Michael (2015-10-01). "The Difference between Science and Pseudoscience". Scientific American . Retrieved 2022-03-28.
  6. Bridgman, William T., Stuart Robbins, and C. Alex Young. "Crank Astronomy As A Teaching Tool." American Astronomical Society Meeting Abstracts# 215. Vol. 215. 2010.
  7. Scoles, Sarah (18 February 2016). "The People Who Believe Electricity Rules the Universe". Motherboard, Tech by Vice. Vice. Retrieved 1 November 2022.
  8. "Hogan and Velikovsky". www.jerrypournelle.com. Retrieved 2023-08-24.
  9. 1 2 Alfvén, Hannes (1983). "On hierarchical cosmology". Astrophysics and Space Science. 89 (2): 313–324. Bibcode:1983Ap&SS..89..313A. doi:10.1007/bf00655984. S2CID   122396373.
  10. 1 2 H., Alfvén (1966). Worlds-antiworlds: antimatter in cosmology. Freeman.
  11. 1 2 Kragh, H.S. (1996). Cosmology and Controversy: The Historical Development of Two Theories of the Universe. Vol. 23. Princeton University Press. pp. 482–483. ISBN   978-0-691-00546-1.
  12. Alfven, H.O G (1987). "Plasma universe" (PDF). Physica Scripta. T18: 20–28. Bibcode:1987PhST...18...20A. doi:10.1088/0031-8949/1987/t18/002. S2CID   250828260.
  13. Klein, O. (1971). "Arguments concerning relativity and cosmology". Science. 171 (3969): 339–45. Bibcode:1971Sci...171..339K. doi:10.1126/science.171.3969.339. PMID   17808634. S2CID   22308581.
  14. Alfvén, H.; Falthammar, C.-G. (1963). Cosmic electrodynamics. Oxford: Clarendon Press.
  15. Alfvén, H. (1988). "Has the Universe an Origin? (Trita-EPP)" (PDF). p. 6.
  16. 1 2 Peratt, A.L. (1995). "Introduction to Plasma Astrophysics and Cosmology" (PDF). Astrophysics and Space Science. 227 (1–2): 3–11. Bibcode:1995Ap&SS.227....3P. doi:10.1007/bf00678062. ISBN   978-94-010-4181-2. S2CID   118452749.
  17. Alfvén, H. (1992). "Cosmology: Myth or Science?". IEEE Transactions on Plasma Science. 20 (6): 590–600. Bibcode:1992ITPS...20..590A. doi:10.1109/27.199498.
  18. Alfvén, H. (1984). "Cosmology - Myth or science?". Journal of Astrophysics and Astronomy. 5 (1): 79–98. Bibcode:1984JApA....5...79A. doi:10.1007/BF02714974. ISSN   0250-6335. S2CID   122751100.
  19. H., Alfvén (1981). Cosmic plasma. Taylor & Francis. pp. IV.10.3.2, 109. recount: "Double layers may also produce extremely high energies. This is known to take place in solar flares, where they generate solar cosmic rays up to 109 to 1010 eV."
  20. Alfvén, H. (1986). "Double layers and circuits in astrophysics". IEEE Transactions on Plasma Science. PS-14 (6): 779–793. Bibcode:1986ITPS...14..779A. doi:10.1109/TPS.1986.4316626. S2CID   11866813.
  21. Pebbles, P.J.E. (1993). Principles of Physical Cosmology. Princeton University Press. p. 207. ISBN   978-0-691-07428-3.
  22. H. Alfvén and C.-G. Falthammar, Cosmic electrodynamics(2nd edition, Clarendon press, Oxford, 1963). "The basic reason why electromagnetic phenomena are so important in cosmical physics is that there exist celestial magnetic fields which affect the motion of charged particles in space ... The strength of the interplanetary magnetic field is of the order of 10−4 gauss (10 nanoteslas), which gives the [ratio of the magnetic force to the force of gravity] ≈ 107. This illustrates the enormous importance of interplanetary and interstellar magnetic fields, compared with gravitation, as long as the matter is ionized." (p.2-3)
  23. 1 2 Alfvén, H.; Carlqvist, P. (1978). "Interstellar clouds and the formation of stars". Astrophysics and Space Science. 55 (2): 487–509. Bibcode:1978Ap&SS..55..487A. doi:10.1007/BF00642272. S2CID   122687137.
  24. 1 2 Siegel, E. R.; Fry, J. N. (Sep 2006). "Can Electric Charges and Currents Survive in an Inhomogeneous Universe?". arXiv: astro-ph/0609031 . Bibcode:2006astro.ph..9031S.{{cite journal}}: Cite journal requires |journal= (help)
  25. Alfvén, H. (1986). "Model of the Plasma Universe" (PDF). IEEE Transactions on Plasma Science. PS-14 (6): 629–638. Bibcode:1986ITPS...14..629A. doi:10.1109/tps.1986.4316614. S2CID   31617468.[ permanent dead link ]
  26. 1 2 A. L. Peratt, Plasma Cosmology: Part I, Interpretations of a Visible Universe, World & I, vol. 8, pp. 294–301, August 1989.
  27. 1 2 A. L. Peratt, Plasma Cosmology:Part II, The Universe is a Sea of Electrically Charged Particles, World & I, vol. 9, pp. 306–317, September 1989 .
  28. "A.L. Peratt, Plasma Cosmology, Sky & Tel. Feb. 1992" (PDF).
  29. A. Peratt (1986). "Evolution of the plasma universe. I – Double radio galaxies, quasars, and extragalactic jets" (PDF). IEEE Transactions on Plasma Science. PS-14 (6): 639–660. Bibcode:1986ITPS...14..639P. doi:10.1109/TPS.1986.4316615. ISSN   0093-3813. S2CID   30767626.
  30. Bostick, W. H. (1986). "What laboratory-produced plasma structures can contribute to the understanding of cosmic structures both large and small". IEEE Transactions on Plasma Science. PS-14 (6): 703–717. Bibcode:1986ITPS...14..703B. doi:10.1109/TPS.1986.4316621. S2CID   25575722.
  31. AL Peratt; J Green; D Nielson (20 June 1980). "Evolution of Colliding Plasmas". Physical Review Letters. 44 (26): 1767–1770. Bibcode:1980PhRvL..44.1767P. doi:10.1103/PhysRevLett.44.1767.
  32. 1 2 E. J. Lerner (1991). The Big Bang Never Happened. New York and Toronto: Random House. ISBN   978-0-8129-1853-3.
  33. 1 2 AL Peratt; J Green (1983). "On the Evolution of Interacting, Magnetized, Galactic Plasmas". Astrophysics and Space Science. 91 (1): 19–33. Bibcode:1983Ap&SS..91...19P. doi:10.1007/BF00650210. S2CID   121524786.
  34. 1 2 3 A. Peratt (1986). "Evolution of the Plasma Universe: II. The Formation of Systems of Galaxies" (PDF). IEEE Transactions on Plasma Science. PS-14 (6): 763–778. Bibcode:1986ITPS...14..763P. doi:10.1109/TPS.1986.4316625. ISSN   0093-3813. S2CID   25091690.
  35. E.J. Lerner (1986). "Magnetic Self‑Compression in Laboratory Plasma, Quasars and Radio Galaxies". Laser and Particle Beams. 4 part 2 (2): 193‑222. Bibcode:1986LPB.....4..193L. doi: 10.1017/S0263034600001750 .
  36. Frank, Juhan; Frank, Carlos; Frank, J. R.; King, A. R.; Raine, Derek J. (1985-04-18). Accretion Power in Astrophysics. CUP Archive. p. 25. ISBN   9780521245302.
  37. Colafrancesco, S.; Giordano, F. (2006). "The impact of magnetic field on the cluster M – T relation". Astronomy and Astrophysics. 454 (3): L131–134. arXiv: astro-ph/0701852 . Bibcode:2006A&A...454L.131C. doi:10.1051/0004-6361:20065404. S2CID   1477289. recount: "Numerical simulations have shown that the wide-scale magnetic fields in massive clusters produce variations of the cluster mass at the level of ~ 5 − 10% of their unmagnetized value ... Such variations are not expected to produce strong variations in the relative [mass-temperature] relation for massive clusters."
  38. Audouze, J.; Lindley, D.; Silk, J. (1985). "Big Bang Photosynthesis and Pregalactic Nucleosynthesis of Light Elements". Astrophysical Journal. 293: L53–L57. Bibcode:1985ApJ...293L..53A. doi:10.1086/184490.
  39. Epstein; et al. (1976). "The origin of deuterium". Nature. 263 (5574): 198–202. Bibcode:1976Natur.263..198E. doi:10.1038/263198a0. S2CID   4213710. point out that if proton fluxes with energies greater than 500 MeV were intense enough to produce the observed levels of deuterium, they would also produce about 1000 times more gamma rays than are observed.
  40. Ref. 10 in "Galactic Model of Element Formation" (Lerner, IEEE Transactions on Plasma Science Vol. 17, No. 2, April 1989 Archived 2006-12-29 at the Wayback Machine ) is J.Audouze and J.Silk, "Pregalactic Synthesis of Deuterium" in Proc. ESO Workshop on "Primordial Helium", 1983, pp. 71–75 Lerner includes a paragraph on "Gamma Rays from D Production" in which he claims that the expected gamma ray level is consistent with the observations. He cites neither Audouze nor Epstein in this context, and does not explain why his result contradicts theirs.
  41. Lerner, Eric (1995). "Intergalactic Radio Absorption and the COBE Data" (PDF). Astrophysics and Space Science. 227 (1–2): 61–81. Bibcode:1995Ap&SS.227...61L. doi:10.1007/bf00678067. S2CID   121500864. Archived from the original (PDF) on 2011-07-15. Retrieved 2012-05-30.
  42. Spergel, D. N.; et al. (2003). "(WMAP collaboration), "First year Wilkinson Microwave Anisotropy Probe (WMAP) observations: Determination of cosmological parameters". Astrophysical Journal Supplement Series. 148 (1): 175–194. arXiv: astro-ph/0302209 . Bibcode:2003ApJS..148..175S. doi:10.1086/377226. S2CID   10794058.

Further reading

Related Research Articles

<span class="mw-page-title-main">Antimatter</span> Material composed of antiparticles of the corresponding particles of ordinary matter

In modern physics, antimatter is defined as matter composed of the antiparticles of the corresponding particles in "ordinary" matter, and can be thought of as matter with reversed charge, parity, and time, known as CPT reversal. Antimatter occurs in natural processes like cosmic ray collisions and some types of radioactive decay, but only a tiny fraction of these have successfully been bound together in experiments to form antiatoms. Minuscule numbers of antiparticles can be generated at particle accelerators; however, total artificial production has been only a few nanograms. No macroscopic amount of antimatter has ever been assembled due to the extreme cost and difficulty of production and handling.

<span class="mw-page-title-main">Big Bang</span> How the universe expanded from a hot, dense state

The Big Bang event is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models of the Big Bang explain the evolution of the observable universe from the earliest known periods through its subsequent large-scale form. These models offer a comprehensive explanation for a broad range of observed phenomena, including the abundance of light elements, the cosmic microwave background (CMB) radiation, and large-scale structure. The overall uniformity of the Universe, known as the flatness problem, is explained through cosmic inflation: a sudden and very rapid expansion of space during the earliest moments. However, physics currently lacks a widely accepted theory of quantum gravity that can successfully model the earliest conditions of the Big Bang.

<span class="mw-page-title-main">Physical cosmology</span> Branch of cosmology which studies mathematical models of the universe

Physical cosmology is a branch of cosmology concerned with the study of cosmological models. A cosmological model, or simply cosmology, provides a description of the largest-scale structures and dynamics of the universe and allows study of fundamental questions about its origin, structure, evolution, and ultimate fate. Cosmology as a science originated with the Copernican principle, which implies that celestial bodies obey identical physical laws to those on Earth, and Newtonian mechanics, which first allowed those physical laws to be understood.

<span class="mw-page-title-main">Copernican principle</span> Principle that humans are not privileged observers of the universe

In physical cosmology, the Copernican principle states that humans, on the Earth or in the Solar System, are not privileged observers of the universe, that observations from the Earth are representative of observations from the average position in the universe. Named for Copernican heliocentrism, it is a working assumption that arises from a modified cosmological extension of Copernicus' argument of a moving Earth.

<span class="mw-page-title-main">Cosmic microwave background</span> Electromagnetic radiation as a remnant from an early stage of the universe in Big Bang cosmology

The cosmic microwave background is microwave radiation that fills all space in the observable universe. It is a remnant that provides an important source of data on the primordial universe. With a standard optical telescope, the background space between stars and galaxies is almost completely dark. However, a sufficiently sensitive radio telescope detects a faint background glow that is almost uniform and is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the radio spectrum. The accidental discovery of the CMB in 1965 by American radio astronomers Arno Penzias and Robert Wilson was the culmination of work initiated in the 1940s.

<span class="mw-page-title-main">Universe</span> Everything in space and time

The universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. The Big Bang theory is the prevailing cosmological description of the development of the universe. According to this theory, space and time emerged together 13.787±0.020 billion years ago, and the universe has been expanding ever since the Big Bang. While the spatial size of the entire universe is unknown, it is possible to measure the size of the observable universe, which is approximately 93 billion light-years in diameter at the present day.

<span class="mw-page-title-main">Hannes Alfvén</span> Swedish electrical engineer, plasma physicist and Nobel laureate

Hannes Olof Gösta Alfvén was a Swedish electrical engineer, plasma physicist and winner of the 1970 Nobel Prize in Physics for his work on magnetohydrodynamics (MHD). He described the class of MHD waves now known as Alfvén waves. He was originally trained as an electrical power engineer and later moved to research and teaching in the fields of plasma physics and electrical engineering. Alfvén made many contributions to plasma physics, including theories describing the behavior of aurorae, the Van Allen radiation belts, the effect of magnetic storms on the Earth's magnetic field, the terrestrial magnetosphere, and the dynamics of plasmas in the Milky Way galaxy.

In modern physical cosmology, the cosmological principle is the notion that the spatial distribution of matter in the universe is equally distributed and isotropic when viewed on a large enough scale, since the forces are expected to act equally throughout the universes on a large scale, and should, therefore, produce no observable inequalities in the large-scale structuring over the course of evolution of the matter field that was initially laid down by the Big Bang.

A non-standard cosmology is any physical cosmological model of the universe that was, or still is, proposed as an alternative to the then-current standard model of cosmology. The term non-standard is applied to any theory that does not conform to the scientific consensus. Because the term depends on the prevailing consensus, the meaning of the term changes over time. For example, hot dark matter would not have been considered non-standard in 1990, but would be in 2010. Conversely, a non-zero cosmological constant resulting in an accelerating universe would have been considered non-standard in 1990, but is part of the standard cosmology in 2010.

<span class="mw-page-title-main">Observable universe</span> All of space observable from the Earth at the present

The observable universe is a ball-shaped region of the universe comprising all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time; the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion. Initially, it was estimated that there may be 2 trillion galaxies in the observable universe, although that number was reduced in 2021 to only several hundred billion based on data from New Horizons. Assuming the universe is isotropic, the distance to the edge of the observable universe is roughly the same in every direction. That is, the observable universe is a spherical region centered on the observer. Every location in the universe has its own observable universe, which may or may not overlap with the one centered on Earth.

<span class="mw-page-title-main">Eric Lerner</span> American plasma researcher and popular science writer

Eric J. Lerner is an American popular science writer and independent plasma researcher. He wrote the 1991 book The Big Bang Never Happened, which advocates Hannes Alfvén's plasma cosmology instead of the Big Bang theory. He is founder, president, and chief scientist of Lawrenceville Plasma Physics, Inc.

The ΛCDM or Lambda-CDM model is a parameterization of the Big Bang cosmological model in which the universe contains three major components: first, a cosmological constant denoted by Lambda associated with dark energy; second, the postulated cold dark matter ; and third, ordinary matter. It is frequently referred to as the standard modelof Big Bang cosmology because it is the simplest model that provides a reasonably good account of the following properties of the cosmos:

In physical cosmology, structure formation is the formation of galaxies, galaxy clusters and larger structures from small early density fluctuations. The universe, as is now known from observations of the cosmic microwave background radiation, began in a hot, dense, nearly uniform state approximately 13.8 billion years ago. However, looking at the night sky today, structures on all scales can be seen, from stars and planets to galaxies. On even larger scales, galaxy clusters and sheet-like structures of galaxies are separated by enormous voids containing few galaxies. Structure formation attempts to model how these structures were formed by gravitational instability of small early ripples in spacetime density or another emergence.

<span class="mw-page-title-main">Birkeland current</span> Currents flowing along geomagnetic field lines

A Birkeland current is a set of electrical currents that flow along geomagnetic field lines connecting the Earth's magnetosphere to the Earth's high latitude ionosphere. In the Earth's magnetosphere, the currents are driven by the solar wind and interplanetary magnetic field and by bulk motions of plasma through the magnetosphere. The strength of the Birkeland currents changes with activity in the magnetosphere. Small scale variations in the upward current sheets accelerate magnetospheric electrons which, when they reach the upper atmosphere, create the Auroras Borealis and Australis. In the high latitude ionosphere, the Birkeland currents close through the region of the auroral electrojet, which flows perpendicular to the local magnetic field in the ionosphere. The Birkeland currents occur in two pairs of field-aligned current sheets. One pair extends from noon through the dusk sector to the midnight sector. The other pair extends from noon through the dawn sector to the midnight sector. The sheet on the high latitude side of the auroral zone is referred to as the Region 1 current sheet and the sheet on the low latitude side is referred to as the Region 2 current sheet.

A double layer is a structure in a plasma consisting of two parallel layers of opposite electrical charge. The sheets of charge, which are not necessarily planar, produce localised excursions of electric potential, resulting in a relatively strong electric field between the layers and weaker but more extensive compensating fields outside, which restore the global potential. Ions and electrons within the double layer are accelerated, decelerated, or deflected by the electric field, depending on their direction of motion.

The chronology of the universe describes the history and future of the universe according to Big Bang cosmology.

<span class="mw-page-title-main">Steady-state model</span> Model of the universe – alternative to the Big Bang model

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

<span class="mw-page-title-main">Anthony Peratt</span> American physicist

Anthony L. Peratt is an American physicist whose most notable achievements have been in plasma physics, nuclear fusion and the monitoring of nuclear weapons.