James, William, The Will to Believe, 1895; and earlier in 1895, as cited in OED's new 2003 entry for "multiverse": "1895 W. JAMES in Internat. Jrnl. Ethics 6 10 Visible nature is all plasticity and indifference, a multiverse, as one might call it, and not a universe."
Tegmark, Max (May 2003). "Parallel Universes". Scientific American.
Tegmark, Max (January 23 2003). Parallel Universes. Retrieved on 2006-02-07. (PDF).
Ellis, George F.R.; U. Kirchner, W.R. Stoeger (2004). "Multiverses and physical cosmology". Monthly Notices of the Royal Astronomical Society 347: 921-936. Retrieved on 2007-01-09.
Breitbart.com, Parallel universes exist - study, Sept 23 2007
Merali, Zeeya (2007-09-21), "Parallel universes make quantum sense", New Scientist (no. 2622), <http://space.newscientist.com/article/mg19526223.700-parallel-universes-make-quantum-sense.html>. Retrieved on 20 October 2007 (Summary only).
Tegmark, Max, The Interpretation of Quantum Mechanics: Many Worlds or Many Words?, 1998. To quote: "What Everett does NOT postulate: "At certain magic instances, the world undergoes some sort of metaphysical 'split' into two branches that subsequently never interact." This is not only a misrepresentation of the MWI, but also inconsistent with the Everett postulate, since the subsequent time evolution could in principle make the two terms...interfere. According to the MWI, there is, was and always will be only one wavefunction, and only decoherence calculations, not postulates, can tell us when it is a good approximation to treat two terms as non-interacting."
Deutsch, David, David Deutsch's Many Worlds, Frontiers, 1998.
Lewis, David (1986). On the Plurality of Worlds. Basil Blackwell.
Paul B. Kantor "The Interpretation of Cultures and Possible Worlds", 1 October 2002
Carl Sagan, Placido P D'Souza (1980s). Hindu cosmology's time-scale for the universe is in consonance with modern science.; Dick Teresi (2002). Lost Discoveries : The Ancient Roots of Modern Science – from the Babylonians to the Maya.
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A multiverse (or meta-universe) is the hypothetical set of multiple possible universes (including our universe) that together comprise all of reality. The different universes within a multiverse are sometimes called parallel universes.
The structure of the multiverse, the nature of each
universe within it and the relationship between the various
constituent universes, depend on the specific multiverse hypothesis
considered.
In these contexts, parallel universes are also called,
The possibility of many universes raises various scientific and philosophical questions.
According to Max Tegmark,[2] the existence of other universes is a direct implication of cosmological observations.
Tegmark describes the set of related concepts which share the notion
that there are universes beyond the familiar observable one, and
goes on to provide a taxonomy of parallel universes organized by
levels.[3]
Classification
In order to clarify terminology, George Ellis, U. Kirchner and W.R. Stoeger recommend using the term,
The levels according to Tegmark's classification and using Ellis, Koechner and Stoeger's terminology are briefly described below.
"Bubble universes", every disk is a bubble universe (Universe 1 to Universe 6 are different bubbles, they have physical constants that are different from our universe), our universe is just one of the bubbles.
Bubble theory posits an infinite number of open multiverses, each with different physical constants. (The set of bubble universes is thus a Level II multiverse.)
Counter-intuitively, these universes
are farther away than even the farthest universe in our open multiverse.
On very small scales, the foam is frothing due to energy fluctuations. These fluctuations may create tiny bubbles and wormholes. If the energy fluctuation is not very large, a tiny bubble universe may form, experience some expansion like an inflating balloon, and then contract and disappear from existence.
However, if the energy fluctuation is greater than a particular
critical value, a tiny bubble universe forms from the parent
universe, experiences long-term expansion, and allows matter and
large-scale galactic structures to form.
Many worlds interpretation of quantum physics
Hugh Everett's many-worlds interpretation (MWI) is one of several mainstream interpretations of quantum mechanics.
Other interpretations include the Copenhagen and the consistent histories interpretations. The multiverse proposed by MWI has a shared time parameter. In most formulations, all the constituent universes are structurally identical to each other and though they have the same physical laws and values for the fundamental constants, they may exist in different states.
The constituent universes are furthermore non-communicating, in the sense that no information can pass between them, although in Everett's formulation they may potentially affect each other [7] through quantum interference.[8]
The state of the entire multiverse is related to the states of the constituent universes by quantum superposition, and is described by a single universal wave-function.
Related are Richard Feynman's multiple
histories interpretation and H. Dieter Zeh's many-minds
interpretation.
If the Many worlds interpretation is true there are so many copies of our universe that the existence of at least one planet like Earth is not surprising.
M-theory
A multiverse of a somewhat different kind has been envisaged within the 11-dimensional extension of string theory known as M-theory. In M-theory our universe and others are created by collisions between membranes in an 11-dimensional space.
Unlike the universes in the
"quantum multiverse", these universes can have different laws of
physics.
The string landscape theory asserts that a different universe exists
for each of the very large ensemble of solutions generated when ten
dimensional string theory is reduced to the four-dimensional
low-energy world we see.
Criticisms of multiverse theories
Thus, according to Tegmark, paradoxically the
multiverse scenario is more parsimonious than that of a single
universe.
This possibility is also expressed in theories such as determinism and chaos theory.
The hope is sometimes
expressed that once a grand unified theory of everything is
achieved, it will turn out to have a unique "solution" corresponding
to the observed universe.
William Dembski in particular,
derides it as inflating explanatory resources without evidence or
warrant, and terms such concepts "inflatons".[10]
The concept of other universes has been proposed to explain why our universe seems to be fine-tuned for conscious life as we experience it.
If there were a large number (possibly infinite) of different physical laws (or fundamental constants) in as many universes, some of these would have laws that were suitable for stars, planets and life to exist.
The
anthropic principle could then be applied to
conclude that we would only consciously exist in those universes
which were finely-tuned for our conscious existence. Thus, while the
probability might be extremely small that there is life in most of
the multiverses, this scarcity of life-supporting universes does not
imply intelligent design as the only explanation of our existence.
Dr. Gould compared it to claiming that sausages were originally made long and narrow so that they would fit modern hotdog buns, or that humans evolved fingernails so that fingernail polish would be invented.
Critics cite the vast store of
evolutionary evidence which shows that life is perfectly and
naturally tuned to the universe it arose in. Fossil, genetic and
other biological evidence abundantly supports the observation that
life adapts to physics, not the other way around.
Additionally, possible worlds are a way of explaining probability,
hypothetical statements and the like, and some philosophers such as
David Lewis believe that all possible worlds exist, and are just as
real as the actual world (a position known as modal realism).[11]
A metaphysical issue that crops up in multiverse schema that posit infinite identical copies of any given universe is that of the notion that there can be identical objects in different possible worlds.
According to the counterpart theory of David Lewis, the
objects should be regarded as similar rather than identical.[12][13]
Virtual realities as a multiverse
For such
beings, their "fake" universe will appear indistinguishable from
reality.
The earliest known records describing the concept of a multiverse are found in ancient Hindu cosmology, in texts such as the Puranas.
They expressed the idea of an infinite number of universes, each with its own gods, inhabitants and planets, and an infinite cycle of births, deaths, and rebirths of a universe, with each cycle lasting 8.4 billion years.
The belief is too that the number of universes is
infinite.[14]
'Fictional' multiverses
For some it serves primarily as a plot device, a means to put characters into an unfamiliar situation, or a framework that usually lies in the background for continuity purposes.
For others it is a major theme and focus of the work. It is sometimes used as the basis for exploring "what if" scenarios, such as in alternate history stories. The TV show Sliders from the 1990's first popularized the concept through the TV entertainment medium.
The film The One (2002) starring Jet Li carried the same idea to the action film medium. The popular MYST computer game franchise uses concepts of describing a world and then linking to that world, which is part of a multiverse of infinite possible and concurrently existing universes, matching the descriptions.
Also, the computer game Legacy of Kain: Soul Reaver and its sequels feature two distinct parallel universes.
The protagonist, Raziel, is capable of existing in both the Material Realm, or normal reality, and the Spectral Realm, a dark and distorted version of the former with its own physics and properties.
The Michael Crichton novel
Timeline featured a method for what appeared to be time travel by
traveling to parallel universes that are identical except for the
moment of their birth, thus rendering off-set yet parallel time.
In the 1980s DC published the ever popular Crisis on Infinite Earths which detailed a breakdown of the Multiverse at the hands of the Anti-Monitor.
The television series Star Trek has many times gone into parallel "Mirror" universes, and Stargate SG-1 has postulated parallel universes. The Anime series Bokurano is based on a multiverse. In the BBC television show Doctor Who, the Doctor travels between parallel universes and is parted indefinitely from his companion Rose Tyler when she becomes trapped within one.
The
fantasy trilogy His Dark Materials by Philip Pullman is set in
multiple parallel universes.
La idea de que el universo
que se puede observar es solo una parte de la realidad física dio
luz a la definición del concepto "multiverso".
El término "multiverso" se inventó en diciembre de 1960, por Andy Nimmo, aquel entonces vice-director de la British Interplanetary Society de Escocia cuando dio un discurso para dicha organización acerca de la interpretación "varios-mundos" de la física cuántica que se había publicado en 1957.
La definición original de "multiverso" era:
A partir de este discurso, la palabra se usó correcta e incorrectamente por unos años en varias instancias en grupos científicos y de ciencia ficción.
En los años 60, el autor de
ciencia ficción, Michael Moorcock, interpretó la palabra en una
novela. Gracias a nuevas interpretaciones populares basadas en esta
obra, la palabra se usa en varios contextos y, se podría decir, con
un "multiverso" de definiciones.
Aunque el multiverso principalmente muy usado en la ciencia ficción, actualmente la propuesta de la posible existencia de un multiverso igualmente se ha originado como una consecuencia de teorías físicas elaboradas, como la teoría de las cuerdas; en la que se desea llegar a obtener una teoría del todo que explique el universo.
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