Aether theories

Aether theories in physics propose the existence of a medium, the aether (also spelled ether, from the Greek word (αἰθήρ), meaning "upper air" or "pure, fresh air"), a space-filling substance or field, thought to be necessary as a transmission medium for the propagation of electromagnetic or gravitational forces. The assorted aether theories embody the various conceptions of this "medium" and "substance". This early modern aether has little in common with the aether of classical elements from which the name was borrowed. Since the development of special relativity, theories using a substantial aether are not used any more in modern physics, and are replaced by more abstract models.

Historical models

Luminiferous aether

Main articles: Luminiferous aether and History of special relativity

In the 19th century, luminiferous aether (or ether), meaning light-bearing aether, was a theorized medium for the propagation of light (electromagnetic radiation). However, a series of increasingly complex experiments had been carried out in the late 1800s like the Michelson-Morley experiment in an attempt to detect the motion of earth through the aether, and had failed to do so. A range of proposed aether-dragging theories could explain the null result but these were more complex, and tended to use arbitrary-looking coefficients and physical assumptions. Joseph Larmor discussed the aether in terms of a moving magnetic field caused by the acceleration of electrons. Hendrik Lorentz and George Francis FitzGerald offered within the framework of Lorentz ether theory a more elegant solution to how the motion of an absolute aether could be undetectable (length contraction), but if their equations were correct, Albert Einstein's 1905 special theory of relativity could generate the same mathematics without referring to an aether at all. This led most physicists to conclude that this early modern notion of a luminiferous aether was not a useful concept.

Mechanical gravitational aether

Main article: Mechanical explanations of gravitation

From the 16th until the late 19th century, gravitational phenomena had also been modeled utilizing an aether. The most well-known formulation is Le Sage's theory of gravitation, although other models were proposed by Isaac Newton, Bernhard Riemann, and Lord Kelvin. None of those concepts is considered to be viable by the scientific community today.

Non-standard interpretations in modern physics

General relativity

Main article: Einstein's views on the aether

Einstein sometimes used the word aether for the gravitational field within general relativity, but this terminology never gained widespread support.

We may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an aether. According to the general theory of relativity space without aether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense. But this aether may not be thought of as endowed with the quality characteristic of ponderable media, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it.

Quantum vacuum

Quantum mechanics can be used to describe spacetime as being non-empty at extremely small scales, fluctuating and generating particle pairs that appear and disappear incredibly quickly. It has been suggested by some such as Paul Dirac that this quantum vacuum may be the equivalent in modern physics of a particulate aether. However, Dirac's aether hypothesis was motivated by his dissatisfaction with quantum electrodynamics, and it never gained support by the mainstream scientific community.

Robert B. Laughlin, Nobel Laureate in Physics, endowed chair in physics, Stanford University, had this to say about ether in contemporary theoretical physics:

It is ironic that Einstein's most creative work, the general theory of relativity, should boil down to conceptualizing space as a medium when his original premise [in special relativity] was that no such medium existed [..] The word 'ether' has extremely negative connotations in theoretical physics because of its past association with opposition to relativity. This is unfortunate because, stripped of these connotations, it rather nicely captures the way most physicists actually think about the vacuum. . . . Relativity actually says nothing about the existence or nonexistence of matter pervading the universe, only that any such matter must have relativistic symmetry. [..] It turns out that such matter exists. About the time relativity was becoming accepted, studies of radioactivity began showing that the empty vacuum of space had spectroscopic structure similar to that of ordinary quantum solids and fluids. Subsequent studies with large particle accelerators have now led us to understand that space is more like a piece of window glass than ideal Newtonian emptiness. It is filled with 'stuff' that is normally transparent but can be made visible by hitting it sufficiently hard to knock out a part. The modern concept of the vacuum of space, confirmed every day by experiment, is a relativistic ether. But we do not call it this because it is taboo.

Pilot waves

Main articles: Pilot wave and De Broglie–Bohm theory

Louis de Broglie stated, "Any particle, even isolated, has to be imagined as in continuous “energetic contact” with a hidden medium."

Dark Energy as Aether

There has been a lot of discussion about dark energy and dark matter as concepts to explain certain anomalies in physics such as between mass and gravity. Some scientists are starting to see dark energy as a new reference to the concept of the aether.

Earlier, New Scientist reported on research by a team at the University of Oxford seeking to link dark energy and the aether to resolve a problem with gravity and mass.

Starkman and colleagues Tom Zlosnik and Pedro Ferreira of the University of Oxford are now reincarnating the ether in a new form to solve the puzzle of dark matter, the mysterious substance that was proposed to explain why galaxies seem to contain much more mass than can be accounted for by visible matter. They posit an ether that is a field, rather than a substance, and which pervades space-time.

This is not the first time that physicists have suggested modifying gravity to do away with this unseen dark matter. The idea was originally proposed by Mordehai Milgrom while at Princeton University in the 1980s. He suggested that the inverse-square law of gravity only applies where the acceleration caused by the field is above a certain threshold, say a0. Below that value, the field dissipates more slowly, explaining the observed extra gravity. "It wasn't really a theory, it was a guess," says cosmologist Sean Carroll at the University of Chicago in Illinois.

Then in 2004 this idea of modified Newtonian dynamics (MOND) was reconciled with general relativity by Jacob Bekenstein at the Hebrew University in Jerusalem, Israel (New Scientist, 22 January 2005, p 10), making MOND a genuine contender in the eyes of some physicists...

Now Starkman's team has reproduced Bekenstein's results using just one field - the new ether (www.arxiv.org/astro-ph/ 0607411). Even more tantalisingly, the calculations reveal a close relationship between the threshold acceleration a0 - which depends on the ether - and the rate at which the universe's expansion is accelerating. Astronomers have attributed this acceleration to something called dark energy, so in a sense the ether is related to this entity. That they have found this connection is a truly profound thing, says Bekenstein. The team is now investigating how the ether might cause the universe's expansion to speed up.

Andreas Albrecht, a cosmologist at the University of California, Davis, believes that this ether model is worth investigating further. "We've hit some really profound problems with cosmology Ð with dark matter and dark energy," he says. "That tells us we have to rethink fundamental physics and try something new."

Superluminal Aether

The peer-reviewed publication of May 2012 titled “The Theory of the Hidden Variable Behind (HVB or hidbi): The Quantization of Duality” is a technical paper about philosophy of physics expanding the theory of hidden variables in quantum mechanics proposed by Einstein, Podolsky, and Rosen in the EPR paradox. The theory proposes an explanation to the origins of matter from re-interpretations of the electromagnetic equations of Maxwell. The framework of the theory is fundamentally based on the concepts of the orientation of the magnetic field (B) with respect to the electric field (E), energy localization/delocalization through lower/higher number of energy levels, global minimization of energy use, and the transference of atomic/subatomic quantum rules into the macro world to explain existence. The comparison of the micro world with macro world is justified by the presence of repeated patterns or algorithms throughout all science fields. The hidbi theory considers that all fundamental particles, and hence the whole universe, is a vibration transmitted through a medium or ether or parental matrix. In this model the universe is relative to the speed of light (luminal) and the matrix or ether is relative to speeds faster than the speed of light or tachyon-like (superluminal).

In the hidbi theory the model of the atomic harmonic oscillator is transferred to represent the universe as the analogous to an atomic p orbital, resembling an eddy or storm moving slower on the rushing waters of a river or matrix/ether. In analogy with the domino effect in which what is transmitted from point A to point B is the energy associated with the motion and not the solid dominoes, the traveling energy represents the living universe and the dominoes represent the “static” points of the matrix where the universe is being manifested at a time t. The hidbi theory proposes that what propagates in the matrix/ether is an energy carrying a code of instructions that are “eternally” or periodically or constantly repeated to rebuild/replace the universe with the matter of the matrix available on any particular point A or B. In order to account for the second law of thermodynamics, one principal rule around the re-application of the instructions is that the universe must be replaced with increased entropy or disorder. The theory also proposes that there could be a mechanism analogous to the DNA transcription and translation responsible for transferring the instructions of the universe through the matrix/ether and translating it into solid objects at any particular point of the matrix/ether. In addition, time is treated as a waveparticle resulting as a consequence of the initial slowed-down of matrix matter and thus it represents the stage in which heavier particles such as protons and electrons can manifest. In summary, the hidbi theory suggests the idea that the universe evolves in an envelope of time made from lent or bent matter of the superluminal matrix/ether, slowed-down or distorted to luminal speeds, and replaced with newly disordered matter of the matrix/ether every time it moves from point A to point B. The superluminal motion of the matrix can appear immobile when observed from the human point of view, thus allowing physics to operate under the impression that it is not existent. This may be used as a fair argument to clarify ether “conflicts” such as the one apparently posed by special relativity, a theory based on framework that works without the presence of an ether.

See also

• Absolute space and time
• Apeiron (cosmology)

Further reading

• Whittaker, Edmund Taylor (1910), A History of the theories of aether and electricity (1 ed.), Dublin: Longman, Green and Co.
• Schaffner, Kenneth F. (1972), Nineteenth-century aether theories, Oxford: Pergamon Press, ISBN 0-08-015674-6
• Darrigol, Olivier (2000), Electrodynamics from Ampére to Einstein, Oxford: Clarendon Press, ISBN 0-19-850594-9
• Maxwell, James Clerk (1878), "Ether", Encyclopædia Britannica Ninth Edition, 8: 568–572
• Harman, P.H. (1982), Energy, Force and Matter: The Conceptual Development of Nineteenth Century Physics, Cambridge: Cambridge University Press, ISBN 0-521-28812-6
• Decaen, Christopher A. (2004), "Aristotle's Aether and Contemporary Science", The Thomist, 68: 375–429, retrieved 2011-03-05.
• Joseph Larmor, "Ether", Encyclopædia Britannica, Eleventh Edition (1911).
• Oliver Lodge, "Ether", Encyclopædia Britannica, Thirteenth Edition (1926).
• "A Ridiculously Brief History of Electricity and Magnetism; Mostly from E. T. Whittaker’s A History of the Theories of Aether and Electricity". (PDF format)
• Epple, M. Topology, Matter, and Space, I: Topological Notions in 19th-Century Natural Philosophy. Arch. Hist. Exact Sci. 52 (1998) 297–392.