At the beginning of 19. century the English polymath T.Yong demonstrated that light behaves like a wave. The luminiferous aether (or ether) is defined to be whatever medium transmits the light waves.
The Michelson-Morley experiment in 1887 failed to detect any motion of the Earth relative to the aether. Henri Poincaré conjectured that the aether may be unobservable, and invented special relativity based on the notion that the aether may be superfluous. Albert Einstein published conflicting opinions on whether the aether exists. According to R.Humphreys Einstein’s theories of special and general relativity not only stem from Maxwell’s work which required existence of ether as one of its postulates, but at bottom they only make sense if space (and time) is some kind of “stuff”. Humphreys portrays Einstein as recanting in 1920 his 1905 denial of the 19th century idea of an “ether” meant to propagate light waves.
Quantum electrodynamics (QED) teaches that when light goes through a vacuum, it is really going through a sea of virtual particles. Cosmologists say that the vacuum is really filled with dark energy, and it is unknown whether that has any relation to the aether concept. According to these theories, there is no such thing as empty space. The aether describes space when it is as empty as possible.
Reasons for long support of aether hypothesis
A.N. Whitehead states 5 reasons that had provided for long the support for acceptance of aether hypothesis:
- The wave theory of light required existence of ether as one of its postulates
- Maxwell's Equations describe electrostatic and magnetic attractions by means of describing the status changes of ether
- Maxwell's Equations assume events in a space that is evidently void. There must be something to which these properties could be ascribed.
- The identification of light with electromagnetic waves performed by C.Maxwell shows that the same entity (aether) is implied by at first glance different optical and electromagnetic phenomena thus should be able to unify their interpretation
- The possibility to perceive static "ether sea" which homogeneously penetrates all space of cosmos as absolute frame of reference towards which the Newton's laws of motion are referenced. Ether acquires this special character in Lorentz's and Larmore's theory however such extrapolation is discouraged by Whitehead as it is rooted in solely speculative entity lacking any experimental evidence.
Politically incorrect term
YEC creationist R.Humphreys states that in contemporary mainstream science the term ether have become politically incorrect and although there are many various paradoxes in physics that could be addressed by de facto aether hypothesis, the materialistic scientists are verbally "beating-around-the-bush" and use many code words such as various combinations of: “spacetime,” “continuum,” “manifold,” “quantum vacuum,” “the Vacuum,” “substratum,” “Dirac sea,” “plenum,” and “medium,”—all just to avoid using the word “ether”.
- David Berlinski. "The Reason", The Devil’s Delusion. Basic Books, New York, 2009, 90–93. ISBN 978-0-465-01937-3. “In the early years of the nineteenth century, the English polymath Thomas Young demonstrated that light behaves like a wave. ...Light, they argued, is both like a wave and like a particle, and what is more, it is like wave and like a particle on the level of individual photons themselves.”
- Russell Humphreys. God’s mighty expanse. Creation Ministries International. Retrieved on 2012-10-08. “Einstein’s theories of special and general relativity not only stem from Maxwell’s work, but at bottom they only make sense if space (and time) is some kind of “stuff,” as Einstein finally acknowledged in a little-known speech in 1920.2 The famous limit for the speeds of light and particles, c, could only work if there were a real material to enforce the speed limit. (Why should there be a limit if space were completely empty?) Space could be “warped” or “bent” only if it were actual solid matter. ...Strangely, academic materialists have tried to ignore the physics clues that space is a material, probably for religious and philosophical reasons. They even ignored Einstein’s 1920 recantation (see second item above) of his 1905 denial of the 19th-century idea of an “ether” (or “aether”) meant to propagate light waves. The academics have made the word “ether” politically incorrect. Now that it looks as if the ether idea merely needed a bit more sophistication, physicists use many code words for it, such as various combinations of: “spacetime,” “continuum,” “manifold,” “quantum vacuum,” “the Vacuum,” “substratum,” “Dirac sea,” “plenum,” and “medium,”—all to avoid using the word “ether.” This verbal beating-around-the-bush amuses me. It prevents academics from explaining relativity and quantum mechanics in simple, visualizable terms that solve the various paradoxes. I suspect the academic experts on relativity and quantum theories prefer to keep them arcane and perplexing (to other academics as well), because the mystery makes them the high priests of a secular religion for which the public needs interpreters.”
- Moshe Carmeli (2002). Cosmological Special Relativity, The Large-Scale Structure of Space, Time and Velocity, 2nd Edition. World Scientific Publishing, 22. ISBN 9-789-02-4936-5. “...Does this mean that the hypothetical dark matter can be abolished just as the "luminiferous ether" was proved to be superfluous by special relativity?”
- A. N. Whitehead (1919, 1925, 2011). "5.The Ether", An Enquiry Concerning the Principles of Natural Knowledge. Cambridge University Press. ISBN 978-1-107-60012-6.