Aether (classical element)

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According to ancient and

medieval science, aether (/ˈθər/, alternative spellings include æther, aither, and ether), also known as the fifth element or quintessence, is the material that fills the region of the universe beyond the terrestrial sphere.[1] The concept of aether was used in several theories to explain several natural phenomena, such as the propagation of light and gravity. In the late 19th century, physicists postulated that aether permeated space, providing a medium through which light could travel in a vacuum, but evidence for the presence of such a medium was not found in the Michelson–Morley experiment, and this result has been interpreted to mean that no luminiferous aether exists.[2]

Mythological origins

The word αἰθήρ (aithḗr) in

Nyx in traditional Greek mythology.[5] Aether is related to αἴθω "to incinerate",[6] and intransitive "to burn, to shine" (related is the name Aithiopes (Ethiopians; see Aethiopia), meaning "people with a burnt (black) visage").[7][8]

Fifth element

Medieval concept of the cosmos. The innermost spheres are the terrestrial spheres, while the outer are made of aether and contain the celestial bodies.

In

philosophy. He noted that the four terrestrial classical elements were subject to change and naturally moved linearly. The first element however, located in the celestial regions and heavenly bodies, moved circularly and had none of the qualities the terrestrial classical elements had. It was neither hot nor cold, neither wet nor dry. With this addition the system of elements was extended to five and later commentators started referring to the new first one as the fifth and also called it aether, a word that Aristotle had used in On the Heavens and the Meteorology.[10]

Aether differed from the four terrestrial elements; it was incapable of motion of quality or motion of quantity. Aether was only capable of local motion. Aether naturally moved in circles, and had no contrary, or unnatural, motion. Aristotle also stated that celestial spheres made of aether held the stars and planets. The idea of aethereal spheres moving with natural circular motion led to Aristotle's explanation of the observed orbits of stars and planets in perfectly circular motion.[1][11]

Medieval scholastic philosophers granted aether changes of density, in which the bodies of the planets were considered to be more dense than the medium which filled the rest of the universe.[12] Robert Fludd stated that the aether was "subtler than light". Fludd cites the 3rd-century view of Plotinus, concerning the aether as penetrative and non-material.[13]

Quintessence

A stylized 𝓠 is sometimes used as a symbol for quintessence.[citation needed]
A symbol for quintessence in the works of Isaac Newton. Also abbreviated ⟨q̄⟩ and ⟨ē⟩.[14]
The symbol for aether in the works of Torbern Bergman (ca. 1775)

Quintessence (𝓠) is the

sulphur, "the stone which burns", which characterized the principle of combustibility, and mercury
, which contained the idealized principle of metallic properties.

This elemental system spread rapidly throughout all of Europe and became popular with alchemists, especially in medicinal alchemy. Medicinal alchemy then sought to isolate quintessence and incorporate it within medicine and elixirs.

elixirs, medicinal alchemy, and the philosopher's stone itself.[17]

Legacy

With the 18th century physics developments, physical models known as "aether theories" made use of a similar concept for the explanation of the propagation of electromagnetic and gravitational forces. As early as the 1670s, Newton used the idea of aether to help match observations to strict mechanical rules of his physics.[18][a] The early modern aether had little in common with the aether of classical elements from which the name was borrowed. These aether theories are considered to be scientifically obsolete, as the development of special relativity showed that Maxwell's equations do not require the aether for the transmission of these forces. Einstein noted that his own model which replaced these theories could itself be thought of as an aether, as it implied that the empty space between objects had its own physical properties.[20]

Despite the early modern aether models being superseded by general relativity, occasionally some physicists have attempted to reintroduce the concept of aether in an attempt to address perceived deficiencies in current physical models.[21] One proposed model of dark energy has been named "quintessence" by its proponents, in honor of the classical element.[22] This idea relates to the hypothetical form of dark energy postulated as an explanation of observations of an accelerating universe. It has also been called a fifth fundamental force.

Aether and light

The motion of light was a long-standing investigation in physics for hundreds of years before the 20th century. The use of aether to describe this motion was popular during the 17th and 18th centuries, including a theory proposed by Johann II Bernoulli, who was recognized in 1736 with the prize of the French Academy. In his theory, all space is permeated by aether containing "excessively small whirlpools". These whirlpools allow for aether to have a certain elasticity, transmitting vibrations from the corpuscular packets of light as they travel through.[23]

This theory of

de Broglie, which rejected the existence and necessity of aether to explain the various optical phenomena. These theories were supported by the results of the Michelson–Morley experiment in which evidence for the motion of aether was conclusively absent.[24] The results of the experiment influenced many physicists of the time and contributed to the eventual development of Einstein's theory of special relativity.[25]

Aether and gravitation

Jakob Bernoulli
, De gravitate aetheris, 1683

In 1682,

Jakob Bernoulli formulated the theory that the hardness of the bodies depended on the pressure of the aether.[26]
Aether has been used in various gravitational theories as a medium to help explain gravitation and what causes it.

Sir Isaac Newton

A few years later, aether was used in one of Sir Isaac Newton's first published theories of gravitation, Philosophiæ Naturalis Principia Mathematica (the Principia, 1687). He based the whole description of planetary motions on a theoretical law of dynamic interactions. He renounced standing attempts at accounting for this particular form of interaction between distant bodies by introducing a mechanism of propagation through an intervening medium.[27] He calls this intervening medium aether. In his aether model, Newton describes aether as a medium that "flows" continually downward toward the Earth's surface and is partially absorbed and partially diffused. This "circulation" of aether is what he associated the force of gravity with to help explain the action of gravity in a non-mechanical fashion.[27] This theory described different aether densities, creating an aether density gradient. His theory also explains that aether was dense within objects and rare without them. As particles of denser aether interacted with the rare aether they were attracted back to the dense aether much like cooling vapors of water are attracted back to each other to form water.[28] In the Principia he attempts to explain the elasticity and movement of aether by relating aether to his static model of fluids. This elastic interaction is what caused the pull of gravity to take place, according to this early theory, and allowed an explanation for action at a distance instead of action through direct contact. Newton also explained this changing rarity and density of aether in his letter to Robert Boyle in 1679.[28] He illustrated aether and its field around objects in this letter as well and used this as a way to inform Robert Boyle about his theory.[29] Although Newton eventually changed his theory of gravitation to one involving force and the laws of motion, his starting point for the modern understanding and explanation of gravity came from his original aether model on gravitation.[30][self-published source?]

See also

References

Footnotes

  1. ^ In a 1675 paper, he also wrote a number of pages speculating that aether may explain how the soul interacts with the body.[19]

Citations

  1. ^ , Believing that the movements of the heavenly bodies are continuous, natural and circular, and that the natural movements of the four terrestrial elements are rectilinear and discontinuous, Aristotle concluded that the heavenly bodies must be composed of a fifth element, aither [sic].
  2. ^ Carl S. Helrich, The Classical Theory of Fields: Electromagnetism Berlin, Springer 2012, p. 26.
  3. .
  4. .
  5. ^ "AITHER". AETHER : Greek protogenos god of upper air & light; mythology : AITHER. Retrieved January 16, 2016.
  6. ^ Pokorny, Julius (1959). Indogermanisches etymologisches Wörterbuch, s.v. ai-dh-.
  7. ^ Αἰθίοψ in Liddell, Scott, A Greek–English Lexicon: "Αἰθίοψ, οπος, ὁ, fem. Αἰθιοπίς, ίδος, ἡ (Αἰθίοψ as fem., A.Fr.328, 329): pl. 'Αἰθιοπῆες' Il.1.423, whence nom. 'Αἰθιοπεύς' Call.Del.208: (αἴθω, ὄψ):— properly, Burnt-face, i.e. Ethiopian, negro, Hom., etc.; prov., Αἰθίοπα σμήχειν 'to wash a blackamoor white', Luc.Ind. 28." Cf. Etymologicum Genuinum s.v. Αἰθίοψ, Etymologicum Gudianum s.v.v. Αἰθίοψ. "Αἰθίοψ". Etymologicum Magnum (in Greek). Leipzig: Lipsiae Apud J.A.G. Weigel. 1818.
  8. . Retrieved 20 January 2015. ...[Africa's Indian Ocean] coast was called Azania, and no 'Ethiopeans', dark skinned people, were mentioned amongst its inhabitants.
  9. ^ Plato, Timaeus 58d.
  10. S2CID 170926485
    .
  11. ^ George Smoot III. "Aristotle's Physics". lbl.gov. Archived from the original on 20 December 2016. Retrieved 20 December 2016.
  12. .
  13. ^ Robert Fludd, "Mosaical Philosophy". London, Humphrey Moseley, 1659, p. 221.
  14. ^ B.J.T. Dobbs (1983) The Foundations of Newton's Alchemy, p. xiv.
  15. ^ a b The Alchemists, F. Sherwood Taylor, page 95.
  16. ^ The book of Quintessence Archived 2015-09-24 at the Wayback Machine, Early English Text Society original series number 16, edited by F. J. Furnivall.
  17. ^ The Dictionary of Alchemy, Mark Haeffner.
  18. ^ Margaret Osler, Reconfiguring the World. The Johns Hopkins University Press 2010. (155).
  19. .
  20. ^ Einstein, Albert: "Ether and the Theory of Relativity" (1920), republished in Sidelights on Relativity (Methuen, London, 1922)
  21. S2CID 4288946
    .
  22. .
  23. ^ Whittaker, Edmund Taylor, A History of the Theories of Aether and Electricity from the Age of Descartes to the Close of the 19th Century (1910), pp. 101-02.
  24. S2CID 130423116
    .
  25. .
  26. ^ "Bernoulli nell'Enciclopedia Treccani".
  27. ^
    S2CID 122494617
    .
  28. ^ a b Newton, Isaac."Isaac Newton to Robert Boyle, 1679." 28 February 1679.
  29. ^ James DeMeo (2009). "Isaac Newton's Letter to Robert Boyle, on the Cosmic Ether of Space - 1679". orgonelab.org. Archived from the original on 20 December 2016. Retrieved 20 December 2016.
  30. ISBN 9781329053083. Retrieved 20 December 2016.[self-published source
    ]