According to ancient and
medieval science
The history of science covers the development of science from ancient times to the present. It encompasses all three major branches of science: natural, social, and formal.
Science's earliest roots can be traced to Ancient Egypt and Mesopo ...
, aether (, 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
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. Acc ...
beyond the
terrestrial sphere.
The concept of aether was used in several theories to explain several natural phenomena, such as the traveling of light and gravity. In the late 19th century, physicists postulated that aether permeated all throughout space, providing a medium through which light could travel in a
vacuum
A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often dis ...
, but evidence for the presence of such a medium was not found in the
Michelson–Morley experiment
The Michelson–Morley experiment was an attempt to detect the existence of the luminiferous aether, a supposed medium permeating space that was thought to be the carrier of light waves. The experiment was performed between April and July 1887 ...
, and this result has been interpreted as meaning that no such
luminiferous aether
Luminiferous aether or ether ("luminiferous", meaning "light-bearing") was the postulated medium for the propagation of light. It was invoked to explain the ability of the apparently wave-based light to propagate through empty space (a vacuum), so ...
exists.
Mythological origins
The word (''aithḗr'') in
Homeric Greek
Homeric Greek is the form of the Greek language that was used by Homer in the ''Iliad'', ''Odyssey'', and Homeric Hymns. It is a literary dialect of Ancient Greek consisting mainly of Ionic, with some Aeolic forms, a few from Arcadocypriot, and ...
means "pure, fresh air" or "clear sky". In
Greek mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...
, it was thought to be the pure essence that the gods breathed, filling the space where they lived, analogous to the ''
air
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for ...
'' breathed by mortals. It is also personified as a deity,
Aether, the son of
Erebus
In Greek mythology, Erebus (; grc, Ἔρεβος, Érebos, "deep darkness, shadow".), or Erebos, is the personification of darkness and one of the primordial deities. Hesiod's ''Theogony'' identifies him as one of the first five beings in exis ...
and
Nyx in traditional Greek mythology. Aether is related to "to incinerate", and intransitive "to burn, to shine" (related is the name ''Aithiopes'' (
Ethiopia
Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the ...
ns; see
Aethiopia
Ancient Aethiopia, ( gr, Αἰθιοπία, Aithiopía; also known as Ethiopia) first appears as a geographical term in classical documents in reference to the upper Nile region of Sudan, as well as certain areas south of the Sahara desert. It ...
), meaning "people with a burnt (black) visage").
Fifth element
![Ptolemaicsystem-small](https://upload.wikimedia.org/wikipedia/commons/3/3a/Ptolemaicsystem-small.png)
In
Plato
Plato ( ; grc-gre, Πλάτων ; 428/427 or 424/423 – 348/347 BC) was a Greek philosopher born in Athens during the Classical period in Ancient Greece. He founded the Platonist school of thought and the Academy, the first institution ...
's ''
Timaeus Timaeus (or Timaios) is a Greek name. It may refer to:
* ''Timaeus'' (dialogue), a Socratic dialogue by Plato
*Timaeus of Locri, 5th-century BC Pythagorean philosopher, appearing in Plato's dialogue
*Timaeus (historian) (c. 345 BC-c. 250 BC), Greek ...
'' (58d) speaking about air, Plato mentions that "there is the most translucent kind which is called by the name of aether (αἰθήρ)" but otherwise he adopted the classical system of four elements.
Aristotle
Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...
, who had been Plato's student at the
Academy
An academy ( Attic Greek: Ἀκαδήμεια; Koine Greek Ἀκαδημία) is an institution of secondary or tertiary higher learning (and generally also research or honorary membership). The name traces back to Plato's school of philosophy ...
, agreed on this point with his former mentor, emphasizing additionally that fire has sometimes been mistaken for aether. However, in his Book ''
On the Heavens
''On the Heavens'' (Greek: ''Περὶ οὐρανοῦ''; Latin: ''De Caelo'' or ''De Caelo et Mundo'') is Aristotle's chief cosmological treatise: written in 350 BC, it contains his astronomical theory and his ideas on the concrete workings o ...
'' he introduced a new "first" element to the system of the
classical element
Classical elements typically refer to earth, water, air, fire, and (later) aether which were proposed to explain the nature and complexity of all matter in terms of simpler substances. Ancient cultures in Greece, Tibet, and India had simil ...
s of
Ionian philosophy
Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often posed as problems to be studied or resolved. Some ...
. 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 not used.
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 noted that
celestial spheres
The celestial spheres, or celestial orbs, were the fundamental entities of the cosmology, cosmological models developed by Plato, Eudoxus of Cnidus, Eudoxus, Aristotle, Ptolemy, Copernicus, and others. In these celestial models, the diurnal m ...
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.
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.
Robert Fludd
Robert Fludd, also known as Robertus de Fluctibus (17 January 1574 – 8 September 1637), was a prominent English Paracelsian physician with both scientific and occult interests. He is remembered as an astrologer, mathematician, cosmologis ...
stated that the aether was "subtler than light". Fludd cites the 3rd-century view of
Plotinus
Plotinus (; grc-gre, Πλωτῖνος, ''Plōtînos''; – 270 CE) was a philosopher in the Hellenistic philosophy, Hellenistic tradition, born and raised in Roman Egypt. Plotinus is regarded by modern scholarship as the founder of Neop ...
, concerning the aether as penetrative and non-material.
Quintessence
upright=0.5, A stylized 𝓠 is sometimes used as a symbol for quintessence.
![Bismuth trident symbol](https://upload.wikimedia.org/wikipedia/commons/4/46/Bismuth_trident_symbol.svg)
Quintessence (𝓠) is the
Latinate
Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...
name of the fifth element used by medieval alchemists for a medium similar or identical to that thought to make up the heavenly bodies. It was noted that there was very little presence of quintessence within the terrestrial sphere. Due to the low presence of quintessence, earth could be affected by what takes place within the heavenly bodies.
[''The Alchemists'', F. Sherwood Taylor, page 95.] This theory was developed in the 14th century text ''The testament of Lullius'', attributed to
Ramon Llull
Ramon Llull (; c. 1232 – c. 1315/16) was a philosopher, theologian, poet, missionary, and Christian apologist from the Kingdom of Majorca.
He invented a philosophical system known as the ''Art'', conceived as a type of universal logic to pro ...
. The use of quintessence became popular within medieval alchemy. Quintessence stemmed from the medieval elemental system, which consisted of the four classical elements, and aether, or quintessence, in addition to two chemical elements representing metals:
sulphur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...
, "the stone which burns", which characterized the principle of combustibility, and
mercury
Mercury commonly refers to:
* Mercury (planet), the nearest planet to the Sun
* Mercury (element), a metallic chemical element with the symbol Hg
* Mercury (mythology), a Roman god
Mercury or The Mercury may also refer to:
Companies
* Merc ...
, 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.
Due to quintessence's pure and heavenly quality, it was thought that through consumption one may rid oneself of any impurities or illnesses. In ''The book of Quintessence'', a 15th-century English translation of a continental text, quintessence was used as a medicine for many of man's illnesses. A process given for the creation of quintessence is
distillation
Distillation, or classical distillation, is the process of separation process, separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distilla ...
of alcohol seven times. Over the years, the term quintessence has become synonymous with
elixirs
ELIXIR (the European life-sciences Infrastructure for biological Information) is an initiative that will allow life science laboratories across Europe to share and store their research data as part of an organised network. Its goal is to bring t ...
, medicinal
alchemy
Alchemy (from Arabic: ''al-kīmiyā''; from Ancient Greek: χυμεία, ''khumeía'') is an ancient branch of natural philosophy, a philosophical and protoscientific tradition that was historically practiced in China, India, the Muslim world, ...
, and the
philosopher's stone
The philosopher's stone or more properly philosophers' stone (Arabic: حجر الفلاسفة, , la, lapis philosophorum), is a mythic alchemical substance capable of turning base metals such as mercury into gold (, from the Greek , "gold", a ...
itself.
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. 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
In physics, the special theory of relativity, or special relativity for short, is a scientific theory regarding the relationship between space and time. In Albert Einstein's original treatment, the theory is based on two postulates:
# The laws o ...
showed that
Maxwell's equations
Maxwell's equations, or Maxwell–Heaviside equations, are a set of coupled partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits.
...
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.
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. One proposed model of
dark energy
In physical cosmology and astronomy, dark energy is an unknown form of energy that affects the universe on the largest scales. The first observational evidence for its existence came from measurements of supernovas, which showed that the univer ...
has been named "
quintessence" by its proponents, in honor of the classical element. 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
Johann II Bernoulli (18 May 1710, in Basel – 17 July 1790, in Basel; also known as Jean) was the youngest of the three sons of the Swiss mathematician Johann Bernoulli. He studied law and mathematics, and, after travelling in France, was for fiv ...
, 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.
This theory of
luminiferous aether
Luminiferous aether or ether ("luminiferous", meaning "light-bearing") was the postulated medium for the propagation of light. It was invoked to explain the ability of the apparently wave-based light to propagate through empty space (a vacuum), so ...
would influence the
wave theory
In historical linguistics, the wave model or wave theory (German ''Wellentheorie'') is a model of language change in which a new language feature (innovation) or a new combination of language features spreads from its region of origin, affecting ...
of light proposed by
Christiaan Huygens
Christiaan Huygens, Lord of Zeelhem, ( , , ; also spelled Huyghens; la, Hugenius; 14 April 1629 – 8 July 1695) was a Dutch mathematician, physicist, engineer, astronomer, and inventor, who is regarded as one of the greatest scientists of ...
, in which light traveled in the form of
longitudinal waves
Longitudinal waves are waves in which the vibration of the medium is parallel ("along") to the direction the wave travels and displacement of the medium is in the same (or opposite) direction of the wave propagation. Mechanical wave, Mechanical l ...
via an "omnipresent, perfectly elastic medium having zero density, called aether". At the time, it was thought that in order for light to travel through a vacuum, there must have been a medium filling the void through which it could propagate, as sound through air or ripples in a pool. Later, when it was proved that the nature of light wave is
transverse
Transverse may refer to:
*Transverse engine, an engine in which the crankshaft is oriented side-to-side relative to the wheels of the vehicle
*Transverse flute, a flute that is held horizontally
* Transverse force (or ''Euler force''), the tangen ...
instead of longitudinal, Huygens' theory was replaced by subsequent theories proposed by
Maxwell,
Einstein
Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theory ...
and
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
The Michelson–Morley experiment was an attempt to detect the existence of the luminiferous aether, a supposed medium permeating space that was thought to be the carrier of light waves. The experiment was performed between April and July 1887 ...
in which evidence for the motion of aether was conclusively absent. The results of the experiment influenced many physicists of the time and contributed to the eventual development of Einstein's
theory of special relativity
In physics, the special theory of relativity, or special relativity for short, is a scientific theory regarding the relationship between space and time. In Albert Einstein's original treatment, the theory is based on two postulates:
# The laws ...
.
Aether and gravitation
![Bernoulli - De gravitate aetheris, 1683 - 1216514](https://upload.wikimedia.org/wikipedia/commons/e/e9/Bernoulli_-_De_gravitate_aetheris%2C_1683_-_1216514.jpg)
In 1682,
Jakob Bernoulli
Jacob Bernoulli (also known as James or Jacques; – 16 August 1705) was one of the many prominent mathematicians in the Bernoulli family. He was an early proponent of Leibnizian calculus and sided with Gottfried Wilhelm Leibniz during the Leib ...
formulated the theory that the hardness of the bodies depended on the pressure of the aether.
Aether has been used in various gravitational theories as a medium to help explain gravitation and what causes it.
![GodfreyKneller-IsaacNewton-1689](https://upload.wikimedia.org/wikipedia/commons/3/39/GodfreyKneller-IsaacNewton-1689.jpg)
A few years later, aether was used in one of Sir
Isaac Newton
Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician, physicist, astronomer, alchemist, theologian, and author (described in his time as a "natural philosopher"), widely recognised as one of the grea ...
's first published theories of gravitation, ''
Philosophiæ Naturalis Principia Mathematica
(English: ''Mathematical Principles of Natural Philosophy'') often referred to as simply the (), is a book by Isaac Newton that expounds Newton's laws of motion and his law of universal gravitation. The ''Principia'' is written in Latin and ...
'' (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.
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.
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.
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
Robert Boyle (; 25 January 1627 – 31 December 1691) was an Anglo-Irish natural philosopher, chemist, physicist, alchemist and inventor. Boyle is largely regarded today as the first modern chemist, and therefore one of the founders of ...
in 1679.
[Newton, Isaa]
"Isaac Newton to Robert Boyle, 1679."
28 February 1679. 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.
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.
See also
*
Akasha
Akasha or Akash (Sanskrit ' ) means space or sky or æther in traditional Indian cosmology, depending on the religion. The term has also been adopted in Western occultism and spiritualism in the late 19th century. In many modern Indo-Aryan la ...
*
Celestial spheres
The celestial spheres, or celestial orbs, were the fundamental entities of the cosmology, cosmological models developed by Plato, Eudoxus of Cnidus, Eudoxus, Aristotle, Ptolemy, Copernicus, and others. In these celestial models, the diurnal m ...
*
Dark matter
Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not ab ...
*
Energy (esotericism)
Proponents and practitioners of various esoteric forms of spirituality and alternative medicine refer to a variety of claimed experiences and phenomena as being due to "energy" or "force" that defy measurement and thus are distinguished from t ...
*
Etheric body
In neo-Theosophy, the etheric body, ether-body, or æther body is the subtle body propounded in esoteric philosophies as the first or lowest layer in the human energy field or aura. The etheric body is said to be in immediate contact with the p ...
*
Etheric force
Etheric force is a term Thomas Edison coined to describe a phenomenon later understood as high frequency electromagnetic waves—effectively, radio. Edison believed it was the mysterious force that some believed pervaded the ether.
At the end o ...
*
Etheric plane
The etheric plane (see also ''etheric body'') is a term introduced into Theosophy by Charles Webster Leadbeater and Annie Besant to represent the subtle part of the lower plane of existence. It represents the fourth ighersubplane of the physical ...
*
*
Prana
In yoga, Indian medicine and Indian martial arts, prana ( sa2, प्राण, ; the Sanskrit word for breath, " life force", or "vital principle") permeates reality on all levels including inanimate objects. In Hindu literature, prāṇa is ...
*
Radiant energy
Radiant may refer to:
Computers, software, and video games
* Radiant (software), a content management system
* GtkRadiant, a level editor created by id Software for their games
* Radiant AI, a technology developed by Bethesda Softworks for ''The ...
References
Footnotes
Citations
{{Reflist, 30em
Aether theories
Classical elements
Energy (esotericism)
Esoteric cosmology
History of science
Mythological substances
Theories in ancient Greek philosophy
es:Éter (física)
fr:Éther (physique)