Timeline of luminiferous aether - AbsoluteAstronomy.com

The timeline

Timeline

A timeline is a way of displaying a list of events in chronological order, sometimes described as a project artifact . It is typically a graphic design showing a long bar labeled with dates alongside itself and events labeled on points where they would have happened.-Uses of timelines:Timelines...

of luminiferous aether
Luminiferous aether
In the late 19th century, luminiferous aether or ether, meaning light-bearing aether, was the term used to describe a medium for the propagation of light....

begins in the late 19th century with the concept of luminiferous aether ("light-bearing aether

Luminiferous aether

In the late 19th century, luminiferous aether or ether, meaning light-bearing aether, was the term used to describe a medium for the propagation of light....

"), or ether, as a medium

Transmission medium

A transmission medium is a material substance that can propagate energy waves...

for electromagnetic

Electromagnetic radiation

Electromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...

propagation. The aether was assumed to exist

Existence

In common usage, existence is the world we are aware of through our senses, and that persists independently without them. In academic philosophy the word has a more specialized meaning, being contrasted with essence, which specifies different forms of existence as well as different identity...

for much of the 19th century—until the Michelson-Morley experiment

Michelson-Morley experiment

The Michelson–Morley experiment was performed in 1887 by Albert Michelson and Edward Morley at what is now Case Western Reserve University in Cleveland, Ohio. Its results are generally considered to be the first strong evidence against the theory of a luminiferous ether and in favor of special...

returned the famous "null result". Further experiments were in general agreement and by the 1920s the aether was mostly assumed not to exist.

Early experiments

4th-century BC – Aristotle

Aristotle

Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...

publishes Physics
Physics (Aristotle)
The Physics of Aristotle is one of the foundational books of Western science and philosophy...

. He was one of the first to publicly hypothesize as to the nature of light, proposing that it was a disturbance in the element air, hence it was a wave-like phenomenon.

1704 – Isaac Newton

Isaac Newton

Sir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...

publishes Opticks
Opticks
Opticks is a book written by English physicist Isaac Newton that was released to the public in 1704. It is about optics and the refraction of light, and is considered one of the great works of science in history...

, in which he proposes a particle theory of light. This had trouble explaining refraction

Refraction

Refraction is the change in direction of a wave due to a change in its speed. It is essentially a surface phenomenon . The phenomenon is mainly in governance to the law of conservation of energy. The proper explanation would be that due to change of medium, the phase velocity of the wave is changed...

, so he adds a "fudge factor", claiming that an "Aethereal Medium" is responsible for this effect, and going further to suggest it might be responsible for other physical effects such as heat

Heat

In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...

1727 – James Bradley

James Bradley

James Bradley FRS was an English astronomer and served as Astronomer Royal from 1742, succeeding Edmund Halley. He is best known for two fundamental discoveries in astronomy, the aberration of light , and the nutation of the Earth's axis...

measures stellar aberration for the first time, proving (again) that light has a finite speed as well as that the Earth is moving.

1818 – Augustin Fresnel introduces the wave theory of light, which proposes light is a transverse wave travelling in an aether, thereby explaining how polarization can exist. It is important to note that both Newton's particle theory and Fresnel's wave theory both assume an aether exists, albeit for different reasons. From this point on, no one even seems to question its existence.

1820 – Discovery of Siméon Poisson's "Bright Spot", supporting the Wave Theory.

1830 – Fresnel develops a formula for predicting and measuring aether dragging by massive objects, based on a coupling constant. Such dragging seems to be at odds with aberration however, which would require the Earth not to drag the aether in order to be visible.

George Gabriel Stokes

Sir George Gabriel Stokes, 1st Baronet FRS , was an Irish mathematician and physicist, who at Cambridge made important contributions to fluid dynamics , optics, and mathematical physics...

becomes a champion of the dragging theory.

1851 – Armand Fizeau carries out his famous experiment with light travelling through moving water. He measures fringing due to motion of the water, perfectly in line with Fresnel's formula. However he sees no effect due to the motion of the Earth, although he does not comment on this. Nevertheless this is seen as very strong evidence for aether dragging.

1868 – Martinus Hoek carries out an improved version of Fizeau's using an interferometer experiment with one arm in water. He sees no effect at all, and cannot offer an explanation as to why his experiment is so at odds with Fizeau's.

1871 – George Biddell Airy

George Biddell Airy

Sir George Biddell Airy PRS KCB was an English mathematician and astronomer, Astronomer Royal from 1835 to 1881...

re-runs Bradley's experiment with a telescope filled with water. He too sees no effect. It appears that aether is not dragged by mass.

1873 – James Clerk Maxwell

James Clerk Maxwell

James Clerk Maxwell of Glenlair was a Scottish physicist and mathematician. His most prominent achievement was formulating classical electromagnetic theory. This united all previously unrelated observations, experiments and equations of electricity, magnetism and optics into a consistent theory...

publishes his Treatise on Electricity and Magnetism.

1878 to 1880 – Maxwell suggests absolute velocity of Earth in aether may be optically detectable.

1881 – Albert Abraham Michelson

Albert Abraham Michelson

Albert Abraham Michelson was an American physicist known for his work on the measurement of the speed of light and especially for the Michelson-Morley experiment. In 1907 he received the Nobel Prize in Physics...

publishes his first interferometer experiments, using the device for the measurement of extremely small distances.

Hendrik Antoon Lorentz finds Michelson's calculation have errors (i.e., doubling of the expected fringe shift error).

1882 – Michelson acknowledges his interpretation errors.

Crisis

1887 – the Michelson-Morley experiment

Michelson-Morley experiment

(MMX) produces the famous null result. A small drift is seen, but it is too small to support any "fixed" aether theory, and is so small that it might be due to experimental error.

Many physicists dust off Stokes' work, and dragging becomes the "standard solution"

1887 to 1888 – Heinrich Hertz verifies the existence of electromagnetic waves.

1889 – George FitzGerald

George FitzGerald

George Francis FitzGerald was an Irish professor of "natural and experimental philosophy" at Trinity College in Dublin, Ireland, during the last quarter of the 19th century....

proposes the Contraction Hypothesis, which suggests that the measurements are null due to changes in the length in the direction of travel through the aether.

1892 – Oliver Lodge demonstrates that aether drag is invisible around rapidly moving celestial bodies.

1895 – Lorentz proposes independently the Contraction Hypothesis.

1902 to 1904 – Morley and Morley conduct a number of MM experiments with a 100 ft interferometer, producing the null result.

1902 to 1904 – Lord Rayleigh and DeWitt Bristol Brace

DeWitt Bristol Brace

DeWitt Bristol Brace was an US-American physicist who was known for his optical experiments, especially as regards the relative motion of Earth and the luminiferous aether.-Life and work:...

found no signs of double refraction (due to Fitzgerald-Lorentz Contraction) of moving bodies in the aether.

1903 – the Trouton-Noble experiment

Trouton-Noble experiment

The Trouton–Noble experiment attempted to detect motion of the Earth through the luminiferous aether, and was conducted in 1901–1903 by Frederick Thomas Trouton and H. R. Noble...

, based on an entirely different concept using electrical forces, also produces the null result

1905 – Miller and Morley's experiment data is published. Test of the Contraction Hypothesis has negative results. Test for aether dragging effects produces null result.

1908 – the Trouton-Rankine experiment

Trouton-Rankine experiment

The Trouton–Rankine experiment was an experiment designed to measure if the Lorentz–FitzGerald contraction of an object according to one frame produced a measurable effect in the rest frame of the object, so that the ether would act as a "preferred frame"...

, another experiment based on electrical effects, does not detect the Fitzgerald-Lorentz Contraction.

Change

1904 – Hendrik Lorentz

Hendrik Lorentz

Hendrik Antoon Lorentz was a Dutch physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect...

publishes a new theory of moving bodies, without discarding the stationary (electromagnetic) ether concept.

1905 – Henri Poincaré

Henri Poincaré

Jules Henri Poincaré was a French mathematician, theoretical physicist, engineer, and a philosopher of science...

shows that Lorentz's theory fulfills the principle of relativity, and publishes the Lorentz transformations. His model was still based on Lorentz's ether, but he argues that this aether is perfectly undetectable.

1905 – Albert Einstein

Albert Einstein

Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...

publishes an observationally equivalent theory, but complete with a derivation from principles alone (leaving the ether aside). Einstein also emphasized that this concept implies the relativity of space and time. He later labelled it special relativity

Special relativity

Special relativity is the physical theory of measurement in an inertial frame of reference proposed in 1905 by Albert Einstein in the paper "On the Electrodynamics of Moving Bodies".It generalizes Galileo's...

1908 – Trouton-Rankine experiment

Trouton-Rankine experiment

shows that length contraction

Length contraction

In physics, length contraction – according to Hendrik Lorentz – is the physical phenomenon of a decrease in length detected by an observer of objects that travel at any non-zero velocity relative to that observer...

of an object according to one frame does not produce a measurable change of resistance in the object's rest frame

1913 – Georges Sagnac

Georges Sagnac

Georges Sagnac was a French physicist who lent his name to the Sagnac effect, a phenomenon which is at the basis of interferometers and ring laser gyroscopes developed since the 1970s. Sagnac died at Meudon-Bellevue....

uses a rotating MMX device and receives a clearly positive result. The so-called Sagnac effect

Sagnac effect

The Sagnac effect , named after French physicist Georges Sagnac, is a phenomenon encountered in interferometry that is elicited by rotation. The Sagnac effect manifests itself in a setup called ring interferometry. A beam of light is split and the two beams are made to follow a trajectory in...

was considered excellent evidence for aether at the time, but was later explained via general relativity

General relativity

General relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics...

. Good explanations based on SR also exist.

1914 – Walther Zurhellen uses observations of binary stars to determine if the speed of light is dependent on movement of the source. His measurements show that it is not to 10⁻⁶. This is claimed to be additional evidence against aether dragging.

1915 – Einstein publishes on the general theory of relativity

General relativity

General relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics...

1919 – Arthur Eddington's Africa eclipse expedition is conducted and appears to confirm the general theory of relativity.

1920 – Einstein says that special relativity does not require rejecting the aether, and that the gravitational field of general relativity may be called aether, to which no state of motion can be attributed.

1921 – Dayton Miller

Dayton Miller

Dayton Clarence Miller was an American physicist, astronomer, acoustician, and accomplished amateur flautist...

conducts aether drift experiments at Mount Wilson

Mount Wilson (California)

Mount Wilson is one of the better known peaks in the San Gabriel Mountains, part of the Angeles National Forest in Los Angeles County, California. It is the location of the Mount Wilson Observatory and has become the astronomical center of Southern California with and telescopes, and and tall...

. Miller performs tests with insulated and non-magnetic interferometers and obtains positive results.

1921 to 1924 – Miller conducts extensive tests under controlled conditions at Case University.

1924 – Miller repeats his experiments at Mount Wilson and yields a positive result.

Rudolf Tomascheck uses stars for his interferometer light source, getting the null result.

1925 – the Michelson-Gale-Pearson experiment

Michelson-Gale-Pearson experiment

The Michelson–Gale–Pearson experiment is a modified version of the Michelson-Morley experiment and the Sagnac-Interferometer. It measured the Sagnac effect due to Earth's rotation, and thus tests the theories of special relativity and luminiferous ether along the rotating frame of...

produces a positive result while attempting to detect the effect of Earth's rotation on the velocity of light. The significance of the experiment remains debated to this day, but this planetary Sagnac effect is measured by ring laser gyros and taken into account by the GPS system.

1925 April – Meeting of the National Academy of Sciences

United States National Academy of Sciences

The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...

Arthur Compton

Arthur Holly Compton was an American physicist and Nobel laureate in physics for his discovery of the Compton effect. He served as Chancellor of Washington University in St. Louis from 1945 to 1953.-Early years:...

explains the problems with the Stokes aether drag solution.

Miller presents his positive results of the aether drag.

1925 December – American Association for the Advancement of Science

American Association for the Advancement of Science

The American Association for the Advancement of Science is an international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsibility, and supporting scientific education and science outreach for the...

meeting.

Miller proposes two theories to account for the positive result. One consists of a modified aether theory, the other a slight departure from the Contraction Hypothesis.

1926 – Roy J. Kennedy produces a null result on Mount Wilson

Auguste Piccard

Auguste Antoine Piccard was a Swiss physicist, inventor and explorer.-Biography:Piccard and his twin brother Jean Felix were born in Basel, Switzerland...

and Ernest Stahel produce a null result on Mont Rigi.

1927 – Mount Wilson conference.

Miller talks of partial entrainment

Michelson talks about aether drag and altitude differential effects

K. K. Illingworth produces a null result using a clever version of the MMX with a step in one mirror that dramatically improves resolution. The resolution is so good that most partial entrainment systems can be eliminated.

1929 – Michelson and F. G. Pease perform the Pearson experiment and produce a null result.

1930 – Georg Joos

Georg Joos

Georg Jakob Christof Joos was a German theoretical physicist. He wrote Lehrbuch der theoretischen Physik, first published in 1932 and one of the most influential theoretical physics textbooks of the 20th Century.-Education:Joos began his higher education in 1912 at the Technische Hochschule...

produces a null result using an extremely accurate interferometer placed entirely in vacuum.

1932 – the Kennedy-Thorndike experiment

Kennedy-Thorndike experiment

The Kennedy–Thorndike experiment first conducted in 1932, is a modified form of the Michelson–Morley experimental procedure, and tests special relativity....

uses an interferometer with arms of different lengths and not at right angles. They measure over several seasons and record on photographs to allow better post-measurement study. The Kennedy Thorndike experiment becomes one of the fundamental tests for SR, proving the independence of light speed wrt to the speed of the emitting source. The other two fundamental tests are Michelson-Morley experiment

Michelson-Morley experiment

(proves light speed isotropy) and Ives-Stilwell experiment

Ives-Stilwell experiment

The Ives–Stilwell experiment exploits the transverse Doppler effect . This was the first direct, quantitative confirmation of the time dilation factor. Together with the Michelson–Morley and Kennedy–Thorndike experiments, it forms one of the fundamental tests of special relativity theory...

(proves time dilation)

1934 – Georg Joos

Georg Joos

publishes on the Michelson-Gale-Pearson experiment

Michelson-Gale-Pearson experiment

, stating that it is improbable that aether would be entrained by translational motion and not by rotational motion.

1935 – Hammar experiment

Hammar experiment

The Hammar experiment was an experiment designed by Gustaf Wilhelm Hammar to test the aether drag hypothesis.-Overview:In 1903 the Trouton-Noble experiment, and later the Trouton-Rankine experiment in 1908, presented controversial evidence against the theory of a medium for light propagation known...

disproves aether entrainment

1951 – Paul Dirac

Paul Dirac

Paul Adrien Maurice Dirac, OM, FRS was an English theoretical physicist who made fundamental contributions to the early development of both quantum mechanics and quantum electrodynamics...

writes that currently-accepted quantum field theory requires an aether, although he never formulated this theory completely.

Debate slows

1955 – R. S. Shankland, S. W. McCuskey, F. C. Leone, and G. Kuerti performed an analysis of Miller's results and explained them as stemming from systematic errors (Shankland's explanation is now widely accepted).

1958 – Cedarholm, Havens, and Townes use two maser

Maser

A maser is a device that produces coherent electromagnetic waves through amplification by stimulated emission. Historically, “maser” derives from the original, upper-case acronym MASER, which stands for "Microwave Amplification by Stimulated Emission of Radiation"...

s frequency locked to each other and send the light in two directions. They receive the null result. The experiment is not as precise as earlier light-based MMX experiments, but demonstrates a novel setup that would become much more accurate in the future.

1964 Jaseja, Javan, Murray and Townes repeat the earlier experiment with newer and much more precise masers.

1969 – Shamir and Fox repeat the MMX experiment with the "arms" in acrylic glass

Acrylic glass

Poly is a transparent thermoplastic, often used as a light or shatter-resistant alternative to glass. It is sometimes called acrylic glass. Chemically, it is the synthetic polymer of methyl methacrylate...

waveguides and a highly stable laser

Laser

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

as the source. The experiment should detect a shift as small as ~0.00003 of a fringe, and none is measured.

1972 – R. S. Shankland admits he would not likely have given the effort to question Dayton Miller's work had it not been for Albert Einstein's "interest and encouragement."

1973 – Trimmer finds a null result in a triangular interferometer with one leg in glass.

1977 – Brecher repeates Zurhellen's experiment with binary pulsars, showing no difference in light speed to 2*10⁻⁹

1979 Brillet and Hall use the Townes setup with highly accurate lasers, demonstrating no drift to 3 parts in 10¹⁵. Interestingly the experiment also demonstrates a leftover 17 Hz signal, but the authors assume it is linked to the laboratory.

1984 – Torr and Kolen find a cyclic phase shift between two atomic clock

Atomic clock

An atomic clock is a clock that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element...

s, but the distance between is relatively short (0.5 km) and they're clocks of the less-precise rubidium type

1988 – Gagnon et al. measure one way light speed and detect no anisotropy

1990 – Hils and Hall repeat the Kennedy-Thorndike experiment with lasers, taking measurements over the period of a year. They find no shifting in 2 10⁻¹³

Krisher et al., Phys. Rev. D, 42, No. 2, pp. 731–734, (1990) use two hydrogen masers fixed to the earth and separated by a 21 km fiber-optic link to look for variations in the phase between them. They put an upper limit on the one-way linear anisotropy of 100 m/s.

1991 – Over a six-month period, Roland DeWitte finds, over a 1.5 km underground coaxial cable

Coaxial cable

Coaxial cable, or coax, has an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis...

, a cyclic component in the phase drift between higher-precision cesium-beam clocks on more-or-less the same meridian

Meridian (geography)

A meridian is an imaginary line on the Earth's surface from the North Pole to the South Pole that connects all locations along it with a given longitude. The position of a point along the meridian is given by its latitude. Each meridian is perpendicular to all circles of latitude...

; the period equals the sidereal day _{http://www.lns.cornell.edu/spr/1998-12/msg0013719.htmlhttp://www.scieng.flinders.edu.au/cpes/people/cahill_r/HPS16.pdf}

2003 – Holger Mueller and Achim Peters carry out a Modern Michelson-Morley Experiment using Cryogenic Optical Resonators at Humboldt University, Berlin. They find no shifting in 10⁻¹⁵ _{http://link.aps.org/abstract/PRL/v91/e020401}

Classical references

Maxwell, Collected Papers, H. A. Lorentz, Archives Neerlandaises, xxi. 1887, and xxv. 1892
Versuch einer Theorie der electrischen und optischen Erscheinungen in bewegten Korpern (Leyden, 1895)
"Elektrodynamik " and " Elektronentheorie " in the Encyk. der Math. Wissenschaften, Band v. 13, 14
O. Lodge, " On Aberration Problems," Phil. Trans. 1893 and 1897
J. Larmor, Phil. Trans. 1894-95-97, and a treatise, Aether and Matter (1900) p. 262
P. K. L. Drude
Paul Karl Ludwig Drude
Paul Karl Ludwig Drude was a German physicist specializing in optics. He wrote a fundamental textbook integrating optics with Maxwell's theories of electromagnetism.- Education :...

, A. Schuster, R. W., General physics of the aether;
Collected Papers of Lord Rayleigh

External links and references

OCR scan of the aether listing in the 1911 edition encyclopedia page 1 page 2

James DeMeo: "Dayton Miller's Ether-Drift Experiments: A Fresh Look"

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Early experiments

Crisis

Change

Debate slows

Further reading

Classical references

See also

External links and references