Item #1011 Influence of Motion of the Medium on the Velocity of Light; in The American Journal of Science. Albert Morley Michelson, Edward, and.
Influence of Motion of the Medium on the Velocity of Light; in The American Journal of Science
Influence of Motion of the Medium on the Velocity of Light; in The American Journal of Science

Influence of Motion of the Medium on the Velocity of Light; in The American Journal of Science

New Haven: The American Journal of Science, 1886. First Edition. Wrappers. 1st edition, 1st printing, 2nd issue (preceded by the individual May 1886 issue) of The American Journal of Science, Vol. XXXI, January to June, the full semiannual volume, containing (pages 377–386) the first experiments with Michelson’s own invented instruments, the continuation of which (in 1887), negated classical scientific theories on the existence of a universal ether. The findings held revolutionary implications that led directly to (and through) Lorentz (the Lorentz contraction equations) and Einstein (special relativity), to the acceptance of new reference standards of time and space from geometry and cosmometry (measurement of the universe). Michelson won his 1907 Nobel Prize in physics, both for creating the instruments he used, and for his achievements with them, in his experiments. Original wrappers, covers, spine and page edges brittle and chipped, internally clean, pages unopened, very good. Scarce. No copies on RBH. Very good. Item #1011

Michelson and Morley first aether-drag experiment. “Starting in 1885, Michelson collaborated with Edward Morley, spending considerable time and money to repeat the Fizeau experiment on Fresnel’s drag coefficient (finished in 1886, explained in this paper) and to repeat the Michelson experiment (finished in 1887)... In 1886, Michelson and Morley successfully confirmed Fresnel’s drag coefficient – this result was also considered as a confirmation of the stationary aether concept. This strengthened the hope of finding the aether wind. Thus Michelson and Morley created an improved version of the Michelson experiment with more than enough accuracy to detect this hypothetical effect. The experiment was performed in several periods of concentrated observations between April and July 1887” (Landmark Experiments in Physics).

The Michelson-Morley experiment is one of the most famous and important experiments in the history of physics - the result of which “held revolutionary implications which led directly through Lorentz and Einstein to the acceptance of new standards of reference of time and space from geometry and cosmometry” (Dibner). “In 1729 James Bradley reported to the Royal Society that in observing any fixed star it was necessary to point the telescope not directly at the star but a little in advance of it. This he called the angle of aberration. The fact reported by Bradley was repeatedly confirmed and the angle of aberration was accounted for by the movement of the earth through the ether - the medium by which light waves are conveyed. If the luminiferous ether is a medium through which the earth moves without disturbing it, it would seem to follow that a beam of light reaching the earth from the direction towards which the earth itself is moving should reach it faster than one from an opposite direction. In August 1881 Albert Abraham Michelson described, in the American Journal of Science, a new interferometer which he had devised with the express purpose of measuring these relative speeds with minute accuracy. Any form of clock hitherto invented, however accurate, would necessarily be subject to margin of error greater than the time difference in question. Michelson’s instrument was planned to measure the relative speeds of light waves moving at right angles to each other. In August [recto November] 1887, in the same journal, in collaboration with Edward Williams Morley, he reported the almost completely negative results of their experiments.” (PMM 378). “They used a slightly silvered glass set angular to a ray of sunlight so that a part of the ray was transmitted, a part reflected out and again returned, thereby providing two paths, one perpendicular to the other. If drift existed, the superimposed rays would produce interference. None was observed, showing that the earth’s motion did not affect the light’s speed” (Dibner: Heralds of Science, 161). “The [result] of this experiment was a serious blow to classical scientific theories because it cast doubts on the existence of the universal ether which had been a basic principle of, for example, the Newtonian theories of the universe” (PMM 401). “The dilemma appeared inescapable until Lorentz found the solution ... Lorentz assumed the electrical nature of matter and stated that all electrical particles become shortened when in motion along the direction in which the ether drifts. Thus one arm of Michelson’s interferometer would be just sufficiently shorter than the other to reduce the time necessary for light to traverse it and thus to make that time coincident with that of the beam in the transverse arm of the instrument. In 1905 Einstein propounded a special, limited theory of relativity with the express purpose of clarifying the aberration problem, to which end he adopted Lorentz’s theory” (PMM 378). The result of the Michelson-Morley experiment lies at the core of Einstein’s theory of special relativity; “It’s two vitally important, revolutionary conclusions were (1) that ‘it is impossible by any experiment to detect uniform motion relative to the ether’, (2) that energy and mass are equivalent, expressed in the now famous equation e=mc2. This attempt to circumvent the impasse created by the negative results of the Michelson-Morley experiment derived from a kind of neo-Berkeleyism, which made it appear that the material nature of real objects changed in relation to the position of the observer. Thus the logical conclusion of the Lorentz hypothesis is that physical objects change their size, that the duration of any process varies in length according to the observer’s position. … Clearly, then, length, breadth, depth and even time itself are not inherent properties of spatial objects but variables related to the position and motion of a particular observer. … We must give up the idea of taking a God’s eye view of the world. Thus, it had been supposed that the earth must be moving through the luminiferous ether, fixed in absolute space; but experiments had not revealed any such motion. Einstein wrote: ‘According to this theory there is no such thing as a 'specially favoured' (unique) co-ordinate system to occasion the introduction of the ether-idea, and hence there can be no ether drift, nor any experiment with which to demonstrate it’. (PMM 408).

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