Nexus - 1405 - New Times Magazine-pages

Page Content (OCR)

thinking emerged. One claimed that the Earth traverses an the "speed = distance / time" constant under all conditions. The immovable sea of aether, another that the aether is carried along answer was a surprising formula, where lengths shrink and time with the Earth, and a third held that the aether is in motion. goes slower by the same factor. When he divided shrinking Discussions broke out between the schools, showing a need to lengths by slowed-down time, the result was "c", confirming the prove who was right, but proofs rested on technical means and no constancy of the speed of light. reliable mechanical instruments were available until the 1880s This was not, however, a mere mathematical trick to save the when Professor Albert Michelson (1852-1931) from Case day: Lorentz firmly believed that physical shrinking really took University, Cleveland, USA, built his one-millionth-part-accurate place. The material "bolts and wheels explanation" was that interferometer. Such an instrument could identify differences matter consists of atoms and that the radius of atoms is between two arriving light waves in terms of geometrical determined by the size of the orbit of the outer electrons—later interference patterns—that is, patterns formed when beams of called the "Bohr radius". When atoms of matter speed through light hit the same spot, either amplifying each other or weakening the immutable aether, electrons experience an aether-resistance each other depending on whether they arrive at the same time or _and their orbits get compressed so that they are no longer circular slightly out of phase. but elliptical, with the shorter axis in the direction of movement. The idea behind the famous Michelson—Morley experiment was __ The shortening of the axis is calculated by the Lorentz formula for to send two beams of light along two different paths, equally long shrinking.’ as measured by earthly measuring sticks, the only difference In practical terms, what Lorentz was saying was that being their direction—one path being along the movement of the Michelson's steel interferometer had experienced a minute Earth through the "sea of aether", the other traversing the Earth's shrinking in the direction of the Earth's movement through the path. By mirrors and prisms, the two light beams would then be aether. Thus light beams travelling along this axis had a shorter made to meet at the same spot. If those light waves travelling way to go, and since c = distance / time, c appeared to be constant along the path of the Earth got an extra speed through the aether _since time had slowed down by the same factor as the length had sea and those traversing the path were shrunk. not influenced, they would arrive at Suddenly it could be explained to different moments, provided that the the moving scientist why he would aether waves we call light had . . measure the same speed of light as one different speeds in different directions By the 1930s, Einstein had who was floating ina stationary Thus the observer would see a become a household name, spaceship in the aether. But is this weakening of the light as the waves what was proved? Was there any truly arrived at different moments to create and journalists became cosmic, motionless aether, or was it an negative interference—somewhat like interested in how he had entrained aether that travelled with the waves on the sea arriving out of order, 8 solar system? Or what was going on? creating weaker waves compared to come upon his ideas. Later, French mathematician Henri those that roll in at the same time, Poincaré (1854-1912) started to see marching in order, so to speak. things differently: maybe it was a case Michelson acted according to this of how we view this world. Many theory, being a true believer in the static baptised this viewpoint the aether, and his contention was that this static aether penetrated all Lorentz—Poincaré Theory of Relativity. objects, heavy and light, and would in turn influence the speed of the propagating light waves as described above. To test this idea, A Patent Solution? he set up his interferometer in the basement of the university In 1905, a patent clerk by the name of Albert Einstein, working building in an attempt to see if there was any difference between a at the Swiss Patent Office in Bern, sent three articles to the light beam parallel to the movement of the Earth and one German journal Annals of Physics concerning Brownian perpendicular to it. Michelson and his colleague Edward Morley movements (movements of particles in water), the photoelectric (1838-1923) figured that the light beam going against the effect and the zero-result experiment of Michelson and Morley. movement of the Earth would be slowed down, the one going with The latter came to be known as the Special Theory of Relativity. the Earth would be speeded up, while the one traversing the Einstein didn't bring much that was new into the aether discussion direction of the movement of the Earth would be unaltered. They with his theory, except for two new postulates that he hoped could reckoned that these differences should be detectable down to one kill the whole aether controversy: (1) the speed of light is a in a millionth of a wavelength of light. After just 36 universal constant, take it or leave it; (2) there is no such measurements over a period of three days, Michelson and Morley movement as absolute speed relative to a universal, resting aether, declared that there were detectable differences, but not great thus all movement is just a measurement of difference in speed enough to support the theory of a static aether.’ This was later to between moving bodies. From these two initial postulates, it was be known as the famous "1887 zero- result experiment"—but did _ possible to arrive at the Lorentz transformations as a consequence it really produce zero result, and what did it prove or not prove? of how we observe things." Deu tha 102M. Din nm hod ha hald nama and By the 1930s, Einstein had become a household name, and journalists became | interested in how he had A Patent Solution? In 1905, a patent clerk by the name of Albert Einstein, working at the Swiss Patent Office in Bern, sent three articles to the German journal Annals of Physics concerning Brownian movements (movements of particles in water), the photoelectric effect and the zero-result experiment of Michelson and Morley. The latter came to be known as the Special Theory of Relativity. Einstein didn't bring much that was new into the aether discussion with his theory, except for two new postulates that he hoped could ill the whole aether controversy: (1) the speed of light is a universal constant, take it or leave it; (2) there is no such movement as absolute speed relative to a universal, resting aether, thus all movement is just a measurement of difference in speed between moving bodies. From these two initial postulates, it was ossible to arrive at the Lorentz transformations as a consequence of how we observe things." By the 1930s, Einstein had become a household name, and journalists became interested in how he had come upon his ideas. In traditional Einsteinian style, he claimed that he did so on a urely philosophical b "Physics constitutes a logical system of thought which is in a state of evolution, whose basis principles] cannot be distilled, as it were, from experience by an inductive method, but can only be arrived at by free invention. The justification [truth content] of the system rests in the Shrinking Science Great minds were at a loss, since neither the entrained aether (aether that moves with the Earth) nor the static aether was properly proved. In 1892 Hendrik Lorentz (1853-1928), one of the proponents of the static aether theory, suggested a way to explain the zero-result experiment. He asked what it would take in the change of distance travelled by light to keep the formula for 44 = NEXUS come upon his ideas. www.nexusmagazine.com AUGUST - SEPTEMBER 2007