Rothwell Bronrowan physbron@t-online.de The history of recent physics, by which I refer to the past 120 years give or take ten, has been deeply influenced by a theory separately proposed in the late 1880s and early 1890s by the Irish physicist George Francis FitzGerald (1851-1901) and the Dutch mathematician and physicist Hendrik Antoon Lorentz (1853-1928). This is the theory of length contraction. The theory has it that the length of a body travelling in space shortens along the direction of motion, and that this shortening increases with the increasing velocity of the body up to a maximum speed equal to (almost) c, the speed of light, at which speed the body will be effectively flat. Many people take the view that that we can never know whether length contraction exists or not, since our rulers are also said to expand and shrink along the line of motion of our planet. And since we are therefore unable to measure any difference, how can we ever know? In this paper I will propose a test for length contraction. I will also show, on the basis of a previous proposal, that the concept is not as straightforward as many people think. Length contraction is one of the pillars of relativity. It was the starting point from which Lorentz went on to develop his Lorentz translations, which in turn gave rise to other pillars of relativity - time dilation, mass increase and frames of reference. This makes it an important theory. It is also a theory associated with much confusion. Initially derived solely to compensate for the zero result of the famous Michelson- Morley experiment - which was conducted to verify the existence of the ether, but failed to do so - length contraction was an attempt to save the ether theory, in which both FitzGerald and Lorentz believed. A short time later it was taken over by Einstein, who integrated it in his own calculations. Einstein saw no need for the ether, however, which he simply dismissed. In other words, the theory that length contraction was initially intended to save was dismissed, but the argument proposed solely to defend this theory was kept! 21.09.10 1 (5)
Within the past ten years other scientists have published works claiming that the Michelson-Morley experiment did not record a zero result, i.e. that it did effectively prove the existence of the ether. This removes the very need for the proposal of length contraction in the first place. And yet, a number these scientists 1 also integrate length contraction into their own theories. The test suggested here is not my first attempt to provide evidence for or against length contraction. In an earlier paper 2 I proposed a method of testing for it by comparing the distances between the earth and the moon, a) when the planets are travelling such that an imaginary line joining their centres is at an angle of 90 to their direction(s) of motion, and b) when this imaginary line coincides with their direction of motion. In the situation described under "a)", there would be no contraction along the imaginary line, whereas under "b)" there would, the latter case implying that, since the planets were contracted, the distance separating them would be greater. The contraction effect would have increased the distance between their surfaces by at least 4 cm (probably much more), which - given the current accuracy of earth-moondistance measurements of 2.5 cm - would have been measurable. Planets, however, are not solid bodies as such, but are effectively mixtures of different materials which cannot be expected to contract such that this contraction would be passed on to the planet surfaces. This is explained in the following illustrations. Fig. 1 1 Professor Reginald T. Cahill and Victor V. Demjanov, for example. 2 An Experiment for Length Contraction, Rothwell Bronrowan, the General Science Journal, 14.06.10, CORRECTED ON 27.08.10. 21.09.10 2 (5)
Fig. 2 Fig. 1 shows the "normal" particles making up the planet, whereas Fig. 2 depicts them contracted. In the latter case only a part of the contraction will be evident at the surface of the planet, since further contraction will be prevented due to contact with neighbouring particles. This becomes still clearer in the following two illustration: Fig. 3 Fig. 4 Fig. 3 shows "normal" particles at the surface of the planet in contact with each other, while Fig. 4 shows the same particles under contraction. Because of the contact still existing between them, any contraction would tend to take place on the central (here 21.09.10 3 (5)
vertical) axis of the particles. This implies that the contraction would be both outwards and inwards, creating "hollows" within the planets and minimizing the contraction effect at their surfaces. This in turn raises the question as to what types of solid objects are subject to length contraction. The "contracting" arm in Michelson's experiment was made of brass. This at least has to be seen as contractible, since otherwise the whole argument for length contraction, as developed by Lorentz, becomes invalid. That the proverbial "spaceship" often referred to in length-contraction arguments would itself be contractible, by contrast, seems highly unlikely. At any rate, another experiment must now be found. A new experimental setup is therefore outlined in the following illustration:! Conductor Current Brass Frame Support Fig. 5 Fig. 5 shows the sectional front elevation of an experimental setup that is theoretically capable of detecting any length contraction. This has two identical solid brass objects, each consisting of one spherical end extending into a rod which ends at the opposite side in a sectional T-shape. All three of these components (sphere, rod and T) are actually round. The brass objects are housed in a nonconducting frame with two ball bearings (shown in pink) for further support. Current (shown in red) is passed through a conductor (shown in green) to the brass rods and can only travel further by passing through the brass object to the conducting material on the inside of the frame, which transports it back through the interior of the frame to a measuring device above (not shown). The level of contact between surfaces of the brass "T-sections" and the interior conductor material is variable (perhaps on the basis of various sizes of feathered ball bearings or feathered pins) and depends on the pressure acting on these sections in the direction of the conductor material, i.e. the greater the pressure the greater the contact and the higher the current flow. To establish this pressure the entire setup is rotated. The pressure level can then be adjusted by altering the speed of rotation. 21.09.10 4 (5)
The idea behind the experiment is that, once a sensitive speed of rotation (preferably as low as possible) has been found, length contraction effects should be traceable in the form of increased current flow every time the brass elements are in line with the direction of motion of the earth, since in this position they will exhibit maximum contraction, this increasing the pressure of the "T-sections" on the conductor material. The spherical "weighted ends" are intended to ensure that any momentum effects will tend to further enhance current flow, rather than reduce it. No significant current differences associated with a specific direction of motion would suggest no length contraction. Any such zero result would require further testing of the sensitivity of the device - e.g. by using magnets as substitutes for direction of motion - to ensure that an external effect of similar magnitude can be recorded. The use of brass is only proposed because this was the material used by Michelson. A better alternative in terms of conduction, etc. need not be excluded on this basis. The experiment would probably be best performed in a vacuum. This paper is a call for experimentation to verify or disprove length contraction. It takes the view that, if it is possible to test for it, we should do so instead of continuing to discuss the matter inconclusively for a further hundred years. The experimental setup suggested here is just one proposal. * 21.09.10 5 (5)