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SCIENCE BY DEMOCRACY?
To The Editor:
I was very interested in that the participants and news reporters felt it necessary to mention who won and lost at the AAAS Symposium. I did not know that scientific facts and theories were subject to the democratic process.
G. Henry Koether III
THE VELOCITY OF LIGHT IN RELATION TO MOVING BODIES
To The Editor:
My attention has been directed from more than one quarter to the articles in Pensée (1) by Immanuel Velikovsky entitled "The Velocity of Light in Relation to Moving Bodies" and "A Missed Opportunity?"—the first written several years ago, proposing an experimental test of the special theory of relativity, and the second concerning the problem of testing the general theory. While I found these extremely interesting, I did not at first intend commenting on them, being too fully engaged with my own independent controversy concerning special relativity, leading to and arising from my book, Science at the Crossroads (2). However, on reflection, Velikovsky's suggested experiment seems to me to bring to light a hidden assumption, of a very fundamental character, which his experiment—with some probably simple modifications—would serve to test. In brief, it is this. Velikovsky, like everyone else, assumes that at sunrise and sunset an observer on the Earth and a point at the centre of the Sun's disc are in relative motion along the line of sight. But that is true only if the Earth's rotation is absolute, which the general postulate of relativity denies. Hence, a test whether such relative motion actually exists, either by Velikovsky's experiment or (probably more easily, but I am insufficiently acquainted with the possibilities of the most modern equipment to judge of this; the necessary observations may, in fact, exist, without this particular significance of them having been realized) by looking for Doppler shifts, would give an almost, if not quite, final decision on the truth of the general relativity postulate.
The point is this. There is an undoubted fact of observation which may be expressed in either of the following ways: 1) The Earth rotates on its axis once a day while the direction of the Sun remains approximately constant. 2) The Earth does not rotate but the Sun travels round it once a day. The general relativity postulate asserts that these are two equivalent and (apart from convenience) equally valid descriptions of the same phenomenon, no observation being possible that could distinguish between them. Therefore, if such an observation were made, the general relativity postulate would be disproved. According to expression 1), opposite spectrum shifts will be observable at sunrise and sunset. According to expression 2), however, the Sun moves across the line of sight on each occasion, and no such spectrum shifts will be observed: the spectra at sunrise and at sunset will be in the same position (apart, of course, from negligible secondary effects).
There is no question about the requirement of general relativity according to Einstein's account of it in his original paper (3). In the first three paragraphs, from which, he says, "we shall be led to a theory of gravitation," he chooses rotation as the particular example of accelerated motion which, he claims, cannot be ascribed uniquely to either of the two bodies possessing such motion relatively to one another, "except when observable facts ultimately appear as causes and effects." It is inescapable, therefore, that if the general relativity postulate (which is the basis of what is generally called the general relativity theory, which includes Einstein's theory of gravitation) is true, whatever is observed in the light from the Sun at sunrise and sunset must be expressible equally validly in the forms 1) and 2).
Any hypothesis, of course, can be saved if one is prepared to make whatever additional ad hoc hypothesis is needed to save it, but I think that if observation showed the spectrum shifts that would naturally follow from expression 1), the only reasonable conclusion would be that the general postulate of relativity (so far as rotation is concerned, but not necessarily accelerated translational motion) would be untenable. To save it we should have to postulate, quite arbitrarily, "gravitational" effects of a revolving Sun (or universe) astonishingly identical in quality and quantity with those required by the supposition of a rotating Earth according to the Doppler principle. Such freedom of expression would reduce science to a farce. On the other hand, if observation showed no spectrum shift at sunrise or sunset, there would similarly be no reasonable alternative to a return to Ptolemaic astronomy.
It is therefore much to be hoped that this observation, if not already made, will be made as soon as possible. To test the special relativity theory, however, Velikovsky's experiment, involving an actual measurement of velocity instead of a spectrum shift, would be necessary, for the latter (assuming the absolute rotation of the Earth) would be expected on both the Galilean and Einsteinian formulae for composition of velocities. (It must be remembered, however, that while disproof of the latter would destroy the special relativity theory, a verification of it would not necessarily confirm that theory, for it would be consistent also with Lorentz's quite different theory.) It is therefore to be hoped also that Velikovsky's experiment, in principle at least, will be attempted. I have, however, some reservations concerning its details, though these might be easily removable.
First, I am not sure that the remarks concerning the effect of the result on Ritz's hypothesis are justified, since Ritz's statement seems to me ambiguous. However, that is of secondary importance. The essential thing is to determine whether the velocity of light is constant with respect to its source or to a universal "ether" irrespective of the motion of the source, and the experiment could be made to test this point. But sunlight contains light of all colours which, according to present views, have different velocities in a refracting medium such as air. If the terrestrial light is monochromatic, a filter would be needed near the slit to select the same colour from the sunlight, and we cannot assume that this would not affect the velocity of the light from the Sun. We must avoid all assumptions about the mechanism of transmission of light through a transparent medium (as well as that of reflection, though in this case the reflection would be too near the end of the journey to be important), and it might well be that the light emerging from the filter would have velocity o with respect thereto, with whatever velocity it entered. In any experiment in which the special relativity theory is on test, the present electromagnetic theory of light must be regarded as on test also, and no assumptions depending on it can be made.
Probably, however, the experiment could be modified to avoid uncertainties of this kind, and, if so, it should certainly be made.
1. I. Velikovsky, Pensée 3 (Fall, 1973): 17-19.
2. H. Dingle, Science at the Crossroads (London: Martin Brian & O'Keefe, 1972).
3. A. Einstein, Ann d. Phys. 19 (1916 ): 769.
"SYMPOSIUM OF CHARLATANRY"
We received the following letter prior to the McMaster University symposium, "Velikovsky and the Recent History of the Solar System." Ed.
To The Editor:
Your suggestion that I should participate in a symposium of charlatanry is insulting. Please do not bother me any more with any of your material.
H. K. Eichhorn-von Wurmb
To The Editor:
I believe that Peter Smith in his "News and Views" article in Nature (Vol. 249, p. 511), "Does the Geomagnetic Field Affect Climate," may be inaccurate when he states, "de Vries seems to have been the first to propose a correlation between radiocarbon activity and climatic changes." See the section "Clock Unwound," in I. Velikovsky's Earth in Upheaval.
PENSEE Journal VIII