A challenge to Einstein.

TOWARD HAYDEN, a professor of physics at the University of Connecticut since 1967,

I is in the final stages of an experiment that may undermine a basic assumption of Einstein's special theory of relativity: that the speed of light is a constant, irrespective of the observer's motion. Hayden claims that the invariant velocity of light has never been demonstrated experimentally, and to dramatize this startling claim, he and Petr Beckmann, professor emeritus of electrical engineering at the University of Colorado, are jointly offering a reward of $2,000 to anyone who can cite a valid optical experiment demonstrating that the speed of light east to west on the Earth's surface is the same as it is west to east (to an accuracy of fifty meters per second). The experiment does not have to be performed, merely cited.

A longtime skeptic about relativity, Beckmann a few years ago proposed a rival theory of physics which, he claims, fits the known facts and explains them much more simply than Einstein's. Before publishing his theory in a book (Einstein Plus Two, 1987) he sent the manuscript to Howard Hayden at Storrs, Connecticut. Hayden's initial reaction was near-disbelief that the velocity of light had not already been demonstrated to be invariant. But eventually he became convinced that Beckmann was right. In 1988, he devised an experimental test of Beckmann's theory. His preliminary results support Beckmann, raising the question whether there are any experimental observations which require relativity theory to explain them.

Toward the end of the nineteenth century, the evidence that light travels in a wave became overwhelming. Just as sound waves need air to travel in, so light would need a medium, if it traveled in waves. This hypothetical medium was called the ether, and a famous experiment by Michelson and Morley, performed in Cleveland in 1887, was expected to demonstrate its existence. Since the Earth must be passing through this ether on its journey around the sun, everyone assumed it would be possible to detect the ether wind" with a suitable apparatus, just as it is possible to detect the air from a moving car by putting your hand out into the breeze. In the 1880s Michelson devised an experiment sensitive enough, in theory, to produce a measurable effect.

But no matter how many times they tried, Michelson and Morley could detect no ethereal breeze. (In their experiment, this had been expected to take the form of a shift in the interference pattern visible where criss-crossing light rays came together.)

Various explanations for the null result were suggested. Michelson himself supposed that the ether was "entrained," which is to say carried along with the Earth. As we shall see, this may have been a close approximation to the truth. But the entrained-ether theory was rejected by most scientists. The physicists G. F. FitzGerald and H. A. Lorentz suggested another possibility: that moving objects contract slightly in the direction of motion-the contraction being just sufficient to account for the null result. This was ingenious, but unsatisfactory. It had the ad-hoc look of an unfalsifiable assumption, rather like the suggestion that everything in the universe is getting bigger at the same time.

Then in 1905, in his special theory of relativity, Einstein suggested a third way of looking at the matter. He proposed a) that the speed of light is the same in all directions, irrespective of the motion of any apparatus set up to measure it; and b) that observers traveling with different velocities would see the same things with different lengths and durations. This eliminated the need for an ether altogether. Einstein's famous paper showed that everything could be worked out mathematically if these peculiar assumptions about the universe were made.

This was a very odd procedure. Einstein bent" space and time so that a velocity could be preserved as a constant. But velocity itself is merely distance divided by time. Discarding space and time as "absolutes" so that a velocity can be retained as an absolute is as strange as it would be for a man to go on living undisturbed on the second floor of his house while the basement and ground floor were completely remodeled.

Einstein's assumption about the invariant velocity of light emerged from the turn-of-the-century quandary of physicists trying to account for the Michelson-Morley result. But if it turns out that there is a simpler way of explaining what really happened, we should, out of deference to the simplicity that is preferred by science, discard the premise that the speed of light is invariant. We should (everything else being equal) prefer the notion that light behaves like other wave phenomena (such as sound). This would allow us to bring back space and time as absolutes. And it would, to a large extent, restore the classical world view of Isaac Newton.

What, then, is Beckmann's theory, and does it indeed achieve such a degree of simplification?

Beckmann argues that the medium through which light waves travel (or more generally, electromagnetic waves) is not a universal, all pervasive, uniform substance-the ether-but more simply the local gravitational field. For us, the local" gravitational field is overwhelmingly that of the Earth. And this field moves forward with the Earth on its journey around the sun. The null result obtained by Michelson-Morley is therefore easily explained because there was no "ether wind" to measure. Analogously, someone in the bathroom of a Boeing 747 would not expect to feel a slipstream if he stuck his head out into the main cabin. The air in the main cabin is moving along with him.

Plot Twist

AT THIS POINT Beckmann adds a plot twist-almost literally. The Earth is also rotating on its axis every 24 hours, and there are good reasons for believing that the Earth really does rotate within its gravitational field; that is, that this field does not twist around with the Earth. Beckmann illustrates this key point with the following analogy:

Imagine a woman wearing a hoop skirt fitting loosely around her waist. As she moves forward, the skirt moves with her and there is no relative motion between her and the skirt. But if she then pirouettes, or does the twist, while still moving forward, she would rotate" within the skirt. At that point relative motion between her body and the skirt would be detectable.

The Earth moves forward around the sun at about sixty thousand miles per hour; but it rotates on its axis (in the latitude of New York) at only about six hundred mph. If Beckmann is right, therefore, the detectable relative motion between the rotating Earth and its gravitational field is only about one-hundredth of what Michelson and Morley were looking for. But the relevant equation requires that this fraction be squared, and so the expected "fringe shift" is only oneten-thousandth of what they expected to find. This was beyond the technical limits of measuring instruments in the 1880s. But today it can be measured.

Readers at this point may well be imagining that Howard Hayden has simply redone Michelson-Morley, looking for this much smaller effect. In fact, such an experiment would be very expensive for someone without the necessary equipment. Instead, Hayden has repeated another old experiment, first performed at Cambridge in 1903 by Trouton and Noble; an experiment sometimes called the electromagnetic equivalent of Michelson-Morley.

It cannot easily be explained, but it involves suspending a capacitor from a very thin copper wire, the whole apparatus being carefully protected in a vacuum and shielded from stray currents and magnetic influences. If the Earth's surface is, as claimed, moving through the Earth's gravitational field west to east at six hundred mph, and if this field really is the medium in which electromagnetic waves travel, the suspended capacitor should experience a torque, slowly twisting in the "ether wind" until the capacitor is aligned north-south. If, on the other hand, Einstein is right, and the velocity of electromagnetic waves is an absolute regardless of the gravitational field, there should be no torque. Hayden has detected a torque, as Beckmann predicted.

Four additional points should be borne in mind:

No Einstein's famous equation, E = MC.sq.2], expressing the relationship between mass and energy, is unaffected by all this. It was derived independently of relativity theory (some textbooks and popularizations to the contrary notwithstanding) and would be unaffected by its demise.

IF The most famous experimental test of Einstein occurred in 1919, when an expedition photographed a solar eclipse off West Africa and confirmed the truth of a new theory of the universe," according to the opening page of Paul Johnson's Modern Times. Light rays from a star bent slightly, as predicted, as they passed close by the sun. But according to Beckmann and Hayden, this can easily be explained without relativity. Light rays do bend when they pass through a medium of varying density; they bend sharply, as anyone can see by looking at a pencil in a glass of water, when passing from one medium to another. Likewise, but to a much smaller extent, light rays passing from the rarefied medium of gravity in outer space into the denser gravitational field nearer the sun should be expected to bend. Classical physics (Fermat's Law) is sufficient to explain it; Einsteinian complexity, such as curved space is not needed. (Fermat's Law states that light en route from A to B follows the path that minimizes the time of transit.)

Another much-heralded confirmation of Einstein is the small discrepancy between the advance of Mercury's perihelion (the orbital point closest to the sun) and the result predicted by Newton. "Einstein's theory accounted exactly for this residue," Bertrand Russell wrote in The ABC of Relativity. Beckmann is astounded by the rewriting of history here. Einstein's formula explaining Mercury's orbit, published in 1915 and derived from general relativity theory, had in fact been published 17 years earlier by a man named Paul Gerber (Beckmann believes he was a high-school teacher in Stargard, Germany). Gerber used classical physics, plus the assumption that gravity is not instantaneous (as Newton thought) but propagates with the speed of light (as is now generally accepted). Gerber derived Einstein's equation exactly, without relativity. Einstein arrived at the same point using a complex trick-bag of gravitational tensors and Riemannian geometry. The protocols of science recommend that simpler explanations should be preferred to complex ones, but Gerber has been ignored.

Albert Michelson, the first American to win the Nobel Prize in physics, never accepted the theory of relativity. (Nor did H. A. Lorentz.) Michelson believed that the ethel?' he failed to detect was entrained by the Earth in its orbit, but not in its rotation. In 1925 he checked this theory, so similar to Beckmann's, in an elaborate optical experiment at Clearing, Illinois, with a colleague at the University of Chicago, H. G. Gale. They did indeed find a fringe shift, which Einstein had to explain by a highly complicated application of general relativity theory. But by then Einstein was well on his way to deification, and today MichelsonGale is rarely mentioned.

What is now needed is a rerun of the Michelson-Morley experiment, with the Beckmann theory put to the test. The famous experiment was repeated by physicists at the University of Colorado in 1979, on a rotating table and using laser light. Unexpected perturbations were detected, but attributed to other causes. One of the experimenters, Dr. John L. Hall of the Joint Institute for Laboratory Astrophysics, a leading expert on speed-of-light experiments, says that Beckmann "has made a serious effort to reduce relativity thinking to an objective environment, in which measurements can be made and his theory put to the test." He has suggested that Michelson-Morley should be repeated on an orbiting satellite.

The experiment would be crucial because, if Beckmann is correct, the much greater velocity with which a satellite passes through the Earth's gravitational field (a satellite's day" is ninety minutes) would increase by a factor of four hundred the fringe shift that Beckmann would expect to find. "Such an experiment would not prove that Beckmann is right," Hall added, but it sure could prove that he is wrong." By the same token, it could also prove that Einstein is wrong. Let's hope that Hall gets the opportunity to do the experiment.

* NB: Those who would like to try to collect the $2,000 reward can reach Beckmann at: P.O. Box 251, Boulder, Colo. 80306; and Hayden at: Physics Department, Storrs, Conn. 06269. Incidentally, Beckmann publishes Galileian Electrodynamics, a bi-monthly journal on the topics raised herein.