[Graybeard]

Einstein ... this is from a 1929 paper by Paul J. Heyl. To me it indicates that time dilation is only apparent. The full paper is in my blog under 'simple science' if you wish to read it all

What do you think of this explanation

P J. Heyl .... 1929
For example, suppose that we, with our instruments for measuring space and time, are located on a platform, which we believe to be stationary. We cannot be altogether certain of this, for there is no visible object in the universe save another similar platform carrying an observer likewise equipped: but when we observe relative motion between our platform and the other it pleases our intuition to suppose our platform at rest and to ascribe all the motion to the other.


Einstein asserts that if this relative velocity were great enough we might notice some strange happenings on the other platform. True, a rather high velocity would be necessary, something comparable with the speed of light, say 100,000 thousand miles a second; and it is tacitly assumed that we would be able to get a glimpse of the moving system as it flashed by. Granting this, what would we see?

Einstein asserts that if there were a circle painted on the moving platform it would appear to us as an ellipse with its short diameter in the direction of its motion. The amount of this shortening would depend on the speed with which the system is moving, being quite imperceptible at ordinary speeds. in the limit, as the speed approached that of light, the circle would flatten completely into a straight line - its diameter perpendicular to the direction of motion.

Of this shortening, says Einstein, the moving observer will be unconscious, for not only is the circle flattened in the direction of motion, but the platform itself and all it carries (including the observer) share in this shortening. Even the observer's measuring rod is not exempt. Laid along the diameter of the circle which is perpendicular to the line of motion it would indicate, say, ten centimetres; placed along the shortened diameter, the rod, being itself now shortened in the same ration, would apparently indicate the same length as before, (ten centimetres) and the moving observer would have no suspicion of what we might be seeing. in fact, he might with equal right suppose himself stationary and lay all the motion to the account of our platform. And if we had a circle painted on our floor it would appear flattened to him, though not to us.

Again, the clock on the observer's platform would exhibit to us, though not to him, an equally eccentric behaviour. Suppose that other platform stooped long enough for a comparison (synchronisation) of clocks, and then backing off to get a start, flashed by us at high speed. As it passed we would see that the other clock was apparently slow as compared with ours, but of this the moving observer would be unconscious.

But could he not observe our clock?

Certainly, just as easily as we could see his.

And would he not see that our clock was now faster than his? "No," says Einstein. "on the contrary, he would take it to be slower"


Here is a paradox indeed ! A's clock appears slow to B while at the same time B's clock appears slow to A ! Which is right?

To this question Einstein answers indifferently: "Either. It all depends on the point of view."

In asserting that the rate of the moving clock is altered by its motion Einstein has not in mind anything so materialistic as the motion interfering with the proper functioning of the pendulum or the balance wheel. it is something deeper and more abtruse than that. He means that the flow of time itself is changed by the motion of the system, and that the clock is but fulfilling its natural function in keeping pace with the altered rate of time.

Back Sunday-Monday

cool bananas ... greg