Lorentz Invariance as a Dynamic Symmetry

If all the forces o f nature can be reduced to those which follow from a linear combination o f a scalar and vector potential, as in electrodynamics, Lorentz invariance can be derived as a dynamic symmetry. All that has to be done is to assume that there is an all pervading substratum or ether, transmitting those forces through space, and that all physical bodies actually observed are held together by those forces. Under this assumption bodies in absolute m otion through the substratum suffer a true contraction equal to the Lorentz contraction, and as a result o f this contraction clocks in absolute motion go slower by the same amount. The velocity o f light appears then to be equal in all inertial reference systems, if Einstein’s clock synchronization convention by reflected light signals is used and which presupposes this result. The Lorentz contraction and time dilation measured on an object at rest relative to an observer who gained a velocity by an accelerated motion is there explained as an illusion caused by a true Lorentz contraction and time dilation o f the observer. Both the special relativistic kinematic interpretation and this alternative dynamic interpretation give identical results only in the adiabatic limit where the accelerations are small, because if the Lorentz con­ traction is a real physical effect, it must take a finite time. However, to break the peculiar interaction sym­ metry with the ether, and which in the dynamic interpretation is the cause for the Lorentz invariance, the accelerated m otions must involve rotation. Only then can non-adiabatic relativity-violating effects be ob­ served and which would establish a preferred reference system at rest with the ether. Under most cir­ cumstances relativity-violating effects resulting from such a dynamic interpretation o f special relativity would be very small and difficult to observe, a likely reason why they have evaded their detection in the past. For the rotating earth a residual sideral tide has been observed with a superconducting gravimeter, and which could be explained by an “ether wind” o f about 300 km/sec at rest with the cosmic microwave background radiation. However, because o f the observational uncertainties in measuring the terrestrial tides no definite conclusion can be drawn. A number o f new experiments are therefore needed to decide the question regarding a possible weak violation o f special relativity.