Abstract

The pulse rates of some millisecond pulsars have long term stabilities that rival our best atomic clocks.  Furthermore, the pulsars are not affected by the dynamics of our solar system, which produce cyclic variations in earth based atomic time standards.  Measuring time in "pulsar seconds" and Einstein's "time" in uncorrected atomic seconds leads to two different measures of the speed of light, both of which have important physical interpretations that are discussed.  The evidence indicates that Einstein's definition of "time" and his principle of relativity are very useful but not universal "truths" and that Newton's ideas of time and space were discarded prmaturely.