Abstract

Relativity started with Galileo and his motion relative to the stars. Inertia came into the picture with Newton 's laws of motion, as did the notion of motion in the absence of forces. James Clark Maxwell gave the scientific community a lot to think and write about when he fashioned and published his electromagnetic equations in 1873. A community that was, by this time, used to explaining physical phenomena in mechanistic descriptions found it difficult to come to grips with the field type equations Maxwell gave them. This desire for a mechanistic description for the propagation of light gave birth to the notion of a mechanical medium, the ether, in which light might propagate. Experiments were no help in continuing the mechanistic view of the world, as they could find no ether. Measurements of the speed of light with respect to the supposed ether came up with a negative result. Einstein looked at this result very differently than did his peers and took this to mean that the speed of light was a universal constant, no matter how one attempted to measure it. This different viewpoint gave rise, ultimately, to Einstein presenting two theories to the scientific community with the word ?relativity' in their titles.

Now one hundred years after Einstein presented the first of his theories of relativity this article is offered, not to pay tribute only to these contributions of Poincar? and Einstein, but to mark the centenary of the discoveries of 1905 by presenting a critical reconsideration of the ether idea in modern physics, astronomy and cosmology.