The luminuferous aether was supposed to be the reference frame that would be at absolute rest. The Michelson-Morley experiment was designed to test the earth's relative velocity to the aether by measuring two beams of light going at right angles, and for six months. If the earth is moving from left-to-right, right now, in six monthts, it will be moving in the opposite direction, from right-to-left -- this is inevitable as the earth is moving in a nearly circular path around the sun. So wrt the aether, the earth would be absolutely moving in one direction right now, and absolutely moving in the opposite direction six months from now -- always wrt the aether. Since light is also made up of waves, the wave would interfere constructively and destructively, as all waves do, but since the earth will change direction, from left-to-right to right-to-left, the intereference pattern would shift. The null result (no shift) was subsequently interpreted that there is no such thing as a frame of reference at absolute rest. So the concept of an aether was eventually abandoned. And in 1905, Einstein published his papers, which became known as the Special Theory of Relativity. In this theory, time can slow down, and space can contract, depending on the relative velocity of two observers. And so the Newtonian concept of absolute time and absolute space has become a thing of the past.
WLC has gone to great strides to deny SR, simply because in the Kalam argument, he wants to absolutely (pun intended, :-D ) hold on to the idea that the universe had a beginning. In such a scheme, this t =0 would be absolute.
