steve@sri-unix (07/29/82)
One time I went down to one of our local universities and dug up a PH.D candidate in physics and asked him, in a much more complex fashion, the question asked by whuxlb!ech (that is, what is the propagation delay of gravity). The answer was also complicated, but it went something like this: The question you ask is meaningless. How can body A measure his response to what body B is doing? For any given observed behavior at body A there are an infinite number of places in the universe that body B could be that could cause the effects. Yes (I responded), but we are not dealing with an infinite number of places, but rather the end points of a well defined line. When body B goes from one place to another, then what is the precise observed effect at body A when B reaches its end point? How much longer does the change in effect occur at A when B reaches his end point? (he responded) Now you are falling into another trap. There is no such thing as "simultaneity" in a relativistic universe. To ask any question about "the same time at two different places" is meaningless. And so on... This was all with respect to the General theory of relativity, which has apparently fallen into ill-repute in recent years (due to its conflicts with quantum theory). Around and around I went with him, and every question I asked came down to "That is meaningless - the effects you are looking for either do not exist or cannot be measured." Sigh..... Steve Den Beste Tektronix