On Thu, Feb 20, 2014 at 10:06 AM, H Veeder <[email protected]> wrote:
As Dave has mentioned, Einstein's reason for postulating the constancy of c > was partly motivated by his examination of the laws of electrodynamics. > ... Here is the introduction to his paper ON THE ELECTRODYNAMICS OF MOVING > BODIES. > That's a remarkable paper to read. Einstein proposes two bold postulates -- (1) let the velocity of light be constant; (2) let physical laws apply to any bodies in the same manner, no matter what system of coordinates and uniform translation (as well as (3), let space be homogenous). The reader is not told why he should go along with the speed of light one, and you can imagine that people didn't want to suspend disbelief on that one at first. But then Einstein goes on to derive a bunch of remarkable mathematical results from these postulates that make sense of Maxwell's equations, the Doppler effect, the movement of an electron, and so on. You can also see E = mc^2 implied in the equation for the energy of the motion of an electron, towards the end. Occasionally there is a statement that might possibly be experimentally verified. I doubt this system appeared to Einstein as though by way of revelation, at least at first. Along the lines of what Harry suggests, I'm guessing that he was irritated by the different ways in which electric and magnetic fields were being calculated at the time, depending upon whether a system was at motion or at rest, and that this was the thread in the sweater that, when he pulled at, kept on unravelling, until at some point he found himself looking at a very different system from the one he at first anticipated. Eric
