Re: A senior moment... But would like to hear views
MRHall,
Einstein postulates that it may be possible to travel to the past, but only after we have reached speeds faster than the speed of light (which HE said we can't reach).
It's a lot more than "he said - she said" when it comes to luminal or super luminal velocity for objects that have a rest mass. The entirety of
experimental physics since about 1865, not 1905 when Einstein wrote his paper on Special Relativity, suggests that traveling at or above the speed of light is not possible (for particles that have a rest mass). Einstein did not invent that idea. He quantified, extended and fully explained the problems encountered by Lorentz and Maxwell - problems discovered at about the time of the American Civil War. Advanced physics was not suddenly "invented" by Einstein in 1905. Advanced physics is an on-going process and the ideas that we deal with today in physics came to light in the 19th Century.
Please note that I made reference to
experimental physics rather than "someone postulated this or that idea". To date there has never been even one experiment that has negated either Special or General Relativity...none. What Einstein postulated is much, much more than a situation of "one man's opinion". It is a fact that is supported by over a century of experimental verification.
Are SR/GR the Final Answer? No. They aren't. General Relativity predicts the limit of its own downfall...Einstein proved in his theory that it was not the final answer and showed us where it breaks down. We know that, we have always known that, and Einstein knew that to be the truth. ALL physical theories are approximations of reality. But what we do know and accept is that we see what we see and determine what we determine from theories that are backed by experiment and general observation of the world around us. There will, eventually, be a new theory. That theory will have constraints and limits. Whatever theory it is that replaces SR/GR will be such that it will
absolutely include Galilean, Newtonian and Einsteinian physics as limiting situations. Why? Because when we look out into the world around us we see how it works. We've run experiments. We've posed theories. We've tested the theories against out observations and they are valid...to a limit. Any new theory that does not verify what we already know, at least as a limiting situation, will not be correct.
We already know as a matter of verified fact that objects that have a rest mass - normal matter rather than photon-like objects - are without exception subject to the effects of Special Relativity. If you accelerate them their mass increases much faster than the increase in velocity. Their mass becomes infinite at the speed of light and we do not have infinite energy available with which to accelerate them to the speed of light.
