Jesse, Remember we are talking ONLY about PROPER TIMES, or actual ages. These DO NOT HAVE any MEANING IN OTHER FRAMES than that of the actual frame of the observer in question. So your comments that an observer's age will be measured differently in other frames, while obviously true, is NOT the observer's PROPER AGE or PROPER TIME. Every observer has one and only one proper age, that is his proper age to himself, NOT to anyone else, not in any other frame.
That holds for all your comments about age effects of acceleration being different in different frames. Of course they can be but that is NOT PROPER ACTUAL AGE. So I have to disregard all those comments because they don't apply to PROPER TIMES OR ACTUAL AGES. Proper time is ONLY one's reading of one's own clock, NOT one's own clock viewed from some other frame. Correct? Now a very basic question. Do you agree or disagree that all PROPER TIMES run at the same rate unless some effect causes them to run at different rates? Again this is NOT how clocks appear to run in any other frames but their OWN. If you do not agree then please explain why not and please PROVE to me that PROPER TIMES do not run at the same rate unless there is some actual effect that causes them to run at different rates. Edgar On Thursday, February 27, 2014 3:07:41 PM UTC-5, jessem wrote: > > > > On Thu, Feb 27, 2014 at 2:38 PM, Edgar L. Owen <[email protected]<javascript:> > > wrote: > > Jesse, > > First the answer to your question at the end of your post. > > Yes, of course I agree. Again that's just standard relativity theory. > However as you point out by CONVENTION it means "the observer's comoving > inertial frame" which is the way I was using it. > > > Thanks, it seemed like you might have been suggesting there was some > "natural" truth to calculations done in the comoving frame of two > obserervers at rest relative to each other, even though they could equally > well agree to calculate things from the perspective of a totally different > frame. > > > Now to your replies to my post beginning with your first paragraph. > > Certainly there are equations that do what you say they do, but I don't > see why what I say isn't correct based on that. Why do you claim it is > impossible to just take proper acceleration and calculate what my age would > have been if there was not any proper acceleration? > > > I don't claim it's impossible, just that it can only be done relative to a > particular frame. I can make statements like "I am now 30, but in frame A, > if I hadn't accelerated I would now be 20" and "I am now 30, but in frame > B, if I hadn't accelerated I would now be 25". > > > > An observer knows what his proper acceleration is, and he knows how much > various accelerations are slowing his proper time relative to what it would > be if those accelerations didn't happen. > > > "Slowing his proper time" only has meaning relative to a particular frame, > there is no frame-independent sense in which clocks slow down (or speed up) > due to acceleration in relativity. > > > > He has a frame independent measure of acceleration. He knows that > particular acceleration will slow his proper time by 1/2 so he can define > and calculate an 'inertial time' whose rate is 2x his proper rate. > > > Given the exact same proper acceleration, there may be one frame A where > at the end of the acceleration his clock has slowed by 1/2 (relative to the > time coordinate of that frame), and another frame B where it has slowed by > 1/3, and even another frame where it has *sped up* by a factor of 10. Do > you disagree? > > > > You seem to think it would be necessary to MEASURE THIS FROM SOME FRAME > for the concept to be true. It's not an observable measure, it's the > CALCULATION of a useful variable. Therefore there is NO requirement that > it's measurable in any frame because it's a frame independent concept, a > calculation rather than an observable. > > > Calculations are always calculations of the values of particular numerical > quantities, like the "rate" a clock is ticking. So, what matters is whether > the quantity in question is frame-dependent (like velocity, or rate of > clock ticking) or frame-independent (like proper time at a specific event > on someone's worldine), there is nothing inherent in the notion of > "calculations" that make them frame-independent. > > Also, *all* calculated quantities in relativity can also be > "observables"--it's straightforward to observe frame-independent quantities > like proper time (just look at the clock the observer carries), and > frame-dependent ones can also be "observed" if you have a physical grid of > rulers and coordinate clocks as I have described before (for example, to > find the "rate" a clock is ticking relative to a coordinate system, you > look at the time T1 it reads as it passes next to a coordinate clock that > reads t1, and the time T2 it reads as it passes next to another coordinate > clock that reads t2, and then you can just define the average rate over > that interval as [T2 - T1]/[t2 - t1], and if the difference between T2 and > T1 approaches 0 this approaches the *instantaneous* rate at T1). > > > > > Therefore I don't see any reason to accept your criticism in this > paragraph. If you disagree, which I'm sure you will, then explain why this > concept of inertial time is not frame independent and valid. Perhaps a > clear example would help? > > > > If you disagree with my statement above that different frames can disagre > ... -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
