07-22-09, 11:07 PM #421
You record two clocks moving at 0.8c (with respect to you). One of them fires its rockets and comes to rest (with respect to you).
SR says that the tick rate of the clock that is still moving is dilated with respect to the clock that accelerated.
07-22-09, 11:10 PM #422
07-22-09, 11:45 PM #423
It is true that the physical tick rate of both clocks A & B is unchanged by the existence of some other clock moving in another inertial frame. I.e. a just made pregnant lady can expect nine months to pass by her clock before the baby is born.
However assuming I am not in her frame but another inertial frame moving wrt hers I can measure that it takes her longer to make the baby. This is because I will use my clock, not hers to determine the rate the fetus is growing just as I will use my clock to determine the speed that her house is moving away from me. In fact I am very stubborn about this - I always compute ALL rates the same way no matter what they are or where they are or how they are moving wrt to me and my clocks.
I determine a rate of x change as follows:
The value of x at some initial time t1 is noted and is x(t1). Then later x(t2) is recorded. Then the rate of x change is [x(t2) -x(t1)] / (t2-t1)
The pregnant lady would do exactly the same but use her clocks. For example her time interval is (T2 -T1) and her X1 is my x1 event. To take a specific example, For both of us X1 & x1 are touching a lighted match to a fire cracker fuse, and for both of us, X2 & x2, are the fire cracker exploding. There are two identical firecrackers, one stationary in each frame. (I light mine, she lights hers. We do not even attempt to do this simultaneously as that will just lead to arguments in this discussion.)
I might add that if we ever had what you call a "common rest frame" it was for both of us many years ago and neither she nor I were old enough to have any clocks or firecrackers back then.* In fact the clocks and fire crackers have never been at rest in the common rest frame as all were only made a few weeks ago. I.E. NEITHER the clocks nor the firecracker were ever accelerated so they cannot be affected by acceleration that was in the distant past, long before they even existed.
You will agree that at least (T2 -T1)' > (t2-t1) or (T2 -T1)' < (t2-t1) as you do not deny "one way" time dilation, but refuse to be both are true and that is correct as the prime I added to the right side quantities is to indicate that (T2 -T1)' is the time her fuse burns by my clocks and I cannot belief it both longer and shorter than the time (t2-t1), my identical fuse took to burn by my clock.
Exactly the same for her either: (T2 -T1) > (t2-t1)* or (T2 -T1) < (t2-t1)* but not both. Where an asterisk is added to time interval for my fuse to burn as measured by her clock.
SR states time is dilated in the frame moving wrt you. She and I both accept that. I.e. she believes (or measures) (T2 -T1) < (t2-t1)* and I believe (or measure) (T2 -T1)' > (t2-t1). Or in the less well defined words you use:
Both measure the others identical fuse as burning more slowly. You MacM assert that this is not physically possible. So you go on to conclude that since what SR asserts is nonsense, SR must be at least partially wrong.
I.e. you say it is not possible for her to measure my time interval (t2 -t1)* as longer than hers (T2 - T1); and also for me to measure her time interval (T2-T1)' is longer than mine (t2-t1). But it is as (t2 -t1)* IS NOT THE SAME AS (T2-T1)' Your lack of (actually your refusal to use) well defined symbols to aid clear thinking is at the heart of your belief that SRT is wrong, I think.
There is nothing impossible here; again:
(t2 -t1)* IS NOT THE SAME AS (T2-T1)'
It only seems to be the same when imprecisely expressed in your words as follows:
"Both CANNOT measure the others identical fuse as burning more slowly. THAT IS NONSENSE"
Probably all but you can see what the problem is: (Lack of precise terminology.)
Possibly even QQ can or else he believes that (t2 -t1)* IS THE SAME AS (T2-T1)' since he believes time dilation is an inertal effect and in this example no clock or firecracker was ever subjected to any acceleration. I would like to know what he thinks.
*Actually neither of use even existed back then (more than 150 years ago) when the acceleration took place - see post 425 for more details.
Last edited by Billy T; 07-23-09 at 12:20 AM.
07-22-09, 11:51 PM #424
so Uhm BillyT how did you get to be moving at relative V to the pregnant lady in the first place if not for acceleration?
also as far as the lady is concerned she would give a rats ar*s it's still a bloody long time [ and SRT will inevitably make it the pregnancy, longer for the father and not her...oh no!!]
Last edited by Quantum Quack; 07-23-09 at 12:12 AM.
07-23-09, 12:07 AM #425
It is the velocity difference (an energy state in my opinion) that causes dilation and the reality is that you only get changes in velocity by accelerating.
Indeed the correct total time dilation must also include a gamma integration of velocity during acceleration period because there also exist periods of differing velocity (Frames).
But they will dance all around this issue and refuse to acknowledge the linkage. James R will argue that relative veloicty is the cause and that reciprocity is physically real. Even though it is physically impossible and has never been tested and appear is untestable. There is absolutely NO emperical data to support such ludricrus concept ad mere relative velocity a a cause of physical change.
Just as you have relative velocity between different frames there exists the "Apparent" relative acceleration. That isas the train pulls out from the station the statin appears to be accelerating in the opposite direction.
There is however a very important distinction in the two observations.
People on the train are being subjected to F = ma and are undergoing v = at. The people at the station have no "F" and have no actual "V".
That is why their clocks do not physically dilate.
07-23-09, 12:11 AM #426It is the velocity difference (an energy state in my opinion) that causes dilation and the reality is that you only get changes in velocity by accelerating.
07-23-09, 12:11 AM #427
I still wish to know what you think. Which is it:
(t2 -t1)* IS NOT THE SAME AS (T2-T1)'
(t2 -t1)* IS THE SAME AS (T2-T1)'
There are only these two alternatives - chose one.
My bed time now - hope I can sleep, but not knowing until tomorrow which you will choose may make that tough.
07-23-09, 12:13 AM #428
07-23-09, 12:15 AM #429
SR (actually LR) properly considers acceleration or who has "Actual Velocity" and ignores relative velocity when predicting physical time dilation of particles in the lab. Relative velocity measurements without consideration of who accelerated or who remained at rest simply address appearances or illusions of motion and not physical change.
QQ is correct when he points out that there is simply no cause for physical change in a resting clock.
07-23-09, 12:19 AM #430
07-23-09, 12:22 AM #431
07-23-09, 12:22 AM #432
It is this later case that is at issue and not the "Apparent" dilation caused by relative velocity. When you stop the relative motion only one will be dilated relative to the other and it will be the most accelerated clock even though during relative velocity each "Sees" the other dilated.
Emperical data does not support the relative velocity view as being physically real.
I have shown in my radioactive decay clock scenario that it does not matter which frame you compare the clocks in after having had relative velocity the results remain the same only the clock with the greatest v * t is dilated and not vice-versa as a matter of frame perspective.
07-23-09, 12:26 AM #433
They want to argue about what SRT says or claims but not what common sense and emperical data suports.
07-23-09, 12:28 AM #434
07-23-09, 12:33 AM #435
So, do you think that Newtonian mechanics is a reasonable description of reality at non-relativistic speeds?
Do you think it is a problem that reality treats velocity as relative but not (the direction of) acceleration?
07-23-09, 12:35 AM #436
The problem with your statement Pete is you and SRT want to claim "Mere Relative Velocity " is a cause. As QQ has rightfully pointed out there has been no physical basis for a resting clock to physically change.
Further SR doesn't even compute that way they consider who accelerated by claiming "Switched Frames" or who has actual velocity in the relative velocity pair when predicting who is dilated which is more LR than SR.
It is interesting that they use Lorentz formulas and now Lorentz preferred frame view but still claim it is SR.
07-23-09, 12:42 AM #437
If you spot two clocks moving relative to each other and you, you have no way of predicting what there respective tick rates actually are based on your perspective of their relative velocity.
07-23-09, 12:47 AM #438
The velocity you will compute increases if your clock is ticking slower.
End of arguement. Anyother assertion requires that you ignore your prior stipulation that the accelerated clock is dilated.
07-23-09, 12:50 AM #439
Seems the pot calling the kettle black.
Your comments would carry more weight if you just provided a sound physics rebuttal and stopped trying reciting the very theory that is being challenged.
You could sttart by pointing out specifically how my car trip between two cities is not an accurate description of what is actually happening in SRT.
Keep in mind I could have Bob stationed at rest in city "B" and have him just look at the radar readings to conclude that Bill was driving 60 Mph all the way.
If so then you would agree that Bob predicts that Bll's watch would be running slow. So how is it then when Bob considers Bill's trip time he ignores the dilated clock he just predicted and computes distance changed because he accumulated less time.
He has to ignore his prediction that Bill's watch is dilated.
Last edited by MacM; 07-23-09 at 01:12 AM.
07-23-09, 12:53 AM #440
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