MacM:
I'll start by answering your questions.
Given "A" & "B" clocks are both at an inertial relative rest in the same general location and synchronized.
If "A" is launched away from rest and accelerates to a velocity 0.8c from "B" what is it's tick rate compared to "B"?
I assume you mean after the acceleration period, once the final speed is reached. Answer: It depends on which frame you're observing the tick rate in. The Lorentz factor for this speed is 1.666. In A's frame, A's clock runs at the normal rate and B's runs slower by a factor of 1.666. In B's frame, A's clock runs slower than B's by a factor of 1.666 and B's clock runs at the normal rate.
By the way, this scenario is indistinguishable from one in which A and B are originally at rest and B accelerates away, leaving A at rest, except that the direction of motion of B would be the opposite to your original scenario.
That is, once the acceleration is over, there's no experiment you can do to show that the acceleration ever happened. Examining current clock rates won't tell you anything about the acceleration history of A or B. Do you agree?
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Now, comments on your reply:
MacM said:
What is useless is a theory that declines to be honest and acknowledge that it is actually based on a physical change in velocity (an absolute function) and not on relative velocity between clocks.
You're not talking about special relativity here, are you?
Because you DO know that special relativity ONLY considers relative velocities. There are no absolute velocities in the theory of relativity.
So, what theory are you thinking of, then?
Please re-read your post. You have "A" ticking slower than "C" in the "C" frame which would be correct.
But you then have "A" ticking faster than "C" in the "A" frame, which is false.
Ah, sorry. I was obviously letting true physics slip into my thinking, instead of going with what your fantasy physics says. My mistake.
Therein lies your problem. You fail to see why a clock running slower physically will be running physically slower in every frame. How it might "Appear" to tick from some other frame is not the issue.
Only the physical reality is the issue and the physical treality is that physical permanent time dilation is NOT a matter of observer perspective but a matter of actual motion induced by undergoing F = ma acceleration..
Ok. We're getting to the crux of this. Your statement in bold is very clear. Let me give you one more scenario, just so I understand your position.
You observe three clocks: A, B and C. At the time you observe them, you happen to be at rest relative to clock C. Note: I am not telling you that you are on Earth. For example, Clock C may be the clock you're carrying along with you in a spaceship travelling at unspecified speed v relative to Earth, for example.
So, you're at rest relative to C. From your reference frame, you measure the speeds of clocks A and B, which happen to be moving relative to C (you). You observe that clock A is travelling at 0.6c away from you. You observe that clock B is travelling at 0.6c away from you, but in the opposite direction to clock A. You have no information about how the three clocks might have accelerated (or not) before your observations.
Questions:
* Is it possible for you (C) to measure the tick rates of clocks A and B from your frame C?
* If so, what are the tick rates of clocks A and B?
* Are A and B synchronised? i.e. do they tick at the same rate?
* If you can, please specify how you might measure the tick rates of clocks A and B (assuming that such a thing is possible at all).
MacM said:
James R said:
Loaded question? It's a perfectly straightforward question. If you watch me drive my car, and my speedometer says I'm going at 50 mph, then will your radar gun also say I'm doing 50 mph, or will it sometimes give a different speed reading? That's all I'm asking.
You don't seem to get it. If you are going 50 Mph and I'm parked along side the road then my radar will say 50 Mph. But if you are traveling 50 Mph and try to compute my relative velocity to you bby v = ds/dt (by my clock) you would not get 50 Mph (although at these speeds the difference would be immeasurable).
I get what you're saying. You're saying that my speedometer, which does just such a computation of my car's speed, will NOT read 50 mph if your radar gun reads 50 mph. The difference might be very small, but it would be a real difference, according to you. Right?
Can you tell me what maths I'd have to build into my speedometer so that it would always read the same speed as your radar gun's measurement of the car's speed?
Or, are you saying that if I have my own radar gun in my car and I point it at you it will read your speed as something other than 50 mph?
Assuming you and your radar gun are at rest then from the measuring device you have the motion but in any absolute terms one doesn't know that until they compare the accumulated time on respective clocks.
So, speedometers are impossible?
I may be driving west at 50 Mph such that I am effectively moving east at 950 Mph while you apparently standing still are actually moving east at 1,000 Mph.
So, you stand still and your radar gun measures my speed at 50 Mph west. Let's assume, like in your example, that you are moving east at 1000 mph and my car is driving east at 950 mph.
Questions:
* Have I got it right that your radar gun would measure my speed at 50 mph west?
* What would the speedometer on my car say in this case?
* What would the radar gun in my car read when I point it at you?
* Is there any way I could tell from the measurements (radar guns and speedmeter) our actual speeds (1000 and 950 mph)? Bear in mind that the road may also be moving relative to something like the Sun.
* Actually, just to be clear, what are these 1000 and 950 mph speeds relative to? The road? A fixed point at the centre of the Earth? The Sun? Or what?
And your problem is a problem in SR not merely mine. You apply =/- signs to your math indicating which vector ov motion the clock has and that determines if the clock is speeding up or slowing down BUT that math does not answer why you do that since unless you knew the clock was returning to some other initial rest frame then you would predict it is slowing down.
I'm not entirely sure what you're saying here.
Your math has the same clock both slowing down or speeding up while leaving an initial rest position depending on which vector sign you apply.
My math has the clock speeding up or slowing down depending on the reference frame it is observed from.
Another example: I am driving along the road at 50 mph, east. You are driving your car next to mine, also at 50 mph east. Now, you slam on the brakes. What does your car do, in my reference frame? Answer: You started at rest in my reference frame, and when you slammed on the brakes you accelerated with increasing speed to the west. Agree?
Question: did you speed up or slow down when you hit the brakes? Answer: it depends on the reference frame we're looking at you from. From my car's frame, you sped up. From the point of view of a bystander on the road side, you slowed down.
Do you agree?
What I am asking you is whether the special theory of relativity correctly predicts appearances of clock rates. Or, to put it another way, does relativity predict anything about clock rates correctly, or is it all wrong?
It seems it likely predicts the "Perception" correctly.
How does it manage to do that? Surely if the maths is all wrong, it can't possibly work to even predict perceptions correctly. Is it just lucky?
So, is the speed of light a universal speed limit, or isn't it?
I suggest it is not.
Why have we never observed any massive object moving faster than light, then?
I suggest it is more a limit of physical dimension linkage. That is Lorentz Contraction of mass in the direction of motion (not space) causes objects to cese to exist in your physical universe but they continue to exist but at a different energy level universe.
Why have we never seen any object disappear from our universe into a different energy level universe, or any object suddenly appear in our universe from the other universe?
MacM said:
JR said:
SR says that if B moves at 0.8c relative to A, and C moves at 0.6c relative to B, then the speed of C relative to A is not 1.4c, but still less than the speed of light.
Yep it sure does. It should since it was designed to do so. Just as Einstein wanted the universe to be static and generated math to show it was (until it was proven to be expanding), he also wanted v = c to be a limit so wrote math to make it so.
You think? *sigh*
I thought you would have learned after all these years that the entire theory of special relativity (for a start) is
derived from only TWO postulates. From these two simple postulates, we get time dilation, velocity addition, "reciprocity", length contraction, relativity of simultaneity, and all the other good stuff you can't bring yourself to believe.
What is certainly NOT true is that Einstein could just add
ad hoc mathematics to make things the way he wanted them. The velocity addition formula of special relativity is not an "extra" add-on to the theory. It is a direct and simply-derived consequence of the same two postulates. There's no choice in the maths once the two postulates have been specified. And they are exceedingly simple.
And in all these years you have never been able to bring yourself to directly say that either of the postulates of special relativity is flawed. Which means, of course, that all your attacks on the mathematics and your comments about "reality vs. perception" are useless, because if the postulates are right then the maths must be right. If it wasn't, somebody would have shown the errors some time in the last 100 years.
Similarly, the v=c speed limit is not something ADDED to the theory of relativity. It is a derived
consequence of those same two postulates.
I'm extremely disappointed that you do not know these things.
In short, what all this means is that to attack special relativity, you need to attack at least one of the two postulates - with reasons, of course. But you're not brave enough to do that, are you?
Do you disagree with this? Is a speed of 1.4c possible? (Yes or no)?
Yes and no. Not in your physical universe but at some absolute reference level yes. Such object would be at 0.4c in the higher level outside your universe.
So what you're saying is that the theory you wish to replace relativity with doesn't apply to our universe, but only to a different universe at a "higher level" - an unknown fantasyland MacM universe that we have no way of detecting.
Correct?