Experiment to demonstrate mutual observed time dilation

Pete, 2inq,

Huh?!?!?

Try this:

1) R will receive a positive count from C1, indicating that C1's 1.3GHz counter has accumulated more ticks than C1's 1.3GHz receiver
2) R will receive a positive count from C2, indicating that C2's 1GHz counter has accumulated more ticks than C2's 1GHz receiver.

Interpretation:
C2 says that C1's clock is running slow
C1 says that C2's clock is running slow

What in hell are you guys talking about? There is no such thing as "one way" time dilation according to SRT (for objects with relative velocity. This is not abour GR either.). The relative velocity between C1 and C2 is pure and simple. C1 will see C2 dilated and C2 will see C1 dialted. If you think this isn't true, please provide a physical diagram and a few equations to support you statements.

 

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I feel like we are seriously regressing here. SRT says only one thing regarding time dilation. That an observer will see a clock moving wrt him as dilated, by gamma, as a function of the velocity between them.

SRT then says one other thing in general - There are no preferred reference frames.

Therefore, two observers, from their rest frames, will always see the other guy as dilated (slow). I appreciate everyones input, but please people, let's focus a little.

And Mac, why are we debating anything non-SRT in this thread? This experiment is to test the idea. We all know your position, and this experiment is largly inspired by you. We don't need to be reminded that mutual dilation is a problem for you. We get it.

 

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This is correct. I'm getting really confused by you gents...

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:m:

 

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Geist,

Yes, all of the things you mention must be considered. I will also need some supports at right angles to the radius arm to prevent torsional problems. Certainly thorough spin testing and balancing will be done prior to any actual runs. Remember that we are talking about 15 RPMs here, with a rim speed of about 350 MPH, and 25g's of acceleration at the rim. A 1lb electronics module will weigh 25lbs at speed.

Preliminary estimates for the motor indicate a torque requirement of less than 20lbs(wind load at 350 MPH with aerodynamic shell plus support arm) x 300ft (radius) <= 6000 ft-lbs. This may be a gasoline engine, geared WAY down.

 

superluminal, what I am thinking of is something I read about rotating rigid discs. I would guess Pete is speaking about the same thing, but I'm not positive. I believe
Max Born had something to do with it. Just as the clock postulate seems in violation
of General Relativity, rigid bodies seem in violation of SRT, but all kinds of exceptions
are made to both theories. There is a continuous range of time dilation effects extending out from the center of a rotating body. Here is a short cut from Stanford:

"What happens to rotating solid objects in relativity theory?
In special relativity, there are actually no solid bodies. On a rotating disk on a fast enough record player, the center is stationary, but because points on the circumference are moving, their proper time is different that what is measured at the center of the disk. Between the center and the edge, there is a continuous range of special relativistic time and space distortions being generated from the perspective of someone sitting at the stationary center of the disk. This is known as the Ehrenfest Paradox. There will be no disagreement on the length of the radius of the disk by anyone, however, for any segment on the circumference, they will see less than 2 x pi x R for the circumference. Despite the fact that to us the disk appears solid and rigid, as an OBSERVABLE object subject to special relativity, it is an almost plastic object capable of being deformed as judged by the images it presents us which are formed by the propagation of light.

In special relativity, there are no rigid bodies as well, because such a body is defined by the distance between each atom being fixed and not changeable. When one part of the body comes to a stop, every atom also comes to an instantaneous stop at the same instant. In relativity, there is no way in which the information can travel faster than light, so that there is no way that a 'rigid body' can come to an instantaneous stop."
http://einstein.stanford.edu/content/relativity/q1973.html

 

MacM should remember his older thread about the Merry-go-round, hehe. The radius
was not effected by Lorentz contractions, but the CIRCUMFERENCE of the merry-go-round WAS shortened. Some more of that, uh, unintuitive relativity. Something like
that, but I have to go out of town and don't have time to look it up.

 

Hafele and Keating Experiment:
"During October, 1971, four cesium atomic beam clocks were flown on regularly scheduled commercial jet flights around the world twice, once eastward and once westward, to test Einstein's theory of relativity with macroscopic clocks. From the actual flight paths of each trip, the theory predicted that the flying clocks, compared with reference clocks at the U.S. Naval Observatory, should have lost 40+/-23 nanoseconds during the eastward trip and should have gained 275+/-21 nanoseconds during the westward trip ... Relative to the atomic time scale of the U.S. Naval Observatory, the flying clocks lost 59+/-10 nanoseconds during the eastward trip and gained 273+/-7 nanosecond during the westward trip, where the errors are the corresponding standard deviations."

Eastward Journey, Westward Journey (Gamma time dilation)
-40 +/- 23 ns , + 275 +/- 21 ns (Predicted)
-59 +/- 10 ns , + 273 +/- 07 ns (Measured)
(J.C. Hafele and R. E. Keating, Science 177, 166, 1972)


It has been a great while since I actually considered SR or GR theory, as was evident from my last couple posts. I have just accepted them as theory-fact for so long and then never gave another thought to the whole of it. But while gamma may be a real observable phenomenon, it is the validity of interpretation that is the issue. Is it not [maybe]?

Since things like: exact, solid, etc are human inventions [abstractions] and are not really real. These mythical words only indicate the accuracy & predictability of nature’s differing topologies as seen through human eyes. As 2inquisitive pointed-out - what does “rigid” mean in terms of relativity? When considering energy [reality] we can conceive of that being: vibrating strings, waves, or energy in motion. So, reality seems more fluid rather than rigid. And if the energy that makes-up the clock is deformed within a field [gravity] and the clock [fluid-like energy] is deformed by movement in the direction of its movement [kinetic] and even then it is moving through other fields of energy [gravity, magnetic]; then what was demonstrated? That the clock's [which is made of fluid-like energy] unreliability increases the more phenomenal stress that it is subject too? I am not sure what the proper interpretation of gamma is? Did you demonstrate micro-amounts of time dilation or micro-amounts of clock deformation(s) which made the clock unreliable?

 

2inq,

So it dosen't sound, from the description of the rotatig disk you posted, like there is any conflict with what we are trying to do here. It makes sense that the center of the disk would observe a continuum of dilation along the radius. And from any point along the radius, the center would be equally dilated.

itopal,

The proper interpretation of gamma, according to SRT, is that objects that move relative to one another observe each other to be dilated by virtue of their relative velocity. As for clock deformation, that will occurr. Crystal oscillators distort under increased g forces. Our setup will experience approx. 25g's at the rim. It is the job of the experimenter to properly characterize and calibrate the oscillators such that this effect is nulled out.

 

super,
In the post which you quoted, my conclusions were mistaken.

See [post=800354]post 800354[/post] for the corrected analysis.

Note that C1 doesn't actually have a single SR-compatible (inertial) rest frame; C1 is continuously changing frames. C1's actual rest frame is non-inertial, which can only be analysed with GR.

The situation can be analysed with either SR or GR, both give the same result - GR says that in C1's frame, C2 is higher in a pseudo-gravitational field and therefore runs faster. SR says that there is never any failure of simultaneity between C2's frame and C1's instantaneous frame for events occurring at C1 and C2.

 

Well Pete, I disagree. Position has very little to do with it. C1 and C2 have a relative velocity difference, right?

 

Yes, how about fiberoptic cables in lieu of coax.

 

Fiber optic transceivers would work fine. I even have some HP modules in a box somewhere.

 

Pete,

http://math.ucr.edu/home/baez/physics/Relativity/SR/clock.html

 

Sure. But C1 also has a relative velocity difference to when it was on the other side of the circle, yes? And C1's frame is not inertial, right?

Or, think of it like this.
Would it make any theoretical difference if C2 were not in the centre of the circle? SRT says no - all clocks in C2's frame will see C1 in the same way.

So, let's place C2 on the edge of C1's circle. Now C1 is effectively the 'travelling' twin in the twin paradox.

The twins in the twin paradox always have the same relative velocity difference, right? So why is one twin actually older than the other when the 'travelling' twin returns?

Did you read that article? What do you understand it to say?

 

Pete,

I understand it to say just what it says re acceleration and gamma:

C1's speed of movement is constant: 157m/s. C2, if at the center, is 0m/s for a relative difference of 157m/s.

No. If you mean it's speed of movement, clearly no. Which is all the 'v' in gamma is - speed. Not a vector quantity dependent on direction.

Nope. They are now comoving and in the same frame.

 

Hi super,

In the article context, this is discussing the timing of an accelerating clock in an inertial clock's frame. It does not relate to the timing of the inertial clock in the accelerating clock's frame.

There's a side issue here... C2 doesn't have to be at the centre to have speed of 0m/s. If you were watching from the sideline, you'd also have a speed of 0m/s in C2's frame, right?

No, no! Don't make C2 move with C1, just place C2 stationary on the edge of C1's travel circle so that C1 returns to C2 once each cycle. In that case, this is a twin paradox scenario. On each cycle, a little less time passes for C1 than for C2 - according to both clocks.

 

Pete, you have essentially described the ECI (Earth-centered-inertial) frame of GPS
where the clock synchronization takes place. Although some here only refer to the
'clock at the center of the Earth', that same clock (C2 in your example) runs in synchronization with a
clock outside the satellites orbit ( C1 corresponds to a GPS satellite clock) referred to
as a 'clock at infinity' in GPS papers. Clock C1 (satellite) always beats slower than
clock C2 (Earth-centered/your example centered) from either the center of Earth or
from a distant observer's frame of reference. Moving clock C2 up the arm of the centrifuge slightly corresponds to moving the GPS ECI clock up to the surface of the Earth. By pre-adjusting the frequency rate of clock C1 (satellite), C1 can be made to
keep synchroneous time with clock C2 (proved in GPS). Now, Pete, do you believe in
superluminal's experiment, clock C2 (unsynchronized with C1) will record C1 as beating
slower? I would think of course. Superluminal thinks clock C1 will also record clock C2
as beating slower than itself (C1), due to the 'reciprocity' issue in Special Relativity.
I do not think so, neither does MacM and others. Pete, do you think Special Relativity
predicts C2 will beat slower than C1 also? If not, superluminal will be wasting his money in
the experiment. Perhaps James R could also weigh in on this and give his opinion of
what SRT predicts. I admire superluminal's willingness to test SRT, but if the proposed
test has no chance of accomplishing anything, it would be a waste of superluminal's
time and money. Could you comment please, James R?

 

Sorry 2inq, I'm not inclined to follow the GPS discussion that's been happening.

On a side note, posts are difficult to read when you use arbitrary line breaks. How about putting your thoughts in meaningful paragraphs?

 

Sorry Pete, I had to make a correction. The essential question is: Does The Special
Theory of Relativity actually PREDICT each clock will record the other in the proposed
test as running slower than itself? If SRT does not predict that, then superluminal
would waste his money doing the experiment. That is why I asked if James R and other
experts in relativity theory would give their opinions.

 

In this experiment, SRT predicts that C1 will run slow in C2's frame, and C2 will run fast in C1's frame. At least, that's the results of my analysis of the situation with SRT. Superluminal disagrees, and we're currently engaged in dialogue to establish the facts.

If you would like James to comment, it would probably be more productive to send him a private message rather than hide your request at the end of a dense paragraph in a thread he isn't actively participating in.