How to test length contraction by experiment?

We could if you would use my numbers instead of yours. The reason is that my numbers do not end up with the far end of the ruler moving in the opposite direction that the ruler itself is moving.

But when we use your numbers, we end up with the far end of the ruler moving in the opposite direction that the ruler itself is moving, and that result is problematic. If you get a result like that, then you need to consider which of the overlooked details are critical to getting the correct solution. That is why I mentioned the bug-rivet paradox. It seems like a paradox until one realizes that the material consideration is important to solving it properly. Same with your scenario here.

Well, you're really not doing a Lorentz transform, because you are starting with the ruler at rest, and then accelerating it in a way that you have chosen specifically. I gave you alternative numbers which you could use which avoid the problematic outcome, but you don't want to use those numbers. Neither of our numbers came from any actual Lorentz transformation, we just chose them.

Are you applying a force to the far end to push it to the left? If not, then there is no reason for it to move to the left.

You are not considering where any force is being applied, and you are not considering that the information regarding that force can only propagate through the ruler at finite speed.

Try this, imagine the ruler is being pulled by the front. So using your method, at t=1 the front end is at x=11. Now, assuming the information regarding the force propagates instantaneously to the rear, then you might assume that the rear is located at x=11-8=3. But, if the information regarding the pulling force has not even reached the rear at t=1, then the rear should still be located at x=0. Now do you see the problem with ignoring the material considerations?

See above.

See above.

 

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This.

 

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When we do not agree on a outcome of a theory while we all correctly use the theory, then the theory has zone of doubt. A perfect theory does not make people disagree. For example , Newton's gravitational theory. When the speed and the radius of an orbit are determined, everyone gets the same result.

But the Lorentz transform make people to disagree. When you say that I'm wrong, you have to find arguments outside the theory such as speed of signal or have to change the original condition to make the outcome acceptable. Finding arguments outside the theory is like to argue against a square orbit by saying that you have not taken into account electrical force which is outside Newton's gravitational theory. With Newton's theory, we do not have to go outside the theory to point out if someone is wrong. If the orbit is not a cylindrical curve, it is wrong, that's all.

You do not say where is the error with my case because inside the Lorentz transform there is not argument against my application of it. If a correct application of a theory gives a problematic result and we have to search for argument from the outside, then the theory must have hole.

 

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You have not correctly applied the math.

No theory is perfect. They are working models.

This isn't a "disagreement", you have implemented it wrong.

Not true, actually. Newton's gravity is a very good approximation, but it is an approximation.

You might want to read up on the precession of Mercury. Einsteinian GR gets it right; Newtonian gravity does not.

No. The onus is not on us to teach you how to use it correctly.

No. You are applying it incorrectly.

 

This is what i'm interested in. Please show me.

 

Not necessarily...particularly one as thoroughly tested as SR.
One point that I don't believe has yet been raised is the connection and interchangeability of time dilation and length contraction. If you have one, you must by necessity have the other.
In fact I would say that this must hold [length contraction and time dilation] if the constant invariable nature of "c" is to be maintained.

 

That's only correct in SR if you are not translating from points on the circumference of a relativistically rolling wheel onto ground frame coordinants. The emission point is located at the end of a length contracted spoke and the emitted photon travels in a straight line from that point to the camera at c.

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http://www.thephysicsforum.com/spec...elativistic-rolling-wheel-ii-3.html#post12639

 

"the connection and interchangeability of time dilation and length contraction. " is exactly what we are talking about in this discussion. I have shown in the article "From Michelson–Morley experiment to length contraction"
https://pengkuanonphysics.blogspot.com/2019/08/from-michelsonmorley-experiment-to.html
or https://www.academia.edu/40208137/From_Michelson-Morley_experiment_to_length_contraction
that time dilation is sufficient to derive SR and length contraction is superfluous.

 

Superfluous??? so not wrong.
OK, it is probably beyond my pay grade to argue any further re the technicalities, but I would say to you that if you are as confident as you appear to be, why not write up a professional scientific paper for peer review? Afterall as I have said many times, forums such as this, open to any Tom, Dick or Harry, is not really conclusive re your results, particularly when others that are capable on this forum, have shown your claim as invalid.

 

I mean that length contraction is derived theoretically, so it is not necessary as an assumption before deriving SR. In fact length contraction has never been tested directly, only indirectly such as muons experiment.

It is because "others that are capable on this forum, have shown your claim as invalid" that I cannot get my paper through the peer viewer.

 

Perhaps you need to seriously consider what they are telling you, and modify your paper accordingly?

Further personal observations that may be relevant...
Both length contraction and time dilation are only evident from the observers point of view of any object moving with relation to that observer....

 

Or does this suffice to illustrate length contraction....
https://en.wikipedia.org/wiki/Bell's_spaceship_paradox

 

By discussing with them, I see how most people think and I try to accommodate my explanation. But the idea that SR has problem blocks people 's thought and they do not continue to read my explanation which does not contain error. Like in post 105 where I ask DaveC426913 to show me where I have done wrong. He give nt answer. I think he does not find any.

Time dilation has been directly tested, but not length contraction. I have derived length contraction from time dilation which shows that the assumption by Lorentz is not necessary to explain Michelson-Morley Experiment.

Precisely, I have used Bell's_spaceship_paradox to propose a test which will show the existence or not of length contraction.

 

He does need some sleep...give him time.

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As I said previously, I'm not really able to discuss too deeply, but I also see the interchangebility of length contraction and time dilation, as implying both are correct.
Irrespective of the opinions though here, I would still submit a paper for more professional views. Personally, it's a nice change to see someone as polite and apparently decent as yourself, putting an alternative view without the arrogance, pomposity, and delusions of grandeur...congrats.

 

Thank you. There is a long long way to go before people accept just to consider the possibility that SR is flawed. I have been bumping into the wall for so long already. Arrogance will only make things worse.

 

Kuan Peng;

[The purpose of the M-M experiment was to detect a difference in the transit times of the light signals along two orthogonal equal length paths. Calculations based on the 30 meter/sec speed of the earth, predicted the signal in the direction of motion x, would lag behind the signal at 90 deg to x. With a 360 deg rotation of the setup, the maximum time would change from one direction to the other. There was no difference detected]

[The quoted portion from your paper is in error. The interferometer was set up on a stone slab in a fixed position within the lab, and only allowed a slow rotation of 360 deg/min. The question was: does the earth's motion affect the transit times?]

[In the graphic, the left figure shows an overlay of the light (orange) transit times for the x direction and the p(erpendicular) direction. The speed is exaggerated to emphasize the differences. The times are those perceived by an observer who is not moving relative to the sun, i.e. in a fixed location along the earth orbit, watching it pass. The reflection events Rx and Rp, show the x signal one order of gamma later than the p signal. The question is: how to remove that difference. About 1889 O. Heaviside derived an expression for the deformation of em fields. This idea via G. Fitzgerald, apparently reassured Lorentz, who had already considered it, to include it in his transformation equations bearing his name.

The middle figure shows how one order of gamma length contraction results in simultaneous return times for x and p. Comparing the p axis to a light clock with transverse oscillation, it also shows time dilation for p. It also explains why c* p-transit time = gamma, compensates for length contraction of x. The observer in the lab is also affected by time dilation, and considers 2gamma as the standard or 2 as shown in the right figure. The final results, the physics of the experiment happen as if the lab was not moving, in agreement with SR.

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In reading it, the earth speed should be 30 km, but the results don't change.

 

Thanks for reading my paper and writing a comment.

First, there is confusion about what is the lab's reference. I think that your lab's reference is the interferometer's. My lab's reference is the reference of the sun. So, interferometer's reference is moving and the lab's reference is immobile. Sorry for not having explained this in my paper.

Then, I do not see your point. It seems to me that you are arguing that length contraction is useful to explain the Michelson-Morley experiment. I agree with that because I have derived the length contraction formula using time dilation. My point is that we no longer need to suppose that length should contract and derive the formula from the experiment. Length contraction is a consequence of time dilation, not an independent phenomenon.

I saw it.

 

The observers are in the lab on the earth, so it’s their observations that are in question. For an inertial frame both td and lc occur, and it’s the complementary nature of these effects that preserves constant light speed.

I suggest you do more research.
A good source for copies of the MMX papers is aip.org.

The ‘twin paradox graphical solution’ is a misinterpretation, with some errors.
I crossed paths with B. Jordan at SCF 12 yrs ago, but was not aware he had a book.
You can’t believe everything from the internet.

 

Length contraction, time dilation, and relativity of simultaneity are all related. None are independent of the other.

Einstein derived all three from one premise, namely that the laws of physics (including the constancy of the speed of light) are the same in all inertial reference frames.

Perhaps you are studying how Lorentz himself might have derived these things, I don't know. But Einstein is the one who derived the three concepts properly, and that is why he is credited for relativity theory, even though the equations of SR are named after Lorentz because he derived them first by other means.