A Disproof of the Principle and Theory of Relativity

[lidal]

Just now, joigus said:

There is no v in the problem you're setting up. No observer attached to the ship can measure any such v. 

Nobody, repeat, nobody stuck to the ship has any right to even start talking about such v. What v? What are you talking about?

What you are doing is using a quantity that only makes sense in the frame attached to a certain "rest observer" you're telling us nothing about in your calculations about another frame.

And yes, according to your main line of reasoning, space within a ship is non-isotropic, which is a ludicrous claim, of course.

 

 

Just now, swansont said:

You keep doing this - moving with respect to what? It’s a critical detail.

Answer: with respect to the source. If the source and observer aren’t moving with respect to each other, it doesn’t take more time.

The v in my equations is very subtle, but I just stated it to be the velocity of the ship relative to the sea, at least. v is actually absolute velocity, some 390 km/s,  but I did not want to refer to it as absolute velocity. In fact, if an actual experiment was done, the time difference between the two pulses is determined by absolute velocity of the ship, not by the velocity of the ship relative to the sea.

If you assume absolute reference frame, then there will be a change in the time light will take to reach the detector even if they are co-moving.

The reason I chose to base my argument on the velocity of the ship relative to the sea is that, we can agree on whether or not the ship is moving relative to the sea (we will not agree whether it is moving relative to the invisible, 'disproved' absolute frame). And we can somehow agree that light will take more time to catch up with a detector moving away from the point of emission (in the frame of the sea). If we agree on this, I can disprove the relativistic clock synchronization procedure.

 

 

 

Edited October 31, 2023 by lidal

[joigus]

2 minutes ago, lidal said:

The v in my equations is very subtle,

Not subtle, just wrong. It shouldn't be there.

Right now, what's the speed of your nose with respect to something I'm thinking of, but I'm not gonna tell you?

See?

That's your v.

12 minutes ago, lidal said:

If you assume absolute reference frame,

And this is a serious no, no. I hope you understand. If you don't, I can't help you, and I'd venture nobody else here can.

[swansont]

27 minutes ago, lidal said:

The v in my equations is very subtle, but I just stated it to be the velocity of the ship relative to the sea, at least. v is actually absolute velocity, some 390 km/s,  but I did not want to refer to it as absolute velocity. In fact, if an actual experiment was done, the time difference between the two pulses is determined by absolute velocity of the ship, not by the velocity of the ship relative to the sea.

But when we do Sagnac experiments, the result is consistent with the earth rotation speed, not some absolute velocity, which doesn’t exist in relativity.

We can look at interferometry results, and know that there is no effect from this alleged absolute velocity 

27 minutes ago, lidal said:

The reason I chose to base my argument on the velocity of the ship relative to the sea is that, we can agree on whether or not the ship is moving relative to the sea (we will not agree whether it is moving relative to the invisible, 'disproved' absolute frame). And we can somehow agree that light will take more time to catch up with a detector moving away from the point of emission (in the frame of the sea). If we agree on this, I can disprove the relativistic clock synchronization procedure.

We can agree that the notion of an absolute frame was disproved. And the fact that we can and do synchronize clocks means there’s nothing wrong with the mainstream understanding.

[pzkpfw]

99% of "issues" in relativity come down to the relativity of simultaneity.

That observers inside and outside the ship can agree the light pulses reach the detector at the same time, yet can disagree that S₁ and S₂ emit the pulses at the same time, is well understood.

There's no issue here except ignoring the relativity of simultaneity.

 

(Disclaimer: 99% of statistics are made up)

 

Oh! And then another cross reference: https://forum.cosmoquest.org/forum/the-proving-grounds/against-the-mainstream/3722813-a-disproof-of-the-principle-and-theory-of-relativity

 

[Halc]

9 hours ago, lidal said:

I didn't mention the frame because it was too obvious. Since we are talking about time difference as measured in the ship's frame, I meant simultaneous in the reference frame of the ship. 

OK, we're taking about the frame of the ship in all this. In that case, v = 0.  Or v = the speed of the water going by outside, but water moving nearby has zero effect on how long it takes for light to get between a bunch of stationary emitters and detectors.  Nothing is receding except the water, and the water isn't detecting any light.

[lidal]

13 hours ago, joigus said:

Not subtle, just wrong. It shouldn't be there.

Right now, what's the speed of your nose with respect to something I'm thinking of, but I'm not gonna tell you?

See?

That's your v.

And this is a serious no, no. I hope you understand. If you don't, I can't help you, and I'd venture nobody else here can.

Do we need to debate about the Silvertooth and the Marinov experiments again?  No, I don't necessarily need them this time. I have figured out a simple thought experiment that will make physicists scratch their heads. 

 

13 hours ago, swansont said:

But when we do Sagnac experiments, the result is consistent with the earth rotation speed, not some absolute velocity, which doesn’t exist in relativity.

We can look at interferometry results, and know that there is no effect from this alleged absolute velocity 

We can agree that the notion of an absolute frame was disproved. And the fact that we can and do synchronize clocks means there’s nothing wrong with the mainstream understanding.

You brought up a good point. Why absolute velocity doesn't show up in the Sagnac effect can be extremely subtle to understand. I have only this to say for now: the effect of absolute translational motion on the Sagnac effect is to delay each light beam equally, so no effect on fringe positions. (my new theory)

The same explanation for the Michelson-Morley experiment null result.

 

12 hours ago, pzkpfw said:

99% of "issues" in relativity come down to the relativity of simultaneity.

That observers inside and outside the ship can agree the light pulses reach the detector at the same time, yet can disagree that S₁ and S₂ emit the pulses at the same time, is well understood.

There's no issue here except ignoring the relativity of simultaneity.

 

(Disclaimer: 99% of statistics are made up)

 

Oh! And then another cross reference: https://forum.cosmoquest.org/forum/the-proving-grounds/against-the-mainstream/3722813-a-disproof-of-the-principle-and-theory-of-relativity

 

 

You don't seem to understand the whole point because you are busy searching the internet to find other sites where I have posted the same topic. 

I suspected and abandoned the relativistic approach from the beginning. I started with a classical approach and found a result that can divide physicists. Will the two pulses in the thought experiment arrive simultaneously or not? 

 

7 hours ago, Halc said:

OK, we're taking about the frame of the ship in all this. In that case, v = 0.  Or v = the speed of the water going by outside, but water moving nearby has zero effect on how long it takes for light to get between a bunch of stationary emitters and detectors.  Nothing is receding except the water, and the water isn't detecting any light.

No, v is absolute velocity. But my present argument is not like such and such experiment proves absolute motion. It is a simple thought experiment.

 

Again let us not forget where we started: the thought experiment. I hope to do the real experiment and get back to you one day.

Edited November 1, 2023 by lidal

[joigus]

4 hours ago, lidal said:

Do we need to debate about the Silvertooth and the Marinov experiments again?  No, I don't necessarily need them this time. I have figured out a simple thought experiment that will make physicists scratch their heads. 

I think you mistake me for somebody else.

But I see more clearly what you're doing here.

[lidal]

20 minutes ago, joigus said:

I think you mistake me for somebody else.

But I see more clearly what you're doing here.

Thank you for understanding. It is one thing to understand what I am saying and reject or accept it. It is another thing to (intentionally) not understand and twist it.

[Halc]

5 hours ago, lidal said:

No, v is absolute velocity.

If your proposal is one with absolute velocity, then it is a different proposal than SR. SR has relative velocity, not absolute. With SR, all calculations should be computed relative to the chosen frame, and you chose that of the lab in the ship. Under an absolute hypothesis, all calculations must be performed relative to the absolute frame, which has not been identified.

How do you know the absolute velocity of anything?  It's not like the water is stationary since water moves at very different velocities from place to place and from time to time.

Edited November 1, 2023 by Halc

[joigus]

24 minutes ago, lidal said:

Thank you for understanding. It is one thing to understand what I am saying and reject or accept it. It is another thing to (intentionally) not understand and twist it.

No, I mean, I see what you're doing here: The regular crackpot routine. See what happens when the voice in your head speaks louder than the world outside?

[Bufofrog]

6 hours ago, lidal said:

I started with a classical approach and found a result that can divide physicists. Will the two pulses in the thought experiment arrive simultaneously or not?

Are you saying that you think some physicists would think that the 2 light pulses would not arrive at the point simultaneously for an observer in that lab frame?

[studiot]

20 hours ago, studiot said:

You have mentioned two things without explanation.

1)

In the title you refer to The Principle of Relativity.

2) You refer to the isotropy of space.

 

Can you enlighten us as to what you think these two phrases mean please ?

Where , for instance, did they come from ?

 

@lidal

Did you miss my post ?

I asked two clear and simple questions about your statements and you have not responded in any way at all.

 

 

[lidal]

20 hours ago, studiot said:

You have mentioned two things without explanation.

1)

In the title you refer to The Principle of Relativity.

2) You refer to the isotropy of space.

 

Can you enlighten us as to what you think these two phrases mean please ?

Where , for instance, did they come from ?

The principle of relativity states that the laws of physics are the same in all inertial frames. Suppose that two physicists in different inertial frames do similar experiments. From the experiments, they formulate the laws of physics. Relativity says that both physicists will come up with and formulate identical laws of physics. An example of a law in physics is the speed of light. Relativity says both physicists will discover the speed of light to be equal to c.

Isotropy of the speed of light:

In all inertial frames, the speed of light is equal to c , and that does not depend on direction. If a physicist does an experiment to measure the speed of light in different directions in a lab, by dividing the distance travelled by light in a unit of time, he/she will always get the same result : c  .  

[studiot]

 

26 minutes ago, lidal said:

Isotropy of the speed of light:

 

Thank you for answering.

 

But your original words were

The isotropy of space  (not the speed of light)

Why have you changed it in your answer ?

And how does your definition relate to space ?  IOW how does direction relate to space ?

 

30 minutes ago, lidal said:

The principle of relativity states that the laws of physics are the same in all inertial frames. Suppose that two physicists in different inertial frames do similar experiments. From the experiments, they formulate the laws of physics. Relativity says that both physicists will come up with and formulate identical laws of physics. An example of a law in physics is the speed of light. Relativity says both physicists will discover the speed of light to be equal to c.

I don't think it mentions inertial frames or any other frames.

You would need to define an inertial frame to be able to apply such a definition.

You also face a further difficulty with such a definition.

If those two physicists measured the frequuency of a sound (or light pulse)  they will come up with different answers.

 

You are talking about what is known as form invariance.

(note Newton's Laws do not exhibit form invariance)

 

A better example, consistent with classical physics is that if they both measure the temperature of a moving object, they would come up with the same answer.

The whole issue hinges upon the observed fact that both physicists observe the same velocity for light (but not sound) despite the laws of classical physics which would suggest otherwise.

Since this was first done about 130 years ago thousands of experiments of increasing care and accuracy have been made and no one has ever found the speeds to not match exactly.

 

 

 

 

 

[lidal]

Just now, studiot said:

 

 

Thank you for answering.

 

But your original words were

The isotropy of space  (not the speed of light)

Why have you changed it in your answer ?

And how does your definition relate to space ?  IOW how does direction relate to space ?

 

I don't think it mentions inertial frames or any other frames.

You would need to define an inertial frame to be able to apply such a definition.

You also face a further difficulty with such a definition.

If those two physicists measured the frequuency of a sound (or light pulse)  they will come up with different answers.

 

You are talking about what is known as form invariance.

(note Newton's Laws do not exhibit form invariance)

 

A better example, consistent with classical physics is that if they both measure the temperature of a moving object, they would come up with the same answer.

The whole issue hinges upon the observed fact that both physicists observe the same velocity for light (but not sound) despite the laws of classical physics which would suggest otherwise.

Since this was first done about 130 years ago thousands of experiments of increasing care and accuracy have been made and no one has ever found the speeds to not match exactly.

 

 

 

 

 

But I haven't mentioned 'isotropy of space' in my OP or any of my comments. Meanwhile I will read the rest of your comments and get back to you.

No, the way I understand relativity is that  the two physicists are doing an experiment completely contained in a closed room. They are not measuring sound or light emitted from some source outside their own room. Everything, the light source, the detector etc. are contained in the room. In that case each physicist will formulate identical laws for Doppler effect of light or sound, by doing experiments in which the source is moving relative to the room. 

 

15 hours ago, studiot said:

 

 

Edited November 1, 2023 by lidal

[studiot]

1 hour ago, lidal said:

But I haven't mentioned 'isotropy of space' in my OP or any of my comments. Meanwhile I will read the rest of your comments and get back to you.

You are correct. I mentally transcribed it when I read your actual words which were isotropy of the speed of light.

Sorry about that.

But the fact remains that isotropy of the speed of light is not a necessary assumption, not was it made.

 

 

Your second paragraph however misses the entire point of an invariant.

1 hour ago, lidal said:

No, the way I understand relativity is that  the two physicists are doing an experiment completely contained in a closed room. They are not measuring sound or light emitted from some source outside their own room. Everything, the light source, the detector etc. are contained in the room. In that case each physicist will formulate identical laws for Doppler effect of light or sound, by doing experiments in which the source is moving relative to the room. 

It is vital that both physicists measure the same physical quantity possessed by the same physical object.

Otherwise there can be no comparison of anything to say that they are the same or different.

[pzkpfw]

11 hours ago, lidal said:

...

You don't seem to understand the whole point because you are busy searching the internet to find other sites where I have posted the same topic. 

I suspected and abandoned the relativistic approach from the beginning. I started with a classical approach and found a result that can divide physicists. Will the two pulses in the thought experiment arrive simultaneously or not? 

...

Ha! I'm not wasting my time searching for your spam; I happened to see it on two sites I visit most days.

There is absolutely no reason why the two pulses from S₁ and S₂ can't arrive at D simultaneously. This is not controversial at all. Further, if the ship is inertial and D is exactly between S₁ and S₂ that would mean the pulses were emitted simultaneously too - according to an inertial frame where the ship is not moving.

The real question is the view from a different inertial frame, i.e. from a frame moving according to the ship (or for which the ship is moving).

From that other frame, the simultaneous arrival is not in question. (The common example is: what if D triggers a bomb? The bomb either explodes or it doesn't, nobody can disagree.)

But according to that other frame, do S₁ and S₂ emit in sync? The answer has to be no, because the speed of light is not infinite, and D is moving towards one pulse and away from the other. The pulses have to be emitted at different times to arrive at D together.

All you have done is reverse the classic train/embankment experiment ( https://www.marxists.org/reference/archive/einstein/works/1910s/relative/ch09.htm ). Your S₁ and S₂ are the lightening strikes, and D is the observer in the middle of the train. The difference, is the strikes are stipulated to be simultaneous in the embankment frame, and the question is whether they are also simultaneous in the train frame; you have provided the vice versa - stipulating the strikes to be simultaneous in the train frame.

Where you go wrong is seen in this one line in your OP:

"It should be noted that, according to special relativity, the clocks synchronized by this procedure will be in synch. However, from experience we know that the clocks will be out of synch. Therefore, we know that the relativistic procedure is wrong, based on experience."

With the "we know" and "experience" bits you show you are assuming that there's one real truth to simultaneity, and for some reason it's not the ship that's right.

Essentially your "proof" that relativity is wrong is to assume relativity is wrong.

 

Edited November 1, 2023 by pzkpfw
typo

[lidal]

Just now, studiot said:

You are correct. I mentally transcribed it when I read your actual words which were isotropy of the speed of light.

Sorry about that.

But the fact remains that isotropy of the speed of light is not a necessary assumption, not was it made.

 

 

Your second paragraph however misses the entire point of an invariant.

It is vital that both physicists measure the same physical quantity possessed by the same physical object.

Otherwise there can be no comparison of anything to say that they are the same or different.

But Galileo's relativity is about an inertial observer in a closed room doing physical experiments contained in the room. Galileo's principle of relativity states that the observer cannot determine his motion by such experiment.

The principle of relativity is about inability to detect absolute motion inside a closed room with an experiment contained in that room. The physicist in the room does experiments by using light sources, sound sources, magnets, charges, pendulums, masses etc.contained in that room. He can then demonstrate the principle of relativity, from absence of any change in observed phenomena with change in velocity.

If the observer measures, say sound from a source on the shore, he/ she would receive Doppler shifted sound, only measuring relative velocity. How can this demonstrate the principle of relativity , that is absence of absolute motion? 

You said it is vital that both physicists measure the same physical quantity, to be able to compare what the two physicists measure. I would say that (Galileo's) relativity is about the two physicists in different inertial frames doing identical experiments contained in the labs and obtaining identical results regardless of their relative motion.

What do you mean by the observers measuring the same physical quantity? Do you mean, for example, light emitted from the same source?

So far, when I say relativity, I am referring to Galilean relativity. I am thinking about your comment in relation to Einstein's relativity and will get back to you.

 

Edited November 1, 2023 by lidal

[Bufofrog]

4 hours ago, lidal said:

The principle of relativity is about inability to detect absolute motion inside a closed room with an experiment contained in that room.

More than just absolute motion you cannot perform any experiment in a closed room that will give you a hint about your motion, assuming an inertial frame.

[studiot]

35 minutes ago, Bufofrog said:

More than just absolute motion you cannot perform any experiment in a closed room that will give you a hint about your motion, assuming an inertial frame.

That is a consequence of the P O R, not the principle itself.

Where does 'relative' or relativity come into this ?

Said locked up observer could spend his whole life in the room performing thousands of experiments and none of them would have any direct relationship to relativity, since they would all be independent of it.

 

[lidal]

@studiot

@Bufofrog

 

I think, with regard to what you said about the two physicists measuring the same phenomena, and what I said about experiments confined to the closed room, we are talking about the same idea. By a little more logic, my idea leads to yours. I will show.

 Let me first say something about the origins of relativity. Correct me if I am wrong somewhere. The principle of relativity was first proposed by Galileo. I would say that it was a very intelligent guess by Galileo, overturning thousands years of thinking. (I say this because, the principle of relativity holds to very good approximation in most systems, for example the Solar System. I am only saying that it can’t be fundamentally correct).

 I can see that when Galileo thought up this idea, about doing experiments in a closed room, he had mechanical, acoustic and other classical phenomena in his mind. Light was little understood phenomenon then. It was not even known whether light had finite or infinite speed. So Galileo couldn't have considered experiments involving light in his principle. Then Newton believed light was made of particles.

 During the intervening centuries between Galileo/Newton and Einstein, much was understood about light, such as its wave nature and speed. On the contrary, however, light also appeared to exhibit contradicting and inconsistent behavior in different experiments. The Arago and Airy experiments led to more confusions than understanding in that the speed of light couldn’t be modeled consistently according to particle theory or wave theory. Then arrived the famous Michelson-Morley experiment. The prediction of Maxwell's equations, as confirmed by light speed measuring experiments, was also a huge development.

 In the second half of the 19^th century, with the new knowledge about the phenomenon of light, scientists started reconsidering the principle of relativity. The phenomenon of light appeared to be a problem for relativity. Galileo had seen no problem with his principle.

 So what problem did the new knowledge about the phenomenon of light cause to relativity?  After all, the then new experiment, the Michelson-Morley experiment,  brought additional evidence for relativity.

 The problem was:

1. Light exhibited overwhelming wave phenomenon. Evidence: Young's double-slit experiment, Poisson’s spot,  Maxwell's equations, refraction, diffraction, etc.

 Problem: what is its medium of propagation, c relative to what?,  such medium was disproved by MM experiment.

 2. But the Michelson-Morley exp't appeared to prove particle nature.

Problem: No c+V in Maxwell's equations, conceptual problems,  

 Einstein weighed these evidences. The MM null result convinced him no absolute motion existed and he made up his mind and fully adopted the principle of relativity (PR).

 But which model of light conforms to relativity? The particle nature was consistent with PR. This had even led Einstein to consider emission theory seriously before eventually abandoning it in favor of wave theory.

Einstein's Most Famous Thought Experiment (pitt.edu)

And in wave theory, the speed of light is independent of the speed of its source, analogous to sound.

 There were also indirect and inconclusive astronomical evidences that the speed of light is independent of the speed of its source. (the Arago and the Airy experiments). Note that this is the second postulate of Einstein!. Note that terrestrial experiments to test this were yet to be performed nearly a decade later, such as by the Q.Majorana experiment.

 So far Einstein has made up his mind about two ideas: the principle of relativity and the independence of the speed of light from the velocity of its source (the two postulates!).

 Now Einstein had to reconcile these. What was the problem?

 Let us go back to the two physicists in different inertial frames doing physics experiments in closed rooms.  Now imagine both physicists doing a moving source experiment in their respective rooms. Each of them uses their own light source. Both always measure the speed of light to be c, independent of the velocity of the source relative to their room (lab).

 

Assume that room B is moving with velocity u relative to room A, as shown. The observers are at rest in each room. Assume that the light source (S_B ) in room/lab B is at rest relative to the room, but the source (S_A ) in room A is moving towards (relative to) the observer in room A with velocity u, which is equal to the velocity (u) of room B relative to room A, as shown.

Notice the openings in each room. The light of S_B goes not only to the observer in room B, but also to the observer in room A, through the holes.

The observer in A measures the speed of light from S_A to be constant c independent of the source velocity, in accordance with Einstein’s second postulate. The observer in B also measures the speed of light from S_B to be constant c. But the observer in A also receives the light from S_B through the hole. The question is: what is the speed of this light? If the velocity of light from S_B is equal to c relative to the observer in B, then according to Galilean principle of relativity, the velocity of the same light will be c+v relative to the observer in A.

Now the contradiction arises. Note that both S_A and S_B are moving towards the observer with velocity u. Even though S_B is at rest in B, because of the velocity of room B relative to room A, S_B is also moving towards A with velocity u. At this point a question may arise: why make holes in the rooms? The logic is that the observer in A can consider S_B to be in his own room, even though it is physically outside his own room.

Galilean relativity predicts that the observer in A measures the speed of light from S_A to be c and the speed of light from S_B to be c + v, even though both sources are moving with equal velocities (u) towards the observer !

Therefore, since this is a direct contradiction, Einstein would conclude that the speed of light from S_B also must be c relative to the observer in A.

But then a contradiction arises again. Observers in both rooms will measure the same velocity c of light from S_B , even though they are in relative motion ! How can two observers in relative motion measure equal velocities of the same bullet going past them?! Of course this is not true for bullets.

This is Einstein’s conclusion: the speed of a light beam is always equal to c as measured by observers in relative motion.

And how can this be? Relativity of space and time. Lorentz transformations.

13 hours ago, pzkpfw said:

Ha! I'm not wasting my time searching for your spam; I happened to see it on two sites I visit most days.

There is absolutely no reason why the two pulses from S₁ and S₂ can't arrive at D simultaneously. This is not controversial at all. Further, if the ship is inertial and D is exactly between S₁ and S₂ that would mean the pulses were emitted simultaneously too - according to an inertial frame where the ship is not moving.

The real question is the view from a different inertial frame, i.e. from a frame moving according to the ship (or for which the ship is moving).

From that other frame, the simultaneous arrival is not in question. (The common example is: what if D triggers a bomb? The bomb either explodes or it doesn't, nobody can disagree.)

But according to that other frame, do S₁ and S₂ emit in sync? The answer has to be no, because the speed of light is not infinite, and D is moving towards one pulse and away from the other. The pulses have to be emitted at different times to arrive at D together.

All you have done is reverse the classic train/embankment experiment ( https://www.marxists.org/reference/archive/einstein/works/1910s/relative/ch09.htm ). Your S₁ and S₂ are the lightening strikes, and D is the observer in the middle of the train. The difference, is the strikes are stipulated to be simultaneous in the embankment frame, and the question is whether they are also simultaneous in the train frame; you have provided the vice versa - stipulating the strikes to be simultaneous in the train frame.

Where you go wrong is seen in this one line in your OP:

"It should be noted that, according to special relativity, the clocks synchronized by this procedure will be in synch. However, from experience we know that the clocks will be out of synch. Therefore, we know that the relativistic procedure is wrong, based on experience."

With the "we know" and "experience" bits you show you are assuming that there's one real truth to simultaneity, and for some reason it's not the ship that's right.

Essentially your "proof" that relativity is wrong is to assume relativity is wrong.

 

 

Thank you for making your stand clear. I have no problem with your conclusion because a real experiment can decide between us. 

No, I didn't start from assuming that relativity is wrong. I suspected inconsistencies in the way experimental facts are interpreted in support for SRT. This led me to try abandoning the relativistic procedure and following the classical procedure, and I found a result that could make many physicists think again about special relativity. ( not including the likes of you who have stated their view in favor of relativity). 

 

 

Edited November 2, 2023 by lidal

[Bufofrog]

6 hours ago, lidal said:

This is Einstein’s conclusion: the speed of a light beam is always equal to c as measured by observers in relative motion.

Correct, an inertial observer will always measure the speed of light in a vacuum as c.  I think you got it now

[lidal]

Let me clarify the new synchronization procedure described in the OP and the difference from the standard procedure. 

In the standard procedure, the synch pulse is sent from the mid- point to the clocks at S1 and S2. The clocks, upon receiving the synch pulses, are set to t = 0 and

start counting from there. Absolute motion will have no effect in this case.

In the new procedure I have proposed (assuming isotropy of the speed of light), the clock at S1 is set to t = 0 and at the same time a synch pulse is sent from S1 to S2. The clock at S2, upon receiving the pulse, is set to t= 2D/c , and starts counting from there. This procedure will be affected by absolute motion and the clocks will be out of synch, which will manifest as time difference (at the detector) of 'simultaneously' emitted pulses from S1 and S2.

In the case of synchronizing from the center, the effect of absolute motion will be cancelled (the so-called 'two way speed of light' )

 

Edited November 2, 2023 by lidal

[studiot]

19 hours ago, lidal said:

But Galileo's relativity is about an inertial observer in a closed room doing physical experiments contained in the room. Galileo's principle of relativity states that the observer cannot determine his motion by such experiment.

Thank you for the long response.

 

Can we please separate the history of the study of the nature and propagation of light from this discussion as you have several important omissions that you are perhaps not aware of.
By itself the history is an interesting subject and we could certainly discuss that in another thread where all might learn something new.

 

As far as I know Galileo did not offer a principle of relativity.
He did, how ever offer a principle of inertia, which is what perhaps you are referring to.
But for the purposes of this thread if you know of some reference showing that Galileo made the statement you claim above please post it.

 

Neither was this The Principle of Relativity of Einstein.

His exact words from the 1905 SR paper were

Quote

...Suggest that..... the same laws of electrodynamics and optics will be valid for which the equations of mechanics hold good

We will raise this conjecture (The purport of which will hereafter be called The Principle of Relativity)...

 

No mention of physicists locked in sealed rooms determining anything!

However he adds a further comment which many readers miss, as all the words in the paper are packed with import:

Quote

The theory to be developed is based, like all electrodynamics, on the kinematics of a rigid body

I will now develop the import of this latter statement in terms of the homogeneity and isotropy of space and link that to Einsteins two postulates.

When we say there is an event such as a light pulse from your source we need to specify two things. Where is it ? and When is it?
To do this we require up to five pieces of information. These are : up to 3 spatial coordinates, one time coordinate one reference base or origin for the time coordinate and one combined reference base or origin for the spatial coordinates.

The issue of the 'absoluteness' of the references bases will come out in the subsequent treatment.

It is no use just offering x, y, z, t values  - they are meaningless without knowing where and when they are measured from.

The good news is that these last two pieces of information 'drop out' of the calculations when wew measure the distance beteen two events and the time difference between them as

l²  = (x₂ - x₁)² +(y₂ - y₁)² and (z₂ - z₁)².

and

dt = (t²  -  t¹)

dt and l are examples of invariants.

dt is invariant with regard to translations of the origin of the time axis and l is invariant with regard to translations of the space origin.

When following Einstein's original paper the significance of the second quoted remark becomes apparent.
Although the paper is entitled the electrodynamics of moving bodies, most of the paper follows their kinematics only. Dynamics is only introduced in the last two sections at the end.

Are you comfortable with the distinction between kinematics and dynamics ?

1) Homegeneity

The arbitraryness of the origins of space and time are referred to as the homogeneity of space and time respectively.

This is equivalent to postulate that every chunk of space looks and behaves like every other chunk of space and that every chunk of time looks and behaves like every other chunk of time oe in other words they are homogeneous.

 

2) Isotropy

That the length l is the same (invariant) when measured in a coordinate system that is rotated, but not translated, with respect to the first is a simple piece of elementary geometry.

This leads to the conclusion that there is no preferred direction in space. So space is regarded as isotropic.

Since space has the property if transmitting light we have your isotropic light velocity.

 

With regard to the example in your post,

Please explain why there is a problem with the observer viewing light from S1 and S2 (with the maths).

Note that we cope with this everday day almost everywhere, but it really only interests the astronomers where the distances involved makes a difference to light sources.

 

[lidal]

On 10/30/2023 at 3:43 PM, lidal said:

 A Disproof of the Principle and Theory of Relativity

Galileo’s ship thought experiment:

 Consider a light source emitting a light pulse from some point in the Earth's frame, at t=0.  At the instant of light emission, an observer/detector is at distance D from the source and is moving away from the source with velocity v, in the Earth's frame. 

 We know that the light will catch up with the observer/detector at t = D/ ( c - v ) . This is a well-known and accepted fact even in the Special Relativity Theory SRT and has been confirmed by experiments. Now I will use this in my argument against the principle of relativity.

 Consider Galileo's ship thought experiment. A physicist in a closed room of the ship is doing a physics experiment. There are two light sources S₁ and S₂, with the distance between them equal to2D. The line connecting the sources is parallel to the longitudinal axis of the ship, and hence to the velocity of the ship. S₂ is in front of S₁.  A detector is placed at the midpoint between the sources, at distance D from each of the sources. The light sources each emit a short light pulse simultaneously every second.  The detector detects the time difference between the pulses.

The observer in the closed room first has to synchronize the clocks at S₁ and S₂. For this, a short light pulse is emitted from S₁ towards S₂. Suppose that S₁ emits the light pulse at t=0. The physicist in the closed room synchronizes the clocks based on the principle of isotropy of the speed of light, because according to SRT the speed of light is isotropic in Galileo’s ship! However, unknown to him/her, we know that the clocks synchronized by this procedure will be out of synch by an amount:

                                                 (  2D/ ( c - v )  )   -   2D/c    =  2D  v / v(c-v)  

The clock at S₂ will be behind the clock at S₁ by this amount.

 It should be noted that, according to special relativity, the clocks synchronized by this procedure will be in synch. However, from experience we know that the clocks will be out of synch. Therefore, we know that the relativistic procedure is wrong, based on experience. Therefore we analyze the experiment classically as follows.

 

 

The sources each emit a short light 'simultaneously' (quoted because the clocks are not actually in synch), every second. The physicist expects the pulses to arrive simultaneously, which they do not, as we will see.

Let S₁ emit the light pulse at t = t₀. Then S₂ will emit 'simultaneously' at time,

                                            t₀  +  2D  v / v(c-v)

The light from S₁ arrives at the detector at time,

                                       t₁ =     t₀  +  D/(c -v)

The light from S₂ arrives at the detector at time,

                                   t₂ =    [    t₀  +  2D  v / v(c-v)  ]  +  D/(c+v)

The difference in the time of arrival of the two pulses at the detector will be:

                                    t₂ -  t₁  =  (2D/c) β² /(1-β² )  

where β  = v/c

The physicist synchronized the clocks by assuming isotropy of the speed of light, placed the detector at the midpoint between the sources, and the sources emitted light pulses 'simultaneously'. He/she would expect the light pulses to arrive simultaneously at the detector, which they don't. The light pulses always arrive with a time difference of Δ that depends on velocity. The observer would have no way to explain this other than abandoning the principle of isotropy of the speed of light. To anyone rejecting this argument, my response is this: let an actual experiment be done to test it. We know that the origin of the problem lies in the observer assuming isotropy of the speed of light while synchronizing the clocks. This disproves both the principle and theory of relativity.

 

 

 

Typing errors:

 (  2D/ ( c - v )  )   -   2D/c    =  2D  v / v(c-v)   2D  v / c(c-v)

 

t₀  +  2D  v / v(c-v)    t₀  +  2D  v / c(c-v)

 

 t₂ =    [    t₀  +  2D  v / v(c-v)  ]  +  D/(c+v)          t₂ =    [    t₀  +  2D  v / c(c-v)  ]  +  D/(c+v)