# One-Way Speed of Light

Another make it or break it experiment for TOEBI is the following one-way speed of light experiment. Measuring the one-way speed of light won’t be as trivial as one might initially think, check out the Wikipedia article for more information.

My claim, based on TOEBI, is that the one-way speed of light won’t be the same in all inertial frames and to my surprise the following experiment has never been done.

Let’s have a train (our inertial frame) moving with a constant velocity $\vec{v}$. Then we set up two light detectors, say 30 meters apart and mark up the spot X in between the detectors having an equal distance (15 m) to the detectors. At spot X we synchronize two atomic clocks and move them next to the detectors with the same, very slow, pace. Detector and atomic clock pair functions so that when light is detected then atomic clock records the time of the event.

Then we set up our light source on spot X and start making events. According to relativity theories those recorded times should be exactly the same, but according to TOEBI that won’t be the case. How come? That’s because photons move through FTE, in our case, FTE provided by Earth. Inside FTE, photons move at speed $c$ as expected but the problem obviously arises in our experiment. If the train moves at speed $v$ and photons at speed $c$ then photons will reach the rear detector sooner than the front detector, but Einstein disagrees, without any experimental backup.

Synchronization of the atomic clocks was performed as relativity theories would require in order to keep those clocks synchronized. In reality, it would be sufficient to put all those equipment in their proper places before the train leaves a station. Acceleration of the train won’t unsync those clocks even though equivalence principle “dictates” so, once again, no proof exists for unsynchronization in case like this one (a.k.a. acceleration happens perpendicularly to a gravitational field).

## 44 thoughts on “One-Way Speed of Light”

1. Berry says:

> Acceleration of the train won’t unsync those clocks
> even though equivalence principle “dictates” so,

It does? Please elaborate.

2. Berry says:

Ah, yes, the equivalence between acceleration and gravity, right. Hence, according to TOEBI this equivalence is invalid?

3. Yes, when the acceleration happens perpendicularly to a gravitational field (i.e. the train case).

4. Berry says:

If it’s invalid, than it’s invalid and would affect an acceleration parallel to gravitation just the same.

But why do you suggest this complication “in reality” at all? On the contrary, in terms of a clean experiment, it would be much more sensible to “put all those equipment in their proper places” when the train is already running.

But all this is irrelevant, because you’re not going to do the experiment anyway, right?

5. In parallel case too it’s invalid (my claim) if there is no gravitational field present. I just wanted to mention the claim because that’s testable too.

Doing this experiment(s) requires too much resources so it’s definitely out of my league.

6. Berry says:

> In parallel case too it’s invalid (my claim) if there is no gravitational field present.

If there is no gravitational field present, then parallel is undefined.

> I just wanted to mention the claim because that’s testable too.

But you know that tests of the strong equivalence principle have been done?

> Doing this experiment(s) requires too much resources so it’s definitely
> out of my league.

And you’re still sure that equivalent experiments haven’t been done, yet?

7. LOL, indeed, I must have been in sleep or something when I wrote that.

I can’t find any experiment proving the supposed clock unsync due to acceleration…

8. Berry says:

> I can’t find any experiment proving the supposed clock unsync
> due to acceleration…

Attention, it’s not the acceleration itself, which causes the
desync. It’s special relativity involving curved world lines (as
opposed to its common thought experiments). But naturally, when doing
real experiments like the famous one of Hafele and Keating, curved
world lines must be and are taken into account, and always agreement
with relativity was found. Hence, unlike TOEBI, this prediction is
not without experimental basis.

But I didn’t mean to refer to this unnecessary acceleration
complication but to your allegedly unprecedented experiment, which
actually is a one way speed isotropy test. So, what is the
frame, where you claim TOEBI to predict isotropy? Earth’s surface?

9. Did Hafele-Keating measure the desync of the clocks on board? I don’t think so.

You mean unisotropy? In our case, the train (frame) moving on Earth’s surface.

10. Berry says:

> Did Hafele-Keating measure the desync of the clocks on board?
> I don’t think so.

No, but they (and successors) confirmed the predictions of
relativity for world lines being even more complicated
than the one you pointed out.

> You mean unisotropy? In our case, the train (frame) moving on
> Earth’s surface.

No, I meant isotropy. Don’t you claim isotropy for any train not
moving , i.e. not moving with respect to earth’s surface?

11. Berry says:

Yes, Kimmo, we’ve got that. And doesn’t that imply isotropy for a non-moving one? Non-moving with respect to earth’s surface, that is.

12. Berry says:

… which ist not only strangely and suspiciously geocentric, but already ruled out by experiments: Earth’s rotation makes its surface a non-inertial one and breaks east/west-symmetry (cf. e.g. http://journals.aps.org/prd/abstract/10.1103/PhysRevD.18.2173)

What’s the point of this whole post, anyway, Kimmo? You won’t do the Experiment, anyway, and there are already enough other issues, where TOEBI contradicts mainstream physics (including experiments).

13. Geocentric in our case, every stellar object provides the same circumstances. I’ll check up the link later today.

14. ABSTRACT
A pair of clocks, attached to a uniformly rotating frame, can be synchronized so that the one-way speed of light is the same in both directions and is time independent.

Received 3 February 1978

So? I haven’t claimed that the one-way speed of light won’t be the same while standing here on Earth. My experiment is all about moving within the FTE provided by i.e. Earth.

What’s the point of this whole post, anyway, Kimmo?

I just wanted to let my readers know about this potential experiment. Talking about experiments I have planned to run my reduced FTE density experiment within a week.

15. Berry says:

> every stellar object provides the same circumstances

Yeah, and they’re all independent, sure thing. That is, the FTPs coming e.g. from the moon have no influence here, right?

Once more: What are you trying to accomplish with this post?

16. Berry says:

(Forget my “Once more: …”, sorry, our comments have criss-crossed.)

But experiments addressing this aspect have already been done, also with sources moving tangentially with respect to earth’s surface, like GPS satellites as in http://www.sciencemag.org/content/228/4695/69
And again they have found nothing than agreement with relativity (including the east/west-asymmetry), while TOEBI contradicts relativity (as if it hadn’t already enough problems).

> Talking about experiments I have planned to run my reduced FTE density
> experiment within a week.

I’m staying tuned.

17. Yeah, and they’re all independent, sure thing. That is, the FTPs coming e.g. from the moon have no influence here, right?

Surely those affect but Earth’s velocity around the Earth-Moon barycenter isn’t that significant.

That linked experiment is about Sagnac effect.

18. Berry says:

> Surely those affect but Earth’s velocity around the Earth-Moon
> barycenter isn’t that significant.

Of course, you surely have calculated this insignificance in numbers, right? Furthermore, much more important, anyway, would be earth’s rotation interfering with the alleged FTP-jet received from moon, i.e. for a frame resting on earth’s surface, there should be a daily or diurnal perturbation of it being a “zero-frame”.

> That linked experiment is about Sagnac effect.

Sure, that plays naturally a major role in it. So? Does this rule out any relevance for your proposed experiment? They measured the speed of signals in different directions, originating from sources moving tangentially with respect to earth’s surface and found no deviations from relativity. That’s still compatible with TOEBI’s prediction of Galileian addition of velocities, really?

19. That barycenter is inside Earth so “orbiting” it gives negligible velocity (a.k.a. effect ) for the experiment.

But what they measured was in practice the two-way speed of light.

20. Berry says:

> That barycenter is inside Earth so “orbiting” it gives negligible
> velocity (a.k.a. effect ) for the experiment.

Firstly, as already told, their mutual orbiting (and thus the barycenter) is irrelevant for the daily or diurnal perturbation. That’s because the latter would be due to earth’s rotation. Secondly, experimentalists nowadays can detect the influence of relativity due to height differences of <1m and velocities <10m/s (http://www.sciencemag.org/content/329/5999/1630). And since you have no mathematical basis for your predictions, you have no actual estimation about the negligibility, anyway.

> But what they measured was in practice the two-way speed of light.

So does your proposed experiment. Nice try, but I’m not inclined to discuss this subtlety of relativity with you. Instead, we can have it much simpler:

We place your train at rest on the equator, the beam directions being east and west. We put two mirrors symmetrically into the path of the beams (i.e. one further east, the other the same distance further west) in order to prevent the beams from escaping into outer space. We place another pair of mirrors, also symmetrically and with the same purpose, and so on, all along the equator. You claim TOEBI to predict symmetric speed of light for this case, which is not broken by the symmetric chains of mirrors. Thus, the light signals should arrive at the antipodal point at the same time. But this is experimentally known to be wrong since over 40 years.

21. Eh, I don’t claim that signals should arrive at the same time in experiments of yours, Sagnac effect applies. If I were you (or any other university physicist) I would conduct the experiment and challenge Einstein big time. Eventually somebody’s going to conduct the experiment and get the attention, naturally I hope it would be you or your group.

22. Berry says:

> I don’t claim that signals should arrive at the same time in experiments of yours

How not? What breaks symmetry?

23. Berry says:

How that?!?

Let’s get this straight: For a resting train, we place it at $w_0=e_0=0$, you confirmed isotropy (“Absolutely”), meaning a signal velocity of $c$ in all directions. Let the first mirrors be placed at $w_1=-L$ and $e_1=L$, then the arrival times at the mirrors are $t_w=L/c$ and $t_e=L/c$. Where do you disagree?

24. But due to Earth’s rotation those times won’t be the same, it will take more time for the signal to reach the mirror at east. However, the speed of light stays the same.

25. Berry says:

> But due to Earth’s rotation those times won’t be the same, it will
> take more time for the signal to reach the mirror at east.

Why should that be the case?!? Does TOEBI goof up simple kinematics as well?

a) The speed of light is $c$ with respect to the resting train, yes or no?
b) The mirrors are resting with respect to the train, yes or no?
c) => The speed of light is $c$ also with repect to the mirrors, yes or no?

26. a) two-way speed of light, yes
b) yes
c) two-way speed of light, yes

27. Berry says:

Thus, when you write “Inside FTE, photons move at speed $c$” then that’s not a statement about their one way velocity? A TOEBI photon starting at time $t=0$ at position $x=0$ is later not found at $x(t)=ct$?

Or, equivalently, what time does a TOEBI photon need to travel a distance $L$?

28. Thus, when you write “Inside FTE, photons move at speed $c$” then that’s not a statement about their one way velocity?

Sure it is, photons progress in FTE exactly the speed $c$. Naturally objects (i.e. mirrors) are able to move during the time of photon’s flight.

29. Berry says:

> Sure it is, photons progress in FTE exactly the speed $c$ .

Then, why do you restrict the answers a) and c) to “two-way speed”? (Other than for weaseling purposes, that is.)

> Naturally objects (i.e. mirrors) are able to move during the time of photon’s flight.

They are able to move, sure, but they don’t need to and in our case they don’t do move. I.e. source does not move, mirror does not move, and they are a distance $L$ apart. Then, why doesn’t TOEBI light take the time $L/c$ for the travel?

30. Then, why do you restrict the answers a) and c) to “two-way speed”?

Because I think you are using two-way signal for the direct measurement of $L$.

Mirrors and source are moving at the same pace because Earth is rotating but light travels with speed $c$.

31. Berry says:

> Because I think you are using two-way signal for the direct
> measurement of L.

I most certainly don’t, because we are doing this thought experiment in TOEBI world, where “Lorentz Factor is Bull’s Shit” and where a photon is just a bunch of classical particles.

> Mirrors and source are moving at the same pace

They’re moving at the same velocity in any frame, sure. This includes the specific frame we’re dealing with, namely earth’s surface, where the speed of light is isotropic (as you claim TOEBI to predict) and where they both have $\vec v=0$. What else would “a train at rest” denote? It’s the case $\vec v=0$ in “moving with a constant velocity $\vec v$”, as you’ve already confirmed in answers a) and c).

Kimmo, don’t you think you’re exaggerating this self-contradictory weaseling a bit?

32. I’m sorry, I have to correct my previous statement… one-way speed of light is not isotropic on Earth surface (frame). However, it’s isotropic inside any FTE.

Weaseling… I have presented an experiment which might prove my idea right.

33. Berry says:

> one-way speed of light is not isotropic on Earth surface (frame).

Which in turn means that the statement about TOEBI world “If the train moves at speed v and photons at speed c then photons will reach the rear detector sooner than the front detector” is not true in general! And that your above answer “Absolutely” is obsolete. Right?

> However, it’s isotropic inside any FTE.

Then, what kind of frame is “FTE provided by Earth”? What’s its motion compared to rotating earth?

34. Then, what kind of frame is “FTE provided by Earth”? What’s is motion compared to rotating earth?

Center of mass kind of frame.

…then photons will reach the rear detector sooner than the front detector” is not true in general! Right?

Right.

35. Berry says:

> Center of mass kind of frame.

That means, not following earth’s own spin, just following earth around the sun, right?
Then, the anisotropy can be made specific: $t_W<t_N=t_S<t_E$, which are the travel times for signals from a source resting at the equator to four targets (all in the same distance $L$ from the source). Right?

> Right.

And that your above answer "Absolutely" is obsolete. And that you didn't provide the correct experimental outcome according to TOEBI, yet. Right?

36. Berry says:

“And that you didn’t provide the correct experimental outcome according to TOEBI, yet.”

That was misleading, it should read “And that you didn’t provide the correct prediction according to TOEBI, yet.”

37. …which are the travel times for signals from a source resting at the equator to four targets (all in the same distance L from the source). Right?

Right.

And that you didn’t provide the correct prediction according to TOEBI, yet. Right?

That’s right, but I will after I’m done with the reduced FTE experiment. Which, by the way, is bound to happen tomorrow.

38. Berry says:

> Right.

And with a mild helping of industriousness, one can even find out that $t_N+t_S<t_W+t_E,$ i.e. by comparing a round trip W-E-W (or E-W-E) to N-S-N (or S-N-S), one could detect (accordingt to TOEBI) the presence of a relative velocity $v$. Did you ever hear about such kind of experiments having been done?

> That's right, but I will after I'm done with the reduced FTE experiment.

I reckon, it won't be necessary.

> Which, by the way, is bound to happen tomorrow.

I'm still tuned. Will the experiment's description be fastidious?

39. I had some technical difficulties with my experiment. My Americium-241 was too heavily covered hence detecting gamma-rays was at poor level. But anything fancy didn’t show up. I’ll tweak my setup a bit in next day or two.

40. Berry says:

> My Americium-241 was too heavily covered hence detecting gamma-rays
> was at poor level.

That should be the topic over there.

Here, the current question is: Would it be something new to experimentally compare $t_N+t_S$ to $t_W+t_E$? Do you really think that?

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