[dutch]

Quote from: Bored chemist on 14/08/2017 20:02:50
Quote from: dutch on 13/08/2017 23:14:17
Please stop embarrassing yourself.
I might not agree with Dutch about many things, but he's spot on with regard to Thebox.
What is embarrassing is adults on a science forum who carry on discussing fairy tales as if fact and reality.   Now I know I do not fall into that category because I have a brain in my head.

Do you even know the basics of what's being discussed in this thread?

Quote from: phyti on 14/08/2017 17:09:33
Bored chemist;
I have not seen any tables for td when slow transporting clocks.
Here is one to consider.

https://app.box.com/s/v722vkyrscqo4v5lye0j4nit05gglocy

Thanks, that's the closest anyone has yet got to answering the question I asked several pages ago.
I consider 30m/s (nearly 70MPH) rather fast for a bike.
I also considered continental drift as a possible transport mechanism...

That's for ε = ½. Now prove to me that ε ≠ ¼ etc.

Every single value of ε could be used to make a perfectly viable view of the entire universe (and does not do so for just one reference frame as we can meticulously prove the ENTIRE universe makes sense from any valid foliation/reference frame as is done in SR and GR).  ε = ½ for the local frame is merely a CHOICE via convention.

For example:

phyti's equation is    L = d/a * ( 1 - γ )

With the above if someone is assuming the gamma affects time it's implied that I ε = ½ for my reference frame and ε ≠ ½ for all other reference frame at least from "my point of view." WHY MUST THIS BE TRUE? Why does the universe give a blank about your "point of view."

Why can't my original reference frame have time dilation AND length contraction? If this is true and I accelerate to velocity v I may have NO length contraction and NO time dilation. Now one would ask: why would it take less time to travel from point A to B if there is no time dilation? Answer: Because the original reference frame is length contracted (by the exact same γ) and it takes less time to traverse the contracted distance when moving at v with no time dilation and when non contracted. The car fitting into the garage paradox in Relativity has more than one mechanism depending on the ε chosen for the frame.

Why would clock B have synchronization to clock A with the assumption ε = ½ even when ε ≠ ½ BECAUSE WE ASSUMED ε = ½ and we have no idea what ε equals. We are free to assume ANY valid convention. We are merely humans and can only know what we can prove in experiment. When infinite valid solutions exist we can't say one must be right.

We know the output t' to the entire Lorentz Equation. We do NOT know parts of it and time dilation is only a PART which includes time dilation, length contraction, changes in simultaneity, and relativistic aberration (the last one when the LT is in its entirety and includes all angles). We do NOT know any of these parts on their own because they are non-local but rather only the whole. t' is the observable output which is symmetric (t' does not equal dilated time). We are perfectly able to apply an ε where the one-way speed of light is NOT c if we wish. Given an infinite number of answers that all make sense it's only convention that we choose to use one of them locally. The choice is not handed down by a God nor does it come from experimental evidence given how Relativity works.

The below explains the twin paradox

https://en.wikipedia.org/wiki/Twin_paradox#/media/File:Rstd4.gif

In 1913, Henri Poincaré posthumous Last Essays were published and there he had restated his position: "Today some physicists want to adopt a new convention. It is not that they are constrained to do so; they consider this new convention more convenient; that is all.

[/b]

Again.........

t'/t = f'/f = (1 - v/c) / γ = γ / (1 + v/c) =  (1 - a/c)  / (1 + b/c)  γb/γa  where  v = (a + b) / (1 + a b /c²)

τ/t= γb/γa where v = (a + b) / (1 + a b /c²)    0 < τ/t < ∞

The observable output t' is the same for the same v in each form above regardless of a or b. However, the mechanism, length contraction, time dilation, simultaneity, and relativistic aberration are VASTLY different.

Now much of the above is in the context of LET (although all the same math is still used in SR) and one could argue that a block universe (fully 4D universe) does not have "real" length contraction, time dilation etc but only apparent because of rotations in a 4D structure and 3D frames are snapshots of the 4D structure. However, even then how do we know ε = ½? Why not have ε = ¼ for the block? Why couldn't we apply ε = ¼ locally to all reference frames? We definitely can.

Einstein simply chose  ε = ½ because it's the easiest convention to use.

one convention's ease of use ≠ other conventions are wrong

Please tell me how a particular convention becomes definite by experimental evidence. If you know how to do this where is your Nobel Prize?

[guest4091]

David Cooper #100;

The example you described is shown in the drawing with an arbitrary distance d.
B is moving at an arbitrary speed (.5c) relative to A. Simultaneous signals from the origin (blue) reflect from mirrors M and M'. The red curve shows the standard time unit increasing by γ as a function of speed. The length d is contracted by 1/γ, as a function of speed. The return time at D is equal to 2t.
This is part of the principle of relativity, that an observer in a moving inertial frame may consider themselves at rest, and the description of physical laws (propagation of light) are the same in any inertial frame.

https://app.box.com/s/sx7ir687lkcd89z3uqyiunw52ecv19lk

[guest39538]

Quote from: Bored chemist on 14/08/2017 20:02:50
Quote from: dutch on 13/08/2017 23:14:17
Please stop embarrassing yourself.
I might not agree with Dutch about many things, but he's spot on with regard to Thebox.
What is embarrassing is adults on a science forum who carry on discussing fairy tales as if fact and reality.   Now I know I do not fall into that category because I have a brain in my head.

Do you even know the basics of what's being discussed in this thread?

Yes indeed, my thread has been high jacked is what is the basics to this thread now. I have already said how to measure the one way speed of light.   Time dilation playing no part in my notion.

But never mind, if people can't be bothered to start their own thread, well what can I say.....

[Bored chemist]

That's for ε = ½. Now prove to me that ε ≠ ¼ etc.

What is epsilon?
You haven't explained it.

Also, I have explained exactly what I propose to do in my thought experiment.
Are you saying that the outcome isn't fixed and that if I repeat it I might get a different answer, or that there's some parameter (ε) I have missed.
Well, what is it?
Can I buy some more of it at my local supermarket?

[guest4091]

Thanks, that's the closest anyone has yet got to answering the question I asked several pages ago.
I consider 30m/s (nearly 70MPH) rather fast for a bike.
I also considered continental drift as a possible transport mechanism..

The limit of td is zero only if you don't move the clocks! To verify your experiment within life expectancy, NASA will (for a fee) place your clocks in space. You can then synch the clocks in a few seconds and be done. Think of the time you'll have for other things.

[guest4091]

Dutch #140;

Why would clock B have synchronization to clock A with the assumption ε = ½ even when ε ≠ ½ BECAUSE WE ASSUMED ε = ½ and we have no idea what ε equals. We are free to assume ANY valid convention. We are merely humans and can only know what we can prove in experiment. When infinite valid solutions exist we can't say one must be right.

This sounds so familiar! If one is right, the others are wrong. Who said that?
Why the concern of path ratios?

If Einstein is promoting the idea that A can assume a pseudo rest frame, then it's logically consistent that the time out and back are equal, thus his definition.
If A knew his absolute speed in space, he would know the ratio of the light paths out and back, yet he can establish relative simultaneity without knowing it.
 
An object at absolute rest cannot be found, but we can imagine an absolute rest frame  (arf) U for the purpose of showing the differences relative to a moving frame. Einstein then develops the coordinate transformations using c-v and c+v, i.e. light speed relative to a moving object, which can only be observed outside the moving frame.

Expressing events in the moving frames A and B in terms of U events, then allows elimination of U, and expressing B events in terms of A, and the reverse. Neither A nor B have to be an arf, but can serve that purpose if their measured speed of light is c.

The gif link in #141,  shows it makes no difference if the light paths are equal or not. The pseudo rest frame is equivalent to an arf.

[dutch]

This sounds so familiar! If one is right, the others are wrong. Who said that?

The Board Chemist....

Why the concern of path ratios?

Do you mean ε? Isn't that variable the entire point when discussing one-way speeds of light? No one is contesting the two-way speed of light independent of choice of ε so any variance in the one-way speed corresponds to different ε.

If Einstein is promoting the idea that A can assume a pseudo rest frame, then it's logically consistent that the time out and back are equal, thus his definition.
If A knew his absolute speed in space, he would know the ratio of the light paths out and back, yet he can establish relative simultaneity without knowing it.

Please allow me to rewrite this with more accurate language:

If Einstein is promoting the idea that A can (but does NOT have to. remember can ≠ must) assume ε = ½ for their own reference frame, then it's logically consistent that the time out and back are equal under this assumption (which is completely circular but OK), thus his CONVENTION.
If A knew his true value for ε (if such a thing exists), he would know the true one-way speed of light (if such a thing can be absolutely defined), yet even if he doesn't know ε he can use a convention that assumes any ε he pleases.


To prove to me the one-way speed of light is c you must either:

1) Synchronize clocks with an instantaneous light signal.

2) Provide a way to synchronize clocks not based on convention.

You must prove what a "now" is definitively in two spatially separated locations experimentally.

We must have FTL signaling to say anything further on the one-way speed of light (or anything for that matter). We simply form a convention for one-way speeds nothing more. 

What is epsilon?
You haven't explained it.

I explained it, I gave an equation for it, I gave links to references discussing it, and I used it multiple times in many posts. I'm not explaining it again so you can just ignore it.


How does anything anyone's written change the answer I originally gave in my first post in this thread?

[Bored chemist]

E=MC² doesn't tell me what energy is.
"Energy is the capacity to do work" does.
So, the equations  don't actually explain epsilon.
Setting that aside for the minute, As I said earlier (and you don't seem to have noticed) I'd really like an answer to my question.
If I did the experiment I proposed,
and then did it again,
one of two things would happen.
I'd get the same answer both times, or I wouldn't.
Which would you expect?
Would the experiment be repeatable?

[David Cooper]

When infinite valid solutions exist we can't say one must be right.

This sounds so familiar! If one is right, the others are wrong. Who said that?

There aren't infinite valid solutions - there are merely infinite potentially-valid solutions, all of which contradict each other and only one of which can actually be a representation of the actual reality.

[dutch]

Quote from: phyti on Yesterday at 15:23:34
Quote
When infinite valid solutions exist we can't say one must be right.

This sounds so familiar! If one is right, the others are wrong. Who said that?

There aren't infinite valid solutions - there are merely infinite potentially-valid solutions, all of which contradict each other and only one of which can actually be a representation of the actual reality.

Maybe and I personally would like to think so. However, we can't prove any particular solution correct but we can point out that Einstein Synchronization where ε = ½ for our own frame is an agreed upon choice AKA a convention.

https://en.wikipedia.org/wiki/One-way_speed_of_light   There's 49 different sources on this wiki page and I've seen many more.

The two way speed of light in a vacuum as measured in two (inertial) coordinate systems moving with constant relative velocity is the same regardless of any assumptions regarding the one-way speed.[48]

[/b]

Even from Einstein's convention ε ≠ ½ for all other frames given ε = ½ for our reference frame from our view. Yet surprisingly (sarcasm)... the laws of physics still work for all frames.

It's not enough for me to accept Einstein Synchronization as anything more than convention unless all other conventions are shown to be invalid. Without having a unique synchronization or instantaneous signaling I'm not about to commit to ANY ε and thus ANY value for the one-way speed of light for any reference frame. I often use Einstein Synchronization simply because it's convenient.

[Bored chemist]

If I did the experiment I proposed,
and then did it again,
one of two things would happen.
I'd get the same answer both times, or I wouldn't.
Which would you expect?
Would the experiment be repeatable?

[guest39538]

If I did the experiment I proposed,
and then did it again,
one of two things would happen.
I'd get the same answer both times, or I wouldn't.
Which would you expect?
Would the experiment be repeatable?

If your experiment was set up correctly the same as my experiment would need to be, then you should expect repeat results if c is constant that was an identical result every time.


However, the atmosphere is not a vacuum. You need to do it in a vacuum.

[Bored chemist]

If I did the experiment I proposed,
and then did it again,
one of two things would happen.
I'd get the same answer both times, or I wouldn't.
Which would you expect?
Would the experiment be repeatable?

If your experiment was set up correctly the same as my experiment would need to be, then you should expect repeat results if c is constant that was an identical result every time.


However, the atmosphere is not a vacuum. You need to do it in a vacuum.

That's a start.
I wonder if Dutch agrees.
If I do the experiment of synchronising two clocks (next to each other) then moving them slowly then using them to time the arrival of a flash of light- with all the details I previously specified.

And then I repeat it.
Will I get the same answer twice?

[guest39538]

So, as you say:
The one-way speed of light everything: whether it's light, or the number nine bus is simply impossible to measure without applying an arbitrary convention by any known means.

When you fix the problem of t=speed/d   to something independent instead, then you can measure the one way speed of anything.

[dutch]

That's a start.
I wonder if Dutch agrees.
If I do the experiment of synchronising two clocks (next to each other) then moving them slowly then using them to time the arrival of a flash of light- with all the details I previously specified.

And then I repeat it.
Will I get the same answer twice?

Before I answer your question again... let me ask one of my own.

If I have the equation X + Y = A and X and Y could be anything what is X?

The answer you will give based on your history in this thread is X = Y. X and Y could be anything so without extra information this could be correct and maybe it is. Perhaps X always equals Y... perhaps. HOWEVER, there are infinitely many other answers. Without more information we could just make the equation easier by saying X = Y and thus 2X = A but this is just a convention.

Now onto your question:

For the hundredth time you are confusing t' with τ. Watch the math carefully:

I could say t' = γ t   = 1/.8 √(1 - .8^2) = .75

Or I could say

t' = ( t - v x ) / γ = (1/.8 - .8 * 1)/√(1 - .8^2)  = 2.083333 - 1.3333333 = .75

Wait would you look at that! They're EQUAL.

The time dilation on the first one is γ   and the second one is 1/γ. The τ are  γ t and t/γ which are NOT the same. The t' IS the same. The two forms above are COMPLETELY different mechanistically.

The entire point of the v x /c² / γ term is to account for frames of different ε which relativity is forced to do (even if they push them to "other" reference frames). Now watch:

½ ( x γ / ( c + v ) - x γ / ( c - v ) ) = ½  x γ * [ (c - v) - (c + v) ] / (c² - v²)

= - ½ x γ  2 v / (c² - v²)

= - v x γ / c² / [ (c² - v²)/c² ]

= - v x / c² / γ     (this is the fudge factor or the time added subtracted to a clock to keep it synchronized as viewed
                          from an ε = ½ frame)

The above gives the EXACT same answer. Let's define ε here as:

ε = t1 / (t2 + t3) = x γ / ( c - v ) / [ x γ / ( c - v ) + x γ / ( c + v ) ]

= 1 / ( c - v ) / [ 1 / ( c - v ) + 1 / ( c + v ) ]

= 1 / ( c - v ) / [ ( c + v ) / (c² - v²) + ( c - v ) / (c² - v²) ]

= 1 / ( c - v ) / [  2c / (c² - v²) ]

= (c² - v²) / [ 2c (c - v) ]

= ½ c (c² - v²) / [ c² (c - v) ]

= ½ c γ² / ( c - v )

= ½ c² γ²  ( c + v )    / [ c ( c² - v² ) ]

= ½ γ²  ( c + v )    / [ c γ² ]

= ½ ( 1 + v/c ) 

This is just ONE formula for ε given a v and there are infinitely many more that can give ANY ε for any v. (generalized equation found in link below)

https://en.wikipedia.org/wiki/One-way_speed_of_light

Why can't I choose another valid ε than ε = ½? Where does my formula for t' fail? If it does not fail then why can't I use it?

Relativity says I CAN always choose ε = ½ for any reference frame locally but it does NOT say I can't choose any other ε. It simply forms a nice convention which greatly streamlines calculations.

The ONLY way I'm going to agree with you is if you prove I MUST choose ε = ½ and all other ε are invalid. Otherwise I must conclude one-way speeds which require a definitive way to synchronize two spatially separated clocks (or send an instantaneous signal) are undefined outside of a convention. "Relative" synchronization via an arbitrary convention is just not good enough.

I ALREADY showed the term -v x / c² / γ and I said it explained how I could choose other ε. I already explained how it depends on x. Considering this term is straight out of the Lorentz Transformation and in both LET and SR you can't deny it's authenticity. You also can't deny that ε ≠ ½ for one of the two frames in the transformation. Nothing stops me from choosing one ε from infinitely many ε.

Considering we do NOT know how to send signals instantaneously and infinitely many planes of simultaneity (foliations in GR) exist and ALL can individually explain the universe we CANNOT know what "now" is in two spatially separated locations. If we don't know what "now" is beyond convention then we don't know one-way speeds (don't forget how I defined v as a two-way average velocity in prior posts).

I also don't care about "slow clock transport" there's a multitude of reasons (many I already gave) on why slow clock transport should be the same as fast clock transport as experiments show. This point you keep trying to make has nothing to do with my freedom to choose ε.

I will never agree with you unless someone gets a Nobel Prize for ending a 110 plus year old debate. I already gave links to all of this and equations. Don't confuse a cute convention with something absolute.

[Bored chemist]

Here's a hint.
The answer to this question is "yes" or "no"
If I do the experiment of synchronising two clocks (next to each other) then moving them slowly then using them to time the arrival of a flash of light- with all the details I previously specified.

And then I repeat it.
Will I get the same answer twice?

[dutch]

Here's a hint.
The answer to this question is "yes" or "no"
If I do the experiment of synchronising two clocks (next to each other) then moving them slowly then using them to time the arrival of a flash of light- with all the details I previously specified.

And then I repeat it.
Will I get the same answer twice?

What is your problem now? I've already given multiple equations for t'. The t' you show doesn't prove what you think.

The question of X + Y = A and we know A does NOT have anything to do with a statement X = Y. You want ε = ½ and I'm saying it could be BUT it does not have to be. You are NOT synchronizing clocks beyond convention because the term - v x / c² / γ tells you that your synchronization is off via the perspective chosen and exactly how much it's off. Other equations for ε also exist and I can assume any ε I wish for any frame I wish. Just because you can choose ε = ½ for your frame does NOT mean you have to. This does not prove Einstein's postulate wrong because a postulate means that you can assume something and always get an answer that works. The postulate does not necessarily mean you can't make other assumptions and scientists have shown you can (and no one has ever shown you can't).

You must be looking at the situation classically where all four relativistic changes (length contraction, time dilation, change in simultaneity, relativistic aberration) do not occur. Repeating your question when I've answered it a dozen times with math and links isn't going to go anywhere for you.

Do you KNOW what happens if an instantaneous signal is sent?

How do you KNOW what a one-way speed is beyond convention if you don't know what happens with an instantaneous signal? We've never experimented with instantaneous signals so we don't know what now is in two different locations. I don't make judgement without experimental evidence. Do you know of any experiment proven to send any information faster than light? If not then you can't provide me anything more than an answer based on convention. What is wrong with the answer "gee we just don't know?"

What is your problem with the statement below?

We can measure the one-way speed of light (or anything) to significant accuracy but only with respect to our choice of convention.

[Bored chemist]

I have never claimed that an instant signal is sent.

Well, I have said that if you press the two "reset" buttons on the clocks against one another  it is one action and it is local to both clocks and, since it's the same act it is simultaneous with itself for all observers because the alternative would be a violation of causality.

And  I have said that , if you have two perfect clocks next to each other, set to "zero" at the same time, they will stay synchronised.
And I have said that, if you move one of them, it will run slow, but if you move it slowly it will not lose much time (and someone kindly provided a table of how slow it would be).
So, since you know how slow it is, you can allow for that.

You keep going on about conventions; well I have tried to define mine.

You keep telling me that the apparent speed depends on epsilon.
I  keep asking you if  the apparent speed of light I measure will be  consistent and, rather than saying yes or no, you keep telling me that instant messaging isn't possible.
Well, I know that- and I never said it was.

So, yet again

If I do the experiment of synchronising two clocks (next to each other) then moving them slowly then using them to time the arrival of a flash of light- with all the details I previously specified.

And then I repeat it.
Will I get the same answer twice?

[dutch]

You keep going on about conventions; well I have tried to define mine.

So it's a convention. CASE CLOSED my first post stands correct. Good bye.

[guest4091]

The box #121;

Einstein never considered the two way journey of light in his ideas .  If he had , he would of known and realised that simultaneity is nothing to do with different now's or different rates of time

.

Do more research.
1905 paper, par. 1, 2; A. Einstein:
We have to take into account that all our judgments in which time plays a part are always judgments of simultaneous events.
We have so far defined only an ``A time'' and a ``B time.'' We have not defined a common ``time'' for A and B, for the latter cannot be defined at all unless we establish by definition that the ``time'' required by light to travel from A to B equals the ``time'' it requires to travel from B to A.
So we see that we cannot attach any absolute signification to the concept of simultaneity, but that two events which, viewed from a system of co-ordinates, are simultaneous, can no longer be looked upon as simultaneous events when envisaged from a system which is in motion relatively to that system.