# Is time universal? NO (and its proof)

Raphael said:
It is impossible to measure the SOL without first knowing the value of the meter. By definition, it is impossible to know the value of the meter, without first knowing the SOL.
Consider when the platinum-iridium metre prototype was the standard.

It's impossible to measure the distance between the marks without first knowing the value of the metre.
By definition, it was impossible to know the value of the metre, without first knowing the distance between the marks.

What's wrong with this argument?

Pete said:
I think the only time I've ever seen a slide rule is when learning logarithms in school. Nearly 20 years ago...
I still occasionaly use mine. Paid \$25 for it from my paper route earning about 60 years ago. It was the latest, magnisium K&E "log log deci trig" as we said back in the dark ages: "the cat's meow"

Pete said:
It doesn't have to be given in meters per second.

Yes it does. Even if you start out with the permittivity (F/m or m<sup>−3</sup>·kg<sup>−1</sup>·s<sup>4</sup>·A<sup>2</sup> ) and permeability (N/A<sup>2</sup> or m·kg·s<sup>−2</sup>·A<sup>-2</sup>)of free space you are left with m/s after the calculation ( c = 1/&radic;(&epsilon;<sub>0</sub>&mu;<sub>0</sub>)) is made.

Physics Monkey said:
</em>Hi Neddy,

There is actually no contradiction because you've missed another asymmetry between the front and back filters. The back filter is coming towards the light pulse and the front filter is running away from the light pulse. So there is the source asymmetry you've mentioned, but there is also this detector asymmetry. And as I said, this is one of the keys to laser cooling: the lasers are adjusted so that atoms coming toward the laser (i.e. trying to escape the trap) are resonant and interact strongly with the laser where as atoms moving away from the laser interact weakly and feel very little force.
Hi Physics Monkey,

Thanks for the clarification. It makes more sense now. I think I read too much into the following (emphasis mine):
Billy T said:
</em>Indeed, the energy and color of the photons is "frame dependent" (normally referred to as red and blue shift.)...

...As the train moves in the embankment frame while the light* is traveling towards the photo detectors the train end approaches the oncoming light and the front of the train moves further away...

_____________________________
*Which admittedly will be absorbed only in train mounted photodectors (but they are sensitive to all colors of light...)
My misinterpretation was that there would be doppler-shifted light arriving at the color-filtered detectors in one frame, while unshifted frequencies arrived in the other frame. If that were the case, we might have a causation problem (because we cannot have an explosion in one frame but not the other).

Physics Monkey said:
</em>...If there is an explosion in one frame, there is going to be an explosion in the other.
Yes, absolutely. That is why I began to entertain the idea that perhaps the band-pass frequency of the moving filters might relativistically "dilate" to a broader frequency range -- so that the explosion would not be frame dependant due to the doppler-shifted light. Now it seems that the light's frequency at the detectors is essentially the same in both reference frames.

The bypass frequency 'dilation' concept turns out to be unnecessary. I knew I should not bother to clear a spot on my trophy shelf for that one, but it was a neat idea anyway.

Raphael said:
Yes it does. Even if you start out with the permittivity (F/m or m<sup>−3</sup>·kg<sup>−1</sup>·s<sup>4</sup>·A<sup>2</sup> ) and permeability (N/A<sup>2</sup> or m·kg·s<sup>−2</sup>·A<sup>-2</sup>)of free space you are left with m/s after the calculation ( c = 1/&radic;(&epsilon;<sub>0</sub>&mu;<sub>0</sub>)) is made.
If you want it in SI units, sure... but that system is explicity based on a Mass-Length-Time dimensioning model, and the metres/second expression for the speed of light is just an artefact of that model.

Other models would work just as well, I think.
Certainly Mass-Speed-Time, or Mass-Speed-Length would work.
Perhaps Energy-Momentum-Speed? Energy-Momentum-Time? Mass-Energy-Momentum? I'm not sure about those!

Billy T said:
Not so. No one is denying that you can cover one or both photo detectors with some film or filter which will cause one or both of the explosions to not occur. (Black paint on the photocell cover should do that well.) What does that prove? The color of the light as it arives at the photo cell triger is not important, if it still can trigger the explosion.

Boy you are sensative aren't you. You might try being just a bit more professional. "Black paint". HeHe really now. :bugeye:

All that mater is the time of flight. Don't fall for MacM's "different energy photons" crap.

And don't fall for Billy T's "Black Paint" is the same as red and blue filters on the triggers. It isn't. The red and blue trigger filters seperate the rest frame from the moving frame. All of a sudden the same photon idea causes an explosion in one frame but not another. Hmmmm.

MacM is trying to imply that different energy photons move at different speeds

I never implied any such thing. It can move just as it has moved before installing the filters on the triggers. This is not about changing the timing of the events as viewed by observers in different frames but showing that the event occurs in one frame and is merely observed in the other.

This is a thought experiment - that means you think and focus on the essentials, not the details of how.

Right and lets only think the thoughts allowed by the presenters of the scenario. Any thoughts that upset the presenters conclusions must be rejected. Shsssh. HeHe. I love this you know Billy.

I will belive MacM's different colors (or energy) photons travel at different speed when suppernovas are initially one color and for a few weeks continuously change to a different color, due the MacM's differ energy photons travel differently!

I'll let you know when I ever propose any such thing. THEN you can post comments like these.

Billy, Dale and Pete,

"It is impossible to measure the SOL without first knowing the value of the meter. By definition, it is impossible to know the value of the meter, without first knowing the SOL. "

The second sentence is rubbish. I am not entirely sure where that came from. I am pretty sure it was an uneditted stray thought which made its way to my fingers. But I need to sort through this maelstorm of thoughts in my head and think about things to make sure it wasn't something intertwined with "more important" thoughts. That'll teach me to try to post on this board when I distracted by pain (crazy weather changes + bad ankle). I don't even know what side is up right now without checking for a label.

Be good guys, I'll be back after considering a few things and with luck that will correspond to the weather deciding it is either going to be cold or warm.

I Want That We Should First Have A General Agreement On How To Definr Time.ifnot Then Our Arguments Would Be Inconsistent In That Case Becuese Each Person Would Have A Diffrent Definition To Time.
Scientist Have Agreed, Time Is A Measurement Of The Earths Movement With Respect To Change In Days And Nicht, And To It's Distance From The Sun. So Then It Measures The Speed Of Rotation Of The Earth.we All Know That Moving Towards The West We Loose Time And Towards The East We Gain Time.(u.s Is 6hrs Behind The G.m.t).this Is Because The Earth Rotates East To West, Meaning The Eastern Side Will See The Sun(gain Time) Before The Western Side. Given That, The Earthrotates In A Diffrent Manner And Speed From Other Planets In The Universe Then We Should All Agree Tha Time Is Not Universal.

Raphael said:
Be good guys, I'll be back after considering a few things and with luck that will correspond to the weather deciding it is either going to be cold or warm.

Low 70'sF and dry here.

MacM said:
...the event occurs in one frame and is merely observed in the other....
Here you seem to be trying for duck and weave 17. (Are you never satisfied with your already untouchable record of 16?)

It was bad enough when photons only belong to only one frame, but now Events only occur in one frame also? Please help me understand with the following specific example:

Man and a "clay pigeon launcher" (used for duck hunting practice) are riding on a flat-bed railroad car, all traveling at 50mph horizontally. Clay pigeon was launched in same direction as train, with initial horizontal speed, wrt ground, of 80mph (essentially 30mph wrt train) and unspecified vertical speed. The man later fires his rifle, at it well (bullet hits clay target).

The bullet was traveling at 50 mph horizontally wrt to ground initially when it left the rifle as the man fired it "straight up" (for him) but wrt ground it initially also has the train's 50 mph horizontal speed. However air resistance to this forward ground speed slow the horizontal component of the bullet's speed down to only 35mph wrt to the ground when it hit the clay pigeon. (-15 mph wrt to train.)

In all frames (except its own) the bullet is going 200 mph vertically wrt to the flat land when it collided with the clay pigeon AT THE PEAK of clay pigeon's vertical trajectory, producing the "smashing event." (Hence, I did not specify the initial vertical component of the clay pigeon’s speed but you can select any reasonable one, if you like.)

At the time of the "smashing event" the clay pigeon had slowed to only 40mph wrt ground (all horizontal as it is at peak of trajectory, and of course -10mph wrt to man and train).

Now please tell me in which of the various possible frames did the "smashing event" occur?

I.e. wrt a small brick resting on ground between the two train rails, give the vertical (if any) and horizontal (if any) speeds of the Cartesian coordinates of the origin of the frame of the “smashing event.”

Please also tell why the “smashing event” occurred only in the frame you specified.

Oh, I do love trying to torture you, as well as exposing nonsense, but expect I will fail. I.e. you will happily reply and get credit for duck and weave 17.

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Hi BillyT,

I think there is a lot of confusion, in general, about what a reference frame is. There is this comment by MacM as well as the discussion about directions on the Length Contraction thread.

-Dale

The scenario happened in all reference frames, of course. The preferred frame of reference is the rest frame of the nearest gravitating object, the Earth's surface. The frame of the clay pigeon launcher is the preferred frame of reference to describe the 'event'.

2inquisitive said:
...The frame of the clay pigeon launcher is the preferred frame of reference to describe the 'event'.
Ok, I will record your answer as Vh =50mph & Vv = O WRT resting brick. I.e. the the horizontal speed, Vh, of the launcher continues to be 50mph and the vertical speed, Vv, of it continues on this "flat land" to be zero. But it was a two part question. Why is this the ONLY frame in which the smashing event occurs? (This is more fun than I thought it would be.)

To Dale:
I do not understand why. A reference frame is ANY coordinate system in which at least three non-co-linear, point objects are stationary. (Have constant coordinates in the reference frame coordinate system. Two would do if you do not spin about the line passing thru them.) - Just made this one sentence definition up quickly, so it may need some changes, but seems ok NOW.

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Billy T said:
Here you seem to be trying for duck and weave 17. (Are you never satisfied with your already untouchable record of 16?)

Well I would certainly disagree that there have been any "Duck and Weaving" by me but some by others.

But clearly you are distorting as you normally do cnsidering I have had but one unchanging position from the outset. I may have found it necessary to re-pacakage the answer in different forms in an effort to crack through some thick skulls but the underlying principles have remainded constant.

It was bad enough when photons only belong to only one frame, but now Events only occur in one frame also?

And just what did yo not understand about the fact that with different photons (particularily with the red and blue filters) where the event was caused in one frame but not the other meant? Must every detail be spelled out for you?

Man and a "clay pigeon launcher"

While you do love to attempt to create complex distractions you fail because it is really always a simple matter. The event can only occur in the rest frame of the object in its local proper time. Now this needs just a touch of qualification. It is certainly possible, indeed necessary, to recognize that events occur to not only inertial moving objects but accelerating objects.

In that respect it is understoood that the moment of impact (or event) coincides with an instant in time where the object has what can be considered an a constant velocity and for events which are protracted they are actually a series of inertial events.

Billy T said:
Ok, I will record your answer as Vh =50mph & Vv = O I.e. the the horizontal speed, Vh, of the launcher continues to be 50mph and the vertical speed, Vv, of it continues on this "flat land" to be zero. But it was a two part question. Why is this the ONLY frame in which the smashing event occurs. (This is more fun than I thought it would be.)

Read my post again, Billy T. Do not put words in my mouth that I did not say. That is dishonest. NOWHERE did I state the the pigeon launcher frame was 'the ONLY frame in which the smashing event occurs'.

2inquisitive said:
The preferred frame of reference is the rest frame of the nearest gravitating object, the Earth's surface. The frame of the clay pigeon launcher is the preferred frame of reference to describe the 'event'.
What do you mean by "preferred frame of reference"? Do you mean that is the frame of reference that you personally prefer, or do you have some more fundamental meaning in mind?

-Dale

2inquisitive said:
Read my post again, Billy T. Do not put words in my mouth that I did not say. That is dishonest. NOWHERE did I state the the pigeon launcher frame was 'the ONLY frame in which the smashing event occurs'.
Sorry - I thought you were answering the question I asked as to which frame was the one in which the event occured. I take it how that your were not answering my question to MacM; (which he did not answer in his reply either.); but only makinf a comment that your would prefer to describe what traspired for the POV of the man (or the launcher, or the train as these three are in the same frame.) Honestly, I diD not mean to put words in your mouth, I now assume you were not in agreement with MacM, but like me, thing the smashing event OCCURS in all frames. Correct me if I am again putting words in your mouth.

To MacM:
I will get to your non-response soon as I can, but an apology comes first.

Sorry, Billy T, I did not memorize your scenario correctly either when I made the statement about the preferred frame. I was thinking the clay pigeon launcher was stationary on the Earth's surface, and the man with the rifle was on a moving train. My mistake.

MacM said:
Well I would certainly disagree that there have been any "Duck and Weaving" by me but some by others.
I guess we need a definition for "Duck and Weave." I will offer the following, but am sure I need not tell you to feel free to suggest your own or modify mine.

One is Ducking and Weaving, if they make a relpy that:
(1)Introduces some topic not part of the original discussion,
AND
(2)Does not discuss the physics of the original discussion.

Using the thought experiment of this thread as an example, and noting that I made only the assumption that the speed of light in any one frame is independent of direction of propagation, and even noted that it could be 10^4m/s in the embankment frame and 3x10^8m/s in the train and stating that SRT was obviously not assumed, you strongly earned one of your D&W badges by arguing that I was wrong because you have "already shown that SRT is wrong" (I almost gave you two D&W credits for that one.)

Second example: You state that I am claiming / implying that the explosions occur in one frame and not in the other because the photons “are different” in the two frames. (Something about photon energies, red and blue shifts, filters etc. when clearly I have stated that every photon is in every frame, until the photon ceases to exist, by being absorbed in some matter. (If that matter is one of the photo triggers of the firecrackers that absorption is significant to the thought experiment, but most of the millions of photons that come from the flash bulb just hit the side of the train or some rocks and dirt along the tracks to die without any significance for the thought experiment. No frame has any special claim on any of them, at least not after they have left the flash bulb. A lucky few will get to die in the sun or moon, depending on the time of day (and absence of clouds, of course).
MacM said:
And just what did you not understand about the fact that with different photons (particularily with the red and blue filters) where the event was caused in one frame but not the other meant? Must every detail be spelled out for you?
I need these details several times, I think, as you must show me why & how the photons "in" the train frame differ from the photons "in" the embankment frame. They are all just streaming away from the flash bulb until they hit something and die. BTW, I think, unless you have recently switched horses again, you even agree that in all frames the photons have the same speed, "c" = roughly 3x10^8m/s.
MacM said:
While you do love to attempt to create complex distractions you fail because it is really always a simple matter.
because you love to say silly thing like next sentence:
MacM said:
The event can only occur in the rest frame of the object in its local proper time.
It is nice to know that bullets can not cause “death events” unless they come to rest in you. (or you enter their rest frame, but perhaps that is too much of a “relativistic way” of looking at it for you?)

MacM said:
Now this needs just a touch of qualification. It is certainly possible, indeed necessary, to recognize that events occur to not only inertial moving objects but accelerating objects.
That is kind of you, but I only talk about inertial frames and objecs moving in them as I can not do the math of GR and only with it can GR be understood, so I do not understand GR. (I am not as much of a "physics outcast" as you, of course, but I do like my "relativistic mass" from time to time, especially if I mentally get near cyclotrons, which I understand well, but only with it. Hell, if the GR guys can go warping space itself, I should be allow to have my relativistic mass a function of direction in good old 3D space.)

Thus, please ignore all accelerating frames at the "smashing event" instant. I.e. Just tell me the inertial frame (wrt to the brick) in which at that instant, the "smashing event" is at rest, or "occurs" instead of merely being "observed" as it is in all other frames by your latest candidate for D&W17. Don't forget to tell why this unique inertial frame was chosen.

You may of course, refuse to answer. - Refuse to give Vh & Vv wrt to the brick for this unique frame as you have Ignored many questions in the past, but then you only get your "I-score" notched up one, but it is already so high I have lost count. Only when you make clear specifically what you are saying with "event is in" (or "occurs in") ONLY one frame will I give you credit for D&W17.

I am sure you want me to hold anyone foolish enough to try to top your record to this same high standard. - Namely: Simple incomprehensible gibberish never gets D&W credit. Only clearly stated nonsense gets D&W credit.

You have not been given D&W17 because you have not yet made it clear, even in the example test case (man, launcher, clay pigeon, train, etc.), what frame you claim the event actually “occurs in” to the exclusion of all others, (sort like a marriage contract, I guess). I.e. Your statements are still in the “incomprehensible gibberish” class, until you can at least give Vh and Vv of the “smashing event” frame for this clarification test case. Good luck - you can do it.

For example, Not only is the following “incomprehensible gibberish” but it appears to be speaking about the time of the "smashing event" instead of addressing the question as to which unique frame the "smashing event" is "in" rather than only "observed." Come on MacM, you can get it clear and answer the question with clear nonsense, I know you can if you try.
MacM said:
In that respect it is understoood that the moment of impact (or event) coincides with an instant in time where the object has what can be considered an a constant velocity and for events which are protracted they are actually a series of inertial events.

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2inquisitive said:
Sorry, Billy T, I did not memorize your scenario correctly either when I made the statement about the preferred frame. I was thinking the clay pigeon launcher was stationary on the Earth's surface, and the man with the rifle was on a moving train. My mistake.
No problem. You can vote again if you wish to support any particular frame as the one in which the "smashing event" occurs. (We do not dip fingers in ink here.)