Is Relativity Really Wrong? Exploring the Evidence on Motion and Perception

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In summary, the conversation discusses a website that claims to refute the principles of relativity through a thought experiment involving astronauts and synchronized clocks. However, it is pointed out that the experiment does not consider moving clocks and does not provide any real evidence to refute relativity. The conversation also highlights the importance of conducting real experiments rather than relying on logic or thought experiments to refute a scientific theory.
  • #71
geistkiesel said:
Now you're dodging bullets. Are yousaying that the use of the word "null" is ambiguous? I claimed the experimentors, Michelson-Morley found a wave length shift 1/20 of what the predicited shift would be for the Earth moving through the aether. Why are you so obstinently trying to confuse the issue.
Its ambiguous because you are trying so hard to make it ambiguous. Just averaging all the results and coming up with 1/20 of predicted doesn't even give you half of what you need to interpret the results. At the very least, you need the standard deviation: if its 1/20 +- 1/10, then that means the experiment found nothing at all.
 
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  • #72
DrChinese said:
We need to agree on a base starting point. You say (at the referenced link):

"Any theory purporting to alter, or negate, or change by a ‘perception’ rational, the simultaneous measurements of the events are to infect natural physical law by an irrational corruption constituting scientific fraud. Anyone believing in the postulates and implications of relativity theory has negated their rational thinking processes. Physical law, though corrupted by mathematical abstractions veiled as legitimate descriptions of physical processes, is eternal – theories come and go, their ignorant predictions exposed by the gusting aethereal wind. "

Talk about hot air, and saying nothing. Let's agree or disagree on something specific: SR states that all observers will measure the speed of light to be c. Agree or disagree that this prediction of "irrational" SR is in fact born out in experiments? It's a simple question, can you please answer it? If the answer is disagree, can you please state under what specific circumstances a test of the speed of light yields a value different than c?



OK let you and I start over OK? I've been obnoxious, a state that comes and goes depending on the heat of the situation.

I agree that SR says all observers will measure c as the speed of light.I cannot agree unambiguously that all measurements support this finding. I mention the Michelson-Morley experiments, followed by Dayton Miller's experiments, and "not shown": by the famous "eclipse experiments" fllowing WWI. I know you may make reference other experiments claimed to substantiate the postulates oF SR. This is not the debate in directly front of us. We focus first on AE's derivation of the consequences of SR, which according to AE as stated clearly in his book "Relativity" lead to the conclusion that events simultaneous in one frame of reference are not simultaneous in another. This and only this is the focus my effort hee in these postings.

Perhaps if I amend the above that you quote to link the, " . . . believing in the postulates etc . . " to the preceding sentence, that this would take some sting from the inferences.

The link I refer to, http://frontiernet.net/~geistkiesel/index_files/

If the simultaneity consequences are indeed flawed, totally that is, and the derivation of these consequences are a necessary conclusion, or implication of SR, or follows logically from SR, then SR is flawed by the reasonong that SR generated a faulty "loss of simultaneity consequence".

Whether the reality of the experiments you refer to, and even mine MM, Dayton Miller etc. are asserted as the "only" truth of the physical matter then there nothing I can do about that, except to say, that by the indirect means of 'the proof' that the simultaneity consequences of SR are faulty as proved in the link, then other than an SR rational must be used to explain the 'apparent measurenment of the speed of light being c'. The 'c' is not proved or disproved by holding up our respective lists of experimental evidence, the 'c' is proved or not by the conclusion of the analysis in the link.

It seems to be a difficult situation to communicate, but I see in the literature that the loss of simultaneity consequences is invariably disguised in the rhetoric of "what the observer in X frame observes, or perceives " as if only the observer's perception is under discussion rather than the physics of the matter. I see a huge gap in the language and therefore the conclusions drawn from those echoing AE's simultaneity consequences.

Simply said, I read "perceptions of the human observer' is equated with 'physical law' in the sense that a hallucination may be claimed equated with physical law.

A simultaneous event once concluded cannot be altered by perception or theory, do you not agree?
 
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  • #73
According to the book "Laser Propulsion" produced by Unitel NW Inc.,
www.unitel-aerospace.com[/URL], a prime government contracting Aerospace
R&D Firm, the rate at which time passes in hyperspace compared to
Minkowski space, the space we live in, can be a ratio of 70 hours in
hyperspace to 253 years in Minkowski space(real space). Time in
hyperspace is measured in imaginary units, and 1 imaginary second in
hyperspace-time corresponds to 31,682.82857142857 seconds in real
space-time. According to Lorents transformations, the rate at which
the spiral(in previous post) edge travels through time, is
-0.0009738928534425216 imaginary seconds back in time, for every
second of transmission by the large number of 100GHz transmitters
around the circumference of the 1 ft diameter metal waveguide disc.
This translates into -30.855680322558822 seconds in reals space-time
for every second of transmission by the large number of 100GHz
transmitters around the circumference of the 1 ft diameter metal
waveguide disc with reciever in the disc's center. What do you think?
Want to take a ride?

Inquisitively,

Edwin G. Schasteen
 
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  • #74
DrChinese said:
How about discussing something the rest of us agree means something. As has been stated previously, Einstein's comments are merely a general discussion of the theory and you are not actually attacking the formalism of SR with your statements.

You are correct. I am attacking only the formalism of the consequences flowing from SR that conclude that events simultaneous in one frame are not simultaneous in another. In the link the situations of 'simultaneous' are clearly defined. In the stationary frame two lights are pulsed on at the same instant. In this and other threads on the subject (see "Why Relativity is Wrong" in the "Relativity Forum where myself and Doc Al go at it head to head especially the concluding posts) I have strived to be consistent.

DrChinese said:
If you can convince yourself you can measure or define events as being simultaneous, that is fine with me. As a practical matter, we find this necessary frequently. As far as I know, there is nothing in SR that actually addresses this. But I don't think you can demonstrate that all observers will judge events spatially separated as simultaneous without making assumptions that render the conclusion meaningless. For instance - is simultaneous defined as occurring at the same absolute time? Or is it occurring at an agreed upon difference in times from "now"? I.E. My definition of simultaneous may well be quite different than yours.

I mean it like the link defines it. Said another way two simultaneously exploding supernovae, in a the stationary frame, each erruption on the opposite sides of the universe, are simultaneous to all frames whether any observer is aware of the event or not.

I amm saying that physical events are not perception defined. The events occur and perhaps an observer makes measurments inclding some time analysis of "when " the event occurred and how it occured, but the physical event is not functionally related to any human perception as a parameter of the event.

DrChinese said:
P.S. You need a new book too, p. 25-27 of your "Relativity" book must be totally worn out by now.

Are you suggesting that time has altered the perceptions of Professor Einstein? You are going to have to start that that thread.
Also, see my response to your other most recent post addressed to myself.
 
  • #75
Doc Al said:
Nope, that's the same tired, incoherent, circular argument as always.

I suggest reading it one more time. What Einstein does is start with stationary observers seeing two simultaneous events. Then, using the postulates of relativity, he deduces that moving observers must disagree. Unlike you, he doesn't just assume that simultaneity is observer-independent.

I do not start with that assumption. I start with the observer questioning whether the reception of the pulsed lights came from a simultaneous event, or if the pulses were emitted at different times.


Not only can the moving observers measure their relative motion, they can also decide for themselves when they detect the pulses.


Doc Al said:
There you go again, simply assuming what you should be demonstrating!


Just repeating your mantra "the events occurred at the same instant" doesn't make it so. Since the events in question are not collocated, what makes you think they are simultaneous? A consistent way of tracking time would help. (On this planet, we have clocks.)

I advise you to get serious. Unless you tell the moving observer when to starting counting, your statement is meaningless. Now, what could be agreed upon, without any fancy clocks or synchronization, is that two observers can choose to set their clocks to zero at the precise instant that they pass each other. Too unambiguous for you?
Interesting... both observers measure the time of two events... but they don't use clocks! Simply brilliant! :smile:

The events of the pulses being simultaneous int he stationary frame is a given condition of the hypothetical. When the moving observer passes the midpoint he starts his clock at zero, as does the stationary observer. Likewise, I've added recording gear along the path of the moving platform that detects the lights from both sources simultaneous with the recording on the moving platform. No clocks are needed here to define simultaneous.

If you and I bump into each other in the street, do we need clocks to determine that the 'bump' was simultabeous for both of us?

Doc Al said:
Same instant as what? I think we're getting at the root of your confusion. Just because the pulses are detected by both stationary and moving observers at the same time (since they are collocated) does not mean that the two observers measure the same time! (Unless you have them reset their clocks with each measurement! :smile: )

I responded in another post that with the simultaneous measurement of the arrival of the llight from A and B, each observer passes their 'clock time' to the other. This might be interesting for some purposes but is irrelevant here.

Doc Al said:
I just call it an illustration of your serious misunderstanding of what simultaneity means. No one disputes that collocated measurements (space-time coincidences) are simultaneous! It's the non-collocated ones that are of interest.


Again, no one disputes that collocated measurements (space-time coincidences) are simultaneous! It's the non-collocated ones that are of interest. You've missed the entire point.

Well, the measurements of Einstein example weren'y collocated until I laid down some measuring gear in the middle of the night. But what can this possibley have to do with whether the pulses are simultaneous in another frame or not?

Doc Al said:
Does the pulse for event t1 arrive at the collocated stationary and moving observers simultaneously? Yes! (It's a space-time coincidence.) Do the two observers agree on the time it arrives on their clocks? Of course not!

So what if their clocks disagree?Or if the observers agree. The agreement is totally irrelevant tot he simultaneity question. If one clock measues 10, the other 9 the times are equivalent regardless of what the clocks say. And the clocks and observers have no input into the physics of the event. They observers are just trying to ferret out the sequence of events.

Doc Al said:
Of course clocks matter! That is, if you care to compare one event (t1, say) with another (t2, say). If you want to make a statement about whether an observer measures two non-collocated events (that is, events occurring at different points in space-time) to be at the same time, you must compare clock readings, or equivalently, create some signalling scheme. (Based upon real physics, of course.)

The moving observer can determine for himself if the lights pulsed on simultaneously in his frame.

You can solve the problem as you see fit. I say the moving observer, using his own clocks, his own t1 and t2 and velocity wrt stationary frame can determine if the lights were pulsed on simultaneously in the moving frame. The speed of light is consistently c in his frame I will grant you.http://frontiernet.net/~geistkiesel/index_files/ Apparently it is beyond your reach, or willingness to understand.

Tkae this hypothetical: A return to an earlier problkem where a moving platform arrives at the midpoit of two pulsed light measured in the stationary frame. As I remember you insisted he moving obe=server would always see the pulses as no occurring at the same time in his frame. Let uis add a mirrored twin of the moving observer you insisted would not see the pulses as simultaneous coming at you observer from the B light pulse side. Do each of the observers determine the pulses to be at different times? If so then each determines that differenmt lights were pulsed on first, right? Who wins?

Or are we merely talking about the "perceptions" of the observers?

Add a third moving observer approacj=hing the midpoint on he plane perpendicular topt he appraoching wave fronts passing through the stationary midpoiint. All three observers are equidistant from the midpoint in the stationary frame at all times. Which light gets pulsed on first for which observer? By the time they figure this one out the light pulses and the three observers will all have met simultaneously at the midpoint giving final, if not ahorrible resolution to the ultimate event question of this problem.
 
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  • #76
DrChinese said:
But I don't think you can demonstrate that all observers will judge events spatially separated as simultaneous without making assumptions that render the conclusion meaningless. For instance - is simultaneous defined as occurring at the same absolute time? Or is it occurring at an agreed upon difference in times from "now"? I.E. My definition of simultaneous may well be quite different than yours.

I can see that you are truly making an effort to get to the essence of this, which I appreciate moe than what shows. I've responded to this post already, but see that this addendum might be helpful.

If a stationary observer determines an event to be simultaneous, where the event is the occurance of two single events such as our pulsing light sources, then all frames should also determine the same.

1st, I point to your statement " . . .that all observers will judge events . . . " and ask the all too simple question: Are the physics of events observer dependent? No, I say, the events, such as simultaneous or nonsimultaneous events need no observer input to give the event "completion" or "closure" . Only when we make an attempt to understand the sequence of events, for instance do obsevers require some information in order to come to a conclusion.

If events in stationary and moving frames were universally simultaneous then the observer making a conklusin to the contrary would be in error. If events simultaneous in one and not simultaneous in another was a univesally accurate statement observers could still not alter the reality. I am asking you to ask yourself, are we discussing 'the observer' here as a participant in the physical process of simultaneity of events? A quick draw denial of this might obscure a reality that this is indeed what we are discussing. From my pespective the language used by those in opposition to the offered thesis seems to infer be just that, especially that language of Doc Al.

What assumptions could I make that would make the conclusion meaningless?
I haven't denied the postulate regarding the constancy of the measurement of c as the speed of light, even though I may have some personal reservations about the claim. I have, without expressly stating the matter, that the physics in all inertial frames will provide the same answer. Using this the time of fliight of wave fronts to arrive at the midpoint of the moving wave fronts is the same for each wave front. I also made the observation that once two wave fronts are existing in the universe the midpoint of the wave fronts is invariant, spatially. This sounds very much like an 'absolute location in space, and if it is does it get discarded by a theory that denies the reality? Are midpoints of colliding wave fronts invariant? It seems to me that if they were not then the velocity of one or both the wave fronts would have to vary, otherwise how would you accout for a drifting midpoint?.

Are the events simultaneously ocuring in the same absolute time? Perform a gedunken with me. Two exploding supenovae located on opposite sides of the universe erupt simultaneously in a stationary frame. Does the fact that we cannot measure any aspect of the eruption have any bearing on the simultaneity of the event? Does out ignorance negate the simultaneous nature of the event? Would this be an example of 'absolute time'?

We do not have to "agree" on anything to conclude the operation of an event.Our pereptions may require some language that eleminates ambiguity, but this is only fr our convenience. Is there anything ambiguous about the statement at the same time in a stationary frame, event though we both would be hard pressed to find such an entity. We use the everyday language that a stationary observer wrt to any identifiable spot on the planet sufficiently defines a 'stationary observer' though I expect Doc Al or somene else will glom onto this as "see, there is no such thing as a stationaruy observer". However, in the train and stationary platform problems under discussion there is no intrinsic ambiguity in recognizing the complex motion of the surface of the planet at all times.

If you see an ambiguity if defining "at the same time" then show it, but the mere speculatuion of the mere possibility that we could be ambiguous doesn't substitute for an actual ambiguity.
 
  • #77
geistkiesel said:
OK let you and I start over OK? I've been obnoxious, a state that comes and goes depending on the heat of the situation.

I agree that SR says all observers will measure c as the speed of light.I cannot agree unambiguously that all measurements support this finding. I mention the Michelson-Morley experiments, followed by Dayton Miller's experiments, and "not shown": by the famous "eclipse experiments" fllowing WWI. I know you may make reference other experiments claimed to substantiate the postulates oF SR. This is not the debate in directly front of us. We focus first on AE's derivation of the consequences of SR, which according to AE as stated clearly in his book "Relativity" lead to the conclusion that events simultaneous in one frame of reference are not simultaneous in another. This and only this is the focus my effort hee in these postings.

Perhaps if I amend the above that you quote to link the, " . . . believing in the postulates etc . . " to the preceding sentence, that this would take some sting from the inferences.

The link I refer to, http://frontiernet.net/~geistkiesel/index_files/

If the simultaneity consequences are indeed flawed, totally that is, and the derivation of these consequences are a necessary conclusion, or implication of SR, or follows logically from SR, then SR is flawed by the reasonong that SR generated a faulty "loss of simultaneity consequence".

Whether the reality of the experiments you refer to, and even mine MM, Dayton Miller etc. are asserted as the "only" truth of the physical matter then there nothing I can do about that, except to say, that by the indirect means of 'the proof' that the simultaneity consequences of SR are faulty as proved in the link, then other than an SR rational must be used to explain the 'apparent measurenment of the speed of light being c'. The 'c' is not proved or disproved by holding up our respective lists of experimental evidence, the 'c' is proved or not by the conclusion of the analysis in the link.

It seems to be a difficult situation to communicate, but I see in the literature that the loss of simultaneity consequences is invariably disguised in the rhetoric of "what the observer in X frame observes, or perceives " as if only the observer's perception is under discussion rather than the physics of the matter. I see a huge gap in the language and therefore the conclusions drawn from those echoing AE's simultaneity consequences.

Simply said, I read "perceptions of the human observer' is equated with 'physical law' in the sense that a hallucination may be claimed equated with physical law.

A simultaneous event once concluded cannot be altered by perception or theory, do you not agree?

Thank you. Even if you are right and AE is wrong, there is no reason not to discuss these matters without calling other scientists names.

Second, I seriously have a problem with the term simultaneous. Everyone thinks the same thing when we are discussing events on Earth which are easily synchronized.

But your example of the exploding supernovae is problematic to me.

a) Is there a clock that we all agree upon? One which we have somehow synchronized for all observers?
b) What about distances? Do we all agree upon the locations of the events we call simultaneous? And if so, how do we agree without measuring elapsed time using the same clocks mentioned in a).
c) In other words, I fear that we cannot, in fact, develop a good definition of simultaneous without reference to absolute time and space. And therefore, we must assume something which should not be assumed.

In other words, a reasonable observer concludes that an event seen locally at time T2 which occurred at a point D1 distance away must have occurred at "absolute" time T1 - found classically by T1=T2-(D1/c) - for purposes or determining whether it is simultaneous with another event.

However, now relativity comes into play, due to the relative velocity of the observers. In fact, the above classical formula violates SR. Further, SR claims there is no preferred reference frame. Therefore it is not possible to get all observers to agree on the sequence of events. As I understand your position, there is in fact a way to adjust the calculations so all observers agree.

Do I state your position correctly? In other words, space-like separated observers can rationally communicate so that positions and velocities can be agreed upon.
 
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  • #78
DrChinese said:
Thank you. Even if you are right and AE is wrong, there is no reason not to discuss these matters without calling other scientists names.

Second, I seriously have a problem with the term simultaneous. Everyone thinks the same thing when we are discussing events on Earth which are easily synchronized.

But your example of the exploding supernovae is problematic to me.

a) Is there a clock that we all agree upon? One which we have somehow synchronized for all observers?

I mean simultaneous conceptually, like this: right at this instant two supernovae erupt. Period. The eruptions are simultaneous. We don't need clocks to grasp the simultaneous nature of the eruption. We do need measuring devices to determine arrival times of light waves and particles and any other measurement of physically measurable entities to back analyze, to determine when and if some event occurred and even if the event was simultaneous, but to assume at the get go that simultaneous events in stationary platforms are not simultaneous in a moving platform is theoretically premature and physically not justified.

We must distinguish between a physically simultaneous event, the supernovae and measuring the event as simultaneous. I have assumed throughout that the postulates of relativity that lead to the determiination of the theoretical construct that what is simultaneous in one frame, the supernovae, is not simultaneous in another is not necessarily a construct defining a physical event, or process, rather it is a construct that purports to define mesurements of data related to the event under scrutiny and the implications of that data however acquired and anlyzed using the current theoretical constructs. All of this done not to determine the physical nature of yhe event but to determine a perception of the event. The difference in the two cases is not a subtle one.

Let us assume that everyone agrees that it is the measurements that are under examination, not the event itself. Okay, the postulates of SR determine that our measurements will conclude that under certain circumstances (measured from moving frames for instance) the event was not simultaneous and hence we then make the next logical assignment that the event itself was not simultaneous, and that it is not just the perceptions of the event that are the end point of all the analytic effort. This is how I see the postulates operating as I have been discussing them. We are not interested in organizing our perceptions of the events, we want to know whether the event was simultaneous, and to hell with whatever our mere perceptions happen to be.
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DrChinese said:
b) What about distances? Do we all agree upon the locations of the events we call simultaneous? And if so, how do we agree without measuring elapsed time using the same clocks mentioned in a).

I think you may have asked a question not relevant if we are focusing on the issue of simultaneity of events. I on exmple in my link I have strewn along the path of the moving frame some measuring gear that does what the gear on the platform does. the detection of light pulses in both frames are simultabneous, conceptually, measuring the since the platform passed the "midpoint" will show up differently on a system where clocks dilate in moving frames. Let's us say that ten years after the platform passes through the midpoint and both clocks are zeroed and the pulses aer detected simultaneously at frame nmeasured times and that neither knows of the others presence or the fact that measurements were made. The observers meet and in the discussion they both conclude that they are talking about the same set of events. The observers notice times increments between measurments are different but a video camera catches them making their obsevation simultaneously. They correlate the data and conclude that the event was simultanous in both frames using the simpleminded technique in the 'link'. However, the moving platform observer does not need the information provided by the stationary observer as he can determine for himslef whether the event was simultanous from, 1) his measured velocity passing the midpoint, 2) the delta time from the midpoint to the instants of measuring the two pulses, one from the front, the other from the rear and 3) the speed of light being c. See the link on how he does this.

DrChinese said:
c) In other words, I fear that we cannot, in fact, develop a good definition of simultaneous without reference to absolute time and space. And therefore, we must assume something which should not be assumed.

In other words, a reasonable observer concludes that an event seen locally at time T2 which occurred at a point D1 distance away must have occurred at "absolute" time T1 - found classically by T1=T2-(D1/c) - for purposes or determining whether it is simultaneous with another event.

However, now relativity comes into play, due to the relative velocity of the observers. In fact, the above classical formula violates SR. Further, SR claims there is no preferred reference frame. Therefore it is not possible to get all observers to agree on the sequence of events. As I understand your position, there is in fact a way to adjust the calculations so all observers agree.

Reference to absolute space and time: For the case of two moving wave fronts existing in the universe, do you agree that all observers in all platforms will determine the location of one and only one midpoint of those expanding EM spheres? and that everyone will determine the exact same location of that midpoint? The midpoint cannot drift unless the wave fronts drift, which would mean that the wave front velocity is variant,which would mean tha 'c' varies. Do you want to do this?

There can be only one collision of the wave fronts at the same place and time, universally.

I conclude for the purposes of this duiscussion that we have found a satisfactory absolute space.

Regardless of clock rates in all the possible moving frames, each will predict the exact moment the expanding EM spheres collide at the absolutely only place in the sum totality of the universe where they could collide, and each will predict the same absolute instant when those wave fronts meet, what ever natural and influence their clocks happen to be subject to, assuming of course they make the correct assumptions about their clock rates. This latter condition is a technology issue, not an issue in the physics of the problem.

DrChinese]Do I state your position correctly? In other words, space-like separated observers can rationally communicate so that positions and velocities can be agreed upon.

Within the limits if the current technology of the itime frame under consideration, yes. There are only the obvious physical limitations to their comparing positions and velocties. Space-like separated observers may do what you say, but the communiation isn't necessary to determine the simultaneity of events in the sense that such communication is absolutely necessary to determine whether an event was simultaneous in the interested observer's frame of reference. Any observer-observer communications would function as a calibration of equipment, or a test of additional parameters in the methods used to perform the analysis, meaning as a check on the integrity of any 'theory development' processes, which is the defined limiting purpose of this forum is it not?
 
  • #79
fbsthreads said:
do you get money every time someone clicks that link, because you've posted it many times in this thread.

Talk to the administration for mailing instructions if you want to send money. I am involved in in serious personal war agansit poverty. Do you find the reference obsjectionable? Are your sensibilities piqued? have you been insulted?
Just what is your problem? Does it have anything to do with physics, or are have I just truned you against myself by my nature, my way, my doing things the way I want to do them, the way I choose to do them, the way your mother told you not to do them? Go do something to yourself . . .
 
  • #80
geistkiesel's error II

geistkiesel said:
I do not start with that assumption. I start with the observer questioning whether the reception of the pulsed lights came from a simultaneous event, or if the pulses were emitted at different times.
You explicitly declare that the pulses are emitted simultaneously for all observers--as if that is some physical law you are invoking.
Not only can the moving observers measure their relative motion, they can also decide for themselves when they detect the pulses.
Absolutely!
The events of the pulses being simultaneous int he stationary frame is a given condition of the hypothetical.
Agreed.
When the moving observer passes the midpoint he starts his clock at zero, as does the stationary observer.
This is ambiguous. Allow me to restate it: At the precise moment that the moving observer passes by the midpoint he asks the stationary observer posted there "What does your clock read?". The moving observer then sets his clock to match. No problem there.
Likewise, I've added recording gear along the path of the moving platform that detects the lights from both sources simultaneous with the recording on the moving platform. No clocks are needed here to define simultaneous.

If you and I bump into each other in the street, do we need clocks to determine that the 'bump' was simultabeous for both of us?
That "bump" is a single event. Both observers (you and I) can measure the time that the event occured. We, of course, may get different answers, since we are moving with respect to each other. But, and this is key, this is not an example of simultaneity! Simultaneity refers to the time order of two events (or more) as measured by a single observer (or his frame).
So what if their clocks disagree?Or if the observers agree. The agreement is totally irrelevant tot he simultaneity question. If one clock measues 10, the other 9 the times are equivalent regardless of what the clocks say. And the clocks and observers have no input into the physics of the event. They observers are just trying to ferret out the sequence of events.
Again, you are treating clock readings as if they were just an artifact of human perception. Not so! The time measured by the clocks is real, physical time. If your clock says an hour passed then you are really an hour older. This is not an illusion. (You could have spent that hour roasting a chicken or watching reruns of your favorite sit-com.)

If two observers in relative motion observe two events, then each will record the time of the event according to their own clocks. This is real physics! To meaningfully say that these events are simultaneous (or not) requires you to define which reference frame is making the measurements. (And also how the various observers in that frame have synchronized their clocks.)
The moving observer can determine for himself if the lights pulsed on simultaneously in his frame.
Yes, you say that, but you don't mean it! :smile: When his clocks and real physics say they were not pulsed at the same time, you just brush those inconvenient facts aside, attributing them to some error in perception.

Tkae this hypothetical: A return to an earlier problkem where a moving platform arrives at the midpoit of two pulsed light measured in the stationary frame. As I remember you insisted he moving obe=server would always see the pulses as no occurring at the same time in his frame. Let uis add a mirrored twin of the moving observer you insisted would not see the pulses as simultaneous coming at you observer from the B light pulse side. Do each of the observers determine the pulses to be at different times? If so then each determines that differenmt lights were pulsed on first, right? Who wins?
Again you assume that simultaneity is some objective fact independent of who makes the observations. The answer is: No one wins! Simultaneity is relative to the observing frame. That's the point.
 
  • #81
geistkiesel said:
I mean simultaneous conceptually, like this: right at this instant two supernovae erupt. Period. The eruptions are simultaneous. We don't need clocks to grasp the simultaneous nature of the eruption. We do need measuring devices to determine arrival times of light waves and particles and any other measurement of physically measurable entities to back analyze, to determine when and if some event occurred and even if the event was simultaneous, but to assume at the get go that simultaneous events in stationary platforms are not simultaneous in a moving platform is theoretically premature and physically not justified.

We must distinguish between a physically simultaneous event, the supernovae and measuring the event as simultaneous. I have assumed throughout that the postulates of relativity that lead to the determiination of the theoretical construct that what is simultaneous in one frame, the supernovae, is not simultaneous in another is not necessarily a construct defining a physical event, or process, rather it is a construct that purports to define mesurements of data related to the event under scrutiny and the implications of that data however acquired and anlyzed using the current theoretical constructs. All of this done not to determine the physical nature of yhe event but to determine a perception of the event. The difference in the two cases is not a subtle one.

Let us assume that everyone agrees that it is the measurements that are under examination, not the event itself. Okay, the postulates of SR determine that our measurements will conclude that under certain circumstances (measured from moving frames for instance) the event was not simultaneous and hence we then make the next logical assignment that the event itself was not simultaneous, and that it is not just the perceptions of the event that are the end point of all the analytic effort. This is how I see the postulates operating as I have been discussing them. We are not interested in organizing our perceptions of the events, we want to know whether the event was simultaneous, and to hell with whatever our mere perceptions happen to be.

Here is the first point of departure for us. I agree there is a difference between the observation of 2 space-like separated events and the events themselves. I.e. what you call the physical event and the perception of the event. You clearly place the physical event above the perception of the event, while I tend to see it the other way around.

In other words, "all we know is the results of experiments". That is the base point of SR - and of QM as well. Instead of trying to assert the physical existence of something which many consider to be in doubt, consider the measurement/observation/perception as fundamental and describe that.

So from my perspective, the question is the observation of 2 events. What is simultaneous is the receipt of photons of light from the distant sources. Clearly, that does not make the physical events simultaneous in any sense.

Now, suppose, we have 2 observers, moving with respect to each other. Their paths intersect at precisely the moment that photons from 2 supernovae arrrive. In my opinion, SR predicts that both observers will acknowledge the simultaneous observation of the supernovae. Do you agree a) that SR predicts this, and b) that this "simultaneous observation" will be the result?
 
  • #82
geistkiesel said:
Reference to absolute space and time: For the case of two moving wave fronts existing in the universe, do you agree that all observers in all platforms will determine the location of one and only one midpoint of those expanding EM spheres? and that everyone will determine the exact same location of that midpoint? The midpoint cannot drift unless the wave fronts drift, which would mean that the wave front velocity is variant,which would mean tha 'c' varies. Do you want to do this?

There can be only one collision of the wave fronts at the same place and time, universally.

I conclude for the purposes of this duiscussion that we have found a satisfactory absolute space.

A. I don't see how any observer can draw any source position information from a photon received at a detection device. The most that can be determined is perhaps direction (i.e. it came from where the telescope is aimed) and perhaps relative velocity (i.e. between the source and observer, if there is a shift in the frequency of a known spectra line).

So, no, I do not agree that all observers will agree on the location of the midpoint of the 2 wave front sources. In fact, no one will have any clue as to the location of the midpoint from this information.

B. I am also not following your reference to the "midpoint of the 2 expanding EM spheres". I am not familiar with the analogy you are making, and how it relates to our examples. Are the spheres associated with the light from the 2 supernovae in your example? And how does the midpoint fit into this?

EDITED TO ADD to B.: I revisited a thread you started a few days ago, and I believe you are stating that the midpoint is where our observers are being positioned. So in your example, the supernovae are seen simultaneously by co-located observers equidistant to both. Is that correct?
 
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  • #83
DrChinese said:
A. I don't see how any observer can draw any source position information from a photon received at a detection device. The most that can be determined is perhaps direction (i.e. it came from where the telescope is aimed) and perhaps relative velocity (i.e. between the source and observer, if there is a shift in the frequency of a known spectra line).

So, no, I do not agree that all observers will agree on the location of the midpoint of the 2 wave front sources. In fact, no one will have any clue as to the location of the midpoint from this information.

B. I am also not following your reference to the "midpoint of the 2 expanding EM spheres". I am not familiar with the analogy you are making, and how it relates to our examples. Are the spheres associated with the light from the 2 supernovae in your example? And how does the midpoint fit into this?

EDITED TO ADD to B.: I revisited a thread you started a few days ago, and I believe you are stating that the midpoint is where our observers are being positioned. So in your example, the supernovae are seen simultaneously by co-located observers equidistant to both. Is that correct?

The statement regarding the midpoint of expanding EM spheres was intended to demonstrate the existenxcce of an absolute space. Only instances of situations where information of moving light sources is known etc would there be practical application. Whether human observers agree or not, two moving wave fronts have one and only one midpoint whether your observers detect it or not, whether your observers agree or not. Your obsession with satisfying observer's perceptions keeps you expansion potential at minimum. The light from my supernovae example went whizzing by. The supernovae located at opposite sides pf the universe exploded as you were reading the words. No human will ever detect the moving wave fronts and no human being will ever give a sou about the collision point. The point attempted to be made is that there is one anf only one midpoint of colliding EM spheres, be they supenovae or signal pulses from orbiting sattelites.

Relativity theory using any derivation of RT postulates that conclude in the simultaneity description that what is simultaneous in one framwe is not simultaneous in another is an error function. Einstein and any others who maintain the lost simultaneity scam are the ones that are lost.
 
  • #84
DrChinese said:
Here is the first point of departure for us. I agree there is a difference between the observation of 2 space-like separated events and the events themselves. I.e. what you call the physical event and the perception of the event. You clearly place the physical event above the perception of the event, while I tend to see it the other way around.

In other words, "all we know is the results of experiments". That is the base point of SR - and of QM as well. Instead of trying to assert the physical existence of something which many consider to be in doubt, consider the measurement/observation/perception as fundamental and describe that.

So from my perspective, the question is the observation of 2 events. What is simultaneous is the receipt of photons of light from the distant sources. Clearly, that does not make the physical events simultaneous in any sense.

Now, suppose, we have 2 observers, moving with respect to each other. Their paths intersect at precisely the moment that photons from 2 supernovae arrrive. In my opinion, SR predicts that both observers will acknowledge the simultaneous observation of the supernovae. Do you agree a) that SR predicts this, and b) that this "simultaneous observation" will be the result?

Before and after your two observer pulse detection, the third observer, who receives the light pulse from one, then the other source perceives what? That the light pulses weren't simultaneously emitted? Isn't this what SR predicts? If it does then SR is just another lying theoretical perception scammer..
 
  • #85
How does one tell if two events are simultaneous?
 
  • #86
Doc Al said:
You explicitly declare that the pulses are emitted simultaneously for all observers--as if that is some physical law you are invoking.

Absolutely!

Agreed.

This is ambiguous. Allow me to restate it: At the precise moment that the moving observer passes by the midpoint he asks the stationary observer posted there "What does your clock read?". The moving observer then sets his clock to match. No problem there.
That "bump" is a single event. Both observers (you and I) can measure the time that the event occured. We, of course, may get different answers, since we are moving with respect to each other. But, and this is key, this is not an example of simultaneity! Simultaneity refers to the time order of two events (or more) as measured by a single observer (or his frame).

Again, you are treating clock readings as if they were just an artifact of human perception. Not so! The time measured by the clocks is real, physical time. If your clock says an hour passed then you are really an hour older. This is not an illusion. (You could have spent that hour roasting a chicken or watching reruns of your favorite sit-com.)

If two observers in relative motion observe two events, then each will record the time of the event according to their own clocks. This is real physics! To meaningfully say that these events are simultaneous (or not) requires you to define which reference frame is making the measurements. (And also how the various observers in that frame have synchronized their clocks.)

Yes, you say that, but you don't mean it! :smile: When his clocks and real physics say they were not pulsed at the same time, you just brush those inconvenient facts aside, attributing them to some error in perception.


Again you assume that simultaneity is some objective fact independent of who makes the observations. The answer is: No one wins! Simultaneity is relative to the observing frame. That's the point.

You have proved my point. Yes simultaneity is an objective fact. You are saying the rea;ity is what the observer perceives. I say the reality is independent of what obsevers perceive. If the lights were pulsed on in a stationary frame simultaneously, then the approaching twins both determining a different light pulsed on first are both stating a law of physics truism. The third observer approaching the midpoibnt and arriving there wih the frist two observers has been on a plane perpendcular to the moving wave fronts so that the approaching wave fronts have always been equidistant from him detects what?

The world out there sir is real, and for you, it ain't what you think.
 
  • #87
Doc Al said:
This is ambiguous. Allow me to restate it: At the precise moment that the moving observer passes by the midpoint he asks the stationary observer posted there "What does your clock read?". The moving observer then sets his clock to match. No problem there.
That "bump" is a single event. Both observers (you and I) can measure the time that the event occured. We, of course, may get different answers, since we are moving with respect to each other. But, and this is key, this is not an example of simultaneity! Simultaneity refers to the time order of two events (or more) as measured by a single observer (or his frame).

You are correct. Our cousins (who I failed to mention) across the street bumped into each other the same instant we did in our mutual frames. Each of us were moving at different velicities, the bumps, however were simultaneous to all four, as referenced to the stationary street, likewiae to or bumping nephews around the corner who, we cannot see.

You may have difficulty seeing the physics of the matter, but any theoretical model used as an analytic tool in manipulating measurements, time etc. and coordinating perceptions is totally irrelevant to the truth of the physical event, a physical reality, other than a perception, other than the mere conclusion of measurers and thereticians. The moon exists along with Venus right now, simultaneously to where they are, and when they are, like now, now, now, now . . . . whether you perceive the reality of this or not.
 
  • #88
geistkiesel said:
The statement regarding the midpoint of expanding EM spheres was intended to demonstrate the existenxcce of an absolute space. Only instances of situations where information of moving light sources is known etc would there be practical application. Whether human observers agree or not, two moving wave fronts have one and only one midpoint whether your observers detect it or not, whether your observers agree or not. Your obsession with satisfying observer's perceptions keeps you expansion potential at minimum. The light from my supernovae example went whizzing by. The supernovae located at opposite sides pf the universe exploded as you were reading the words. No human will ever detect the moving wave fronts and no human being will ever give a sou about the collision point. The point attempted to be made is that there is one anf only one midpoint of colliding EM spheres, be they supenovae or signal pulses from orbiting sattelites.

Relativity theory using any derivation of RT postulates that conclude in the simultaneity description that what is simultaneous in one framwe is not simultaneous in another is an error function. Einstein and any others who maintain the lost simultaneity scam are the ones that are lost.

First of all. your statement about the "one and only one midpoint" of 2 expanding spheres is factually incorrect. Spacetime is curved (GR), and even in QM alone there is no such point. Even if it were true - which it is not - what would the significance be of such a point? I am still missing the entire line of reasoning related to this.

Second, you are making a logic error when you assume there is an absolute space and then use this to attempt to disprove SR (this tautology has been pointed out to you previously by others).

And third, my "obsession with observers" is firmly grounded in the philosophy of an objective science. So don't expect that I will see your criticism as such.

You didn't address it, so I assume you are now in agreement with my A. point: that an observer cannot determine the source point of photons detected.
 
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  • #89
geistkiesel said:
Before and after your two observer pulse detection, the third observer, who receives the light pulse from one, then the other source perceives what? That the light pulses weren't simultaneously emitted? Isn't this what SR predicts? If it does then SR is just another lying theoretical perception scammer..

I keep trying to get us talking about the same thing, and you keep changing the lingo. For now, let's skip pulses and third observers. I have asked specific questions so we can agree about the examples we are discussing, so I repeat (2 supernovae photon sources, 2 co-located observers in relative motion):

So from my perspective, the question is the observation of 2 events. What is simultaneous is the receipt of photons of light from the distant sources. Clearly, that does not make the physical events simultaneous in any sense.

Now, suppose, we have 2 observers, moving with respect to each other. Their paths intersect at precisely the moment that photons from 2 supernovae arrrive. In my opinion, SR predicts that both observers will acknowledge the simultaneous observation of the supernovae. Do you agree a) that SR predicts this, and b) that this "simultaneous observation" will be the result?
 
  • #90
What are simultaneous events.

Hurkyl said:
How does one tell if two events are simultaneous?
A stationary observers triggers two light sources equidistant from M. The light pulses arrive at M simultaneously. Hence the lights were pulsed on simultaneously.

If the only measurement of an observer is the simultaneous arrival of light pulses at some point M, then the only thing that may be concluded is that M is the midpoint between two wave frionts, with nothing said about the location or sequence of pulses of the sources.

If two or more events are simultaneous in time, wherever located, the event are simultaneous [though some claim SR may provide a different perception of the events being simultaneous or not depending on the observers frame - moving or not.

If you haven't been following this thread the discussion point revolves around the perceptions of observers being different for obserservers in different frames. It has claimed that SR says what is simultaneous for an observer in a stationary frame is different [or may be different] than that perceived by a moving observer, or from my position I distinguish between perceptions and physical events.
 
  • #91
DrChinese said:
First of all. your statement about the "one and only one midpoint" of 2 expanding spheres is factually incorrect. Spacetime is curved (GR), and even in QM alone there is no such point. Even if it were true - which it is not - what would the significance be of such a point? I am still missing the entire line of reasoning related to this.

You use a theory to disprove the fact of the invariant midpoint of two wave fronts. That doesn't convince me, especially when I see the shaky legs Sr is on regarding simultaneity.

DrChinese said:
Second, you are making a logic error when you assume there is an absolute space and then use this to attempt to disprove SR (this tautology has been pointed out to you previously by others).

I do not assume as absolute space. You are misquoting me or misstating me, or I wrote poorly. I attempted to make the point that the invariance of midpoints of moving wave fronts provides a mechanism of determining an absolute space, or locations in space in general, trillions to the trilion power of such points. If the "midpoint theory" happens to conicide with physical fact, then what is the tautology of using this against SR? I probably stepped over the line a time or two , but my point has been primarily focussed on the question of simultaneity as expressed by SR. If the midpoint theory is true then nothing need be said regarding SR, it is just one of those instances where res ipsa loquitor.

DrChinese said:
And third, my "obsession with observers" is firmly grounded in the philosophy of an objective science. So don't expect that I will see your criticism as such.

The "firmness" of your [the SR theoretical industry's] grounding in objective science is at issue, it is the issue. You are being forgetfull of the thread we are involved in. You are familiar with the cousin of thii point seen in the debates of QM where some have argued, 'the wave function collapses when measured by a conscious being'? Talk about observational egotism!

DrChinese said:
You didn't address it, so I assume you are now in agreement with my A. point: that an observer cannot determine the source point of photons detected.

If that is the only infromation available then the source of the photon is unknown and effectively unknowable, almost reaching the state of nonlocality.
 
  • #92
Doc Al I - used a statement you made when I posted a reply to DrChinese and also referred to a thread, "The question of simultaneity" in the "Relativity Forum" authored by Icky. You and I were participants in that thread..
geistkiesel
 
  • #93
geistkiesel said:
You have proved my point. Yes simultaneity is an objective fact. You are saying the rea;ity is what the observer perceives. I say the reality is independent of what obsevers perceive.
So let me get this straight. You're basically saying: "Reality" is whatever you declare it to be, regardless of observations, measurements, etc.

Sorry, but that's a perfect definition of fantasy, not reality. Physics is concerned with what one can: measure, observe, experience, test.
 
  • #94
If you haven't been following this thread the discussion point revolves around the perceptions of observers being different for obserservers in different frames. It has claimed that SR says what is simultaneous for an observer in a stationary frame is different [or may be different] than that perceived by a moving observer, or from my position I distinguish between perceptions and physical events.

The thing is, Einstein gives an operational definition of terms. For example, there are procedures that can physically performed to identify something that SR calls "simultaneity in a given reference frame". SR's conclusions are certainly physicially meaningful, though you may disagree with the words chosen for them (such as "simultaneous").



The problem I'm having with your ideas is that there doesn't seem to be any way to actually determine whether two things are simultaneous; you describe it as if it is something one just knows.
 
  • #95
geistkiesel said:
A stationary observers triggers two light sources equidistant from M. The light pulses arrive at M simultaneously. Hence the lights were pulsed on simultaneously.

If the only measurement of an observer is the simultaneous arrival of light pulses at some point M, then the only thing that may be concluded is that M is the midpoint between two wave frionts, with nothing said about the location or sequence of pulses of the sources.

geistkiesel,

It is getting frustrating because the words mean something entirely different to you than to others. For example, the statements you made above do not define a "midpoint" under any type of spacetime that I am familiar with - classical or Einsteinian. This is why I keep trying to pin down a specific example to discuss. If you do not want to discuss a specific example that we can all understand, please say so.

2 spheres in 3 space intersect at zero, one or an infinite number of points, depending on their relative size and position. This is true whether or not the spheres are equal in size. In your example above, you mention a point M which is equidistant from two photon sources. There are an infinite number of such points in classical 3 space.

Questions:

a) Is the observer in your example located at M?
b) And is M intended to represent a point equidistant from the photon sources, with distance to iM set as a minimum?
c) What significance is the point M to determining whether SR is a good theory?
d) How does an observer at M determine the distance to the photon sources is equal?
e) Why do you refer to the light sources as pulses? Is there is significance to this language? Is there some reason not to use the term "photons" so we know what you are referring to specifically?

-DrC
 
  • #96
geistkiesel said:
I do not assume as absolute space. You are misquoting me or misstating me, or I wrote poorly.

Well, you said:

"The statement regarding the midpoint of expanding EM spheres was intended to demonstrate the existenxcce of an absolute space."

-and-

"Reference to absolute space and time: For the case of two moving wave fronts existing in the universe, do you agree that all observers in all platforms will determine the location of one and only one midpoint of those expanding EM spheres? and that everyone will determine the exact same location of that midpoint? The midpoint cannot drift unless the wave fronts drift, which would mean that the wave front velocity is variant,which would mean tha 'c' varies. Do you want to do this?

There can be only one collision of the wave fronts at the same place and time, universally.

I conclude for the purposes of this duiscussion that we have found a satisfactory absolute space."

So perhaps you can see my confusion. I don't know of any experiment which has ever indicated an absolute reference frame. There are plenty that are done every day in which local coordinates are used. So I am trying to determine what role - if any - absolute space figures into your critique of SR. Is it critical to your example(s)? If not, fine, that will make our discussion simpler.
 
  • #97
DrChinese said:
Well, you said:

"The statement regarding the midpoint of expanding EM spheres was intended to demonstrate the existenxcce of an absolute space."

-and-

"Reference to absolute space and time: For the case of two moving wave fronts existing in the universe, do you agree that all observers in all platforms will determine the location of one and only one midpoint of those expanding EM spheres? and that everyone will determine the exact same location of that midpoint? The midpoint cannot drift unless the wave fronts drift, which would mean that the wave front velocity is variant,which would mean tha 'c' varies. Do you want to do this?

There can be only one collision of the wave fronts at the same place and time, universally.

I conclude for the purposes of this duiscussion that we have found a satisfactory absolute space."

So perhaps you can see my confusion. I don't know of any experiment which has ever indicated an absolute reference frame. There are plenty that are done every day in which local coordinates are used. So I am trying to determine what role - if any - absolute space figures into your critique of SR. Is it critical to your example(s)? If not, fine, that will make our discussion simpler.

Good question DrChinese. I was merely answering the claim that there is no "absolute space", by constructing a space that is absolute, theoretically speaking. Consider the number of "midpoints" that dot the universe. The difficulty in mesurement is moe a problem in engineering. Other than in my links I haven't pressed the issue, and even in the links, the issue wasn't discussed in those terms you've just amplified.

Take a look at the links. I think you will find that the moving observer can make all the calculations using his own frame of reference in order to determine if the pulsed light sequences were simultaneous to him, he only just crossing the midpoint of the stationary frame. when the lights pulsed. The examples of the moving observers all meeting at the midpoint differs from one of my link hypotheiticals that used AE's example in the dog eared relativity book.So I'll get a new copy.
 
  • #98
Midpoint of expanding EM spheres.

DrChinese said:
geistkiesel,

It is getting frustrating because the words mean something entirely different to you than to others. For example, the statements you made above do not define a "midpoint" under any type of spacetime that I am familiar with - classical or Einsteinian. This is why I keep trying to pin down a specific example to discuss. If you do not want to discuss a specific example that we can all understand, please say so.

2 spheres in 3 space intersect at zero, one or an infinite number of points, depending on their relative size and position. This is true whether or not the spheres are equal in size. In your example above, you mention a point M which is equidistant from two photon sources. There are an infinite number of such points in classical 3 space.

Questions:

a) Is the observer in your example located at M?
b) And is M intended to represent a point equidistant from the photon sources, with distance to iM set as a minimum?
c) What significance is the point M to determining whether SR is a good theory?
d) How does an observer at M determine the distance to the photon sources is equal?
e) Why do you refer to the light sources as pulses? Is there is significance to this language? Is there some reason not to use the term "photons" so we know what you are referring to specifically?

-DrC

A. I am constructing a theoretical midpoint that is invariant, that is all. Any two wave fronts, wherever located and unrelated to the technical or reasonable ability to measure the situation have a midpoint that is invariant. If the concept is new to you, well then join the club, becaue it is new to me also, but coneptually and physically the description should hold. Do you see a flaw? Applying the description to our hypotheticals is reasonable. Look at my links again , I make much of this in cocnstructing the method for determining whether the photons were emtited simultaneosly.

B. If I understand you yes. The midpoint can be of the type we have been discussing in our hypotheticals, or on the grander scale of simultaneously or even nonsimultaneously errupting supernovae. Liike I mentioned, an expanding wave front chugging along for a million years has a huge number of midpoints between itself and all the other wave fronts in the universe. When a new pulse (photon) comes along, for any reason, another midpoint between the new wave front and the ancient is established.

C. In the hypotheticals we have been discussing, the midpoint is everything. For instance I argued in a previous thread to someone claiming one of the lights had to be pulsed on earlier than the other that he could be correct up to a point. Without any information locating a source, then the wave front is all that matters and that wave fronts could have been pulsed on at any time. I have not expressly used the used the term 'absolute space' in any argument that I recall, and only offered the concept here that under the conditions that the construct of the 'midpoint system' is an effective absolute space, then if SR denies the concept of absolute space SR would would be defective for that reson, right? You and I are debating an issue. You make a statement, any statement, denying the physical reality of 'absolute space'. I take this as meaning you are jusifying SR or something of which I am completely ignorant, but at least I was able to blunt the claim of any making the habitual claim of the lack of an ' absolute sapce' . OK I may have been in the dark, but so what? If one of an infinite number of inebriated Peruvian llamas suddenly handed us a single piece of paper with all the issues laid to rest with all the ambiguities, would you deny using the llama paper, just because it came from a llama?, an inebriated llama at that? or would the truth of the matter be sufficient?

D. Without some information other than the detection of the photons all the observer can determine is the point of collision, that we have been referring to as the "midpoint", can only be determined with certainty as the midpoint of the oncoming wave front originating from the sources wherever located.
In a hypothetical where the moving ovserver passes he midpoint just as the light sources are pulsed on and subsequently measuring the oncoming light then the light from the rear the observer can determine if the "midpoint" he crossed is the midpoint of the sources (because that is a given,) of light, but his information is restricted to the midpoint of the colliding wave fronts. Do you follow what I am saying? The moving observer, knowing his velocity and the fact he zeroed his timer when crossing the midpoint can determine if the subsequent pulses (photons) were emitted simultaneously, this moving observer can only do this with respect to (analysis of) the wave fronts of the emitted lights, each wave front moving at equal velocities and each wave front is located equidistant from the midpoint from the instant the pulses (photons) were turned on.

e. No there isn't any reason I cannot use 'photon' in place of 'pulse'. Was this terminology that confusing?
 
  • #99
Doc Al said:
So let me get this straight. You're basically saying: "Reality" is whatever you declare it to be, regardless of observations, measurements, etc.

Sorry, but that's a perfect definition of fantasy, not reality. Physics is concerned with what one can: measure, observe, experience, test.

No, you are missing the point. A simultaneous event say in a stationary frame is physically simultaneous everywhere in the universe, and if your perceptions, weighted as they are by some theory that says you can perceive something different and that 'different' is claimed as a physical reality then you are accepting fantasy as reality.

And since you are here take a look at this link for a sense of the value of measurement I place on events.http://frontiernet.net/~geistkiesel/index_files/

Two moving observers are approaching the mid point of two pulses of light emitted simultaneously in the stationary frame. One post argued that each of them using SR determines that the light behind them was turned on first. This was offeered to me for what reason I am unable to determine, but giving each observer a piece of theoretically fabircated nonsense, contrary to the stationary reality in the stationay frame such as I just decribed is silly.

Let me guess, you are going to respond that no, it is I who am silly right?, or something like this? right?

Your post doesn't have a lot of simultaneity concepts vis a vis SR, if any, are you just jumping in here for the fun if it, or did you just intend to distract the thread by some stupid inference assigned to me that I never made?
 
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  • #100
Hurkyl said:
The thing is, Einstein gives an operational definition of terms. For example, there are procedures that can physically performed to identify something that SR calls "simultaneity in a given reference frame". SR's conclusions are certainly physicially meaningful, though you may disagree with the words chosen for them (such as "simultaneous").



The problem I'm having with your ideas is that there doesn't seem to be any way to actually determine whether two things are simultaneous; you describe it as if it is something one just knows.

I don't see how you could have missed the link I have been placing here and there if you have been following this thread as you say.

Let me make it trivially easy for you to determine if two events are simultaneous, where some have informed me SR says it can't be done.

http://frontiernet.net/~geistkiesel/index_files/
 
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  • #101
Simple simultaneity example drawn from a random webpage.

DrChinese - I found this example of a discussion on simultaneity on the internet. Do you agree with the conclusions and analysis? Explain. It is a faily simple hypothetical.

Do you agree with the conclusion this link?
 
  • #102
Is it just me? or does anyone actually get what those clock shooting out pictures at a constant rate which astronuats see which they then average off ( which is obvious without demonstration they'd be equal) are supposed to prove.

I'm not really sure what ur on about, but i suggest redoing that animation and starting the astronaut being to one of the sides and not in the middle :-/

cuz if he's in the middle of course he will see the light at the same time but if he's on the sides he will see 1 first before the other.

Also the astronauts on the side r seeing like 29 and 30 when the one of the other side is seeing 20 and 39 or wut ever, but they r different even though avged off they may be the same they r still differerent.


i hope at least some people understand me..
 
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  • #103
O = supernova
-> = Light
X = Person
. = space
= = 2 light beams ( just to make this more understandable)



.......X "do de do de do".....
A)O-------->......... <-----------O
......X "oh wow a super nova"...X..." I can see a supernova"




.......X "wow 2 super nova at the same time!"...
B)O-------------------------><----------------------------O
......X "wow that was cool"...X..."that is a cool supernova"



.......X "that was 2 cool supernova"
C)O-----------<========================>------------O
......X "whoa another 1!"...X..."hey look another supernova"



.......X "no they both happened at the same time"
D)O==========================================O
......X .........X.....
"The Super nova on this side happened first"..."No the super nova on this side happened first"


Am i right in showing that diagram thingy ( if you can even read it)
 
  • #104
Gelsamel Epsilon said:
Is it just me? or does anyone actually get what those clock shooting out pictures at a constant rate which astronuats see which they then average off ( which is obvious without demonstration they'd be equal) are supposed to prove.

I'm not really sure what ur on about, but i suggest redoing that animation and starting the astronaut being to one of the sides and not in the middle :-/

cuz if he's in the middle of course he will see the light at the same time but if he's on the sides he will see 1 first before the other.

Also the astronauts on the side r seeing like 29 and 30 when the one of the other side is seeing 20 and 39 or wut ever, but they r different even though avged off they may be the same they r still differerent.


i hope at least some people understand me..

If you would describe the animation and the parameters of the problem as you see it, it may clear things up. I didn't get it. This is not to say you haven't gor valid point, I just didn't get it.
 
  • #105
Gelsamel Epsilon said:
O = supernova
-> = Light
X = Person
. = space
= = 2 light beams ( just to make this more understandable)



.......X "do de do de do".....
A)O-------->......... <-----------O
......X "oh wow a super nova"...X..." I can see a supernova"




.......X "wow 2 super nova at the same time!"...
B)O-------------------------><----------------------------O
......X "wow that was cool"...X..."that is a cool supernova"



.......X "that was 2 cool supernova"
C)O-----------<========================>------------O
......X "whoa another 1!"...X..."hey look another supernova"



.......X "no they both happened at the same time"
D)O==========================================O
......X .........X.....
"The Super nova on this side happened first"..."No the super nova on this side happened first"


Am i right in showing that diagram thingy ( if you can even read it)


I assume the reference to supenovae is directed at the references in some of the previous posts. If so, what are you saying? I detect some cynicism and poking fun at the reference to the supenovae, which is fair game as far as I am concerned but other than that I do not read a specific message. For my part I ws making the point that two light, excuse me photon sources, simultaneosuly generated from opposite sides of the universe, whether measured or not, would be simultaneous as a physical event by any observer.

I do not wish to make an error in characterizing your post, but if you are making an attempt to trivialize the model you missed the inference that nobody is seriously ever going to make any try at measuing exploding supenovae located at opposite ends of the universe. Had this been the inference DrChinses and for sure Doc Al would have jumped all over it. Is my assesment correct, or what?

In any event welcome to the forum.
 
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