SR with Apparent Simultaneity

[phyti]

Right, well when I spoke of "standard simultaneity vs apparent simultaneity" you said I was speaking of RoS. The former statement ("an example supernova millions of light years away that is seen now occurred millions of years ago") corresponds with standard simultaneity, while the latter ("a supernova seen now is occurring now") corresponds with apparent simultaneity.

 

Awareness/detection of an event is always historical or after the fact. Thus it is impossible for an event and its detection/awareness to be simultaneous.

 

[md65536]

Awareness/detection of an event is always historical or after the fact. Thus it is impossible for an event and its detection/awareness to be simultaneous.

Why?

 

If you assume that standard simultaneity is physically correct, then it is impossible in SR. However if you don't, and instead suppose that apparent simultaneity is possible, you can still obtain a model that is consistent with SR. (I make no claim that SR is wrong in any way, only that the classical assumption that defines simultaneity is superfluous.)

 

Is it physically impossible for an effect to be simultaneous with its cause, or is that only a consequence of how you define simultaneity?

 

Some philosophers have argued reasons why it is impossible (eg. a symmetrical relationship between observers must be maintained, or instantaneous "action at a distance" is absurd), but those reasons don't hold up. The reason to accept any such arguments as far as I've seen, is the assumption that they're true. But if you don't assume that they're true, you can still produce a model which makes predictions identical to those of SR.

Edited January 7, 2014 by md65536

[DimaMazin]

Awareness/detection of an event is always historical or after the fact. Thus it is impossible for an event and its detection/awareness to be simultaneous.

 

We can't seriously consider relativity of simultaneity without its equation.Why someone instead of the creator should make the equation?

[md65536]

We can't seriously consider relativity of simultaneity without its equation.Why someone instead of the creator should make the equation?

The Lorentz transformation for time can be used to determine whether two events are simultaneous (according to standard simultaneity) in a particular inertial reference frame.

 

The relativistic Doppler equation can be used to determine whether two events appear simultaneous from a particular observer viewpoint. (The appearance of simultaneity doesn't depend on a simultaneity convention. Two events that appear simultaneous will do so whether you call them simultaneous or say they're separated by a transit time of light.)

Edited January 8, 2014 by md65536

[DimaMazin]

The Lorentz transformation for time can be used to determine whether two events are simultaneous in a particular inertial reference frame.

 

The relativistic Doppler equation can be used to determine whether two events appear simultaneous from a particular observer viewpoint.

Still I don't see equation of coordinates of times.

[DimaMazin]

[math]t' = \gamma (t - xv/c^2)[/math] for relative movement along the x-axis.

 

 

I have mistaken, that is equation of coordinates of times.

[md65536]

Earlier in the thread it was suggested that I submit this to a peer reviewed journal. I want to try to do that but I figure the quality of a paper has to be the highest that you can possibly make it before submitting it. I submitted it on these forums because it was at a point where I thought it was good enough for others to read and to ask for opinions.

 

Is it a waste of others' time to submit a paper that you think could still be improved? Do you get "one chance", and if a paper is too low quality will the journal blacklist you forever, or will they tell you to try again after specific improvements?

 

I want to remove any amateur statements, and any claims (opinions, interpretations, etc) that I can't back up purely with evidence and logic. Does anyone have any advice, like which specific ideas to focus on, explain better, or drop? Thanks.

[xyzt]

Earlier in the thread it was suggested that I submit this to a peer reviewed journal. I want to try to do that but I figure the quality of a paper has to be the highest that you can possibly make it before submitting it. I submitted it on these forums because it was at a point where I thought it was good enough for others to read and to ask for opinions.

 

Is it a waste of others' time to submit a paper that you think could still be improved? Do you get "one chance", and if a paper is too low quality will the journal blacklist you forever, or will they tell you to try again after specific improvements?

 

 

I suggested a few fringe journals for you to submit, they are the most likely to publish the stuff you wrote. Your stuff doesn't stand a prayer in a reputable journal.

 

 

 

I want to remove any amateur statements, and any claims (opinions, interpretations, etc) that I can't back up purely with evidence and logic. Does anyone have any advice, like which specific ideas to focus on, explain better, or drop? Thanks.

 

There is nothing there, there, as already pointed out. So, the best thing for you is to abandon the "paper".

Edited January 31, 2014 by xyzt

[phyti]

Why?

 

There is confusion here between the event and the perception/detection of the event. SR is also a theory of perception.

If you wonder if a star 10 ly distant is still there, while looking at it, you will have to check every night for 10 yrs or until it disappears,

whichever comes first.

Since the speed of an object relative to light cannot be determined,relative simultaneity is the next best thing. Synchronizing the fore

and aft clocks maintains the appearance of a pseudo rest frame.

 

 

[md65536]

There is confusion here between the event and the perception/detection of the event. SR is also a theory of perception.

If you wonder if a star 10 ly distant is still there, while looking at it, you will have to check every night for 10 yrs or until it disappears,

whichever comes first.

Since the speed of an object relative to light cannot be determined,relative simultaneity is the next best thing. Synchronizing the fore

and aft clocks maintains the appearance of a pseudo rest frame.

I understand that. There is no confusion about that.

 

I also understand the basis of this distinction between the event and the perception of the event. It is the assumption of standard simultaneity. Basically, Einstein started with a few assumptions: The two postulates of special relativity (1. physical laws are the same in all inertial frames, and 2. the speed of light as measured in any inertial frame is c), and the definition of simultaneity (which in literature is called "standard simultaneity").

 

The 2nd postulate and the assumption of standard simultaneity are very closely related, so much so that many authors (eg. in "philosophy of science" papers) treat them as one. However, to do that, you need a consistent definition of speed, and therefore of time and distance, and that isn't provided by the postulates. Many authors seem to treat rest distance as the definition of distance, and this works but it is an additional assumption carried over from classical science, and many don't acknowledge that. I believe that Einstein knew better, having concluded that time and distance are variable and intertwined, and realized that the definition of simultaneity needs to be specified independently of the 2nd postulate.

 

Einstein starts with a few assumptions and arrives at a consistent model of motion in flat spacetime. The assumptions aren't proven, but they're reasonable and they're consistent with reality, and they're probably true so I doubt that anyone could ever disprove any one of them.

 

However I'm arguing that the last one, the assumption of standard simultaneity, is superfluous. SR can be arrived at also by assuming a different simultaneity and using a different measure of distance.

 

So yes, in SR there is a difference in time between what is seen and what is happening, but that is not a consequence of SR itself. It is a consequence of the assumptions of SR, the definition of "time" used. It works and it is reasonable so it is accepted, yet it is also known that the convention that determines the simultaneity of distant events (which is needed in order to say that a 10 LY-distant event observed now and another event on Earth 10 years ago were *actually simultaneous* to the Earth-based observer) remains an assumption.

 

I'm not confusing this. I know that SR models a difference between the time of the event and its observation. But I'm trying to argue that this isn't a *necessary* component of SR. Not only does it work with alternative simultaneity, but the details turn out to be quite reasonable.

 

 

I don't know of anybody in science who has seriously considered alternative simultaneities, I think because the standard works perfectly well and is reasonable. There is no immediate "need" for any improvement. Some have looked critically at standard simultaneity: "Most attempts to negate the conventionality of this synchronisation* are considered refuted, with the notable exception of Malament's argument, that it can be derived from demanding a symmetrical relation of causal connectibility. Whether this settles the issue is disputed." [http://en.wikipedia.org/wiki/Einstein_synchronisation] Several "philosophers of science" have looked at alternative simultaneity and come to various conclusions, but I think they have not done an adequate job with the science of it (being lazy with postulates or definitions, etc).

 

* Note: The linked argument is about Einstein synchronization, and I've been talking about Einstein's definition of simultaneity, and I've been accused of confusing the two (perhaps), but the argument is still valid. If Einstein's definition of simultaneity is conventional, then Einstein synchronization must be conventional. Whether or not the reverse holds doesn't matter in this context.

Edited February 1, 2014 by md65536

[md65536]

On second thought, there's no point in assuming that Einstein's definition of simultaneity is right, or in challenging that assumption. There are not 3 main assumptions, just the 2 postulates. The definition is still needed, but it works as long as the postulates hold.

 

The question then shifts from whether or not Einstein's simultaneity definition is "right", but whether it is the only one or the best one. Since Einstein never assumes that the definition is right in a physically meaningful way, it doesn't matter if it is or not. All that matters is whether the resulting model and conclusions are right (ie. "correspond with measurements"), and they are.

 

 

Another example is a definition of speed. There are many different definitions (velocity, proper speed, etc); one isn't "right" while another wrong. The speed of light is c (whether by definition or measurement), and if one argues that there's a better measure of speed that doesn't change the fact.

 

I think I'll have to remove anything assuming or implying that a definition is right or wrong.

 

 

So far I have zero indication that anyone thinks there's any value in this.

[phyti]

md65536;

In fig.1 A is at the center of his black ship 10 units long and moving at .6c past U at the center of his green ship of 10 units long. When A and U are at x = 0, a flash occurs sending light in opposite directions along the x axis. Signals reflect from the ends of the U ship at t = 5, and return to U at t = 10. Signals reflect from the ends of the A ship at t= r1 and t = r2, and return to A at t = 12.5. For U the signals from the ends of his ship are simultaneous, and those for A are not.

For A in fig.2, r1 and r2 form a relative axis of simultaneity, with both events assigned to event r on A's timeline. The magenta line transforms U time to A time (12.5*.8 = 10), i.e. equal round trip times for A and U. The magenta line from r to (5, 0) confirms this.

Events as perceived in a pseudo rest frame are perceived the same as in an absolute rest frame.

 

Notice how the relative axis of simultaneity (r1-r2) is a true representation of the coordinates (x, t) of the events. Now enter the problem always lurking in the background, the inability to measure v/c, and therefore using reflected signals. If we stop here with the 2-way time, we have the most information to be gained since to continue is speculation.

Also neither the actual coordinates (per this example) or those assigned via the SR convention can be verified, due to the v/c issue. The simultaneity convention gets a plus for consistency and a minus for relocating events (events can't move).

To quote A. Einstein:

"That light requires the same time to traverse the same path A to M as for the path B to M is in reality neither a supposition nor a hypothesis about the physical nature of light, but a stipulation which I can make of my own freewill in order to arrive at a definition of simultaneity."[1]

I would agree with you, it is superfluous.

 

Hope this might help you in your consideration of alternate ideas.

 

1. Relativity The Special and the General Theory

Albert Einstein 1961 Crown Publishers Inc. pg 23

[md65536]

Also neither the actual coordinates (per this example) or those assigned via the SR convention can be verified, due to the v/c issue. The simultaneity convention gets a plus for consistency and a minus for relocating events (events can't move).

To quote A. Einstein:

"That light requires the same time to traverse the same path A to M as for the path B to M is in reality neither a supposition nor a hypothesis about the physical nature of light, but a stipulation which I can make of my own freewill in order to arrive at a definition of simultaneity."[1]

I would agree with you, it is superfluous.

 

Hope this might help you in your consideration of alternate ideas.

Yes, that helps, thanks. In his paper, Einstein never explicitly assumes anything about simultaneity, he simply makes a definition and uses it. Your quote proves that it was not just by chance of wording that Einstein did it this "bulletproof" way, but that he knew exactly what he was doing and did it intentionally. It is bulletproof because even if a "better" definition of simultaneity is ever found, it doesn't affect Einstein's definition.

 

Einstein defined simultaneity, but there are other ways that it can be defined (as several people have attempted throughout the past century), none of which have been convincingly demonstrated or broadly accepted to be superior to Einstein's definition.

 

Some kind of definition is still needed. Only the assumption part is superfluous. As an analogy, to measure time you need a frame of reference. You can choose one by defining your observer (as a stipulation, chosen by your free will). You don't have to "assume that a particular observer exists, and the experiment is observed by it". (This I think trips up many philosophers, assuming eg. that the observer is human, then getting too caught up in the details of biological processes of brain+eye etc).

 

It's not settled whether simultaneity can meaningfully be chosen just like frame of reference can, but I think it can.

[phyti]

It's not settled whether simultaneity can meaningfully be chosen just like frame of reference can, but I think it can.

 

If we generalize that all observers are moving, a reasonable assumption in a dynamic universe, then all simultaneity is apparent/relative, as indicated in fig.1 of my previous post. It’s the perception (in the mind) of simultaneous events. The moving observer always measures the ‘rest’ length for his spacecraft no matter what his speed and effects of length contraction. The observer in the center of a reflective ring perceives simultaneous reflections from all points on the circumference no matter what his speed, and in contrast to all other observers with a different velocity, who see the same reflections over an interval of space and time.

My point is, it’s altered perception. The observer is not exempt from the effects of time dilation and length contraction.

Unless a way is discovered to measure the speed of the observer to that of light, there is no way to assign observer independent coordinates to an event. If you consider r1 and r2 in fig.1, notice a forward event r2 occurs after the halfway point for the light path, and a rearward event r1 occurs before the halfway point. The SR convention including the synchronization of clocks if located at r1 and r2, is just to maintain the appearance of a pseudo rest frame for the moving observer. It has no significance beyond this (in agreement with the previous quote by A.E.

[md65536]

Thanks. I think I will have to rewrite before I can get my point across. You're using a different definition of apparent simultaneity than the one I cited in the paper.