A New Simultaneity Method for Accelerated Observers in Special Relativity

I don't agree that the CMIF simultaneity method is any more representative of Special Relativity than my new simultaneity method.

Special Relativity is SILENT on simultaneity for an observer who accelerates.

That is where reality and Mike's brain part ways. In order to maintain this fantasy, he has to resort to claiming that the CMIF simultaneity (which is the simultaneity that results from extended sets of Einstein-sycnchronsed clocks at rest in inertial frames) is only applicable to reference frames which have been perpetually inertial.

This means he has to resort to changing things from being frame-dependent in SR, (such as "simultaneity is frame-dependent") to things being person-dependent in Mike's SR (such as "her age is currently 40 according to the perpetually inertial people in her reference frame, but not according to the guy who recently decelerated, his simultaneity is different, even though he is at rest in that same frame!").

It is bad enough to patch all of these unnecessary things onto an established theory ad hoc, but to claim the theory was like that all along is just insulting.
 
They don't disagree on the entire return leg about ANYTHING that is happening locally ... but during the DI, they disagree about what is happening at a distance,

Let me confirm what you mean by "happening locally", because I think there is one example where there might be an ambiguity: Let's say, the ICMIO is looking at "Her" in the distance, and "He" is looking at "Her" in the distance, at the same place and the same time. If I correctly understand what you mean by "happening locally" then "He" and the "ICMIO" should be seeing the same event, in the same way, at the same time. Even though "She" is distant, the event of seeing "Her" is local.
 
Let's take the simplest case example, where the traveling twin changes from v=+0.577c to v=0.000c at the usual location (x=23.09 light years) at the moment when the traveling twin's clock says 32.66 years, as shown:

IG3ESak.png


All of the people in questions are now at rest in the stay-home twin's rest frame, and everyone agrees that her age at that time is 40 years old, because SR does not have things that are person-dependent, only things which are reference frame-dependent.

But let's say for a moment that SR is what Mike says it is, namely, totally silent on what speed of light should be for the traveling twin personally, because he has recently decelerated. All of the people located at x=23.09 can see (using their eyes + a telescope) that the stay-home twin's clock is showing 16.91 years. All of the perpetually inertial people can use the known speed of light and the known distance to calculate her current age as 16.91 + 23.09 = 40.00 years. But the traveling twin is different than all of those other people, because he has not been perpetually inertial. So what is the speed of light according to him? What is the distance between him and her according to him? It is whatever Mike says it is.

He can say the distance is still 23.09 light years for him, but the speed of light of the image of her clock was not 1 light year per year for him. Or he can say the speed of light of the image of her clock was 1 light year per year for him, but the distance is not 23.09 light years for him. Or he can say it is a combination of both.

All of this because he thinks SR is completely silent on the speed of light according to him (!) and because he thinks SR is completely silent on the distance between him and her according to him (!). Yeah, I'm pretty sure SR is not completely silent on those things.
 
he thinks SR is completely silent on the distance between him and her according to him (!). Yeah, I'm pretty sure SR is not completely silent on those things.

My own philosophy is that given any set of event coordinates, and the position, time, and velocity of any observer, you can establish the location of events according to that observer at that point in time, mostly by using rotation and lorentz transformations. The rotation transformation handles all the forward, up, down, left, and right issues, while the Lorentz transformation handles the future, past issues.

Here's my most recent treatment on the topic.

http://www.spoonfedrelativity.com/pages/TemporalFacing.php
 
My own philosophy is that given any set of event coordinates, and the position, time, and velocity of any observer, you can establish the location of events according to that observer at that point in time, mostly by using rotation and lorentz transformations. The rotation transformation handles all the forward, up, down, left, and right issues, while the Lorentz transformation handles the future, past issues.

Here's my most recent treatment on the topic.

http://www.spoonfedrelativity.com/pages/TemporalFacing.php

I'm not sure why you say it is your own philosophy, because the Lorentz transformations (LT's) sole purpose is to provide equations that anyone can use to do that, while maintaining all of the premises of SR. Unless you are of the Mike Fontenot school of "SR is totally silent on that," then all anyone has to do is use the LT's. They don't have to subscribe to any philosophy.

Anyway, I watched your first video, and I thought it was explained quite well. But the second video appears to be an accidental exact copy of the first one. Your notes say that the first 17 minutes are a review of part 1, but the whole video is only 13:41 minutes long, (the same length as the first).

Other than that, I found the fourth video interesting. I had not studied radar time that deeply before, because it seemed to me to be just another unnecessary add-on to SR, and not part of SR itself. But it is funny when you reveal that D&G still ended up with distant times shifting when someone "goes dancing" even though that was clearly what motivated D&G to create the add-on in the first place.

SR is complete as it is, excepting gravity. If it doesn't specifically say that an inertial frame can only be one that has been perpetually inertial, then that does not mean it is totally silent on that subject allowing one to interpret it to mean that if one wishes. Inertial frames are clearly defined in SR, and not open to interpretations such as that (Mike's).

Likewise, relativity of simultaneity is a clearly derived result of the premises of SR. When two inertial frames are in uniform relative translation with respect to one another, events which are spacial-separated along the direction of the relative motion between the frames WILL NOT BE SIMULTANEOUS in one frame, if they ARE SIMULTANEOUS in the other frame. Mike's whole goal is to violate that, because he needs to make the event "Traveling twin's age is 32.66" simultaneous with the event "Stay-home twin's age is 26.67" in BOTH the traveling twin's outbound frame, AND the traveling twin's new frame, (after the traveler decelerates to v=0.000c or turns around and heads back at v=-0.577c or whatever else he might do). Thus a clearly derived result of SR, namely relativity of simultaneity as explained above, is DENIED OUTRIGHT under the guise of "SR is totally silent on that". It is almost a blasphemy, lol.
 
Last edited:
Let me confirm what you mean by "happening locally", because I think there is one example where there might be an ambiguity: Let's say, the ICMIO is looking at "Her" in the distance, and "He" is looking at "Her" in the distance, at the same place and the same time. If I correctly understand what you mean by "happening locally" then "He" and the "ICMIO" should be seeing the same event, in the same way, at the same time. Even though "She" is distant, the event of seeing "Her" is local.

Yes, that's correct. The disagreement between him and the ICMIO (for a while, after he changes velocity) is over how much she aged while those images were in transit.
 
Your notes say that the first 17 minutes are a review of part 1, but the whole video is only 13:41 minutes long, (the same length as the first)

I'll try to fix that soon. In the meantime, if you like, you can watch the video on youtube at

I'm not sure why you say it is your own philosophy,

Have you ever heard anyone say "SR is valid only locally"? I have heard this phrase quite a number of times, and it seems at odds with the philosophy that the Lorentz Transformations operates on the coordinates of all events in spacetime. So, my philosophy is that SR is valid globally.

Thus a clearly derived result of SR, namely relativity of simultaneity as explained above, is DENIED OUTRIGHT under the guise of "SR is totally silent on that". It is almost a blasphemy, lol

Look in the Wikipedia discussion archive 5 for Lorentz Transformations, here: https://en.wikipedia.org/wiki/Talk:Lorentz_transformation/Archive_5

Under the header "Delete irrelevant animation", the user, there, whose name seems unpronounceable, says that the animation there, which demonstrates exactly how events move forward and backward in time as the Lorentz Transformations are performed, for a given observer, are "irrelevant" to the Lorentz Transformations. This gives me the impression that many people are of the philosophy that SR does not actually move events around, but just puts new labels on them.
 
Yes, that's correct. The disagreement between him and the ICMIO (for a while, after he changes velocity) is over how much she aged while those images were in transit.

Alright. I will say, then, there is nothing, in principle, that would prevent the traveling twin from using your method, or even arguing that his method was better than other methods. "Better" being a key word here, because it is an opinion word. Opinions as to what is better can be formulated on whatever you designate to be an important property you want a method to satisfy. (A rubric)

The method I think is better, is for "him" to simply take a "tangent" with slope dx/dt = v, and the hyperpendicular simultaneity line, with slope dx/dt =1/v, and see where that simultaneity line intersects "her" world-line. Whatever age she is at that intersection is what "he" would say "her" age is now.

One thing I like about this method is that it should highlight changes in the relativity of simultaneity, as he accelerates toward her, she has a sudden lurch forward in age. Even skipping years, if he accelerates instantaneously. If you regard the acknowledgment of the relativity of simultaneity as a bad, thing, though, highlighting it would not be in your rubric.
 
Have you ever heard anyone say "SR is valid only locally"? I have heard this phrase quite a number of times, and it seems at odds with the philosophy that the Lorentz Transformations operates on the coordinates of all events in spacetime. So, my philosophy is that SR is valid globally.
Your philosophy is then one of denial of facts. Under SR, given any two objects E and F separated by X light years in the frame in which E is stationary, light from F will get to A in X years. Not true of our universe, where if F is sufficiently distant, light will never reach E in any amount of time. So much for SR describing the universe on a large scale.

On a more local scale, if I shine a laser to a reflector on the moon and time the round trip, I will get a faster measurement for the speed of light than if I did the same experiment on the moon using a reflector here on Earth. SR asserts the two should be the same, but in both cases (the distant F and the moon thingy), the conditions of SR (the parts that make it special) are not met. Only locally are they met.
 
Not true of our universe, where if F is sufficiently distant, light will never reach E in any amount of time. So much for SR describing the universe on a large scale.

The universe you are describing is only a model.

On a more local scale, if I shine a laser to a reflector on the moon and time the round trip, I will get a faster measurement for the speed of light than if I did the same experiment on the moon using a reflector here on Earth.

I agree, here, but what I'm in agreement with is that "SR is NOT valid locally".
 
The universe you are describing is only a model.
I am describing our actual empirical universe, not a model. There is really an event horizon beyond which light will never reach us. Light round trip to the moon and back really will be measured faster than light round trip from the moon and back. GPS clocks run faster than Earth clocks even in Earth frame where the GPS clocks are moving much faster. SR is mute on all that because SR cannot explain any of these observations.
 
I am describing our actual empirical universe, not a model. There is really an event horizon beyond which light will never reach us.

What you are describing is General Relativity and Cosmology. This thread is about Special Relativity. In Special Relativity, it is assumed that there are no significant masses present, spacetime is flat, and it is valid over arbitrarily large distances.
 
Last edited:
I am describing our actual empirical universe, not a model.

Even if you were correct about the universe, I would still call your description of it "a model."

Emperical means "based on, concerned with, or verifiable by observation or experience rather than theory or pure logic".

Can you tell me of an observation that has been done which has demonstrated that your model is correct, and the Milne model is incorrect? Both models have an explanation for the Cosmic Microwave Background Radiation. Both models have an explanation for Hubble's Law. And if you account for temperature in the early universe, both models have an explanation for cosmic inflation, as I recently described here: https://www.researchgate.net/public...Cosmological_Inflation_in_Minkowski_Spacetime



What you are describing is General Relativity and Cosmology
My philosophy is that cosmology and Special Relativity should not be separated. Many people treat them as though the Lorentz transformation stops functioning as soon as one adds a little gravity into the mix. I think that's as absurd as suggesting that rotation stops working as soon as you throw gravity into the mix.

If I turn my head 90 degrees to the left, all of the objects, no matter how far away from me, rotate 90 degrees to the right in my point-of-view, corresponding to a 90 degree clockwise rotation transformation. It does not matter how far away they are, and gravity has no effect on this. So how can anyone justify the idea that if I accelerate to half the speed of light, only "local" events will respond to the Lorentz Transformation?
 
Alright. I will say, then, there is nothing, in principle, that would prevent the traveling twin from using your method, or even arguing that his method was better than other methods. "Better" being a key word here, because it is an opinion word. Opinions as to what is better can be formulated on whatever you designate to be an important property you want a method to satisfy.

I certainly agree with all that. The good characteristics of my simultaneity method, in my opinion, are that it has no discontinuities in the age correspondence diagram (ACD), it is causal, its ACD is easy and quick to compute, and the home twin's age NEVER decreases ... i.e., she never gets YOUNGER, according to him. Some of these characteristics are also characteristics of the other three simultaneity methods, but none of the other methods have ALL of these characteristics.

The method I think is better, [...]

When I first read that description, I initially thought you were proposing a 5th simultaneity method. But after a more careful reading, I think you are just talking about the CMIF method.

If you regard the acknowledgment of the relativity of simultaneity as a bad thing [...]

If you are talking about me and my method in the above statement, then I don't understand why you are saying that. The relativity of simultaneity is just a statement that not all observers draw the ACD (her current age, plotted versus his age) the same way. None of the four simultaneity methods contend that the relativity of simultaneity is a bad thing. They each produce an ACD that differs from the ACD that the home twin produces, and that's their goal.
 
My philosophy is that cosmology and Special Relativity should not be separated.

I think they SHOULD be. Halc is arguing that SR is only local, because Cosmology (and in particular, inflation) results in some signals never reaching us. But under the ASSUMPTIONS of SR itself, there are no significant masses anywhere near our proposed trip, and there is not any spatial inflation happening that affects our trip ... space by definition is completely static and flat in SR, and it is infinite in extent.

Even in the real universe as it is (or as we currently think it is), if we could take a relativistic-speed trip out to 50 lightyears or so, and which avoided going anywhere near any large stars or blackholes, the results obtained using special relativity would very well approximate what actually happens on the trip. It's wrong to think SR is no longer useful, just because we now know a lot about GR and Cosmology (specifically, about blackholes and inflation).
 
I think they SHOULD be. Halc is arguing that SR is only local, because Cosmology (and in particular, inflation) results in some signals never reaching us. But under the ASSUMPTIONS of SR itself, there are no significant masses anywhere near our proposed trip, and there is not any spatial inflation happening that affects our trip ... space by definition is completely static and flat in SR, and it is infinite in extent.
Oh, I agree that SR is fine for the thought exercises in this thread. I was just commenting on Doolin's 'philosophy'.

SR is local because it has no compensation for dark energy or for gravity, and I picked examples illustrating each to show why it fails outside of the special conditions where it is valid.
 
Here is an example of what I mean by saying SR is valid globally: "Stellar aberration" was detected (empirically) by James Bradley in 1727.

That effect is easily modeled by the Lorentz Transformations. It essentially causes their images to be always Lorentz boosted forward towards the direction of Earth's motion around the sun, just a bit. There's no gravitational pull or dark energy that prevent the Lorentz Transformations from operating on events that are an infinite distance from earth.

Notice, here, I use the word "model" whether or not I believe the model is correct. I believe that the Lorentz Transformations give the correct model for Stellar Aberration. However, scientifically speaking, I also think one could find a way of modeling the phenomenon using Galilean Transformations with the sun embedded within a universal ether.

because Cosmology (and in particular, inflation) results in some signals never reaching us

Empirically speaking, all we have to go on is redshift and magnitude measurements.

A model that claims "some signals never reach us" is not an entirely empirical model, because any signal that will never reach us would never be observed or experienced; hence the opposite of empirical.

SR is local because it has no compensation for dark energy or for gravity,

Regarding gravity, I think this is the third time I've said this: gravity is a local phenomenon, so it would make more sense to say that SR is global, while gravity is local.

Regarding dark energy, it is energy that has never been detected, so again, the opposite of "empirical".

It is also goes somewhat counter to the scientific method that the supposedly "correct" model of the universe is one that makes a prediction that has so far never been observed. In introductory science, when your hypothesis predicts a phenomenon, and then, when tested, that phenomenon does not occur, that hypothesis does not become theory. Instead, one is supposed to go back to the observation stage with an open mind to form new hypotheses.
 
My monograph on "A New Simultaneity Method for Accelerated Observers in Special Relativity" is available on Amazon for $5.00. You can find it by searching on "simultaneity method".
 
My new simultaneity method is an alternative to the commonly used co-moving-inertial frames (CMIF) simultaneity method. I personally prefer the CMIF method to my method, but some people dislike the CMIF method because it produces an instantaneously changing current age of the home twin (she), according to the traveling twin (he), when he instantaneously changes his velocity. That instantaneous changing of her age, according to him, is especially abhorrent to some people when it is negative, i.e., when she instantaneously gets YOUNGER, according to him. I personally am not bothered by that (and neither is the well-known physicist Brian Greene, as was shown in his PBS Nova series on "The Fabric of the Cosmos"). My simultaneity method provides an alternative "safe haven" for those people, because it has no discontinuities (either positive or negative) in her age, according to him.

My simultaneity method is described in detail in a monograph published by Amazon, available for $5.00. You can find it most easily by searching on my complete name: "Michael Leon Fontenot" (with the quotes).

That monograph addresses only the issue of how to determine her age according to him, versus his age. I.e., it only addresses simultaneity. But I have also recently worked out what my method has to say about how he can determine their distance apart, according to him, at any instant in his life. That addition makes my method a complete coordinate system for him. Here is a description of how my method determines their separation, according to him.

The CMIF method and my method give the same answer to the question "What is the distance between the home twin (she) and the traveling twin (he), according to him" ONLY when there is no discontinuity in the CMIF solution. There is no discontinuity in their separation in the most common version of the twin paradox, where he reverses course at the turnaround point, but comes back at the same speed as he used on the outbound leg.

But if he uses a DIFFERENT speed on the return leg than he used on the outbound leg, the CMIF solution gives a discontinuity in their separation when the speed changes (according to him). My method never produces a discontinuity.

For example, suppose his speed on the outbound leg is 0.57735 ly/y (gamma = 1.2247). (That case is advantageous, because the angle of his worldline wrt her worldline (the horizontal axis) is 30 degrees, and can be easily drawn with a 30-60-90 plastic triangle.) Suppose she is 40 years old when he turns around. He is 32.66 years old then. Then suppose his new speed is -0.866 ly/y (gamma = 2.0). When they are reunited, she is 66.67 years old, and he is 46.0 years old.

For the above case, we can plot their separation at each instant of his life, according to him, for both the CMIF method and for my method. I call that diagram the "SAAOD", for "Separation According to the Accelerated Observer Diagram." Their separation is on the vertical axis, and his age is on the horizontal axis.

The first straight line segment starts at the origin, when he is zero years old, and their separation is zero ly. It slopes upward at a 30 degree angle. It reaches its peak when he is 32.66 years old, and their separation is 18.86 ly.

When he changes his speed to -0.866 ly/y, their separation instantaneously drops to 11.55 ly, according to the CMIF method. Then, from there, their separation declines linearly with a slope -0.866 until their reunion. (That last straight line segment makes an angle of approximately 41 degrees wrt the horizontal axis).

In contrast, in my method their separation doesn't instantaneously change. Instead, it decreases linearly with a slope of -2.047 from its peak at 18.86 until his age reaches 38.85 years old, and their distance reaches 6.188. (That endpoint corresponds to when he receives a light pulse that she sends at his turnaround). Then, at that point, the slope of the line decreases to -0.866 until their reunion. The two methods coincide along that last segment.
 
Last edited:
In contrast, in my method their separation doesn't instantaneously change. Instead, it decreases linearly with a slope of -2.047 from its peak at 18.86 until his age reaches 38.85 years old, and their distance reaches 6.188. (That endpoint corresponds to when he receives a light pulse that she sends at his turnaround). Then, at that point, the slope of the line decreases to -0.866 until their reunion. The two methods coincide along that last segment.

I have just verified that the above segment is indeed a straight line. The verification is similar to what I did for the linearity of the middle segment in the age correspondence diagram (the "ACD"), which I described in Section 8, titled "Pulses Partly in Both Halves of the Minkowski Diagram", of my monograph.

On the Minkowski diagram, first find the vertical line descending from the traveler's (his) worldline at his turnaround point, down to the horizontal axis (her worldline). Mark the half-way point on that vertical line, and call it "point Q". Then draw a light pulse being sent by her, at such a time in her life that the pulse passes through that half-way point, and continues on until it reaches his worldline. Mark that point on his worldline as point R. His age is 35.75 then.

According to her, their separation at the turnaround is 23.094 ly. And according to her, that half-way point is at distance 11.547 ly from her. According to a perpetually-inertial observer traveling at 0.57735 ly/y (with gamma = 1.2247), that distance is 11.547 / 1.2247, or 9.43 ly from her. Similarly, a perpetually-inertial observer traveling at -0.866 ly/y (with gamma = 2.0), concludes that that pulse travels a distance 3.09 ly from point Q until it reaches the traveling twin at point R. So the traveling twin (he) then concludes that the distance between him and her at the instant he receives that pulse is 9.43 + 3.09 = 12.52 ly. If, on the SAAOD (Separation According to the Accelerated Observer Diagram), you plot the separation 12.52 ly when he is 35.75 years old, you will see that it does indeed lie on the midpoint of the previously described straight line.
 
Back
Top