A Question on One-Way Speed of Light

Ok. This is what confuses me: Physicists Just Smashed a Record to Achieve Quantum Entanglement in Space

(Edited after rereading article) I took this to mean that the photons were entangled at the satellite and sent to two different ground stations. At the stations the states were measured and compared to verify they had been entangled until the moment of being measured, and did not collapse on the way to the stations.

From Lisle’s article linked in my prior post:
I will show that the one-way speed of light is conventional. It is something that is stipulated by us, and is not an independent measurable property of the universe.

Is this legitimate? It is one thing to claim that the one way speed of light cannot be experimentally determined and it is allowable that light speed be infinite to an observer. The assertion that the speed of light is not a property of the universe but just a convention, however, requires some unpacking for me. In what sense is the speed of light then something “real” at all? Time is experienced as a ratio of things, number of ticks of a grandfather’s clock from sunrise to sunrise, number of rotations of the earth to signals back from voyager satellites, and so forth. Are there no such things as real ratios? Correct me if I’m wrong, but spacetime, along with time dilation and other effects, is still something very definite under special relativity. It sounds like Lisle is saying you can switch between ASC and ESC at your convenience (see the rest of his article). In other words, the space time geometry of the universe is not a property of the universe. What is going on here?

Just because many transforms may be mathematically legal does not necessitate they represent realities from which we get to choose at our leisure, any more there being many string theories which appear consistent does not make them all real, unless you want to make reality itself a subjective morass.

That actually seems right to me.

The word “geometry” comes from the idea of measuring the world. And all measurement depends on measuring conventions.

No, they don’t represent realities. They represent abstractions. And while we may choose at our leisure, the choices are not all equal. Some work far better than others. So we aren’t discussing truths about realities; we are discussing pragmatics about abstractions.

Is that the whole story? Physics references dimensionless quantities. As well, I can choose between Celsius and Fahrenheit, but it is not legitimate to speak of one million degrees below zero in either scale.

More generally, all measuring conventions may be regarded as ratios, which I think is a more suggestive approach.

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In special relativity:

The first statement is correct, you can switch between ASC and ESC at your convenience.

The second statement is wrong. Being able to choose ASC/ESC/or the literally infinite other conventions on the synchronicity has nothing to do with the space time geometry of the universe.

Further, as I said before,

OK. I did read your prior reply previously, and found the reference to GR interesting. I thought we could use special relativity for at least for an idealized flat non inertial frame. Is there anywhere I can find a discussion or paper specific to GR and Lisle’s proposal?

Why would the two way speed of light, which is not disputed by Lisle, be a property of the universe, but the one way speed of light not be a property of the universe? In ESC, the ratio of the two way speed to the one way speed is assumed to be 1:1. Is consideration of the ratio of light speed in respect to direction nonsense, or is there a convention adopted by nature such as GR? Is it even proper to speak of GR as a convention?

Correct. This means that SR is only valid in a small patch of spacetime close to an observer, so one cannot talk about cosmology or the age of the Universe using SR. If it is anything, the Universe is large.

Not specific to Lisle’s proposal. Lisle is not a member of the physics community and does not publish his results in mainstream physics journal, so no physicists write discussions about his proposal. The vast majority of secular physicists don’t even know of Lisle’s proposal.

If you are interested in the synchronicity convention in general, including its fate in GR, you can read: Significance -- Conventionality of Simultaneity

The author of that article is John Norton, a well respected philosopher of physics. You can find the answer to all the questions (except the last one) in your second paragraph there.


Of course that is legitimate. It just doesn’t happen to fit anything. Concern about what fits is pragmatics at work.

Conventions are social agreements. Perhaps you didn’t express your point well.

You are investigating Lisle’s ASC and time conventions in general. In the end, here is all you need to know as far as how all of it it impacts our Universe:

You will not be able to “beat” Lisle in his claim of an infinite one-way speed of light, though you should try. You will learn a lot in the process. [However] In the end, you will say with certainty, “He definitely got it wrong regarding the age the Universe. He never should have tried to impose his idea on a young Universe model.” But in all your reading, don’t miss the discussion here


Well, this week has been quite a journey. I fully appreciate that there is much discussion to be had pertaining to the outcomes of ASC, and that GR may render some of this moot. I’m just focused on the ramifications of ASC to my now refuted original posts concerning the speed of light and gravitational waves, so this thread does not get too open ended.

Norton’s article was very illuminating. The pertinent take away in the context of this discussion is that I must concede Lisle is actually representing scientific thinking faithfully as concerns the speed of light in special relativity. I’m coming around to this, but there are some consolations from the article. [I will quote for those who have not read the link]. I can tent with the “relativity of simultaneity” camp which
asserts that judgments of the simultaneity of distant events must change as we move between inertial frames of reference. However it presumes that within a single inertial frame there is one correct judgment to be made.
This is in contrast to the “conventionality of simultaneity” which asserts
In the same frame of reference, one person may assign relations of simultaneity one way; another person may do it differently. Within some limits, neither is factually wrong, according to the conventionality thesis, for there is no unique fact of simultaneity in the world.
Neither position enjoys empirical validation, so choose by inclination.

These two positions are loosely correlated but not identical to the realist, literal account of the world view, vs antirealist view, where all that matters is what we observe.

Now this is where I still find Lisle’s ASC to be at least awkward at the premise. When Lisle states “I will show that the one-way speed of light is conventional. It is something that is stipulated by us, and is not an independent measurable property of the universe”, that statement has him appealing to the “conventionality of simultaneity”. He is careful to phrase that the Bible “uses” the ASC convention. But near the bottom of his article he transitions from ASC convention to ASC model, where he states the ”ASC model implies that all regions of the universe have aged only a few thousand years as we now see them”. There, he has advanced a realist, non-conventionalist viewpoint, namely that conventions which imply an age greater than six thousand years are to be excluded, not excepting the ESC.

How does Einstein’s famous equation E=mc^2 fit into this? If the one way speed of light is infinite, wouldn’t this mean a Sun’s energy output would become infinite? Or is the equation wrong?

I think where c shows up in scientific formulas, that its value is just taken as the average speed of light. Offhand, I can’t think of an equation that doesn’t have a relativistic formulation. I also wonder how atomic absorption and emission energies work under various transforms, but I would suppose that the same reasoning which explains frequency of light under the transform would apply here. These “c” dependencies have been around for a while, and I expect they have been all dealt with in regards to the speed of light. I’m still being schooled on moving clocks.

What does it mean that distant star light is infinite? The sun is not distant to us, but it is to another star in another galaxy, so what is the speed of light from our sun as it passes the Earth on the way to the distant galaxy?

From Lisle
Under ASC, the speed of light as a function of direction relative to the observer (θ) is given by cθ = c/(1-cos(θ)), where θ = 0 indicates the direction directly toward the observer.

Hey, it’s not my theory.

The average between infinite and 3E8 m/s is infinite. Therefore, the Sun should be putting out infinite amounts of energy per unit mass.

Also, c is not an average speed. It is THE speed of light in a vacuum.

If the speed of light is infinite then it will always have infinite frequency. I would assume that an atom absorbing a photon of light with infinite frequency would be obliterated.

c = wavelength x frequency

True I expressed that a little informally. Under ASC, if you take the two way elapsed time of reflected light, and divide into the distance, that is an average of t1=zero and t2=1/2c * one way distance.

That was the position I started with, but there is no empirical measurement of the one way speed of light. Read PdotdQ posts.

Infinities are always a problem in physics, and that is a liability for Lisle. My belief is that the one and two way speed of light is identical, but that has not been proven.

As I have said in other posts, I’m a physics hobbyist at best. As far as I can see, the speed of light has to be less than infinite in order for any matter to exist in the universe. Either that, or all our equations in physics are wrong.

Not really the case. c is still c under ESC, ASC or many other conventions. Read the link below, suggested by PdotdQ. This whole issue does not lend well to a quick study, but I thought this was a pretty accessible article.
The Conventionality of Simultaneity

35 posts were split to a new topic: General questions on light and special relativity