Is One Way Speed of Light Problem For Special Relativity???
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- เผยแพร่เมื่อ 30 พ.ย. 2023
- In these days the speed of light seems as a very precisely measured number. But every measurement done to this day was only able to measure a round trip rather than a one-way speed of light.
Although there is no reason to think the speed of light should differ depending on the direction there is also no reason to think it should be the same.
The question is: Is it a problem for special relativity due to its light postulate?
The channel @dialectphilosophy thinks that due to this fact we can restore an absolutness of space but what does it mean? Let's find out in this video :)
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Hey Lukas! Your videos continue to impress us - and we want to say it’s extremely refreshing to see someone on TH-cam approach these sort of topics with a rigor and clarity of thought that doesn’t shy away from nuances. Plus, your love and enthusiasm for the topics at hand readily shines through, making your videos an enjoyable viewing experience, even when one may struggle to follow the math 🙃
You tackle the one-way problem quite deftly here, fleshing out numerous details we wish we’d been able to address ourselves, and doing so with an approach that is thoughtful and well-balanced. Indeed, we are very glad you made this video. If we had to make a quibble with it, it would be in your assertion that the one-way-speed-of-light problem is “well known”! We certainly weren’t aware of its implications until recently, and in the past our viewers gave us a lot of flak for saying that the constancy of speed of light was an “axiom”, decrying that it was actually proven fact.
To us the issue is perhaps not that the problem is not well-known (Veritasium certainly spot-lighted it) but that most people don’t realize that the entire symmetry of observer’s seeing each other’s clocks/lengths ticking slowing/contracting is a consequence of one-way light speed isotropy, not two-way light speed constancy. (Time dilation and length contraction are NOT a consequence of one-way isotropy however, as they must be retained in some form in either a relativistic framework or an absolutist ether view).
Moreover, we are told the basis for rejecting an ether theory is that we cannot empirically detect any such ether. But by that criteria, we would also be forced to reject Special Relativity, because there is no way to empirically detect one-way light speed isotropy. The invariance of the laws of physics meanwhile also follows from one-way light speed isotropy, since we’d have to change up how we express Maxwell’s equations if we abandoned it. (Indeed, one might wonder why we would expect reality to conform to how we wish to most simply express it…)
Currently our philosophy stance is that at the end of day, a theory is going to have to posit something that is unobservable. The question then becomes, do we stand to gain anything by once again adopting an absolute (albeit unobservable) simultaneity? We’ll be exploring that topic in upcoming videos.
Hope your channel continues to grow and gain exposure, as TH-cam needs more thinkers like you! Additionally, regarding your request for Einstein’s remarks on absolute motion, they can be found in this 1918 work “Dialogue about objections to the theory of relativity” - there’s a link to it in our Einstein Twin Paradox video.
There has been countless experiment about Aether. About its density, its viscosity, about light transport in moving aether, and many more. Not a single thing ever managed to detect aether, directly or indirectly. As for relativity, yes, there's no way to detect one way speed of light. But possible discripency in the speed of light is very well detectable in one way light path. And we've never seen that, did we? How that puts Special Relativity on the same footing as Aether theories?
Also, the one way speed of light with slow speed sync has also been done, and that result is also more consistent with light speed isotropy. Care to explain how that happened? Care to say what that means for your proposition?
I hope you'll answer. That is if you have the honesty or conviction to do so.
Not to mention, something as fundamental as the existance of an absolute reference frame should be detectable in every physical experiment. Which, again, has never been detected, directly or indirectly.
@@aniksamiurrahman6365so light travels through a magical nothingness void and also magically alters its behavior depending on who’s observing it? How is that science?
There is NO way to detect any discrepancy in one-way light speed, and slow speed sync doesn’t make a difference. Countless experiments have already proven that. Wow, it’s like you didn’t even watch Lukas’ video, or any of the other ones 🤦♂️
@@se7964 I've seen and pondered on both video. Its dialect whose saying that light changes its behavior arbitarily on observer. Its him who's argument dpeneds on different observer having different anisotropy factor. So its him talking BS.
As per, light travelling through void - it's an observed fact. If you have problem with observed fact, go do religion, don't come to science. In science emperical facts reigns supreme. its your magical aether that never been observed. Like never, directly or indirectly. That makes it imaginary.
@@se7964 "There is NO way to detect any discrepancy in one-way light speed"
Is it? If such is the case, then sunrise (when earth surface is going towards the sun) will seem faster than sunset (when earth surface is moving away from the sun). That, that's right there is a simple experiment to detect if the speed of light depends on the speed of the source or observer.
"slow speed sync doesn’t make a difference" The one way measurement with slow speed sync. give a value very close to two way speed of light. In fact the difference is exactly as if there's time dilation. Explain how it makes no difference you illeterate, explain how it doesn't. Or just FO.
The main benefit of Dialect's view of things is that a variable anisotropy restores sanity to the concept of simultaneity. In my opinion, this is the critical benefit to using variable anisotropy factors. Yes, somebody has to declare a master reference frame (which could be anywhere). There are experiments that suggest there is perhaps such a frame associated with the cosmic microwave background radiation so maybe choose that but, yes, traditional special relativity is not overturned by these ideas and the fact the GPS works so well is the best proof that scientists and engineers understands how to agree on simultaneity, position, and the speed of light.
I thought that point of that channel was the talk in circles so you don’t figure out it’s just ether 2.0 with that video essay clown. Science is not metaphysics. Science will never complete you that is not. It’s job.
@@MikeTooleK9Sok, now try again but less salty and more intelligible
The main problem with Dialect's view is that, things he claims are undetectable in any experiment - directly or indirectly. For the sanity thing, that's a "feelings". Someone else could very well "feel" the exact opposite thing.
I got one more problem with Dialect. Look carefully and his arguments just shuns the mistakes and incompleteness in them. And if you ask in the comment, he'll never answer - like a true Charlatan.
@@thenonacademyI don’t think it’s salty, I think it’s an apt response to a guy who acts so incredibly condescending, and is so arrogant despite being driven by the idea that hard to comprehend ideas must be false. In one of his video descriptions he talks about how he “scientific mysticism” because apparently the ideas of relativity are mysticism ?
If the speed of light was anisotropic, it would result in the observation of an anisotropic universe. That has not been observed.
If there is no universal zero velocity, it would result in an anisotropic evolution of the universe. We haven't observed that either.
I was waiting for your reaction to the last dialect video and here it is!! Thanks :)
I would also like to respond to his time dilatation video but I don't want to be a youtube debunker channel :D
@@lukasrafajpps yeah, you're right on that. It would be nicer to find your own path of videos. At first I didn't like the debunking videos of him (dialect) but now with his other videos you can see a trend and he is giving his own proposal not just rambling about what others do wrong.
@@lukasrafajppsyou don’t need a video to debunk him, a single comment will do.
@@lukasrafajpps I'm so curious what your issue is with the time dilation video!
Have you read any of Harvey Brown's work on dynamical relativity? I haven't myself, but he's a serious physicist and as far as I can tell, most or all of Dialect's ideas come from his work. However annoying Dialect's style is (and it is--although I do think he has good pedagogical and excellent visualization skills), I don't think he's just presenting crackpot ideas, though they are minoritarian ideas.
Thank you for making these videos! I appreciate them a lot.
Best video on this topic that I have seen in a long long time. Most of these channels shun the use of some simple math, but you don't and that makes all the difference.
Videos from the other channel are basically dedicated at proving there is an aether. The funny thing is that Einstein himself was NOT against the aether. He actually argued that there is a natural equivalent to the aether in the General Relativity which is the background metric (ignoring local massive objects) generated by all the masses in the Universe.
Perfect job as always!
11:05 Remember the Michelson-Morley experiment trying to measure the aether?
Special Relativity is a simple theory of hyperbolic perspective which is also true, and it is amazing that anyone should have any difficulty with it. If we meet a challenge to this theory, then try converting it to a challenge to the theory of elliptical perspective. The Earth is really shaped liked a rugby ball, but our rulers shrink or expand as we rotate them to create the illusion that it is round. Herdthink geographers are conspiring to cover this up.
I view the anisotropy of c the _exact_ same as the ability to chose a convenient reference frame. It is a free parameter we can chose to make the math simpler. Having a particular frame where k=0 significantly increases the math overhead for everyone else and is completely unnecessary. But it can be done. Like you can do simple harmonic motion in rotating cylindrical coordinates if you really want to.
It doesn't change the physics, it just makes your life more difficult.
Calling it a loophole is like saying inertial forces are a loophole to Newtonian physics. It's an artifact of a choice of coordinates, nothing more.
that is true
@@lukasrafajpps Clocks have nothing to do with time and these non sentient devices do not measure time. Can anyone use an unwound clock showing the relativity issue presented in this video? Also, this is all futile until mankind HAS the definition of time. Without it talking about time is sensless. The two way checking of the speed of light must have the variable of acceleration. Light accelerates when photons detach themselves from the source of light. NOTHING happens in zero moment. One cannot divide anything by zero ''seconds''. Seconds are in quotation marks because it is a sensless unit. And all this breaks down to nothing by just turning LIGHT OFF. In space void of light no relativity would even be fathomable. Light must have a medium to propagate.
I agree with you about the math. As I understand Dialect, he's saying it's a loophole for our interpretation of the deeper reality under the math, not a loophole in any other sense. Special relativity asks us to give up on the idea that simultenaity means anything, anisotropy of c allows us to rescue simultenaity. To me that is a huge plus. It's nice when theories match our intuitions for the world, or our abilitly to comprehend them. Sometimes theories won't do so, but when one interpretation matches intuitions about the world and the other doesn't, I don't see why we wouldn't prefer the intuitive, sensical one.
@@erinm9445 You can save simultaneity by saying some particular, _arbitrary_ , frame is correct about it and everyone else is wrong because of a property of the speed of light. Rather than saying everyone is equally correct because of a property of the speed of light. This lets us save the principle of relativity in a very simple way, which I think is a bigger deal. (plus we like symmetry)
Similarly epicycles let us save the intuition that the earth is the center of the solar system. That is a perfectly valid description and makes intuitive sense. But choosing the earth as the center is arbitrary. And if you look at the physics it makes more sense to describe the solar system as heliocentric by default and chose other coordinates when convenient.
It's a choice, and not a terribly profound one. Einstein chose the one that is "the least arbitrary". If someone wants to choose another, they shouldn't draw it up as some huge revelation but rather simply say why they chose some particular coordinates for some particular problem.
@@erinm9445 it's not just simultaneity that at can be restored. It's absolute space and time, which is why it's a "loop hole" to relativity even though we are describing the exact same physics.
Thanks man, great video! 🎉
Move both clocks halfway. What position is time dilation calculated relative to? Is there an absolute position and if not how do you know which clock is moving and which not.
can we anisotropically travel faster than the speed of light? If I can move from point A to point B with infinite speed but to move from point B to A I'd be forced to travel at [c] that would be okay right? no infractions against causality would happen.
I skipped Veritasium video, as I preferred a less click bait approach, thanks! Good presentation
Why not take two synchronised clocks next to each other, and move them BOTH in opposite directions to a predetermined distance. They should remain synchronised, and thus able to measure a true c
the time dilatation apply differently in both directions if the speed of light is anizotropic
Please correct me if I'm wrong, but there seems to be a third way of measuring the one-way speed of light that should eliminate the problems with clock synchronization posed by moving a clock from one location to the other as well as that posed by the possible anisotropy of the speed of light. Wondering why this scenario hasn't been addressed in this video.
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An anisotropic speed of light would have wider implications for cosmology as you would have to reconcile the hubble constant by a similar factor, giving rise to there being a center of the universe.
I have an idea that can be used to simulate an FTL signal but also might be able to measure the one way speed of light.
I have an idea for an experiment that would simulate FTL and how different observers would have disagreement over the sequence of events, one would see the events appear to go backward in time. I think you could make a great video showing what would happen and it would be very illuminating.
Take a track say it goes North South and along the track are LEDs. At each end of the track there is an observer. Let’s call the end of the track which illuminates first, side A, and where the last LED is energized as side B. Now imagine you have a computer with a signal channel per LED and each LED had its own conductor wired in parallel. The computer output channels are set up such that when the first LED in the chain near Observer A is energized the next channel energizes in a time span that would be FTL if the circuit were in series. So if it would take one microsecond for a causal signal to reach the next LED in the sequence, then the channel for the second LED would send its signal at say .5 microseconds simulating an FTL signal.
Say the computer emits a signal that says “Now” when the first LED is energized and emits a “Done” signal when the last LED energizes to each observer. What would happen for both observers?
Observer A would see the correct sequence as the first LED is closest to Observer.
Observer B would see the “Now” signal so he knows at that moment the signal arrived at the first LED but Observer B doesn’t see any LEDs energize because of the speed of light hasn't reached him yet. When the computer issues the “Done” signal at that point Observer B would see the last LED energize first and the the second to last and so on. Observer B would see the chain of LEDs appear to go backwards moving from side B to A but Observer A would see the light chain move in the correct order, from A to B.
So Observer B would say that the last LED lit up first and then second to last and so on, completely backwards from what observer A sees. Someone who is flying towards you FTL, you'd see them appear in front of you first and then a copy image would appear to move backwards according to this experiment outcome.
Thanks for these videos. I'm not a physicist, it was a field I liked since my school days, your explanations and explanations of reasoning are amazing, and I liked your attempts to try and see if you can attack those theories, and what happens if you do, what are the attack vectors etc. I think physics and science needs more people like you than taking everything as unquestionable gospel. No-one questioned relativity, but you gave really good examples and explanations as to why this is so, you even managed to make complicated math seem simple, all without patronizing your viewers as if they're idiots, Bill Nye style. Had physics had more people with these skills, we might have had more physicists. Thank you and Subscribed.
I also have a question. I like relativity, and I quite understand it for a layman, however I'm not really a fan of magic constants or magic properties (like aether in the case of Einstein and your video, or even the widely accepted dark matter etc). When I see one, despite all saying, well this is how it is, internal alarm bells ring in me saying this is wrong. So, you can imagine I kinda have issues with c, the speed of light. First of, I think c as speed of light is a misnomer, as it's not a speed of light at all, but the maximum rate of information propagation. It applies to anything and everything, not just light. It even applies to gravity, which we kinda don't quite understand yet. Then I realized, the force of gravity decays through distance. Electromagnetic forces also decay through distance. Not light it seems. Well, why not? Are there clues out there that light could also decay through distance? Yes. Redshift. But physicists interpreted this as it's not light decaying through distance, it's actually objects moving faster the further away they are. That's silly I think. Why would the universe accelerate outwards? There is no reason for this, not even a big bang is reason enough for this acceleration. If you see it as light decaying through distance though, it explains away the universe accelerated expansion. So I concluded, one can theorize for everything decaying through distance and this could be a fact. Then I was trying to connect the pieces, gravity is affecting the geometry of spacetime, and this also explains its existence but also its decay through distance. What about everything else? Then I stumbled upon a brilliant youtube video, theorizing about the possible geometry of spacetime, what if spacetime was actually hyperbolic? We are unable to detect this in the same way we cannot tell the earth is round if we are at its surface. Although, if spacetime is hyperbolic, it would seem as if objects are accelerating the further away you look. It would explain the decay of everything through distance, including that of light, and most importantly, there would be no c. No real actual limit on the rate of information propagation, it'd actually be instant, this limit c only appears as you account for the geometry of the medium in which information propagates, spacetime. Everything made sense to me after this video. If you would like to reply, I'll see if I can find this video again, and maybe you could make your own video reaction to this video. I'd like to see this. Thanks.
PS: Ok, I just realized one more relation, scientists describe gravity as a weak force, while electromagnetism is a strong force. However, the area of effect of gravity is vastly greater than that of electromagnetism, and if you wanna measure them in regards to their area of effect, or rate of decay as I call it, gravity actually has a slow rate of decay compared to electromagnetism, and this would make gravity as a strong force in this regard, and electromagnetism as weak. Is there an actual inverse relation? An inverse relation to the strength of a force vs its rate of decay? Am I onto something or am I seeing things? Tell me I'm about to unify those forces. LOL (or completely disappoint me)
PS2: You do the math, I'll share that physics nobel. LOL 😃
the invers square relation between the strengh of elmag field or gravity field is nothing misterious. Actually it make the most sense considering we are living ina spatially 3D universe.
If you consider a flux of water for example comming from a spherical body to every direction, this flux would decay also with second power in radius and it is because the survace area of a sphere is dependend on the second power of the radius and if you want to conserver the amount of water in each layer then the density of that water must decrease with second power.
This also apply for a light comming from a sperical body. the number of photons in each layer must be conserved and therefore the photon density decreases with second power of radius. Otherwise the Sun would burn the ..... out of us :D
If we lived in spatially 4D universe then this decreasement would be with third power and so on.
@@lukasrafajpps Thank you for replying! :-) I understand this, and what you say makes sense, a 4D universe would cause a 3rd power in decrement and so on. Still, I was not quite referring to this, this was a 2nd argument, my 1st had to do with the geometry of spacetime, the 2nd was about the relation to the forces. I was referring to the inverse relation between the strength of a force, and its rate of decrement, as in, the stronger the force the higher its rate of decrement, and vice versa. The reason gravity affects objects in the macrocosm, is exactly because it is a weak force. Had gravity been a strong force, its rate of decrement would be such that would have had no effect in the macrocosm. Isn't this a relation that explains the reason gravity seems "different" from the other forces? It's not at all really, and it could very well be a strong force. In this case the universe as we know it, wouldn't exist obviously because gravity would have no effect in the macrocosm. Or you could have a theoretical universe with a weak electromagnetic forces, in which case, atoms wouldn't form as we know them, but those electromagnetic forces being weak, would have a slow rate of decrement, just like gravity, probably affecting the microcosm in distances of hundreds or thousands of km. What I am trying to say is that all forces have exactly the same properties, they are not at all different, they appear as such because they have different values on those properties. It is those specific values that allowed for the universe to exist as we know it, had any of those forces had a slightly different value in any of their common properties things would be different. And this way, gravity is really not at all different from electromagnetism. It shares the same properties. If you go further with this, you could unite those forces, as they are exactly the same thing, it's the same thing we observe, the same thing with different values in its properties. There are no different forces, it's the same thing. Going a step even further, there could be no specific values either. A force could have all values, but we only observe the effects of it on certain values, as other values have no effect. It's one force, affecting its environment like a wave. ie. the same force which holds the atom together also holds the planets together. Suppose an elementary particle emits this force like a diminishing wave, and this force has different values. Only a certain range of high values will affect an electron, the rest weak values of this same force would go on to become gravity. You can even take this further and say that it's not the particle that emits this force, but its presence on spacetime causes this, it's a property of spacetime, just like we observe in the macrocosm, and unite everything. Now the reason for the decrement of this force, is another matter, that was my 1st argument, the reason for a signal's decrement is the geometry of spacetime. As in, there is no real decrement in theory, it happens so, because of its geometry. And it could be hyperbolic. Had our 3D space been flat, we would observe no decrement in anything, everything would be instant. Forces would apply forever at the same strength no matter the distance. Anyway, I think all this is quite some material for thought, I do not mind being wrong here or there or everywhere, but to be honest, it just makes sense to me. But as I said, I am no physicist. So, I thought of giving this to you in case there is something to it, and in any case, even if not, there is no harm in devising hypothesis. At least all these, whether right or wrong, I think are more grounded and reasonable than those multiverse theories that circulate, or things that are out of the universe's scope. Anyway, I will try to find that video explaining hyperbolic space that kinda made sense for my 1st argument. It might take me a while and hope I find it, I seen it a long time ago. In any case, that's sort of my ideas about the universe, they kinda make sense to me, I hope they are somehow useful. At least I tried. :-)
Is there a way of knowing the isotropy of the speed of light without measuring a one way distance? You only have to compare two speeds and see if they are the same not really know what their values are like in michelson moreley.
Could one not synchronise two clocks (and light sensors) in one place and then move each of them in opposite directions by a defined amount? Then one sends two light pulses at the same time, one to each clock, and finally compares the times at which the clocks received the time signals. Why wouldn't this enable a comparison of light speed in two different directions?
There are several observations that show the speed of light is the same in all directions. There are technologies that work that are based on this assumption and that would not work otherwise!
1. GPS
2. Phased array antennas
3. Standing waves between a microwave source and reflector - this can be used to measure wavelength and calculate C. If the speed was not the same in the two directions sinusoidal standing waves would not form.
One of the most insightful and informative video on this topic available for free 🙂
I am glad it was helpful! :)
when separating the two clocks, to keep them in sync, how about: send a light pulse from A to B every 1 second. At clock B ignore the "time" it "took" to get there, ignore the time between pulses at B, just count the number of pulses. Clock B moving at 99.9% light speed will still "see" the correct # of pulses and can just keep setting it's clock to zero seconds + the number of pulses, this would limit the uncertainty of synchronization at B to the pulse frequency, so to get more accurate, send pulses more frequently. when it's gone far enough and decelerated, can't clock B know when it's returned to rest with respect to clock A by spotting when the inbound pulses are coming at the exact same shape and frequency as pulses generated by it's own time-keeping mechanism?
I'm amazed by these demonstrations and I cannot appreciate enough the great work done here, the first thought that occurred to me had to be the inception of field theory, and the maxwellian derivation of speed of propagation of electromagnetic fields. since a definite wave speed from a wave theory did not suggest a parameter or any sort of anisotropy, the problem of the one way measurement of speed of light did not have to be a kinematical issue, since the wave theory predicts an isotropic value of propagation in all directions, the wave must thus travel by this speed in all moments, so shouldn't this be a wave problem and not a kinematical one, anyway if there's more that I should know regarding the possibilty of emergence of this anisotropy in the motion of light, I'm open to full understanding.
You can tell that light travels at the same speed in all directions by observing something like the Cherenkov radiation in water cooled nuclear reactors.
If the speed of light were different in a certain direction, it would have an observable effect on the radiation emitted.
Also a substance's light refractive index is not dependent on the direction light is moving through the medium. We know this by observation.
Why are you using deltaT = 10m instead of 10min at 4:23? It evokes a unit of distance instead of time. Very informative video by the way.
true, my fault :(
Isn't Rømer's determination of the speed of light in 1676 using the moons of Jupiter as a clock, a one-way measurement? The speed of light = 1 astronomical unit /11 minutes (not really accurate, but nevertheless a demonstration of isotropic speed of light). If the speed of light were actually anisotropic, it would also play havoc with the orbits of the planets.
Romer used himself as a clock, and moved himself, the clock, closer/further to the source of the light, so while he observed a one way trip, like looking at a Pulsar, he moved his clock.
Does "speed" mean relative to an inertial frame of reference, or does "speed" mean invariant with respect to the frame of reference?
What if the two clocks are moved simultaneously in opposite directions at the same speed? Wouldn’t that retain the synchronicity?
the time dilatation apply differently in both directions if the speed of light is anizotropic
What if you synchronize the clocks midway, and make them travel the same distance with same speed in opposite directions, do the pulse measurement then bring them back midway to compare results. Would this work?
I think the perspective shared by Dialect is important, because the way relativity is taught, you can be led to the assumption that constructing a simulation of our universe using absolute space is impossible. That’s at least the impression I got, and caused a lot of confusion as I tried to work through “well what if I tried to get the effects of relativity in absolute space.. what will stop me.. what am I missing?”
It’s not common knowledge that you can’t measure the two way speed of light. At least before the Veritasium video. I’ve never seen it covered up to and including a university level physics course.
I’m curious to see what point Dialect is working towards.
I suspect that working with alternative perspectives of space time could become important to make further progress in our understanding of physics, so I think more of those kinds of perspectives is great.
What if there was somebody equidistance between two clocks? The delay should be the same for each, if they're not at the same time they'll know they're not synchronised.
It seems to me that a better way to synchronize clocks is to use mechanically symmetrical separation of identically constructed clocks. This wouldn't work for astronomical measurements, but I think it would work for terrestrial measurements. That way, light doesn't come into the synchronization. I think that practically this idea is routinely used by the GPS.
Well there is place in space-time called photon sphere near Black Hole. The light shot forward will return to your back.
With Michelson-Morley experiment: what if movement of eater is in (let me say it) time direction? Is there analogue of M-M exp. with time crystals?
And about the last one(frame of absolut rest): sphere of detectors, laser at center, detection of energy(wawelength, frequency) in each direction. For absolut rest frame they are equal everywhere. No?
I really enjoy your videos! I don’t understand the can’t measure the single direction of the speed of light as seems to be done all the time in microwave systems or anywhere where we are sensitve to wavelengths of electromagnetic propagation. Any optics theory just falls apart and I dare say that instrumentation of a particle accelerator would be of little use is particles where changing velocity around a synchrotron.
What if we start with two clocks and they each move in the opposite directions from the starting point? Then the time dilation will be identical
it would be identical with isotropic light behavior, if the light behavior is anisotropic then the time dilation experienced would differ
If the measured speed of light actually depended on relative motion you would experience some wierd outcomes. Eg, if a distant object that was being observed suddenly started moving towards the observer, the light would catch up to and pass light emitted earlier and a clock on that object would appear to run backwards.
The speed of sound is anisotropic when you are in motion. Imagine that the atmosphere was uniformly dense and perfectly still. Would moving fast allow sounds from an object's past to reach you before sounds from its future? No, of course not. Because the sound waves are actually moving at the same speed through the background medium, they're just moving at different speeds *relative to you*, depending on your speed.
@@erinm9445 but no one is claiming that this causes us to see the future, it's just that we would no longer see events in the same order. And that does in fact happen with sound, if an object moves at or above mach I will hear sounds emitted from it at a later point before those emitted earlier. I mean this is literally part of everyday experience if you've ever had a fighter jet pass over you, you hear the characteristic sonic boom as sound from when it passed over you and sound emitted earlier arrives at the same time, and then a rumbling afterwards as more pilled up soundwaves reach you. If light had an anisottropic speed like sound we would expect something similar where light bunches up and reaches us at the same time but that clearly doesn't happen, we either see light arriving in order or at the same time due to time dilation, we never see light arriving out of order in the way that sound does.
@@hedgehog3180 Not necessarily. Remember we can't ever move at 'Mach 1' in the light scenario, because that would be 'c'. However, we can already 'see the future' in a sense, with or without the sound analogy. If a planet 100 light years away emits light, but then 1 year later a planet 5 light years away emits light, technically the latter is 'from the future' but we still receive that light first, because it's closer.
Instead of a single light pulse, can you measure the one way speed of light by sending two pulses of light to the traveling clock with a delay between the pulses?
The speed of light depends on the amount of gravity in the vicinity. Everyone should already know this. The speed of light isn't constant since the measures of time and distance used to measure speed are not constant. In fact the changes in time and distance exaggerate the differences in the speed of light.
Why not just stand directly between the points and send a light pule in both directions to synchronize the clocks? Then they're perfectly synced and you can perform the experiment
That only works if the light moves at the same speed in both directions. Which is exactly what you are trying to test for in the first place. LOL The point of measuring the one way speed of light is to see if the universe itself has a master reference frame. That would mean that light speed would be different if moving in the same direction of the earth or the opposite direction. Since the speed of light is so fast (186,000 miles per second) the difference in speed would be very small. On the order of 18.61111 miles per second or something ( I did the math at one point LOL) It would be very hard to detect within a reasonable margin of error if we actually had a method..... which we don't...... because to do so would require faster than light communication. LOL
@@robertplunkettschesslab so do the experiment and then rotate it 90 degrees and do it again lol
@@DanOC1991 then how do you verify the results? LOL You'd have to bring all the synchronized clocks back together to compare. Then they would all change with the exact ratios of time dilation over the distance traveled and You'd have nothing again. You can't communicate the results to each other because again all communications would travel at light speed and You'd have no way of knowing which direction the speed was different because the results would need to be communicated in BOTH directions. So yes..... you would get a result..... but you could not verify that result with each other or a third party without nullifying the result. If you can communicate the result faster than light there are all kinds of methods.
@@DanOC1991 I once thought it was possible to do it by measuring the speed in the backdrop of a medium. So you could use the one way speed of light through a vacuum to measure the speed of light against a medium..... because light also changes it's own speed through mediums.... You could try sending light in two directions through mediums where it travels at slower speeds and then measure that speed by communicating the results with light speed through a vacuum...... but that still would only give you the answer for the one way speed of light through a medium......and this type of experiment would have it's own problems. LOL it's a very hard question to answer.
My feeling about this is "Why WOULD the speed be different in the two directions?" There should be no preferred direction - if we allow for those speeds to vary, that is assuming that the universe is not isotropic.
Also, I've never considered the "light postulate" necessary. Once you have the first postulate, invariant laws, well, Maxwell's equations are laws, and they predict the speed of light. So by postulate one the speed of light has to be the same for all observers.
Finally, who cares? Any dependence of the speed of light on direction can't possibly affect any of our predictions. If it could, we'd have a way to measure it. So the very fact that we have no way of measuring it means that it has no impact on us, so we can ignore the whole business.
The one way speed of light has been measured and it is c. This was done by transmitting a radio wave from one dipole antenna to another dipole antenna, where both the transmitted signal and the received signal are measure by one oscilloscope (ie. one clock). The orientation of the 2 antennas were pointed in many directions and experiment was repeated many times over months. But the experiment showed something unexpected. It showed that speed of light is instantaneous in the nearfield and reduces to the speed of light about 1 wavelength from the source. Since Relativity assumes light only propagates at speed c, and this has been shown to not be true especially in the nearfield of the source, then Relativity needs to be reanalyzed. Derivation of Relativity using instantaneous nearfield light shows that Relativity reduces to Galilean Relativity, and only in the farfield does it reduce to the speed of light c. This is because as c=infinity, the Relativistic gamma function becomes equal to one, causing the Lorentz transforms to reduce to the Galilean transforms. But using farfield fields yields the Lorentz transforms. But since time and space are real and can not depend on whether nearfield or farfield fields are used (i.e what frequency of light is used), then the effects of Relativity on time and space must be an optical illusion. Time and space are absolute as indicated by Galilean Relativity. When moving objects are observed using farfield electromagnetic fields then time can appear to dilate and space can appear contract, but the effects are not real and can be verified by using nearfield electromagnetic fields which will show time and space have not changed.
Since General Relativity is based on Special Relativity, then the effects of General Relativity on time and space must also be an optical illusion. So what is a better theory of gravity if General Relativity is wrong. It is well known that General Relativity reduces to Gravitoelectromaganetism for weak gravitational fields, which is all that we observe. Consequently Gravitoelectromagnetism predicts all known observed gravitational effects. But the difference is that Gravitoelectromagnetism is a field theory, whereas General Relativity is a geometric theory. Gravitoelectromagnetism assumes gravity is modeled by 4 equivalent Maxwell Equations as for Electromagnetism. The equations only differ in the constants used. Gravitoelectromagnetism is field theory of gravity and assumes there are both an Electric and Magnetic components of gravity. Just like for electromagnetic fields, changing magnetic fields create electric fields and visa versa. Gravitoelectromagnetism also assumes time and space are absolute and not flexible as General Relativity predicts. For more information see my short 15 min TH-cam presentation and the paper below it is based on. William D. Walker and Dag Stranneby, New Interpretation of Relativity, 2023. th-cam.com/video/sePdJ7vSQvQ/w-d-xo.html
Instantaneous propagation in the near field has been investigated using group and phase velocities of wave packets. It turns out that the phase velocity can exceed c over very short distances but any information carried by such wave packets, in the form of modulation of some sort, does not propagate faster than c. It is this that saves relativity. No need for pointless reevisions.
@@rogerphelps9939 In the antenna experiment mentioned, the phase speed, group speed, and information speed were observed to be Instantaneous in the nearfield and reduce to the speed of light c in the farfield. This is in complete contradiction to Relativity. See the paper and presentation for more information.
@@rogerphelps9939 We have just completed an experiment that proves conclusively that information can be propagated nearly instantaneously across space, in the nearfield of an electromagnetic pulse. The experiment consists of a ~30kV high voltage spark generator creating an electromagnetic pulse that propagated 1.5m to a detector. The leading edge of the transmitted pulse and the leading edge of the detected pulse were then compared using an oscilloscope and no time delay within the capability of the scope was observed, where 5ns is predicted if it had propagated at the light speed. The maximum uncertainty in the measurement was 1ns due to noise in the electronics. Since a pulse is digital information. This experiment proves information can be transmitted across space nearly instantaneously. The results is perfectly predicted by Maxwell equations, which yield a wave equation set equal to a source term. Analysis of this equation shows that the phase speed, group speed, and information speed are instantaneous in the nearfield and reduce to the speed of light in the farfield. Below is a link to see a preprint of the paper.
Electromagnetic pulse experiment paper: www.techrxiv.org/doi/full/10.36227/techrxiv.170862178.82175798/v1
TH-cam presentation of above arguments:
th-cam.com/video/sePdJ7vSQvQ/w-d-xo.html
More extensive paper for the above arguments:
William D. Walker and Dag Stranneby, A New Interpretation of Relativity, 2023:
vixra.org/abs/2309.0145
i think jwt can see the lack of medium light need to clone it self (might need to turn off most filter . ) on tv its like when not enough backlight led are present . In space , it will be like someone removed medium in the region . There should be a lot of those like huge amount
Part of the problem is that the speed of light is not a constant, vut loses approximately 4.6mm/s/year. Shown by the redshift from some of the furthest galaxies. But second, special relativity is wrong also. The frames of reference we are in is affected by the same gravity etc. we are not in separate universes that only contact each other when we come together. The twin paradox exists in the model due to the time assumption.
I believe the issue extends beyond solely the inability to measure the one-way speed of light. The fundamental issue lies in the fact that the one-way speed of any object is unmeasurable, as all speeds are contingent on the value of the one-way speed of light.
the only problem i got ? Newton resistance to change . But it does not seem newton resistance to change is considered with light by academia
Great Video, I really enjoyed it :-)
There is another problem with the video from dialect. The ansiotropic speed of light is limited to a lower limit of c/2. If it would be slower than that, the one way time would exceed the roundtrip time, and we would be able to measure it. Therefore, the idea of assigning different values of k does not work for observers moving faster that c/2 relative to the medium.
Let me know what you think about this argument.
Thanks again, Mads :-)
That is actually true, shame I missed this fact :-) Thanks
As Reichenbach and numerous others have pointed out, there is no lower or upper bounds to what we can assume the one-way speed of light to be, whilst the two-way speed remains constant.
As discussed in our video, if the one-way speed is slower in one direction, then it must compensate by being faster in the other direction. So if you fire a light beam and it travels at a snails pace relative to you, then once it reflects back and begins traveling in the opposite direction it must travel at an near infinite speed relative to you. This ensures the two-way speed is constant.
This of course doesn’t mean light speed is actually near zero or near infinite - the sensible interpretation is merely that you are traveling at nearly the speed of light in some ether-like frame.
@@dialectphilosophy From your answer it seems that you agree that the roundtrip time must remain constant. If we place a mirror on the moon the roundtrip time will be about 2 sec. If the oneway speed is below c/2 the signal will take more than 2 sec to reach the moon. Even if the return speed is infinite the total time will still exceed 2 sec in this case, and we would be able to measure it.
Veritasium exemplifies this as well th-cam.com/video/pTn6Ewhb27k/w-d-xo.html
@@dialectphilosophy Formulated in math: t2=t1+epsilon(t3-t1), with 0 < epsilon < 1 (as stated in the dialect video). Rearranging we get epsilon = (t2-t1)/(t3-t1) = (One way time)/(roundtrip time). If the one way distance is S, we can write t2=S/v, and t3=2S/c. If we pick the start time t1=0, and insert we get epsilon = Sc/(2Sv). In the upper limit where epsilon = 1, we then have v=c/2.
I highly value that you challenge the narrative. Please continue to do that. I also hope you will publish a correction to your video, if you end up agreeing to what I write here. Best regards Mads
@@thesparetimephysicist9462 As we have stated here and elsewhere to you already, the math of one-way light speed has been well formulated by multiple individuals across multiple points in history. Please consult the equations in our video, or check out the references listed in our description section for more.
light postulate(mine) once generated light does not move but clone it self in a spherical way via all valid medium within reach (most medium move)
We now have clocks precise down to 2.3*10^-18 seconds. We can measure one way trips to within that precision, can we not?
The speed of light can be calculated directly from the permeability and permittivity of the vacuum. Both of these values can be measured directly from simple experiment. Neither value is dependent on direction.
Maxwell's equations in their standard vector form is only valid in inertial, isotropic coordinates, so you have already assumed isotropic one-way speed of light in using them. If you change to another convention, the form of Maxwell's equations will change as well.
@@Argoneui I didnt use Maxwells equations.
I recently commented on another video that a synchronized measuring device could be sent to space with a program that continually adjusts the time so it stays in sync with the device on earth. This could be used to measure the speed of light when it's travelling away or toward the earth to see if there's any difference. I can't think of any reason this isn't possible.
but how you know how to keep the device synchronized if the time dilatation behaves differently in the speed of light is anizotropic?
@@lukasrafajpps If a time measuring device were sent into space, the path, direction and velocity would all be known in advance. Just as your video explained, the difference due to time dilation could be calculated and, therefore, adjusted for.
First postulate: Laws of physics are the same in every INERTIAL frame of reference. Accelerated frames have different laws of motion depending on acceleration.
But sir, as you've shown, in the one way speed of light with slow transport sync differens very little with the two way speed of light. Whether by the math in @8:39, this difference is proportional to distance. If anisotropy was real, wouldn't this difference have been a good experimental way to detect that? After all, light speed can't differ when we're trying to do slow speed vs light pulse syncronization.
question. If light has no motion at all. (humor me lets exclude mathemetic to keep argument sane) what did i just break . Not from academia toy list . But what would stop working properly in creation (non religiously) if i am right . There is no isotropy of anisotropy of speed of light
Start with both clocks at a central location, synchronize them, and then move them equal distances at equal velocity in opposite directions to the test distance.
lets try to measure an anisotropy with your experiment. In order to be an anisotropy in lightspeed, there must be a velocity of the whole system which we try to make a measurement to find an anisotropy. else everyone agrees both directions will be isotropic right ? imagine a train as always, if outside observer tells that the trains is not moving, there is not a difference in simultaneity right ? no need to restore sanity, no need to restore block universe to presentism. we can easily take the 1way speed of light as c and everyone agrees. when train starts to move compared to outside, this is when we need the one way measurement. And when we start the clocks at the mid train and move at the same time same velocity for someone inside the train cause the forward velocity is faster than the rear one according to the outside observer, creating the exactly same amount of de-sync forcing you to measure isotropy.
if you adjust the velocities of mid clocks equal not from the observer in train but from the outside observer, without touching them to the train at all, this results rear clock will reach to the end of the train and starts to move with the same speed as train where the front one reach much after that then reaching to the same speed as train. as in order to reach the front end of the train, mid clocks should have a larger speed than the train according to outside observer. and rear clock reaching the lower speed which is the train's speed much earlier causes its time will be less dilated during that duration where the front clock still going larger speed to catch the front, having more dilation. this cause front clock have less time compared to rear as always and create the same de-sync.
if you ask us to forget about trains and let clocks reach at the same time, this means as I stated at the beginning the system which we try to measure anisotropy is not moving at all according to outside observer, so there isn't any difference of simultaneity caused by that system and we already agreed the isotropy.
measuring 1way speed of light is important to measure anisotropy, if we all agree there isnt a cause for anisotropy such as equal velocities, 1 way speed measurement is not an achievement since the above problems causing it to be isotropic and preventing you to find a "proper" speed of the system you all agree that it is at rest. which is not exist, creating SR.
That is not how I would try to measure the one-directional speed light (if had the money to try). You would take 2 in-sync clocks, and 2 lasers, and leave the detector in the middle. You transport the clocks at the exact same speed in two directions. No need to re-sync (adjust) the clocks. Also, the more clocks pairs used and detectors left in the middle the more data you can accumulate as measurements. You repeat the pulses thousands and thousands of times for every setup of clock pairs and detectors. Calculate the mean distribution, the light speed will be that mean divided by 2.
By assuming that time dilation is the same in all directions you are already assuming that the speed of light is the same in all directions.
Time dilation is dependent on the speed of light and can not be used to determine a directional difference.
I do not see your point. Everything is assumed until measured. This is a way to actually measure the speed if you are careful in setting up the equipment and have the money to do so, for the expensive equipment. There is no reason to assume time dilation is real for certain, or that it will be different in 2 directions equidistant from the same starting point in the same gravimetric field. Also, energy fluctuating in a slower way as energy in the field gets more dense doesn't mean time dilation actually exists. It is more of an apparent thing than a feature of reality. Models of reality are not real; not reality. Also, there is no time particle to be found and measured. And, you cannot break off a piece of a field and analyze it either. The clocks are made of energy, everything is; and it is coupled to a field. IMHO the speed of light limit (causality) is more likely a field property than a discrete particle property. @@narfwhals7843
@@itopal63 The point is that time dilation is dependent on the speed of light. If the speed of light was different in two different directions, then time dilation would be different in the two different directions, in a way that would exactly cancel out the difference and make it all be measured at C. If C was half-speed in one direction, you'd get double the time dilation when you moved your clock in that direction, and so you would still measure the speed of light at c. This is an uncontrovercial fact among physicists.
Doesn't the frequency and the wavelength of the light determine the speed? Am I missing something stupid?
Rigorously synchronized clocks exist with the GPS positioning system. The GPS you carry with you all the time gives exactly the same tic as mine . We place these two clocks on two
locations on Earth at the same latitude and we measure the speed of light in both directions. Result: we report a small difference of light speed of c - v eastward and c + v westward relative to the surface of the Earth, v being the speed of rotation of the Earth's surface at that latitude. This does not work at or near the poles then. This experiment has been done. Ref: Paul Marmet, " The GPS and the Constant Velocity of Light". Conclusion: light is propagating through an ether -or whatever it can be called-, a then viscous gas which "sticks" at the surface of the Earth and less in altitude (refer to 1925 Miller experiments) and other celestial bodies as well. This is the best explanation.
The GPS uses a certain calibrating convention (The Einstein convention) but you can't say the clocks are truly synchronized. It can be the case that they are not synchronized in reality but due to the anisotropy of the speed of light you get precise measurements.
Yes, this is true, the GPS system uses some protocol to correct the drifts in order to synchronize all the clocks, this is the goal. Once done, you get all the required precision to carry out one way speed of light measurements. Paul Marmet was an accomplished researcher with a long list of published papers, we cannot doubt about the anisotropy of the measured speed of light and you just mentioned it! This means the speed of light is not the same in all directions and the measurements indeed yield c+v and c-v. This was also investigated by Stephan J.G. Gift. So we are in full agreement.
@@lukasrafajpps
I think Dialect’s argument makes more sense than special relativity. With media, it is more reasonable to create a reference frame with media than assuming each observer is the rest media as special relativity assumes. Without media, it is more reasonable to assume the reference frame is the emitter not the observer. Either way isotopic speed of light is better to describe the simultaneity of events happening around us. Einstein assumes nothing travels faster than light thus even if it happens differently at time it is fine since the observer will never know but there is many body reaction that will project the causality to us even if we cannot observe something directly.
Say a space craft flies at almost speed of light and shots back a cellphone every 1 second in its own time frame. The cellphones are stationary to us. What will we hear about the cellphone report the time inside the space craft? Now put the stars in the edge of our observable universe as the craft. See if the conclusions of the theory make sense.
Alain Aspect, the Nobel price of 2022 has the tool to generate an instantaneous transmission of the information with quantum entanglement pairs. Is that tool could be utilized in an experiment setup to mesure C in one direction?
Yes, thank you.
how any experiment can measure the change in the speed of light if they cannot measure the one way speed of light?
I don't understand. If something is one light year to the left and another is one light year to the left, then they are both one light year from me. Does talking about any other distance measurement even make sense?
That is the distance in your reference frame. Another observer may see a different distance and that distance makes just as much sense. That is length contraction.
In Relativity distances in space and time individually have no inherent value but are relative. The combined "Spacetime Interval" is something everyone agrees one, though.
@@narfwhals7843 but I thought the point being made is that we can't measure a difference in the first place. If it did become apparent in another frame wouldn't that make it measurable?
@@Jim-tv2tk I don't think I understand your point. How do you think this will enable you to tell a difference in the direction of the speed of light?
@@narfwhals7843 that's what I was saying. If it's fundamental undetectable then it can't exist. My take was that there isn't a way to prove if light is C in every direction.
Special relativity is always surprising & deep thinking always open new ideas & kind of think for eg measuring speed of light from our perspective we see the light moving from place to other (passing adistance in certain time )... But for the perspective of light itself the light is not moving because the length of the distance between the two places is contracted up to zero & consequently the time taken is also zero... (in reality it's zero because during the speed of light the time is frozen & the clock is not running)..... Also not only the distance between the two points the light will pass were contracted to zero BUT THE WHOLE UNIVERSE IS CONTRACTED TO SIZE ZERO FOR THE PERSPECTIVE OF THE LIGHT (of course moving with C speed)
One problem to me is special relativity has no ability to describe interactions between objects that is moving close to speed of light or faster than speed of light such as those in the unobservable universe that is leaving us. But they should have the same physics and chemistry as us just we see them freeze in our telescopes. They are not freeze to a observer in between and we can see the middle man moving with responses to those freezing universe.
Instead of one clock moving a slow velocity away from the stationary one, why not both move at the same velocity in opposite directions. Then same gamma thingy for both
no, the gamma thing is different, if it was the same then the velocity of light would have to be the same
The GPS system we ALL use is based on the one way speed of light and simple geometry of intersecting spheres.
That is ok. We just naturally chosed the easiest synchronization convention (Einstein's synchronization). However there is a freedom to chose it differently
Here's something about relativity to think about. Supposedly, if you were moving at a velocity close to light speed you would perceive everything outside of your frame as being contracted in your direction of motion. Some people will try to use that idea to explain muons reaching earth before they decay, suggesting that in the muon's frame the atmosphere would be contracted to about 1/10th its normal depth as perceived from the earth frame. Well, everything outside the moving frame being contracted is the same as the moving frame being lengthened, logically. Would a muon being 10x its stationary length make a noticeable difference in how long it took to go through the atmosphere? Obviously not, it's length would still be minuscule.
That's the flaw right there, you can't say that one frame contracts without acknowledging that it would be equally valid to say that the other frame lengthens or, to be even more logical, to look at as one frame contracting and the other lengthening by the same percentage. Of course, the real explanation for muons getting through the atmosphere before decaying can be found in the Encyclopedia Britannica. Go search their site for the topic of muons and see if relativity is mentioned anywhere in the page.
You just don't understand the math, the muon experiences length contraction however us observers see it as time dillation. We do not see the muon becoming longer and special relativity never makes such a prediction, instead to us it appears to experience time slower, hence it doesn't have time to decay.
I saw this video and Blow my mind , very interesting
Expertly analysed. Very well done. And thank you for mentioning Dialect's reference frame "choice" for the one way speed of light.
@0:36 The reason why physicists consider this theory to be correct is because experiments of time dilation directly correspond to two, one way speeds equalling 3×10⁸m/s.
The very fact it's impossible to measure the one way speed of light is further proof that Einstein’s block universe description of time and space is correct.
Experiments are consistent with two, one-way speeds equalling 3x10^8m/s. They are also consistent with an anisotropic speed of light. Neither is favored by experiment. And if you want to see that as evidence of the block universe then that is fine, but not proof. Scientists don't speak of proof (that's for math), they speak of evidence.
@erinm9445 Don't worry, SR math proves block time.
@@jack.d7873 There you go with that word "proof" again. It does no such thing. The block universe isn't even a scientific theory at this point, it's metaphysics, and while lots of physicists do believe in the block universe, lots don't. (The fact that you have to use the word "believe" is exactly how you know it's metaphysics).
@erinm9445 Where is the word believe?
@@jack.d7873 I used it. Talking about whether physicts believe in the block universe. Some do (probably the majority), but many don't.
One condition requires in the MMX to validate a null state is that light speed is isotopic and only isotopic.
This supersedes a principle we call - time dilation. Otherwise, if we choose to maintain both are valid, we have a bi-standard in our believes to defend with.
How can we fall for the stories of a man only do thought experiments indoor through his entire life.
I’m old, but if you are still young don’t follow his foot steps.
Move both clocks the same distance in each direction.
the time dilatation apply differently in both directions if the speed of light is anizotropic
@@lukasrafajpps I don't think it is anisotropic.
It is one frame of reference that is same for everyone: CMB
Relativity: "There is no aether."
Quantum Field: "Am I a joke to you?"
and the quantum field theory is relativistic so how could it be aether?
@@lukasrafajpps Ray Fleming discusses this at length on his channel..
@@jezzamobile He doesn't exactly look like a trustworthy source.
Is there an ether… it would be fine for QM… but QFT ?
One Planck length per Planck second. Always. But gravity is the mayor of the density of the metric.
move both the clocks in opposite directions at the same speed for the same amount of time
Can anyone answer this question? What if the one-way speed of light were vastly vastly different in opposite directions. Say it was 1 meter per second in one direction and 600,000,000 m/s in the other. Would it be in any way possible to detect that big of a discrepancy and if so why would it not be possible to detect a much smaller discrepancy?
there is a lower limit for the one way speed of light namely c/2
We can measure one way speed of ligth: th-cam.com/video/EtsXgODHMWk/w-d-xo.html
Yea the point that i never taught about is the direction EVERY DIRECTION
Classis use of the El Hospital rule, thanks!
I can't ever learn to spell it correctly :D
@@lukasrafajpps the spelling wasn't the problem but the pronunciation which is "lopital"
What if a frame R on x-axis sends two photons that are one second apart. An other observer within a frame R' on x-axis measures the first photon on a screen, then quicly open the screen and measures the second photon on another screen that is one lightseconds apart. The time between clicks appears to be one second. If R and R' are arbitrary, then the speed of light _must_ be a fixed constant in all reference frames 🤔
I don't know if I understand correctly. How can one observer measure a photon on two different locations?
@@lukasrafajpps 2 photons or 2 flash of light. The observer registers them both.
@@xjuhox but how? via light again?
@@lukasrafajpps The second observer receives two successive light flashes, and he is able to calculate the speed of light.
Apparently the relative speed must be taken into account in order the reciever to time dilate the one second of time. But I believe that this experiment justifies the fixed speed of light.
I've been following this series of Dialect for a while, and whether or not this k-factor does mean something or not is not the most interesting part. The most interesting part of his videos is how he talks about how Einstein struggled to reconciliate the fact that all motion is relative apart from acceleration, and that in the end Einstein was closer to accepting that there must be an ether. He brings the receipts, i.e. manuscripts of Einstein's to demonstrate that this was indeed what Einstein thought.
However, I'm neither a physicist nor a historian, so I cannot say if he's misrepresenting Einstein's arguments nor if what modern physicists think about absolute acceleration and it's place in relativity.
Science isn't an enterprize of priesthood. Even if Einstein denounced his theory completely, it wouldn't have changed anything unless experiment and observation shows something towards that. Theory of relativity can only be wrong if there's a absolute frame of reference. And there's no way that the existance of such a fundamental thing would be experimentally undetectable.
@@aniksamiurrahman6365 Totally agree that science isn't a priesthood! Dialect pointed out that many science communicators on youtube, both those with and without physics degrees, claim that they are using Einstein's interpretation of relativity, when his actual writings seem to tell that he was not sure how relativity should be interpreted. I just find that interesting, since interpretation of the facts is kinda important too.
@@jhuyt- That's right. People shouldn't claim using Einstein's interpretation. His own words, in his published books and papers are far more nuanced than can be included in a simple video. But Dialect is also a bit misinterpreting. Though his uncertainty about the interpretation of relativity is clearly seen in most of his later writting, falling back to aether only appears only once or twice. Looks like Einstein took it only as a distant possibility.
@@jhuyt- Sir, I also want to clear up something. The idea of space-time or quantum field very much coinsides with luminiferous aether except one very very important point: Aether has to be an "absolute frame of reference". All the mechanical interpretation Dialect is asking for necessitates this. Or else they fall apart. And without aether being a " absolute reference frame", it pretty much coincides with space-time/quantum field.
@@aniksamiurrahman6365 Thanks for that clarification! It's just interesting for me (as a layman with an engineering physics degree that has since moved to CS related work) to see this stuff from a different perspective that was hardly even discussed in my classes. I definitely do buy what he's saying wholesale, but I find the ideas interesting none the less.
Hello, just wanted to write out a few things that come to mind when watching these videos and reading their comment sections.
I think im pretty safe in assuming that most people watching these youtube physics channels have a great interest in the subject, would consider themselves quite intelligent in their respective fields, but dont necessarily have the mathmatical ability or physical expertise to be solving or even recognizing the holes in modern physics. If we did we wouldn't be frequenting physics channels unless we were looking for lecture ideas.
That doesn't make our opinions or efforts in learning the material lesser per se. But it does mean on average we might place more faith in the compacted, simplified youtube versions of physics explanations by our favorite presenters without the context and scrutiny that might be needed to have a full perspective of the topics being discussed. We have to place faith that what were being given on youtube is correct and if there is a deviation from the nuanced interpretation, whether by intent or accident, we dont necessarily have the tools to recognize it.
The point of Dialect seems to be to highlight this. They are putting up fairly bold claims and some relatively harsh criticsm for this small slice of the internet. I don't personally agree with every method they've taken but I do agree with the goal: inject scrutiny in this community and allow for mindsets that are less closed off to new interpretations - as should always be the goal in science no matter how absolute the current interpretation appears to be. Whether they've been too inflammatory in this pursuit can certainly be up for debate but lets not forget that they have a long term goal with their video series and they are very notably not done. Debating it now may in retrospect be pointless once we have a full persepctive on their finished content.
Either way the deed has been done now and it is up to us the community to determine whether good or bad will come from it. Dialect will play the antagonist for many and the physics channels will hopefully respond with great videos like this and provide greater nuance to the difficult subject matter being discussed. We will all learn more and appreciate more of the intelligent discourse surrounding these topics. And we will hopefully have clarification on misconceptions to this material that we didnt even know we had.
Be patient, and maybe even more so be kind. Were going to see a lot of belief speaking before fact in the coming days and how we handle it will determine a lot more about us as science appreciators than the soapbox comment section scientists that say they knew better the whole time. Dialects' shakeup could very well lead to a lot of bad science but even if it is it'll become good science if we harness the opportunity for learning and growth.
Now I'm wondering if Lukas and Dialect are making some kind of act on TH-cam to mutually increase their view count/view time.
:D well, I don't think I can significantly increase a view count of a dialect channel so it would not be wise from them to work with me :D
@@lukasrafajpps IDK man, with each new video, Dialect feels more and more like Physics equivalent of Intellegence Design advocate (I'm a Biologist, so I'm drawing equivalent from my field). Even with all his arguments, these things are either not experimentally detectable. Or, they don't seems to suggest much (actually any) experiment! That's surprising and alone is good enough to kick someone out as pseudoscience. But as you and many others shown, Dialect's arguments are seriously flawed. Both Physics arguments as well as Epistemological ones.
Your math is wrong. it's (1-1/γ)* S/v for how much time you lose at a speed (rather than how much time the universe gains at your speed relative to you, which you're really only interested in the clock in the moving frame, not the universe's clock)... 1/γ is sqrt( c^2-v^2 ) / c. a slow moving clock over the same distance does lose less time. You calculated it yourself that over 600lightseconds and at 0.000033c(10km/s in lightseconds/second) the clock would only lose a few ms (it's actually 9.9ms). This is much less than the 600 seconds that would be lost going the speed of light) (or 160 seconds at half the speed of light)... BUT - the speed of the solar system through the universe is 370km/s or 0.00123c(according to the red shift of the CMBR); and you would have to wait until a specific time that mars and earth are in a line towards Virgo... otherwise most other direction aren't going to have as much shift.
So- the mars clock is say 9ms delayed... the one way it would take light 600+73.8ms or -73.8ms worst case to get here... I don't see the issue.
0.000033c is 1/37 the speed overall, so if it happened to be going inline with Virgo to start the difference to the 9.9ms difference wouldn't be that much.
Second your anisotropic factor isn't right either 1) you didn't show what the compliment of k would be... 2) it would be a factor added to or subtracted from V like sqrt(c^2 - (v+/-k)^2)/c (which in the solar system's case is k=0.00123c (best/worst case). which over 600seconds is +/- 0.738 seconds; which makes the 9ms is an insignificant error.
(I did forget to contract the length.... 1/γ * S/V * (1-1/γ) = S/γV *( 1- 1/γ) = S/γV - S/γ^2 V = (γS -S)/ γ^2 V -or S/γV - S/γ^2V ; (personal comment 1/γ is so much more useful than γ ... but whatever) The additional difference from length contraction changes the distance only a tiny bit anyway... changing only decimals at 10^-12 seconds);
And no - not everyone can claim to be in a stationary frame. Consider 8 rockets passing the earth at the same time, that at that moment do have synchronized clocks, each travelling 0.1c more then the prior. Compute the relative time contraction for rocket 1 to 2 and for 7 to 8. They are all the same 0.1c apart, so they should all experience the same time dilation compared to the one before it... and yet at sqrt( c^2-0.7^2) - sqrt( c^2-0.8^2) is much larger than sqrt( c^2-0.1^2) - sqrt( c^2-0.2^2) (0.994 - 0.979 = 0.015) vs ( 0.714-0.600 = 0.114) .
so I don't know the specifics of these experiments that have attempted to measure a difference in speed by the relative speed of the receiver you mentioned at the end... but I'd expect since they are moving significantly slower than 0.00123c - that any small change is imperceivable. (Oh you said transmitter - no light doesn't inherit inertia that way - it would have to be a moving receiver relative to the emitter; and then the distance it's moving would have to be significant.
Interferometer experiments also need to factor in Light Aberration; and even with a constant 1 way speed of light one would expect a null result.
The last several videos on my channel are about this 1-way constant speed of light in a stationary medium of space (which moves only because of gravity really - as in LIGO detector). Links in descriptions go to docs on github and the demos....
The laws of physics would be the same - but it would mean that a force applied in the direction of motion vs opposite the direction of motion will impart a different velocity... this actually means that there is sort of a friction of space - that a force backwards slows down a fast moving object much more than a force forwards would accelerate it; but we can't go fast enough to make a significant change ... the parker space probe is only half of our speed through the universe at 159km/sec (vs 370km/sec)... and the force difference at 0.001c would be in the order of pico-newtons(maybe fempto - I didn't keep those calculations)... and if measured on a torsion balance would be accelerating masses in opposing directions and end up canceling it out... so the most precise measuring method can't be used... but even then - only if applied in a very specific direction.
the fact that the one way speed of light hasn't been measured might be an uncontroversial fact, but it's not very well known.
It's also completely irrelevant
I mean well known in what sense? It might not be well known among the general public but I don't think that's a good measure for anything when it comes to science, I mean extremely simply things like Newtons laws or Le Chateliers principle aren't known by the general public. Seems more relevant to discuss whether something is well known in the relevant fields.
But doesn't GPS assume a isotropic speed of light? And GPS works. What am I missing here...
Because they use Einstein's synchronization convention which is the same as picking the isotropic speed of light as default.
You can synchronize clocks by doing this:
Have both observers on the same orbit and orbital speeds but at opposite directions. When their distance from each other is nearly zero, they transfer their clock information to each other.
Yeah, that's the thing though... you can *only* synchronize (choose an arbitrary zero time) when both clocks are located at the exact same _time and place_ (basically where their worldlines intersect, because that intersection point of the two lines is invariant for all observers)
The time and distance in space both need to be zero, so the 4D spacetime interval is zero. Otherwise you will have a bunch of 4D triangles in spacetime with side lengths that can be arbitrarily chosen (as long as the sum of their squared lengths are constant). That's the whole clock synchronization problem.
(And yeah, you /could/ just tell everyone to use an arbitrarily chosen clock on Earth, or the center of our galaxy, or the cosmic microwave background, or in my butt... none of these are special, and none of these actually solve the problems. You (all observer reference frames) still can *not* say that Event-A occurs before or after Event-B, if the two events occur within the period of time that it takes for light to travel between two observers at different locations in space.)
Well, for the first 9 minutes you were using the speed of light to synchronize clocks used to measure the speed of light. Then you hurried though changes in the speed of light when radiating objects change their velocity. You spent just half a minute on that.
I agree I should say more about it but basically, for a distant double star systems we would see a violation of the Kepler's law of motion because due to difference in the speed of light the orbital trajectories would appear to be slightly different. This was not measured. Maybe try read about de Sitter double star experiment.
Maybe we should move from special relativity to general relativity? Lets consider a photon sphere around black hole. You can move in a straight line (geodesic) and do circles in left or right direction so you can have two photons moving in opposite directions and pass through each other periodically. If a photon is moving in a straight line there should be no reason for fluctuating speed of light along the path (except if our curved space is embedded in some higher special flat space that impose objective direction) so one photon would be doing faster circles around the black hole than the other in opposite direction if speed of light were different in each direction.
if you do a circular trajectory it means you have traveled in all directions and it would averaged out to a classical light speed.
@@lukasrafajpps By following a geodesic you are moving in a straight line so you are not changing any direction. You could also consider a flat universe with torus topology. By moving in one direction you would go back to the point of your start. Could such universe has different speed of light in different directions?
@@LordNezghul The orbit is actually kinda tricky thing for me in general relativity. yes you are moving in a straight line in spacetime but not necessarily through space as there are many ways how you can move through space and be on geodetic. I am not an expert on general relativity however so I won't be able to provide a more elaborate answer.
Here is why I see value in Dialect's interpretation, though I can't speak for him. (And while I think his videos are a little overly-dramatic, he doesn't claim he's presenting anything new, at least not so far, just shining a light on existing Dynamical Relativity theories that aren't well known).
Basically, special relativity asks me to accept some things about how time and space that make no logical sense at all to me. The speed of light being the same in all reference frames and not varying based on velocity is one, the relativity of simultaneity is another, and of course there is length contraction and time dilation. IAnd when you ask a physicist why any of these things are, they just say something like, "well, that's how the universe works." There isn't a deeper understanding, besides maybe a hand-wavey idea that minkowsky geometry is physically real--which still doesn't really answer anything for me. I just can't make a mental model for any of this in my head. And I have tried SO hard. Even the weirdness of quantum mechanics allows me to make mental models (however strange--or wrong--they may be). But special relativity just seems, physically, like nonsense. Nonsense with *incredibly* accurate predictions, but nonsense nonetheless.
Now, obviously, the universe isn't obliged to make sense to me. Maybe it really is nonsense to any kind of human logic, which is what I had accepted for a long time. But if there is an alternate interpretation of special relativity, one that retains all of the math and all of the precise predictions, but that makes intuitive sense to me, that doesn't feel like nonsense, that I can actually *understand* (vs just memorize, as is the case with traditional special relativity) then HECK YEAH I am taking that option. It doesn't matter if it's right or wrong so long as it makes the right predictions, what matters is that it a) helps me make mental models that give me much more accurate intuitions about how relativity works, and b) just makes me feel a lot better about the world I live in. It makes science feel weird, and not fake and made up. (No, I don't think special relativity is fake and made up, but since it has always felt like nonsense, I've never been able to shake an irrational feeling that it's all fake--which, again, isn't the universe's problem, but an alternative interpretation makes *me* feel so much better).
Dynamical relativity does this by restoring things that match our intuitions: absolute motion, absolute simultenaity, time that doesn't depend on observer/how fast you're going, a speed of light that obeys sensical physical laws (ie doesn't magically stay at the same speed relative to you no matter what), and an actual honest-to-god intuitive, sensical, easy-to-understand explanation for time dilation and length contraction (he hasn't gotten to length contraction yet, but I've looked into some other dynamical relativity resources to see the length contraction explanation). To me, that is an absolute revelation. It kind of seems to me like in the science world, it's seen as uncool or taboo to be uncomfortable with the weirdness of special relativity and to want the world to make logical, intuitive sense. But I'm not an actual physicist, and I am over the moon with finally having an explanation for the weirdness of special relativity that makes sense to me, and that I can wrap my head around.
It's important to add: Even if dynamical relativity is right, everything you say at the end of your video here is true: anyone can claim to be in a rest frame, and no one else can prove them wrong. Because everything we are made of matter governed by the speed of light, everything we do and everything we measure will always look like Minkowski spacetime. Special relativity in Einstein's formulation is still incredibly useful and by far the best mathematical formulation for understanding space and time as we measure and experience them. In this interpretation, length contraction and time dilation *are* real for us since we are made of particles governed by the speed of light, and that is why we have to use special relativity, not newtonian physics, to get the most accurate measurements. Anyway, just my personal thoughts on the matter!
By the way, thought you'd want to know how L'Hospital is pronounced. It's pronounced exactly like Loki Tall 😄 (as in, the Marvel character Loki), except with a "p" instead of a "k".
After viewing the dialect videos, the simultaneity, true lenght and true time to me, aren't concepts that we can observe in any "real" frame of reference, not a single one. Thus I have a huge surprise when you say dialect wants to choose a master frame to attain his purposes. From what I understood, the true length and true time and thus the simultaneity, can only be thought, be mentally calculated on paper but they can't even be directly seen. The same way that on the 3D space on earth no one can see true distances or true length, everyone has his point of view and the only thing in common that they all have is that they are all wrong, you can't chose any frame and say this is the "good" frame, because all of them are wrong in some way or another.
This might be my biased interpretation of dialect since my education is on geometry, not on physics. I'm looking forward about what he says next.
wouldn't infinity = 100% nothing or 100% something ?
Why not move two synchronized clocks from a starting point in opposite directions with the same speed? After some proper time T‘ they stop at the same distance away from the starting point. Voila: you know the distance and you have two synchronized clocks.
yes but only if the speed of light is isotropic otherwise each clock gets different time dilatation
@@lukasrafajppsis there theoretical or experimental reason to belive that the speed of light is not isotropic?
The question is not if GR is wrong or right. The question is if GR directly reflects a "fiber of reality" or if it is just a mathematical description of observable phenomena.
Since it is not a theory of everything the second option is almost certain but now, it is the closest to reality you can get.
Both Special and General Relativity are optical illusions. According to Special Relativity, 2 moving inertial observers will observe the space to contract and the time to dilate in each others frame. This is a contradiction and a physical impossibility. The only solution is that it is an optical illusion and it only appears that way. Any theory based on Special Relativity such as General Relativity will have the same problem. A simple Radio Wave antenna experiment shows that nearfield light is instantaneous and only farfield light is speed c. It can easily be shown that Instantaneous light yields Galilean Relativity, whereas farfield light yields Special Relativity. But since time and space are real and can not depend on the frequency of the light used to measure the effects of time and space, then the effects of Relativity must be an optical illusion. For more information see my short TH-cam presentation and the paper it is based on. William D. Walker and Dag Stranneby, A New Interpretation of Relativity, 2023. th-cam.com/video/sePdJ7vSQvQ/w-d-xo.html
But aren't we trying to prove time dilation? If we don't know that time dilation occurs until we have proven the theory of relativity but we are already supposing that if we move the clock then there will be time dilation.
Isn't this circular?
We're not trying to prove relativity. We're trying to show that it is consistent to just take the speed of light to be isotropic _for convenience_ .
That is not a postulate of relativity but a math choice.
We only need the two way speed to be constant to get a formula for time dilation. If the one way speed is different then the time dilation in different directions will be different and the effects cancel out to give the same result.
@@narfwhals7843
Suppose I never knew about relativity and I move one Clock from the other. How will I know that time dilation has a occured or not? If time dilation has not occurred then they will be in synchronisation but if it has occurred that we will not be able to know because we haven't proven time dilation yet.
@@NotesofKhan You can _observe_ the time dilation. The clocks will not be in perfect synchronization.
Or you do an experiment trying to detect the perfect rest frame (k=0), find that it is impossible(or arbitrary) and _deduce_ time dilation from that. Which is what Einstein and Lorentz did after the fail aether experiment.
We are taking time dilation as a given here because we are trying to show that the assumption of the one way speed of light in relativity has no consequences, we are not trying to derive relativity.
@@narfwhals7843
Thanks
So time dilation is an observation?
I know little
@@NotesofKhan Time dilation started as a prediction of Special Relativity in 1905.
It has been observed experimentally since then. See for example the Hafele-Keating experiment.
L'Hopital was a French mathematician. His name is pronounced loh-pee-TAHL not L-Hospital. Bad mistake.
Yea the point that i never taught about is the direction every direction