AbstractDreamer

Well its from wiki and it looked more mathematical than the postulate that was purely in English at the top of the page, so i figured it would be more accurate. I have since read a few things on how Einstein initially was toying with the idea of variable c, but couldn't get the equations to fit. Then something about reconciling with gravity. My conclusion then is he put contraints and assumptions on GR and SR to make it work, which then turned out to fit empirical evidence. I'm more interested into what thought processes he had and what made him initially modelled c as variable.

Well that is your error of judgement then. What answer have i refused to accept? What is this agenda you think i have? You think I'm here to antagonise by questioning a cornerstone of accepted science? Then why even post a comment on my thread if you believe i have an agenda? Are you sure this agenda you're speaking of is not yours? Are you sure you're not on an agenda to antagonise me? What answers have i rejected? What answers have i not accepted?

You mean "no knowledge", and that is wrong, i do have some knowledge just not very much. What answers have i refused to accept ?- or are you assuming Im refusing to except them simply because i continue to ask questions? One answer cannot answer all the questions i have. I will refuse to accept answers such as "its not science", or "my ideas are random". I can go on wiki and and read the facts if i wanted to just accept current science with no understanding. The reason people come on a forum to ask questions is to get more than a 1 sentence answer and a link to something that the linker hopes will go way over their head and will shut the person up. Its complete cop out statement saying we need to learn it ourselves. Its basically saying you don't know how or cant be bothered to explain it in laymans terms. If you don't want to give an explanation fine, but don't make the comment of saying i just need to accept it or learn it myself. If nobody here wants to teach, Ill go somewhere else. Tell me, how do you think someone who is asking questions and trying to learn going to possibly PROPOSE AN ALTERNATIVE? You want the student to come up with an alternative, while you expect them to accept your answers on faith? I can accept this answer, because I have already suspected as such from even before my original post. But my curiosity wants to know some examples of these places and combinations, or some numerical examples to show why a tweak would be impossible, to get my thought processes going. How can i possibly learn it myself if i don't know where to look? I want to get some kind of idea how impossible it is. The evidence is that we know that GR and SR are incomplete. Isn't that enough? I really would have thought anyone who could answer my questions, would not need to be shown the postulates to know them and what the typical questions such as those that im asking might be, and not actually need them to provide the same answer they have no doubt given many times before, or even asked themselves when they were students. https://en.wikipedia.org/wiki/Postulates_of_special_relativity

Do the postulates of SR hold for when \( t<=10^{-43}seconds )\? If the answer is No, then not all frames of reference over time are valid, and that special relativity at best is incomplete. Do the postulates of SR hold for when \( (x_{1},x_{2},x_{3} \) are spatial coordinates that fall precisely on the event horizon of a black hole, where there is still empty vacuum between that position and \( (y_{1},y_{2},y_{3} \) If the answer is No, then not all frames of reference over space are valid, and that special relativity at best is incomplete. The idea of inflation in the extended \( \lambaCDM \) standard model of Big Bang cosmology employs fine tuned parameters to preserve the apparent homogeneity and isotropism the flatness of the CMB, and scarcity of magnetic monopoles that we observe in the universe today. Amongst the criticisms are untestable predictions, lack of experimental data, and arbitrary parametising of initial conditions that only increase as you go back in time if entropy from thermalisation increases as time progresses (Occam's Razor should seek simplification, not more initial conditions). A variable c theory can also preserve homogeneity, isotropism, and flatness of the CMB, if, instead of inflation, that c was faster from say 32 to 60 orders of magnitude But while these criticisms have been accepted by the community to support the standard model, the same arguments are used to refute ideas of a variable c. The hypocrisy is surprising. Eternal inflation is one of the many models of inflation theory, and some variants include the prediction of different volumes, or multiverses, that are interactably exclusive each other, and each running with different values for the physical constants. Is this the kind of forum where everyone has to get familiar with a subject before asking a question or face being scorned? Does my complaint carry less weight because I'm a novice? While the people answering me have spent more time on the subject, they seem more intent to focus their attention on telling me how wrong I am on some irrelevant point, or how its not science, or how i need to come up with a theory, or that I cant accept some answers, or missing my point, not reading my posts, asking me define something I already defined, jumping to an absurd conclusion about me wanting to test every electron in the universe, accusing me of random ideas, resorting to ridicule using analogies of flying unicorns; instead of actually answering any of my questions. Having read a little on fine-structured constant and spectral emission lines of hydrogen, I now understand it something to do with the how the energy levels of an elementary particle such as an electron may be excited and jump to a level above ground state due to spin orbit interactions between the electrons magnetic dipole and the magnetic field created by its orbit around a positively charged nucleus; and in doing so release mission spectra lines that are very close but separate. \( \alpha = \frac{e^(2)/\hbar c}{4 \pi \epsilon_{0}}= \frac{\mu_{0} c e^{2}}{2 h} \) It would be far more sensible to change the value of the reduced Planck's constant seeing as it is related to the porportionality between a quantum particle's energy and frequency, or momentum and wavelength. On a new-magical note, if \( \hbar \) is also a function of time or space, or time is a function space, wouldn't c necessarily be variable? Doesn't everything matter if you're trying to accurately model quantum physics? Or is it safe to assume nothing happens whatsoever while in transit over billions of years light years for billions of years, through numerous quantum fields that mutually interact , other than redshift from expansion and lensing from gravity? What kind of consequences? What kind of implications? How would the universe look if c was constant, but a different value? How would the universe behave if c was not constant? Is it not possible for there to be a reasonably simple solution to balancing all the equations to consider a variable c that varies only in special situations, yet only alter the consequence in those special circumstances? I'm asking questions on the invariance of c. That's not the same as suggesting or claiming that c is variable. In order to question the invariance of c, and seeing as there is no persons in support of that position, someone has to be devils advocate. You can jump to any conclusion that you want to believe, but you're mistaken. I took the mathematical expression for the 2nd postulate from wiki. Sure, by all means help me understand.

There is a difference between measuring an observable that is really old, and measuring an observable (instantaneously) from a long way away. There's no reason to believe that the spectrum must have changed, perhaps the observable has a different relationship? Why could the spectrum have not changed as it passed through space? Why does any change have to be magical? Again I have not done enough reading into alpha or fine structure, so you are forcing me into simply taking your word for granted, which ironically is how religion works, not science. You need a theory before you can experimentally test it. You need an idea before you can build a theory. That is how science works.

Well that is another of many alternatives. But my main position is that No, any photon measured locally in space and time must be c. But measured across significant time or space, FROM any position, there is no experimental evidence that it must be invariant. Other than this alpha or fine structure constant explanation that i need to explore, or the Occam's razor argument where various constants are all changing in some extravagant dance of deception such that c is invariant is more complicated than the simpler answer that c is always invariant across time and space.

Supersymmetric string theories consists of ideas that cannot be observed. So accordingly is it not science then? All those physicists and mathematicians... are you calling them non scientists because they are researching stuff that cannot be observed? That is a poor definition of science, if that is your lesson. Occam's Razor, I'm in favor of the simplified solution, if it is indistinguishable. I have been given the an answer in "alpha" whatever that is and the fine structure constant. I will have to do research into their connection with a constant c. It's not that i refuse to accept your answers, its that none of your answers have justifiably shown me why i should accept them, other than your word. It's not that I don't believe you, its that you haven't explained why. Neither do I believe you have given much thought into my position about its plausibility, and I have little confidence that you have brought about any significant weight of your expertise in the field into this thread other than fobbing it off as my problem, because even as you are convinced c is invariant, you have not actually shown me why. That is close to the point i am making! The velocity may have been different eons ago in time, or eons away in distance, BUT we cannot measure it to be anything other than the velocity that c is today around here. We are experimentally limited to measurements of observables that are locked in local space and local time, such that any measurement must inevitably result in an invariant c.

Ok I don't know what alpha is. The interactions you are observing are billions of years old, but that's because the OBSERVABLES are billions of years old. You are NOT measuring the interactions as they were then from billions of light years away. You are measuring them after their observable has traveled through billions of light years for billions of years. If you do not acknowledge the difference, theoretical physics is the poorer. I'm not demanding impossible tests. I'm curious as to why the community is so against the idea of a variable c, when the possibility of one doesn't necessarily have to have such an drastic affect on currently accepted models, and yet the only arguments I'm hearing is impossible to test, flying unicorns, circulus in probando, and argumentum ad hominem

No, flying unicorns is crazy. Variable c is within the domain of questionable physics.

I already have defined those special circumstances. When time is a long time ago, or a long time in future. Or when distance is a long way away. I'm not here to do science, i'm here to ask questions about science. Its not a random idea. It taken from the 2nd postulate of special relativity where there is no limitation stated on (s-t), nor is there any limitation on inertial frames of reference. I am simply questioning those limitations. You have already hinted that during inflation, there are some theories to a varying speed of light. So when t=very early on, physics were different and special relativity fails, but the postulates do not reference these limitations either.

The photon is a billion years old, but the MEASUREMENT is 400 years old of a photon that has aged a billion years. It is NOT the measurement of the photon a billion years AGO. By frequency do you mean intensity? What is the equation that is dictated by c? What are the other constants are involved?

But I'm not asking to test every electron in the universe. I'm not asking to test every inertial frame of reference. I'm asking to test ONE inertial frame of reference 10 billion light years away. It is NOT looking at alpha as it was then billions of years ago. It is looking at alpha today that has already aged billions of years. If the speed of light were invariant under circumstances beyond that tests for special relativity, then none of the tests would fail to match predictions.

You are entirely missing my point. You're attacking me with all the usual "science is not about proof" spiel, even though it might be a mistake I have made in my comments, is not the message I'm trying to convey. I have valid questions on the invariance and constance of c, and instead of trying to answer them or tell me why they are not valid, you are trying to school me on what science is about. Telling me to read your first answer when you yourself haven't understood mine is frustrating. But I will say it again. Length contraction and time dilation are both predicted by special relativity, and proved to real phenomena through experimental tests. Both also rely on c being "constant" and "invariant". This does NOT necessarily mean that if c was NOT invariant or NOT constant under special circumstances, that time dilation and length contraction would no longer be real phenomena under other circumstances.

Well correct me if I'm wrong. Because if gravity is quantum, then there must be some distance where it falls below the threshold for a measurable observation, even if it is beyond the distance of the cosmic event horizon for that observer. And at that distance where no measurable observation of the gravity field of an object can be made, it can no longer gravitationally interact with anything. If such a limitation to gravitational range exists, how can it also work over infinite distance unless you are talking about distances in dimensions above the 3 spatial dimensions.

Length contraction and time dilation are both predicted by special relativity, and proved to real phenomena through experimental tests. Both also rely on c being "constant" and "invariant" - over the limitations of the tests. None of this am I questioning. I have no evidence whatsoever to presume c changes over time. I'm asking what evidence is there prove it doesn't, to make it the 2nd postulate of special relativity. I don't have knowledge of these tests, and do not understand these limitations. It is my guess that these test were not - can not - be done on EM radiation that is older than 400 years, because humans did not start testing until 400 years ago. I'm not talking about measuring the velocity of an EM radiation being measured today, here at velocity c originating from the source a 10 billion years ago, I'm talking about measuring the velocity of EM radiation a few billion years ago - as it was THEN 10 billion years ago. It is also my guess is that these tests were not - can not- be done on EM radiation further than 0.0019 light years from earth, as that is the distance that Voyager 1 (the furthest spacecraft to date) has managed to reach. I'm not talking about measuring the velocity of an EM radiation being measured today, here at velocity c originating from a source 10 billion light years away I'm talking about measuring the velocity of EM radiation 10 billion light years away - as it is NOW, over THERE, from HERE, 10 billion light years away. Showing up in a lot of places, and there being a lot of evidence that c is constant and invariant I don't disagree. But logically, that simply does not prove that in ANY inertial frame of reference and ALL time coordinates that it is invariant and constant. We observe spectra from distant galaxies yes. But we can only observe them today at time t=now. Which of course is the same c as it was since experiments began 400 years ago. Looking at alpha today is not looking at alpha a long time ago nor is it looking at alpha a long way away. Is there any proof that if c was not constant or not invariable, that special relativity is necessarily wrong and not simply incomplete? What would happen if c is invariant and constant, but simply a different value? Are there any theories or equations that would cease to work? Would that change anything about the laws of physics? Why would it drastically change the laws of nature, if these changes were simply beyond anything that might affect you? Unless you were to travel a cosmologically long distance or time away, you wouldn't know any different.

Well yes when the reference is hard to find. But this is wiki. https://en.wikipedia.org/wiki/Quantum_gravity If gravitational effects only appear at length scales near the Planck scale, it didn't sound wrong to say quantum gravity operates over distances of Planck length. If gravity works over infinite distance as you say, and its strength is proportional to inverse square law, then it cannot be quantum. if gravity is quantum, then there must be some distance where it falls below the threshold for a measurable observation, even if it is beyond the distance of the cosmic event horizon for that observer.

"One of the difficulties of formulating a quantum gravity theory is that quantum gravitational effects only appear at length scales near the Planck scale, around 10−35meter" maybe my interpretation was wrong.

Invariant means it doesn't vary. Constant means it stays the same. Essentially, in language, the two words are synonyms and have the same meaning. I'm not mixing up two separate ideas here, I'm asking two separate questions, though I might be using the wrong words. But now I understand in physics semantics invariance is specifically related to a transformation reference and constant is related to a time reference. However I had hoped my explanation was clear what I was asking, but maybe not. a) If c is invariant in all frames of spatial reference - including extra-galactic distances. How has this been tested? If every test of SR has been done over relatively short distances, doesn't that leave an obvious question to be answered? b) If c is constant in all frames of time reference - including a long time ago and a long time in the future. If it has changed, what effects might we see?

If gravity is quantum, then infinitesimal might not be enough excitation to create a single quantum of gravity that is interactable or observable. If gravity is not quantum, then infinitesimal is still a gravitational field. According to wiki, quantum gravity operates over distances of plank length, which is pretty infinitesimal.

Special Relativity is formulated from an assumption: 2. Second Postulate (Invariance of c) There exists an absolute constant \(0<c<\infty\) with the following property. If A, B are two events which have coordinates \((x_{1},x_{2},x_{3},t)\) and \((y_{1},y_{2},y_{3},s)\) in one inertial frame \(F\), and have coordinates \((x'_{1},x'_{2},x'_{3},t')\) and \((y'_{1},y'_{2},y'_{3},s')\) in another inertial frame \(F'\), then \( \sqrt { (x_{1}-y_{1})^{2}+(x_{2}-y_{2})^{2}+(x_{3}-y_{3})^{2} )}=c(s-t) \) if and only if \( \sqrt {(x'_{1}-y'_{1})^{2}+(x'_{2}-y'_{2})^{2}+(x'_{3}-y'_{3})^{2})}=c(s'-t') \). It appears this postulate makes no limitations on \((s-t)\) even if it is on a cosmological coordinate time scale. Assuming local c was first measured around 400 years ago and hasn't changed since, why should we assume that it was also the same 13 billion years ago, and will be the same 13 billion years in the future? Can we prove that c has always been invariant and will always be invariant? Can we prove that this is true for any and all inertial frames of reference. Given an inertial frame of reference at location in space at the edge of our observable universe, how do we prove that the speed of light here in the Milky Way, as measured using units of time and distance from over there, will be the same c as they are experiencing over there?

How do you have momentum without mass? Do all massless particles have the same energy? Will a gamma ray photon have greater gravitational effect than visible light photon? If gravity propagates at the speed of light, from a photon travelling at the speed of light, how does this effect the gravitational field created by the massless excitation in the electromagnetic field?

How do you remove the presence of an electromagnetic or gravitational field from a macroscopic or microscopic test environment, or rather how can you prove that the value of the charge or gravity is locally zero? Let's take electromagnetism. Any test on Earth or close by will be subject at the very least to the Earth's magnetic field. If you create a shielded volume, how do you measure and prove there is no charge inside? Must any device that measures electromagnetic field interact with the field itself and potentially change it? Let's take gravity. Any test involving mass-ive equipment will be subject to gravity. Can you actually observe an absolute certain measurement for gravity, or only calculate it - is it subject to the uncertainty principle? Is gravity quantum? If the strength of a gravitational field is proportional to inverse square of distance between your measuring device and the object, then is the value of the gravitational field really zero in some deepest parts of space where there is no mass anywhere within a distance that creates an excitation in the gravity field of 1q other than the device you are measuring with?

Well my point was about comparing the scale of solar panels required as the problem, compared with the technology of fusion required. Pulling some random figures out of air.... building solar panels spanning 1 million km square, or a £4 trillion orbiting fusion reactor (that hasn't been invented yet... unless the vacuum problem can be solved with building the thing in space!) So far as getting the energy back to earth is concerned, how about geosynchronous orbiting laser firing energy back to earth? It would be easier to attach a fusion reactor to this than some vast array of solar panels.

Well on that point, which is more practical: a fusion reactor satellite in orbit around the earth, or solar panels in space? Assuming the problem with energy transfer is the same for both systems. Perhaps, the planet sized fusion reactor solution is better suited to interstellar travel. Good point on centrifuge. Ok lets turn it around... On the point of fusion,... a Shell of deuterium, inside of which protons are centrifuged into fusing with the shell. I'm guessing deuterium is liquid near absolute zero, but will be gaseous near the reaction plasma. So a liquid body of deuterium with protons in the core, spun to create centrifugal induced fusion. On the point of confinement, I'd have to speculate on quantum anti-centrifugal forces https://arxiv.org/pdf/quant-ph/0108069.pdf Apparently, possible either with negative energies with a delta-function potential, or with positive energy with vanishing angular momentum, in a two dimensional eigenstate space.

Just read an article on nuclear fusion http://www.bbc.co.uk/news/blogs-china-blog-43792655 while eating my oatmeal porridge I drifted off with wild fantasies of imaginations, which needed some more knowledgeable people to ratify or ridicule. If leakage is a problem, why not just build it in space? Nature worked this out a long time ago! What about using the center of a gravitational well to mitigate the electromagnetic cost to confine the reaction. Is there a planet or moon with center that is plausibly cool and low enough pressure in which to build a reactor, but of sufficient mass to be significant in confining the plasma? Can also use the body mass itself as the actual walls of the reactor, to both absorb and to transfer the output energy? The body might be slowly destroyed and consumed eventually over time, but that's a problem for the next eon. A planet-eating fusion reactor is cool! What about centrifugal forces as an supplement to electromagnetism in fusion confinement? Is it more efficient or precise to control an object's rotational motion to control a fusion reaction, than do achieve the same result with electromagnetic fields? So the plasma is "spun", not just "squashed". Are lasers only required to produce high symmetry with the fusing particles, to make it the reaction more precise and easier to contain? It is possible to generate enough centrifugal force to fuse a deuterium nucleus and a proton? Say a large mass of deuterium with protons in centrifuge around it, increasing the energy in the protons until some start to fuse? How do you impart angular momentum to an object in a vacuum, with nothing to "push back against"? Stored chemical energy in rocket fuel can be released with exhaust, but what if the object is atomic sized? Is the artificial gravity from centrifuge only a relative force, and not something "real" that might affect fusion? Maybe the answer lies not in precision, but in scale. A moon-sized fusion reactor, in the vacuum of space, near absolute zero temperature environment orbiting in the permanent shadow of a planet. The reaction occurs at the very center. The body's mass is used both as a natural shield and as the structure used to house the lasers, electromagnets, and energy collection. Brain dump over, I'm late for work.