bangstrom Posted Wednesday at 10:04 AM Author Posted Wednesday at 10:04 AM 2 hours ago, Eise said: Funny enough, this 'dimensional constant' has the dimension of speed. Yes, it has the dimensions of a speed in units of distance over time but not all dimensions of distance over time are necessary a speed. It is more like the speed of a computer than the speed of a ballistic object. What Olaf Roemer discovered in the seventeenth century with his observations of the planets around Jupiter was simply a constant relation between measures of observational distance and observational time in the constant ratio of units c. Logically, however, although c has the dimensions of speed, it need not be interpreted as a speed. The idea that light ‘travels’ in any sense is pure supposition. We never see light leave an object and ‘travel’ through the vacuum of space from one object to another. Also, the observation that the speed-of-light has to be the same for all observers in all inertial reference frames is puzzling and defies common sense. It makes no sense that one speed should be the same for all observers independent of their individual, speeds. Observers in different inertial reference frames measure distance and time appropriate to their local conditions but they all measure time as a constant ratio proportional to distance and falsely call it a speed. 2 hours ago, Eise said: Today it is interpreted as the maximum speed of causality. EM waves in vacuum and gravity have exactly this speed. I have often heard of c described as the speed of causality and that sounds good to me. There must be a better term than “speed of causality." The rate of causality? The rate of correlation? Anyhow, it ain't a speed. 2 hours ago, Eise said: Nope, no action. It is correlation. The no-communication theorem shows that even in QM there are no none-local actions. 'Action' implies energy transfer, and there is none. I agree it's a correlation and I prefer to call it an “event” which doesn’t imply traveling through space. I prefer models where energy is lost from one location and simultaneously gained at another without traveling through the space between. This is what we observe as described in SR, with an interval of time that is always proportional to the distance between.
Markus Hanke Posted Wednesday at 11:27 AM Posted Wednesday at 11:27 AM 1 hour ago, bangstrom said: Also, the observation that the speed-of-light has to be the same for all observers in all inertial reference frames is puzzling and defies common sense. I don’t find this puzzling - just the opposite. The speed of light follows (eg) from Maxwell’s equations, so it would be a lot more puzzling if different observers experienced different laws of electrodynamics, especially since their speeds are not intrinsic physical properties of their own frames, but merely a measure of how they relate to other frames. Without this invariance of c, the universe couldn’t function, since you’d get unresolvable paradoxes.
exchemist Posted Wednesday at 12:13 PM Posted Wednesday at 12:13 PM (edited) 10 hours ago, bangstrom said: You were perfectly, clear that covalent bonds are an entanglement and I find the idea quite valid but it was just novel to me. It may prove to be important but as of now, I find it to be speculative but worthwhile to keep in mind among other possibilities. The idea of swapping states has been around for many years, even before what we normally think of as states were known. When I first learned of entanglement I thought such a bizarre phenomenon must be of some enormous importance but I had no idea what. Later I discovered the nonlocal, swapping of energy states among charged particles was a possible mechanism behind the transmission of light. The possibility was first proposed by Hugo Tetrode in “Zeitschrift fur Physik” vol.6 1922. Here is a quote from Tetrode’s article as translated by A. F. Kracklauer. Kracklauer advised the reader that Tetrode’s mention of atoms should best be understood as electrons. Electrons were unknown in Tetrode’s time. “Suppose two atoms in different states of excitation are located near each other, normally it is to be expected that they would have little influence on each other; however, under special conditions with respect to positions and velocities, possibly also in the vicinity of a third atom, it might be that strong interactions occur, Such a situation could well lead to an energy transfer between atoms such that their excited states are exchanged. The energy loss of one and the gain of the other could occur in a time interval corresponding to their separation; that is, we would have an instance of emission from one atom and absorption by the other. While according to classical understanding, emission is a random event leading to radiation that also randomly might somewhere at some time be adsorbed; here in this theory, the source and sink of a radiative interaction are virtually predetermined paired events. That is, in effect, the sun would not shine at all were there no other charged bodies in the universe to adsorb its radiation.”-Hugo Tetrode 1922 The model of swapping energy states among entangled particles is an important part of N.”Viv”Pope and Anthony Osborne’s “Angular Momentum Synthesis” POAMS and later in John Cramer’s “Transactional Interpretation Of Quantum Mechanics” TIQM. An excellent discussion of TIQM can be found in Chapter 5 of Carver Mead’s book “Collective Electrodynamics” and also in a 2020 collaborative article between Cramer and Mead. https://arxiv.org/pdf/2006.11365 Here is a quote from the article, “As illustrated schematically in Figure 1, the process described involves the initial existence in each atom of a very small admixture of the wave function for the opposite state, thereby forming two-component states in both atoms. This causes them to become weak dipole radiators oscillating at the same difference-frequency ω0. The interaction that follows, characterized by a retarded-advanced exchange of 4-vector potentials, leads to an exponential build-up of a transaction, resulting in the complete transfer of one photon worth of energy ̄hω0from one atom to the other. This process is described in more detail below”-Cramer and Mead 2020 Figure 1 and the quote can be found on p.4 of the article cited above. Cramer and Mead consider the energy states between entangled electrons to be oscillating rather than in superposition until the wavefunction collapses fixing the energy levels where they are found at the instant of collapse. But none of this is relevant to a pair of electrons in the same orbital, which is what we were talking about. For a start they have the same energy. And swapping states would in such a case imply swapping spin orientations, since that is the only difference between their states. As this, if it were to occur, would have no observable consequences, it seems to me to be an example of what Pauli described, in another context, as an "uncashable cheque", i.e. a notion that can be disregarded on the principle of Ockham's Razor. P.S. Tetrode is someone I've only previously come across from a thing I dimly recall from Stat. TD, called the Sackur-Tetrode equation. The only reason I remember the name at all is because I thought at the time what a curse it must have been to be named after a thermionic valve. 😁 Edited Wednesday at 12:22 PM by exchemist
swansont Posted Wednesday at 12:35 PM Posted Wednesday at 12:35 PM 5 hours ago, bangstrom said: Nonlocal action at a distance, aka entanglement That’s not entanglement, and if you are acknowledging the time delay corresponding to c, it’s not nonlocal
studiot Posted Wednesday at 06:03 PM Posted Wednesday at 06:03 PM I am finding this thread rather disappointing. For one thing I can't deteremine what it is about. Are we meant to be discussing Entanglement, the speed of light, action at a distance or what ? For another thing, if we are meant to be discussing entanglement it is rather distressing to be told that what happens before during and and after entanglement is irrelevant.
Genady Posted Wednesday at 09:44 PM Posted Wednesday at 09:44 PM 3 hours ago, studiot said: Are we meant to be discussing Entanglement, the speed of light, action at a distance or what ? They are entangled.
studiot Posted Wednesday at 09:52 PM Posted Wednesday at 09:52 PM Just now, Genady said: They are entangled. But what about them ?
Genady Posted Wednesday at 10:03 PM Posted Wednesday at 10:03 PM 10 minutes ago, studiot said: But what about them ? Misconceptions.
swansont Posted Wednesday at 10:20 PM Posted Wednesday at 10:20 PM 4 hours ago, studiot said: For one thing I can't deteremine what it is about. bangstrom has made some dubious claims about entanglement. This thread was split to speculations so they could provide evidence to support those claims, and the rest of us could rebut anything that’s incorrect.
exchemist Posted Wednesday at 10:21 PM Posted Wednesday at 10:21 PM (edited) 4 hours ago, studiot said: I am finding this thread rather disappointing. For one thing I can't deteremine what it is about. Are we meant to be discussing Entanglement, the speed of light, action at a distance or what ? For another thing, if we are meant to be discussing entanglement it is rather distressing to be told that what happens before during and and after entanglement is irrelevant. Surely what this sub-thread is about is a (dubious) assertion about communication, or action, taking place between entangled entities that are spatially separated. But a pair of electrons sharing a molecular orbital are not spatially separated, so there is no observational implication from them being entangled. Edited Wednesday at 10:21 PM by exchemist
Eise Posted yesterday at 08:10 AM Posted yesterday at 08:10 AM 21 hours ago, bangstrom said: It is more like the speed of a computer than the speed of a ballistic object. What a nonsense: the 'speed' of a computer is given in cycles per second, also known as Hz. Kinematic speed is distance (meters) per second, m/s. 21 hours ago, bangstrom said: What Olaf Roemer discovered in the seventeenth century with his observations of the planets around Jupiter was simply a constant relation between measures of observational distance and observational time in the constant ratio of units c. That is your interpretation of Ole Rømer's observations. It was defintely not Rømer's own: it was generally interpreted as the speed of light, e.g. Cassini: Quote This second inequality appears to be due to light taking some time to reach us from the satellite; light seems to take about ten to eleven minutes [to cross] a distance equal to the half-diameter of the terrestrial orbit. 21 hours ago, bangstrom said: Also, the observation that the speed-of-light has to be the same for all observers in all inertial reference frames is puzzling and defies common sense. So what? Then common sense is just wrong, as Markus succinctly explained above. 21 hours ago, bangstrom said: There must be a better term than “speed of causality." The rate of causality? The rate of correlation? Anyhow, it ain't a speed. Why then it shows up as a speed everywhere? it is the exact speed of EM waves in vacuum and gravity it is the limiting speed of information and of any object with a rest mass the wave equation that can be derived from Maxwell's equations (sqrt(1/u0e0) has the exact dimension of speed, and is indeed the speed of EM waves The last point I find interesting, insofar as the speed of light (EM waves) can be derived in such a way, because the speed of light is not explicitly the speed of light. I see it like this: u0 and e0 must have such values that they correspond to the structure of spacetime. And literally, a rate is a dimensionless value. But broader it must not be: speed is then the rate of distance to time. If it quacks as a duck... 21 hours ago, bangstrom said: I prefer models where energy is lost from one location and simultaneously gained at another without traveling through the space between. Fine, but in entanglement there is no energy exchange. Nature does not care about your preferences.
bangstrom Posted yesterday at 12:15 PM Author Posted yesterday at 12:15 PM On 12/4/2024 at 5:27 AM, Markus Hanke said: I don’t find this puzzling - just the opposite. The speed of light follows (eg) from Maxwell’s equations, so it would be a lot more puzzling if different observers experienced different laws of electrodynamics, especially since their speeds are not intrinsic physical properties of their own frames, but merely a measure of how they relate to other frames. Without this invariance of c, the universe couldn’t function, since you’d get unresolvable paradoxes. I don't find it puzzling that c is the same for all observers either. I only find it strange to think of c as the velocity of something traveling through space. Consider the absurdity of trying to measure the speed of light over the distance of a light year. Any attempt to measure the speed of light in time over distance is just a scaled-down version of the same impossibility since our units of distance, time, and c are all mutually defined. Given any two values, we can calculate the third. This is why c is the same for all observers and speeds are not intrinsic in their frames. The value of c is a universally observed ratio of distance over time and it has all the properties of a spacetime dimensional constant and none of the properties of a ‘speed’ as a velocity. If we consider c as a dimensional constant rather than as a velocity-speed, this simplifies our understanding of SR where c is simply a conversion factor for converting between units of distance and time. And the paradoxes of c as a speed disappear. The ‘pole and barn,’ for example. On 12/4/2024 at 6:13 AM, exchemist said: But none of this is relevant to a pair of electrons in the same orbital, which is what we were talking about. I agree that entanglement in covalent bonds is a different matter and what is happening in such close quarters is too speculative for me. 18 hours ago, studiot said: I am finding this thread rather disappointing. For one thing I can't deteremine what it is about. Are we meant to be discussing Entanglement, the speed of light, action at a distance or what ? As for me, I am interested in discussing entanglement which is action at a distance, and how c is a dimensional constant rather than a velocity.
exchemist Posted yesterday at 02:06 PM Posted yesterday at 02:06 PM 1 hour ago, bangstrom said: I don't find it puzzling that c is the same for all observers either. I only find it strange to think of c as the velocity of something traveling through space. Consider the absurdity of trying to measure the speed of light over the distance of a light year. Any attempt to measure the speed of light in time over distance is just a scaled-down version of the same impossibility since our units of distance, time, and c are all mutually defined. Given any two values, we can calculate the third. This is why c is the same for all observers and speeds are not intrinsic in their frames. The value of c is a universally observed ratio of distance over time and it has all the properties of a spacetime dimensional constant and none of the properties of a ‘speed’ as a velocity. If we consider c as a dimensional constant rather than as a velocity-speed, this simplifies our understanding of SR where c is simply a conversion factor for converting between units of distance and time. And the paradoxes of c as a speed disappear. The ‘pole and barn,’ for example. I agree that entanglement in covalent bonds is a different matter and what is happening in such close quarters is too speculative for me. As for me, I am interested in discussing entanglement which is action at a distance, and how c is a dimensional constant rather than a velocity. It has already been pointed out that no action is involved, and no energy exchange.
bangstrom Posted yesterday at 02:11 PM Author Posted yesterday at 02:11 PM 4 hours ago, Eise said: What a nonsense: the 'speed' of a computer is given in cycles per second, also known as Hz. Kinematic speed is distance (meters) per second, m/s. No, the speed of a computer and the speed of light are measured much the same. The speed of a computer is in cycles per second. Seconds are defined as the duration of time in a given number of cycles (aka transitions) emitted by a cesium atom and meters are defined as the distance light travels in 1/c seconds. Seconds, meters, and c are all mutually defined with c having a value defined by convention. It is redundant to try to measure c expecting to find it anything other than c because the value of c was a part of the calculations for deriving seconds and meters and a calculation can only yield the same value for c that was put into it. The speed of light can not be measured in m/s because that is essentially the same as trying to measure the speed of light over the distance of a light year. C is a ratio and not a speed. 5 hours ago, Eise said: The wave equation that can be derived from Maxwell's equations (sqrt(1/u0e0) has the exact dimension of speed, and is indeed the speed of EM wave This should be your clue that c is a dimensional constant and not a speed. It may have the dimensions of time over distance but not all dimensions of time over distance are necessarily speeds. This one is a ratio.
studiot Posted yesterday at 02:43 PM Posted yesterday at 02:43 PM (edited) Just now, bangstrom said: This should be your clue that c is a dimensional constant and not a speed. It may have the dimensions of time over distance but not all dimensions of time over distance are necessarily speeds. This one is a ratio. A characteristic of the last thread and now this one is that you keep introducing new material and words that require a whole thread or two on their own. What exactly is a 'dimensional constant' ? And since you claim that there are other physical properties or quantities that have physical dimensions LT-1 please list them because I can't think of any. ? (LT-1 ; Are you familiar with this notation ?) Edited yesterday at 02:44 PM by studiot
swansont Posted yesterday at 05:05 PM Posted yesterday at 05:05 PM 8 hours ago, bangstrom said: I don't find it puzzling that c is the same for all observers either. I only find it strange to think of c as the velocity of something traveling through space. It’s more than that. The speed of EM radiation traveling is just one phenomenon limited to c. 8 hours ago, bangstrom said: Consider the absurdity of trying to measure the speed of light over the distance of a light year. Any attempt to measure the speed of light in time over distance is just a scaled-down version of the same impossibility since our units of distance, time, and c are all mutually defined. Given any two values, we can calculate the third. Yes that’s absurd, but it’s not done, so what’s the problem? We do measurements of c over much shorter distances 8 hours ago, bangstrom said: If we consider c as a dimensional constant rather than as a velocity-speed, this simplifies our understanding of SR where c is simply a conversion factor for converting between units of distance and time. And the paradoxes of c as a speed disappear. The ‘pole and barn,’ for example. Again, it’s more than one thing. 8 hours ago, bangstrom said: As for me, I am interested in discussing entanglement which is action at a distance, But it’s not. If you’re going to claim that it is, you need to present evidence. Assertion isn’t enough. 6 hours ago, bangstrom said: No, the speed of a computer and the speed of light are measured much the same. The speed of a computer is in cycles per second. Seconds are defined as the duration of time in a given number of cycles (aka transitions) emitted by a cesium atom and meters are defined as the distance light travels in 1/c seconds. Seconds, meters, and c are all mutually defined with c having a value defined by convention. It is redundant to try to measure c expecting to find it anything other than c because the value of c was a part of the calculations for deriving seconds and meters and a calculation can only yield the same value for c that was put into it. The speed of light can not be measured in m/s because that is essentially the same as trying to measure the speed of light over the distance of a light year. C is a ratio and not a speed. In any system of units something must be defined, but the definitions involved were not always based on what we use today. The second was once defined in terms of the length of the year - “the fraction 1/31,556,925.9747 of the tropical year for 1900 January 0 at 12 hours ephemeris time” and the meter was the length of a platinum-iridium bar. Using those definitions it it entirely possible to independently measure the speed of light. But with our knowledge of relativity (and other physics) we’ve moved away from using physical artifacts and toward a more precise realization of the fundamental constants. On 12/4/2024 at 5:04 AM, bangstrom said: The idea that light ‘travels’ in any sense is pure supposition. We never see light leave an object and ‘travel’ through the vacuum of space from one object to another. We never see this, but having a minimal understanding of how light travels would explain why. The fact that you can block a beam of light with a shutter or index card (or planet or moon) at any point along the straight-line path from source to target is sufficient for most people to conclude that light travels through space.
bangstrom Posted 18 hours ago Author Posted 18 hours ago 13 hours ago, studiot said: What exactly is a 'dimensional constant' ? And since you claim that there are other physical properties or quantities that have physical dimensions LT-1 please list them because I can't think of any. ? (LT-1 ; Are you familiar with this notation ?) A dimensional constant is largely self-explanatory. I don't recall mentioning anything about the inverse of LT. I am guessing L is length and T is time. Could you explain? 10 hours ago, swansont said: Yes that’s absurd, but it’s not done, so what’s the problem? We do measurements of c over much shorter distances Measuring the speed of light over the distance of a lightyear is absurd. Suppose you find, after a year, that light travels more or less than a light year. Think about it. 11 hours ago, swansont said: But it’s not. If you’re going to claim that it is, you need to present evidence. Assertion isn’t enough. 13 hours ago, bangstrom said: If entanglement is not an action at a distance, then what is it? I am aware of different definitions but they all boil down to what Einstein called, “Spukhafte Fernwirkung” Spooky actions at a distance. 11 hours ago, swansont said: In any system of units something must be defined, but the definitions involved were not always based on what we use today. The second was once defined in terms of the length of the year - “the fraction 1/31,556,925.9747 of the tropical year for 1900 January 0 at 12 hours ephemeris time” and the meter was the length of a platinum-iridium bar. Using those definitions it it entirely possible to independently measure the speed of light. But with our knowledge of relativity (and other physics) we’ve moved away from using physical artifacts and toward a more precise realization of the fundamental constants. The value of c, as defined by convention, is now used is used to define both meters and seconds so we can not measure the speed of light in meters and seconds and expect it to be anything other than c. Imagine the absurdity of measuring the length of the platinum-iridium bar kept in Paris in meters or microns when that was our standard for a meter. Or the length of a tropical year in seconds defined as a fraction of a tropical year. Do you see the problem yet? 11 hours ago, swansont said: We never see this, but having a minimal understanding of how light travels would explain why. The fact that you can block a beam of light with a shutter or index card (or planet or moon) at any point along the straight-line path from source to target is sufficient for most people to conclude that light travels through space. The entire phenomenon could occur as a function of electron events. An electron could transfer a part of its energy to another electron, not through a trajectory in spacetime, but as two coordinated, simultaneous events. Light does not experience time so, for light, emission and absorption are simultaneous. We can never observe simultaneous events as simultaneous when they are separated by distance which always includes a relativistic interval of time at the rate of one second for every 300,000 km of space. The difference in this from the classical model comes with eliminating the concept of light as a discrete particle carrying energy through space. In other words, light does not exist between events, but only at the events
Eise Posted 14 hours ago Posted 14 hours ago @bangstrom Your are confusing 2 things: dimensions and units. The dimension of speed is distance over time, independent of which units you use: miles/hour, meters/second, feet/minute. For every different unit the value of c is different. If the units are fixed independently (with feet or arms of kings e.g.), the value of c is a measurement in terms of these units. But now physics has turned the definitions around, because of the rock solid empirical evidence that the speed of light is invariant. So now it is possible for every sufficient equipped laboratory to 'create their own meter or second' which will be exactly the same as in any other laboratory. Similar for u0 and e0. Because of the relation between these and the speed of light, and light now has an exactly defined speed, one can define the value of one in terms of the other. Further, let's go with your idea of a 'dimensional ratio': speed is a perfect example of such a ratio. It is the ratio of distance to time. So take my favourite definition of c: it is the conversion factor between space and time if one wants to unite space and time into spacetime, so if you want, a ratio (like an exchange rate of currencies). Now physics shows that this c is the limiting speed of causality: massive particles can never reach this speed, but can come as close to it as you want, given enough energy. Phenomena like light, gravity (and as I recently realised, the gluon field (gluons are massless too)), have exactly this speed. So we get that this ratio dictates the exact maximum speed of causality: a causal relationship involving massive objects can never be faster that c a causal relationship involving massless particles is exactly as fast as c a causal relationship involving 'just information' is dependent of the previous two. Information needs a medium, be it massive or massless particles. So 'information' is also bound to the limiting c. So this means that in entanglement, no information can travel fast enough to inform the other particle what e.g. its spin must be. So there is no information exchange, no causal relationship between the two particles, no action. And this is also not what follows from Bell's theorem. Two alternative formulations of what follows from Bell's theorem: If you measure the spin from 'your particle', you immediately know what the spin (measured in the same direction) is from its entangled partner. (Similar as the example of a left and right hand glove. Nothing travels from London to Sydney to 'make' the other glove a right hand glove.) But is only your knowledge of a remote event, and that has no limiting speed. Nothing in the measurement of the other particle shows that the first was measured. Only by comparing the measurements one notices the correlation. If you want to model entanglement with classical means, you would need faster than light communication. However, the quantum mechanical description does not need any communication. As said before, the reason is that the measurements of the spin of the two entangled particles are correlated: the interesting thing is that they are stronger correlated than can be classically explained. Given our daily classical conceptions, quantum entanglement is an astonishing phenomenon. But it follows directly from quantum mechanics itself, without needing information exchange. 4 hours ago, bangstrom said: The value of c, as defined by convention, is now used is used to define both meters and seconds so we can not measure the speed of light in meters and seconds and expect it to be anything other than c. Imagine the absurdity of measuring the length of the platinum-iridium bar kept in Paris in meters or microns when that was our standard for a meter. Or the length of a tropical year in seconds defined as a fraction of a tropical year. Do you see the problem yet? Do you see now that this problem does not exist? 20 hours ago, bangstrom said: As for me, I am interested in discussing entanglement which is action at a distance It is not an action, as explained above. 20 hours ago, bangstrom said: how c is a dimensional constant rather than a velocity. It is both, as explained above. 4 hours ago, bangstrom said: If entanglement is not an action at a distance, then what is it? It is correlation, as explained above. 2
swansont Posted 8 hours ago Posted 8 hours ago 9 hours ago, bangstrom said: Measuring the speed of light over the distance of a lightyear is absurd. Suppose you find, after a year, that light travels more or less than a light year. Think about it. Playing “what if?” is a useless game. What if we discovered magnetic monopoles all over the place? What if we saw things spontaneously starting to rotate? It would force us to rethink a lot of physics. But until there’s empirical evidence, it means nothing. 9 hours ago, bangstrom said: If entanglement is not an action at a distance, then what is it? I am aware of different definitions but they all boil down to what Einstein called, “Spukhafte Fernwirkung” Spooky actions at a distance. Einstein didn’t exactly embrace quantum mechanics. He was wrong, so why does it matter what he called it? 9 hours ago, bangstrom said: The value of c, as defined by convention, is now used is used to define both meters and seconds so we can not measure the speed of light in meters and seconds and expect it to be anything other than c. Imagine the absurdity of measuring the length of the platinum-iridium bar kept in Paris in meters or microns when that was our standard for a meter. Or the length of a tropical year in seconds defined as a fraction of a tropical year. Do you see the problem yet? If the value of c actually changed, then the length of the meter and duration of the second would also have to change to give us the same answer. i.e. things would have to actually get bigger or smaller. But we also have dimensionless constants (like the fine structure constant) that are actually constant, too. This isn’t the problem you seem to think it is. 9 hours ago, bangstrom said: The entire phenomenon could occur as a function of electron events. An electron could transfer a part of its energy to another electron, not through a trajectory in spacetime, but as two coordinated, simultaneous events. When you have a testable model of how this can happen, be sure to present it. Until you do, though, this is just bollocks. Science goes with the best theory it has for any particular phenomenon, and that means having a model and evidence to support it. 9 hours ago, bangstrom said: Light does not experience time so, for light, emission and absorption are simultaneous. We can never observe simultaneous events as simultaneous when they are separated by distance which always includes a relativistic interval of time at the rate of one second for every 300,000 km of space. The difference in this from the classical model comes with eliminating the concept of light as a discrete particle carrying energy through space. In other words, light does not exist between events, but only at the events Any notion of what light does or does not experience is fiction; we don’t have any physics that describes what happens from light’s point of view - it doesn’t have a reference frame. And again, when you have a testable model, present it. Anything else is just noise without a signal.
studiot Posted 7 hours ago Posted 7 hours ago (edited) 6 hours ago, bangstrom said: A dimensional constant is largely self-explanatory. This is what I mean by a derisory dismissive reply. What you understand by a dimensional constant is clearly not what I understand from the way you have already tried to use it. Here is my understanding of the meaning. I hope you will agree that miles (or any other distance) are not hours (or any other time). As every schoolboy used to be taught the distance walked is proportional to the time taken, at constant pace. He is then taught that this can be converted to an equation by introducing what is known as a constant of proportionality. Some proportional relationships are only used occasionally so the constant is just called the constant of proportionality. In the example case we use it so often that it is given a special name - the speed. In some cases the constant of proportionality is just a number because the two variables involved either have not dimensions at all or the same dimensions. But we have already agreed that variable distance is not the same as the variable time, So the constant of proportionality also performs a second duty. It 'converts' dimensions of time into dimensions of distance. In that case it can legitimately called a 'dimensional constant' and will be necessary even if the conversion is 1 hour walked converts to 1 mile covered. Note that I have used units rather than the more general dimensions, which brings us to our second point, which you clearly did not understand from you answer to my question which was to find out if we can usefully employ the standard dimensional notation. 6 hours ago, bangstrom said: I don't recall mentioning anything about the inverse of LT. I am guessing L is length and T is time. Could you explain? Nor did I mention " the inverse of LT". I mentioned L T-1 to the minus one which read the product of L and the inverse of T. And yes you did indeed mention the ratio of distance to time, or if you prefer the fraction distance over time. Anyway it is a remarkable and very useful fact that all the variables or quantities in Physics can be put in terms of a handful of basic ones. These are for Mechanics Mass M, Length L and Time T. We add to this Temperature (usually greek theta) , and a brightness or illumination measure for optics and a single electrical variable , formerly charge but now current density. So the dimensional constant has a suitable value to convert hours to miles or milliseconds to micrometre or whatever these are the units. It also has the dimensions to convert different types of physical variable. So speed has the dimensions of distance over time or L T-1 This makes the schoolboy equation distance = speed times time dimensionally correct since L = (L T-1) x (T) Edited 6 hours ago by studiot
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