Why The Theory of Relativity Doesn't Add Up (In Einstein's Own Words)

[@ScienceClicEN]

Yet again a fascinating video! I am wondering however what prevents us from defining "acceleration" as the anisotropy of the laws of motion? For instance: in an accelerating frame, a spring changes length if we rotate it, and objects which are initially at rest start moving in a specific direction, which indicates that there is an anisotrpy in the laws of physics for this observer. In this sense, an "inertial frame" can be defined as a frame in which the laws of motion are isotropic. Or more generally, an inertial frame would be a frame in which the laws of physics have a maximum amount of symmetry. I am probably missing something but I don't see why this would fail? In a way this is related to the fact that - even though time and space are relative - spacetime itself is absolute (in the "orthodox" interpretation of relativity) : we can tell whether or not a line through spacetime is straight or curved, using this anisotropy approach. And acceleration is the fact of turning / changing direction through spacetime.

[@mjmulenga3]

Not a physicist, but I see no problem with this definition of acceleration.

[@longextinct]

Exactly what I was thinking. Fundamentally, an acceleration upon an object is not some magical calculation we do by taking observations on its velocity at different points in time with respect to a single inertial rest frame; that process is but a mathematical formalism. In reality, an acceleration is the culmination of tiny particle collisions. From this purely objective viewpoint, acceleration becomes clearly absolute, a phenomenon which can be described as a sequence of causal events, and the product of such a culmination is that the object “shifts” into different frames of reference. This “shift” takes place in quantized steps of the collisions which constitute it. A way I’ve learned to think of such a process is through the fact that any and all transformations from one inertial reference frame to another exist in reality on a continuum, and an object in acceleration may transition between these absolutely existing dimensional objects, until the acceleration ceases, and the object once again returns to an inertial frame, but now a different one. Conclusively, if we define acceleration as a being fundamentally just a product of change, we can describe it as absolute, as it is clearly causally different from objects in inertial rest frames.

[@rudyj8948]

Crazy to see one of my favorite physics-tubers commenting on another of my My fav physics-tubers video lmao you guys rock

[@pyropulseIXXI]

Well, you can say the same thing about velocity. If everything accelerates at the same rate, then you cannot detect that; that has to be an acceleration relative to something else, but this would just go infinitely down due to infinite derivatives potentially, so we just define inertial frames in as simple way as we can But just like velocity, you can always change to a frame that gets rid of the acceleration; it might be more difficult, but it is possible. Yes, even in a rotating frame, because the rotation is always relative to something else; this gets into the deepest notions of whether absolute motion exists or not. If two objects under a spring where the only thing that existed, would absolute rotation bee detectable? That is, does absolute rotation exist? Or is it relative? That is, if you don't have a background to measure against, it can be said to not be rotating and instead just moving away from each other and stretching the spring; it is utterly indistinguishable from non-rotation linear motion in this case Furthermore, some say a thing won't even do this without a background reference. Put another way, if the entire star field started rotating, would this cause you to feel a rotational force? And if I started rotating myself at the same rate as the star field, would I no longer feel rotational forces since there is no longer relative rotational motion?

[@booJay]

@@rudyj8948 was about to make the same comment

[@buckeyefan9251]

I'm not a mathematician, physicist, or engineer. I'm just a finance and accounting guy. BUT I LOVE THIS CHANNEL. THANK YOU !!!

[@StarNumbers]

Got a nice heart just for shouting...

[@jenda386]

Great, thought-provoking video. I would just like to point out that constant speed of light is not merely an axiom. It is one for special relativity; however, the fact that the speed of electromagnetic waves (light being one type thereof) is constant and independent of observers comes as a clear result of Maxwell's equations and their solution for space without point charges and macroscopic currents. This result was measured and verified countless times since then. This is in stark contrast to Galilean relativity whereby velocities add and this problem puzzled physicists for more than 40 years. The reason Einstein's 1905 paper is called "On the Electrodynamics of Moving Bodies" is, that he attempted to resolve this apparent contradiction between classical mechanics and electromagnetism.

[@botplays6893]

You are correct, however I don't think this is necessary to point out, since almost every axiom ever devised is built on those who came before.

[@dialectphilosophy]

Actually, it IS an axiom. This may seem surprising and a little counter-intuitive, given that we have verifiably measured the speed of light to be constant. But the first thing to note is that we only ever measure the two-way speed of light (there are some great videos on KZbin about this subject already) so indeed the axiom ought to be refined to specify that the one-way speed of light is still unknown. In the Lorentzian view, light travels at different speeds but the shrinking of measuring instruments and the dilation of clocks obscures this result, such that the two-way speed always remains the same. So in other words, we can assume axioms other than Einstein's constant-speed-of-light to be true, and yet still recreate all the empirical observations we observe. (Whether such axioms are "better" or not usually of course depends on their logical consistency within a greater framework and/or their explanatory power.)

[@444haluk]

6:50 No it is not. Any uncalibrated measurement unit still gives you the true absolute "measurement", not output. If it is 2 times smaller than m/s², then every possible movement is (according to that information you receive). But it still measures without a reference.

[@ziplockbaggies8707]

WRONG 😑

[@antonk.653]

I agree, calibration isn't needed to detect a change in acceleration for a particular direction. If you are worried about a pre-tensioned spring, just flip it 90° sideways and it relaxes. Boom, you just measured the direction of acceleration, or in other words: A break in the conservation of momentum, therefore you are not in an inertial frame.

[@mhirasuna]

At 6:30, the accelerometer is calibrated so it can measure acceleration apart from gravity. But in general relativity, acceleration is equivalent to gravity. You can assume that you are not moving and measure gravity by just dropping something; no calibration needed.

[@mhirasuna]

At 7:25, there is a graphic that says, "Free Body Test, requires calibration is a system where bodies are assumed to be free". Well any object that you drop is a free falling body, hence it is in its own inertial frame. You might say that it is self calibrating.

[@arctic_haze]

Exactly. GR has already solved this problem, over a hundred years ago.

[@leonsprenger7952]

Exactly. In other words: you calibrate the spring without a mass attached and then attach the mass to observe any difference. In other words, I think the arguments from 6:30 - 7:30 do not hold.

[@J7Handle]

Guys, accelerometers don't exist in the realm of particle physics anyways, but as particles still experience time (radioactive decay, for example), they still need to participate in relativity thought experiments. Accelerometers are no longer valid in the solution to the twin paradox when you alter the twins to be mere electrons (or muons, so that they can decay after a certain amount of time). So the video may not have argued this very effectively, but accelerometers are still not adequate to measure absolute acceleration.

[@pepegrillo9722]

@@mhirasuna But "free falling" is not really "free"-falling; If the experiment is conducted on space with an "earth calibrated spring", where there is air resistance, air pressure, earth's gravity, then how is that self calibration useful to measure acceleration of an object inside a rocket that launched from earth and left the solar system, where earth's air pressure, resistance and gravity don't factor in? How about the earth's acceleration, solar system acceleration, the galaxy acceleration, the universe expanding acceleration affecting the "free falling" spring? None of that can be extracted from the spring at the moment of calibrating, yet of course those will affect the measurements one way or the other.

[@ThoughtsAreReal]

You keep interchanging velocity and acceleration. A person standing on the surface of Earth is "accelerating" at the speed of the gravitational force, like 32 meters per second per second. But their velocity, relative to the patch of ground on which they stand, is zero.

[@dialectphilosophy]

Hey everyone, thanks for coming by the channel! When watching this video, please keep in mind that all the arguments presented here are Einstein's, not ours (with the exception of the Kretschmann objection, to which Einstein only ever half-ceded). So if you wish to raise an objection or criticism, try and do so as if you were addressing Einstein himself, a man whom in all likelihood (and we speak merely from a probabilistic standpoint) was a great deal smarter than you. For instance, if you wish to assert that acceleration is absolute, you must fully address Einstein's critique as presented in his 1914 paper: how is it that acceleration is absolute if all we can ever observe is the relative acceleration of bodies? Here again, saying, "use an accelerometer" is not a proper response to Einstein's objection, because an accelerometer is still merely only the observations of bodies in motion relative to you. (Indeed, it is rather akin to saying "just use a clock" to prove that time is absolute!) Lastly, please be respectful in your comments and when responding to others. Disrespectful commenters, trollers, spammers, and other ill-willed remarks will be removed from the channel. Thank you!

[@hansolo9892]

Great and appreciate the work! keep going!!!!

[@dannylad1600]

Hey Dialect, don't you not think that stress v strain relationships of certain materials, like steel for instance, can be used to measure acceleration independently, regardless of who the observer is? Wouldn't this suggest acceleration is absolute? For instance, if you measure how much a simply supported steel beam deflects under it's own weight, it would measure an acceleration of 9.8m/s/s. Now if it went into freefall the deflection of the beam becomes 0 mm, therefore the acceleration can be measured as 0m/s/s.

[@user-lb8qx8yl8k]

Dialect I would imagine some of the content is related to his 1905 paper on special relativity!?

[@hansolo9892]

@@user-lb8qx8yl8k The controversy is mainly due to the 1914 paper.

[@siobhangraham7280]

Einstein was writing in 1914, before the overwhelming majority of experimental results confirmed Relativity. Additionally just appealing to "Einstein was smart, therefore right" is not reasonable. Einstein also refused to accept quantum mechanics, and yet quantum mechanics is a correct formulation.

[@isbestlizard]

It's easy to detect absolute acceleration, just rotate your accelerometer. If you get the same reading, you're not accelerating. If it changes, e.g. from being positive, to being negative, you are. Since we can assume there is no evil demon that is watching you, and causing the whole universe to change its relative acceleration exactly in sync with your rotation.

[@tim40gabby25]

Hi. Could you expand on this?

[@wayando]

But is it possible to tell the difference between sitting in a rocket accelerating at 1G vs sitting in a planet with gravity of 1G?

[@ChristoffelTensors]

Can you formalize this mathematically? Saying it is one thing

[@cykkm]

@@ChristoffelTensors “Can you formalize this mathematically?” - Easy: _acceleration is a vector._

[@ChristoffelTensors]

@@cykkm Accelerating according to what?

[@frede1905]

I think the key to this issue can be found when you define spacetime and its structure. At first, you define spacetime as an abstract real smooth 4-manifold. So far, so good. There's currently not much we can do in this spacetime. But then you add another assumption, namely that spacetime can hold a smooth Lorentzian metric. This is the key. For given this metric, you then find the coordinate chart that corresponds to a Minkowski metric. That then defines what you call an inertial frame (well, in general, you can only find a chart that is locally inertial, ie. there's a point where the metric is the Minkowski one, and the derivatives of the metric are zero. But the idea is the same). If there are many smooth Lorentziab metrics on the spacetime, then you simply choose one of them. That then defines a convention for what you call an inertial frame. You could choose any of these metrics, and define an inertial frame relative to it. It doesn't matter which one you choose.

[@WSFeuer]

Those are all mathematical descriptions, none of that is helpful. You want to describe reality as a four-dimensional manifold? A manifold is essentially just a collection of points. What are points? Just throwing out mathematical jargon without any idea of how to correlate it back to actual physical pictures, is not physics. In fact, it demonstrates you don’t understand physics at all.

[@frede1905]

@@WSFeuer Note what I said about being able to choose any of the smooth Lorentzian metrics on the spacetime. What Einstein essentially did in his 1905 paper on special relativity is that he chose the metric so that light would always travel at the speed of light c in all frames with the Minkowski metric (ie. so that light would travel along null curves according to the chosen metric). This means that all inertial frames measure the speed of light c, which of course is his first postulate of special relativity. Hence the metric was chosen with respect to something real, concrete and physical (namely light), thus addressing your objection.

[@frede1905]

@@WSFeuer Something related to all this is the problem of synchronization in special relativity. Einstein had to invoke a special kind of synchronization convention in order to define what it means for two clocks at two different locations in an inertial frame to be synchronized. This also relied on using the motion of light.

[@braden4141]

​@@frede1905could the choice of Lorentzian metric even with the restriction of the speed of light change which frames are inertial or did he prove with the speed of light restriction that it is independent of the choice of metric.

[@frede1905]

@@braden4141 I am not sure what you're asking. Are you asking whether the choice of metric is unique once you've chosen it so that light rays travel along null curves (ie, so that they travel at the speed of light in inertial frames)? Well, no. Any "conformal transformation" (which essentially means a kind of rescaling of spacetime) of the metric would also do. But I'm sure you could use whatever physical quantities or laws of physics that are not conformally invariant to restrict the metric further. The point I was making is that I imagine that one can use physically measurable things as a reference to define an inertial frame. This makes sense intuitively; an inertial frame is roughly supposed to be a frame such that the net force acting on it is zero (so that it's nonaccelerating). But how do you know what a force is? You'd have to refer to the laws of physics to describe it. The approach I take is to simply go the other way around; use the laws of physics, or the behavior of physical things (like light) to define what you refer to as an inertial frame. Anything at rest with respect to that frame is then defined to be nonaccelerating. By the way, note the use of the word "essentially" in my last comment. Einstein didn't describe any of this explicitly in his 1905 paper, and so you won't find it. This is sort of a reinterpretation of what he did in 1905, given the machinery that we know now (with metrics and so on) of the mathematics of spacetimes (which Einstein obviously didn't know at the time).

[@DemonetisedZone]

🏆 Best KZbin Physics Channel No doubt!

[@AntiCitizenX]

You seem to have a bizarre fixation with this idea of absolute acceleration. That's not really an issue, and anybody who tells you otherwise probably doesn't understand relativity. The magnitude of acceleration is relative, sure, but the fact that it HAPPENS is not. All observers in all inertial frames of reference can agree upon who is in a state of acceleration and who is not. I'm also wondering why you seem to ignore the idea of a spacetime interval. One of the greatest triumphs of special relativity is the notion that spacetime is definitely absolute. All observers in all inertial frames can universally agree on the magnitude of the spacetime interval between two events. So if you really care about "absoluteness" in your theory, then there it is.

[@WSFeuer]

“Anyone who tells you otherwise doesn’t understand the theory”? So Einstein also saying absolute acceleration is impossible means he doesn’t understand the theory. Ok cool, guess he didn’t understand the theory he invented, but you do. You must be a real genius. I bet you’re like a super smart professor and everywhere you go everyone is always impressed by your caliber of intelligence and logical reasoning skills.

[@AntiCitizenX]

@@WSFeuer Did you even read my comment? Let me say this again: 1) The magnitude/observed acceleration is relative. No on denies this, and nobody cares. 2) The fact that one observer is accelerating while others are not is NOT relative. Do you see the difference? The author is obsessing over something that no respectable physicist cares about, including Einstein himself, if you actually bothered to read his paper.

[@zemm9003]

​@@WSFeuerEinstein didn't say that.

[@zemm9003]

​@@AntiCitizenXprecisely he didn't care about any of this stuff in his papers about General Relativity. It concerned him where inertia comes from. He considered its origins analogue to a sort of aether but not the old absolute reference frame.

[@destroya3303]

@@zemm9003 "One would try in vain to explain...the pure and simple acceleration of a body. One would succeed is defining only the relative acceleration of bodies" That's from the paper cited in the video. Acceleration definitely matters in SR. It is the only way that relativists can claim time dilation equations only work in one direction to slow down clocks. If everything is relative, the effects must be symmetrical and thus only observed in each frame.

[@justaguy3518]

On the spring example, I was thinking no calibration is needed for you to detect the presence of an aceleration as calibration helps you to measure the value of said acceleration, but the value doesn't matter if you're only interested in determining whether or not there is some aceleration. But then something crosses my mind: when everything is accelerating together, there's no way to detect the acceleration. If the spring is also acelerating with us, we won't be able to use it to detect our acceleration. So I think I got your point: we can only detect our own aceleration by comparing ourselves to something that's not acelerating and, thus, aceleration is relative. Many people here is arguing about acceleration being a measurable property - and, therefore, absolute - but I think it's because it's generally very easy to find an inertial frame, so we assume we'll always find one. But what if we are all under a force making every single particle accelerate together? How would you find an inertial frame to compare to? I think Dialect really has got a point here.

[@benjamink2398]

No... acceleration is a vector, so if you calibrate a spring scale within an accelerated frame, and then you simply flip it over, it will immediately change shape under the very real acceleration in the opposite direction, clearly demonstrating that you've calibrated it in a non-inertial frame. This seems a way harder problem to solve for the Machean than justifying c being constant, imo.

[@shreyansengupta2594]

@@benjamink2398 You know right, you are not allowed to touch. No tampering with the system. Even if you don't flip but just touching the system, you will know whether you are in acc frame or not. So think you are just a pair of eyeball given to observe nothing more.

[@placeholder3907]

@@benjamink2398Under truly uniform acceleration, the spring scale is not deformed from equilibrium. Think of it as you would gravity, in the classical sense. So flipping it over, it’s still not deformed from equilibrium. I disagree with some things in this video, but this is not necessarily one of them.

[@justaguy3518]

@@benjamink2398 I'll give you a better example: imagine there's only one particle in the universe. How would this particle determine whether or not it is accelerating?

[@justaguy3518]

@@placeholder3907 same for me. There are things I disagree, but they really have a point on that

[@collindamskov]

My impatience makes me wish I had discovered this channel after conclusions are presented, not before!

[@dialectphilosophy]

Think you'll be pleased with what's coming in the next few months!

[@jonathancharry4418]

It seems Einstein’s view on the ether are subtle. The most generous way I can put it is that “Einstein believed in the ether” is correct if by that you mean “Einstein was a substantivalist”. But it’s still (by his own admission) not like any other kind of medium. Ether is basically just…spacetime. Interestingly, in the case of SR, there are letter between Einstein and Lorentz in which they seem to agree that the ether hypothesis is correct, insofar as “ether” is another word for “empty space”.

[@pwinsider007]

@@dialectphilosophy this problem is nobel prize winning.

[@X-boomer]

@@jonathancharry4418 the difference between relativistic spacetime and the aether is that the aether requires notions of absolute position and absolute velocity. Relativistic spacetime has only relative position and relative velocity but absolute acceleration. Relativity is telling us that position, separation and duration aren't fundamental. Instead, the fundamental components of reality are to be found in something like Penrose's Twistor space.

[@pwinsider007]

@@dialectphilosophy. @dialectphilosophy kzbin.info/www/bejne/g5OkaYKYYtWSps0 This person is falsifying special relativity by saying that Einstein ignores optical laws in his train thought experiment.roast him badly.

[@juliavixen176]

There's a third possibly, which Einstein and Poincaré already explained 120 years ago when creating the "Theory of Relativity" : Inertia comes from confinement. Remember all that E=mc² stuff? Ask yourself: Why does _anything_ travel *slower* than light? I'd elaborate, but I'm going to bed now. So, I'll write more when I wake up. Basically, proper acceleration of a rigid object is like the front of the object moving relative to the back of the object.

[@marccawood]

Time is not relative- it just looks like it is. Clocks or other measuring devices run slower under acceleration or gravity does not mean Time is flowing differently. It means we measure time differently. Measurements are not reality, they are representations of reality based on assumptions. Measured time is relative.

[@drossonero7595]

Time ain't relative, a second is still a second no matter the speed, saying otherwise challenges the basics of logic

[@Andrew-vz3qk]

You should look at relative simultaneity. If two events occur simultaneously for one observer, they will likely not be simultaneous for another with a different frame of motion. There is a solution to the twins paradox that doesn't rely on acceleration.

[@yannstaquet5522]

@@drossonero7595, time being relative doesn't mean a second is not a second. It means that person A may say that 2 seconds have passed between event X and event Y, while person B may say that 1 second has passed between event X and event Y

[@drossonero7595]

@@yannstaquet5522 you basically gone from time being relative to time being fake news. You're completely wrong, relativity claim that a second will be much longer if you're running close the the speed of light, and it will be a negative second or even negative millions of years of you exceeded the speed of light

[@yannstaquet5522]

@@drossonero7595, It's not seconds that will be longer. It's that there will be more seconds between 2 given events. Same thing for length contraction. A meter is a meter. What happens is that a body in motion relative to you will be contracted from your point of view in the direction of motion. So there will be less distance between its two extremities.

[@aniksamiurrahman6365]

Calibration is only required to accurately measure how much acceleration there is. Detecting the presence of acceleration doesn't need calibration. And this is a fundamental flaw in this video that puts a lot into question.

[@almightysapling]

Yeah, this is pseudo science garbage. Part of a larger endeavor to "question" sound science in order to break social trust in academics.

[@alekisighl7599]

I think you miss the point. Calibration here doesn't refer to measurement, rather the a priori knowledge of how the spring behaves in an inertial system. The only problem is.... you define an inertial system by looking at springs(absence of acceleration). Thus leading to a circular argument.

[@zemm9003]

Precisely.

[@zemm9003]

​@@alekisighl7599nope. You define inertial as being in free fall. This is the whole point behind General Relativity. Inertial frames are precisely the free falling frames. Obviously you would have to postulate this fact. Then check it vs. observation. So far experimentation agrees. Could there be other explanations? Sure but this one is extremely simple.

[@xSnowscopes]

​@@alekisighl7599ok i see, so i could define inertial as what we observe on earths surface at sea level. then i say ok spring deforms this much means no acceleration because inertial. also apple falling means no acceleration because inertial. apple falling is just because thats what they do. and then if i go anywhere else in the universe where acceleration is different, which is true even for higher elevation on earth, i say ok this frame is longer inertial because the spring is different and the apple falls at a different speed. and i would not rather choose something as an inertial frame where things dont randomly fall for no reason and which can be observed in alot more places in the universe than just at places with specifically 1G of force acting on you? i mean yes, you need specifically 0G for what we defined as inertial but you find that anywhere in space and while falling on earth... and the apples falling thing, still, how do you explain that? i dont fully understand this part of the video

[@raiangw]

Hi, I really like your videos, you are one of the few channels I what every video as soon as it is available :) But I have to disagree with you regarding the issue with calibrating the accelerometer. Taking as exemple the box with springs described in 6.35min, it is completelly possible to completelly build this accelerometer inside a accelerated referential frame, calibrate it there and still have it displaying the correctly that you are not inertial. For that you just have to check if the 6 springs inside the box are identical. To do that you just have to put the 6 of them side by side and check if: 1- They all have the same length L 2- They all have the same deformation DeltaL for the same external stimulus you apply on them. (They dont even have to be a "linear spring"). Of course, it is important to make these measurements with all springs pointing in the same direction/being side by side. Or you could also make sure to build them from the same material and that they have exacly same shape and measurements. But anyway, once you are sure that the springs are identical, when you assemble the accelerometer, it will "point" in the direction of acceleration, even if you checked their "identicalness" in a accelerated frame. What I will agree with you, is that the actual value of acceleration will indeed depend on the calibration (if you measure your DeltaL of check 2 in the direction of the acceleration it could be different than at an angle for example). But such accelerometer would only show 0 for a inertial observer. Also, as other people said, you can also rotate it in our hands once assembled as an extra check/test. Such accelerometer would always measure the "proper acceleration" (scalar value, independent of reference frame), and it is also a local measurement, as you can build it as small as you want, One of my university teachers would call it an "honest accelerometer" and he would define inertail reference frame as a frame where such accelerometer measures 0. Likewise he also would define time as "what an "honest watch" measures" with similar checklist to identify an honest watch.

[@imwelshjesus]

I could never understand ether either.

[@shaunmodipane1]

How I like to think of this, imagine you are in an accelerating frame, but you did not know because of reason X. So now you build your accelerometer with your process, making sure that the mass is in the center/equilibrium. Now you place your accelerometer in a "true inertial frame," now your accelerometer won't be at the center anymore. Then you are left with thinking that the "true inertia frame" is accelerating.

[@raiangw]

​@@shaunmodipane1 Yeah, that was the point of the video as well. What I am trying to argue is that it is possible to circunvent this problem by making sure the 6 springs used to build it are identical, and you can do it even in a non-inertial accelerated frame. For example, you here on Earth, if you put all 6 springes upright side by side on top of your tables and: 1- measure they all have the same size 2- put the same rock on top of all of them and check if the contraction is the same. If both points are match then when you assemble it, it will point down toward Earth (I.e. identifying correctly that you are not inertial ), even though you calibrated it in a non-inertial frame. Of course, if you actually want to calibrate it properly to identify the actual value of your acceleration you need more tests than those 2, but they are enough to identify that you are not inertial

[@rogerfroud300]

Isn't rotation absolute? I'm not a phsyicist, i'm an Engineer. it seems to me that a sphere tries to stretch perpendicular to the axis of rotation. This is always positive, and could be measured. Rotating something slower in that axis reduces the stretch until you reach a minimum at which point you know you're reached absolute lack or rotation. I'm sure this must be wrong, but in what way?

[@heinrich6294]

There are more options. Another option is that you change your inertial frame relative to your last inertial frame. Therefore you change it relative to yourself so a speed change would be instant. If you do not change your inertial frame you would be standing still relative to your last inertial state so you will not change your speed. In my little theory time helps out.

[@AndrewBrownK]

My mind goes this direction too. It's time to stop thinking about particles and start thinking about world lines. This explains the calibration reference frame. It's not about the reference frame, it's about the past of the accelerometer. This line of thinking also might indicate that "not every electron is identical" so to speak because each particle has a different world line which is hidden state that can still affect the present, isn't simply erased by being in the past.

[@MAElbashir]

That's a great way to think about it for a single reference. But when you add another reference like in the twin paradox situation, you can't decide which inertial frame is stationery and which is moving.

[@Obiekt219R]

@@MAElbashir that doesn't matter - it's the measured difference between 2 states of a frame. Observers A and B may disagree on the velocity of C at times t1 and t2, what's important is whether they agree on the *difference* v2 - v1.

[@Obiekt219R]

That's exactly how I've been thinking of it. It's all about measuring and comparing differences between states, not the values at each instant in isolation. My proper acceleration is an absolute change between my own 2 states that all inertial observers would agree on - they might all disagree on the start and end values, but not the difference.

[@MAElbashir]

@@Obiekt219R they do agree on the difference v2 - v1 but they don't agree on to whom is this difference is added to. From each of their prospective they could be stationary and the other one is moving.

[@nathangonzales2661]

The title of this video says enough for me.. Even if your hypothesis were internally consistent, to peoclaim your MODEL is the true reality, may indicate a deep misunderstanding of science.

[@sarahbell180]

Now I'll try my best to be concise (not my forte but definitely something I need to practice). First, I want to critique the premise. First, it is tricky to analyze the views of Einstein through this one paper since his views adjust over time. It is extremely prudent to mention 1914 was a time he was still running in circles and believing generally covariant theories weren't possible because of the hole argument. What's funny is that after a simple but profound realization, he quickly realized the generally covariant theory. After that, he had to do some reorganizing of his founding principles and his views would change. Most notably, he had to tear from the idea of 'coordinates' being of intrinsic physical meaning. This brings to the second point that Einstein's word, even on relativity, is not gospel and in fact is highly idiosyncratic. It shouldn't be confused with the modern viewing, which I argue gives a quite simple resolution in the most obvious place to miss. To see what this is, let me emphasize something about the nature of your critique. Every critique is framed as to why general theory of relativity does not obey relativity and implicitly treating that as a problem because of that assumption. This critique does not ask *why* such a manner of relativity is justified from core principles of epistemics and to be expected in a logical manner of a sensible theory. To be perhaps more blunt: the general theory of relativity may not obey this sense of relativity. Then I ask: why should it be expected to? Why is it a defect? What aspect of epistemics and logic make this a necessary expectation? You treat Einstein reversing his stance as a failure of GR to incorporate relativity, when to me it reflects a reconsideration on its exact nature and the need for it. I think a very careful, critical evaluation of this fact reveals a, in hindsight obvious, conflation at play. Let me state what is really needed. We need a means that, as an observer, to have empirical determination of various physical quantities and mechanisms around us in a given model, and that given model able to produce only from those experimental pieces alone a description of the physics. We can not presume any observer any more special in its chosen model-all differences must need to arise from something that itself is measurable with only assumptions of the model. Since otherwise, something non-measurable, like choice of observer, would lead to the need of different scientific theories to describe the same thing-a 'multiple reality' description of physics that is obviously absurd. ie, its a principle of 'ontological non preference', not of 'relativity'. This is my attempt from looking critically at the matter at why such a kind of principle is an expected thing. This principle is often assumed to imply the principle of relativity. To see the difference, let us note that in the principle of relativity, we expect a frame to be attached to each observer, with an implicit experienced physical reality of the space and time extending through out based on unambiguous measurement. We fill this world with agreed on physical quantities (in our model) and now presume the laws of physics when considered over all physical quantities to be obeyed. Whats problematic is how it seems to present the question of what is physically real as implicitly obvious. That attached to 'you', the observer, the time you can only empirically sense with a clock with you somehow extends to the rest of the universe. It does not follow from the minimal expectations of empirical expectations nor of logical consistency. One can see why this unjustified (albeit natural and sneaky) viewpoint would lead to perceived problems of relativity. To see what I mean, lets suppose that view and we are in a 'inertial' frame that begins to accelerate. Then, accordingly, g_uv goes from 0 to non-zero everywhere. To you, this wouldn't be properly 'physical' as it would propagate instantly everywhere with no physical source, seeming to be more implicative of it being from our frame as the cause. This is half true. Let us look at this scenario very carefully. First, were I just me in space with rocket boots, only *I* would accelerate. There is no distant part of my 'frame' that accelerates, not any one *I* can meaningfully measure. Therefore, should I accelerate, the only presence of the gravitational field that is meaningful to me is local. Once again, your implicit assumptions of physical reality are at fault. A scenario that may be imagined is a rocket ship with clocks and rulers throughout it. If I'm in the cockpit and accelerate, we want to imagine the entire body it accelerates. But, this is not the case: it is only by structural stability that the rest eventually accelerates, by propagation at speed of sound to the end of the ship. Thus, there is no 'instant everywhere' influence. *I* could perceive the scenario as a local gravitational field propagating throughout and expanding more steadily. Importantly, the bigger the ship, the longer it takes to accelerate and so the more global the frame, the more 'disconnected' distant bits are. We might imagine to synchronize clocks and time our thrusters. But now notice: this relies on something outside *my* mere empirical, physical experience, but the chosen correspondence to the other frames to accelerate. Therefore, the *real* cause of the global, instantaneous gravitational field is how we chose to define a global accelerating frame in the first place. Here is then the main point: this necessity of correspondence means there *is* no implicit physical frame attached to an observer that reaches out globally, one that the locally existing *me* can find through pure experimental processes purely by myself. Thus, the assumption in this principle of relativity is flawed and when we get rid of it and couple the need of frame-to-frame correspondence as itself part of our needed empirical testing, can realize that now, all differences can be accounted for as purely empirically measured things by me and everyone else involved. In this manner, I simply empirically measure how my synchronization goes with local observers to get my part of the metric g_uv and use it to account for a description of physics holding no special emphasis to any observer because anyone could have found it in the same way using the same models and empirical apparatus. This applies to Newton-Cartan theory and explains Kretschmann's criticism: Einstein was using a wrong framework that needed that principle: when it was done away with, it was realized there is no problem nor is it something special to relativity. Relativity just forced the hand. When these things are conflated, things become quite confused as g_uv lives a dual life of acting as a physical field as well as empirical correspondence between observers on clock and distance measurements, and thus the question of what 'is' physical and what isn't. I look forward to your response but I really want you to very carefully consider the second paragraph.

[@maximusideal]

Well if nothing else, I read this and found this to be very interesting. I do hope Dialect considers this carefully!

[@bmortomorton]

Hell yeah!!!!

[@dialectphilosophy]

Hi Sarah, glad to see you're back again and still following the channel! We're not sure quite what the thrust of your objection is here, but we'll attempt to address your points the best we can. In terms of Einstein's 1914 paper, this was concurrent with his issues regarding the hole argument; the resolution of the hole argument wasn't that coordinates are meaningless however, it was that they DID have to be referred back to physical entities like clocks and measuring rods (and implicitly, inertial frames). Coordinates always have meaning (just not always the same meaning between different frames), but Einstein's eagerness to relativize all motion often mislead him on that point for quite some time. You may not think that Einstein's reversal on the ether stance is significant, but we would strongly disagree. He was the founder of relativity, and his theory won out precisely because it did away with the ether. To reverse his stance was an admission that he hadn't gotten the philosophy right back in 1905, and since he contributed almost nothing to the mathematical formalism of special relativity, the philosophy was essentially all he contributed. Again, this makes sense as his philosophy was only developed for constant velocity-motion, whereas General Relativity forced him to confront the problem of general motion. Lastly, your critique of the accelerated frame is certainly not without merit. To built a true accelerated frame would require infinitely rigid bodies, which is impossible. However, you again miss the thrust of the argument -- watching the walls of your rocket ripple with compression effects doesn't prove that you are accelerating, especially since if you took your rocket frame to BE inertial, it wouldn't ripple by definition, and instead you would see all the space around you rippling. Observations of acceleration are, as Einstein said -- and we find ourselves tirelessly repeating -- only ever observations of relative acceleration.

[@sarahbell180]

​@@dialectphilosophy Honestly, I think this wildly misses my point and why I mention certain things so here it is again. Starting from minimal expectations of epistemics and logic, why exactly is relativity necessary, and what does it mean in that deduced context exactly? The crux of your critique is that general relativity is defective because it does not follow a presupposed form of relativity, when I think we should first reconsider on what relativity means and why we presuppose it in that form as needed. This is why I think you're confused, because you keep trapping yourself in some implicitly assumed expectations. What is the assumption I identify you to make? Its the notion of an implicit relative physical reality to an observer. In the special relativity viewing, the coordinates (x,y,z,t) represent a physically real, unambiguous, measurable perspective of the world. Space and time are physically real in a relative way attached to an observer, and there is no absolute 'underneath' thing to it. My argument is this perspective is wrong especially when it comes to general relativity, and it is worth some more careful, nuanced revision. By trapping yourself in this view, you perceive a certain form of physical relativity as needed for consistency where I argue it isn't. In fact, because this assumption I identified completely breaks down in general relativity, I argue it isn't even clear what 'physical relativity' is supposed to *mean*. I can tell you have this view because of the way you talk about an accelerated frame 'attached' to the person physically accelerating, as a 2D grid spreading out going with the acceleration. Never is it asked *what* an accelerating frame means, how things *actually* look to my epistemic perspective (they would only observe things only locally), how one would operationally go about measuring such distant times. In fact, there is a great level of ambiguity here on how to obtain one. My point here is clear: you argue there is no identifiable physical cause to the gravitational field in an accelerating frame, and that the global instantaneous emergence of such a field coincidental with our acceleration makes our frame preferred. I argue that our coordinates do not reflect physically measured values and therefore epistemically we are allowed to detect a difference simply by observing different measurements to that of an inertial frame (this can simply amount to comparing clock rates and test of synchronization). There is no epistemic or logical difficulty. By getting rid of that assumption, we can take things as they are.

[@jethomas5]

@@sarahbell180 As I understand it, you are saying that we have the math to make valid predictions about measured situations. For example, the movement of charged particles relative to each other. Since we can do that, there's no need for interpretation. Just accept that what the math predicts is what happens, and let it go at that. If we find circumstances where the math makes wrong predictions then that's something to deal with. However, all of us start out with more-or-less newtonian assumptions. A world with euclidean distances and the same linear time for everyone, etc. But almost all of our experience is with electromagnetic force, and it just doesn't work that way. So if we could find an interpretation of the way things work that is simple and clear, that would be useful. Maybe not useful for calculating the math, but useful for understanding it. What we have is not that. We have stories about putting a 40 foot pole in a 30 foot barn with the doors closed, and twins that don't just see each other as different ages when they pass by but they shake hands and one of them is 50 year older, and the explanations from people who think they understand it, contradict each other and don't make sense. If we could get a simple story that makes sense that would be an improvement. Even if it didn't affect calculating the right answers and just accepting them,

[@gniccolai]

The fact that every observer from any reference frame sees the light traveling at the same speed is not an axiom. It's a consequence of 1) the observation that maxwell equations are independent from the reference frame and 2) the space-time geometry. In particular, about 2, light travels at an infinite speed; it's the shape of space-time that causes the observers to see it moving at a finite speed because every point in space sits in a different time. The "observed" speed of light is the time gradient, or differential, across different regions of space. We sit in a space-time that is one second away from the moon; light can travel there I'm an instant, but since the moon is one second away in time, every observer will perceive light ad traveling for one second between the earth and the moon. Given that, assigning light a finite speed (rather than considering the space-time geometry of the universe) helps with some calculation and thought experiment, but that is not how things work in reality.

[@LeeCarlson]

And having "done away with Aether" we needed to create the concepts of Dark Matter, and Dark Energy when we recognized that the universe was not behaving congruently with Einstein's math.

[@stanleysheppard8464]

Exactly. The "missing mass" and "missing energy" of the Universe that were called "dark" is the aether out of which everything is made, including atomic and subatomic particles which are the concentrations of denser aether forming toroidal spinning structures governed by electromagnetic effects.

[@antonk.653]

​@@stanleysheppard8464 Crackpot theory, just like string theory. You have absolutely no (experimenta) proof of anything you said.

[@horseios3655]

@@stanleysheppard8464 K buddy enough screen time for u go touch some grass

[@seinfan9]

Ya bud. Tuch grash. U tink u be smurt? Saiyance iz kang.

[@Dismythed]

I finally proved just yesterday (after 10 years of careful study and exploration), using a Minkowski time-space diagram, that absolute space is localized to any massive body. The change in distance between bodies is acceleration. Therefore absolute space itself exists, but is relative and local to all other massive objects. If all bodies in the universe shared the exact same position relative to each other, then absolute space between bodies would be achieved, but the universe would cease to exist because all particles would stop. Absolutism is not about the movement through a void of nothing, but about relative positions. The mass itself creates the tempero-spatial acceleration within its frame as it changes in relation to all others, with preference to local objects over distant ones. Thus it itself becomes absolute to any other massive object connected to it. (Earth is an absolute frame. It is the frame by which we measure all other frames. But so is our own body an absolute frame. All other things are relative to it. Any one electron is an absolute frame to which all other things are relative.) Why? Because a void doesn’t care whether objects are one Planck length apart or the entire universe apart. What does care is how many objects exist between them. This creates relative time and distance. Waves are a fundamental effect of objects moving relative to each other. That is why photons in a vacuum move at the same velocity regardless of the frame of the observer. The wave is what changes. It is the compression of distance relative to all other objects. The entire universe is localized (not infinite) and within it are things that are even more localized. This creates an inverse proportionality. The Minkowski diagram reveals that there is an as yet undefined law of physics that says all things that exist must move; that a thing that does not move cannot exist. Thus the universe could not exist without being both finite and every object within it constantly in motion. Neither time nor space exist without changes in distance between multiple objects. If an object spins in perfect nothingness when no other object exists, is it really spinning? Answer: No it’s not. It has no spin, velocity, charge, wave or any other tempero-spatial attribute without the existence of other objects. The universe is not spinning because there is nothing to compare it to. (A multiverse cannot exist because a universe, by definition, is everything that exists. If our local bubble were only one of many, they would all still share relativity in the void between them because the void doesn’t care and ours would be the absolute frame to us, and yes, it would spin relative to others.)

[@FensterwischerX]

Hey some quick thoughts 1. First you say that an absolute space is inherent to every massive body, later you say that everything that exists moves. What do you mean? 2. Movement doesn't need acceleration, it can also just be relative velocity. 3. First you say that absolute space does exist, then you define absolute space as something that does not exist. 4. The fact that everything can be set as an "absolute" reference point seems to make everything arbitrary and relative instead of everything absolute. 5. A spinning object experiences forces. Even if nothing else exists. Therefore it is given that it spins. 6. A definition of universe that I like is: Everything that we can possibly interact with/ can interact with us is the universe. According to this definition there may be stuff further out there but it can not matter for us.

[@daltanionwaves]

The car on the aircraft carrier was hilarious. Perfect timing and delivery

[@davidgould9431]

2:00 I probably have something horribly wrong, here, but I thought Einstein's initial premise was that no inertial observer has a privileged position over any other. Then he looked at Maxwell Clerk's equations of electricty and magnetism. The speed of light drops out of that and he realised that you could measure it by doing experiments with electricity and magnetism. To keep to the "no privileged position" axiom, that speed would have to be the same for all inertial observers. It boils down to the same thing, but I thought the constancy of the speed of light across inertial frames of reference was more a consequence of the "no privileged frame" axiom than an axiom itself. Edit: btw, only just found your channel and am doing catchup. Super-impressed! The above is not a criticism: more my wondering whether I've been misunderstanding it.

[@JoeWithTheHoesBiden]

I believe you mean that no observer has a privileged position over any other. Inertial observers do not exist in Einstein's word, only inertial frames.

[@davidgould9431]

@@JoeWithTheHoesBiden Yes, I was amazingly sloppy at first but got it right in paragraph 3. I think. Anyway: thanks for the heads-up.

[@RobertGeez]

An acceleration is required to change your position along the time dimension. Energy is required to do this. No object actually moves when you observe it independently of all other objects. Differing constant velocities is just a measurement of where that object lies along the time dimension with respect to others.

[@hoon_sol]

You don't get it at all. When you accelerate, you could equally well say it's you remaining at rest and the entire universe accelerating in the other direction; but clearly it doesn't feel that way, so what gives? Nothing you say answers this question. Mach's principle is necessary to understand why that happens. Also doing away with the nonsense that is relativity theory of course, but that comes later.

[@RobertGeez]

Acceleration does not equate to movement, only an external force acting upon an object. That force is changing your velocity vector within the time dimension.

[@hoon_sol]

@@RobertGeez: Again, you still aren't getting it *AT ALL* and it's getting almost embarrassing to have to point it out. The entire point is that under the assumptions of relativity theory *THERE IS NO WAY TO HAVE A PREFERRED FRAME OF ACCELERATION* at all; that's literally exactly the problem Einstein himself identified, and never managed to resolve at all.

[@herrroin6867]

@@hoon_solWho do you think you are?

[@HeribertMuermann]

@@hoon_sol As fat as I understood without a reference frame we cannot differentiate between gravitation and (other forms of) accelaration. Means the curvature of space-time makes the difference to a linear, not accelarated movement. If I were on an seemingly endless plain I wouldn't be able to say something absolut about my position. But I would still feel whether I moving an hill up or down. May be it's something like this analogy. But my understanding of general relativity is very superficially. Explaining it with my insufficient English is another problem. 🙂

[@maxtseluyko9588]

I have read Lindner's paper and encourage everyone to read it, irrespectively of whether you agree with him or not. There are several layers to Lindner's paper though: 1. Theological: "As a young man I discovered philosophy through the works of Ayn Rand. She asserted the primacy of existence ("Cosmism") over the primace of consciousness (spiritualism-idealism). I embraced Cosmism and began deprogramming myself from the spiritualistic doctrines that I had been taught". So, he thinks that his paper disproves God - and that is what he wants to do on theological level. 2. Than comes his philosophy. For some reason he thinks that subjectivistic philosophy (that states that there is no reality, only subjective illusion, that my mind creates the universe making the latter my fantasy) proves God and that objectivistic philosophy (that states that there is reality independent of me the observer) disproves God. Why he thinks it, i do not know. It is plain wrong. Neither does prove or disprove God. When he argues against Berkeley he disapproves specifically of Berkeley' concept that "God causes some bodies to tend towards each other, others to stay at fixed distances". Probably Lindner thinks that belief in God is based on believing that reality is inconsistent on its own and need its Creator to make specific Divine Interventions regularly to make this mechanism work. This is strange: an Absolute Power combined with Absolute Wisdom would surely create a reality that would be functioning without constant intervention. Even a mortal coder would do it. On the other side, let us compare reality to a car and God to a Mechanic. Neither functioning (that is: in no need of Mechanic's Intervention) nor broken car (that is: in need of Intervention) would disprove Mechanic's existence. So, 'tis strange to make such an argument in the first place. 3. That comes the scientific layer: relativism is subjectivism, therefore must be disproven. Ether is good because it makes the Cosmos, in which Lindner believes (as he stated), self-consistent. I know not why he prefers "Ether of the Cosmos" over "the Laws of Nature" to base his pantheism on. His Cosmos needs quantised unobservable Ether but he criticises Kant for his noumen. After Kant he springs immediately to Mach in his recount of the Enemy's philosophy. Shame Hegel is nowhere to be seen, since Lindner falls in the false dichotomy of "subjective observations" versus "Unobservable (but Objective!) Cosmic Substance". Hegel's dialectic would have probably cured him of such a fallacy (since Hegel finds solutions to all these dichotomies and paradoxes, proving them false). Lindner is a fun case of how to build a religious science.

[@maxtseluyko9588]

@@soopergoof232 I am Orthodox Christian.

[@MatthewDickau]

To everyone here, I suggest reading Tim Maudlin's book on the Philosophy of Physics: Space and Time. Brings some clarity and needed understanding to the issues presented here. Also John Bell's Lorentzian Route to Special Relativity is a must-read.

[@chrisoakey9841]

One of the problems is it doesn't work in reality of a globe. How can we be accelerated upward to feel gravity on each side of the globe simultaneously? Relativity suffers from the new age religion that we are the center of our reality.

[@felipescalisegaspar6801]

Dialect being dialectic! Definitely recommend David Bohm’s interpretation of space-time!

[@Pandaemoni]

In 1914 Einstein called out his own 1905 theory because the "Special" Theory of Relativity only applies to unaccelerated reference frames...i.e. to a special case. The General Theory of Relatiovity, published in 1915 does apply to accelerated reference frames, solving that defect. Einstein wrote a popular science book for non-scientists in 1961 ("Relativity: The Special and the General Theory-A Clear Explanation that Anyone Can Understand") explaining his theories in plain English and with some algebra. IIt's not going to enable you to find solutions to the Einstein Field Equations or general relativity, but it is a good read and from the man himself. I am not sure it's still in print, but a quick Google search shows that you can still pick up later printings (even in hardcover) for less than $5.

[@dukefleischer2604]

Einstein died in 1955 making it difficult for him to write a book in 1961. Perhaps it was 1916.

[@Pandaemoni]

@@dukefleischer2604 Yes, good catch, and I seem to have several typos... it was originally written in 1916. The third edition (1918) is available online here: www.f.waseda.jp/sidoli/Einstein_Relativity.pdf

[@destroya3303]

"The General Theory of Relatiovity, published in 1915 does apply to accelerated reference frames, solving that defect." This is a very hand waiving explanation that some people give. However, nobody shows HOW General Relativity makes SR applicable to accelerated frames.

[@TimothyOBrien6]

My personal feeling is that non-locality must be embraced, which resolves the need for an absolute universal frame of reference, and Bell's dilemma. I am working on a mathematical model in which non-locality is a natural feature, from which space and time emerge.

[@paulthomas963]

Like the quantum field? Which already produces C, T, and D. The "hidden" variables.

[@backwashjoe7864]

The number of videos this channel has posted in each year-long interval is (1 video, 4 yr ago), (3, 3), (3, 2), (4, 1), (8,

[@dialectphilosophy]

😂

[@QuicksilverSG]

Isn't there a third option for measuring absolute acceleration - with respect to an object's own instantaneous reference frame? This is by definition an inertial reference frame, and is uniquely specified for each object at any point in spacetime. Intuitively it makes sense. If an object's trajectory remains unchanged, it will experience zero acceleration, regardless of what occurs in the rest of the universe. But as soon as a force is applied to the object along any vector (with respect to its own degrees of freedom), it will experience a measurable acceleration relative to its own instantaneous frame of reference, again without regard to the rest of the universe.

[@facebooksubs9234]

Why does he refers to space time and motion in newton's laws absolute?aren't they also relativistic,i am confused.

[@QuicksilverSG]

@@facebooksubs9234 - Not sure which point in the video you're referring to, can you provide a timestamp?

[@ApexEater]

Why are we so afraid of absolute space? If you think of velocity as it's own dimension then it obviously has the limit of causality and everything in the universe is moving relative to the direction of zero velocity. This makes time paradoxes and time travel disappear and puts everything on a coordinate. Infinity doesn't have to be the answer.

[@thibautklinger5178]

Hey guys. I have thought about your example with the boat and the car. It reminded me of bells paradox. Even if both spaceships accelerate at the same rate( according to the resting observer) the see each other accelerate too because the string breaks. I will at times try to use rindler coordinates to plot the cars worldline from the pov of the shore. I love how you guys can make me think deeper about things.

[@reyco1982]

When in freefall the accelerometer says the acceleration is zero yet visibly accelerating relative to ground.

[@aangulog]

The quality of this videos is amazing, as a math major I really like the approach they take, not easy neither super theorical. It's really impresive the way this man can address this topics. I'm eager for more videos (specially the logic related ones), have a nice day and thanks for the upload!

[@hansolo9892]

yeah I am into mathematical physics. This style works for me too!

[@user-lb8qx8yl8k]

6:18 "Inertial frames are defined via an absence of acceleration." ??? An inertial reference frame is a coordinate system whereby the velocity of any free particle is constant. Put another way, the worldline of any free particle is straight in an inertial reference frame. Moreover, any reference frame, inertial or non-inertial, is independent of a particle, whether that particle is accelerating or not. A big misconception of SR is that there can be no discussion of acceleration.

[@hansolo9892]

@@user-lb8qx8yl8k You just explained the same thing. Why are you quoting stuff that isn't even wrong with your logic? Absence of acceleration = zero acceleration= constant velocity. (continuity is assumed.)

[@jacobm5167]

​@user-lb8qx8yl8k -- That's exactly what I wanted to say. I like dialect l, but I also think he's very wrong on this point. It's as if he's saying that every worldline within an inertial reference frame must be straight.

[@user-lb8qx8yl8k]

@@jacobm5167 -- I like dialect too. He demonstrates much knowledge. That's why it surprises me that he gets such a very basic point wrong.

[@EduIreland]

I am also missing something here. From my understanding, acceleration is proportional to a force being applied to the object - force is (at least locally) absolute, hence acceleration is absolute. Another way to describe acceleration is the rate of velocity change over time (dv / dt) and while velocity is relative, change in velocity is not. If one must describe acceleration to a reference, then the reference can be the object being accelerated itself - it is a local reference frame. Imagine you are in space, holding a bowling ball. No forces are being applied to you nor the bowling ball. You now just remove your hands from the bowling ball - which should stay in the same position in relation to you and become your "frame of reference". Now apply a force to your body (say, a jet-pack) for 1 second, that will make you accelerate, leaving the bowling ball behind - your speed in relation to the bowling ball went from 0 to, say 20m/s in 1 second - you accelerated (20 - 0) / (1) = 20 m/(s*s) and your speed in relation to the bowling ball is a constant (i.o.w. no changing) 20 m/s. If you apply the same force, in the same direction for the same 1 second, in relation to the ball you go from 20 m/s to 40 m/s - you accelerated (40 - 20) / 1 = 20 m/(s*s) - exactly the same as before. Rotation is just a special case where the acceleration is continuously changing direction, but the same experiment could be applied - if you are rotating and let a bowling ball go (without applying any forces), it will move away from you.

[@johngill2343]

This was once again quite excellent. For a quite excellent account of Einstein, Mach and general relativity model building I can highly recommend "The Geometry of the Universe", by professor Colin Rourke. He proposes the Sciama Principle as an axiom and also a basis for Mach's Principle. The inertial frame is defined by the distant rotating masses, since in the Sciama Principle, a body's influence on the surrounding spacetime drops off with 1/r, hence any such effect is dominated by distant masses. According to Rourke what confounded Einstein, was that de Sitter Space is a solution to his equations, with no matter, but a uniform negative curvature. The unique vacuum solution is the Kerr metric, which drops off as 1/(r**3). But space is not a vacuum, it's full of hydrogen and microwaves. It's not hard from here to see why the Sciama Principle should apply. All rotations are accelerations, and general relativity applies all rotations. Would love the opportunity to discuss Professor Rourke's work you.

[@inverse_of_zero]

After reading through the comments of this video, I am convinced that the *existence* (but perhaps not necessarily the magnitude) of acceleration is absolute. If we define an inertial frame to be one whereby (amongst other things) the geometry of compressible matter (e.g., a spring) is invariant under all possible rotations and translations, then it becomes abundantly clear which frames are inertial and which are not by simply checking for this invariance (or otherwise). A spring which compresses in one dimension but not in another (i.e., disobeys invariance of its geometry under rotation and/or translation) is a phenomenon which is agreed upon by all observers in the universe, including those that are both in and external to the (non-inertial) frame of the spring. Namely, invariance of Newton's laws under rotation and translation is a phenomenon agreed upon by all observers (as is also the constancy of the speed of light), and thus I can only conclude that the property of a frame being inertial or otherwise must also be absolute. I also don't follow (agree) with the (counter)argument that the requirement of invariance of spring compression under rotation is a subjective human construct. I mean.. sure, the postulates of physics and mathematics can be thought to be human constructs as we are the observers in our universe, but the point is, we have to start with a definition of an inertial frame, and we have done exactly that (implying invariance under rotation and translation), and, sure, we could have defined it differently, but that' s a moot point. Once we have made that definition, the fact that we observe a change in that definition, and that all observers agree to witnessing that change, indicates that one frame is inertial, and another is not.

[@thibautklinger5178]

If we have no way of detecting the ether other than some abstract link to acceleration to it how is it different than the notion of an absolute space

[@DingoHammer]

It seems like Einstein chose either over absolute space because he disliked either less that he disliked absolute space!

[@thibautklinger5178]

@@DingoHammer my question was directed to Dialekt. What would be the difference between a non detectable eather and an absolute space?

[@the11382]

I don't see how ether is different from an absolute space in general. I would like to be enlightened.

[@lairbox]

I was a very strong supporter of aether but it took me a looooot of time to get rid of it. I've found that the geometry of space as hyperbolic +round space could eventually give us a chance to define space and time as defined in classical Newtonian physics and return to a more simplistic way to see our universe. I'd like to discuss it whith whose are interested in the argument.

[@MrMoose1347]

I’m down. I’ve always been a strong supporter of looking at both sides while I never sat on ethers side I do know a great deal about its studies

[@rohitjohn6180]

For the spring calibration problem, wouldn't pointing the spring and 3 perpendicular directions give us some clue. Moreover, just flipping the position of the spring and mass give us some clue of the rocket's acceleration, unless it's accelerating because of gravity. So, unless we are dealing with gravity, we can detect acceleration using a spring and mass.

[@dannylad1600]

True, and it also applies to gravity as well. A simple spring sitting on a table in your house is going to experience some stress just supporting it's own weight since the table is accelerating the spring upwards through spacetime, resulting in a slightly shorter spring compared to if it went into freefall where it would feel no stress and be a bit longer.

[@rohitjohn6180]

@@dannylad1600 So would you agree that, if we are not dealing with gravity, we can in fact detect acceleration using a spring and mass?

[@dannylad1600]

@@rohitjohn6180, yes, as long as there's a resultant force involved there will be an acceleration.

[@rohitjohn6180]

@@dannylad1600 Doesn't that mean the topic discussed in the video is wrong. Or am I missing something?

[@dannylad1600]

@@rohitjohn6180 yeah the video's wrong.

[@jensphiliphohmann1876]

I don't fully understand why acceleration or rather _proper acceleration_ shouldn't be considered absolute: Unlike your velocity, you can feel it. You'll notice inertial forces if you are accelerated. What you don't feel is whether you already move into the direction of your acceleration and you're getting faster or if you move in the direction the inertial forces point and you're getting slower, or if you move perpendicular to the acceleration so that you only change direction.

[@karlbarlow8040]

Great video. But im unclear if you think the car on the ship is accellerating or that you are demonstrating that the observer proves that it isnt. Its a thought experiment that Galileo would have seen through. If the acellerations of ship and car are equal and opposite then they cancel for the car so that only the ship is accelerating. You are doing great work and definitely asking the right questions.

[@dialectphilosophy]

It was mostly intended to get people thinking about how motion always invokes a reference to what that motion is occurring relative to... so that what looks like acceleration to some could look like rest to others, but you are right that an accelerometer in the car ought to measure zero proper acceleration (if properly calibrated, of course).

[@karlbarlow8040]

@@dialectphilosophy Perfectly countering the ship's acceleration is the same as there being no friction between car and deck so from both the observer and the driver's perspective there is no acceleration. Thanks again for your thought provoking work.

[@pwinsider007]

@@dialectphilosophy @dialectphilosophy kzbin.info/www/bejne/g5OkaYKYYtWSps0 This person is falsifying special relativity by saying that Einstein ignores optical laws in his train thought experiment.roast him badly.

[@duckyy8655]

Nice video, but i don't understand why acceleration is absolute, you measure acceleration with a refference frame doesn't that make it relative, it's not a defect

[@carultch]

Assuming gravitational fields are out of the picture, you can measure acceleration without depending on outside reference frames. You simply measure what forces are needed to hold a body at rest, in your immediate environment. If no forces are needed, then you are in an inertial reference frame. This is precisely what accelerometers do, with a micro-electromechanical sensor. It's effectively a tiny mass on a spring. What you cannot do, is tell whether or not your apparent acceleration is caused by kinematic acceleration, or is caused by a uniform gravitational field. By general relativity's equivalence principle, these two situations are indistinguishable (being stationary on Earth, vs accelerating through deep space at 1 g).

[@fawzibriedj4441]

If the spring was in an accelerated rocket, we would notice it just by rotating the spring... Also, if we have an accelerometer with 4 springs for example, it would be easier to notice a problem even if we take a 180° rotation.

[@reyco1982]

Can also detect the rocket's acceleration relative to its exhaust.

[@satyajitsen8698]

Wouldn't you need springs corresponding to every possible orientation then? How would you ever have a sufficient number of springs then?

[@fawzibriedj4441]

@@satyajitsen8698 you don't need a spring in every direction as you can rotate your accelerometer and see the effect on a kind of (x,y) axis corresponding to the 4 springs you used

[@DemonetisedZone]

"Just by rotating" Rotating relative to what? How do you rotate something with nothing else to relate to other than the object? If there is nothing else to relate to saying "rotate it" because meaningless!

[@fawzibriedj4441]

@@DemonetisedZone in the context of the example I was mentionning, we would rotate it with respect to the rocket.

[@tymmiara5967]

*You don't need to have a calibrated accelerometer to tell that you are in a non-inertial frame!* Actually, you don't need to have an accelerometer at all. A mere acceleroscope (something that doesn't quantitatively measure anything, but qualitatively detects it) will suffice. You can have a crappy acceleroscope, say a ball in a cube mounted on six different springs of unknown properties (length, spring constant), and even that will work well enough. Just rotate the cube and see if the position of the ball relative to the walls changes as you rotate it. If it changes depending on the angle, you are accelerating. But by the way, your argument is even weaker given that there are good ways to make good acceleroscopes. Making identical springs is easy. If you mount the ball on six identical springs, then we don't even need to rotate our acceleroscope. It suffices that we measure the ball not at the centre of the cube. You say that claiming that acceleration is absolute even when everything that makes up acceleration is relative is problematic. But you are assuming that length and velocity "make up" acceleration. It need not be so. This is why instead of defining acceleration as a time-derivative of velocity, we should define velocity as a time-integral of acceleration. As with all integrals, you will get an unspecified constant of integration which is exactly why we cannot define absolute velocity. Everything makes sense. What's your problem?

[@PathfinderPhysics]

Love the time-integral argument. Yes, that's exactly the point! It's also obvious not all acceleration is absolute. Gravitational acceleration can be measured by external frames, but in the local frame it's free fall, thus no acceleration. GR deals with this problem elegantly with geodesics. Any motion deviating from geodesics is an acceleration. So what? It's the same as saying all observers agree on the sequence of events calculated with the spacetime interval. So what? Does that imply absolute time?

[@countwilly1]

Love this. Explanation for twin paradox never quite made sense to me, without some kind of absolute reference frame.

[@dialectphilosophy]

You'll enjoy our next video, stay tuned 😎

[@Robinson8491]

The rocket ship accelerates. It will always see a beam of light as c, it will never catch up. It does increasingly take exponentially more energy to accelerate for the rocket ship: will it eventually stop experiencing acceleration? If you increase the energy it will turn into a black hole due to mass-energy equivalence. So there actually is a natural limit to absolute acceleration: the maximum speed, which is the energy a black hole forms. So the energy of a black hole related to the energy to be put into the acceleration in a certain ratio is the benchmark for "your speed relative to" absolute space or the ether Which is why GR solves this problem

[@444haluk]

Acceleration is absolute. If you accelerate, and if you have a sensor on you, you can absolutely measure it. You cannot measure your velocity or position, you can only infer them by what is already accumulated (which is VERY relative). However, acceleration is absolute.

[@MichelleHell]

You can measure force, but the value of acceleration is relative to space traveled. F = mass(meter/sec*sec)

[@hoon_sol]

Yes, that's the point, you dingus. Acceleration is indeed absolute, and relativity theory is braindead nonsense with zero basis in reality. See: Mach's principle.

[@roseCatcher_]

When people say "acceleration is relative", they mean that magnitude and direction depends on the frame of the observer. The reason we find velocities as relative is because we established our frames based on their velocities. If we defined our frames based on their accelerations, we would've arrived at 'velocity is absolute"

[@ivoryas1696]

444haluk Wouldn't velocity _have_ to be absolute in *_some_* capacity because of the cosmic speed limit? As in a laser gyro could detect the light's change in velocity relative to one's self?

[@hoon_sol]

@@ivoryas1696: There's no such thing as any "cosmic speed limit". That's one of the innumerable faulty conclusions of the idiotic nonsense that is relativity theory. Also, even if you assume that nonsense to be true you're still not getting it, because that limit, under the postulates of relativity theory, is a limit that applies in any given rest frame, and thus velocity is not absolute (again, given those postulates, even though they're blatantly false).

[@josephjepson6756]

1. Make sure you are in a frame where the laws of physics that pertain to intertial reference frames are obeyed. 2. Now that you know you are in an inertial reference frame, calibrate your accelerometer 3. Now one has a way to measure “proper” acceleration which is frame independent Is it not enough to “define” inertial reference frames via the above step 1?

[@dialectphilosophy]

How do you know that the laws of physics are obeyed in a frame? You would have to have already defined concepts such as force, inertial motion, etc. as our laws of physics are all laws of motion.

[@Loxodromius]

First of all, congratulations for your great videos (all of them). I'm not a mathmatian nor a phisicist, just an engineer who loves science. I believe that all science starts by observing nature/reality. The fact that the speed of light is constant has been obseved by the Michelson-Morley experiment and by later and more refined experiments. So I don't think it can be called a postulate. It is an observed fact. About the accelerometers and it's prior calibration: if we are in apace, far away from any concentration of mass or energy and we are not using any form of propulsion, would it not be possible to calibrate the accelrometer in this way? I believe that although motion, velocity and speed are indeed relative, the only absolut is acceleration (and the force that mass objects feel with it). I believe that as far as possible things (teories) shoud be kept simple. Einstein said: time is what we measure with a clock and distance is what we measure with a ruller. He could also have said: acceleration is what we measured with an accelerometer (or a spring).

[@chadjensenster]

As a fellow engineer, I have some thoughts on acceleration. I posted the thoughts in my comment. Do you mind reading my thoughts and critiquing them for me? Thanks

[@markerena2274]

If you're in deep space far away from mass and energy, how would you know you're not accelerating or even moving if you have nothing to compare your motion to? How would you know for certain that this would be the "0-point" for acceleration?

[@Loxodromius]

@@markerena2274 because I would not feel any force. And because I would not be using any propulsion.

[@clevelandsavage]

The Michelson-Morely expiriment disproved the stationary ether believed at the time, but if they placed the apparatus along the Z axis, they would have gotten a positive result due to the bending of the light beam--of course now that will be interpreted as the "curve of space-time", but back then it would have been considered a confirmation of an ether.

[@cykkm]

@@markerena2274 “How would you know for certain that this would be the "0-point" for acceleration?” Because acceleration is a vector. It has a direction. It cannot be non-zero in all directions at once. And since direction breaks a continuous symmetry, viz. isotropy of space, by Noether's theorem there exists a quantity that is conserved in an unaccelerated, isotropic frame but no longer conserved in an accelerated, anisotropic one. The conserved quantity arising from the isotropy of space is the momentum.

[@SpotterVideo]

Is there an alternative interpretation of "Asymptotic Freedom"? What if Quarks are actually made up of twisted tubes which become physically entangled with two other twisted tubes to produce a proton? Instead of the Strong Force being mediated by the exchange of gluons, it would be mediated by the physical entanglement of these twisted tubes. When only two twisted tubules are entangled, a meson is produced which is unstable and rapidly unwinds (decays) into something else. A proton would be analogous to three twisted rubber bands becoming entangled and the "Quarks" would be the places where the tubes are tangled together. The behavior would be the same as rubber balls (representing the Quarks) connected with twisted rubber bands being separated from each other or placed closer together producing the exact same phenomenon as "Asymptotic Freedom" in protons and neutrons. The force would become greater as the balls are separated, but the force would become less if the balls were placed closer together. ------------------------ String Theory was not a waste of time. Geometry is the key to Math and Physics. What if we describe subatomic particles as spatial curvature, instead of trying to describe General Relativity as being mediated by particles? Quantum Entangled Twisted Tubules: “We are all agreed that your theory is crazy. The question which divides us is whether it is crazy enough to have a chance of being correct.” Neils Bohr (lecture on a theory of elementary particles given by Wolfgang Pauli in New York, c. 1957-8, in Scientific American vol. 199, no. 3, 1958) The following is meant to be a generalized framework for an extension of Kaluza-Klein Theory. Does it agree with the “Twistor Theory” of Roger Penrose? During the early history of mankind, the twisting of fibers was used to produce thread, and this thread was used to produce fabrics. The twist of the thread is locked up within these fabrics. Is matter made up of twisted 3D-4D structures which store spatial curvature that we describe as “particles"? Are the twist cycles the "quanta" of Quantum Mechanics? When we draw a sine wave on a blackboard, we are representing spatial curvature. Does a photon transfer spatial curvature from one location to another? Wrap a piece of wire around a pencil and it can produce a 3D coil of wire, much like a spring. When viewed from the side it can look like a two-dimensional sine wave. You could coil the wire with either a right-hand twist, or with a left-hand twist. Could Planck's Constant be proportional to the twist cycles. A photon with a higher frequency has more energy. ( E=hf, More spatial curvature as the frequency increases = more Energy ). What if gluons are actually made up of these twisted tubes which become entangled with other tubes to produce quarks. (In the same way twisted electrical extension cords can become entangled.) Therefore, the gluons are a part of the quarks. Quarks cannot exist without gluons, and vice-versa. Mesons are made up of two entangled tubes (Quarks/Gluons), while protons and neutrons would be made up of three entangled tubes. (Quarks/Gluons) The "Color Force" would be related to the XYZ coordinates (orientation) of entanglement. "Asymptotic Freedom", and "flux tubes" are logically based on this concept. The Dirac “belt trick” also reveals the concept of twist in the ½ spin of subatomic particles. If each twist cycle is proportional to h, we have identified the source of Quantum Mechanics as a consequence twist cycle geometry. Modern physicists say the Strong Force is mediated by a constant exchange of Mesons. The diagrams produced by some modern physicists actually represent the Strong Force like a spring connecting the two quarks. Asymptotic Freedom acts like real springs. Their drawing is actually more correct than their theory and matches perfectly to what I am saying in this model. You cannot separate the Gluons from the Quarks because they are a part of the same thing. The Quarks are the places where the Gluons are entangled with each other. Neutrinos would be made up of a twisted torus (like a twisted donut) within this model. The twist in the torus can either be Right-Hand or Left-Hand. Some twisted donuts can be larger than others, which can produce three different types of neutrinos. Gravity is a result of a very small curvature imbalance within atoms. (This is why the force of gravity is so small.) Instead of attempting to explain matter as "particles", this concept attempts to explain matter more in the manner of our current understanding of the space-time curvature of gravity. If an electron has qualities of both a particle and a wave, it cannot be either one. It must be something else. Therefore, a "particle" is actually a structure which stores spatial curvature. Can an electron-positron pair (which are made up of opposite directions of twist) annihilate each other by unwinding into each other producing Gamma Ray photons? Does an electron travel through space like a threaded nut traveling down a threaded rod, with each twist cycle proportional to Planck’s Constant? Does it wind up on one end, while unwinding on the other end? Is this related to the Higgs field? Does this help explain the strange ½ spin of many subatomic particles? Does the 720 degree rotation of a 1/2 spin particle require at least one extra dimension? Alpha decay occurs when the two protons and two neutrons (which are bound together by entangled tubes), become un-entangled from the rest of the nucleons . Beta decay occurs when the tube of a down quark/gluon in a neutron becomes overtwisted and breaks producing a twisted torus (neutrino) and an up quark, and the ejected electron. The phenomenon of Supercoiling involving twist and writhe cycles may reveal how overtwisted quarks can produce these new particles. The conversion of twists into writhes, and vice-versa, is an interesting process. Gamma photons are produced when a tube unwinds producing electromagnetic waves. >>>>>>>>>>>>>>>>>>>>>> Within this model a black hole could represent a quantum of gravity, because it is one cycle of spatial gravitational curvature. Therefore, instead of a graviton being a subatomic particle it could be considered to be a black hole. The overall gravitational attraction would be caused by a very tiny curvature imbalance within atoms. We know there is an unequal distribution of electrical charge within each atom because the positive charge is concentrated within the nucleus, even though the overall electrical charge of the atom is balanced by equal positive and negative charge. >>>>>>>>>>>>>>>>>>>>>> In this model Alpha equals the compactification ratio within the twistor cone, which is approximately 1/137. 1= Hypertubule diameter at 4D interface 137= Cone’s larger end diameter at 3D interface where the photons are absorbed or emitted. The 4D twisted Hypertubule gets longer or shorter as twisting or untwisting occurs. (720 degrees per twist cycle.) >>>>>>>>>>>>>>>>>>>>>>> How many neutrinos are left over from the Big Bang? They have a small mass, but they could be very large in number. Could this help explain Dark Matter? >>>>>>>>>>>>>>>>>>>>>>>> Why did Paul Dirac use the twist in a belt to help explain particle spin? Is Dirac’s belt trick related to this model? Is the “Quantum” unit based on twist cycles? ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ I started out imagining a subatomic Einstein-Rosen Bridge whose internal surface is twisted with either a Right-Hand twist, or a Left-Hand twist. The model grew out of that simple idea. I was also trying to imagine a way to stuff the curvature of a 3 D sine wave into subatomic particles. .

[@rouslanrouslan2677]

Great video! You should devote some time in a future video to cover both the history of the idea of a luminiferous ether, from Plato to the Michelson-Morley experiment and beyond and how the mechanics of the ether would affect relativistic calculations. That would make it much easier to appreciate the stakes of adding or removing the ether from general relativity.

[@otakurocklee]

Confused... didn't the Michelson Morley experiment show there's no ether?

[@MrMoose1347]

It did show no ether

[@angeldude101]

Accelerometers work (including ones built into our bodies), so there must be _something_ that they're detecting. Though from what I've heard, it's not really acceleration so much as _change_ in acceleration. But that would imply that even if acceleration isn't absolute, something else up the stack would appear to have to be. True relativity from what I can tell would require every derivative of position be relative, which doesn't appear to be the case.

[@APaleDot]

I think accelerometers measure the relative acceleration between the mass at the end of the spring and the object the accelerometer is attached to.

[@mcknottee]

"it's not really acceleration so much as change in acceleration." That is my understanding. Accelerometers, like a lot of measurement tools, are only measuring relative change. So they don't need to be calibrated to an absolute external reference frame. It simply isn't relevant. What matters is that the change is consistent (i.e. reproduceable and predictable). The only possible absolute reference frames I can think of are the Planck values for length, time, mass, and temperature.

[@carultch]

All you need to do is set up an accelerometer with two identical springs, opposing each other. Or 6 identical springs, if interested in all three axes. If your environment is accelerating, one spring will deform more than its opponent, and the accelerometer will detect acceleration. If your environment is inertial, both springs will deform an equal amount, and the accelerometer will detect zero acceleration. Footnote: yes, I'm aware that gravitational fields have the same effect, and we can't isolate those two causes of the accelerometer to detect acceleration. Assume gravitational fields are out of the picture, of this thought experiment.

[@TLMuse]

Relativity does not rule out *any* notion of an ether; it rules out an ether that behaves like a classical fluid. Quantum fields (the electron and photon (electromagnetic) fields, Higgs field, etc.) can be considered to be ethers, but of a type consistent with special relativity. Physics Nobelist Frank Wilcek has written about this repeatedly and eloquently. -Tom

[@dpt4458]

Science has been deprived in popular/general talks of adequate philosophical reasoning. I believe people have a distaste for it since they believe philosophy to be lacking any standard of rigour when the complete opposite is true. Nowhere else is there a higher standard of proof then in philosophy. Thank you for reviving the art of fundamental reasoning and by applying it to scientific theories. I think this sort of common ground between science and philosophy is awesome, philosophers being scientists and scientists being philosophers is how we got our most important advancements as a species.

[@MrFram]

In fact it the precise opposite - sciences have too much philosophy, and this is the source of the unclarity and confusion. Instead of intuitive explanations (like pilot waves), it is more fashionable to philosophize and give postmodern interpretations (like superpositions and parallel worlds) of physical discoveries, leaving people more confused about the world after learning than before

[@dpt4458]

@@MrFram Talk to any scientist in the field and they will roll their eyes at String Theory and Many Worlds Interpretation. Pretty much all textbook have Coppenhagen. This is a result of pop science influencing the public which in turn influences science right back.

[@MrFram]

@@dpt4458 Copenhagen interpretation is still a postmodern outlook that encourages broken mental models

[@dpt4458]

@@MrFram Then please tell me wgat interpretation would be the true one that doesn't encourage any misjudgements by the public

[@chriswest8389]

The founders of Q M were said to be philosophers not like today's date keepers. Mere technitions.

[@MrZelduck]

The ether frame is not exactly undetectable - it's supposed to be the cause of length and time contraction, which provides a means of detection, it's just that we have no other way of confirming its existence. The problem with that is it means we have no way of determining speeds relative to the ether frame, which means no way to determine the absolute distances and time that the ether frame is supposed to represent. Instead, all we can do is pick some arbitrary frame and calculate things relative to that. But in doing so, we're avoiding the use of the Lorentz theory's primary distinguishing characteristic, reducing it to special relativity, and acknowledging that we can't discover, and have no need for, an absolute frame. At that point the ether frame can be eliminated by Occam's Razor. Also, special relativity is strictly more powerful than Lorentz ether theory in that it provides a fully worked-out explanation for length contraction and time dilation from first principles, whereas the Lorentz theory simply postulates an unknown mechanism by which atoms and molecules physically contract in the direction of travel due to interaction with the ether. (And I'm not sure this can be reconciled with observed length and time contraction between arbitrary frames.) WL Craig amusingly tries to spin the latter issue as an advantage: "Indeed, its fecundity in opening the question about physical causes is an important advantage of the neo-Lorentzian interpretation." He's saying that there's a whole area of unexplored science, namely the physical mechanisms by which atoms and molecules contract along their direction of travel through the ether. Someone should let them know at the LHC! ;)

[@esasakkinen8505]

The interval continuum is the new ether that Einstein meant. It's 4-dimensional and takes projections of time + 3d-space for observers.

[@cinemaclips4497]

What if we define an acceleration as a deviation from a geodesic? We can use the geodesic equation in GR to tell if it is on a geodesic. The definition doesn't involve any forces?

[@zemm9003]

That is the definition.

[@MAElbashir]

Thank you for these great content. I just don't see any problem with defining the absolute acceleration as something that can be measured with an accelerometer. Yes it needs to be calibrated and in the twin paradox situation the calibration will be made at initial state when both twins are on earth. This will show that the traveling twin away from earth is the one accelerating.

[@AliceYobby]

It doesn't even actually need to be calibrated. This guy is obsessed with considering acceleration as being relative when it is not, it is absolute, and there are hundreds of different ways to measure that.

[@alschneider5420]

Here is a decent solution to the paradox. Actually it is not a paradox. Begin with A and B on earth. A stays on earth. B travels to Centari. Speed does not matter nor does acceleration. When B gets to Centari, A appears much older. However, to A, B appears much older. Then, B returns to earth. Due to SR, A and B are the same age. The problem with most descriptions of this so called paradox is that these methods do not take into consideration the direction of motion. You do not understand SR so you cannot see this. I do.

[@MrMoose1347]

This paradox arises from the confusion of coordinate time and proper time. Glad to see you understand that. Lots miss it

[@alschneider5420]

@@MrMoose1347 OK. I called it measured time vs.actual time. Measured time is the time of an object relative to some frame of reference. Measured time is the time a clock displays when observer and clock are moving with speed 0. Actual time is the time of an object at any location in space irrespective of velocity or acceleration. These qualities depend on using a photon clock. Please explain coordinate time and proper time. The confusion referred to in this clip is caused by a false assumption of matter. I am curious if you are aware of this false assumption and understand the reality of the situation.

[@MrMoose1347]

@@alschneider5420 that’s another term for the same thing. No reason to make issue of it. I take it you don’t understand what I said. What’s your confusion?

[@alschneider5420]

@@MrMoose1347 Now I get it. Never mind.

[@MrMoose1347]

@@alschneider5420 cool

[@Flight368]

I’m a topology undergrad, got recommended your relativity videos, it’s a shame I wasn’t subscribed till now. Super good quality content, keep it up!

[@raynethecat3027]

My way of thinking about physics is that it is simply an expression of a way of combining mathematical formulae and values together such that we can say that as long as an object, that we define X, has values a, b, and c, relative to another object Y, we can predict the motions of objects X and Y, and hence the most important place to look for when trying to interpret physics equations is allowing the mathematics to speak for itself (the model speaks for itself so to say) and holding that the phenomenal experiences of space and time are entirely illusory, the same way the experience of emotions are illusory in that they cannot be broken down into a purely formal expression. From our experiences and what we extrapolate from them we can at best construct rigorous, abstract models that show that certain experiences consistently occur and the contents of the experience behaves in a specific way consistently, and what we expect to experience if we choose to perform certain actions such as look through a telescope can be predicted. So we expect to see stars in the sky looking through a telescope rather than say, a gargantuan space duck. Thus when we speak about absolute space versus properties of spatial objects being defined only relatively to one another, it seems to me that the ether that we are accelerating against which happens to exist infinitesimally close to any object accelerating would itself be a mathematical construct that is originally constructed out of objects already being placed relative to one another at different distances. Since when we have any number of objects placed relatively to one another at different dimensions or different ways of relating to each other, that is each object is an element of a set or a "variable" which defines the mathematical expression of said objects, hence the external properties of said objects, such as position and velocity, then we can argue that any set containing a number of objects constructs an ether. I would take the ether then to be defined as a mathematical object which contains all possible values that can exist for a given property an object is said to have, such as velocity, and hence it must be infinitesimally close to everything and infinitely spread out. Thus when we have an object accelerating relative to this ether we already have values of speeds defined for said object, the speed of said object on the mathematical object is recorded instantaneously such that we obtain a continuous flow of change of speeds and properties put in relation to speed over time. In physics, any object or particle can be defined as simply a demarcated set in which certain mathematical values hold within other specified sets/functions (said sets/functions being properties) which must be held relative to each other. (since no property has a meaningful manifestation in isolation, all mathematical objects exist only because we are describing a relationship) That'd be my shot at interpreting relativity.

[@kevconn441]

First of all, thank you for another brilliant video, thought provoking as usual. I haven't read the transcript of Einstein's 1921 lecture for some time, but I don't think he was saying that the luminiferous ether, as commonly understood, must exist. There are three little words that a lot of people, yourselves included, tend to leave out of that infamous quote ie "in this sense" (therefore, there exists an ether). All he was saying, imo, was if spacetime has physical properties, if you want to, you can call spacetime itself the ether (my words). I'm a dubious about the section describing the "calibration frame" of an accelerometer. The spring under acceleration, being pushed by the rocket wall, is not in its equilibrium state, as it would be if it was floating freely. Wouldn't that be its only valid calibration frame? Anyway, I'm going to read the Lindner paper now and see what he has to say. Thanks.

[@christopheriman4921]

Think about how spacetime is, since it can supposedly cause things to accelerate with respect to each other then it is concievable that there is no valid calibration frame because it is always in an accelerating frame from all directions and what you are observing is the relative acceleration in any frame.

[@benjamink2398]

@@christopheriman4921 This seems somewhat ridiculous, though, no? If I'm in an accelerated frame, and I calibrate myself a spring scale within that accelerated frame, then sure -- slowing down or speeding up *in that direction* will cause seemingly analogous deformation of that spring such that it might seem that true inertial was actually a sort of relative acceleration. But -- hold on -- if I calibrate that spring scale within the inertial frame, and then just.... flip it around... it will immediately and radically change shape to respond to the acceleration. Acceleration is a vector, and direction is of utmost importance here. I don't see how Dialect missed this, to be honest....

[@kevconn441]

@@christopheriman4921 I'm a bit confused about how spacetime causes acceleration. Free fall in a gravitation field is inertial motion according to GR.

[@kevconn441]

@@benjamink2398 I'm with you there, that whole idea is confusing.

[@christopheriman4921]

@@benjamink2398 My point with my statement is to say that there probably are no actual inertial frames that exist. Sure maybe you can find a space where the net force applied to any object there is near 0 by every concievable thing but how would you know that you are in that near inertial reference frame or that since in the real world things are made up of parts and those parts are the things that are accelerating due to the net force on them that they won't experience something radically different than the whole? Since we can't calculate something like this practically it makes it relatively difficult to say that we can tell with absolute certainty whether something happened because it was accelerating or because the fabric of spacetime itself changed.

[@sandybottom6623]

Consider this: There is an Ether. The Ether is Space Time. The Ether repels mass and that is gravity. The movement of an electron propagates en EM wave as a 'gravitational wave' in the Ether. ie it compresses and expands the Ether. So if the Ether can be compressed and expanded that produces a different view whilst not changing the basic laws such as the speed of light etc. Gravity is not the attraction between masses. It is a repulsive force where the Ether (aka space time) repels mass. There is various evidences for the existence of the Ether. It has an impedance. It bends electromagnetic waves - look at Einstein's gravitational lensing, gravitational wells, even mirages etc. If you are designing for radio transmission your circuitry through to the antenna is designed on the basis of there being a medium - ie on the basis of a classical spring. So treat it as a medium. When an electron moves it excites the Ether medium. The Ether propagates the wave and then, via gravity, moves an electron at the other end. The Ether is between atoms so the spacing of the atoms effects the propagation of EM waves through mass. If you are going to bend light \ EM waves with gravity that would imply that they have mass. If so that mass has to come from somewhere. It has to be created and be depleted at its source. However if you have an Ether that is bent by mass that easily explains the bending of light \ EM waves whilst at the same time explaining gravity. Looking at physics on this basis explains a lot of things in a simple manner. Ether has a lot of properties and characteristics which we are only just starting to discover. If assuming - via physics orthodoxy - you would assume that Michelson Morley made the correct assumptions about the 'ether'. Suppose that their assumptions were incorrect and then ask what their experiment says about the Ether. If the Ether is Space Time then that would bring even more 'interesting' characteristics to play. And it would imply that the Ether does not have the same magnitudes of its characteristics in all directions. If you move an object into water it's inertia will increase. If you move it back into air its inertia will decrease. If you move it into 'free space' its inertia will decrease but will not be zero. If you are submersed in a submarine in water and you create a tunnel in front of you what will happen? - You will be propelled forward. If you do the same in the Ether the same thing will happen. If you are going through empty space - ie no Ether - you will not have inertia in the general frame of reference. You will be moving your local frame of reference with you so everything will be relative to that including gravity and your inertial state. Your movement will be a result of the gradient that you have created in the Ether. Likewise the force of gravity on you.

[@itzakehrenberg3449]

General Relativity (acceleration) as a "solution" to the TWIN PARADOX reintroduces absolute motion, but not consistently. Q: Which of twins will be old and gray? A: The twin which wasn't moving! He wouldn't experience the time dilation. Q: But I thought each twin could consider the other twin to be moving! A: Nope, if the twins were initially together in an initial inertial frame, and then relative motion occurred between them, one of the twins must have accelerated over some period of time (hey! hey!) to bring himself eventually into a different inertial frame from the other twin. General Relativity then applies. Q: I see, so GR reintroduces absolute motion: The object that has, once upon a time (whose time?), accelerated relative to another object is TRULY MOVING relative to the other object. The younger twin is younger precisely because he was truly moving relative to the old & gray one and we can tell this by the fact that he is young and other is old & gray. Isn't that what you are saying? A: Um... Q: And can't the time period over which is the "moving" object is accelerated be made arbitrarily small, in theory? A: I suppose.. in theory... Q: I must point out the Lorentz transformations do not contain any acceleration terms whatsoever, so if, as SR claims, these easy transformations apply once neither twin is accelerating, i.e., once the two twins are in different INERTIAL frames, then it follows that which side of the equation the factor "(1-v^2/c^2)^1/2" appears on depends upon which object is truly moving and that is determined by HISTORY. Doesn't that follow? A: Umm... Q: Of course, Lorentz & Poincare thought the speed "v" in the transformations was the speed of the object relative to the absolute aether & so none of these paradoxes appeared; it was Einstein who decided that "v" was just the relative speed between any two objects in different inertial frames so they should really be called the EINSTEIN TRANSFORMATIONS, but that is history too, and I digress. Anyway, in applying the transformations between different internal frames, it must get pretty complicated to decide where the all the factors go considering history of the objects must be taken into account & the fact that different objects could have all kinds of wild acceleration histories! A: Ummm... Q: Hey, what about a TRIPLETS Paradox? Suppose one triplet stays stationary while the two triplets accelerate away from her for the same time period (relative to her, no doubt) but in opposite directions???? Once all of them are in inertial frames (no longer accelerating), it follows that, having motion in opposite directions, the two TRULY moving triplets must have speeds relative to each other that are even greater than that relative to the stay-at-home triplet (I'd say we should add the two speeds, but that probably wouldn't be Einsteinian)! Can the Einstein transformations handle all these situations without contradictions??? A: I've got to go. Q: Thanks for clearing all this up for me!

[@dialectphilosophy]

😂😂

[@lamcho00]

"Q: I see, so GR reintroduces absolute motion: The object that has, once upon a time (whose time?), accelerated relative to another object is TRULY MOVING relative to the other object. The younger twin is younger precisely because he was truly moving relative to the old & gray one and we can tell this by the fact that he is young and other is old & gray. Isn't that what you are saying?" A: "Whose time?" refers to the time in the initial frame of reference. "TRULY MOVING" it's just moving. The younger twin is younger, because he undergoes acceleration (relative to the younger twin). From the older twin's perspective, the younger undergoing acceleration, causes him to age at a slower rate (his clock ticks less often). Once back for the twin that stayed behind has passed more time and he's old, while the twin who has undergone acceleration is younger. There is nothing absolute about the thought experiment. Q: Oh boy was I dumb asking this? A: Yes you were, but so were we all when misunderstanding a concept. Q: I hope I can learn from this and not waste my and other people's time on the Internet. A: I hope so too.

[@pwinsider007]

@@dialectphilosophy @dialectphilosophy kzbin.info/www/bejne/g5OkaYKYYtWSps0 This person is falsifying special relativity by saying that Einstein ignores optical laws in his train thought experiment.roast him badly.

[@destroya3303]

@itzakehrenberg3449 You summed it up perfectly.

[@TheDummbob]

I feel like linear acceleration really needs to be distiguished from rotation. The reason is this: The "apparent absoluteness" of linear acceleration can in my opinion be completely explained by the fact, that if you want to accelerate an object, you have to push it with a force, and that force will always (except gravitation!) only "grab" some parts of the object: for example if I push someones back, then the force immediatly only "grabs" onto their back, their intestines are not affected in the beginning. the back is then being accalerated towards the intenstines, creating internal tension and forces. these internal tensions and forces are what we feel when we "feel" acceleration. this is made more clear by considering the exception: gravitation: when in free fall, the "gravitational force" "grabs" every element of our body the same way, every single atom is being accelerated by the same amount at the same time, hence the resulting "acceleration" doesn't feel like acceleration at all, but like "free fall"/"floating" this is the essence of the equivalence principle, that it says this kind of linear acceleration will also give us inertial frames: inertial frames can be lineraly accelerated with respect to each other namely by gravity, and the reason it doesn't seem to work with other forces is because they don't act upon every molecule in your body simultaneously, thus creating inner tensions and forces and hence the "feeling" of acceleration. In this sense I feel like GR atleast gave us relativistic acceleration without "ether" if we only consider linear accelerations. However rotation seems to be something else. still I feel like this should be boiled down to the core, and getting rid of linear acceleration via this argument brings us into a postion where we can more precisely ephasize the real "problem"

[@AntiCitizenX]

I'm about three minutes into this video, and the number of technical errors is really starting to get under my skin. 1) Axioms don't exist in science. Axioms are rules we invent in mathematics for defining some deductive system. It's a subtle pedantic nit-pick, but it shows that you haven't actually studied mathematical logic and proof theory. In science, we never declare axioms. We make some provisional statement about casual relationships that is derived from a preponderance of empirical data. These are often called "laws," and they are far from the "unprovable" wild-ass guesses that you make them out to be. 2) Einstein's postulate about the speed of light being constant is not some wild-ass-guess as you portray. That is 100% false. It is a logical consequence of Maxwell's equations, the Lorentz transformation, and the null result of the Michaelson-Morley experiment. 3) There are dozens of papers in which you can logically derive the Lorentz transformation using perfectly mundane assumptions about the nature of space, time, inertia, and relative motion. Again, this is not some wild-ass-guess as you paint it out to be. Once we have the Lorentz transformation, the constancy of c is an immediate result. I feel bad for this video. You certainly put in a lot of work, but it is very evident that you don't actually understand the subject matter, and you're spreading misinformation as a result.

[@WSFeuer]

You clearly haven’t actually studied any scientific subject in depth before, but I’m sure you’ve watched a lot of KZbin videos so you must be an expert. Here’s why none of your criticisms are valid: 1) Every scientific theory requires axioms, as every scientific is a model/hypothesis which requires testing and must resist falsification. 2) Einstein’s speed of light is a postulate. As the video explains, you can replace it with Lorentz’s postulate and still get the same mathematical results. There’s also the one-way light speed issue - Veritasium has a good video on it if you don’t feel like actually studying the subject for yourself 3) Math is not physics. It supplies us with descriptions of our physical world which derive their validity from the hypotheses asserted. The Lorentz transformations follow from the assumed axioms. In this case, they follow both from Einstein’s and Lorentz’s. Only the philosophical narratives about what actually causes these phenomena separates Einstein’s axiom from Lorentz’s. Imagine being such a low life KZbin troll that you have to write on someone’s video that you feel sorry for them for not understanding the subject when in reality it’s going to be people reading your comment feeling sorry for you for being the brainless one.

[@AntiCitizenX]

@@WSFeuer *Every scientific theory requires axioms, as every scientific is a model/hypothesis which requires testing and must resist falsification.* Dude. Watch the video again, and PAY ATTENTION to what is being said. He very clearly says: "Every scientific theory is predicated on certain UNPROVABLE statements." This is absolutely ludicrous. The postulates of relativity are not "unprovable." They have actually been proven quite nicely through countless experiments. So has every other statement of science that has gone through the rigor of experimental testing. The author of this video is completely confused about the meaning of "axiom" and how it relates to science. In mathematics, an axiom is usually described as a "starting point of reasoning," but that's a terribly vague statement. A far better description is that they "define" the rules of formal languages. The Peano axioms are textbook examples of this. So no, axioms are not a thing in science That's a math thing. You use axioms to define a formal deductive system; not empirical theory. *Einstein’s speed of light is a postulate* You didn't even bother reading my comment, did you? Here, just read this and then get back to me when you know what you're talking about: Pelissetto, A., and Testa, M., "Getting the Lorentz transformations without requiring an invariant speed," American Journal of Physics, 83, 338 (2015) 338-340 *There’s also the one-way light speed issue - Veritasium has a good video on it if you don’t feel like actually studying the subject for yourself* A one-way speed of light is absolutely not a thing, my friend. If I seriously have to explain to you why this is a problem, then you do NOT understand physics at all; especially electromagnetism and relativity. Veritatiuam absolutely dropped the ball on that video. It is extremely poorly researched. *Math is not physics* I never said it was, and I have no idea why you felt compelled to say such a pointless thing. *The Lorentz transformations follow from the assumed axioms. In this case, they follow both from Einstein’s and Lorentz’s. Only the philosophical narratives about what actually causes these phenomena separates Einstein’s axiom from Lorentz’s.* I have absolutely no idea what you're even trying to prove or claim, here. It just sounds to me like haven't studied the subject in serious detail. Please go read that paper I gave you and get back to me.

[@Kerr_geek]

I am really interested in this topic, so i searched some articles on this but couldn't find much. Do you have some more articles that explain the problem of "absoluteness" of acceleration? Thank you very much.

[@soopergoof232]

It means acceleration relative to a fixed reference frame (in this case, the space medium).

[@Kerr_geek]

@@soopergoof232 yes, i understand this, but I need papers that describe (matematically) the problem. For example studies that tried to make acceleration relative, or papers where they explain why making acceleration absolute/relative is a problem.

[@NoddyShoulder]

Awesome video and good questions. We are accelerating relative to what? Of course to our own inertial frame, what else it could be, if everything is relative to everything else

[@MrMeltdown]

Current inertial frame. And since this is instantaneously changing it is like a tangent to a surface

[@mosubekore78]

Or it doesn't need to be relative, just take it as postulate that acceleration is absolute. That way we don't need aether and absolute space.

[@reyco1982]

The normal way of measuring relative acceleration is measuring relative distance between objects per time interval. Using a spring accelerometer is measuring a force. On freefall the accelerometer reading is zero yet relative acceleration with ground is visible.

[@carultch]

In general relativity, acceleration means acceleration due only to non-gravitational forces. So you are accelerating right now, against collapsing spacetime due to Earth's gravity, as you are held in place by the normal force, but an object in free fall is considered to not be accelerating (i.e. following the flow of spacetime).

[@tariq3erwa]

Another amazing video! Thank you.

[@bellsTheorem1138]

@Dialect Your video seems to be ignoring that when you accelerate, as in a rocket, you are throwing off mass that carries away some of your inertial energy in that direction. You don't need a distant inertial frame, an ether or an absolute inertial frame to compare it to. The mass you threw off of your ship is perfectly suited for it. In fact, it is exactly when it is thrown when acceleration is felt or measured. You have to constantly throw mass away to continue to experience inertia. Am I missing something?

[@cyrionn]

Once again an incredible work on this video. Can't wait for what's next to come, thanks a lot !

[@Brian.001]

I'm finding this difficult. Would it be accurate to say this: We can /determine empirically/ (by feeling inertial forces) whether we are in an accelerating frame or not. On the other hand, we are unable to explain what makes it an accelerating frame (since there is no available definition of absolute acceleration)? So with Bob and Alice, we can say that Bob is the one undergoing acceleration, not Alice, and therefore is the one to experience time dilation. The problem is that we can't explain why that difference would produce the time dilation. Is that roughly where we are?

[@jonathanhockey9943]

I think that sums it up very well. This lack of an explanation for accelerating frames where at times there is a pretence of having an explanation is where a lot of the errors and misunderstandings are coming. But I don't think the video's suggestions of ether or absolute space would have any hope as an explanation. Physics just settles for defining acceleration relative to inertial frames in a circular manner, then builds up piecemeal spacetimes, and hopes they will fit together under a faith in a kind of underlying Platonic Mathematical symmetry of reality.

[@jonathanhockey9943]

It is perhaps just a limitation in our epistemological access to surrounding reality. A kind of Kantian framework limitation. Personally I think it all indicates quite clearly the unreality of external space. And it is embracing this full unreality of external space that Einstein's partial revolution never completed. The full Machian relational account.

[@jonathanhockey9943]

For emerging ideas in this regard Lee Smolin is a great resource as is Julian Barbour.

[@Brian.001]

@@jonathanhockey9943 thanks very much.

[@wesbaumguardner8829]

The funny thing is, Einstein actually used Lorentz's axioms in special and general relativity, both of which posit length contraction and time dilation and use Lorentz's mathematics. Lorentz published his aether theory in 1904, a year ahead of Einstein's publishing of special relativity. Einstein basically plagiarized Lorentz's mathematics and then did away with the aether and replaced it with Minkowski space-time. This caused all of the paradoxes and problems commonly associated with special/general relativity.

[@kevconn441]

Rubbish.

[@botplays6893]

Not really, Einstein used the lorentz transformations to prove that his work align with that of the already established, nothing more. There are incredibly huge and obvious differences between the two, At least from the eyes of a physicist.

[@wesbaumguardner8829]

@@botplays6893 Why would Einstein need to prove his work aligned with Lorentz's competing theory? Also, why would Einstein even need to posit length contraction and time dilation? Lorentz's theory was an aether theory and he needed length contraction and time dilation to be able to explain the "null" result of the Michelson Morley Experiment and maintain the viability of his aether hypothesis. Einstein did away with the aether in special relativity, so he had no need for length contraction and time dilation. So, what are the "incredibly huge and obvious differences" of which you are speaking?

[@kevconn441]

@@wesbaumguardner8829 First of all, if you read Einstein's paper you will see that he derived the Lorentz equations himself from his starting postulates. So this notion that he "plagiarised" them is ridiculous. Secondly, if you read Einstein's paper you will see that time dilation and length contraction were needed to fix a problem with Maxwell's equations, not the MMX. (hint: the clue is in the title of the paper). The same problem Lorentz et al were trying to fix. If you want to make a serious criticism of a theory or a scientist, you should get your facts right first. Otherwise you just end up making a fool of yourself.

[@wesbaumguardner8829]

@@kevconn441 "First of all, if you read Einstein's paper you will see that he derived the Lorentz equations himself from his starting postulates." It is amazing how that happens when Einstein's starting postulates are the same as Lorentz's, excluding the aether, which Einstein simply reified into Minkowski spacetime. That is, instead of calling it an aether, he made a physical space and a physical time, each with the property of physical geometry that can change and effect matter. In doing so, he literally imbued space itself with at least some of the properties that the aether was posited to have. And, he did this only a year after the publication of Lorentz's paper. Am I expected to believe that he had not read Lorentz's paper at all? No, no no. "Secondly, if you read Einstein's paper you will see that time dilation and length contraction were needed to fix a problem with Maxwell's equations, not the MMX." So basically what you are telling me is that even though Lorentz postulated length contraction and time dilation to explain the "null" result of the Michelson & Morley experiment, he was actually inadvertently solving a problem with Maxwell's equations of which he was not even aware, and when Einstein used the same equations, he was simply doing so to resolve the problems with Maxwell's equations of which Lorentz was not even aware? You know, I do find it strange how Einstein can be claiming to do away with the aether when his theory is entirely dependent upon Maxwell's equations, which are all equations describing various aether interactions because James Clerk Maxwell's electromagnetic theory is an aether theory. Technically, Einstein should have not used those equations at all since they were describing aether phenomena and he was claiming the aether did not exist or is at the very least unnecessary. By using those equations, he was actually sneaking the aether into his theory through the back door. "If you want to make a serious criticism of a theory or a scientist, you should get your facts right first. Otherwise you just end up making a fool of yourself." The following is from the historical introduction found here: www.rarebooksocietyofindia.org/book_archive/196174216674_10151069422921675.pdf "The above theory of Relativity absorbed practically the whole of the electromagnetic theory based on the Maxwell-Lorentz system of field equations. It combined all the advantages of classic Maxwellian theory together with an electronic hypothesis. The Lorentz assumption of polarisation doublets had furnished a satisfactory explanation of the Fresnelian convection of ether, but in the new theory this is deduced merely as a consequence of the altered concept of relative velocity. In addition, the theory of Relativity accepted the results of Michelson and Morley's experiments as a definite principle, namely, the principle of the constancy of the velocity of light, so that there was nothing left for explanation in the Michelson-Morley experiment. But even more than all this, it established a single general principle which served to connect together in a simple coherent and fruitful manner the known facts of Physics." Pages xiv-xv. This is literally in the preface of the book on Einstein's Relativity that is property of MIT. Perhaps you should get your facts straight.

[@photon434]

Ether it's there or it's not. Please accelerate the release of your next amazing video!

[@johnnyboy-f6v]

Hey Mr Dialect, great video as always. I can't say I fully understand all your vids (esp the one about the sky is accelerating up) but I was wondering how the other YT content providers ie Sabine, Nick, Eugene, PBS Spacetime etc have reacted after you called them out for being wrong.

[@benjamink2398]

@@renedekker9806 It was correct, though. Dialect was correct in both criticisms. Time dilation doesn't cause "falling" any more than the sound of waves crashing on the beach enables surfers to surf -- the waves themselves cause both (spacetime curvature causes both the maintenance of earth's constant radius even while its surface accelerates outwards **and** very tiny time dilations). Further, the length of a spacetime path is indeed fundamentally the only proper way to compare two observers like in a twin paradox. Both critiques were correct.

[@benjamink2398]

@@renedekker9806 Maybe in principle, but it's so easy to misconstrue and misinterpret the former that it's no wonder the YTers sound almost like they're contradicting themselves or each other many times. Much better to compare two things that can actually be directly compared, no crazy frame-switching necessary. And yes, his misunderstanding of acceleration is baffling, given the rigor of his other, closely-related thoughts.

[@jscotlandr]

BTW, tensors are just a mathematical tool used to describe a physical system. Scalar , Vector and tensor are essentially the same thing with each including additional dimensions (1, magnitude, for scalar, 2 for vector (direction and magnitude) and 3+ for tensors). They in particular are not a "part" of general relativity, simply a tool used in calculations. Saying you can do the mathematics necessary in relativity without using them is like saying you can add with a computer, a calculator, an abacus or a slide rule - the tool is not part of the answer.

[@BloobleBonker]

Very thought provoking. I feel that lateral thinking is needed. A completely new model.

[@dialectphilosophy]

Stay tuned!

[@stuartdparnell]

Hard to do so when physicists simply refuse to budge in the face of relative absolutism and dark matter, instead creating ad hoc solutions to clean up the mess.

[@maalikserebryakov]

@@stuartdparnelldark matter is not that ad hoc If you apply General relativity on some galaxies , it works perfectly. Proving Gr is valid at galactic scales. But on most of our galaxies it always *underestimates* the orbital speeds of outer orbiting Bodies. Never overestimates. It can be correct, but whenever its wrong its wrong in way thatsuggests there is mass/energy that was not taken into account.

[@destroya3303]

@@stuartdparnell Then we don't rely on those physicists. Might be better to open source it.

[@destroya3303]

@@maalikserebryakov Sir, adding something unknown to the universe to make your theory work is ad hoc by any stretch. Especially something as magical and all pervasive as dark matter.

[@every1665]

If the accelerometer (as mentioned around 7:00) was rotated about X-Y-Z axis's and an average taken, would that null out any base point acceleration?

[@harryr.6744]

The relativity theory doesn't add up because the two postulates it is based on are false. This is really a pretty simple conclusion. The reason special relativity mathematics produces paradoxes and other strange results is because Einstein's two postulates are wrong. Experiments can not be used to escape this conclusion, because if the mathematics is based upon incorrect postulates, the theory is false. Experiments can not correct that fatal flaw.

[@TheoWerewolf]

Hold on - the spring in the rocketship @7:22 - if the rocketship is not accelerating (and there's the actual issue) the spring would not be compressed. Yes, it would stretch or compress if there were a change in velocity (which is acceleration), but at constant velocity. Worse, it would compress or expand by a constant amount if the acceleration was constant, giving the illusion of not compressing or expanding. So the real issue isn't "calibration" but rather never being able to determine the difference between a "truly" inertial frame of reference or one that's constantly accelerating (assuming no external reference points). But there's a way to test this... rotate the spring at a constant angular velocity. If it changes length as it rotates, you're in an accelerating frame. Also, isn't space-time just a way to say "ether"?

[@MATT-ll2zf]

Why don't you respond to criticisms made by CS Unnikrishnan on Special Relativity

[@lowersaxon]

Is this an Indian scientist? I guess so. Any sources at hand?

[@rer9287]

why dont you provide a reference for the exact criticism?

[@usermlgbzzcnm]

is there a link?

[@MATT-ll2zf]

​@@lowersaxonyes he is Indian Physicist and Emiretus Professor at TIFR and also was a visiting Professor at Kastler Brossel alongside with C.Cohen Tannoudji [1998 Nobel laureate in Physics].

[@lowersaxon]

@@MATT-ll2zf Thanks a lot!

[@quintalfer]

Enthralling. Looking forward to your next video.

[@dialectphilosophy]

Thank you so much for your support! We guarantee you won't be disappointed by what is coming next :-)

[@malcolmterzich]

I've been refering to this "ether" as the entropic field for awhile now because I think there is a lot of overlap in different disciplines' questions that might just be the same answer.

[@stefanlicanin9485]

what is a entropic field? Is this same as Entropic space time theory?

[@realbro173]

What tools you use for such mesmerizing animation, kindly let me know I want to use it for my lectures

[@binbots]

General relativity and quantum mechanics will never be combined until we realize that they take place at different moments in time. Because causality has a speed limit (c) every point in space where you observe it from will be the closest to the present moment. When we look out into the universe, we see the past which is made of particles (GR). When we try to look at smaller and smaller sizes and distances, we are actually looking closer and closer to the present moment (QM). The wave property of particles appears when we start looking into the future of that particle. It is a probability wave because the future is probabilistic. Wave function collapse happens when we bring a particle into the present/past. GR is making measurements in the predictable past. QM is trying to make measurements of the probabilistic future.

[@challox3840]

Without the notion of an observer, QM is time independent. Wave functions will evolve according to Schrodinger's equation in both the positive and negative time directions, and Einstein's Field equations are also equally valid in both the positive and negative time directions. My personal interpretation of observers in QM are that they are a consequence of entanglement in statistical mechanics.

[@fkim1471]

These are excellent videos. A major problem though is the insistence on locality. A more general problem is the lack of a clear model of what exists (an ontological model), and the lack of a sufficient definition of what space is/means. None of this matters if you just want to calculate and use your model to make accurate predictions. But if you are serious about understanding reality, you can’t escape these issues.

[@richsalinas]

Another great video. I've never taken a formal physics course in my life but Dialect makes topics easy to understand. Your visualizations keep getting better and better... keep it up, I'll be anxiously awaiting your next episode.

[@justanotherguy469]

I think that it is important to be able to grasp the fact that nothing moves. We only move relative to a non-inertial frame. What is it that makes a car move? If you look at the tires of a car, you will see that it is the point of contact with the ground that makes the car move. That point that is not moving is called the instantaneous center of zero velocity. So the point that is not moving is what causes the car, which is not moving, to move through different inertial frames of non-acceleration. Perhaps the frames are simply configured and exist in accordance with the construct of quantum mechanics, and the change that is experienced is defined by the fundamental limit of the fabric of "reality". That limit is the Planck length and the Planck time. In other words, "reality" is pixilated. The refresh rate is 10^-43 seconds, and the refresh length is 10^-34 centimeters. Between the pixelization of that rate of time and length of space, there is no existence; however, that is where change takes place, and that change is what we perceive as a movement and an acceleration. Perhaps "reality" is constantly being created from the emanations of virtual particles from the quantum vacuum as the precession of the procession from one instantaneous center of zero velocity to another instantaneous center of zero velocity takes place, and is constantly being destroyed or "pulled back" into the void in the quantum vacuum. Matter can neither be created nor destroyed, but matter can be recreated and re-destroyed. Re-destroyed, as in being drawn back into the void in the quantum vacuum, and I think the same postulate applies to inertial and non-inertial frames of reference. What we perceive as acceleration is merely the recreation of spacetime and matter itself but in a different position. The Universe is constantly being recreated and re-destroyed every 10^-43 seconds at the ultimate inertial frame of reference of 10^-34 centimeters. Newton and Einstein are both correct. It is the inadequacy within their description of what is actually taking place that leads to the conflict between the two.

[@fizykaliceum8454]

For years I have been looking for theory in which gravity was explained by movement of space so no wonder I like this channel. This concept raises questions about absolute space. Why does this space not slow down bodies moving in a uniform rectilinear motion. The existence of a maximum permissible speed in this concept seemed obvious, and it seemed to me that its limited value could be the result of the way it was measured. All the ways of explaining the twin paradox that can be found on major physics channels seemed unconvincing and illogical to me. Even if you're wrong, your videos are very inspiring and I'm surprised by the low number of subscribers. I am even more surprised that there is no discussion with you on these most famous channels about physics, which greatly reduces their value because surely the creators of these channels have watched your videos. This seems to be a conscious attempt to conceal the problem.

[@wesbaumguardner8829]

There is no such occurrence as a uniform rectilinear motion in this universe. All motions are curvilinear. They may appear rectilinear to us from our perspective because we use the earth as a reference frame while ignoring the fact that the earth is rotating on axis in an elliptical orbit around the sun, which is in an elliptical orbit around the milky way galaxy, which is itself in motion. Once all of those various motions are considered, it must be acknowledge that the motion observed is not rectilinear at all. Your question about why space does not slow objects in motion down is a good one. I do not think space itself has the ability to act on anything. Of course I do not subscribe to Einstein's nonsensical notion of a space endowed with physical geometry which can change. Space is nothing more than empty volume. Only matter and energy change. Space is both inside and outside of all matter and energy. All observable borders and geometries are the properties of matter and energy, not space. If matter or energy expands, there is more space inside the matter or energy and less space outside of it, but there is not more or less total space as space is constant and infinite. With that said, I agree with you about the twin paradox. It is nonsensical and their attempts to make it work are futile, as is the case with special/general relativity in general.

[@madScientist404]

We should consider the fact this falsification could also be wrong as GRT has been proven to be right for more than a century now. You cannot just simply dismiss a theory that for example predicted the existence of gravitational waves which were only detected around a decade ago. It could very well be we still don't fully understand what GRT is telling us. Even Einstein himself misinterpreted his own theory a few times, for example when it predicted the universe must be expanding or when Schwarzschild's solution predicted the existence of black holes. I'm not saying GRT is flawless and will never be replaced by a better one. But it is very accurate in its predictions in accordance with what we measure. So it must have gotten something right 😊

[@justanotherguy469]

You can always tell a substantive channel by its thumbnail. If it is one of the people making obnoxious surprising faces, it lacks substance. I use to like Sabine's channel until she started trying to sell through the usage of silly faces.

[@shaunmodipane1]

Why should the information be transmitted to the accelerated frame? 8:21

[@shaunmodipane1]

What I understand is the critical question is who is determining what is accelerating and what is not if no one is causally connected and that there is a fundamental difference between accelerating and not accelerating. It is not about information going or coming.

[@AdRock]

Who is Dialect?

[@creativesource3514]

I've asked this a few times?

[@NoNameAtAll2]

​@@creativesource3514who are you?

[@creativesource3514]

@@NoNameAtAll2 I'm a doctor for the UK. You?

[@motherisape]

Why it matters?

[@Jack__________]

⁠@@creativesource3514 you sound vaccinated. Go through his videos… he’s obviously someone that studies a lot of physics.

[@robinhooper7702]

Here is head scratcher for me. Or maybe I'm misinterpreting. I'm referring to two points of reference that travel a greater or lesser distance in the same time period relative to each other. Point A is located as close as possible to the center of a second hand of a conventional clock and point B is located on that same second hand but at the outermost point on that same second hand. As you can see that point A and point B will return to their starting point in the same time frame and yet both points are traveling at a different speed and distance in order to do so. So, there is no time dilatation, based on the perspective of each point indicated, since both point A and B are physically connected. Is this a very rudimentary understanding and/or is my interpretation incorrect? So, I would think that two people facing each other, one standing next to the North pole and the other standing on the equator would have the same time lapse and yet one is moving faster and a different distance traveled than the other. And this also shows that the two people are connected by way of the Earth it self. The reason, in my option is that your example realizes time dealation is because they are not physically connected. Meaning that point A and point B are inertial to one another.

[@robinhooper7702]

@lepidoptera9337 Hi, thanks for your response. Can you clarify what is meant as an unbending clock hand. Clock hands don't bend unless they are forced.

[@robinhooper7702]

@@lepidoptera9337Thanks for your reply. So I take it that you did not read to the end where I likened this to standing an observer at the North Pole and the other observer is on the Equator. This is not a rod. And no. "All you have to do is to leave an object alone and it will automatically define a straight line". It will not. It will trace a line influenced by the coriolis effect.

[@robinhooper7702]

@@lepidoptera9337 Ah, yes Einstein's elevator. That my patient friend, clarifies this for me, just a bit more. I was under the impression that each others observer from their local viewpoint was inertial. Thank You. May I ask you one more clarification? It is in regards to The Lorentz force. What I've noticed is that every demonstration that I have sourced, shows a wire being influenced up or down, left or right in more or less a straight line, showing a deflection. I also noticed that the deflected wire is attached/anchored but able to move. I have set up a demonstration whereby the wire, a current carrying conductive rod in my case, is free to be influenced within a magnetic field, but the ends of the rod is free to be influenced, in any direction because it is not attached/anchored in any way. The rod rolls rotating on its axis instead of moving in a x or y direction. What is this principle called? I would be happy to forward the video link to you, to clarify this demo.