The REAL Reason You Don't Understand Relativity

[@lorigulfnoldor2162]

Since you are teaching relativity, saying "those who teach it don't understand it either" is a very bold and humble statement...

[@lukasrafajpps]

I didn't see Sabine's video but from this video, I feel like there is a misunderstanding. The postulates of special relativity just simply cause the fact that certain physical quantities that were well defined in Newtonian physics are no longer well defined. One of such quantity is for example length. Since we don't have absolute simultaneity anymore, it is difficult to define what the length is because if we want to measure length we need to measure the coordinate position of two ends of a certain object simultaneously. Therefore without absolute simultaneity, coordinate length is no longer a good quantity which means it depends on the reference frame you measure it in. Therefore if you want to define a quantity called length, you have to specify better what it means. For this reason, we have "proper" length which is the length of an object in its rest frame. This is the same with coordinate time. Coordinate time is no longer a well defined quantity in special relativity because how can we compare two clocks if we don't have an absolute simultaneity? for this reason, comparing time only make sense when measured at the same position so that the relative simultaneity is negligible and therefore time difference on two clocks have a real physical meaning. When Sabine said acceleration makes time dilatation real I think she meant that it is necessary if we want to compare two clocks at the same position because there is no other way to bring the clocks on one place. Therefore acceleration is the key to make time difference on two clocks a well defined quantity and therefore "real".

[@GreenSkid]

Well done. You address the OP's misunderstanding in a clear and straight-forward way, but OP never responds to such comments, and continues to disparage professional scientists. I feel the OP is somewhat delusional, but their video production is great -- I really wish they would see their misunderstanding and make a truly great video by identifying their own error and correcting that!

[@m.c.4674]

The time difference is physical , because what the clocks are doing , but it is not time that slows down.

[@whiteeye3453]

Exept he did make video about acceleration

[@nolanr1400]

​@@m.c.4674exactly

[@hyawill8944]

Ever heard of clock synchronization? Lack of simultanity? Where? Because of coordinate time being different you claim it is impossible to synchronize? If I can synchronize clocks in one frame and I can synchronize two clocks from different frames, therefore I see no problem in synchronizing two pairs of clocks in two frames of reference. A distant clock in "moving" frame of reference will have different coordinate time but the same value after synchronization and it will tick with the same time dilation rate.

[@TerryBollinger]

14:37 _“You don’t understand [special relativity] because the people teaching … you don’t understand it… [__13:12__] We need to re-examine … in particular, the assumption of absolute acceleration. [__15:17__] So hold on to your socks because our channel is about to move into uncharted territory.”_ Excellent research, but you’ve reached a conclusion that is non-physical since non-gravitational acceleration _always_ requires energy. Energy consumption is an observable - a historical result that, once done, becomes irreversible in both classical and quantum physics. Moreover, it requires energy proportional to the acceleration imparted. Thus, if you look at energy, non-gravitational acceleration is necessarily “absolute” regarding the observable energy consumption. The deeper problem is too much focus, then and now, on the non-physical concept of _unbalanced_ accelerations. Those don’t exist. In experimental physics, you _always_ see good ol’ Newtonian action-reaction pairs in which every action (acceleration) has an equal and opposite reaction (acceleration in the opposite direction). The momentum magnitudes imparted to the two units are identical, though the allocation of _energy_ to the two units can vary enormously due to the difference in the mass ratio of the pair. Now, watch this part closely: Would you agree that the successful insertion of some specific amount of energy into a cohesive lump of matter is an “absolute” event in terms of being historical and irreversible in both classical (e.g., batteries) and quantum (e.g., atomic excitation) physics? Yes? The next question is this: Is the lump of matter _required_ to stay spatially localized for its excitation to remain absolute and historical? Of course not. The battery may remain compact in space, but it may also explode. The atom may stay compact for a while but eventually re-radiates the energy or possibly ionizes. Thus energy insertion is an absolute event _regardless_ of whether the unit stays compact. Notice that disruption includes the case of the unit breaking into precisely _two_ components, moving in opposite directions - that is, action-reaction pairs. The point is that action-reaction events - which is to say, _paired_ accelerations - are energy-consuming events within the non-energized frame that launches them. If one pair member is vastly more massive, such as earth versus a rocket, it’s easy (but also not entirely correct) to _approximate_ the launch as a one-sided acceleration. The earth accelerates slightly in the opposite direction, acquiring the same momentum as the rocket. However, the _energy_ absorbed by the earth in such an asymmetric-masses event can, in most cases, be utterly ignored for calculation purposes. But it remains real for both sides since you cannot impart momentum without inserting some energy. Okay, non-gravitational acceleration as _paired_ events is always absolute and historical. So what? What does all of this mean in terms of time dilation? Just this: From the moment of energy insertion into an action-reaction pair, the launch frame always sees clocks in accelerated pairs as moving slower. Notably, there’s nothing relative about this. The launch frame can measure those clocks anytime it wants to, at any point along their paths. When it does, it _always_ sees a total elapsed time identical to the moving clocks ticking slower. That’s why particle accelerators work! A particle accelerator is an excellent approximation of a launch frame since it acquires almost no momentum energy from launching the particles. The particles, however, absorb enormous amounts of energy per particle compared to their rest masses. As long as they retain that energy relative to the frame that launched them, _their clocks run slower than those of their launch frame._ There is nothing relative about how their clocks slow down since that slowdown is _continuously_ measurable as they travel. All “relativity” of time is lost because the launch frame _never_ acquired the energy needed to slow down its clocks. The point is this: Energy acquisition is an absolute and historical event. When that acquisition takes the form of linear momentum, it _constantly and continuously_ slows down moving clocks relative to launch matter that received no such energy. The correct resolution to time dilation is almost absurdly simple: Follow the energy. A final observation: Yes, the Lorentz equation works, but it’s also a bit of a historical disaster that has impeded a more straightforward understanding of phenomena such as time dilation for over a century. The Lorentz or gamma factor, γ, is a computationally messy average of two more important numbers: the forward light path ratio R and its inverse 1/R [1]. The Ratio is identical to _e_ to the power of the particle physics quantity known as rapidity, but it’s a lot easier to think of it as the ratio (to the rest-frame case) of how much farther light must travel to reach the front end of a moving object. This ratio increases as the velocity of the object velocity increases since the light must travel farther to “catch up” with the front of an object that is moving close to lightspeed. ---------- [1] T. Bollinger, _Formulas and Google Equations for Converting SR Velocity Factors,_ Apabistia Notes 2023-02-08.2230 (2023). sarxiv.org/apa.2023-02-08.2230.pdf (a PDF copy of this 2023-04-29 comment is available at sarxiv dot org slash apa)

[@blue5659]

Yes,lorenz transforms are difficult to use, and their derivations are not direct either. Using rapidity and forward light paths ratio is so much easier. Relativistic doppler effect is easier to express from rapidity even in a general angle case. I think the real reason we find relativity difficult to intuitively process, is that Newtonian Galileian relativity was hammered into us, so the better theories are rejected by the parasitic false theory. Relative/absolute accelerations in a Machian philosophy is not about a closed system in the first place. And we have to accept that we are learning two disjointed theories that don't have a satisfactory easy overarching GUT

[@kneau]

*takes notes*

[@TerryBollinger]

@@blue5659yes, rapidity and relativistic Doppler are nice. I was surprised when after deriving a formula for the forward light ratio R -- my real goal was to get a good number for characterizing the distortion of the the invariant areas of transformed objects under the Minkowski hyperbola -- the equation turned out to be identical to the relativistic Doppler factor. However, the one that baffles me most is why textbooks, at least in my experience, never mention that Lorentz contracted objects _must_ be internally asynchronous with an age gradient α = -βγ/c. I had to invent the phrase "age gradient" just to say that since, after multiple checks, I could not find an existing term for that equation. I figure most folks _know_ moving objects must be internally asynchronous just from Einstein's famous train thought experiment, since if the lightening took place _inside_ of the train instead of outside, by simple observer symmetry, its flash would become asynchronous, appearing as a forward-moving flash moving with tachyonic velocity. (The equations are identical; tachyons are, in fact, a misunderstanding of this very effect.) I know from talking to some good particle physicists that what happens is in almost every case the same unconscious trick folks do at event horizons: frame flipping. Asynchronous physics _bothers_ people in all sorts of ways, despite it necessarily giving the same physics, so folks "jump" to the particle frame and think, "Problem solved!" Except it isn't, not if you have _two_ finite-diameter nuclei or nucleons colliding head-on. The opposing age gradients become _quite_ real in that case, yet I've yet to see an LHC model that mentions that point. It's a very minor correction for such tiny diameters, but it's also real and should be included. Instead, you get Monte Carlo simulations that assume _single_ frame time for the whole QGP. Argh. Sloppy, even if it's a small delta.

[@lindsayweir4931]

nice comment

[@TerryBollinger]

@@lindsayweir4931a quick Google Scholar check says you help kids. So thank _you,_ that's way more important work than physics stuff!

[@b.munster2830]

In my experience, the best way to understand the twin paradox (and the rocket paradox) is as follows. A clock measures time, like an odometer measures distance. This allows us to translate the twin paradox in spacetime to a similar paradox in 2D space, which can be understood more intuitively. Imagine two straight roads crossing each other at an angle of less than 90 degrees. Two cars start from the crossing and drive the same distance along each road (on their own twin odometer, or up to the first milestone along the road, assuming those milestones are at equal distance from the crossing). There they stop and observe where the other car is, relative to a line perpendicular to one’s own road. Both will find that the other car is behind and needs to travel further to reach that perpendicular line. This is the same principle as the twin paradox. Next, let’s call the cars Alice and Bob, and imagine there is a third straight road, which crosses Bob’s road where he is and Alice’s road somewhere ahead. Bob makes the turn to get back to Alice’s road. Immediately after turning into the third road, he observes Alice’s location again, relative to a line perpendicular to the third road. From Bob’s new perspective, Alice seems to have “jumped ahead”, simply by turning, even though Alice has not moved at all, and from her perspective Bob has hardly moved while turning. Finally, both continue their journey up to the point where the third road crosses Alice’s road, where Alice and Bob meet again and compare their odometers. Surely both will agree that Bob travelled a longer distance than Alice. It does not make sense for Bob to say that he travelled in a straight line all along and that it was Alice who turned back to him (even though her relative direction did change from Bob’s perspective while he turned), as that is simply not true and would lead to an incorrect theoretical calculation of odometer readings, which does not agree with the actual odometer readings. Only if both agree that Bob turned and Alice did not, they will calculate the correct readings that agree with the actual readings. This is a perfect 2D analogy of the twin paradox. The travelled distance translates to proper elapsed time, the odometer readings to clock readings. Bob’s change of direction by turning translates to change of velocity by acceleration. The math is not exactly the same, but very similar.

[@aaxxsed]

What is the interpretation of odometer in the analogy to proper time? Bob's odometer will show longer distance travelled than Alice's. If this corresponds to longer proper time, then it is opposite result of twin paradox.

[@b.munster2830]

@@aaxxsed Proper time translates to proper distance in the analogy. The odometer measures proper distance like a clock measures proper time. Bob’s odometer measures Bob’s proper distance. This is indeed longer than Alice’s. Like I said, it is an analogy which gives a similar paradox, not exactly the same. The difference in the math is that Alice can calculate Bob’s proper distance by using Pythagoras rule d squared = x squared + y squared, while for Bob’s proper time tb squared = ta squared - (y/c) squared, where ta is Alice’s proper time and y is Bob’s distance from Alice, in her frame of reference. And c is the speed of light.

[@sobeeaton5693]

Acceleration does not register on your odometer, so it is not a good analogy for a clock.

[@b.munster2830]

@@sobeeaton5693 A clock measures time, not acceleration either. In this analogy, travelled time is replaced by travelled distance and that is what an odometer measures.

[@sobeeaton5693]

@@b.munster2830 Since there is an infinite number of curves between any two points it will be necessary to calibrate your curve so that it behaves the way you want. That calibration will necessarily require an accelerometer. While a clock is not a particularly good accelerometer, it is sensitive to acceleration.

[@angeldude101]

Probably the most radical interpretation that I've seen of General Relativity is a 5D one. This one caught my eye largely because of your great videos on the metric tensor. In it, you described how it's like trying to translate from the distances and angles on a map into the distances and angles on the physical curved globe. The only problem with this is that the metric tensor in that context is nothing more than an artifact of trying to represent the surface of a 3D object on a flat 2D plane. What's more intuitive: angles and distances changing mysteriously as you move around, or angles and distances changing because the surface is physically being extruded into another dimension? Distances on a map changing would be very confusing... up until you realize that it's just because there's a mountain at that point with large changes in altitude. Returning to general relativity, the analogous operation would be to introduce a 5th dimension, likely having some relation to mass, energy, or gravity, and then have the coordinates in this dimension change so that the overall length of the vectors being used stays constant regardless of what reference frame you measure them with. You are correct in that we need more people accepting that general relativity, like quantum mechanics, has multiple interpretations, and that pretending that there's only one is confusing when everyone presents their interpretations as _the_ interpretation.

[@christopheriman4921]

I had thought up a potential 6D interpretation although it is based off of an asymmetry I see in the dimensions of space with those of time. I think that there could be 1 dimension of time per dimension of space and that would make sense in the context that space and time are actually one and the same thing. I don't know what the implications of such a thing are and don't know how to even go about exploring it but it is something interesting I thought about.

[@dialectphilosophy]

Yup, that exact reasoning was what propelled the Kaluza-Klein theory of unification. We haven't studied it too much, but we do know that it helped lead to the development of string theory (the extra dimensions of string theory of course got made to be 'small' instead of being the background into which our reality was imbedded)

[@daniel4647]

There is a guy named Anthony Garrett Lisi that has a theory where he shows that an 8 dimensional hypercube corresponds to many thing from quantum mechanics and general relativity. It's called E8 Lie groups I think. It's called "An Exceptionally Simple Theory of Everything", the paper. I don't really know much about physics so I don't know how accurate any of it is, but he is an actual theoretical physicist, PhD from the University of California. He's gotten a lot of criticism for it, but so has any scientist proposing something outside the established narrative, so I don't know who to believe since I have no way of checking any of this myself. But as far as I understand it it's a theory that suggests that reality is only partially "visible" to us because much of it exists in higher spatial dimensions. But he also rejects string theory which also operating under the assumption that there are more spatial dimensions. So while I've watched some videos by Quantum Gravity Research, I can't really make out exactly what their, or his, theory is, and I definitely can't tell if it's at all useful like general relativity is.

[@StrawEgg]

When Sabine says that Time Dilation really occurs in the absolute acceleration (and not the kinematical, velocity-based scenario) you go on to point out that observers accelerating (A) and not accelerating (B) won't be able to agree on the time dilation, so they both have the same measure of "realness"... but the point is that this very disagreement only occurs because of the one that accelerates in the first place (A), whereas the one which we assume doesn't accelerate (B) becomes our chosen base coordinate system. Time dilation is certainly more on the side of acceleration (A), because otherwise, if we attribute the same value to both twins' perspectives (the the other, accelerating in relation to us, will be younger) the twin paradox would be an actual paradox: instead, as per the minutephysics video you linked, there is a certain asymmetry, so that the difference in time elapsed only occurs because of the one that performed the journey, and we can be certain that the one who went on the trip and is younger is the one that actually suffered the time dilation. Kinematical and accelerative together describe the elapsed proper time, sure, but elapsed proper time is not at all the same as time dilation. Overall, it seems more like a nitpick than anything else, so I don't think the hostility is really warranted - just by attempting to clarify actual science, all of these channels are already doing much better than those that subvert science not out of ignorance but outright malice, like flat earthers, quantum mystics, crystal scammers, and so on.

[@jm7606]

You can't imagine how happy i am about your comment. I thought of writing the exact same thing. It's kind of frustrating to see people diskredit experts like Sabine. Sure one has to be sceptical and question why things are like they are, but trying to acuse someone with a phd about something you learn in the first two semesters of a physics bachelor is outright disrespectful.

[@VictorCastillo-l2f]

This video is incorrect in so many levels that it is actually funny . One degree shy of flat earthers.

[@BillyViBritannia]

I think the most confusing element in ALL attempts at explaining relativity, including yours, is the notion of an observer observing clocks. We are talking about a theory where observations and their comparisons are critical and yet its never clear whether these observations take into consideration the light travel time between the observer and the observed or whether we are talking about a weird instantaneous observation which assumes some kind of simultaneity in a theory where time is relative.

[@al1383]

Plus you can have another observer who observes the "stationary" clock on earth in motion. Because earth is traveling through the universe. IMO, way too much credence is given to an observation. Observing something does making something so.

[@jeromehattkronen2305]

and 'rigid rods' being introduced to measure distances in the direction of motion. in a theory where such rods Not being rigid at all is the very basis of the theory. Indeed if they (the x-axis) were rigid, the theory would never get off the ground and you'd be stuck with the Galilean transforms. &/or the speed of light would have to be infinity.

[@KpxUrz5745]

I agree that the common requirement for an observer in all sorts of experiments (including thought experiments) creates all sorts of problems and causes questionable conclusions. Quite a few big name scientists and thinkers have concluded that because "observations" and "observer" are so fundamental to analyzing quantum physics, that ultimately "consciousness" is the ultimate factor at work. And then they debate endlessly what consciousness is, and I believe no one has answered this yet. And they appear to go so far as to claim that the observer's observations NOW actually affect what has already happened. Suddenly all this convoluted thinking is creating the need to accept all sorts of bizarre things such as the many-worlds hypothesis, particle behaviors being a product of consciousness, etc. I never liked string theory, and now recently we are hearing that many are saying string theory is suddenly a dead idea. I hope this is true so we can move on. And when we listen to many famous physicists and cosmologists speak on these difficult matters, it seems that each one has his/her own explanations, and all these explanations differ. It is all interesting, but currently not a very satisfying concoction of guesses about reality. For me, the line that most beautifully describes our ongoing misunderstandings about the universe comes from Shakespeare's "Hamlet", where the protagonist says, "There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy".

[@Nowhy]

@@KpxUrz5745 yes string theory and multiverse is a cope out.. who has ever observed the "Universe" or that mythical creature called "Nature"?

[@Nowhy]

@@KpxUrz5745 and yes, it's all guesswork, no facts (the limits of the scientific methods).

[@BobAlexander-t4g]

One random day, when I was in my early 60s, I watched an MIT lecture on KZbin where the prof explained the Lorentz Transformations and it was a “eureka” moment for me. The math made perfect sense. All the implications of Special Relativity made perfect sense. The lesson for me was realizing ( to paraphrase H.L. Mencken ) simple answers to complex problems are always wrong.

[@rbwinn3]

The math does not make perfect sense, and here is why. From either frame of reference, v is the speed of one frame of reference relative to the other. We common people live in something called reality where if one observer has a slower clock than the other, he gets a faster speed for the other frame of reference relative to his frame of reference.

[@Nowhy]

@@rbwinn3 but isn't it more fun to get lost in abstractions and forgetting that one exists and must possibly perish any moment now?

[@Nowhy]

@@rbwinn3 oh, and another why it's not perfect are Gödel's theorems..

[@thharrimw]

​@@rbwinn3ok then explain why this aspect of relativity is a Godel sentence...

[@kevinmcnamee6006]

You didn't actually say anything except that all the other people were wrong. So what's your view?

[@A_GoogIe_User]

Its a fallacy to say that because someone makes a mistake when communicating something that they don't understand the theory. Did you even try to contact her and ask for clarification ? It's also a fallacy to say because of one error (if it is that) all youtube science communicators fon't understand it. You also seem to suggest that none of these people, some of them well versed in the subject, dont know about the alternative interpretations which is unlikely since they are experts after all. You could have made your point by making a video of the correct interpretation. You basically wasted time and effort on something that could have been a few sentences in that video.

[@JoeWithTheHoesBiden]

"the correct interpretation" this is truly one of the biggest misunderstandings in physics of all time

[@Elrog3]

You bring up good points about him assuming that others don't understand, but if they do understand, why they made the videos the way that they did is beyond me. Its certainly more likely that a lot of these people don't actually understand, but some of them probably do (and of them, I bet Sabine would be the one that does). But you are right. This is all conjecture. We aren't in people's heads. He can't make a video about what the correct interpretation is. The important point he was making is that we don't have a correct interpretation and nobody else acknowledges that when they begin to teach their own. It is core to the discipline of science that science is always up for revision. Science will never know truth. It is only a working model. To declare truth is to reject the possibility of revision. Statements like "the speed of light in a vacuum is constant" are presented as true fact rather than a working assumption.

[@bartelsmore6285]

@@Elrog3 Nicely said. Looking forward to reading more comments after the next video :)

[@Nowhy]

Ever heard of the fallacy fallacy? And who got the correct interpretation? Careful about not practicing what you preach or not following your own unsolicited advice...

[@Nowhy]

@@Elrog3 no facts or dogma in the scientific methods, and yet, metaphysics and politics/business everywhere within that special community which doesn't even exist.. Science isn't about truth, yes, except if one would define truth as something that is about speculation and guesswork... Good Input btw! Question is, who will think it through by themselves?

[@zemm9003]

I am confused at the end because there is no such thing as absolute acceleration as a postulate of relativity. GR only has 5 axioms (assuming it is impossible to derive the geodesic movement from the other 4). There is no mention of absolute acceleration and the only thing that could even approach that is the postulate number 4 which is that there is no acceleration in a free falling reference frame which can be easily shown to be equivalent to the geodesic assumption that Einstein used in his original work. Most Physicists including Einstein at first take this postulate at face value because it matches the straight line movement of Newtonian Mechanics and you can obtain it from an intuitive variational principle. Later on Einstein was upset not at "absolute acceleration" or anything of the sort but at the fact that he wanted to remove postulate 4 from the theory and obtain it as a theorem.

[@stewiesaidthat]

Absolute acceleration is the speed of light or c. Nothing can go faster than it, both in space and in time. Since light travels in its own reference frame, independent of the source, it is an absolute reference marker in which to measure all other motion against. Where relativitists get confused is that space and time are two separate frames of reference and that the laws of physics are equally applicable in ALL frames of reference. Newton's F=ma or Force equals acceleration is the fundamental law of the universe. Objects accelerated in space are also accelerated in time. This has been proven numerous times. Why this time-dilation nonsense is still being preached as gospel is unfathomable. The only explanation is that Einstein was placed on a pedestal as an idol without proof of his nonsensical spacetime fantasy universe physics and now nefarious actors like Sabine and Don over at Fermilab are stuck. They can't tell the truth without looking like fools for not understanding basic physics. There is NO basis in reality for relativity because Acceleration is the.force multiplier. Not mass. Properly framed, reality is 180 degrees in opposition to Einstein’s Relativity nonsense. It was proven 400 years ago that gravity is not a force. The most reason was proven during the moon landings. Relativitists have dug themselves a hole so deep, they can't see reality. A universe consisting of TWO frames of reference. Space and Time with acceleration being the frame of reference. Mass is inert, stored energy. It has no force without acceleration. Relativity was built on mistake after mistake after mistake. You don't see the errors because they produce a mirror image of reality. That's why Sabine and her pals don't understand relativity.

[@habouzhaboux9488]

At first, I was with you against other physics content creators about the nature of gravity and how time dilation is not actually causing gravity, but you kept repeating one fundamentally wrong concept which is that acceleration is relative. This is confusion on your behalf. In most of your videos, you either explicitly state that acceleration is relative, or you interpret absolute acceleration incorrectly. A simple example is that at 8:00, you failed to take into account how the inertial satellite sees those clocks on the screen as accelerating thus indeed having time dilation due to their spacial distance separating them. What Sabine was saying (or at least the correct way of seeing things) is that in special relativity, there is no way to communicate our time difference. It is meaningless because we cannot measure it. In general relativity we can measure it, so we interpret it as a real phenomenon and not just an artifact of our coordinates. It seems that you are a strong advocator for mach's view about the relativity of everything. You are assuming acceleration is relative, but you are failing to take into account how our physics change when we do so. You either interpret acceleration as absolute, or you have to include other factors in your equations. Exactly how you can interpret a person in a rocket as either accelerating, or under gravity, or a mix of both. Since you are always getting the latter interpretation wrong, I would recommend that you just stick to the simpler interpretation "acceleration" is absolute. The math of General Relativity is not easy, but it's not ambiguous. You can clearly find an answer and there is no room for debate. You should focus your arguments on the communication and simplification of these subjects and not the math itself.

[@jonathanhockey9943]

I think you are right on pretty much all your points here. However, I think it still does cause an issue to state acceleration is absolute without having a way to account for that acceleration. For what is it accelerating absolutely relative to? For Newton he had his absolute space and later we had ether, but what are we left with now post-relativity? We only get at the acceleration indirectly and via some other assumptions that also cannot be verified for an independent external arena, such as the speed of light being constant. Maybe this is the limitation of our understanding of reality. Yet the way the theory is presented it is not stated in this humble way, it is claimed to be true of an independent external shared reality, when the very notion of such an arena is absurd within the parameters of the theory. Falling back on mathematical beauty, simplicity or symmetry for me I find to be inadequate and unsatisfying and slightly dogmatic in a Platonist way.

[@irrelevant_noob]

14:17 you're kind of missing the point here. She *_DIDN'T_* say "only" acceleration can cause TD, she's using that statement as a secondary premise to reach a conclusion. She had P1 A exists, and then merely added a correct statement that was useful to the syllogism: if A then TD. This doesn't mean A iff TD. You own unspoken comment that _many_ things "produce" TD does in fact mean that the statement as she wrote it was correct: it's just a shortened form of "A, like many other things, causes TD".

[@se7964]

What are you talking about?! She literally states in her video that kinematic time dilation isn’t real or physically meaningful, and that the real time dilation comes ONLY from acceleration. She emphasizes this point multiple times in her video (which is of course bizarre because it’s completely unfactual.)

[@irrelevant_noob]

@@se7964 then maybe use one of those other times when she DID use the "only", but what was shown on screen was not incorrect.

[@philweight3480]

You seem to be (wilfully?) missing an obvious point that Sabine made very clear - she was saying that what people generally mean when talking of 'time dilation' is actually a misunderstanding of the role of co-ordinate time (which is not physically real, just a labelling mechanism), whereas there IS a real world variance in time outcomes (I'll call it 'true time dilation' for the sake of clarity) which is caused by acceleration, which in turn is caused by changes of direction in the travel path (not by changes in speed). So 'true time dilation' IS real - there really WOULD be a difference in the time passed for Alice and Bob if one was on Earth and one travelled to Andromeda and returned, but that is NOT caused by the relationship between proper time and co-ordinate time. That's what she means by 'real' time dilation. She wasn't saying (to quote you) "we're treating time dilation too literally" she was saying we're misunderstanding what real time dilation is, that it exists but isn't connected to the hypothetical concept of co-ordinate time. That's different. She doesn't 'transfer' from 'velocity' to 'acceleration' in her time dilation argument, she transfers from 'co-ordinate time' to 'proper time (on a hyperbolic real world curve)'. And she makes clear that it's the path travelled, and hence the directional changes and thus acceleration, which determine the time dilation outcome - so observers taking different paths, and having different acceleration, will have different outcomes. Obviously the conclusion, as heavily implied by that, is that observers who are not accelerating will not perceive the same time dilation as those who are - yet you state that she is implying the opposite. The issue of agreement on the ticking of clocks seems spurious - I'm not sure I understand your premise anyway, but even so, clocks are measuring devices, not 'proper time' It's the agreement on the 'proper time' that would matter - when Bob gets back to earth from his trip, he will be physically a different age to Alice. That will be true (and measurable) regardless of how they each saw clocks ticking during the journey period. At no point does Sabine say that Kinematical time dilation isn't real, she doesn't mention it, and you have inferred that therefore she discounts it. But given that her stated aim was to show why basing thinking on co-ordinate time is wrong, she essentially just goes as far as she needs to to explain how that should be replaced by proper time and accelerative dilation. Someone 'not mentioning the second ingredient' is not the same as someone stating that there is no second ingredient. I also have to take issue with your statement that the kinematical slowing of Bob's clock "is the cause of his slowed ageing". Clocks measure, they don't cause cells to age (or not age so much). Bob experiences less passage of time, less entropic effect, which means his cells are less degenerated, less far along their lifetime journey - whatever it is that lies at the heart of "what time is", that ageing is not caused by the operating speed of a measuring device. Overall, you seem to be hung up on how clocks define 'true time dilation' when in fact they just measure it, and attributing opinions and positions to Sabine which aren't there. You 'tease' that you have the answer, but don't give it. Another "I know the answer, you don't understand it" without sharing it - the internet is full of those. I'm always wary of any proponent of a new theory that starts from a position of attacking others. Time to put up or shut up?

[@stewiesaidthat]

There you go again. Not understanding the physics of this universe. Einstein created a fantasy universe called Spacetime and defined it by acceleration in order to peddle his Relativity Theories. And the low IQ masses bought into it. You exist in a universe defined by force. How is force defined in physics. F=ma. Bob and Alice age (accelerate) at the same rate because they experience the same amount of force in their respective frames. How much gravity/force does Bob experience? 9.8 m/s2. Alice? 9.8 m/s2 How much force/Energy does Bob Alice's clocks use? Good question because the morons conducting the experiments only cared about acceleration. Newsflash. This universe is defined by Force. Einstein’s is defined by Acceleration. What is acceleration? A change in distance from point A to point B. What happens with an increase in distance? A decrease in applied force? How do you compensate for a decrease in force over distance. You increase the amount of force at the source. Does Einstein do that? Absolutely not. The speed/force of light is constant. According to Newton's Law F=ma, if force is constant, then mass or acceleration must change. To show you how ridiculous Relativity is. Let's plug in Relativity into the equation Force is constant (speed of light) Acceleration (time) is decreasing. The difference must go into an increase in mass. Does that match the observations in this universe? Do you honestly believe that an increase in acceleration (decrease in time from point A to point B) results in an increase in mass when force is constant. What are the observations in this universe? Hot water (acceleration) has more mass than cold water? How about solar sales being accelerated in space. Are they gaining mass as they absorb energy and heat up and radiate energy into space? If i could shine a light on gold bars and increase the mass, I wouldn't be on here teaching you cultists' physics now, would I. Spacetime is a fantasy universe created by Einstein to peddle his relativity theories. His laws of physics don't apply to this universe.

[@jonathanhockey9943]

Mate, you have had to engage in complex semantic nitpicking to save Sabine's point, which is a clear sign you don't have a clear point at all

[@jonathanhockey9943]

And why are you defending Sabine? Surely it is Einstein we are supposed to be talking about here. It's not an issue for Sabine personally anyway, this is an issue for all versions of the theory that are presented. They cannot properly explain some of the time effects, because they are committed to an incoherent picture of the space-time block universe as a real thing in its own right. This is not contained in special relativity, but it is needed to claim some of the later things, like curvature of that space-time, as how can you have curvature of something that isn't "there" in a stable and static geometric manner? The truth is that general relativity involves models of spacetime that are built up piecemeal based on local geodesic distortions and deviations that are measured indirectly. These local distortions are all we know of, yet the ontological assumption or dogma that has formed around this over the years is that this must be happening in some independent external block universe arena. Noone ever made an effort to make this ontology coherent, and people who tried soon realised it was incoherent. But without this ontology you lose a lot of power to the theory in cosmology for instance. If we are not really dealing with curved geometrical arena, we have to accept they are just idealisations and models, and so the reality of the big bang would not even come up. Our whole new creation myth that has emerged would be under threat.

[@philweight3480]

@@jonathanhockey9943 If you think me saying "clocks measure time, they don't define/create time" is nitpicking, you have a very poor understanding of the issue. It's all very well you rattling on about "ontology" but you have given no explanation of what your point is, not offered any practical evidence why Sabine's points are wrong. I smell BS dressed up as argument. I stand by everything in my first comment - you've offered nothing to undermine it.

[@alphaomega1089]

You are correct. Time is irrelevant: I'm saying that, not you. It is your rate of change. Slow. Fast. Normal to us on Earth. Question is: what would speed up your rate of change? We know it can be slowed down. Not the medical condition! I'm talking when the Master aged the Doctor. What could cause that?

[@orthoplex64]

OK, several serious problems here. Yes Sabine is incorrect in attributing the time dilation purely to acceleration - a common mistake in explaining the twin "paradox". But you introduce a notion of there being different "interpretations" of general relativity, on par with different interpretations of quantum mechanics. This is inappropriate because there is _no_ disagreement or mystery on what the math of general relativity tells us about what's physically happening; QM has the opposite situation, hence its various interpretations. You also place heavy emphasis on Einstein's personal knowledge, beliefs and opinions about GR. It doesn't matter what Einstein thought. I can't find the exact quote but it's as modern physicist Sean Carroll said, something like "I know more about GR than Einstein did, not because I'm smarter than Einstein, but because we've learned so much more about it since then." Worst of all, you leave the viewer with the impression that time dilation, length contraction, and relativity of simultaneity are just "heavy-handed space-and-time-altering pseudo-mysticism of relativity" that could be avoided with different "interpretations". _What?_ These effects are _observed in experiments_ and do not depend upon choice of coordinates as you say they do. 11:40 "If we want to treat time dilation as something real, then since different observers don't perceive the same manner of time dilation as one another, we seemingly have to accept a solipsistic worldview where different observers can construct different narratives of their existence." Different observers having different observations along their different worldlines is simply not a problem; invocation of solipsism is not warranted. This video's title "The REAL Reason You Don't Understand Relativity" is ironically accurate.

[@dimitrispapadimitriou5622]

Yes, I agree with this comment. Indeed, there are no "interpretation issues" about both Special and General Relativity. Special Relativity is perfectly well defined. Nothing controversial about it. GR is also very well understood nowadays, with some interesting open issues that have to do with cosmic censorship/ CTCs/ Non globally hyperbolic spacetimes. But these are more "advanced " topics. For the usual real world applications there is no problem and of course, no interpretation required.

[@richardjenkins2321]

"Sabine is incorrect in attributing the time dilation purely to acceleration - a common mistake in explaining the twin "paradox"." I think this depends on what level you are trying to explain or understand the paradox at, or what you actually think the paradox is. For me, the acceleration resolves the paradox, because it shows us that it's not a symmetrical scenario - one twin accelerates, the other doesn't. It doesn't help us understand why one twin ends up older than the other, but if we are trying to understand that, we are no longer dealing with a paradox, just a normal, everyday situation in special relativity.

[@dimitrispapadimitriou5622]

@@richardjenkins2321 Not really. Here on Earth we are accelerating :1g. You can imagine a space traveller going to A-Centauri with , e.g.the same constant acceleration until half distance, then constantly reducing speed etc. and repeating the same on returning. But the situation for the observer on Earth and the space traveller isn't symmetrical. They are traveling through different paths ( worldlines) in Spacetime. The spacetime interval ( essentially their individual proper time ) is different for each of them. So, no paradox. The issue here has to do with the different notions of "acceleration" that need to be discussed and distinguished in these videos: 3-acceleration, 4-acceleration, proper acceleration. By the way, the distance between Earth and A-Centauri that the Space traveller counts is less than the ( maximal-proper) distance that the Earth people count. That's another , more intuitive way , to state why there is no paradox.

[@theeddorian]

The distinction between formalism and "intrepretation" is clearly made to make the same point the comment makes. or tries to, and, at the same time, to illustrate the weddedness of thought to a preferred understanding or interpretation. Both QM and Relativity have very useful formalisms, employed in many ways. QM tells us what's really happening, but the tale is consistently at odds with what we expect. As concerns relativity, it fails to properly explain "what's really happening" at galactic and intergalactic scales. That failure has lead to concepts like Dark Matter and Dark Energy, the invocation of "substances" and "energy" that are not predicted in either relativity or QM. The problem is that mathematical formalisms are at their base, linguistic constructions, synthetic. They are rule based, non-trivial, and thus subject to Goedel's incompleteness theorems. No formalism can ever be complete, or "true" except within limits imposed by its own foundational assumptions.

[@thinkgood9707]

Ah, but these effects are absolutely _not_ observed! Take time dilation. All we in fact observe is clock-retardation, the slowing of muon decay, and etc. Never _once_ do we see some independent thing, time, "slow down" or "dilate." Instead, we generate a formal expression which signifies a universal quantitative relation. This universal expression simply describes a collection of observed particular instances of relative motion. That's it. The equation is just that--an abstractly universal object of our reflection. It's the physicist who takes this abstract quantitative relation and unjustifiably claims it to be concretely separated from the particular expressions as their underlying cause--"time dilation." This latter move is no more justified than Newton's own postulation of a force of attraction which _grounds_ the particular instances of gravity. The fact of the matter is that this appeal to formal grounding, which is a subtle and easy conceptual error to make, has lead physicists to badly ontologize their math.

[@alanbarnett6993]

You are wrong; absolute acceleration does exist. The starting point of General relativity is the "principle of equivalence", which states that in a small enough volume, an accelerated reference frame is indistinguishable from gravity. This is generalized to the statement that there is a preferred set of reference frames, the "freely falling" reference frames, in which the laws of physics take the same form. Conversely, the laws of physics can look different in reference frames that are not "freely falling"; e.g. reference frames that are accelerating.

[@michaelstockinger4600]

This channel still suffers from two things: 1) promises of explanations "in the following videos", still waiting for some/all 2) looking down on other physic KZbinrs with long experience in research (and also hobby physicists). It's really cringe-worthy Those two facts make it hard for me to continue watching your channel.

[@michaelstockinger4600]

@@davoutzinger you missed the point, but thanks for misrepresenting.

[@Isclachau]

​@@michaelstockinger4600 😂I think you missed his point. Sabine unfortunately has been taken by the far left. Anything she says should come with a warning.

[@valerierit2003]

​​@@Isclachau will u just f off this left and right wing... Both of the sides are of the same coin.. And science favors none

[@Zorro33313]

nope. this actually makes you wanting to continue watching this channel. what makes it hard is butthurt. just get rid of it.

[@Aecor]

Ah yes physic ytbrs

[@drh255]

I would be curious to know what the professional background of this channel's creator is. The limited content of his that I've seen consists entirely of "everyone else is wrong and/or stupid, and only I know this stuff". This is very off-putting. It's fine to be contrarian, but it would be nice to know there's some authority behind it rather than it coming from some rando on the internet.

[@marcomoreno6748]

Yeah. While I don't think its the creators intent- this kind of video and channel just becomes a festering breeding ground for shit like flat earthism, electric universe "hypothosis" (I'm being charitable here), and other rubish non-sense. The fact is these "formalisms" are useful. I'm genuinely interested in hearing these alternative interpretations of GR/ST alluded to in the outro of the video. But of the creator turns out to be a wack job and just reveals that they're going to be put forth untestable, unfalsifiable, "connect-the-dots" style ideas then it will be not only incredibly diasapointing but also alarming.

[@GreenSkid]

They are almost certainly not a professional scientist - all the folks they criticize have a solid understanding of physics, and their videos are for the general public, and not rigorous scientific papers. There is always a few comments in the comment section indicating the OPs misunderstanding upon which they base all these videos on i.e. a misunderstanding of physical acceleration, but they never address it, but instead claim some sort of mystery for which they hope will be revealed to them soon. They are certainly smart enough to handle some of the mathematics, and wax philosophical, but they are not wise enough to understand what professional scientist are meaning in a time limited explanation.

[@testtest-dw4mq]

How about all 3 of you put your own video and animation of what is relativity?

[@drh255]

​@@testtest-dw4mq well, I'm not an expert, and so I'm not qualified to try to teach general relativity to people. The creator of this video is extremely critical of every other science creator out there. We know the credentials of those other creators, but not this guy. You should always be skeptical of the rando online who perpetually tells you how dumb everyone else is.

[@GIGADEV690]

​@@drh255No 👎 Sabine is clown 🤡

[@sumofalln00bs10]

"... and explaining that our confusion about relativity stems from the simple fact that we're treating time dilation too literally" That's not actually what she said, nor what she meant. There's a real and measurable type of time dilation, and the confusion she tackles leads people to think of another type of time dilation that she labels "pseudo time dilation" (the meaningless one). "But as she implies in the beginning it's the idea that any type of time dilation being real that confuses people" What I heard her actually say was "confusing the coordinate time with the proper time is the reason for most misunderstandings for Einstein's theories that I have came across" Then, immediately after that, she goes into why that confusion over coordinate time and proper time leads to a meaningless idea of time dilation (she says "what people often call time dilation") which she then labels "pseudo time dilation" because "it's a meaningless comparison". "Secondly, she neglects to mention that observers who aren't accelerating will not perceive the same manner of time dilation as those who are". Are you lying on purpose? The very section where she mentions the "real time dilation" is the section where she's resolving the twin paradox by showing the asymmetry of someone who experiences the acceleration and someone at constant velocity (0 in this case). That is literally mentioning someone not experiencing the time dilation due to lack of acceleration. There's no way not to hear her mention the thing you're saying she neglects to mention. "So by no means can we claim accelerated time dilation to be more or less real than velocity based time dilation". But the velocity based time dilation is meaningless, due to treating something as real (the coordinate system) when it doesn't have a physical counterpart (unlike proper time). If the velocity time dilation exists only in the abstract after confusing coordinate time and proper time, but acceleration based time dilation has absolute, measurable asymmetries, then of course one is real (supported by evidence, and logically consistent) and the other isn't (we can literally identify the confusion, and resolve problems like the twin paradox by removing the confusion).

[@20Gero09]

I was also wondering about some of those points as I watched Sabine's video not too long ago and thought I remembered some parts differently. Turns out a few (not all) of the accusations in this video are downright false (maybe not lies if it wasn't intentional), which kinda hurts the overall point (which still exists). If you choose to publicly dunk on someone you better make sure to accurately present their arguments (or even steelman them), but never strawman. This makes it seem like the point was dunking on someone else to make yourself look superior, instead of this being an honest example of an overall valid point of criticism. Edit: this + some of the editing and the large emphasis on other creators on this channel can give the impression that the reason for some of those lies in creating friction with larger creators to access more of their viewership, no matter how valid and interesting your arguments/ideas are. This is NOT to say that valid criticism of other creators is bad in any way, but misrepresentation or taking the worst of the possible interpretations of statements or removing context can create an atmosphere that feels more hostile than it needs to in order to get your point across and point out your criticism.

[@sumofalln00bs10]

​@@20Gero09 I presume it was my "Are you lying on purpose?" question. Of course I should never attribute to malice that which is adequately explained by stupidity. But in this case it doesn't seem adequate. I'm quite without an explanation as to how they can miss something so clear. You'd have to at the very least watch her video to make the statement "she neglects to mention", and the fact they pulled a clip from the section where she does mention should indicate they've at least watched the immediate section where she indeed does mention. And it's not like there are a multitude of interpretations if all we're looking for is a simple mention. And yet despite the mention, and despite the clear clipping near to the mention, and despite the lack of ways to reinterpret what she said into something else. they still go on to say "she neglects to mention"... like, how.... "which kinda hurts the overall point (which still exists)" if the point is to do with other youtubers then maybe, I'm not going to pretend to watch all of them and know if they've made any mistakes. But with Sabine, he's done such a piss poor job that I can't imagine there is a point. he seems to constantly confuse the thing she says with other things she says, and then ignores completely some things she says for no discernable reason.

[@sumofalln00bs10]

not to mention that he criticizes Sabines video then praises the minutephysics video, and also references Einsteins "On The Relativity Problem" (I watched and read both) not realizing all 3 agree with each other.

[@20Gero09]

@@sumofalln00bs10 Yeah, I basically didn't want to lean too far out of the window in assuming intentions like malice in this case, since I tend to try and operate under the mindset that one should assume the best possible version of another person's argument/intention etc (or even steelmanning) which I also talked about further up. But maybe you are right, it is kinda weird to miss some of the points if you were directly taking clips from that content and basically choosing what context to give or leave out. Then again - stuff like confirmation bias can influence how you process arguments and even make you hear interpretations that weren't there, overhear information that disagrees with your preconceived notions etc.

[@20Gero09]

@@sumofalln00bs10 And as for the "overall point" - what I meant is indeed the general observation that the discourse on relativity can have similar problems with confusion about interpretations as QM does, which is what Dialect claim to be the point of the video. And I think there is some merit to this observation, but I also think the focus on "dunking" on other creators done in a way that at times seems unnecessarily petty, especially when accusing others of being "disingenuous" while party misquoting them, hurts the argument and can make the discourse needlessly abrasive.

[@Jaggerbush]

Oh what a teaser. I want dialect to offer up something. Debunking works best if you can offer up the correct solution.

[@blue5659]

It is possible to debunk a statement claiming multiple even primes. How can we give a counterexample? On the other hand, prime occurance frequency is claimed to be logarithmic, many examples exist yet still no proof

[@blue5659]

​@@sunshinesucks1355 i dont know what 3 million factorial is but it ain't 3 either😅😂

[@FirstLast-sy3rj]

an alternative hypothesis is not required to falsify an existing hypothesis

[@hamdaniyusuf_dani]

​@@sunshinesucks1355 Where did he say you have to? Is there a better way to debunk something other than showing the correct solution?

[@ProfessorGood-qi7zp]

But, is he wrong? Sometimes silence is a virtue

[@ScienceClicEN]

This is, again, a very interesting point you bring up in this video. The explanation about acceleration causing "true time dilation" is not only problematic, it is also factually wrong. Indeed, it is very well possible for two objects to start from a same point, follow two different trajectories while both are in free fall - not experiencing any acceleration - and then meet again with desynchronized clocks. That's what happens for example if we throw an apple upwards from the space station, such that it falls back to the station after one orbit. My interpretation of relativity would lead me to say that the "true cause" of time dilation is simply that two objects following two different paths through spacetime have no reason to have travelled the same "distance", i.e. the same proper time. But as you explained, it is in fact dependent on my own interpretation (which I think, though, might be one of the most common amongst relativists today), and it relies on the philosophical assumption that spacetime has an absolute geometry, independently from its content. Something Einstein might not have been satisfied with I guess. An interpretation of relativity I really like is the one following from the Hawking-King-McCarthy-Malament theorem : spacetime would only be a set of events causally linked to each other, and its geometry would only be a macroscopical / statistical property that emerges from this structure :)

[@dialectphilosophy]

Rebonjour! You are right, the point about differing free-fall trajectories meeting again is probably the strongest evidence against the factuality of Sabine's interpretation. (It can be difficult for the lay viewer to differentiate between proper and coordinative acceleration sometimes though, so we'll harp on that point another time.) If one had to guess, Sabine's interpretation likely comes from attempting to link two "real" phenomena we observe in the theory -- the phenomenon that two clocks, when rejoined, will show a very real and measurable time difference, and the phenomenon of absolute acceleration, or the statement that accelerometers calibrated in gravitational free-fall will all demonstrate the same proper acceleration. Since in flat spacetime these two phenomena are invariably correlated (that is, we can't compare a proper time de-synchronization of two clocks without at least one clock undergoing a change in inertial motion) it's understandable why this link might have been made, but of course in curved spacetime this link is most definitely broken, and there is no correlation between readings on accelerometers and differences in elapsed time on rejoined proper clocks. But even in flat spacetime, it would seem difficult to explain phenomenon like the muon experiment if we don't interpret kinematical time dilation at some level as being "real". And your statement that the true cause of time dilation is determined by what spacetime path an object follows on the spacetime manifold is of course absolutely correct. The difficulty for us has always been distinguishing how much of this statement is mathematical vs. physical; it all seems so simple when you consider the abstract mathematical view of geodesics/non-geodesics on a higher-dimensional curved manifold, but whenever we try to relate this mathematical view back to a physical one our confusions always begin to multiply. Oh, and we love ideas and theories about space-time being an emergent property of something deeper. Problem is whenever we read literature on such topics our brains immediately flatline. Maybe you could make a video on it sometime soon :-)

[@alcyonae]

The only absolute in this channel is the authoritative projection of the author.

[@punkypinko2965]

Unlike some of the other channels, for example, Sabine? I would love for these channels to start challenging each other and having debates, you know, like science?

[@3zdayz]

The other part is (sorry for the numerous separate comments). Almost every clock we use is based on spin (except the ideal photon clock, and sort of an hour-glass, which in order to work would have to be in centrifuge and you're back to spin). Spin^2 + velocity^2 = C^2. Although this is generally written as S^2=C^2-V^2. And then we go 'why minus?'... well because it's really part of the sum of the other side. If you are going the speed of light you're left with 0 spin; a photon doesn't change orientation while it travels, it's identical in spin when it arrives as when it leaves. Our matter though is based on spin; and if we were going congenitally at the speed of light, we should have problems with our matter even working like matter; but the atoms are all slowed down because spin is limited. It's possible to model this same dilation using the photon clock mounted perpendicular to the velocity - but a photon clock mounted parallel to the velocity has 2 different speeds of covering 1 meter : 1/c+v and 1/c-v. At 0.5c, that's 1/1.5 =0.66. 1/0.5 = 2; and the round trip time is significantly longer than the lateral clock perpendicular to the length; but now we have to also accept length contraction, then that length can be scaled back such that the long round trip takes the same time as the horizontal. There are very reputable sources like Heaviside that first noted contraction of electron clouds. In my own development of the math of relativity (from the ground up, not assuming anything was right, except 1) the speed of light is constant. (The extra part, in any frame. which Einstein includes ends up falling out from the math, and doesn't really have to be postulated); but then the only way that LIGO would work is if there was length contraction to make the two arms the same time-length.... so I finally found what the space-gamma for length contraction and the time-gamma for time contraction (it's not really a dilation, since it's always a slower clock, except at absolute rest). Anyway, recent 3D demos I've done demonstrating this with simple reality that every photon is essentially a fixed location in space; once emitted, it no longer has anything to do with the source it was emitted from; it doesn't inherit any velocity (except in its waveform, which is red shifted behind the velocity and blue shifted in front and various degrees in between around the sides); but otherwise the network of all points that light was emitted from form a stationary background upon which all motion can be found. Oh - BTW - before I did this light speed relativity stuff, I did space curvature; what if it is that space is literally curved (which Einstein said 'don't consider it this way') but if it was, we would still the same gravity lensing around things, if something like a sun shoved the space even 9,000km to get the right arc that Eddington saw when he measured a star around the eclipse, that's not that much space... that's only about 200 femto-meters per atom; and we measure atoms to be around 60-80. But, if they did displace space, then the things we use to measure them are also shoved away, and flow around a thing, meaning we would think it was a lot smaller than it really is. A black hole then isn't infinite curvature or infinite acceleration, it's just a large displacement of space, which contains the stuff that all other atoms contain, but in MUCH greater quantity. (Could CERN produce a black hole? No, but they can slam together matter-size black hole and destroy them, and we're not doing so well at condensing matter out of photons). But that's even older videos; and a different set of simulations. There was no big-bang (not as we imagine it now anyway). Space is overall stretched by matter, and all the stretching from all the matter that light passes by and doesn't interact with (if it did interact then we wouldn't have seen it), that space is stretched longer than it would otherwise be, which over the time the photon passes through this, has to cover more space in the same amount of time, which stretches out the wave; pretty much a fixed amount for the distance it travels. I'd imagine this space stretching is more of a factor in the nearby space, so things that are near by are more red shifted in less distance than very distant things. The universe is flat (except where it's locally curved by matter). I predicted even before JWST launched that when it did get to see things, it would see galaxies very much like our own as far as it could see - was thrilled to be right :) Too bad I'm noone, and you know it's said to be 'one of those things no-one expected', which was right! :)

[@dialectphilosophy]

A lot of ideas in there, thanks for sharing! Some of what you're saying sounds similar to the river model of general relativity.

[@ericephemetherson3964]

@@dialectphilosophy A very good video with fantastic critique. I believe that people have to admit that there is something missing in the intepretation of relativity or I would believe that there are too many variables introduced into this theory. Something must be discarded. Below are some of my thoughts on this subject which I have taken from different threads on the same or related subject of relativity that I had posted on KZbin. The people who have made videos on this subject seem to syringe some of their ideas into existing ones where suddenly one gets confused or the presenters come up with contradictory statements. This subject is definitely one of controversy since it came out in early 1900 hundreds. To me one main point is how two particles can know of its situation without communicating between each other while experiencing relativity at the speed of light (for sake of argument let's assume that two persons can travel at that sepeed). Anyway, very good points in the video and this video actually opens up more of thought provoking issues which a person like Sabine cannot accomplish. Please, omit the time signatures as they refer to other videos on this or similar subject. A few thoughts of mine on this subject in the video. At 0:52 minute Einstein had a new concept of time. So, where is that new concept of time? Einstein did not have any new concept of time because he never stated any definition of time. At 2:20 minute Einstein saw the clock tower. So, what? What did he see? Time? No, he saw movements of some two sticks going round. It might as well have been a dog running from left to right. He saw no time and he saw no time slowing down as he imagined moving close the speed of light away from the tower. Clocks are inanimate devices and do not have anything to do with time. All ones sees in clocks is the movement. At 4:40 video classifies time as ''flowing''. Time does not flow for if it flowed it would have to be moving. If special relativity is true then any frame of reference moving at a certain speed would be somehow creating new and different ''time''. Einstein's blunder was not his cosmological constant but his the greatest blunder was that he never came up with ''definition of time''. The video here states that time flows and it flows in one direction. Time cannot flow because it would have to move. Also, time has no direction. Also, the observation by a detector collapses the wave function of the particle and we know that the particle's spin is up or down. So, the detector is the cause of this knowledge of information about the particle. But who or what is observing the detector which decided to observe the particle and is that information stored in the detector or passed on? As soon as you interject the detector to observe particles it seems like the detector becomes a part of the whole system and the detector decides on the lot of the particle's existence. One thing has bothered me where ''time'' is being used in equations without defining time itself. We cannot associate time with clocks because clocks have nothing to do with time. Clocks are not mechanisms that detect time and so far there no contraption on Earth that detects time as we know it. This relatvity may be just pure hogwash. I have some objections to this whole idea of time-space. So far no one will come across a definition of time. Nobody has constructed the definition of time, therefore we cannot apply ''time'' to physical bodies and using this enigmatic a ''time'' is an erroneous approach to explanation in this video. Clocks do not measure ''time''. I repeat; a clock is not a mechanism to measure time at all. Clocks do not measure anything; there is no contraption in the World that measures ''time'' or feels ''time''. Therefore, by squaring '''time'' or bringing it to any power is meaningless. Space on the other hand has a physical meaning and by marrying space with time we are making a mistake by combining a ''body'' with emptiness. Time, as we know it, is not measurable but rather experienced psychologically. And even by relating time in terms of psychology, time cannot be explained in conveying words of what it is and when somethig was, is or will be. Until we define time the usage of this ''entity' as a dimension is wrong because time may have constituents or have a force by not being a force itself.

[@existensistrubczthentruscatt]

​@@ericephemetherson3964❤

[@tommywong1127]

I think special relativity should be taught using the two postulates and the consequences of those two postulates. The implication of the second postulation is that signals has a finite speed. It’s not instantaneous. Time is a separation of a series of events. An observer is just a system receiving a signal from those events. For example, an electron releasing a photon and another electron receiving that signal. If the recipient is moving relative to that signal, say it’s moving away, the signal will have to take longer to reach the recipient. If a physical processes is the exchange of photons between particles, that delay in signal is time dilation.

[@AnyVideo999]

I've said this before on one your videos, and I'll say it again. Absolute acceleration necessarily falls out of how you choose what a constant rate time coordinate looks like. In relativity, we have one fundamental example and that is the one of the light clock. We can then define acceleration with the amount a light clock would veer from reflecting back into its aligned spot. I understand what you had said in previous videos regarding Newton and Mach's bucket, as well as the spring example from Sabine, but the light clock is a fundamental example. And any other method of keeping track of a time coordinate that agrees with a light clock will therefore necessitate this interpretation of absolute acceleration.

[@siarez]

@dialect please respond to this comment.

[@peterpoli2839]

I think this channel's creator has a hard time accepting he is wrong.

[@m.c.4674]

When you say absolute acceleration do you mean all objects , no matter there motion sees the same acceleration from object x ?

[@damirdze]

There is no absolute time , therefore there is no an absolute acceleration.

[@Arc125]

@@damirdze I don't see how that follows? The light clock on an accelerating rocket would show the acceleration, whereas a light clock on Earth would not show that same acceleration.

[@brainfreasel9428]

It seems to me that you have misunderstood what Sabine is saying. I rechecked her video and what she is saying makes complete sense and is pretty easy to understand.

[@fkeyvan]

Easy to understand but wrong

[@brainfreasel9428]

@@fkeyvan Can you tell where exactly is she wrong with some evidence if you can manage?

[@fkeyvan]

@@brainfreasel9428 didn’t you just see this video you are writing a comment on?

[@brainfreasel9428]

@@fkeyvan Oh yes I should trust some random person on the internet over somebody who has a doctorate in physics.

[@heinrich6294]

@@brainfreasel9428 no. You should not rust anyone because of there degree but their arguments. It is important examine their arguments and not their authority.

[@DrunkenUFOPilot]

Relativity admitting it has a problem... I never really thought about relativity in terms of interpretation, the way quantum theory has a whole interpretation industry attached to it. This will be a fascinating topic to follow!

[@rmn_sxn]

I’m glad that channels like dialect and scienceclic exist. Dialect needs more recognition.

[@rinket7779]

Lol this guy is just the relativity version of a "flat-earther" - a relatively uneducated guy (does he have a phd in physics?) calling established physicists all wrong - and then substituting his own wacky theory that no one else knows about or believes in.

[@madallas_mons]

​@@nadirceliloglu397I genuinely would like to hear your reasoning on why it is wrong

[@HarryHab-w9k]

no he does not, we have enough idiots as it is

[@HarryHab-w9k]

@@madallas_mons you won't hear this reasoning because he has been suppressed, as will be anybody here who actually knows science

[@RobertoCarlos-tn1iq]

sabine is upfront about where she earned her degrees. Dialect . . . well not so much.

[@patricka2816]

Who are you,Mr Dialect. ? If all experts are wrong in any way, why would you be rights than all others ? What is precisely your theory ? And in what aspect does it differ ?

[@RickLambert963]

Time dilation is happening in two ways for satellites, speed, and gravity. The correction calculation for prediction and control are two parts. Calculations Combined: GR predicts that GPS satellites gain 45 microseconds daily due to Gravitational Time Dilation (time passing more slowly in a gravitational field). SR predicts GPS satellites lose 7 microseconds a day due to Kinetic Time Dilation (time passing more slowly in a moving reference frame).

[@rudolfhough6226]

I think of it this way:.......Draw a square 100mm by 100mm, and draw 45* line from bottom left to top right....Mark the top triangle Phi and the bottom triangle Psi..( they slide past each other on the 45* line, either up or down).....In the center draw a horizontal line any length left to right and a vertical line north and south. Slide the two triangles past each other while keeping the horizontal and vertical lines stationary. While sliding the triangles past each other at different speeds, the horizontal line would vary in lengths measured from the center point outwards as they indicate the volumes on the vertical line. The 45* line would indicate the change in respect of time. To me, and if all three movements are taken together in time ,, would explain time dilation as the inertial capacity changes from the macro source to the point source, and vice versa. This can only work if it is calculated using a cubic volume of space filled with aether, Apparently a spatial algebra has to be developed for that to succeed.

[@PokeNebula]

I’m very skeptical of the idea that this one youtube channel has all the answers for an interpretation to relativity that no other place could give me. But you seem to have reasonable critique on the videos you covered.

[@hosh1313]

The most amazing thing about Relativity is that we had a fella looking for some math for light, and the next thing you know he has decided that the Lorentz Transformation doesn't just apply to length but to time as well. The assumption that time passes differently from frame to frame is now not merely talking about light but the entirety of physics because time is involved with virtually all calculations in physics. Had he said it was absurd that time passes differently from frame to frame, and just gone with length contraction, then this would have basically been a description of how light's Aether bent, stretched and contracted and not effected the rest of physics at all. This was/is monumentally significant!

[@annaclarafenyo8185]

Dude, I understand relativity completely, 100%, with no caveats. It's not even that hard. Your claims are basically misinterpretations of Einstein. His 1920 "Ether" is relativistically invariant, and has nothing to do with the lumineferous ether. It's what we now call a "teleparallel ether", and Einstein didn't seriously expect it to be there, it was just a way of rewriting his 1914 "Entwurf" theory in a covariant manner. This required a field filling all space which defined which way is parallel to which other way at distant points. This has nothing to do with the old ether of the 19th century. The time dilation of General Relativity is literal, it's not frame dependent in a stationary gravitational field. The effect doesn't require you to accelerate. Your claim about 'coordinate observer dependent phenomena' is false, even a stationary observer will see the higher-up clock in the accelerating frame tick faster.

[@annaclarafenyo8185]

@@Thomas-gk42 It's a pain in the neck to reply to these people, so don't expect too many others. I do it out of a sense of duty.

[@blackjack3257]

i totally agree, the fact which they seem to confuse is that time dilation causes the "effect of force of gravity on objects to push them towards the massive objects" and time dilation doesn't causes gravity itself but it causes the effect which pulls things to massive objects who happen to bend space.

[@JazzBlues97]

Hope someone reads this comment. I think that the shortest way of expressing the problem of the twin paradox is this: "Time dilation verified experimentally doesnt prove, but disprove, relativity" Extending that sentence: If you send a clock on a plane, rocket, whatever ship; if you try every experiment possible that somehow excludes acceleration to measure time dilation and always find asymmetric measures (one ages faster than the other), then you have disprove special relativity. Cause relativity implies directly the paradox. So to prove relativity you'd have to get a paradoxical measure. Saddly (or no so saddly) reality, up to this date, never showed paradoxical measures (when done sufficiently carefull). The simple measure of time dilation of one frame vs the other is a prove that is something wrong with relativity, and not as is usually said that relativity is real because time dilation was verified. Verifing time dilation is to validate time dilation formalism in the context of and absolute space. In a relative space, every phenomena that vinculates to observers should present a minimum amount of symmetry, only to not break that relativity. Time dilation as presented in the twin paradox is overshooting the assymetry beyond possible in a relative-like space. This line of reasoning of a paradox applies to every theoretical paradox that talks about something physical: T: theorie A: a result B: a result opposite to A E: experimentation of T If T implies that E on one hand results A and on the other hand (also valid in T) results B - AND - If E done experimentally results only A or B but no both, then theres something wrong in T or in the application of T to reality to describe it

[@BongoFerno]

Relativity is not about establishing which observer is "right", but about how to convert one observer viewpoint into another.

[@Mr_Kyle_]

YES, we need more discussion about other interpretations of Relativity, thank you for going there!

[@hosh1313]

Just love the explanation in relativity for Reciprocity - people look smaller to each other at a distance and squares become rectangles when looked at from an angle! LOL So this proves that TD is just fine!

[@QuicksilverSG]

It should be obvious from Einstein's time dilation formula: γ = √(1 - v²/c²) that time dilation is produced not by acceleration, but by velocity. What's not obvious, however, is which frame of reference should be used to measure that velocity? Mathematically, you're calculating the ratio of velocity to the speed of light, but that's not much help, since lightspeed (in vacuum) is the same regardless of your frame of reference. So 1/c² is in practice just a constant scaling factor applied to v² to produce a non-linear time dilation factor (1/γ) that asymptotically approaches infinity as velocity approaches lightspeed. Hence, there is no such thing as "absolute" time dilation, it must always be measured relative to a specific frame of reference, and depends solely on your relative velocity.

[@QuicksilverSG]

To calculate the accummulated time dilation over the course of a round trip of a spaceship to a distant planet and back, you'd need to integrate the time dilation factor producd by the relative velocity (with respect to the origin frame of reference) of the ship over the duration of its flight. This is where acceleration comes into play, but only in determining the ship's instantaneous velocity at any point during its journey. Since time dilation is a non-linear function of relative velocity, you can't simply calculate the ship's average velocity and use it to accurately estimate its total time dilation over the course of the flight. In practice, you'd likely resort to piecewise approximation to calculate the ship's instantaneous relative velocity at numerous points in time, determine the non-linear time dilation factor for each time slice, and sum up the cummulative amount of time dilation experienced in each time slice. I don't see a shortcut around this problem, accumulated time dilation is inevitably a highly non-linear function of relative velocity.

[@mosubekore78]

Time dilation is real regardless the interpretation or phylosophical stuff, GPS clock adjustment is one example of it. Physicists usually just shut up, calculate, and verify it with the experiment. Even the interpretation of electromagnetic wave or Newtonian gravity in classical physics that being thought in highschool has this kind of interpretation problem.

[@frankmccoy2305]

Yes, it may be real but physicists are having a hard time explaining it to smart people. Photon clocks don't work for the obvious reason that they are based on light! Regular clocks on our walls or wrists or digital or molecular clocks would need a different explanation. And our metabolism! Not good explanations given for real clocks or metabolism. People give nonsense and vague explanations for other devices of measurement other than photon clocks.

[@hoon_sol]

Blatantly false. That's exactly what Sabine is pointing out side wrong. Clocks still all measure the exact same time. See e.g. _Clock Time Is Absolute and Universal_ by Xinhang Shen. *_«A critical error is found in the Special Theory of Relativity (STR): mixing up the concepts of the STR abstract time of a reference frame and the displayed time of a physical clock, which leads to use the properties of the abstract time to predict time dilation on physical clocks and all other physical processes. Actually, a clock can never directly measure the abstract time, but can only record the result of a physical process during a period of the abstract time such as the number of cycles of oscillation which is the multiplication of the abstract time and the frequency of oscillation. After Lorentz Transformation, the abstract time of a reference frame expands by a factor gamma, but the frequency of a clock decreases by the same factor gamma, and the resulting multiplication i.e. the displayed time of a moving clock remains unchanged. That is, the displayed time of any physical clock is an invariant of Lorentz Transformation. The Lorentz invariance of the displayed times of clocks can further prove within the framework of STR our earth based standard physical time is absolute, universal and independent of inertial reference frames as confirmed by both the physical fact of the universal synchronization of clocks on the GPS satellites and clocks on the earth, and the theoretical existence of the absolute and universal Galilean time in STR which has proved that time dilation and space contraction are pure illusions of STR. The existence of the absolute and universal time in STR has directly denied that the reference frame dependent abstract time of STR is the physical time, and therefore, STR is wrong and all its predictions can never happen in the physical world.»_*

[@w.o.jackson8432]

@@hoon_sol I don't understand what you are saying. GPS satellites have clocks which tick at different rates. The recording of the "result of a physical process" is not invariant.

[@hoon_sol]

​@@w.o.jackson8432: They do indeed have clocks which tick at different rates, but that has nothing to do with the idiotic drivel that is relativity theory. Go read Jefimenko.

[@Ildarioon]

@@hoon_sol Jefimenko explicitly accounts for relativity. And he did make some mistakes regarding length contractions that people have pointed out.

[@MatthewSuffidy]

I think the problem is more like this. >Mass does effect the scale of matter in that it is smaller where the mass is higher. >Acceleration is caused by an imbalance in the matter caused by the forces relationships in the matter as per the spatial changes. >Acceleration requires matter in which two things in a force relationship exist, like EMR. >Matter slows down because some of its constantly moving parts go further when there is a higher velocity, so the matter slows down, but time in the Universe is totally universal. >The idea things are the same for all observers is true until close to the speed of light is correct coincidentally.

[@quitgoogle2534]

An honest suggestion for the creator of the channel: dial down the criticism of other physicists. You have some fantastic perspectives, explanations, and video talent... and I believe you'll find that a lot of us viewers share the same thoughts on this.

[@traelstechnologytmalsantua3471]

I'm not a physicist but I disagree. I think physicists may have to much authority over the minds of people. It's becoming to much like physicists are telling us how to think rather than helping us to learn. That's why I think criticism of them is good. A good theorist can help us conquer our reality or become subject to its whims.

[@quitgoogle2534]

@traelstechnologytmalsantua3471 SOME criticism is healthy if it leads to constructive debate. Overemphasizing the criticism is counter-productive.

[@marcomoreno6748]

​@@traelstechnologytmalsantua3471what do you mean "physicists are having too much authority over how people think"?

[@traelstechnologytmalsantua3471]

@@marcomoreno6748 When a physicist makes a theory and it's accepted in the scientifc community it'll eventually be taught as fact in schools even to other scientists. So I mean they quite literally control the minds of people. I'm sure we can see the problems with that since theories have flaws and need to be improved almost every 100 years.

[@pusingfismat7099]

​@@traelstechnologytmalsantua3471 What's wrong with presenting current, best theory in textbooks? Even when improvements are needed, current theories must be understood. You seem to 1️⃣ indicate that presenting current theory is useless, while 2️⃣ insinuating that presenting theory means controlling.

[@retiche]

Totally agreed with what you said. Just to complete you, in one of his letters to Reichenbach, Einstein said: “It is wrong to think that geometrization is something essential. It is only a kind of crutch for the finding of numerical laws. Whether one links the geometrical intuitions with a theory is a private matter.”

[@booJay]

Interesting take, will need time to digest it fully. Can you do one sharing your thoughts on eternalism and whether time is "real"? I'll be keeping my eye on this channel.

[@dialectphilosophy]

Thanks for watching, and that's a very deep and philosophical question! We will have to confront the meaning of the "reality" of time in the not so-distant-future -- at least as far as it pertains to formalism-building -- so indeed stay tuned.

[@derndernit8275]

​@@dialectphilosophy define: Time It seems it relates to "a systematic regularity of motion" The Earth's travel around the Sun A metronome clicking in 1/4 A metronome clicking in 4/4 The transition of energy states in cessium atom Light moving from point A to B at speed X and from B to C at speed X So Time is some regular repeating pattern of particular physical objects motion. Any talk of Time dilation or alteration, would then appear to be an alteration to the regularity of the motions of said physical system. If all the sudden earth traveled around the sun in half the time, it would be said the time unit: Year, would have been dilated (altered) Acceleration and increased velocity is, covering more space in less time. You cover x space at velocity 10, so it would take y time to get from A to B, it's expected to take y time to get B to C and C to D. But if you go to velocity 20, the expected y, will be different. The physicality of this, possibly relates to the differences of materials in environments, the differences of energetic ease with which regular mechanic physical pattern systems could flow differently at the bottom of the ocean, at sea level, at mountain level, and in stratosphere, and on other planets gravity.

[@derndernit8275]

@@dialectphilosophy Is it not possible, seemingly likely, that essentially and ultimately time is two facets: (1) First of all it is the idea of change of any kind, there is then the notion of a unit of change, a rate of change. I am naturally prodded to consider, that the truest most fundamental notion of time would be the smallest possible unit of time, and that all other notions of time are just amounts of the smallest unit: Just as 50 and 100 are composed of an amount of 1's (2) the fact of the arrow, the sequence, 3d space, with many events occuring at the same instance, and at different instances; An occurrence of events for similar and different durations. A thing takes up a length of space, and you can spin it for a length of time. Time is events, change. Stuff exists, it's orientations and interactions change; There are words made to describe and characterize stuff. The word Time was made to describe and characterize and compare and catagorize the various changes of stuff. There is a difference between me holding my breath for 5 seconds, and 20. Holding breath = holding breath 5 does not equal 20. The object, the action is not different, there is an idea, a fact, a reality, a dimension, of duration.

[@derndernit8275]

So is it anywhere near right, in wondering if the smallest unit of physical time would be the fastest possible rate of change, and would that not be the time it takes light to move across the shortest possible distance, would be the fastest (temporal) event in the universe? I don't know the conclusion regarding the realness of physical validity of the planck length, if the universes true smallest possible unit of volume is smaller or larger, or ultimately what even the meaning of the smallest length in 3d volume of space existing, means; But is Light moving across that distance, not the fastest possible change in the universe.

[@alansewell7810]

I also think a reinterpretation of Mach's theory of there being an absolute baseline velocity in the Universe against which all velocities are measured is possible, now that we know the Cosmic Microwave Background is a plausible "ground zero" of velocity in the Universe. Objects at rest relative to the CMB do not experience time dilation. Those that are moving relative to it do, according to the Gamma function.

[@dd8630]

I enjoyed this video greatly, but I did get the impression that you placed a lot of emphasis on Einstein's own thoughts on GR, rather than on the corpus of cosmologists who came after him. As you said, Einstein was mired in his own philosophical assumptions (divorcing coordinates from physical significance was something that he lamented didn't come sooner). Sabine's video is probably one of the best, in particular for mentioning proper time, coordinate time, etc - it's so important but you rarely see it in popsci videos! But I agree that her distinction between a 'real' time dilation and a 'pseudo' time dilation is erroneous.

[@se7964]

but it’s interesting that the “corpus” rejects most of Einstein’s later philosophical interpretations of the theory (such that there was an ether) when he was more mature and understood the theory better, yet retains his philosophical outlook from 1905 when he hardly had the full picture.

[@lfelype.azevedo]

Yeah, no... Seems to me that you don't understand General Relativity well enough to understand these videos and has your own interpretation that you are trying to push through your channel. What would not be a problem if you didn't use the approach 'I am the right one and everyone that says otherwise is wrong'. My well regards anyway.

[@georgeburdell517]

I do like the consternation here with competing youtube channels; I watch Sabine too; and many others -- mostly these are interesting things to think about but don't affect the laymen on the day-to-day. However, the argument needs to be out there to topple us know-it-alls off our pedestals. This channel has engaged Sabine rightly and we will see how she responds... she's a pro and doesn't fade from criticism -- at least what I can tell in her comments.... she actually gets in there and debates.... that's hard stuff!

[@HaramGuys]

Special relativity at university is commonly taught without interpretation of spacetime itself, but just as a natural consequence of electrodynamics on a moving frame

[@1dgram]

Sabine is an expert in QM, not relativity. Her channel covers a wide range of scientific topics and she generally does a really good job, but it often isn't perfect.

[@1dgram]

@@nadirceliloglu397 If you agree with everything she says in the "Think Faster Than Light Travel is Possible. Here's Why." video then I want to talk. She should have included another ship traveling at a relativistic rate but not FTL and applied special relativity.

[@1dgram]

@@nadirceliloglu397 I agree with 90% of what she says (perhaps a little bit more). Read again what I wrote 5 months ago: She generally does a really good job. With that 90% figure I think I can say that we both agree that it isn't perfect.

[@1dgram]

@@nadirceliloglu397 True, but his rate of mistakes was much lower than for the rest of us.

[@gabon35]

Fighting with each other is at the core of our species. As human beings, we clash over our beliefs, striving to prove that our truths are absolute, often based on what we perceive as facts. Yet, in reality, there is no definitive truth or falsehood-there is only what is, enveloped in uncertainty. We continually negate the inner essence of existence, driven by a fear of confronting it. If we confronting it, is like to peeling an onion, layer by layer, until nothing remains. What is left as residue is emptiness. You do not die; rather, all your beliefs, concepts, and ideas dissipate because they are based on a flawed tool: contradictory language. When we communicate through language, we inevitably distort the truth, which resides within the being. What I write here is just a glimpse of what could be.

[@yfakolh7154]

The best question verifying understanding of GR I've come up with: what is the difference in clock ticking rates between object free falling in gravitational field compared to distant stationary observer? Assuming their initial relative speed was 0.

[@Music_Creativity_Science]

Yeah, no difference while free falling. BUT, if stopping the falling object further down in the gravitational field (deceleration with mechanical force) the "dammed up" time dilation (while falling) will be "released". As if the object had been stepwise stationary at lower levels in the gravitational field while falling down to the resulting level. There's no way to escape time dilation while free falling, it will be released or dammed up for future releasing, relative to another object. The drastic case is if the falling object crashes on the surface of the gravitational source (planet), then a huge amount of time dilation will be released in a very short time. Some people say "but that can't happen, the crash time is too short for extreme cases, to create the correct mathematical time dilation". That's not a correct reasoning. If for example an asteroid crashes into the earth with 100 times the velocity of a bullet, it will create a deep crater to expand the time, while extreme time dilation can be released in the atoms. Same thing the other way around, if something is blown away from the earth, the acceleration time for the atoms in the object is expanded (while making a crater in the ground) so that the correct amount of time dilation can be created.

[@tommywhite3545]

A very very bold title, to be honest. And we aren't taught relativity from short KZbin videos. I say we, because like you say so yourself as well it's misguided trying to truly and properly understand relativity from youtube videos. Everyone would also only learn the basics. And they garanteed lead to (stubborn) misconceptions.

[@auseryt]

There are some heavy misunderstanding and misrepresentation of what Sabine actually said. Sadly it is too much to explain it here in the comments.

[@auseryt]

@@davoutzinger yes the problem is with many misunderstandings about one statement. The whole video only talked about one statement from Sabine. There is no contradiction when she talks about the pseudo time dilation from verbosity and the one from acceleration. The only contradiction is in this videos misrepresentation of Sabibes video. There more than one misunderstand points about this and each needs more than i wrote here just to satisfy your polemic post.

[@AquarianSoulTimeTraveler]

​​@Dr Gamma D i just want to give you a piece of logical information. 0 dimensional is nothing, you can fit infinite amount of 0D existence into anysize 1 dimensional existence. You can say the same for the next step up that infinite amounts of 1D existence can fit in anysize 2D space and then this pattern can be continued that infinite amounts of 2D existence can fit into ANYSIZE 3D space... we continue this pattern and can logically conclude that infinite amounts of 3D existence can exist in ANYSIZE 4D existence!!! So on and so forth... this is simplistic explanation of reality... figured i would share with you...

[@hughobyrne2588]

13:13 "We need to re-examine one assumption of relativity in particular ('ONE CRITICAL ASSUMPTION'): the assumption of absolute acceleration". No. We really don't, because the assumption of absolute acceleration is not an assumption of general relativity - nor even of special relativity. The assumptions of special relativity include: (1) if you have a frame of reference which is inertial, and a second frame which is moving at constant velocity with respect to the first, then the second frame of reference is also inertial, and (2), the speed of light is constant in all inertial frames of reference. Absolute acceleration is not an assumption, it's a conclusion, it's a consequence - an application of logic to these two assumptions (to be fair, to make the case airtight, there's probably another assumption, I imagine something along the lines of: if a worldline is observed to be continuous in an inertial reference frame, it is continuous in any frame which accelerates smoothly with respect to an inertial frame). It's true that many explanatory texts and videos may make the assumption that the reader/viewer knows that it is a necessary consequence of GR that there is absolute acceleration. Being a necessary consequence is quite different from being a critical assumption.

[@nicholasandrzejkiewicz]

Have you ever considered, Idunno, reading an actual physics book? Nobody learns physics from youtube videos.

[@Elrog3]

That's false.

[@KarlF45]

Im astonished at the conclusions some of you lept to and then attributed to the content creator, but Im horrified at the attribution of intent from others. Are challenging ideas so offensive to you that you need to see them in that light?

[@fshihab]

This video is well put! One question though: why do you think that absolute acceleration may not be true?

[@ethanbottomley-mason8447]

It seems that rather than saying it is not true, they are saying that if you assume it is true, you get a confusing interpretation of gr, but if you do not assume it to be true, then you get a much simpler interpretation. This is not saying that it isn't true, but rather saying we don't know if it is true, and thus we can construct interpretations with or without it and see what we get. In this case, the two interpretations yield the same observations and therefore, unless for some other reason, we needn't decide on the truth of absolute acceleration.

[@fshihab]

@@ethanbottomley-mason8447 is the simpler interpretation presented in the video? Newtonian mechanics says that forces are the same no matter the reference frame as long as it is inertial. As GR has its base in Newtonian mechanics, this carries over to GR too. Sorry for the oversimplification but saying acceleration isn't absolute breaks Newtonian mechanics and in turn, GR. Makes sense, right?

[@scientificallyliterate7462]

​​@@fshihab Yaar mera naam bhi Fahad hai. Or mai relativity per aik nai theory likh raha hon. By the way twin-paradox is a GR problem not an SR problem.

[@jorriffhdhtrsegg]

​@@ethanbottomley-mason8447 what is an alternative to absolute acceleration? That's what i want to know. No aboslute velocity is easy but it would seem that relative changes to velocity are of some absolute form, inherently, as well as their connection to energy and work.

[@lairbox]

I am working on it, my theory is also possible to test. What really happens, for example to multiple clocks have a different clicking, acceleration doesn't cause a time dilation. What really happens is that when you accelerate something the more you accelerate the object the more the object looses energy due to the E=mc2 equation. So the clock that runs slower radiates loosing energy instead running the mechanism. This has been discussed by an Einstein's paper and proves that there's no time dilation at all, all is very simple and newtonian, because after you have measured the "supposed time dilation" if you weight again the clock you'll find that the clock weights less than the other clocks.

[@victorreis8110]

so condescending and for what? You sound so somewhat immature

[@Elrog3]

He was not condescending about Sabine. He was only condescending about science education in general. And for good reason. It sucks.

[@victorreis8110]

@@sunshinesucks1355 link ?

[@Nowhy]

@@Elrog3 big time!

[@NorwegianViking86]

Great video. I have said this for a long time. General relativity isnt a theory, it is many. It comes down to which physicists who are teaching it.

[@leapdaniel8058]

I still disagree with you on whether absolute acceleration is necessary for relativity. But I'm on the edge of my seat and excited to hear more about this interpretation from your channel. I do think that if acceleration were not absolute, it would be more parsimonious in some sense- more consistent with the original motivation of relativity, describing how the laws of physics could apply in any reference frame. I hope you prove me wrong!

[@JuliusBrainz]

13:27 Clearly acceleration is not as absolute as speed of light, but on the scale of absoluteness, it is more absolute than velocity. Different frame velocities do not change local physics while different frame accelerations do. Also, if velocity is measured, no one can really determine who is standing still and who is moving, hence perfectly symmetric ambiguity. However, if acceleration is measured, there is a physical test to determine who is accelerating and who is not, and there is no ambiguity.

[@JohnDoe-su8ew]

This video is 90% chaff and 10% wheat.

[@dionysianapollomarx]

So are 90% of interpretations of the theory of relativity.

[@algorithminc.8850]

I'm really enjoying this channel. The videos on the twin paradox are quite good. Good thinking ... Cheers.

[@amaliaantonopoulou2644]

I can't wait to watch the second part of this video! Thank you!

[@gianlucamolinari6133]

I have a couple of comments. 1) There is not such a thing like "Lorentz's relativity", there is in fact the "Poincaré's relativity". What people call "Lorentz's relativity" should be called theory of correspondent states and has nothing to do with relativity, it is an absolute theory and the transformations introduced by Lorentz are different from those of Poincaré-Einstein and, most importantly, and contrary to the customary view, it is impossible to derive the latter from the former (and viceversa) without break the Lorentz's theory. 2) There is no solution to the twin paradox. The idea that the view of the accelerated twin can be reconciled with the inertial one by the "time gap" generated at the turn back is ludicrous (at best). Introducing a triplet brother/sister traveling at the same constant speed towards the Earth, and crossing the second "traveler" at the point where he/she turns back, will generate, at the arrival on Earth, a nice debate on who should be younger in respect to who...

[@Mr.Not_Sure]

No, the reason of why you get confused watching KZbin videos on relativity, is because hosts are trying to explain it to a "curious layman" without mathematics.

[@gaemr_o5147]

im genuinely more excited for the next entries on your channel than an episode of any show ive ever seen

[@kenhenson1071]

It's fun that KZbin in some limited fields of thought, like this, has become a venue for the democratization of ideas. I don't understand the math well enough to evaluate your presentation or those of Fermilab, or Sabine, or PBS Spacetime et al. But the fact that you're flinging ideas about at a level physicists themselves don't understand and making those concepts accessible to people like me is laudable and wondrous. Thanks! :)

[@contessa.adella]

Yeah…I wondered this also…Time dilation approaching light speed remains in effect without continuous acceleration…a steady velocity is enough! Yet on Earth we get Time dilation effects due to Earth’s mass…or rather the accelerating infall of space. However, not so fast (pun), because near lightspeed IS different to low speed velocity due to the Lorentz transformation. Being nearly at light speed IS an acceleration because your movement is not just through space, but time also. The real difficulty is translating from squiggly math symbols on a board to a visual image (or near analogy) of what is physically going on in 4D. Let us not also forget….whatever complex philosophical science ideas we conjure up…they MUST be in accord with observation.

[@dylanpool2959]

But isn't Sabine's whole point that the time ontology is based on measurable effects. Therefore your example of the constant gravitational field and the two observers would show one aging slower if they were able to measure their internal clocks against each other. So just like in the twin paradox, this shows her time dilation perfectly.

[@dialectphilosophy]

You may need acceleration to be able to compare two clocks that have been separated and rejoined, and yes, once this occurs, one clock will always be slower, but this doesn't mean the acceleration caused the slowing. To get the correct time dilation, you need to add in the kinematical effects just the same as the accelerative ones. Additionally, in curved spacetime, observers can be separated and rejoined with neither ever accelerating (think of two satellites in different orbits) and their clocks will show different times.

[@chrisglosser7318]

@dialect in the satellite case the the satellites are in intertidal frames, but the difference in curvature establishes as hierarchy in the same sense that two people people running around a central point have a hierarchy (although in case of gravity these differ because there are measurable forces in the latter but not in the former)

[@esasakkinen8505]

The reason for the differential aging is a physical interaction, where a part of the body is taken as a new object of observation - i.e. the rocket ship set off with all tanks full, but returned with almost empty tanks. The propellant aged enormously to keep the ship young 😊.

[@dylanpool2959]

@@dialectphilosophy But if you are unable to compare the clocks without acceleration, this means it does not make sense to consider the time dilation. It seems her point is that you require acceleration so it makes sense to say acceleration causes time dilation. She makes no claim that you do not have to include kinematic calculations as well. When you mention the satellites orbiting in curved space, these are definitely accelerating, otherwise they would not stay in orbit. Their velocity is changing so again acceleration is required to explain what she calls the real time dilation.

[@chounoki]

When you talk about acceleration, you must specify which reference frame the acceleration is relative to. Usually when someone says acceleration is absolute, they really mean acceleration relative to that inertial reference frame is absolute. Because by definition, an inertial reference frame is just a frame whose acceleration is zero relative to a flat spacetime. Just imagine that you are inside an accelerating spaceship, and the spaceship itself is in a flat spacetime (no curvature). If you take the accelerating spaceship itself as the reference frame, then you do not have acceleration at all. But if you take the flat spacetime as the reference frame, then you do have absolute acceleration, because the flat spacetime is an inertial reference frame.

[@mathletics6287]

I really appreciate for what you did. Thank you so much. But I have a question, agreed those famous youtubers don't understand it, what is the guarantee we have that you understand it?

[@dexter8705]

You can see if you watch his videos, the 6 videos before showing the proofs, this video just outlines the situation.

[@dialectphilosophy]

That's a fair question! And the answer is we don't understand it either, at least not fully. But we certainly DO understand that we don't understand it fully, whereas the majority of physicists seem to think relativity is consistent and complete and will assure you that they have complete understanding of the subject. (But then go and say things that are completely wrong!) In the future we will be presenting alternative interpretations of special and general relativity. Nothing says you have to accept these interpretations over the standard one. But they may help lead you, us, and the rest of those who are interested to a deeper and fuller understanding.

[@aaronjennings8385]

When people say "time," there's an instant lack of universal agreement. Literally, time is not understood within any axiomatic context. So time is one of at least three things. No one seems to know.

[@WillyKillya]

When I saw the part and sabine's video that said "acceleration is absolute", I immediately thought of this channel! Anyway, it seems to me that the reason for so much confusion is that KZbinrs go too far to dumb down explanations because they believe "us rubes" can't understand anything more complex, But personally, the whole reason I watch (and rewatch) so much physics on KZbin is try to stretch my understanding. I do realize that without a formal physics background and being able to do the math I probably will never fundamentally understand what's behind the curtain, but sometimes I like to think the math is just how we communicate with each other about science...reality knows no math, so maybe anybody can know at least just a little bit about reality (said in Zach Braff Scrubs Episode-ending monologue rap-up voice😅)

[@enterprisesoftwarearchitect]

@Willy Sound, I too wanted to turn to Dialect and ask, is that right??

[@TIMEPHYSICS]

Clock hypothesis - lack of effect of acceleration. (Time dilation can be calculated precisely with velocity and there is no contribution to time dilation by acceleration. Also dont forget the Einsteins time dilation equation has velocity term and no acceleration term) The clock hypothesis states that the extent of acceleration does not influence the value of time dilation. In most of the former experiments mentioned above, the decaying particles were in an inertial frame, i.e. unaccelerated. However, in Bailey et al. (1977) the particles were subject to a transverse acceleration of up to ∼1018 g. Since the result was the same, it was shown that acceleration has no impact on time dilation.[28] In addition, Roos et al. (1980) measured the decay of Sigma baryons, which were subject to a longitudinal acceleration between 0.5 and 5.0 × 1015 g. Again, no deviation from ordinary time dilation was measured.[30]

[@dialectphilosophy]

Thanks for bringing these up. We would have liked to mention these experiments, but of course one can't "get into the frame of reference" of the particles to know how they would experience time -- but certainly, from the inertial observer's perspective, it doesn't matter how much or in what manner these particles accelerate, as only the velocity contributes to their measured time dilation.

[@The-Martian73]

Only God knows how much do I love DIALECT .... the edit, explanation and the voice ... almost perfect ❤ Thank you

[@yashen12345]

i dont get how any other interpretation of general relativity can exist which denies true time dilation. We have literally measured it with atomic clocks.

[@jayorag]

I'm really grateful to you and your videos because you helped me to understand what awful teachers at university weren't able to. But, honestly, these recent videos, that I think ridicule and make fun of other channels (whether they are right or not) are making the love I have always felt for your amazing content fade away a little. It's really ok to debunk misconceptions and I think it can be done in an elegant way

[@TounInTheHole]

They just explained what they thought was wrong with dr. Sabines explanation, i see no ridicule in that. Do not forget that Sabine herself has very sharp and satiric way of criticising others, she will surly survive one critical video.

[@friedrichhayek4862]

That is the religion of Copenagen and goverment intervention.

[@damirdze]

Exactly the opposite to you. I love him for his understanding and a courage to challenge these so called experts of everything.

[@Elrog3]

Sabine would approve of the conversation being had rather than not.

[@hosh1313]

Disagree - I have no problem with this. It sets the stakes high and if he's wrong then all the egg's on his face. Ignorance, stupidity and false statements deserve to be punished, without people turning into mere xxxxwits! :)

[@JuliusBrainz]

6:45 I think she was comparing coordinate time with proper time. No one has to carry the clock that shows the coordinate time, but everyone's clock shows their proper time. So coordinate time dilation is just a mathematical statement, proper time dilation is a physical thing. Coordinate time is a type of coordinate that can be used to causally order events, but values of coordinate time are not necessarily physical. On the other hand, the value of proper time is physical and directly shows what your clock shows.

[@dialectphilosophy]

You're correct, and Sabine was correct to say that conflation of coordinate time and proper time is a big source of confusion in the theory. However, Sabine turns right around and essentially implies that coordinative acceleration time dilation leads to differences in proper time for clocks -- but differences in proper time come from both considerations of velocity and acceleration.

[@JuliusBrainz]

@@dialectphilosophy Obviously proper time is defined through the integral of root of length element, and this formula includes only velocities and the metric. But integrals will differ (in flat space) if history of velocities is different which is due to different accelerations. I think this is what Sabine meant. Acceleration is the more fundamental reason because it is the reason for different velocities and at the same time it escapes the problem of relativity of motion (we can locally tell apart accelerated and nonaccelerated frames but not two nonaccelerated frames) and the usual confusion coming with it. But if you want to simply calculate proper time differences, then of course you need velocites and the metric for each point along the trajectory. In formulaic terms I would state Sabine's statement as follows: to derive the proper time difference as an input you need initial velocities at one point and accelerations together with metric at every point of the curve. Then, although velocities at every point are needed to compute proper time, they are derivable from accelerations and initial velocities, hence not being the original source of the difference (except for initial point).

[@dialectphilosophy]

@@JuliusBrainz We agree with you, except that that "initial point" thing makes all the difference! If you change the initial velocity, you change the length of the spacetime path. Additionally, you can model the spacetime path as having essentially a cusp wherein the acceleration occurred almost all-at-once, in which case the time dilation is entirely due to kinematical effects. Sabine is confusing the agent of asymmetry in the twin paradox (which is regarded generally as acceleration) with the notion of what makes time dilation real. Is the time dilation of a muon hurtling towards earth not-real? We know it experiences proper time differently than we do, but its extended lifespan is most certainly a consequence of kinematic time dilation, and is a very real thing. Confusions like Sabine's occur because the theory only teaches us to talk about time dilation in mathematical terms, so when we try to make sense of it physically, we generally come up short.

[@JuliusBrainz]

@@dialectphilosophy The fact that initial point makes all the difference is too strong statement. In all twin paradoxes it is usually assumed that twins move in different directions. I think most problems ask about the reasons for time difference modulo the difference of initial velocities. Then the source of asymmetry is acceleration, and this is not a kinematical effect. Acceleration actually affects local physics, so it requires a physical origin. It can be a continuous exhaust of a rocket or an instantaneous bomb explosion, but it is not merely a Lorentz transformation. The muon problem should be separated from the twin paradox, because it is one muon, not two. Muon's and lab's velocities are different, so we have to mention kinematics. For twin problem, one could completely eliminate the endpoint kinematical aspect by even assuming that velocities at both endpoints are actually equal. Then the asymmetry is really coming just from acceleration. But then the twin paradox needs a more precise introduction. Are the starting point velocities the same or not. If we say nothing about initial/final velocities then both Sabine's and your conclusions as absolute statements are wrong. If we want to talk about numbers, we have to use mathematical formulas. Maybe distinction between which numbers are physical and which are not could be made better. This is a common problem even in research, so there is space for improvement of general education.

[@Epursimov]

I asked a question in the comments of Sabine's video, because I was not convinced of the need for acceleration. Suppose the universe is an hypersphere, that is, going straight returns you to the starting point, who ages more, Alice or Bob, as both do not accelerate? I received no response. I hope this channel (which I appreciate a lot) will help me answering the question.

[@LinkenCV]

What appears to you as a straight line in a 4D-hypersphere is actually a curve (otherwise you would not have returned to the starting point by moving in only one direction). 3D analogue of movement along the sphere along the meridian (as an example). Angular velocity... Components of angular velocity are changing. And a=dv/dt For a 4D-hypersphere, the fact that we are moving in time means that we are always in a state of acceleration.

[@dialectphilosophy]

That's a well-put question. It's similar to the problem of two twins in different orbits actually; that is, if we take two twins in separate orbits that rejoin at some point, how do we know who is the older one, since neither ever accelerated? Calculating this requires invoking the spacetime metric, which depends upon the distribution of matter in the vicinity. So the answer to your question would be that Alice or Bob's age would probably depend on the distribution of matter within that hypersphere universe.

[@Mysoi123]

I also disagree with the part where Sabine claims that the difference in time dilation across various altitudes depends on the proper acceleration at each point. In reality, proper acceleration is the same everywhere in a uniform gravitational field; however, different altitudes still experience time at varying rates. Additionally, Sabine was incorrect in stating that the cause of gravitational time dilation for a spaceship near a black hole is due to the spaceship accelerating to maintain its radial coordinate relative to the black hole. In fact, an orbiting spaceship can maintain the same radial coordinate without experiencing any proper acceleration, and yet, the metric tensor indicates a difference in the proper time arc length. This is extremely misleading!

[@pwinsider007]

You said that accelaration is not the solution of twin paradox then you didn't make video on the solution of twin paradox.what is the real solution of twin paradox?

[@cougar2013]

Acceleration is the solution. Though both appear to accelerate, only one is feeling a force. Problem solved.

[@JoeWithTheHoesBiden]

he made five videos! "Even more Paradoxical: The Twin Paradox in Curved Spacetime" "Solutions to the Twin Paradox are Wrong!" "Do Inertial Frames Solve The Twin Paradox?" "Einstein, Gravity, and the Twin Paradox (1918)" "Solutions to the Twin Paradox are Still Wrong!"

[@Voidapparate]

They're going to drag this out and squeeze out every view they can get.

[@iridium1118]

​@@cougar2013 no acceleration required if two rockets moving in opposite directions exchange light signals at the turnaround point

[@cougar2013]

@@iridium1118 ok but now we’re not talking about the twin paradox anymore

[@ndotl]

Comment #1501: As opposed to referring us to yet another KZbin video, I think we (or I) would be better served through suggested texts that might provide a good level of basic knowledge in this area. I do agree that "The Laws of Physics" is an abbreviation for "The Laws of Physics As We Known Them". We have a lot to learn, and that process begins by understanding the things we don't actually know. I think the Internet's ability to accelerate our ability to debate will help us achieve the type of quantum leap in understanding that is needed to help us find our place among the stars.

[@tenorenstrom]

This whole channel feels like carefully packed misinformation.

[@WSFeuer]

you mean like it’s award-winning videos on differential geometry that have some of the best explanations of advanced mathematics many have seen in decades? Maybe you need to accept that questioning axioms and orthodoxies is a natural part of science, and not always an existential “misinformation” threat like your favorite tv news channels would have you believe.

[@alexanderkohler6439]

@@WSFeuer What awards did they actually win?

[@speeshers]

Yes! Very well put

[@xlerb_again_to_music7908]

My sense is that the underlying model is wrong. We seemed to have backed into a new version of planets and epicycles (wheels within wheels). And it seemed to go wrong around the time of Michelson-Morley. My physics teacher didn't teach that the MM experiment disproved the aether; rather that it found nothing. Some might say from that that nothing means the aether does not exist. Or.... your trap to catch some _whatever stuff_ was not a good trap. Nowadays, we understand that an aspect of gravity is that space continually falls into the planet (that's what tries to "push" us down to the ground - see any of Professor Michio Kaku's lectures re gravity and the flow of space). Let's suppose that space and aether are linked (same?). My understanding is that the MM experiment took Earth to be like a ship ploughing through water, so measured a suspected sideways flow displacement on a flat, land based interferometer - a table of apparatus, which could be rotated in a flat plane. To no visible result, regardless of orientation, time or season of year (Earth's place in orbit). Let's now take it Kaku is right. Space is falling in down the z axis onto the apparatus, not sideways on some x or y. The whole MM experiment is now seen as carefully analysing the wrong axis. I'd say that that invalidates the work. Which does not prove some form of aether exists, but does suggest a point at which things started to go astray. After all, prior ideas of aether and vortices worked rather well for James Clerk Maxwell. I would want to widen the intellectual search, especially looking for omitted factors. There may be something at spacial foam level which we have not spotted, or suspect exists, which can explain what is going on. Re Einstein and the aether. HA Lorentz's argument c. 1916 convinced Einstein of the validity of some form of aether. The argument (paraphrased) was: "You can stick a physical probe into a region of space and sense physical properties (eg with a gold-leaf electroscope). For that to be possible, space must possess an aspect which is physical." Another hint from Einstein (not sure of date; again paraphrased): "All forces are forms of geometric curvature of space". Chase that and you may get somewhere.

[@KaiHenningsen]

You seem confused by Sabine pointing at two different examples of time dilation, and calling only one of them real. And no, she's not transferring it from velocity to acceleration, but from passing to coming back to meet. The meeting is the important point here. _she neglects to mention that observers who aren't accelerating will not perceive the same manner of time dilation as those who_ Apart from using those exact words, you actually quoted her when she did?! And yes, it's not acceleration per see, it's meeting up again that creates the "real" time dilation. Two objects taking different paths through spacetime from spacetime point A to point B can, obviously, compare the time they spent on the way between the same set of points. That's the real point here. OK, you even quote her saying exactly this?! _saying only accelerative time dilation is real while kinematical time dilation isn't_ ... you seem confused about what she is saying, or rather, what meaning she is trying to convey. Your Einstein quote suggests that you think she's talking about absolute movement?! Where on earth did you get that nonsense from?! I think your problem is that you expect everyone to conform not only to your personal interpretation of relativity but to your personal way of talking about it. Ah, yes. "They do it wrong, but I won't tell you what is the right way ... but keep watching." I think I know enough by now. Good bye.

[@Elrog3]

Even if you are correct that he has misunderstood Sabine about the "acceleration is the real time dilation" thing (which I don't really care about either way), that doesn't take away the fact that all of these GR/SR explanation videos are presenting their philosophy as if it is science and they should be called out on that.

[@hoon_sol]

*_«A critical error is found in the Special Theory of Relativity (STR): mixing up the concepts of the STR abstract time of a reference frame and the displayed time of a physical clock, which leads to use the properties of the abstract time to predict time dilation on physical clocks and all other physical processes. Actually, a clock can never directly measure the abstract time, but can only record the result of a physical process during a period of the abstract time such as the number of cycles of oscillation which is the multiplication of the abstract time and the frequency of oscillation. After Lorentz Transformation, the abstract time of a reference frame expands by a factor gamma, but the frequency of a clock decreases by the same factor gamma, and the resulting multiplication i.e. the displayed time of a moving clock remains unchanged. That is, the displayed time of any physical clock is an invariant of Lorentz Transformation. The Lorentz invariance of the displayed times of clocks can further prove within the framework of STR our earth based standard physical time is absolute, universal and independent of inertial reference frames as confirmed by both the physical fact of the universal synchronization of clocks on the GPS satellites and clocks on the earth, and the theoretical existence of the absolute and universal Galilean time in STR which has proved that time dilation and space contraction are pure illusions of STR. The existence of the absolute and universal time in STR has directly denied that the reference frame dependent abstract time of STR is the physical time, and therefore, STR is wrong and all its predictions can never happen in the physical world.»_*

[@isbestlizard]

Surely by now, given how we've launched probes into space that use gravity assists, and often return back to Earth a few times during them, we've figured out EXACTLY the solution to the twin paradox, calculated how much time dilation you expect zipping away, delta-ving 10 or 20 km/sec, returning and comparing clocks, or looking at the shift in carrier frequency of their uplinks back to us, or something smart like that, and know FOR SURE a solution?

[@dialectphilosophy]

The reality of time dilation is well past confirmed (at least with regards to its effects on atomic clocks). But as we state in this video, that does not mean the philosophy of the theory is correct, i.e., it does not imply that "time itself" is actually slowing down, as there are other interpretations one can give to the phenomenon (such as the Lorentzian ether interpretation).

[@charliejohnston1978]

Massless particles and energy waves are dull-images of the same energy. A particle can convert to a wave and back and forth, at will, when it encounters another field or particle - this is new science for many people... And so when energy is traveling in S-T at speed (C) and there are no external fields acting upon it, it appears as a particle, but when that same energy encounters an external field, it converts instantaneously to a wave field. This explains what happens in the double-slit experiment and also it explains what happened when a particle encounters an atom... Within the atom resonance, the particle converts to a wave field and couples to one or more electron resonance cavities around that atom. Regardless of the speed of the ship, it can always accelerate, because the speed of the reaction of mass converting to energy, is un-effected by the speed of the ship. QED

[@Graywolf116]

6:08 another reason it doesn't make sense to name everything after a person: the Lorentz transformations were discovered by Voigt? It's like the Hessian and Jacobian matrices... one is a first order derivative, the other second order. Calling it a computer makes a lot more sense than "Bob's magic box" especially when Bob stole the idea from Jessica. Love your channel ✨

[@xaverstenliz8466]

🖖...black hole or anti matter are also suboptimal and misleading terms. may the later people should name it because they work the most time with the theory!?

[@peterkiedron8949]

No really. Voigt transform is different from Lorentz transform.

[@dimitrisnatsios8409]

Thank you for your time Mr dialect!

[@HighWycombe]

Does an object that is free-falling towards a large mass (still at low velocity) experience time dilation? I didn't get the answer from Sabina's video, and I didn't get the answer from this one either.

[@mjavada2515]

Relative to what?

[@HighWycombe]

@@mjavada2515 OK, so you've got a clock standing on the roof of a medium tall building on earth. Compared to another clock that is way out beyond earth's gravity, it will be seen to run slow. Notes: - The clock is close to the mass of the earth, and so spacetime is curved. - The clock can be said to be accelerating upwards in spacetime because of contact with the roof. Which of these two things is causing the time dilation? Sabine is saying that it's the SECOND one, but I'm not sure I believe her. To find out, you drop the clock off the roof, so that for a few seconds only the first factor is at play. So, the question is, will the clock continue to run slow during its brief free-fall?

[@use4email878]

@@HighWycombe It is ACCELERATION. Acceleration and gravity are the same thing. That was one of the postulates when Einstein was developing GR. That's what Sabine is saying. The freefalling clock, travelling un accelerated along it's spacetime geodesic will not run slow.

[@HarryHab-w9k]

iff you are in free fall, you are not in a fixed inertial frame

[@Nowhy]

@@HarryHab-w9k who here would mind taking in what you just said? Who would care what it implies and think it through?

[@nirbhay_raghav]

I have just one doubt. If you are saying that time dilation is or maynot be real then how does GPS still work? Maybe it is naive but I drf need the answer because I got more confused after this video.

[@stewiesaidthat]

Clocks measure motion in space. GPS clocks have more motion than ground based clocks because they are tracing out a longer path in space. As the radius of a circle increases, so does its circumference. In order for a geostationary satellite to remain overhead in the same spot, it must travel faster than the ground clock. Electromagnetic waves travel in their own frame of reference. GPS clocks operate at a different frequency (force) because they age experience a different rate of acceleration. Newton's law of motion, F=ma. If the acceleration increases, so must the amount of force. A clock in motion runs slower because the acceleration factor changed but the force factor doesn't. Newton's Law of Motion, the frame of reference is Acceleration. The clock in motion is in a different frame of reference, experiencing a different amount of acceleration. Since it's operating frequency is the same as the stationary clock, you have an instrument that measures relative motion in space. In order to take a measurement, you need a fixed point/constant. The clock's operating frequency is that constant. Since space and time are two separate frames of reference, and clocks are engineered to measure motion on the space frame, the difference in the readouts is strictly due to the difference in motion in the space frame.

[@nirbhay_raghav]

@@stewiesaidthat I appreciate you tried to explain this from the bottom of your heart but all I could see was force frequency and poorly worded sentences. Maybe I am dumb to understand but you clearly need to iron out those sentences mate.

[@stewiesaidthat]

@nirbhay_raghav as simple as I can make it. 1) Space and time are two separate frames of reference. 2) clocks measure motion in space expressed in units of time. Just as rulers measure lengths expressed in units of inches 3) A slower running clock is measuring a greater distance traveled. 4) GPS clocks operate at a different frequency because they measure a different rate of acceleration. 5) Very little is explained about how an atomic clock works, so here are the facts. A).The clock operates at a constant frequency. B) that frequency generates a series of wavelengths that match the circumference of the earth at that given radius for the value of a second. 1/86400th the circumference of a circle. C) As the radius increases, so does the circumference increase, but the value of a second is still 1/86400th the circumference. Only a sundial keeps accurate time as it tracks the position of the sun irregardless of the sundial's planetary location. A mechanical clock does not measure biological processes. Biological processes are not influenced by motion in space in the same manner as mechanical processes. Synchronized clocks measure relative motion in space. How much distance one clock has traveled vs. the other.

[@SubAnima]

Interesting video as always, that teases the debate between realism and anti-realism in science!

[@dialectphilosophy]

Thank you! ❤❤❤

[@creativesource3514]

Who exactly is Dialect?

[@dritemolawzbks8574]

He, she, or they won't reveal themselves.

[@flammmenspeeryt9184]

You are a real hidden gem I swear! You and science clic are the only youtubers I do trust with physics and who's opinion I place above the rest. But I actually got one question. Is there a solution(s) for the twin paradox? It seems like there might be some different interpretations about it. I want to know if there is a objective solution (objective like in the sense that we can measure it) or not. I do not expect a full answer here as you people will probably make an excellent video about it. A quick yes or no would be enough.

[@dialectphilosophy]

The conventional answer to your question is that "absolute acceleration" is responsible for the asymmetry of the twin paradox. So if you have an "accelerometer" with you, you can measure a compression of a spring or something of the sort to know that you are the one "truly moving". We take issue with the conventional answer (as did Einstein) for a number of reasons, including that the notion of absolute acceleration is as problematic and undefinable as that of absolute space or absolute velocity, and that empirical measurement itself is no guarantee of something being absolute or real. Einstein offered up a different interpretation, which we covered in an earlier video, based around gravity (though his interpretation is also somewhat problematic, but for different reasons.)

[@m.c.4674]

​@@dialectphilosophy I think saying acceleration doesn't cause time dilation is contradictory , since as you said it is responsible for the asymmetry . I think you are trying to say it's not responsible for all of the time dilation , which would make Hossenfelder's statement only partially wrong . 12:14 - 13:00 a theory that doesn't have these models , would need aethers () or at the very least a frame of reference for light . Whatever you have planned will probably be controversial , but I think agree that the general public should to know about the alternatives even if the science community doesn't like it .

[@Astro2024]

The twin paradox is not a paradox at all. The twin paradox is a thought experiment in special relativity that involves two identical twins, one of whom goes on a high-speed round trip journey while the other stays on Earth. According to the theory of relativity, time passes more slowly for a moving object than for a stationary one, so when the traveling twin returns, he or she will have aged less than the twin who stayed on Earth. This apparent paradox can be resolved by realizing that the traveling twin experiences two different reference frames, one on the outbound journey and another on the return journey, while the Earth-bound twin experiences a single reference frame. As a result, the traveling twin experiences two distinct stretches of time dilation, which when combined, add up to a smaller total time elapsed for the traveling twin. Therefore, when the twins are reunited, the traveling twin will indeed be younger than the Earth-bound twin. This phenomenon has been observed in experiments involving atomic clocks, and it is a key prediction of the theory of relativity.

[@jimipet]

@@Astro2024 This is the whole point of the video, that if acceleration is not absolute, then what makes the Earth-bound twin to experience a single reference frame? If the Earth-bound twin can say that "whatever happens, I am in a signle reference frame" the same can say the travelling twin. Who is right then?

[@ScienceQuanta]

The Axis of Evil shapes in the CMB is the same shapes as electron orbital shapes however exponentially larger and surrounds either the Earth or the Sun and each multipole in the Axis of Evil reveals a gravity causing particle cloud of either a)the Sun or b) the Earth and is local to the Solar System. This would be the electron related gravity causing particle cloud. The center of the Earth of Sun will also have a nucleus related gravity causing particle cloud. Baryonic Matter accelerates from higher potentials to lower energy potentials within these space time particle clouds through repulsion due to Electrostatic forces, Pauli repulsion and Van Der Waals forces via the larger gravity causing particle clouds interacting with the smaller electron clouds of baryonic matter causing acceleration of baryonic matter away from the higher potentials to lower potentials within the gravity causing particle clouds.

[@Ryan-gx4ce]

Yea, I'm not listening to some random guy on KZbin who claims the entire scientific community has the science wrong without providing a single proof of his claims. I don't care what Einstein thinks about relativity. Science is not religion. Relativity doesnt stand today because einstein made it and we love einstein. Relativity is here today because it has been proven to work, and progress has been made since einsteins time. If you want to disprove relativity you need to provide experiments that demonstrate why a century worth of experimentation proving relativity is true is wrong. Thats science. So if youre going to talk about science, actually DO IT. The universe is not required to make sense to you