'We all move at speed of light through spacetime'.. What does it really mean?

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  • čas přidán 3. 05. 2024
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    We all travel through space time at speed of light. But, what does it really mean? How does it explain the consequences of special relativity - time dilation, length contraction, relativity of simultaneity, and more.
    Chapters:
    00:00 Intro
    01:25 A 2D analogy
    04:15 How to validate?
    07:08 How Pythagorus helps
    08:40 How to piece a website (Ad)
    10:15 Speed in 4D spacetime
    13:30 Why length contracts along motion
    16:30 Simultaneity & clock desynchronisation
    18:17 Revising the Twin's 'paradox'
    19:36 Why 3 spacial dimensions & 1 time dimension?

Komentáře • 1,3K

  • @Mahesh_Shenoy
    @Mahesh_Shenoy  Před 2 měsíci +44

    Head to squarespace.com/floatheadphysics to save 10% off your first purchase of a website or domain using code FLOATHEADPHYSICS
    PS: I made a visual error in the last part. Since the space is shown as 2D, I should have used a flat aeroplane instead of a 3D aeroplane. I saw a question in the comment about what if the object was a sphere? Then it 'turning' wouldn't change the length of the shadow and so length contraction? That can't be right!
    Well, you cannot use a sphere because, again, we are only using two dimensions for space and one dimension for time. So, you would have to imagine a disc. And when a disc turns, it's shadow will contract. Sorry about that oversight.

    • @piyush3836
      @piyush3836 Před 2 měsíci +1

      So does it also applies for black holes as time ticks slower near them ?

    • @JustHackIt1
      @JustHackIt1 Před 2 měsíci +3

      @@Not_a_Physicist I'm from Nepal as well! To multiply two or more physical quantities is basically like combining them (not adding, combining) Area of a wall equals Length times Height is because for each number of horizontal unit there is, there is a unit of vertical as well. The same concept is for physical quantity, for each unit (length, mass, breadth, height, motion, etc) of one physical quantity, when you multiply it with another, there is another same equal unit of the physical quantity

    • @lih3391
      @lih3391 Před 2 měsíci

      @Mahesh_Shenoy Sir, what about the spacetime invariant, (ct)^2-x^2=S^2? I believe this is what you are referring to, but you have forgotten about the hyperbolic geometry of time. This is what makes time different from space right? You can't move freely, only forwards by some amount.

    • @babyoda1973
      @babyoda1973 Před 2 měsíci

      So maybe that's why entanglement seems to move faster we are seeing the actual extra dimension😮

    • @ayushsahoo2078
      @ayushsahoo2078 Před 2 měsíci

      Thats Great, thats mind blowing, keep making videos on such topics and thank you sir, for such marvelous experience!!!!!!!!
      Could you please provide the link for that book?

  • @jellewillems7118
    @jellewillems7118 Před 2 měsíci +91

    You managed to explain an extremely complicated phenomenon like general relativity with just a plane vector, some arrows and a graph so that even middleschool kids could understand it, and it made perfect sense. Like the Einstein, the founder of this whole idea said: "If you can't explain it simply you don't understand it well enough." And you absolutely did. You have my sub, sir!

    • @krzysztofciuba271
      @krzysztofciuba271 Před 2 měsíci +1

      yes? In this case, he died without knowing how to resolve his/P.Langevin's nonsense Twin Paradox (in R.Schlegel, his conversation in 1952, 3 years before his death- in footnotes in R.Schlegels' books).

    • @josephbigler
      @josephbigler Před 2 měsíci +1

      You're explained several topics that have always kind of baffled me. Not only that, you managed to do it without all the complex mathematics that usually goes with them. This is one of the best explanation of all of these topics I have ever seen. Thanks very much.

  • @manasyadav1993
    @manasyadav1993 Před 2 měsíci +282

    That was insane. The last part blew my mind. Probably the best explanation why time can’t flow backwards. Way better than the entropy explanation.

    • @mantrid777
      @mantrid777 Před 2 měsíci +22

      it doesn't mean time can't flow backwards. it actually assumes the particle moves forward in time (i.e. it doesn't explain that, it assumes that). then explains why we/particle don't have access to "time-travel" along time dimension like space but instead see "ghost" of time dimension instead (as clocks). if we assume a particle going back in time, we'll get same conclusions for a backward-time particle.

    • @Rudyard_Stripling
      @Rudyard_Stripling Před 2 měsíci +3

      If you sat on the event horizon in a black hole you would see everything in the past everything in the present and everything in the future all at once. It is written God has this view so he may well have his home in a black hole.

    • @alexb241
      @alexb241 Před 2 měsíci +9

      Actually entropy is a super logical explanation why time flows in only one direction. It is one of the most accessible aspects about the whole theory.

    • @Rudyard_Stripling
      @Rudyard_Stripling Před 2 měsíci

      Actually, if everything goes the speed of light in the 4th dimension then there will be no entropy or death and any decay at all.@@alexb241

    • @the6millionliraman
      @the6millionliraman Před 2 měsíci +14

      @@Rudyard_Stripling Unfortunately for that deity, if it lived in a black hole, it would have zero influence on the rest of the universe because its sphere of causality would be limited by the event horizon of the black hole it lived in.

  • @kcz6865
    @kcz6865 Před 2 měsíci +113

    It turns out that we really do live in Plato's cave, surrounded by the shadows of reality.

    • @abebuckingham8198
      @abebuckingham8198 Před 2 měsíci +6

      Underrated comment.

    • @MartinHabovstiak
      @MartinHabovstiak Před 2 měsíci +4

      🤯

    • @forestvan4915
      @forestvan4915 Před 2 měsíci +9

      This comment is arguably one of the most brilliant on CZcams

    • @bsadewitz
      @bsadewitz Před 2 měsíci +5

      Yeah, that's why the allegory is still fundamental in epistemology. ;-)
      It's not something that turned out; it always was (well, according to Platonists, anyway, but u don't have to be so committed for it to be worthwhile to contemplate). That was Plato's (well, at least Socrates' lol) point. He was using allegory to illustrate
      en.m.wikipedia.org/wiki/Theory_of_forms

    • @abebuckingham8198
      @abebuckingham8198 Před 2 měsíci +7

      @@bsadewitz It's also a reference to the two shadows he uses in the video. That's why it's so clever.

  • @divxxx
    @divxxx Před 2 měsíci +85

    I had read this idea 15 years ago in a book by Brian Greene and it was absolutely fascinating. The idea that Pythagoras could calculate time dilation is insane. It's a very simple idea when you keep it in your head. Once you understand that we are moving at the speed of light through time, everything else makes soooooooooo much more sense.

    • @TheMusicPerson
      @TheMusicPerson Před 2 měsíci +2

      Do you happen to remember the title of the book? I'd love to check it out!

    • @divxxx
      @divxxx Před 2 měsíci +8

      @@TheMusicPerson Sure! It's "The Elegant Universe". Being Green a string theory proponent, it's mostly about that, but in order to present string theory he explains in depth relativity and quantum mechanics too.

    • @krzysztofciuba271
      @krzysztofciuba271 Před 2 měsíci +1

      B.Green Show at World Univ. Festival on Time is a perfect BS for two hours but it provoked me to ...find his nonsense,esp. using another nonsense in Taylor, Wheeler, Spacetime, 1st ed. 1963, where he,by "accident", made a diagram with different "units" of time of a "traveler" on the space-time path! Don't be a fool like them and do homework: make a diagram from the point of view of the "traveler",i.e. you are at ..rest!

    • @Shadowless_Kick
      @Shadowless_Kick Před 2 měsíci +2

      I scanned Greene’s book long time ago, obviously his description did not catch my eyes, now this channel explains spacetime in a very clear and elegant manner!

    • @michele3900
      @michele3900 Před měsícem +1

      *through spacetime, not through time.

  • @Peregringlk
    @Peregringlk Před 2 měsíci +83

    Your channel has rapidly become one of my favourites about science. Your focus on intuition is priceless.

  • @akaHarvesteR
    @akaHarvesteR Před 2 měsíci +78

    Holy hell, the idea of length contraction as a ROTATION of the moving coordinate frame is absolutely mind blowing!!

    • @vyvianalcott1681
      @vyvianalcott1681 Před 2 měsíci +14

      I actually need time to recover from the amount of fundamental shifts of understanding I just experienced, holy shit.

    • @Rudyard_Stripling
      @Rudyard_Stripling Před 2 měsíci +6

      I think the length contraction is a flaw in this, what if the airplane was a round sphere, then it wouldn't matter what angle it is at, no contraction.

    • @Littleprinceleon
      @Littleprinceleon Před 2 měsíci

      If the third dimension in that example/analogy is time, whhat part/property of any object extends in this direction?

    • @akaHarvesteR
      @akaHarvesteR Před 2 měsíci +1

      @@Rudyard_Stripling Actually it would. Calling it a rotation is a bit of an oversimplification. What's really happening is a sort of out-of-round rotation that actually causes the object to skew.

    • @Rudyard_Stripling
      @Rudyard_Stripling Před 2 měsíci

      with a sphere, you can't have an out-of-round rotation lol.@@akaHarvesteR

  • @ArjunA-ln3ov
    @ArjunA-ln3ov Před 2 měsíci +41

    Im a cs major... watching ur videos and other physics videos at my pace after college is the only time of the day I really enjoy

  • @THICCTHICCTHICC
    @THICCTHICCTHICC Před 2 měsíci +20

    Your ability to explain such abstract and complex concepts so simply is genuinely unparalleled

  • @soberskater
    @soberskater Před 2 měsíci +14

    The enthusiasm is contagious! I'm going to read today instead of watching any more screens... great video!

  • @remcodejong9149
    @remcodejong9149 Před 2 měsíci +5

    I understood fairly quickly what the implications of the two dimensional projection was on space time. I completely did not see length contraction coming though, that had me stunned.

  • @meoncrack
    @meoncrack Před měsícem

    I've been on and off other YT videos on this topic for a few years now, and none of them clicked for me until yours. Seriously amazing job. Your genuine enthusiasm and knowledge on these subjects really draws people in. Please keep it up!

  • @NgocBaoM1022
    @NgocBaoM1022 Před měsícem +1

    I found your channel 40 minutes ago and I'm already fallen in love with your contents. Please make more videos, I'm glad that you are the one explaining all of this to us.

  • @gordonhamilton7160
    @gordonhamilton7160 Před 2 měsíci +38

    I love this stuff so much. You do a great job, Mahesh!

    • @Mahesh_Shenoy
      @Mahesh_Shenoy  Před 2 měsíci +4

      Thanks, Gordon :)

    • @williamwalker39
      @williamwalker39 Před 2 měsíci

      ​@@Mahesh_ShenoyWe present an experiment that proves conclusively that information can be propagated nearly instantaneously across space, in the nearfield of an electromagnetic pulse. The experiment consists of a ~30kV high voltage spark generator creating an electromagnetic pulse that propagated 1.5m to a detector. The leading edge of the transmitted pulse and the leading edge of the detected pulse were then compared using an oscilloscope and no time delay within the capability of the scope was observed, where 5ns is predicted if it had propagated at the light speed. The maximum uncertainty in the measurement was 1ns due to noise in the electronics. Since a pulse is digital information. This experiment proves information can be transmitted across space nearly instantaneously. The results is perfectly predicted by Maxwell equations, which yield a wave equation set equal to a source term. Analysis of this equation shows that the phase speed, group speed, and information speed are instantaneous in the nearfield and reduce to the speed of light in the farfield. Below is a link to see a preprint of the paper. We are currently looking for a journal for peer review and publication. The impact of this discovery has implications in both engineering and the foundations of modern physics. The result is completely incompatible with Relativity. Instantaneous signals invalidate Relativity of Simultaneity in all inertial frames and can be used to synchronize all their clocks. In addition, a derivation of Relativity using instantaneous electromagnetic fields (light) yields Galilean Relativity, where time is the same in all inertial frames of reference, and there is no speed limit for mass, fields, and, even light. This can be easily be seen by inserting c=infinity into the Lorentz Transform, yielding the Galilean Transform. This means that if a moving object is observed with farfield speed c light, then Relativistic effects will be observed. But the effects are not real and can be proved by simply changing the frequency of the light, such that instantaneous nearfield light is used, causing the Relativistic effects to disappear. This then proves that the effects of Relativity are just an optical illusion. Since General Relativity is based on Special Relativity, then it has the same problem. A better theory of Gravity is Gravitoelectromagnetism which assumes gravity can be mathematically described by 4 Maxwell equations, similar to to those of electromagnetic theory. It is well known that General Relativity reduces to Gravitoelectromagnetism for weak fields, which is all that we observe. Using this theory, analysis of an oscillating mass yields a wave equation set equal to a source term. Analysis of this equation shows that the phase speed, group speed, and information speed are instantaneous in the nearfield and reduce to the speed of light in the farfield. This theory then accounts for all the observed gravitational effects including instantaneous nearfield and the speed of light farfield. The main difference is that this theory is a field theory, and not a geometrical theory like General Relativity. Because it is a field theory, Gravity can be then be quantized as the Graviton. Lastly it should be mentioned that this research shows that the Pilot Wave interpretation of Quantum Mechanics can no longer be criticized for requiring instantaneous interaction of the pilot wave, thereby violating Relativity. Consequently the Pilot wave interpretation should become the preferred interpretation of Quantum Mechanics due to its deterministic simplicity.
      Electromagnetic pulse experiment paper: www.techrxiv.org/doi/full/10.36227/techrxiv.170862178.82175798/v1
      CZcams presentation of above arguments:
      czcams.com/video/sePdJ7vSQvQ/video.html
      More extensive paper for the above arguments:
      William D. Walker and Dag Stranneby, A New Interpretation of Relativity, 2023:
      vixra.org/abs/2309.0145
      Dr. William Walker

  • @jasonlough6640
    @jasonlough6640 Před 2 měsíci +10

    Dude, that energy at the beginning, you are absolutely an engineer at heart. I get the same way. Theres something special about understanding something, a kind of magic from holding a thought and understanding whats going on. Its exciting, as exciting as a PvP match or playing soccer or riding a roller coaster. Awesome vid.

    • @bsadewitz
      @bsadewitz Před 2 měsíci

      It isn't unique to engineering [such that one could say "you're an engineer at heart" on that basis, tho please understand I am not deprecating engineering]. If one could say any discipline could claim it more than any other, that discipline is philosophy, but I don't really look at it that way--not quite.
      I had an intro philosophy textbook titled "Does the Center Hold?". That comes from:
      "Turning and turning in the widening gyre
      The falcon cannot hear the falconer;
      Things fall apart; the centre cannot hold;
      Mere anarchy is loosed upon the world ..."
      That comes from "The Second Coming" by Yeats.
      en.m.wikipedia.org/wiki/The_Second_Coming_(poem)
      "The poem uses Christian imagery regarding the Apocalypse and Second Coming to describe allegorically the atmosphere of post-war Europe.[2]"
      It's also the title of this book, just to give you another example of the theme:
      en.m.wikipedia.org/wiki/Things_Fall_Apart
      I'm sure you can see the applicability of the metaphor to understanding writ large.
      Indeed, consider the word "understand" itself. One could literalize it as standing under something--in awe.

    • @bsadewitz
      @bsadewitz Před 2 měsíci

      The opposite of things falling apart is the integrative project of science, or generally seeking a coherent body of knowledge about the world, which science is a part of. And obviously physics plays a fundamental role in this project. Whether physics as it is constituted today will always be considered the MOST fundamental remains to be seen, as one may argue that the only thing that we actually have access to is consciousness itself. And nobody knows for sure what that (or perhaps THIS) even is, or whether we are even capable of coming to grips with that. I like to think so, but we don't know ...

  • @piyushpathak1186
    @piyushpathak1186 Před 2 měsíci +9

    Ohh bhaii @21:05 explains why we can't move back and forth in time
    Because it's length contracted 🤯🤯🤯

  • @sgiri2012
    @sgiri2012 Před 2 měsíci +17

    How passionate you are. You are dedicatedly explaining the topics.
    Iam all ears when you are speaking because it's so exciting to hear. To top it all, your facial expressions gives positive energy for the topic and made us feel good. You are explaining all the intricate details of the topic which is so good.
    Oh my gosh, Despite you have crossed 1 lakh subscribers, you are still posting one video per week. Please try to make your folks engaged throughout the week.
    Sooner or later, this channel should be flooded with the hoards of people and zeptillion of videos. My dream will come true.
    P.s. please teach us about tensors. How it can be felt under the bones ?
    I think you are the right person for explaining this thing.
    Who all want about tensors ? Please give thumbs up for this comment.

  • @PegLegKegCraig
    @PegLegKegCraig Před 2 měsíci +3

    “(The 4th) dimension is length contracted to zero” This is such a beautiful explanation. We’re just along for the ride like a fish in a tidal wave.

  • @iceseic
    @iceseic Před 2 měsíci +6

    Mahesh your channel is what I truly need deep down in my heart! Years ago I questioned do light experience time (which you answered years later), and back then that question drown me in my own postulate and thought experiment that also lead me to think we travel through time at C and whatnot. Even the use of shadow analogy that manifested in our space world that can be observed, but man your explanation and visualization actually make a clearer implication of this way of approach and many things I never thought of despite thinking the same thing ❤❤

    • @iceseic
      @iceseic Před 2 měsíci

      It was pure hype when you explain the length contraction

  • @raezuk
    @raezuk Před 28 dny

    Love this video.... you totally walked back and ran through some of some of my misgivings on previous things I've seen from you. Perspective is really the key.

  • @jakobo8908
    @jakobo8908 Před 2 měsíci +6

    i love this channel so much, for someone interested in physics but who has no academic experience those explanations that everyone can understand are so perfect

  • @squidwardstesticles5914
    @squidwardstesticles5914 Před 2 měsíci +4

    This is probably one of the best videos for understanding relativity I’ve ever seen

  • @anjin77
    @anjin77 Před 2 měsíci +3

    The first time this really 'clicked' for me was reading Brian Greene's "Elegant Universe" years ago where he used the example of a car that only goes 100 mph, and how the velocity must be 'spent' in other dimensions/axes when not driving in a perfectly straight line.
    In the book's appendix he expanded on this basically using simple vector mathematics. Once you picture x^2 + y^2 + z^2 = magnitude^2 in 3 dimensioal space, then it's not much of a leap to determine that x^2 + y^2 + z^2 + t^2 = c^2. And since our movement in three-dimensional space is comparatively very slow, then the rest of our magnitude through spacetime must be 'spent' in the t dimension. That was a huge 'light bulb' moment for me that day. Good stuff!
    What was a new light bulb moment for me in this video was your visualization for length contraction. Thanks!

    • @adlikfasadlikfas9531
      @adlikfasadlikfas9531 Před 2 měsíci +1

      Something clicked in me while reading your comment: we say that kinetic energy is dependant on velocity and mass (as in E=mv^2/2) so using that logic and the way you made equation we can say that E=mc^2 is basically our kinetic energy in spacetime. Of course this logic might be flaved but it still sounds awsome.

  • @bernstock
    @bernstock Před 2 měsíci

    My man! That was an epic video!! I never thought to just crunch down the 3 spatial dimensions into one perpendicular time… what a great way to explain it. Last bit was awesome, STRONG FINISH 💪🏼
    Loving your videos, keep em coming!

  • @SimonThwaites
    @SimonThwaites Před 2 měsíci +5

    This is a fantastic video, thank you - only the latest of a tremendous series that has become a must watch with each new one. The thing I struggle with is whether ideas like this - in this case that everything moves with the same speed in 4D and that our experience is a ‘projection’ in 3D with a ‘phantom’ length contracted spatial dimension which represents time - are actually meaningful as descriptions of how the universe really is, or if they are instead very clever analogies and images that exploit superficial similarities between systems that are characterised by ratios between two numbers.

    • @juliavixen176
      @juliavixen176 Před 2 měsíci +2

      The atoms of our bodies and all other material objects are held together with electrostatic force... basically, "light". We are partially made of light, and so parts of us are propagating at the speed of light... you are always traveling at the speed of light and you can't go faster than yourself. Atoms and molecules are basically microscopic light clocks.
      The really important question that always gets skipped over in explanations of Relativity is: " _Why does anything travel _*_slower_*_ than light_ ?" And the answer is confinement, it's where "E=mc²" comes from... and I don't know why it only gets covered in colledge physics classes and not CZcams videos. Anyway, it's the origin of inertia (mass), and why "time" and "space" have any distinct meaning.

  • @abhaychordiya6489
    @abhaychordiya6489 Před 2 měsíci +30

    Is that the Minecraft grass block as the floor😂😂
    That's nice

    • @Mahesh_Shenoy
      @Mahesh_Shenoy  Před 2 měsíci +16

      Honestly, I just picked the first free photo I could find :D

    • @smithstudiertetwas8914
      @smithstudiertetwas8914 Před 2 měsíci +1

      Yes that definitely is the Minecraft grass block loll

    • @Snakyy1
      @Snakyy1 Před 2 měsíci +3

      It’s not minecraft block textures are 16x16 this is double that

  • @garylcamp
    @garylcamp Před 2 měsíci

    I asked "Starts With A Bang" a year or so ago about why we are moving through time at 1 sec/sec which I noted was 186,000m/s but I got no answer. You have really shown me more than I asked for. By far! It is truly wonderful. I can see why you are so excited. Great presentation.

  • @knubswak
    @knubswak Před 2 měsíci

    Love your energy, friend. I also get excited in much the same ways when super deep concepts suddenly click. It feels like my consciousness suddenely balloons and knowledge comes rushing in.
    Always keep the good feelings flowing!

  • @crow2989
    @crow2989 Před 2 měsíci +4

    Is this why it’s said that photons traveling at light speed don’t experience time? All of their Velocity is in Space and little to none is in the Time Dimension?

  • @AdarshRaj-fj4fw
    @AdarshRaj-fj4fw Před 2 měsíci +7

    What does it mean by the ,term speed in time dimension.. I mean even in spatial dimensions don't you have to include time as well to measure (or define) speed in the first place?

    • @dismalthoughts
      @dismalthoughts Před měsícem +1

      It's quite simple, really. In that 4 Spatial Dimension area, where _our_ concept of time is really just a spatial dimension through which a 4D entity is traveling at the speed of light, there's a 5th Temporal Dimension. And that 4SD entity, of which we are its shadow, is a shadow of a 5 Spatial Dimension entity which is traveling through one of its 5 Spatial Dimensions at the speed of light, which then becomes _its_ 6th Temporal Dimension -- its concept of time. So really, that 5SD entity is a shadow of a 6 Spatial Dimension entity...

    • @tintun8918
      @tintun8918 Před 21 dnem

      Speed just becomes a ratio of two spacial units. It is like how you can say, "That house is 3 units north and 1 units east." Speed will be like 1 unit in spacial part of space time over 1 unit in temporal part of it.

  • @himeshph
    @himeshph Před měsícem

    "If it's just told, I don't like it, I want to discover things myself and piece things together and come with conclusion myself." - Mahesh
    The above quote is powerful. 👌

  • @JohnGalt0902
    @JohnGalt0902 Před 2 měsíci +1

    Great job! The best explanation of why only 1 time dimension. And loved the picture demonstrating the 3 consequences. Keep it up!

  • @london8732
    @london8732 Před 2 měsíci +9

    Hi Mahesh, great video.
    In the part that explains the twin paradox, you stated that the twin sister moves through space, so she loses some of her velocity through time, making her younger when they reunite.
    Wouldn't it be the case that from her perspective, she is at rest, and her twin is the one that moved through space. So when they reunite, she would expect that her twin was the younger one.
    If it is just about the relative motion through space, then I don't see how this resolves the paradox.
    It explains time dilation from both subjective perspectives, but the paradox remains as both would expect the other to be younger from their frame of reference.
    This is not a criticism, I think this video was fantastic. It's just that I feel like I've missed something here.

    • @pavandn
      @pavandn Před měsícem +3

      Yes, I haven't come across any convincing explanation for twin's paradox so far. All the explanations deviate into answers that don't explain the fundamental problem. The actual question we should be asking is : "Between two objects that are in constant relative motion, which one sees time dilation and length contraction". If we can't do an experiment to determine who is moving as per the theory, then the time dilation for only one of the objects disproves this statement, as we can simply compare the clocks and see who moved !!

    • @sudhakanthagirmohanta5695
      @sudhakanthagirmohanta5695 Před měsícem

      You should take into account the relativity of simultaneity and really ask what this question of age means from each reference frame. Mahesh already made a nice video regarding that.

    • @drfisheye
      @drfisheye Před 11 dny

      The perspectives of the twins aren't the same. One twin moves away, then changes direction and comes back. The other doesn't change direction. That's a measurable difference. If both would be constantly throwing a ball in the air and catching it, the twin that moves, then changes direction and comes back would lose her ball, because the ball would continue in the first direction (try throwing a ball in the air while you change the direction of your car, you will lose the ball). The twin that stayed stationary would never lose the ball, because she didn't change direction. So there is no symmetry between the twins movements. That's why one will be younger than the other one and they can observe the difference themselves.

    • @pavandn
      @pavandn Před 11 dny

      @@drfisheye What if the space time is curved such that he doesn’t have to change direction and meets his twin after travelling in straight line?

    • @drfisheye
      @drfisheye Před 10 dny

      @@pavandn the Twin paradox is about special relativity, not general relativity, so there is no curvature involved. Even so, if there would be curvature then if the stationary twin would let go of a ball, it would fall down. If the twin in orbit (because of the curvature) would let go of a ball, the ball would continue to move with the twin. So that situation isn't symmetrical either.

  • @PhysicsConcept-cd1bi
    @PhysicsConcept-cd1bi Před 2 měsíci +5

    Keep making this kind of videos which have a different prospective to visualise the physics. We appreciate you for it!

  • @jameswebb3410
    @jameswebb3410 Před 2 měsíci +1

    One of the best(if not best) explanations of complex concepts I've ever come across on the internet.

  • @remcodejong9149
    @remcodejong9149 Před 2 měsíci +9

    This may be the best explanation of special relativity I have ever seen.

  • @benlap1977
    @benlap1977 Před měsícem

    Your enthusiasm is contagious! And I cheered when you showed where length contraction came from!

  • @dhrubajyoti53
    @dhrubajyoti53 Před 2 měsíci +1

    My mind was totally blown away... I never thought I could ever get a real perspective and physical significance of relativity.... Thanks for this awesome video...

  • @brianr8081
    @brianr8081 Před 2 měsíci

    Incredible video. I kept having these incredible breakthrough realizations, it would just click, only to flicker out seconds later....but I'll watch this video dozens of times. I can't believe these analogues really exist, that is so freaking cool.

  • @user-fv3uf9kz2t
    @user-fv3uf9kz2t Před 2 měsíci

    Ive watched a ton of these types of explanations and this video is by far the most intuitive teaching of a very difficult subject. Hats off to this teacher. We will see more of him.

  • @seabeepirate
    @seabeepirate Před 2 měsíci +1

    The illustration was well done. I’ve been imagining dimensional projections for a while. Very neat to see them in action.

  • @jdog987
    @jdog987 Před měsícem

    Yo! This is such a nice way to think about it, placing time on an axis and looking at the projection.
    I also loved the 'photon clock' on a cart analogy, not only did that perfectly describe time dilation, it also demonstrates how you can think of light as a particle and a wave.
    Great video my guy!

  • @jgri1324
    @jgri1324 Před 11 dny

    It is so much fun to watch someone as excited as I was during my preteen and teen years explaining this kind of complicated physics with such intuitive examples :-) really makes my day!

  • @DxvidEisboerg
    @DxvidEisboerg Před 2 měsíci +2

    You're the best teacher i could imagine like really you explain things so intuitively that i now have a much better understanding about relativity.
    And i wanted to ask if you could make a video where you just broadly explain general relativity

  • @krek17
    @krek17 Před měsícem

    I am just trying to imagine what are we projections of, and man this explanation, with the graphs, and pythagoras, all so simple, and you said it, wrapping your head around. Good video!!

  • @nemanjastankovic6444
    @nemanjastankovic6444 Před 2 měsíci +1

    Man, thanks for the vids you do. Every time i understand you fully, and every time it's like you opened a door that didn't exist. Just wanted to say thanks.

  • @masoodakram1950
    @masoodakram1950 Před 2 měsíci

    Sir, I'm being very greatful to god that I discovered your channel. I never felt the same enthusiasm even during my graduation studies.

  • @masai2
    @masai2 Před 2 měsíci

    Wooooow! Your animation with the plane and its shadow explains more than dozens of books and films I have read and watched in my life. Grats!

  • @jorgejorge8878
    @jorgejorge8878 Před 2 měsíci

    Your happy energy and excitement matches exactly what I feel about this subjects. Thanks for the great content.

  • @voldy3120
    @voldy3120 Před měsícem

    There had been times when I wished time just froze (not from embarrassment but from emotional reasons).
    I sort of fantasized it to the extent that I started to wonder how things would appear and behave if I moved.
    Now a few years forward in time, I don't have no more need to freeze time or fantasize about it but that question still comes to my mind.
    This is how I truly got intersted into theory of relativity.
    And sir from Khan academy to this you have been a great source of inspiration and great help. Thanks alot.
    And please keep the series going.

  • @bensyversen
    @bensyversen Před 2 měsíci +5

    What a great video. This really helps me to understand this stuff better as I've been trying to wrap my head around it recently. Thank you!
    Here is a great historical detail that you might enjoy: this mathematical description of space-time didn't originally come from Einstein. It actually came from mathematician Hermann MInkowski, who was Einstein's math professor in college (Einstein didn't take math very seriously at that time and tended to skip class). After Minkowski presented these ideas, Einstein was initially skeptical. He called it "superfluous erudition" and wrote that "since the mathematicians have grabbed hold of the relativity theory, I no longer understand it myself!" Einstein thought the fancy math obscured the beautiful physics.
    But he eventually came around when he realized just how powerful a tool this was for understanding the idea and making new predictions.
    Cheers!

    • @DrDeuteron
      @DrDeuteron Před 2 měsíci

      well, he never could have formulated General Relativity w/o Minkowski, since its Minkowski's 4D spacetime that gets curved. I have never seen a GR formulation without it.

    • @bensyversen
      @bensyversen Před 2 měsíci

      @@DrDeuteron yes, this was Einstein's reaction to Minkowski's work in 1908. As you say, it wasn't long before he realized that he couldn't formulate general relativity without it.

  • @PaulThatcher-iu5in
    @PaulThatcher-iu5in Před 2 měsíci +5

    Mahesh, you say you're still having trouble wrapping your head round it - yeah, I know the feeling. I mean, I understand the points made here, I see why time dilation, length contraction, and the relativity of simultaneity flow from the idea of our 4-velocity being c - I even see why spatial dimensions are traversible in both directions, but time is not. However, I just know that this feeling of understanding will be blown away by the next, deeper realisation of the beauty of this explanation. And that's what's amazing in Relativity: no matter how long and hard you look at it, it just keeps getting more beautiful in its simplicity.

    • @DrDeuteron
      @DrDeuteron Před 2 měsíci

      "it just keeps getting more beautiful in its simplicity."
      Physics in a Galilean universe would be a mess.

    • @angeldude101
      @angeldude101 Před 2 měsíci

      @@DrDeuteron Physics in an elliptic universe wouldn't have time, since the spatial dimensions are already elliptic. If it did have time, then accelerating enough would let you go back in time.
      Galilean relativity at least maintains a distinction between space and time, though the 0s that can pop up can make things weird.

    • @helifynoe6956
      @helifynoe6956 Před 2 měsíci

      Not the next deeper realization, but the one from the past. I threw some vids together 10 years ago that use a geometric representation of "c" motion within space-time, (a geometry composed of the combination of motion vectors and length scalars), all to explain special relativity and at the same time it is used to derive the SR mathematical equations, and derive the Lorentz transformation equations, with each derived in the most simplest and quickest way ever possible.

  • @hgracern
    @hgracern Před 2 měsíci

    Wow, I so want to follow you. Just the first few mins has taken me umpteen pauses. I can’t be the only subscriber who craves a seque or comma/full stop every few sentences. ❤

  • @ashwinishenoi2642
    @ashwinishenoi2642 Před 2 měsíci

    Thank you Sir. Your knowledge and ability to explain things is so amazing.

  • @terrycrooke1
    @terrycrooke1 Před 2 měsíci

    Just discovered your channel ... you're enthusiasm shows no bounds.... awesome job

  • @Juss_Chillin
    @Juss_Chillin Před 2 měsíci +1

    This was insane to watch and realize yourself. You explained it SO good! Thanks so much for this vid. Love it :D

  • @vikasmorje
    @vikasmorje Před měsícem

    incredible explanation, I went crazy. Out of my interest in Physics, I have been reading about this subject, especially space time and light, since 40 years back on and off. The best visualization of complex subject in a simplest way for dummies like us, hats off. Thanks!

  • @horseios3655
    @horseios3655 Před 2 měsíci

    This is easily the best video you have ever published on this channel. Well Done!

  • @mreclecticguy
    @mreclecticguy Před měsícem

    Wow. You explained a complicated idea in such an intuitive and visual way that it was easy to follow the logic.

  • @AndrewSchiessl
    @AndrewSchiessl Před 2 měsíci

    I absolutely love your enthusiasm! Your videos are so much fun and I learn amazing things!

  • @rustyspygoat4089
    @rustyspygoat4089 Před 2 měsíci +4

    This channel is incredible. Exactly what I have been looking for...

  • @maryannematthews7176
    @maryannematthews7176 Před měsícem

    Wow 🤯 I’ve been watching videos about this for a while now and this is the first time I’ve had even a flicker of understanding. Truly mind blowing.

  • @kaushiksarkar6761
    @kaushiksarkar6761 Před 2 měsíci

    What a wonderful video! Nicely explained with simple diagrams. Great great job 👏👏👏. Your channel has become one of my favourites now. Thanks for these insights. 👌

  • @ErvaarT809
    @ErvaarT809 Před 2 měsíci +1

    Wow you are a hero. I started studying by myself at 30 because I couldn’t memorize anything at school in the past. And with time I realized that it was because they weren’t teaching correctly. I was scared of gravity, light…and all because I knew that they were controversial subjects and I didn’t have time to discover everything by myself so thank you very much to you and to the author of the book.

  • @uavtech
    @uavtech Před 2 měsíci +1

    WOW. This is amazing! What a great insight on pulling back the curtain. GREAT JOB!! and thank you.

  • @johnbrouillet988
    @johnbrouillet988 Před měsícem

    My mental model for GR has been to think of any given object or particle having a total energy budget for movement through spacetime that stays constant, and so when it moves faster in either space or time, it has to draw energy from the budget for movement through the other domain. A kind of zero sum game scenario; to accelerate in space requires slowing movement through time, and vice versa.
    The key is realizing that it takes phenomenally more energy to move through time, because it’s got a sort of rigidity due to only being able to “flow” in one direction, so that for any practical reference frames that we as humans experience, our changing velocity in space makes virtually no difference in our velocity down the time dimension. It only becomes apparent when we study objects or particles that have been accelerated to nearly the total energy budget’s expenditure in movement through space.

  • @Conradd23
    @Conradd23 Před 2 měsíci

    This was an excellent explanation! Thank you for coming up with this!!

  • @ufuk5396
    @ufuk5396 Před 2 měsíci

    This concept blowed my mind in major classes too. Glad someone talked about that.

  • @joske7804
    @joske7804 Před 2 měsíci

    This is totally awesome. A really cool explanation, I almost can't believe it. The shear intuition this gives is mind bogling.

  • @anjin77
    @anjin77 Před 2 měsíci +2

    You are an exceptional teacher and communicator, inspiring others with your passion. I wish you much success, happiness and fulfillment! Thanks for providing such great content Mahesh! Subscribed.

  • @imagiro1
    @imagiro1 Před 24 dny

    Not sure what I like more: Your explanations or your excitement :)

  • @akphotodesign
    @akphotodesign Před 14 dny

    Thank you! This explanation makes it so digestible.

  • @Roman_Bo
    @Roman_Bo Před 2 měsíci +1

    Besides this can you explain in this strategy such questions:
    1. What's about quantum tunelling?
    2. What's about expanding of universe (faster then speed of light)?
    3. What's about undefinision of microworld?

    • @Roman_Bo
      @Roman_Bo Před 2 měsíci

      and 4. quantum teleportalion

    • @Roman_Bo
      @Roman_Bo Před 2 měsíci

      And the main:
      5. If evething is moving with the speed of light, then IN WHAT FRAME? These's might be some coordinates relative to which we move with the speed of light?

  • @kylelieb2977
    @kylelieb2977 Před měsícem

    Wow. This was literally the best explanation of spacetime and relativity that I have ever seen. Def Saving this one.

  • @sunilgokhale
    @sunilgokhale Před měsícem

    Super explanation....clears the basic concepts of space-time

  • @showyourteeth2180
    @showyourteeth2180 Před 2 měsíci

    watching you explain this, makes me happy. And on top of that, I understand now. Thx

  • @knightvalour1275
    @knightvalour1275 Před měsícem

    I love how excited you get sharing info

  • @yoteach
    @yoteach Před 2 měsíci +4

    Awesome animations of this idea! It becomes even more intuitive if you replace "c" with the "speed of causality" rather than light. Then light, gravity - anything not anchored to spatial dimensions by mass - travels at the speed of causality: the fastest way information get from one point in spacetime to another point.

    • @sevenstarsofthedipper1047
      @sevenstarsofthedipper1047 Před 2 měsíci

      I am not a scientist nor was I a science major but, I thought that he was going to say that Gravity was a consequence of an object diverting some of its speed in the spatial direction because it looked like the plane was nosediving back into the ground the more it diverted its motion to the spatial direction.
      But he didn’t say that so, I am probably not really understanding what he is saying.

    • @sylfthesoundyoulongfor8363
      @sylfthesoundyoulongfor8363 Před 2 měsíci

      @@sevenstarsofthedipper1047 Gravity IS Indeed a conséquence of spacetime deformation. Check PBS "IS Gravity an illusion l'' on that matter

    • @sevenstarsofthedipper1047
      @sevenstarsofthedipper1047 Před 2 měsíci

      @@sylfthesoundyoulongfor8363 Are you saying that the “deformation” in spacetime we call Gravity is caused by mass in motion inside a moving Universe? So, then what is spacetime made of? It must be made of something, otherwise, this SR model makes no sense. Something has to generate the shadows that are used to explain length contraction in this model?

  • @osaimola
    @osaimola Před 27 dny

    7:58 love how this clearly illustrates time as a spacial dimension.
    Which should mean time travel is possible.

  • @sherrinisadumbass211
    @sherrinisadumbass211 Před 9 dny

    your enthusiasm is truly infectious, I was on the edge of my seat the entire video what an incredible explanation :0

  • @anonymous12574
    @anonymous12574 Před 2 měsíci

    Hii Mahesh!
    I found your videos to be quite interesting and very informative for a physics nerd like me .
    I would like to see a video on retroreflectors and its applications . Those are quite important invention nowadays..
    Lots of support 💪

  • @artb4700
    @artb4700 Před 23 dny

    Thanks for the excellent explanations and your enthusiastic presentation. Enjoyed this 😊.

  • @TommyTheMooch
    @TommyTheMooch Před 2 měsíci +1

    Amazing way to illustrate spacetime. I'm once again excited after being bored with other methods.

  • @lorisklaws9612
    @lorisklaws9612 Před 2 měsíci

    hey dude i just wanna say i really like your videos, really great energy coming from you

  • @Rudyard_Stripling
    @Rudyard_Stripling Před 2 měsíci +1

    Sweet, without your help I doubt I could have understood this just from the book. Incredible and amazing.

  • @AmirbekIslomov-ih2xx
    @AmirbekIslomov-ih2xx Před 4 dny

    @19:57 The reason why the length is contracted is that the object is rotated in some higher dimension. So if the length is contracted to zero in the fourth dimension, there must exist a higher dimension in which the particle is rotated. I

  • @conormadigan7829
    @conormadigan7829 Před 2 měsíci

    Man I love this channel. It’s very hard to find these concept explained so simply and completely. 👏

  • @sergekannon9048
    @sergekannon9048 Před 2 měsíci

    This video brought tears to my eyes I will not because it's beautiful, but because I had used my own thought experimentation to come to the same conclusion years ago. Yes! When we travel at the speed of light in any direction, we lose that dimension dimension and it becomes a temporal one. That means there are infinite spatial and temporal dimensions. There are temporal dimensions in every direction an wkectron can travel and each of those temporal dimensions will have its own spatial dimensions that are not the same as ours. I imagine this is how there are infinite universes right within our own universe.
    I also imagine it as if when you're traveling at the same speed and direction with photons, you experience the energy of those photons as matter.
    You've earned a lifelong subscriber. You are truly a high genius!

  • @jnjairo
    @jnjairo Před měsícem

    Finally a good simple explanation, I saved it for when I need to explain it to someone. The pythagorean theorem is underestimated, it is a powerful tool to understand the universe as shown in this video.

  • @Raj-yv7xt
    @Raj-yv7xt Před 2 měsíci +6

    after seeing this video i would recommend to move around alot ...so that u r moving slower in time's axis and thus live more than the people of the same age...

    • @divxxx
      @divxxx Před 2 měsíci +6

      You don't actually live longer, you can simply delay your death with respect to others. Don't forget that from your own perspective you are at rest, therefore your clock is ticking normally.

    • @kylelochlann5053
      @kylelochlann5053 Před 2 měsíci +3

      There is no "time axis" in the world to move relative to - there are only the world-lines of objects.

    • @Raj-yv7xt
      @Raj-yv7xt Před 2 měsíci

      @@kylelochlann5053 i am sorry i don't have proper words to say my thoughts...but what I wanted to say is like even if the one moving doesn't feel anything different in time he experiences... but as a third person we know that the one traveling or moving is experiencing time dilation and will not age similar to that of a person stationary or consider on earth....one traveling will experience the time normally but he can know in his head that he is experiencing time dilation and when he meets his counterpart he will be younger than him..and when i mean at rest or stationary it is all relative ...in this intuition of his he says everything is moving at max. Speed ..i.e light speed ..so if we consider relative velocity we r all at rest ...or constant velocity..which we can't differentiate...time axis and all is intuition we just move through time but the time itself is measured by motion of something(photon)....but yes that's what i wanted to tell...so i said even if insignificantly small..if u move alot then u will age late or die after ur twin or any other counterpart....

    • @THICCTHICCTHICC
      @THICCTHICCTHICC Před 2 měsíci +1

      At best you might somehow snag an extra femtosecond or something

    • @Raj-yv7xt
      @Raj-yv7xt Před 2 měsíci

      @@THICCTHICCTHICC yep..ik that...but man even a part of second matters...😂

  • @Khantia
    @Khantia Před 11 dny

    2:40 I do see a flaw with this analogy, which can be seen later on in the video, but isn't explained.
    As we established, if an object has a constant speed through spacetime, if it's directed to move entirely through space, and none of it is dedicated to move through time, then from the perspective of the shadow people, they will see the plane standing still, then it will start moving fast (without having accelerated before that) and in the end of the second second, it will just... start existing at several places in the same point in time.
    I'm not sure, but I think I've watched other physics videos talking about the same thing, but they put the speed of light to be at 45 degree, not 0, as it's shown in this video.

  • @Cliff_P
    @Cliff_P Před měsícem

    Finally! I used to use the example a block of matter in a empty universe with a powerful rocket motor that ran and then burned out, with the time frame change always being negative with the introduction of kinetic energy. And also a satellite orbiting Earth with the gravity being slightly more on the near side of the craft versus the outside of the craft causing a relativistic time difference. Your explanation clarified everything.

  • @Bored_Miss_A
    @Bored_Miss_A Před 2 měsíci +6

    Wow! I need sometime to ponder on all these. Thanks for your effort making this video.

    • @Mahesh_Shenoy
      @Mahesh_Shenoy  Před 2 měsíci +1

      You're so welcome!

    • @Rudyard_Stripling
      @Rudyard_Stripling Před 2 měsíci +1

      I think the length contraction is a flaw in this, what if the airplane was a round sphere, then it wouldn't matter what angle it is at, no contraction. Am I right or wrong?@@Mahesh_Shenoy

    • @bobspongieux
      @bobspongieux Před 2 měsíci

      Tell that to Elon and we'll have spherical rockets

    • @Rudyard_Stripling
      @Rudyard_Stripling Před 2 měsíci

      We have spherical UFOs already and they could definitely be made purely spherical lol.@@bobspongieux

    • @juliavixen176
      @juliavixen176 Před 2 měsíci

      ​@Rudyard_Stripling I wish he would just lookup Terrell Rotation. Length contraction doesn't actually make things *look* smaller... Also lookup Born Rigid Body Motion too, because all this "Introduction to Special Relativity" stuff is neglecting to mention that it's only describing *points* in a 1D line, and not extended 3D objects.

  • @AnkitRathi7
    @AnkitRathi7 Před 25 dny

    That was incredible, that's the best explanation where I could visualize four dimensions. I just couldn't before watching this video.

  • @Creepyslandofdreams
    @Creepyslandofdreams Před 2 měsíci +1

    Your raw passion makes me so happy. Never change.

  • @Jake-co7rt
    @Jake-co7rt Před 2 měsíci

    Visualizing Relativity is a wonderful book.
    I read it years and years ago, cause I really wanted to understand it.
    It was super-clear and easy to follow. I still have that copy on my bookshelf.

  • @lincolnkaden7758
    @lincolnkaden7758 Před měsícem

    What a brilliant explanation!
    So intuitive. Thank you

  • @DM-jo5ko
    @DM-jo5ko Před 21 dnem

    Always impressed with your videos. Just when I thought I had a good grasp of physics, you show me this! Wow!

  • @louisalfieri3187
    @louisalfieri3187 Před měsícem

    When he turned first the plane! Chef’s kiss!!! I have a masters in physics and can say Great Job. I love this guy.

  • @innsaanitty
    @innsaanitty Před 29 dny

    Your channel is absolutely amazing!