Einstein was once asked why he was not able to finish his grand theory of everything. He replied there was this Indian guy calling him every other day.
Did not understand this as an undergrad over a half-century ago. Went on to get PhD in math a few years later and had a 45-year career as a math professor, never really understanding this.... And now? This presentation was Magnificent! Thank you so much! OH, AND YES! PLEASE DO SHOW THE ALGEBRA/ GEOMETRY IN A FUTURE VIDEO!
Still doesn't really explain it. Just gives a new prohibition "no test exists to determine what reference frame is moving at constant velocity." Which is less intuitive than the simple fact light moves at the same speed regardless of reference frame velocity. Why is it impossible to know and why is light a fixed speed limit.
We need to get this guy to 1m subs. I watch a ton of science communication channels, all the heavy hitters, and this guy far and away does the best job of walking through these problems in an intuitive way.
Shame that Einsteins hypothesis is totally wrong. I mean it has unrecoverable errors that make the theory impossible nonsense. No one cares enough to discuss what the problems are. They are happy to believe the irrational.
though much simpler explanation is that speed of light is not about light but about causality, and since light is a gauge boson, carrier of e/m interaction (i.e. causality), and since interaction defines time itself - it's by definition that speed (which is derived from time) of light is the same in all inertial frames of reference
@@z08840 The speed of light is the speed of light. "Causality" is an abstract idea, not something that you can measure how fast its moving. Stop mixing up fantasy concepts with real Physics. There is no such thing as a gauge boson, that is also an idea. And a silly one at that. The measure of light speed is NOT the same in all frames of reference, that fantasy is irrational.
When I was younger, the example at 15:25 boggled my mind, thinking that the speed of a spaceship and the light emitted from the spaceship's headlights would add up, and should be faster than the speed of light. LOL Silly me, now we know that the speed of light appears to be the same for all observers, both on the ship and the outside.
Evidences for Varying Speed of Light with TimeGiuseppe Pipino Technical High School, ITIS Malignani, Udine, Italy. DOI: 10.4236/jhepgc.2019.52022 PDF HTML XML 836 Downloads 3,392 Views Citations Abstract Aims: The paper explores the hypothesis that the speed of light c is decreasing over time at rate (dc/dt)=-H⋅ c, H being the Hubble constant. This hypothesis differs from the so-called tired light, in which the velocity c is supposed to vary during the journey of photons in the empty space for some frictional mechanism. In the hypothesis of the author the speed c, during this journey, is assumed constant. In this way the problems of the tired hypothesis are overcome. Methods: The paper links the variation dc/dt with the Hubble constant and infers a value of dc/dt from the difference between the value of the variation of the Earth-Moon distance measured by the Lunar Laser Ranging Experiment and the tidal effect. Results: Under the hypothesis c time varying, we explain: 1) The cosmological redshift. 2) The anomalous acceleration ap ≈ -8 × 10-10 m⋅sec-2, measured for some spacecrafts. 3) The high redshift of supernovae Ia, which seems to evidence an acceleration of the expansion of the universe. 4) The peripheral motion of stars in galaxies around their rotational centre. 5) The dilation of the light curves observed for supernovae Ia.
This is why Einstein said "Imagination is more important than knowledge". I'm proud of myself!! 🤓Today, for the first time in my life, I imagined outcomes of special theory of relativity. Thanks Mahesh. Please do the next part of the video.
If I were the judge, I would have countered your argument at first instance by telling you that the question is not about who was in motion but who caused that motion to happen. So It was you who caused the motion of your surrounding. 😀
indians helping random youtubers is stepping up from voice and notepad text tutorials to this masterpiece. sir u answered the questions i had been looking for in such an elegant way i salute you
@@Brianboru-k8y it is not a medium, if it is a medium what is this medium made of ? a medium is a field of material/matter what waves propagate in spacetime is not that
I think what makes this so hard is that we have adopted the phrase “speed of light” for c. If we'd called it the “speed of causation” and then said _it turns out_ that in the absence of a medium, light moves at the speed of causation, it would be much easier to wrap your head around. Indeed, it also opens the door for the (it turns out) meaningful question of _why_ light should travel at this speed-because light does in fact have relevant properties that other phenomena don't. But “why does light travel at the speed of light?” invites no such exploration.
I never really truly grasp the true meaning of the special relativity, until i watched your video. Your style of teaching is really intuitive and easy to follow, even on complex topics. Love your work, and keep doing what you're doing, cheers.
I have never understood more about special relativity than I do now after watching your video. You are hands down the best science teacher I have ever seen. And I subscribe to every science channel on UA-cam. The first time you blew my mind was your explanation of angular momentum and electron spin. Now you have gone about and blown my mind a second time. I never thought it would even be possible to take the most complicated concepts that humanity has ever known and explain it in such an accessible way. You're channel is going to blow up. You're the next Khan Academy
@@Mahesh_ShenoyI studied aerospace engineering where there is a lot of physics involved and was always very interested in it (almost studied physics). While I didn't learn something new, your videos are absolutely fantastic and you manage to convey and instill a more intuitive understanding of complex topics. Please keep this up! High school and college / university kids everywhere will benefit greatly from these. I don't know if you have done so yet, but you should consider translating these. Or perhaps offering a lesson pack with the illustrations, where the English text can be replaced. If you need someone to help with the German side, I'd be happy to help!
@@Mahesh_Shenoy I have some challenges to the idea that the speed of light is constant: The speed of light ISN'T the same in all frames! In the 1905 paper Einstein used Lorentz equations which is based on the one way speed of light NOT being C and he NEVER EVER claimed the one way speed of light is C. The idea that it is C was added later and it is impossible, there is no math to explain how the speed of light can be C in all directions! If you ask most people, most physicists they will say that length contraction and time dilation make the speed of light C, but this ONLY works for the 2 way speed of light because a slower clock will make light seem faster in both he direction of travel and against. Lorentz contraction can help make light moving in the same direction still be C because while your velocity subtracts from it, your clock being slower means fewer tick of the clock would occur, and your ruler being shortened by contraction of space means the light has less distance to go, this speeds up the light your travel has otherwise slowed down. But what for light moving the opposite direction? Here the light would be too fast, and then a slower clock will record less time again and a shorter distance makes it shorter again! Light would be super-duper-superluminal! But you object "You can't measure the one way speed of light" Well, you can, if SR (Special Relativity) is correct then the attempts to synchronize are moving at the same speed so the one way speed of light can be measured but would always be C. If however SR is wrong and say Lorentz Ether Theory (The theory that preceded SR, makes the same predictions and not one iota of evidence disagrees with or favours SR over LET) then then while the synchronization might be an issue in a given frame, as soon as you change frame the synchronization would be insufficient to make the one way speed of light seem the same in each direction! So you can distinguish between these theories (though the experiment might not have been done) and if LET is right then there is a preferred frame, there is an Ether and time dilation and length contraction are absolute and relative to your motion through the Ether. Also I can easily give you ways to measure the preferred frame or I can give you scenarios where SR produces fatal paradoxes it can't recover from. The idea there isn't a preferred frame that it couldn't be detected is nonsense.
It's actually a simple concept and can be derived easily through simple thought experiments. It's just that it appears so counterintuitive when you first learn it, that makes it so hard to comprehend.
I have not seen any teacher explaining complicated ideas in a super easy and simplified way like you Mahesh. Thank you for helping me to get a deep understanding of many topics.
I've sat here for well over an hour this morning watching and rewatching this video, and for the first time I feel like I'm actually beginning to gain a decent layman's understanding of the characteristics and vagaries of the behavior of light and electromagnetic radiation in general. I really appreciate the presentation, as my son and I (both adults) really enjoy discussing physics related subjects. As a curious layman I am thankful for the easily accessible style you provide. Well done.
Fantastic conversation with your son at a dinner table: Dad: Hey Son can you pass the salt? Son: Dad at a relativistic speed, I would not need to pass you the salt, you can grab it yourself due to length contraction!!! Dad: Wrong you are assuming we are travelling in opposite directions.
@@GMan958So I had another take on the dinner conversation: Dad: Hey son, can you pass the salt? Son: Sorry dad, but at relativistic speeds it will require near infinite levels of energy to boost your speed even in minute increments such that you might eventually hope to catch up to and pass the salt shaker given its much lower initial mass. Maybe go on a diet and we'll hope for better next time. Dad: Tell you what, son, maybe just hand me the sodium and chlorine and I'll work it out myself.
What an awesome video! Since high school I have not been able to capture or understand this intuition well, and 26 years later you have succeeded. Thanks so much. I think one of the MAIN reason students can't get the intuition is that any attempt to explain relativity starts with "person in a vehicle" vs the "person standing" metaphor. That is such a counterintuitive example. Human experience of a car or train or a plane is that of a transportation machine. They move in all of human experience. To put us in the shoes of the person inside the car, and then thinking that the person standing is the one actually moving, is extremely challenging and goes against our experience of world. I think educators should discard this example. The relative motion perspective that helped me is: Imagine two infinite escalators moving at constant velocity in opposite directions, next to each other (They don't wobble, or make sound, there are no walls, nothing to refer their motion). There is a person standing on each, and these persons have no way to tell if they are moving. Their experience is that of standing on an infinite stair. And then they cross each other. Person 1 perceives that Person 2 is moving, while Person 2 perceives that Person 1 is moving. Neither is able to tell if they are themselves moving. Surely not the best example, but to my simple mind this example helps me more than the person in a car metaphor.
I like to think of two astronauts floating in space and moving closer to each other. Each astronaut will perceive that they are stationary themselves, and it is the other astronaut that is moving closer. There is no objective way of telling who is stationary and who is moving.
I am not physicist, so i am not sure how well it translates to the topic, but according to relative movement, there is even better comparison. Limit your peripheral sight in a car standing in parking lot. Then observe a neigboring carto move. You are not able to tell if is moving second car, or your brakes failed and you are the one moving.
But in the car x person standing still example one of them is moving while the other is not.. despite the fact that they can't feel wich of them is actually moving. In your example both of them are moving.
Absolute mad respect!! I have been wondering about this for over 25yrs. Mugged up for exams, but could neither understand nor explain it. Looks like i finally understood why i always come across "inertial frame of reference " while reading this topic. You sire, have earned my respect today. 🎉
This was incredible. I really love it when educators walk us through the logic of HOW we arrived at our conclusions, including all the incorrect assumptions we made and discarded along the way. It really helps round out our understanding and motivation. This was really well made. Thanks so much
10/10 on enthusiasm, 10/10 on explanation. Honestly the best and most intuitive explanation of special relativity I have seen. Finally understood where time dilation comes from 😄 Thank you
So far I've watched three of your videos. First - why we can never travel at the speed of light, second - why does light have no mass, and third - this one, why is speed of light equal in all frames. And I can say that they are amazing. The method you present a problem by asking questions regarding the previously understood explanations until you arrive at the end, at what you're trying to ultimately explain, is just great and easy to follow for anyone.
😭 I almost cried from finally understanding this (and feeling stupid) after reading books and watching videos that weren’t helping me. Thank you SO much! Not only that, it was because of the way you explained how we intuitively thought everything moves, and even how we tested light based on these intuitions that I actually understood BEFORE the video ended. Right when you talked about how we could make light move faster, I thought, wait…time slows down and also distance contracts in the direction of travel! That’s it! That’s why light is STILL traveling the same speed!
The exciting dynamics you create when explains complicated stuff based on a supposed chat between you and Einstein, make things clear and so near to the audience that it feels that one can get in touch with you both. Became a big fan of your method for explaining difficult topics. Greetings.
Agreed. And it also shows the importance of coming up with a "maybe" then designing an experiment to establish the facts. Mahesh's style of explanation is superb.
So good. Thanks for taking the time and effort to produce this video. The clearest explanation for the layman I've seen yet, of how we arrived at an understanding of special relativity. And your enthusiasm for the subject is infectious!
You know what I've spent more than 10 years to understand relativity but I couldn't wrap my head around it until I watch your video. thanks very very much it was really useful!!
Wow. Just Wow. I've watched dozens of videos and read countless articles about relativity. I always just don't quite get it. This explanation is the best I've ever seen. I actually got to the end seeing what happens and not having to think, if you say so. Also your personalizing the presentation made it a little more fun!
I already know this stuff (as well as a layperson can), but having watched a couple of your videos now, your story-telling method of delivering the information and your infectious enthusiasm have given new life to these ideas! I wish I could offer more than just words of praise, but you are a great science communicator and I look forward to watching more and gaining new perspectives on things I thought I already knew!
I always thought that I had a pretty good grasp on special relativity, but your explanation of the complete history of this theory really deepened my understanding a lot more. Thank you, beautiful video.
This is great: clear, easy to digest and to use to explain again. Could you do time dilation vs length contraction as a follow up? In which proportion do the 2 effects happen?
Man you're a treasure. You've been the only person in my life ever that has been able to explain this so clear, so logical and perfectly making sense why the constant speed of light to all observers is the only possible way it could work.
I have watched hundreds, if not thousands of videos on the same topic. A lot of them were great but this one greatly simplified it. As I love teaching, I always think of how it can be explained simply and covering every part. You have made one of the best videos. Great.
It always blew my mind how Einstein - given the facts before him - was courageous enough to reach the logical conclusion that he did (that time can dilate and space can contract 🤯). And you took me though every step of 'his' thought process and logical deduction. It was beautiful.
Einstein himself said: "If you can't explain it simply, you don't understand it well enough." So, you obviously understand this very well. Thank you for presenting it in a digestible format.
@@Mahesh_Shenoy Relativity predicts moving inertial observers will see each others space contract and time dilate. This is a complete contradiction and shows that the effects of Relativity are not real. The only explanation is that it is an optical illusion! Also any theory based on it, like General Relativity, must also have the problem!
At 90% speed of light time passes about 50% slower. So the denominator should be 0,5... but you need to insert 0,1 for the observation to be correct? Or is it a combination of length contraction and time dilation like 50/0,5?
I love the imagined conversation style of your videos. The narrative brings out a more complete background and context for the theories making them even more fascinating.
That's called the Socratic method; that's how they used to teach in ancient Greece, but with their style, the teacher would ask guiding questions to the student, usually. It did go back and forth some.
Let me tell, this is the single best video on youtube right now, your explanation is something most professors do not even know about and i was looking for this explanation for over two moths now thank you so much!!
I watched dozens and dozens of videos trying to understand how could Einstein figure out the concept of special and general relativity. Now I finally get it, thank you!
Thank you for doing all this work. It always takes a lot of effort to understand what's happening in physics, and it's nice to have another person instead to make this effort from time to time.
glad I stumbled onto your channel. my answer is 'yes, please do a video on the derivative equations' also, if light is the constant and the others, length and time adjust, what happens if length is the constant? does that adjust light's speed and time in a different way?
Not only do you have an extraordinary ability to explain complex concepts in a readily digestible manner, but you make it fun. Dang. Currently binging my way through your content.
this is the first vid I saw of yours and I subbed instantly. Your capacity to teach and communicate complicated subjects simply is beyond anything else ive seen.
Knew every principle you talked about already (speed of light, time dilation, motion is relative) but never had it finally click until you explained it. Why C is the same for everyone, even if they are travelling at different speeds, I only now understand. Thank you
I discovered your channel only recently and I absolutely LOVE IT! I have been watching physics videos for years, and yes even read books (God forbid!), and I never came across clearer and more intuitive explanations that do not seem to underestimate (or overtax) my intelligence. It is very telling that, on several occasions while watching your videos, I have thought to myself "Wait a minute... what about this?"... and the next thing out of your mouth is something along the lines of "Wait a minute... what about this?", and you provide the answer. Absolutely stellar work! Many thanks and please keep this up!
Great video my man! I really liked how you took us on the journey of how Einstein came to his discoveries - it wasn't that it all just popped into his head in a single moment, it was a culmination of doing the maths again and again and thinking deeply about the real world scenarios
This video, which I came across by chance, is the only time I’ve come close to understanding this stuff so you have my immense thanks. I would greatly enjoy further videos like this. Thanks again.
Bro, I have never understood so intuitively the topic of relativity until coming across your channel, please keep doing what you are doing. THANKS for distributing knowledge
You are a genius. I have already watched many videos about these theories, but with you it is so simple and understandable. I thought I already understood it, but now I discover the true basis of these elements in a clear way without complicated formulas. thank you
This is easily one of the best videos i’ve ever watched, and the best explanation of anything related to physics. I genuinely feel ecstatic from finally understanding all this stuff, i love you
You can extend your medium analogy and consider that light travels in the "spacetime" medium, and the logic will still hold true. Because when spacetime itself bends or accelerates, it affects light in a similar manner as other waves are affected by their respective media in which they travel.
18:07 My freaking mind is blown sir,that was like the goosebumps scene in a great movie where u will get the title 20 minutes later.Seriously though I got goosebumps when u said “That is Time Dilation” It deserves a badass bgm for that point❤
I'm not a physicist or mathematician. I am an avid reader of science fiction since my youth in the 60s. I had a very rudimentary understanding of FTL and the problems of reaching it. I did not understand the concept of time dilation and light speed being a constant to every observer. Now I understand. Fully. Thank you.
@@froyocrew Why is he a pseud? Don't you agree that he's explained the theory of special theory albeit in a very simplified way, or do you not agree with the theory? I think he explained it very well, but then, I don't agree with the theory.
@gerontodon LOL you don't "agree" eh? Why not? Making Einsteins skin brown is disgusting too btw. I would never make a video about ghandi and make him a white guy
Unless you're Heisenberg. I don't remember who had the idea of uncertainty, but I think it was him. If not, then my point is that the only way you can beat Einstein is if you are uncertain about doing so
This channel could have 1 million subscribers and would still be underrated, it's just absurd how good it is (plus, extra points for the awesome accent!)
Bro, I appreciate your clarity and understanding of the Physics, but even more than that I appreciate your excitement about the concepts. It is something clearly visible and many including me share.
Wow. I have been searching for years how Einstein came to the conclusion that speed of light will be same in all reference frames. Your explanation makes perfect sense. Thank you for this great work. Keep doing more videos. Looking for intuitive explanation on mass energy equivalence.
Honestly, even though I already had a previous solid grasp on the concept, this was the best, most intuitive and intelligible content I've ever watched on it. I'll be sure to recommend it to friends, and I'm now a subscriber. Seriously, you're doing an amazing job.
I am a 66 year old Australian retired public servant with an interest in physics. Over the past few years I have gained some knowledge of the subject that you are speaking about. However until watching your video I did not have a true understanding of the topic. THANKYOU! AuziAli
Dude , you kinda earned a fan ... I watched this video to get the idea "how i can explain special relativity and time dilation to someone" and now i think i can explain it to a 12 years old too
sir, you are a big reason in my enthusiasm in physics.. never stop making these videos they are like therapy to me and it's crazy how simple and amazing things begin to look like when you explain them.💙
This is THE BEST video that I found on relativity. Till today, even though I watched a bunch of other videos, I never truly understood time dilation. But wow, what an explanation. Loved it❤
Commendable work Mahesh! Leading us, step by step, through your own thought progression as well as those of the inventor(s) in these simplified, easy to comprehend steps is quite ingenious! Why this method is not more widely used is a little baffling. Maybe because it requires some honesty and humility that is tragically lacking in academia? All the more respect to you Mahesh. Hopefully more will follow your lead going on. This has so many pedagogical benefits. One gets on board in the beginning and is allowed to logically reach each new step in sync with the narrative (and often just prior to the narrative which in turn gives a sense of accomplishment and pride and stronger desire to keep on learning). This is masterfully done Mahesh and shows that you are a true educator with the student's best interest in mind, rather than boasting about your own knowledge and intellect. Thank you for sharing your engaging approach and infectious curiosity 😁
I wish I had you as my physics teacher in high school. You explain it all so well. I still don't understand everything, but this particular topic is much clearer in my mind, now.
This video is amazing! I have taken special relativity and listened to many related videos but this is the first time i've ever understood why lights speed is constant, rather than just that it is.
Wow, in my 40's and that explained it better than anything I've ever seen. Thank you for describing how we got to this position of understanding in a way a 'normal' person can understand!
Thanks a lot for explaining it so simply, without any equations or complicated jargon. It's really clear now and I finally get the basic idea behind Relativity.
Extremely impressive. The conversation with Einstein was a nice touch. The "escalator effect" of a medium is a new one I hadn't heard before, but it's great. Sometimes I wonder if a very advanced civilization would say to us, "Light doesn't move, you and the particles that make you do."
Special relativity. One says, "You are moving. Your time is slow than mine." The counterpart says, "You are moving. Your time is slow than mine." Mathematically it is like both A>B and A
Excellent video. You break things down to make them understandable and deliver with enthusiasm that draws in the viewer until you bring them to that lightbulb moment YES! I see now I actually get it !!!!!!
I love your explanation! Building up step by step was so good for ultimately understanding wtf time dilation is and how it explains the speed of light stuff. Thank you for this!
Even after all this time of 9-5 work routine, I still deeply in love with the thought experiment of astrophysics! You really explained it in the way I did this thought provoking activity several years ago! Just wow!
So good!!
OMG OMG OMG OMG OMG OMG OMG OMG OMG OMG! Is it really you?
@@Mahesh_Shenoyyeah, I'm shocked too
Please tell us referen materials?
How did you come here lol
They have tricked you into slavery by false heroes 👉 The Connections (2021) [short documentary] 💖
Never met a guy that had so much conversations with Einstein. And than sharing it with us even. Thanks Mahesh!
Guy must be immortal. He sometimes tells us about his conversations with Newton.
@@sleepycritical6950lmaoo😭😭
And Moses said "Mahesh, give it a rest!"
Einstein was once asked why he was not able to finish his grand theory of everything. He replied there was this Indian guy calling him every other day.
@@ThirstyGreen 😂😂😂 that must be it!!
Did not understand this as an undergrad over a half-century ago. Went on to get PhD in math a few years later and had a 45-year career as a math professor, never really understanding this.... And now? This presentation was Magnificent! Thank you so much! OH, AND YES! PLEASE DO SHOW THE ALGEBRA/ GEOMETRY IN A FUTURE VIDEO!
Thank you for giving me some hope
And that’s the problem with our education system 😂😂❤
Still doesn't really explain it. Just gives a new prohibition "no test exists to determine what reference frame is moving at constant velocity." Which is less intuitive than the simple fact light moves at the same speed regardless of reference frame velocity. Why is it impossible to know and why is light a fixed speed limit.
We need to get this guy to 1m subs. I watch a ton of science communication channels, all the heavy hitters, and this guy far and away does the best job of walking through these problems in an intuitive way.
As a teacher, I always find it difficult to simplify the topic . But once I could prepare the topic like you did in the video, my job becomes easier.
They have tricked you into slavery by false heroes 👉 The Connections (2021) [short documentary] 💖
@@VeganSemihCyprus33Guy no.
Shame that Einsteins hypothesis is totally wrong. I mean it has unrecoverable errors that make the theory impossible nonsense. No one cares enough to discuss what the problems are. They are happy to believe the irrational.
though much simpler explanation is that speed of light is not about light but about causality, and since light is a gauge boson, carrier of e/m interaction (i.e. causality), and since interaction defines time itself - it's by definition that speed (which is derived from time) of light is the same in all inertial frames of reference
@@z08840 The speed of light is the speed of light. "Causality" is an abstract idea, not something that you can measure how fast its moving. Stop mixing up fantasy concepts with real Physics. There is no such thing as a gauge boson, that is also an idea. And a silly one at that. The measure of light speed is NOT the same in all frames of reference, that fantasy is irrational.
I watched dozens of videos about relativity and this was by FAR the best. Please make more exactly like this
BY FAR!! So good.
Agree, hes done a good job. + the expression and enthusiasm.
When I was younger, the example at 15:25 boggled my mind, thinking that the speed of a spaceship and the light emitted from the spaceship's headlights would add up, and should be faster than the speed of light. LOL Silly me, now we know that the speed of light appears to be the same for all observers, both on the ship and the outside.
I agree. All the "yes, but..." questions I've had previously were answered one by one.
Evidences for Varying Speed of Light with TimeGiuseppe Pipino
Technical High School, ITIS Malignani, Udine, Italy.
DOI: 10.4236/jhepgc.2019.52022 PDF HTML XML 836 Downloads 3,392 Views Citations
Abstract
Aims: The paper explores the hypothesis that the speed of light c is decreasing over time at rate (dc/dt)=-H⋅ c, H being the Hubble constant. This hypothesis differs from the so-called tired light, in which the velocity c is supposed to vary during the journey of photons in the empty space for some frictional mechanism. In the hypothesis of the author the speed c, during this journey, is assumed constant. In this way the problems of the tired hypothesis are overcome. Methods: The paper links the variation dc/dt with the Hubble constant and infers a value of dc/dt from the difference between the value of the variation of the Earth-Moon distance measured by the Lunar Laser Ranging Experiment and the tidal effect. Results: Under the hypothesis c time varying, we explain: 1) The cosmological redshift. 2) The anomalous acceleration ap ≈ -8 × 10-10 m⋅sec-2, measured for some spacecrafts. 3) The high redshift of supernovae Ia, which seems to evidence an acceleration of the expansion of the universe. 4) The peripheral motion of stars in galaxies around their rotational centre. 5) The dilation of the light curves observed for supernovae Ia.
Nobody's ever explained that better than this, science needs more people like you, my friend.
This is why Einstein said "Imagination is more important than knowledge". I'm proud of myself!! 🤓Today, for the first time in my life, I imagined outcomes of special theory of relativity. Thanks Mahesh. Please do the next part of the video.
Awesome! Will do!
That's amazing @brijeshpatel5017 and I thank you for sharing. This is great content for anyone ready to step out of their own perspective.
Because he was not a scientist and did not perform the scientific method.
@@wesbaumguardner8829He was and he did. Saying the opposite doesnt make it true.
@@tlpineapple1 What experiments did he perform utilizing the scientific method? Simply stating he was a scientist does not make it true.
“Your honor, I was at rest, the schoolchildren were coming at me at 80 mph.”
This needs more likes😂
😂
lol that made me laugh so hard that's amazing.
If I were the judge, I would have countered your argument at first instance by telling you that the question is not about who was in motion but who caused that motion to happen. So It was you who caused the motion of your surrounding. 😀
@@bhanukhandelwal8033You should rewatch the video!
indians helping random youtubers is stepping up from voice and notepad text tutorials to this masterpiece. sir u answered the questions i had been looking for in such an elegant way i salute you
To teach experts, one only needs notepad , to teach a layman one needs animation but it's not niche enough anymore.
Space time is a medium
@@Brianboru-k8y it is not a medium, if it is a medium what is this medium made of ? a medium is a field of material/matter what waves propagate in spacetime is not that
You are the only person who has ever explained this in a way that actually makes sense to me. TY
This is the best explanation I have ever seen. Simplified and crystal clear.
I think what makes this so hard is that we have adopted the phrase “speed of light” for c. If we'd called it the “speed of causation” and then said _it turns out_ that in the absence of a medium, light moves at the speed of causation, it would be much easier to wrap your head around. Indeed, it also opens the door for the (it turns out) meaningful question of _why_ light should travel at this speed-because light does in fact have relevant properties that other phenomena don't. But “why does light travel at the speed of light?” invites no such exploration.
As a biology PhD who is trying to learn more physics, I felt mind blown by your derivation! Keep it up!
Nice!
GL on your journey. What have you learned so far?
Maybe there is still hope for you? 😂
@@Bjowolf2 huh?
@@y.o.2478 A reply to the biologist at the top of the thread, who is now taking an interest in physics incl. relativity theory - impressive 😉
As a historian with an interest in science, your videos are great. Thank you for the top notch content
One of the best physics communicators on UA-cam!
I never really truly grasp the true meaning of the special relativity, until i watched your video. Your style of teaching is really intuitive and easy to follow, even on complex topics. Love your work, and keep doing what you're doing, cheers.
I have never understood more about special relativity than I do now after watching your video. You are hands down the best science teacher I have ever seen. And I subscribe to every science channel on UA-cam. The first time you blew my mind was your explanation of angular momentum and electron spin. Now you have gone about and blown my mind a second time. I never thought it would even be possible to take the most complicated concepts that humanity has ever known and explain it in such an accessible way. You're channel is going to blow up. You're the next Khan Academy
Oh man, this made my day!!!!! Thank you.
@@Mahesh_ShenoyI studied aerospace engineering where there is a lot of physics involved and was always very interested in it (almost studied physics). While I didn't learn something new, your videos are absolutely fantastic and you manage to convey and instill a more intuitive understanding of complex topics. Please keep this up! High school and college / university kids everywhere will benefit greatly from these. I don't know if you have done so yet, but you should consider translating these. Or perhaps offering a lesson pack with the illustrations, where the English text can be replaced. If you need someone to help with the German side, I'd be happy to help!
@@Mahesh_Shenoy I have some challenges to the idea that the speed of light is constant: The speed of light ISN'T the same in all frames! In the 1905 paper Einstein used Lorentz equations which is based on the one way speed of light NOT being C and he NEVER EVER claimed the one way speed of light is C. The idea that it is C was added later and it is impossible, there is no math to explain how the speed of light can be C in all directions! If you ask most people, most physicists they will say that length contraction and time dilation make the speed of light C, but this ONLY works for the 2 way speed of light because a slower clock will make light seem faster in both he direction of travel and against. Lorentz contraction can help make light moving in the same direction still be C because while your velocity subtracts from it, your clock being slower means fewer tick of the clock would occur, and your ruler being shortened by contraction of space means the light has less distance to go, this speeds up the light your travel has otherwise slowed down. But what for light moving the opposite direction? Here the light would be too fast, and then a slower clock will record less time again and a shorter distance makes it shorter again! Light would be super-duper-superluminal! But you object "You can't measure the one way speed of light" Well, you can, if SR (Special Relativity) is correct then the attempts to synchronize are moving at the same speed so the one way speed of light can be measured but would always be C. If however SR is wrong and say Lorentz Ether Theory (The theory that preceded SR, makes the same predictions and not one iota of evidence disagrees with or favours SR over LET) then then while the synchronization might be an issue in a given frame, as soon as you change frame the synchronization would be insufficient to make the one way speed of light seem the same in each direction! So you can distinguish between these theories (though the experiment might not have been done) and if LET is right then there is a preferred frame, there is an Ether and time dilation and length contraction are absolute and relative to your motion through the Ether. Also I can easily give you ways to measure the preferred frame or I can give you scenarios where SR produces fatal paradoxes it can't recover from. The idea there isn't a preferred frame that it couldn't be detected is nonsense.
It's actually a simple concept and can be derived easily through simple thought experiments. It's just that it appears so counterintuitive when you first learn it, that makes it so hard to comprehend.
I have not seen any teacher explaining complicated ideas in a super easy and simplified way like you Mahesh. Thank you for helping me to get a deep understanding of many topics.
I've sat here for well over an hour this morning watching and rewatching this video, and for the first time I feel like I'm actually beginning to gain a decent layman's understanding of the characteristics and vagaries of the behavior of light and electromagnetic radiation in general. I really appreciate the presentation, as my son and I (both adults) really enjoy discussing physics related subjects. As a curious layman I am thankful for the easily accessible style you provide. Well done.
Fantastic conversation with your son at a dinner table:
Dad: Hey Son can you pass the salt?
Son: Dad at a relativistic speed, I would not need to pass you the salt, you can grab it yourself due to length contraction!!!
Dad: Wrong you are assuming we are travelling in opposite directions.
@@GMan958 Nice! Merry Christmas and joyous holiday happenings all around!
Thanks!!!
@@GMan958So I had another take on the dinner conversation:
Dad: Hey son, can you pass the salt?
Son: Sorry dad, but at relativistic speeds it will require near infinite levels of energy to boost your speed even in minute increments such that you might eventually hope to catch up to and pass the salt shaker given its much lower initial mass. Maybe go on a diet and we'll hope for better next time.
Dad: Tell you what, son, maybe just hand me the sodium and chlorine and I'll work it out myself.
What an awesome video! Since high school I have not been able to capture or understand this intuition well, and 26 years later you have succeeded. Thanks so much.
I think one of the MAIN reason students can't get the intuition is that any attempt to explain relativity starts with "person in a vehicle" vs the "person standing" metaphor. That is such a counterintuitive example. Human experience of a car or train or a plane is that of a transportation machine. They move in all of human experience. To put us in the shoes of the person inside the car, and then thinking that the person standing is the one actually moving, is extremely challenging and goes against our experience of world.
I think educators should discard this example. The relative motion perspective that helped me is: Imagine two infinite escalators moving at constant velocity in opposite directions, next to each other (They don't wobble, or make sound, there are no walls, nothing to refer their motion). There is a person standing on each, and these persons have no way to tell if they are moving. Their experience is that of standing on an infinite stair. And then they cross each other. Person 1 perceives that Person 2 is moving, while Person 2 perceives that Person 1 is moving. Neither is able to tell if they are themselves moving.
Surely not the best example, but to my simple mind this example helps me more than the person in a car metaphor.
I like to think of two astronauts floating in space and moving closer to each other. Each astronaut will perceive that they are stationary themselves, and it is the other astronaut that is moving closer. There is no objective way of telling who is stationary and who is moving.
Thank you,
I am not physicist, so i am not sure how well it translates to the topic, but according to relative movement, there is even better comparison. Limit your peripheral sight in a car standing in parking lot. Then observe a neigboring carto move. You are not able to tell if is moving second car, or your brakes failed and you are the one moving.
But in the car x person standing still example one of them is moving while the other is not.. despite the fact that they can't feel wich of them is actually moving.
In your example both of them are moving.
You are in a stationary train and see another stationary train in the window. Have you ever wondered which of them suddenly begins to move?
I don’t remember how I found you but this is quickly becoming one of my favorite channels
Absolute mad respect!! I have been wondering about this for over 25yrs. Mugged up for exams, but could neither understand nor explain it. Looks like i finally understood why i always come across "inertial frame of reference " while reading this topic. You sire, have earned my respect today. 🎉
This was incredible. I really love it when educators walk us through the logic of HOW we arrived at our conclusions, including all the incorrect assumptions we made and discarded along the way. It really helps round out our understanding and motivation. This was really well made. Thanks so much
10/10 on enthusiasm, 10/10 on explanation. Honestly the best and most intuitive explanation of special relativity I have seen. Finally understood where time dilation comes from 😄 Thank you
So far I've watched three of your videos. First - why we can never travel at the speed of light, second - why does light have no mass, and third - this one, why is speed of light equal in all frames. And I can say that they are amazing. The method you present a problem by asking questions regarding the previously understood explanations until you arrive at the end, at what you're trying to ultimately explain, is just great and easy to follow for anyone.
😭 I almost cried from finally understanding this (and feeling stupid) after reading books and watching videos that weren’t helping me. Thank you SO much! Not only that, it was because of the way you explained how we intuitively thought everything moves, and even how we tested light based on these intuitions that I actually understood BEFORE the video ended. Right when you talked about how we could make light move faster, I thought, wait…time slows down and also distance contracts in the direction of travel! That’s it! That’s why light is STILL traveling the same speed!
The exciting dynamics you create when explains complicated stuff based on a supposed chat between you and Einstein, make things clear and so near to the audience that it feels that one can get in touch with you both. Became a big fan of your method for explaining difficult topics. Greetings.
Agreed. And it also shows the importance of coming up with a "maybe" then designing an experiment to establish the facts. Mahesh's style of explanation is superb.
Socratic style
@@NishanthSalahudeen I was about to say this LOL!
So good. Thanks for taking the time and effort to produce this video. The clearest explanation for the layman I've seen yet, of how we arrived at an understanding of special relativity. And your enthusiasm for the subject is infectious!
You know what I've spent more than 10 years to understand relativity but I couldn't wrap my head around it until I watch your video. thanks very very much it was really useful!!
Wow. Just Wow.
I've watched dozens of videos and read countless articles about relativity. I always just don't quite get it.
This explanation is the best I've ever seen. I actually got to the end seeing what happens and not having to think, if you say so.
Also your personalizing the presentation made it a little more fun!
I already know this stuff (as well as a layperson can), but having watched a couple of your videos now, your story-telling method of delivering the information and your infectious enthusiasm have given new life to these ideas! I wish I could offer more than just words of praise, but you are a great science communicator and I look forward to watching more and gaining new perspectives on things I thought I already knew!
I always thought that I had a pretty good grasp on special relativity, but your explanation of the complete history of this theory really deepened my understanding a lot more. Thank you, beautiful video.
This is great: clear, easy to digest and to use to explain again. Could you do time dilation vs length contraction as a follow up? In which proportion do the 2 effects happen?
They're pretty much the same thing. You just use the one that has to do with what you are trying to figure out.
When I tried to teach my kids math when they were young, I always made them cry. I wish I could harness the joy you share in these videos!
Me too 😣
Mostly cos you talked about taking apples away from them.
Man you're a treasure. You've been the only person in my life ever that has been able to explain this so clear, so logical and perfectly making sense why the constant speed of light to all observers is the only possible way it could work.
I have watched hundreds, if not thousands of videos on the same topic. A lot of them were great but this one greatly simplified it.
As I love teaching, I always think of how it can be explained simply and covering every part.
You have made one of the best videos.
Great.
Beautiful video! As a TA for a class that introduces time dilation, I haven’t seen an explanation as clear (and enthusiastic!) as this one. Great job.
BY FAR the bestest one all over UA-cam. Thank you very much Mahesh for such wondrous explanation.
It always blew my mind how Einstein - given the facts before him - was courageous enough to reach the logical conclusion that he did (that time can dilate and space can contract 🤯).
And you took me though every step of 'his' thought process and logical deduction. It was beautiful.
Neither time nor space have any properties so how could they dilate or contract?
Wow, great job simplifying the ideas and you bring excited, compelling energy in your presentation. Don’t stop teaching!
Thanks a lot. Won't!
Einstein himself said: "If you can't explain it simply, you don't understand it well enough." So, you obviously understand this very well. Thank you for presenting it in a digestible format.
Brilliant explanation for an extremely delicate subject 👍🏼
Thanks :)
@@Mahesh_Shenoy Relativity predicts moving inertial observers will see each others space contract and time dilate. This is a complete contradiction and shows that the effects of Relativity are not real. The only explanation is that it is an optical illusion! Also any theory based on it, like General Relativity, must also have the problem!
At 90% speed of light time passes about 50% slower. So the denominator should be 0,5... but you need to insert 0,1 for the observation to be correct? Or is it a combination of length contraction and time dilation like 50/0,5?
@@williamwalker39agree with you.. there’s something missing here.. the reciprocal nature of the dilations/contractions is still unexplained
I love the imagined conversation style of your videos. The narrative brings out a more complete background and context for the theories making them even more fascinating.
That's called the Socratic method; that's how they used to teach in ancient Greece, but with their style, the teacher would ask guiding questions to the student, usually. It did go back and forth some.
This is a gem. I think you may just be the best science communicator of all time. I never got to understand relatively so well.
Let me tell, this is the single best video on youtube right now, your explanation is something most professors do not even know about and i was looking for this explanation for over two moths now thank you so much!!
Did the two moths ever answer you? :)
Over two moths! I thought one was bad enough.🙃How many moths until you finally got it?
I couldn't understand the "forbidden" part. Why is it "forbidden" to detect uniform from rest, but not "forbidden" to dilate time?
Your insight, presentation style, and energy are fantastic. I'm excited to see what you put out next!
Thanks, buddy! :)
I watched dozens and dozens of videos trying to understand how could Einstein figure out the concept of special and general relativity. Now I finally get it, thank you!
Thank you for doing all this work. It always takes a lot of effort to understand what's happening in physics, and it's nice to have another person instead to make this effort from time to time.
Your explanation was so good that time dilation occurred to me in the instant before you revealed it. You are a supremely gifted teacher. Subscribed!
Finally I fond the best explanation for time dilation and length contraction. ❤
Thank you very much.
glad I stumbled onto your channel. my answer is 'yes, please do a video on the derivative equations'
also, if light is the constant and the others, length and time adjust, what happens if length is the constant? does that adjust light's speed and time in a different way?
What a wonderful explanation! I love your presentation! You are clear and concise, making these concepts accessible and understandable.
Not only do you have an extraordinary ability to explain complex concepts in a readily digestible manner, but you make it fun. Dang. Currently binging my way through your content.
this is the first vid I saw of yours and I subbed instantly. Your capacity to teach and communicate complicated subjects simply is beyond anything else ive seen.
Thanks a lot. And welcome! :)
Knew every principle you talked about already (speed of light, time dilation, motion is relative) but never had it finally click until you explained it.
Why C is the same for everyone, even if they are travelling at different speeds, I only now understand. Thank you
I discovered your channel only recently and I absolutely LOVE IT! I have been watching physics videos for years, and yes even read books (God forbid!), and I never came across clearer and more intuitive explanations that do not seem to underestimate (or overtax) my intelligence. It is very telling that, on several occasions while watching your videos, I have thought to myself "Wait a minute... what about this?"... and the next thing out of your mouth is something along the lines of "Wait a minute... what about this?", and you provide the answer. Absolutely stellar work! Many thanks and please keep this up!
Great video my man! I really liked how you took us on the journey of how Einstein came to his discoveries - it wasn't that it all just popped into his head in a single moment, it was a culmination of doing the maths again and again and thinking deeply about the real world scenarios
This video, which I came across by chance, is the only time I’ve come close to understanding this stuff so you have my immense thanks. I would greatly enjoy further videos like this. Thanks again.
Bro, I have never understood so intuitively the topic of relativity until coming across your channel, please keep doing what you are doing. THANKS for distributing knowledge
You are a genius. I have already watched many videos about these theories, but with you it is so simple and understandable. I thought I already understood it, but now I discover the true basis of these elements in a clear way without complicated formulas. thank you
You are a phenomenal teacher!! I can't wait to see what you put out next :)
Thanks :)
This is easily one of the best videos i’ve ever watched, and the best explanation of anything related to physics. I genuinely feel ecstatic from finally understanding all this stuff, i love you
You can extend your medium analogy and consider that light travels in the "spacetime" medium, and the logic will still hold true. Because when spacetime itself bends or accelerates, it affects light in a similar manner as other waves are affected by their respective media in which they travel.
18:07 My freaking mind is blown sir,that was like the goosebumps scene in a great movie where u will get the title 20 minutes later.Seriously though I got goosebumps when u said “That is Time Dilation” It deserves a badass bgm for that point❤
Wow! That was the planned epic moment. I am so glad, it resonated with you! Thanks for letting me know. 🚀
i think it's amazing that you as a bigger content creator is giving a platform to an aspiring physicist like einstein 🙏🏾
First view.thank you for your videos. Please continue this series please cover all topics like this sir
Absolutely!!
7:09 Excuse me, what about doppler shift, a well known phenomenon in EM?
Doppler shift affects the wavelength and frequency of light, not the speed.
I'm not a physicist or mathematician. I am an avid reader of science fiction since my youth in the 60s. I had a very rudimentary understanding of FTL and the problems of reaching it. I did not understand the concept of time dilation and light speed being a constant to every observer. Now I understand. Fully. Thank you.
"here's Einstein in an open car coming towards me" - yes you clearly can identify him by HIS HAIR 😁😁😁
and his brown skin too according to the pseud who made the video
@@froyocrew
Why is he a pseud? Don't you agree that he's explained the theory of special theory albeit in a very simplified way, or do you not agree with the theory? I think he explained it very well, but then, I don't agree with the theory.
@gerontodon LOL you don't "agree" eh? Why not?
Making Einsteins skin brown is disgusting too btw. I would never make a video about ghandi and make him a white guy
Moral of the story: You cannot win against Einstein!!!
Unless you're Heisenberg. I don't remember who had the idea of uncertainty, but I think it was him. If not, then my point is that the only way you can beat Einstein is if you are uncertain about doing so
Omg what a channel. This is what UA-cam is for! If only we had teachers like you at school.. Thanks a ton for your work!!
First Comment 😂😂
You rock
So many years of knowing this but not really knowing it. Blown away. Thank you!
This channel could have 1 million subscribers and would still be underrated, it's just absurd how good it is (plus, extra points for the awesome accent!)
Bro, I appreciate your clarity and understanding of the Physics, but even more than that I appreciate your excitement about the concepts. It is something clearly visible and many including me share.
I’ve had this explained to me a hundred times, but only after watching your video did it “click”! Thank You!
Wow. I have been searching for years how Einstein came to the conclusion that speed of light will be same in all reference frames. Your explanation makes perfect sense. Thank you for this great work.
Keep doing more videos. Looking for intuitive explanation on mass energy equivalence.
Honestly, even though I already had a previous solid grasp on the concept, this was the best, most intuitive and intelligible content I've ever watched on it. I'll be sure to recommend it to friends, and I'm now a subscriber. Seriously, you're doing an amazing job.
I am a 66 year old Australian retired public servant with an interest in physics.
Over the past few years I have gained some knowledge of the subject that you are speaking about. However until watching your video I did not have a true understanding of the topic.
THANKYOU!
AuziAli
Dude , you kinda earned a fan ... I watched this video to get the idea "how i can explain special relativity and time dilation to someone" and now i think i can explain it to a 12 years old too
I have over time began to follow many indians, just by chance and algorithms. It had served me well.
Good job om this one.
The best description of special relativity I've seen - Thank you Mahesh!
sir, you are a big reason in my enthusiasm in physics.. never stop making these videos they are like therapy to me and it's crazy how simple and amazing things begin to look like when you explain them.💙
This is THE BEST video that I found on relativity. Till today, even though I watched a bunch of other videos, I never truly understood time dilation. But wow, what an explanation. Loved it❤
I cant believe i just now understood this after watching dozens of videos on this topic. Amazing video!
Commendable work Mahesh! Leading us, step by step, through your own thought progression as well as those of the inventor(s) in these simplified, easy to comprehend steps is quite ingenious!
Why this method is not more widely used is a little baffling. Maybe because it requires some honesty and humility that is tragically lacking in academia? All the more respect to you Mahesh. Hopefully more will follow your lead going on.
This has so many pedagogical benefits. One gets on board in the beginning and is allowed to logically reach each new step in sync with the narrative (and often just prior to the narrative which in turn gives a sense of accomplishment and pride and stronger desire to keep on learning). This is masterfully done Mahesh and shows that you are a true educator with the student's best interest in mind, rather than boasting about your own knowledge and intellect.
Thank you for sharing your engaging approach and infectious curiosity 😁
I wish I had you as my physics teacher in high school. You explain it all so well. I still don't understand everything, but this particular topic is much clearer in my mind, now.
This video is amazing! I have taken special relativity and listened to many related videos but this is the first time i've ever understood why lights speed is constant, rather than just that it is.
Wow, in my 40's and that explained it better than anything I've ever seen. Thank you for describing how we got to this position of understanding in a way a 'normal' person can understand!
Thanks a lot for explaining it so simply, without any equations or complicated jargon. It's really clear now and I finally get the basic idea behind Relativity.
Dude, I had goosebumps when you got to Time Dilation! Mind blown! Amazing video... Great explanation and communication skills!
Extremely impressive. The conversation with Einstein was a nice touch. The "escalator effect" of a medium is a new one I hadn't heard before, but it's great. Sometimes I wonder if a very advanced civilization would say to us, "Light doesn't move, you and the particles that make you do."
first time, after dozens of trials, that I really understand where special relativity comes from. I love the way you present it, very intuitive.
Special relativity. One says, "You are moving. Your time is slow than mine." The counterpart says, "You are moving. Your time is slow than mine." Mathematically it is like both A>B and A
The best explanation I've seen for time dilation in special relativity. Thanks, Mahesh.
Excellent video. You break things down to make them understandable and deliver with enthusiasm that draws in the viewer until you bring them to that lightbulb moment YES! I see now I actually get it !!!!!!
I love your explanation! Building up step by step was so good for ultimately understanding wtf time dilation is and how it explains the speed of light stuff. Thank you for this!
Excellent! It's the most educational video on the reasoning behind special relativity that I have ever seen.
Even after all this time of 9-5 work routine, I still deeply in love with the thought experiment of astrophysics! You really explained it in the way I did this thought provoking activity several years ago! Just wow!