I heard you folks! What do we see from the ship’s perspective? Here you go - ua-cam.com/video/6wXwfcFYKLE/v-deo.html Hint: We discover the second consequence of special relativity. (one more to go)
Yeah, this explanation that you give requires the establishment of an absolute reference frame. If we can do that, then time dilation and length contraction are real phenomena. Otherwise, if we can't define an absolute reference frame, and spacetime really is absolutely relative - then time dilation and length contraction are NOT real phenomena, but simply visual illusions like the ones we get when we put a spoon inside a glass of water... The spoon doesn't change shape... So yes, a lot can be said about this, and honestly, I don't think that a full explanation really exist. Not even Einstein was sure what to make of all that. As for someone who has read his actual books, along his life, he was constantly changing his mind about if an absolute reference frame really exists or not...
I guess you won't notice the dilation from inside the ship, since it affects you as well, ship keeps accelerating at a constant rate, getting you to Lightspeed eventually. But you might arrive a couple of million years late at your destination. Ooops
@Mahesh_Shenoy I think that you are trying to say that the speed of an object is an inherent attribute of that object - and its not. For example, a neutrino - ISNT traveling close to the speed of light. Its only traveling close to the speed of light RELATIVE to us here on Earth. There should exist, at least 1 observer out in the Universe that measures the speed of that same neutrino and finds it to be equal to that of a bike... So what is it? Is the neutrino traveling close to the speed of light or the speed of a bike? Neither. The ONLY way to know the speed of a neutrino is if we had a global refference frame, which is absolute, and then yes - then we would be able to assign "close to lightspeed" as an inherent ATTRIBUTE to that netutrino. We will know for sure its exact speed relative to that 1 absolute frame. So to ask "Why can't something travel at the speed of light" is a question that implies - that we can somehow measure the exact speed of an object... Which in turn implies that there is a global refference frame that will give us that knowledge. Neither of these are shown to be true; The speed of light being a speed limit CANT be explained using relativity - because its an AXIOM of relativity.
Well, it's fine, but it's basically theoretical. We currently have a very surface level understanding of the universe and its physics. We know the results but not really the underlying structure that determines the results. It's like understanding a car's functions, what it can and can't do, but having no knowledge of the engine, drive train, suspension, cooling. You only see the results and don't actually understand how the car works. So you keep pushing to see if the car can, in fact, do things it's not supposed to be able to and accept the results even though your lack of understanding of the components that make up the car could be the reason you are getting the results and not that your results are definitive.
After 38 years finally someone came along to explain this phenomenon in an intuitive and understandable way. Thank you for finally making me understand what is going on! 🙏
Well one thing always ruins the logic. He said the clocks time is affected when in motion. Motion however is relative, so you, observing the clock, are also moving sideways relative to the clock. So how does the universe decide which time frame slows in relation to the other? They cant both slow down.
@@Zach-mi6tobecause there is no universal frame of reference. This is all relative to something, a clock at rest compared to the moving object (relative to the resting clock). There is no universal frame or clock. Everything is relative to whatever resting object you measure from. In essence: you need to unthink the universal frame of the universe that feels intuitive. It doesn't exist.
@@BooleanDisorder u r missing your own point. There's no such thing as a "resting" reference point. There is no resting clock, bc as u mention, there's no universal reference. That's my point.
@@BooleanDisorder with acceleration yes, it then becomes an asymmetrical equation and dilates time just like a gravitational field. But two objects in uniform relative motion, for both to experience a slowing of time would suggest they are each creating a new version of reality. Or something like that. Doesn't make sense but maybe there's a consensus answer somewhere.
Hi Mahesh!! Can you make a video about Cherenkov radiation? Why does a charged particle emit electromagnetic radiation when it is traveling through a medium at a speed greater than that of light through the medium? @@Mahesh_Shenoy
They say there is always an Indian guy on UA-cam with a tutorial for any topic. Now an Indian guy made the best tutorial for relativity. I guess we can see "how to build a time machine" tutorial soon from some Indian guy. Amazing job.
2 місяці тому+5
Hey , how is the war economy going on in Russia? Regards from India🇮🇳👳🏻♂️
Sorry to hear that man. I dropped out of school due to the side effects of a nasty head injury that also left a ceramic plate on the left side of my head. But despite teachers thinking that I was just one step away from being labeled as "Mentally Challenged", I still managed to independently discover the special relativity(SR) phenomena, derive the SR mathematical equations, along with independently deriving the Lorentz transformation equations, and the method that I used to derive these equations has not even been thought of by others as of yet.
This thread cracks me up. A self deprecating post by a confident person and a bunch of low self esteem jackasses piling on. "Sorry you not smart. Me understand everything because ceramic brain." It's pretty hilarious to me.
Wow. I have read countless Quora posts/comments, watched many YT vids, read science mags, articles, etc. and this FINALLY explained it to me. Only took like 40 years! Thanks so much for what you do.
I've read the same concept in two different text books for hours... But this man gave me the complete intuition in just 16 minutes... Hats off to your work sir...
Everybody who makes physics videos talk about time dilation and special relativity.. but no one explained it as intuitively and as simply as you did, I have stumbled upon time dilation equation many times and never seemed to understand where it came from... But now I can perfectly see it and make sense of it, keep up this beautiful work and I am deeply grateful for your efforts
I believe that’s because they don’t understand it either. They just regurgitate information. If one can break down information to an intuitive level then one has truly understood it.
My man. This was one of the most joyous videos I’ve ever watched on physics. Your joy is contagious and I love every second of it. Love the way you explain everything and your emotion behind it all.
I’m 52 and have a college degree (granted in history) and am also a big sci fi guy. This is the first explanation I’ve heard that actually made sense, even in physics classes. Thank you.
Despite the rude jabs here..."Oh the Humanities!"....your statement is very common in our population. Many people highly educated or stopping at HS are highly specialized in education today. There are far fewer hard sciences students than non empirical students in most of society. However there are a great number of Sci Fi fans that have picked up science sounding terms but applied by fantasy writers as a vague technobabble. I (physical chemist) run into a lot of people that insist they understand and are experts on some material theory or another (astrophysics, medicine, chemistry, biology, geology, etc...). Yet in casual conversation I can often find out exactly where they picked up the idea. I'm sure you find the same is true when you meet someone that learned history at the box office. History is a fine and honorable degree and profession.
This was the best explanation ever. You’ve asked the same questions I had, a real clock and now I understand why we simplify it. Thank you for this in depth answer. My physics professor just keeps saying well you can’t travel at the speed of light, you just can’t, doesn’t provide an answer. Now finally I understand why time dilation matters. ❤
And because of time dilation combined with dividing by 0 to unleash the power of quantum effects, the light barrier can be broken, all we need is to make such machine that can divide by 0, a computer high-tech enough to program such machine, and fuel potent enough to allow the machine to use quantum effects. As long as we break away, everything becomes possible.
2 AP classes in high-school, and 4 years of high level mathematics in college, but the random guy I find on youtube explains this better than any teacher or professor I've ever had.
ahh! For years, now I have gotten the video which almost explains me why can't we reach the speed of light. Great one. And the best part is you are more excited to explain it.
With no exaggeration, this man and his videos should be in every high school and college classroom. I've struggled with this topic for years and in two 15-20 minute videos, he clearly and concisely explains time and distance dilation in a way that someone like me, with a great interest in astronomy/physics/special relativity but who does not possess a degree in these areas, can understand. Furthermore, the way he unfolds the narrative, like a building conversation with Einstein and with his contagious excitement of the topic and of finally understanding it sprinkled in, completely amplifies the greatness here. Well done! You've earned a life-long subscriber.
@@royfeigel2535 What this video does is explain time dilation in a way that can be easily understood. I now grasp the concept. I do not understand it, but If I were to learn the details I would be able to link the equations with my understanding of the concept to fully grasp it
I love how you are asking common senses questions (and answering them). Questions most of us can't get answered by physicists because they are incapable of stepping out of their wrote explanations. Great job.
This is literally the best illustration of special relativity and time dialation. I don't think anyone has explained it better. Thank you for making it so clear.
No other video on this topic has explained it as well as you have. I suddenly am able to comprehend time dilation and why it actually happens. You are an awesome teacher!
Absolutely adore your excitement and the love that you put into the content you produce. Never understood time dilation until now, and your joy from physics is contagious :) Please continue with such a high quality content! :D
Why isn't your channel way more popular!? Holy crap. I literally understood everything... 🤯🤯 your video also clarified a lot of things "explained" by other videos and other people and other writings.
This is the best science communication channel I have ever found. Your excitement while explaining is contagious. I really enjoy the passion with which you teach. You truly love what you do. Your teaching style and verbal fluency make all the difference in keeping us interested in the topic from start to finish. Thank you for the excellent work!
9:40 is where you earned my sub. The amazing complexities of the universe are astounding and our grasp on them is so awe inspiring. I can feel in your voice the passion for this! Keep producing content! The world needs this!
I consume quite a bit of physics content on UA-cam, and this video truly stands out as one of the best I’ve seen. I’ve never seen any of your videos before, but I am looking forward to seeing more!!!
I made a boo boo. The formula for the relativistic kinetic energy is WRONG at 0:10! But the concept is accurate and this doesn't affect the rest of the video. Sorry! Thanks Adrian for pointing that out.
After watching and reading so many explanations of time dilation, yours is by far the best, all others always left me with a "weird" feeling of just having to believe, but yours definitely didn't! Very well done! (I also had the question about the ship's perspective, but your second video solves that 🙂)
I've been reading and discussing Sagan's "Cosmos" with my 9yo daughter for a little while, and I just found this video right around when we were talking about time dilation as it appears in the book. I just wanted to say that the video is great and you do wonderful work. I really appreciate your channel, as does my kiddo. Keep up the good work!
Took me a second to realize that what Mahesh calls "t dash" is what I would call "t prime". This was a great video! First time I have ever seen a good explanation of why not just time slows down, but so do actual physical phenomena when approaching the speed of light.
Best explanation I’ve ever seen. I actually understand this one 👍. Thanks!! What you could add is when you go faster and faster, de photons in the clock will describe flatter and flatter lines. At lightspeed they will go horizontal and don’t bounce anymore at all. Hence, time stands still.
I've known about this since high school 20+ years ago, but this is actually the first time I've ever understood why. Thank you so much, you have truly enlightened me, and everything finally makes sense.
It never once occurred to me, that because the speed of light is constant, when an object is moving it effectively means that light has to travel more distance... but it's not going any faster to compensate... and that is literally what time dilation spawns from. I love that. Thanks man.
@@donaldslayer where? how do you test light in another universe when ur in this universe? can't be proven here.... light is a wave, it is slowed down when travelling through a medium, the vacuum of space is not empty..... ever heard of dark matter ? maybe that is what gives light its constant speed.... derrrr
@@donaldslayer the slomo guys only proved that light moving through a medium has a slower speed. (if you don't understand the subject it's generally a good idea to shut up untill you do understand it) light basicly has infinate speed. but only from it's own perspective. from our outside perspective there is still the speed of causality to take into account. the speed of information. if you were a light particle. a photon. you would basicly die as soon as you are born. not even any time to experiance anything. from the exact moment you are emitted. you smack into whatever surface you are shining on. doesn't matter if this is a flashlight shining at a wall. or the light of a star billions of lightyears away reaching your eye. it's in the same exact instant. from the outside looking in however. you move at nearly 300k kilometers per second. 299.792.458 km/s or almost 190k miles per second. 186.000 miles/sec and it's always that speed. no matter how fast you are moving. and no matter in what direction you are travelling. the only thing that can slow light down is it moving through something. like air. or a gel. or whatever. and that's how they slow light down enoegh that you can capture the propegation of reflections move through something with a camera. it's physicly impossible to make a camera fast enoegh to capture the speed of light in a vacuum. because it would take infinate energy.
I just got you channel in my suggestions yesterday and I've been binge watching you since then. You are a great science explainer and I love your willingness to look at the math- I appreciate the people who try to explain without the math, but it's such a crucial part... I look forward to your career taking off.
I finally understand it completely. Thank you sir. My logic and ignorance has had me fighting this theory for years, and my brain finally "clicked" and I now fully understand. Thank you.
This video doesn't just explain why we can't reach speed of light. It explains much more than that. For example, it explains why time slows down when you move very fast, but the moment I felt like I was enlightened by this video was when I realized that this can also explain something that I never understood before. I am talking about how the concept of relative speed doesn't apply to light and we always see the light moving at light speed regardless of our own speed. I still don't understand it fully but I feel like this video gave me a big hint about why that's happening.
I find it useful to consider that ALL objects move at the same speed through spacetime at the rate of c. A stationary object is moving only through time and a photon is moving only through space. Other objects move at different ratios of space vs. time depending on their speed, but an object's speed through spacetime never changes.
So basically two photons are emitted from one source - a lightbulb on a moving spaceship. One hits the eye of a traveler onboard, the other hits yours (and you are outside the ship and at rest in space. Wearing a spacesuit, of course, cause you’re smart). Two possibilities exist: 1. The ship moves away from you. 2. Or towards. In first case photon “forced” to “move” more distance towards yourself than it would’ve if the ship was at rest same as you, in second vice versa. But! And it’s a big fundamental physic’s BUT(t) 😉 Photons always travel at the speed of light at all reference systems, no mater what, so it will reach both of you and the traveler all the same, however it travels as a wave not as particle. And since distance was increased or decreased wave gets “stretched” or “compressed” in spacetime, which means it will have lower frequency in first case and higher in second. So for the traveler it would be ordinary light - nothing’s changed, but for you it would be red-shifted or blue-shifted accordingly. To visualise it: imagine photon as a particle skipping on a bridge. The bridge represents the distance between point of emission(in our case lightbulb) and your eye. At rest everything is simple: photon happily skipped on the bridge towards you at the speed of light and smiles meeting you (because you have inquisitive mind and want to understand him) Now imagine the point of emission goes away from you. Photon looks at the bridge sighs quietly and starts it’s journey at the speed of light as usual. However every jump, the bridge gets stretched a little bit underneath him. So even though our little but very determined photon jumps as high as he can and travels at the same speed of light, he lands a little bit farther away from you and from where he should’ve landed if damn bridge just kept still. But it’s keeps stretching and stretching… Every single jump (how exhausting!) So no matter from what perspective we look at him now we still know it’s a photon because he jumps a photon high and travels at the speed of light. But remember he’s very determined to meet you(for reasons stated previously)! So finally he will reach you, tired and red from exhaustion (poor little fellow is completely red-shifted! now it’s easier to remember which way is which, right?), but of course the distance he traveled was bigger and because we know speed was the same, it means it took more time (v=d/t). In the other case bridge unexpectedly starting to shorten every time he jumps and although he’s very happy about meeting you sooner it’s still freaks him up a little bit too. So he jumps as high as photons should, but his jumps are just shorter this time because the part of the bridge he planed to jump over is became shorter instead (what a world! What a strange world we are all existing in! He probably thinks. Well of course. He doesn’t understand speed - he is born to know only one and never can accelerate or slow down). Nonetheless he reaches you very excited because it took so less time to get to you! He happily bounces around you, but unfortunately you can’t see him he was jumping so closely so short distance he accidentally blue-shifted into blue then violet, ultraviolet and finally into microwave range. But don’t worry science got you both covered. You can still meet with the help of radio-telescope. It will greet photon with it’s antennae and translates him into visible spectrum for you. Happy end. Hope it helps. It’s overly simplified, but at the core is correct. Just remember photons do not (under usual circumstances) propagate as particle in reality. The cake is a lie…. I mean the bridge! 😅 In this visualisation the bridge represents spacetime for the wave to propagate in and the photon represents every other characteristics of light (electromagnetic force). To understand it further we have to dive into wave functions and quantum theory which is beyond the scope of this explanation. Keep asking questions, reading science literature and watching educational videos. See you on the other side of electromagnetic spectrum!
@@huskypup3489I’m so sorry to shatter your understanding, but you’re wrong and Einstein is right. It’s all about reference frame. Objects do travel through spacetime at different speeds depending on point of reference, same as force carrier particles such as photon, we don’t know does the time goes “forward” “for them” or “standing still” or something else entirely, however the can observe and measure their speed, which is constant in any frame of reference, and means they do indeed travel in spacetime. Basically bosons except for mesons are incapable of slowing down beyond light speed in any reference frame, while aforementioned mesons and generally hadrons and fermions can, yet they have mass and are incapable of reaching speed of light instead. Your explanation fails at black holes for example. Gravity there is so strong it stretches spacetime so far that light needs infinite time to travel from source of emission beyond event horizon and since our universe have measurable time frame since the formation of a black hole to any point of time in the future (in our understanding of spacetime at the current state) we can observe no light escapes black holes, which in oneself reinforces our current models. Einstein’s theory explains it perfectly yours doesn’t, sorry. Mathematically speed, time and space come together in this formula v=dt. It’s been tested and always predicted results correctly to a certain degree, you can check yourself if needed. Now if you were right it would mean everything’s speed is c, which is kinda weird on it’s on but harder to debunk in simple terms. So lets look at photons in your model t=0 for them always hence for photon v=0 always 😮 according to your model photons are at perpetual rest to everything in the universe. Incapable of travailing any distance at all. No matter from which point of space or time you look at a photon it should always be at rest relative to you! So sorry again but it’s better to be mistaken and find out then believe in a wrong thing, you on the right trek just didn’t reached the destination yet. Be patient and eventually everything will click into places. By the way interesting thinking, never heard something like this, made me think for a second, thank you for what! I can recommend to start from understanding that space and time are kinda sorta the same thing like matter and energy is. Not exactly but it’s a good enough start, what is established for now is they are intrinsically connected and inseparable hence the actual name spacetime. It’s just describes four dimensions of the universe which we can confirm at the moment. Good luck, hope I’ve been helpful and didn’t dissuaded you from digging deeper, it’s crazy out there, but fun I promise.
@@Noblp As @huskypup3489 said C is constant for everything, which means that speed through space and rate of time trade-off in a reciprocal relationship when comparing two frames of reference, otherwise known as relativity. For an excellent visual representation and explanation watch the video called "We all move at the Speed of Light."
Reading the chapter about atoms in Richard Feynman's Six Easy Pieces led to an epiphany and an entirely new view of nature for me. It was the moment that atomic theory finally really "clicked" for me. I think I've just experienced that feeling again for SR after watching your explanation! By far the best, most intuitive explanation I've seen.
It has been so long since I read that book. I can say that I effectively remember nothing from the book. I have knowledge but by now at nearly 60 it is hard to keep track of where my knowledge came from . In short, would you mind offering a brief explanation of the epiphany?
@@kfawell It's been years since I read it and don't remember the specifics of what led to the epiphany, but I definitely remember the emotional feeling of that "aha!" moment. I think he was describing either evaporation or condensation, and how the normal interaction of atoms leads to these as emergent phenomena.
I cant recall the number of videos on the subject and i never quite felt like i got it. Thanks to you and your ability to communicate so well, i finally got it. Keep up the great work!
Just incredible. You have the very rare talent to explain these very complex issue to non physicists so they are actually getting it, only by use of a few graphs and your unique way of breaking the basics down. Never seen anything like this before. Greatest respect to you. And a huge THANKS.
Thank you... I've been looking for some intuitive explanation of this as I was finding the whole space/time principle quite hard to really get an understanding of. This has really helped and I'm so grateful.
The knowledge, the passion, You sir are a born a brilliant teacher. After years, someone finally explained it to me in a way it's intuitive. for me you won't the internet today!
This guy is my absolute favorite science communicator. Keep it up Mahesh! If we had more professors as excited as him, to teach their respective subjects, kids would definitely be doing better in school.
I had always heard about the infinite energy and kind of understood but now that I know that it is required to make up for the time dilation it makes total sense. …and for relativity that is saying something. Bravo!
This is probably the 20th video I have watched about time dilation and none of the other videos explained it this well. I’ve never felt closer to an understanding of the concept. THANK YOU!! This video (and you) are a pleasure to watch. I do have some questions. If you are inside the ship and in a room with no windows as the ship is nearing the speed of light, what would you see when you looked toward the front of the ship? What would you see when you looked toward the back of the ship? How would photons of light behave within that room? It seems that the room toward the back of the ship would be very dark because fewer photons per second were reaching your eyes. Conversely, the front would seem much brighter because you would be receiving an overdose of photons per second.
these are the most intuitive explanations of general relativity ive ever sen. absolutely fantastic work. i also apprciate that you stay inside the scope of experimentation too. mathematical validity does not necessarily imply metaphysical status and its really easy for communicators to get off in the weeds when straying too far from whats observable, which you do not do.
@@Mahesh_Shenoy Will you answer a question for me please? A photon takes 8 minutes to get from the Sun to Earth. If we see the ship traveling the same distance toward us at just under the speed of light, then why would time dilation cause the ship to take nearly a day to reach us instead of just over 8 minutes? 8 minutes x 70 = 23.3 hours.
What I find interesting is how many different ways you can interpret Relativity and get the same outcome. You could also show that as velocity increases, length contracts along the direction of motion. As you accelerate, the apparent length shrinks so that the muon lives the same time, but the distance to Earth is shorter. Also, since length contractions is exponential, the faster you go, the more contracted the increase in distance the new velocity delivers. At c, the length is 0 so any increases in speed adds 0 more distance per time.
Maybe I'm looking at it differently, but lengths (distances) obviously don't change, whereas the time changes can easily be measured. I see what you're getting at, the apparent distance is shorter because your speed is greater, so it takes less time to get there. That, however, is not what is actually happening. Time is the variable, not distance.
@@briandbeaudin9166 You say "apparent" distance, implying there is a universal distance all can agree upon. However, in Relativity, the only things all observers can agree upon are the speed of light and cause/effect. Distance and time are observer dependent.
Agree with DJ_Force regarding distance & length being dependant on observer reference frame. Look-up "the ladder in the barn paradox" @@briandbeaudin9166
Finance and Data Analytics guy here, passionate about math and astrophysics just got the most clearest explanation of why we can't reach speed of light on a random Saturday at 2 AM. Thanks for dumbing it down for us, and your enthusiasm !!! You just gain a subscriber.
I am not a Math person and I can easily get lost in it but you just made this video very easy to understand the math here. Thank you and yes keep infinitely doing what you do👍🏼👍🏼👍🏼
bro, this was amazing. the question that I had since decades, the question that noone could answer, finally its before me. Thanks for this!! At every step I was asking "but what about that?" and you brought that exact same question and answered it beautifully. Salute to you sir.
hi people , i am from brazil. its amazing how your " level" of problem is trying to understand this really complicated topic. i want you people to understand, the reason why america is such a great country is because there are people in the comments trying to explaing to a 9 years old daughter about relativity. THIS is the reason, you guys get curious about something and try to investigate. That is what makes your society way more advanced than 3rd world countrys. Here, people are proud of being ignorant about things..... congratulations to everyone who watched this video, i hope your life is full of blessing, please raise your children to be curious about the universe and ask questions. Never let your country become what is happening around the world.
You deserve a Nobel Peace price for this explanation. I have been listening to proclaimed scientists on UA-cam trying to explain this phenomenon and none comes close. You are a hero. Keep'em coming baby
You are really making great videos. I would like to add a suggestion to you as a learner that please make more video on complex ideas of quantum mech and black hole physics.... classical physics(emt,str,gtr) are totally intitiutve but modern theories sometimes creates conflicts
Great video! You're very passionate explaining this stuff, and you made every step easy to understand to, i believe, everyone. You kind of broke down the idea that I had before which was somehow the object becoming heavier as it sped up, or something that is not very intuitive like that. BUT (it wouldn't be a UA-cam comment without a but...) I was really expectant, as a follow-up towards the end, of the explanation of why the ship can't reach the speed of light but from the perspective of the ship, since the time for the passengers inside the ship is the time proper. Right? They would just keep "feeling" (well, dead) an insane acceleration of 1000m/s/s instead of it starting to decrease more and more, right? Or would they start feeling at some point "hey we're accelerating at just 1g now"? The intuition that I gained from your video left me with the idea that to those inside the ship, it can accelerate normally +1000/s every second until it reaches the speed of light without anything there making it harder and harder, or even stopping them from surpassing it, from the POV of the passengers. But their time would be moving "faster", so when they reached the speed of light, the universe would be long dead, since they took forever, but from their perspective it was just another second to add +1000m/s to the speed? I think I'm very wrong here so this gave me a bit of a sense of non-closure on the topic 😅 But I assume there's just another perspective of the same Physics and Math equally making something there equally infinite, or zero, and I love to know what is it and how to understand that in an intuitive way like what you did from an external perspective, as well!! Pleeeease follow-up video/short/comment whatever! I must know! x'D
Hi mahesh, i’ve wrote you this message on instagram but you didn’t saw it. So ill put it here. Hello dear mahesh! Im writing you from Israel. Im a physics student thats waiting to start his last year in the university towards getting my first degree in physics. Im sure you’ve heard about the war thats going on in here, and because of that the university keep on delaying the start of the semester, so i didn’t learn physics in the past 6 months :(. Thankfully, i’ve came across your great youtube videos, and even though i’ve already learned most of the topics that you are talking about, i’m having a great time watching them. It really makes me feel better in those tough days. So I just wanted to thank you personally, and tell you to keep up with those amazing videos. Thank you So much❤️
I had already understood the topic, played that experience game that shows visually what time dilation would look like, understood the examples of being in the event horizon and looking like you froze while you're moving, and this still showed a whole new view on what practically would be the experience, like isolating other constant than what I'm used to isolating. Great video. After years of thinking you grasp something, there's always a new view on that to make you understand that something better. Thanks for the damn good work!
Hey mahesh as always great video but I have a question. If I was in the spaceship then time would pass normally for me. And now if I’m at 99.99% c and If I just became faster wouldn’t I reach c out of my perspective ? For others it would take endless time but for me it wouldn’t or ? I don’t see my mistake in here but there surely is. Because for someone traveling at for example 1/2c his time would have been normal for him. So 10 years for him but on earth 100 years. And now can’t I say yeah I reach c but for others that time dilation is so big that it is infinite for them?
I think you're right, but by the "time" you reach c, the universe (everything that isn't travelling at 'c') will be "dead", consumed, in a black hole, transformed into iron, or whatever the end looks like. Also, the probability of you NOT hitting a grain of dust must be 0, so you'd be dead too because of that.
It kinda a head nut yes. I'm with you cause I thought the same. But you the passenger would still age slower cause you travel at almost luminar speed. Therefor the "real" time slows down indeed. For you too, cause your removing so fast. Imagine going earlier outside for work, you would probably arrive earlier on work then right? Since hypothetical time would get to a hold at direct lightspeed, making you either immortal, as long as you move that fast, kills you instantly cause your life will be over in seconds in a "natural" way or you outright freeze in time and Every move takes infinite time to make. Let's say time slows down to 0 at lightspeed. That would mean that at 99 percent of ls the accelerating would take longer, like he said in the video. Time slows down ultimately for us,maybe without noticing, but we'd still be several centuries old when we arrive at our destination. The only question would be if we re dead or Alive. Let's say ls.travel is possible, would it instantly jump to the moment that we slow down (however that works) and arrive at the destination? Cause we weren't experiencing time, so we didn't had for time to pass. Tho for an observer it would take us for example 4,5 ish years to get to aloha centauri. I should get to an end, my head smokes.
If a stationary person is seeing a moving person's clock move slower, then the moving person would see the stationary person's clock moving faster. But from the moving person's perspective, they themselves are stationary and also from the moving person's perspective, the stationary person is moving; so the moving person would see the stationary person's clock moving slower not faster. I never understood this part of special relativity. Could someone explain it?
well you answered it yourself, now moving person is stationary from his perspective and stationary person is moving with the opposite vector 'c' and above explanation fits this scenario too, and hence it moves slower for both the person from their perspective as stationary. for more clarity please watch from 3:00
Im not a science guy but im curious to know why it matters what the speed of spaceship appears from outside. I mean, if it's goin at the speed of light why should the outside perspective matter?
For the spaceship itself time will tick slower, that's what he explained with the help of half life and muons example. So while approaching speed of light it will take infinite time/finite enegry OR finite time/infinite energy
A question I've always had but haven't the math to understand: If two photons (call them Alpha and Beta) are sent out from Earth in opposite directions, each traveling at c. Where Alpha is represented as -c with respect to Earth and Beta is moving at +c with respect to Earth. We now change our referent from Earth to Alpha. Earth now holds a relative velocity of +c relative to Alpha, would Beta not then hold a relative velocity of +2c relative to Alpha? How does this square with the speed limit of c? Does time dilation change the relative value of velocity such that the perceived speed of Earth from Alpha is
You can't do that. Light always travels at c, in all reference frames. This means that light itself does not have a valid reference frame (since there is no frame in which light is stationary). If instead α and β were particles travelling very close, but not quite at, the speed of light, then you could use the "Velocity Addition Formula" to find out the the relative speed between them (which will always be less than the speed of light).
Fantastic explanation. Still a little confused though! From an observer's perspective the ship with constant thrust will take forever to attain c due to time dilation, but from the perspective of someone on the ship they do not experience time dilation so what prevents them attaining c after the required number of speed increments? What would someone on the ship perceive as happening?
Since any amount of time passage from their perspective now equals infinity for the rest of the universe, I suppose what they would experience is instantaneous end of the universe :)
How does this work for the observers on the space ship as it approaches C? The observers on the craft would still see light move at C and the ships particles would interact with eachother at C. So couldn't the observers on the ship reach C from their perspective? (Asuming you don't care the heat death is occurring outside your craft as near infinate time passes ouside the ship)
I was wondering this too. I suppose the explanation is that it takes infinite energy so it's just not possible. But if we ignore energy then when you reach the speed of light all time instantaneously happens outside of your space ship all at once and you would observe all of it in that very moment. It would just be a bright flash of light I guess. And then what? You could slow down but what happens, when you are outside of all time. You have gone beyond an infinite amount of time. It makes no sense, so luckily infinite energy is impossible to avoid that paradox.
@@asleepappeal so, if you reach the speed of light, you would theoretically generate infinite mass as well right? At the point of infinity, when your spaceship finally reaches the speed of light, it's infinite mass would literally suck in everything in the universe as the biggest supermassive black hole to ever exist and annihilate the universe. Theoretically. I think the concept of infinity in general just breaks everything
Also, what does proper time even mean. The universe does not have a preferred reference frame. The person, once he stopped acceleration, no longer is anything special. In his pov everything else is moving but him. So everything else is experiencing time dilation. To answer your question tho, length contraction, the universe appears to become very short.
![Why can't you still reach light speed? [Intuition using length contraction]](http://i.ytimg.com/vi/6wXwfcFYKLE/mqdefault.jpg)
![Why can't you still reach light speed? [Intuition using length contraction]](/img/tr.png)
I heard you folks!
What do we see from the ship’s perspective?
Here you go - ua-cam.com/video/6wXwfcFYKLE/v-deo.html
Hint: We discover the second consequence of special relativity. (one more to go)
Yeah, this explanation that you give requires the establishment of an absolute reference frame. If we can do that, then time dilation and length contraction are real phenomena.
Otherwise, if we can't define an absolute reference frame, and spacetime really is absolutely relative - then time dilation and length contraction are NOT real phenomena, but simply visual illusions like the ones we get when we put a spoon inside a glass of water... The spoon doesn't change shape...
So yes, a lot can be said about this, and honestly, I don't think that a full explanation really exist. Not even Einstein was sure what to make of all that. As for someone who has read his actual books, along his life, he was constantly changing his mind about if an absolute reference frame really exists or not...
I like this guys explaination it is superb. God bless you bro thank you .
I guess you won't notice the dilation from inside the ship, since it affects you as well, ship keeps accelerating at a constant rate, getting you to Lightspeed eventually.
But you might arrive a couple of million years late at your destination. Ooops
@Mahesh_Shenoy
I think that you are trying to say that the speed of an object is an inherent attribute of that object - and its not.
For example, a neutrino - ISNT traveling close to the speed of light.
Its only traveling close to the speed of light RELATIVE to us here on Earth.
There should exist, at least 1 observer out in the Universe that measures the speed of that same neutrino and finds it to be equal to that of a bike...
So what is it? Is the neutrino traveling close to the speed of light or the speed of a bike?
Neither. The ONLY way to know the speed of a neutrino is if we had a global refference frame, which is absolute, and then yes - then we would be able to assign "close to lightspeed" as an inherent ATTRIBUTE to that netutrino. We will know for sure its exact speed relative to that 1 absolute frame.
So to ask "Why can't something travel at the speed of light" is a question that implies - that we can somehow measure the exact speed of an object... Which in turn implies that there is a global refference frame that will give us that knowledge.
Neither of these are shown to be true; The speed of light being a speed limit CANT be explained using relativity - because its an AXIOM of relativity.
Well, it's fine, but it's basically theoretical. We currently have a very surface level understanding of the universe and its physics. We know the results but not really the underlying structure that determines the results.
It's like understanding a car's functions, what it can and can't do, but having no knowledge of the engine, drive train, suspension, cooling. You only see the results and don't actually understand how the car works. So you keep pushing to see if the car can, in fact, do things it's not supposed to be able to and accept the results even though your lack of understanding of the components that make up the car could be the reason you are getting the results and not that your results are definitive.
After 38 years finally someone came along to explain this phenomenon in an intuitive and understandable way. Thank you for finally making me understand what is going on! 🙏
Well one thing always ruins the logic. He said the clocks time is affected when in motion. Motion however is relative, so you, observing the clock, are also moving sideways relative to the clock.
So how does the universe decide which time frame slows in relation to the other? They cant both slow down.
@@Zach-mi6tobecause there is no universal frame of reference. This is all relative to something, a clock at rest compared to the moving object (relative to the resting clock). There is no universal frame or clock. Everything is relative to whatever resting object you measure from.
In essence: you need to unthink the universal frame of the universe that feels intuitive. It doesn't exist.
@@BooleanDisorder u r missing your own point. There's no such thing as a "resting" reference point. There is no resting clock, bc as u mention, there's no universal reference. That's my point.
@@BooleanDisorder with acceleration yes, it then becomes an asymmetrical equation and dilates time just like a gravitational field. But two objects in uniform relative motion, for both to experience a slowing of time would suggest they are each creating a new version of reality. Or something like that. Doesn't make sense but maybe there's a consensus answer somewhere.
It is not a phenomenon it is a theory.
You have no idea how good you are at explaining stuff. Genius!
Super glad that you think so!!!!
Yes I agree he did an amazing job
Hi Mahesh!! Can you make a video about Cherenkov radiation? Why does a charged particle emit electromagnetic radiation when it is traveling through a medium at a speed greater than that of light through the medium? @@Mahesh_Shenoy
Massive thanks for this video, I haven't heard anyone explain this as good as you before!
He blew my mind
this guy is THE BEST, MOST CLEAR EXPLAINER, after 50 years of attending lecttures, reading hundreds of books. the guy has a gift... thank you so much
The most intuitive explanation of time dilation I've seen, and the animations are clear and well done. Fantastic video :)
They say there is always an Indian guy on UA-cam with a tutorial for any topic. Now an Indian guy made the best tutorial for relativity. I guess we can see "how to build a time machine" tutorial soon from some Indian guy. Amazing job.
Hey , how is the war economy going on in Russia?
Regards from India🇮🇳👳🏻♂️
Ohh poor soul because Everything originated from India
@@ramrave2913including poverty and corruption
@@ramrave2913 kuch bhi chu
???? I think you mean USA
😮 You taught me in 16 minutes something I wasn't able to understand after years of self-study! 👏👏👏🙌🙏
You might want to learn something a little easier if it took you years to not learn something.
Don't worry you still haven't learned anything
You still don't understand, you just think you do
Sorry to hear that man. I dropped out of school due to the side effects of a nasty head injury that also left a ceramic plate on the left side of my head. But despite teachers thinking that I was just one step away from being labeled as "Mentally Challenged", I still managed to independently discover the special relativity(SR) phenomena, derive the SR mathematical equations, along with independently deriving the Lorentz transformation equations, and the method that I used to derive these equations has not even been thought of by others as of yet.
This thread cracks me up. A self deprecating post by a confident person and a bunch of low self esteem jackasses piling on. "Sorry you not smart. Me understand everything because ceramic brain." It's pretty hilarious to me.
Wow. I have read countless Quora posts/comments, watched many YT vids, read science mags, articles, etc. and this FINALLY explained it to me. Only took like 40 years! Thanks so much for what you do.
Wow, thank you :)
I've read the same concept in two different text books for hours... But this man gave me the complete intuition in just 16 minutes... Hats off to your work sir...
Everybody who makes physics videos talk about time dilation and special relativity.. but no one explained it as intuitively and as simply as you did, I have stumbled upon time dilation equation many times and never seemed to understand where it came from... But now I can perfectly see it and make sense of it, keep up this beautiful work and I am deeply grateful for your efforts
Agreed. Best layman’s terms breakdown while still utilizing the actual science involved.
I believe that’s because they don’t understand it either. They just regurgitate information. If one can break down information to an intuitive level then one has truly understood it.
Just remember there are 1000s of videos explaining why the earth is flat and the moon doesnt exist
My man. This was one of the most joyous videos I’ve ever watched on physics. Your joy is contagious and I love every second of it. Love the way you explain everything and your emotion behind it all.
You, sir, are a gift to physics students everywhere!
I’m 52 and have a college degree (granted in history) and am also a big sci fi guy. This is the first explanation I’ve heard that actually made sense, even in physics classes.
Thank you.
so essentially you don't have a college degree
@redbean9410 ???? You do understand that history as a field of human knowledge is older than any natural science, right?
@@teacher_fher lmao okay and? a history degree isn't gonna get you anything, except maybe a job as a history professor lmao
Despite the rude jabs here..."Oh the Humanities!"....your statement is very common in our population.
Many people highly educated or stopping at HS are highly specialized in education today. There are far fewer hard sciences students than non empirical students in most of society.
However there are a great number of Sci Fi fans that have picked up science sounding terms but applied by fantasy writers as a vague technobabble.
I (physical chemist) run into a lot of people that insist they understand and are experts on some material theory or another (astrophysics, medicine, chemistry, biology, geology, etc...). Yet in casual conversation I can often find out exactly where they picked up the idea.
I'm sure you find the same is true when you meet someone that learned history at the box office. History is a fine and honorable degree and profession.
@@STho205 there’s less hard science students because it’s not for everyone. Most people can’t obtain the degrees for those jobs
This was the best explanation ever. You’ve asked the same questions I had, a real clock and now I understand why we simplify it. Thank you for this in depth answer. My physics professor just keeps saying well you can’t travel at the speed of light, you just can’t, doesn’t provide an answer. Now finally I understand why time dilation matters. ❤
And because of time dilation combined with dividing by 0 to unleash the power of quantum effects, the light barrier can be broken, all we need is to make such machine that can divide by 0, a computer high-tech enough to program such machine, and fuel potent enough to allow the machine to use quantum effects. As long as we break away, everything becomes possible.
@@AlbertTheGamer-gk7snThis is utter nonsense.
Yes lmao @@markiv2942
2 AP classes in high-school, and 4 years of high level mathematics in college, but the random guy I find on youtube explains this better than any teacher or professor I've ever had.
Uau... That school was really bad.
It’s all in the accent jjones503.
Let's be real. You never paid attention in school. U just wanted to get thru the exams. Even if u had a good teacher wouldn't care
@@manan-543 I tried to pay attention, but got tired of paying someone to tell me which page to read just for a piece of paper.
@@manan-543 yes never blame teachers, first of all today education is business
ahh! For years, now I have gotten the video which almost explains me why can't we reach the speed of light. Great one. And the best part is you are more excited to explain it.
With no exaggeration, this man and his videos should be in every high school and college classroom. I've struggled with this topic for years and in two 15-20 minute videos, he clearly and concisely explains time and distance dilation in a way that someone like me, with a great interest in astronomy/physics/special relativity but who does not possess a degree in these areas, can understand. Furthermore, the way he unfolds the narrative, like a building conversation with Einstein and with his contagious excitement of the topic and of finally understanding it sprinkled in, completely amplifies the greatness here. Well done! You've earned a life-long subscriber.
If you think what he says makes sense you are still struggling
@@royfeigel2535 What this video does is explain time dilation in a way that can be easily understood. I now grasp the concept. I do not understand it, but If I were to learn the details I would be able to link the equations with my understanding of the concept to fully grasp it
same!
Who want Mahesh to infinitely keep making videos?
🥺 No way, that's too long, poor Mahe🥺
✋️
That would need infinite time and/or energy...
So easily explained....plz make such videos
🖐🏼
I love how you are asking common senses questions (and answering them). Questions most of us can't get answered by physicists because they are incapable of stepping out of their wrote explanations. Great job.
This is literally the best illustration of special relativity and time dialation. I don't think anyone has explained it better. Thank you for making it so clear.
No other video on this topic has explained it as well as you have. I suddenly am able to comprehend time dilation and why it actually happens. You are an awesome teacher!
Absolutely adore your excitement and the love that you put into the content you produce. Never understood time dilation until now, and your joy from physics is contagious :) Please continue with such a high quality content! :D
Why isn't your channel way more popular!? Holy crap. I literally understood everything... 🤯🤯 your video also clarified a lot of things "explained" by other videos and other people and other writings.
This is the best science communication channel I have ever found. Your excitement while explaining is contagious. I really enjoy the passion with which you teach. You truly love what you do. Your teaching style and verbal fluency make all the difference in keeping us interested in the topic from start to finish. Thank you for the excellent work!
Your ability to explain complex physics in a way dummies like me can understand is amazing. Excellent 👌
9:40 is where you earned my sub. The amazing complexities of the universe are astounding and our grasp on them is so awe inspiring. I can feel in your voice the passion for this! Keep producing content! The world needs this!
Me too, just now
Read your comment before reaching 9:40... so, of course, I had to keep watching to see what inspired you. Pretty cool stuff. :)
3:57 REAL PHYSICAL CLOCKS SLOW DOWN WHEN THEY'RE MEWING!! 🤫🧏
🕓🤫🧏♂️
I consume quite a bit of physics content on UA-cam, and this video truly stands out as one of the best I’ve seen. I’ve never seen any of your videos before, but I am looking forward to seeing more!!!
I think I’ve watched hundreds of videos on this, and yours is the first one that actually made sense. You definitely have a gift. Thanks.
It's great to see someone explaining what he loves with so much passion.
I made a boo boo. The formula for the relativistic kinetic energy is WRONG at 0:10! But the concept is accurate and this doesn't affect the rest of the video. Sorry! Thanks Adrian for pointing that out.
Keep up the good job.
Sheldon Cooper said the same thing when he gave Dr Stephen Hawking his paper with a math error I believe 😅 Context: The big Bang theory
@@Agni_Puthra Oh really? :D Haha.
@@Mahesh_Shenoy To quote him, "Oh my gosh golly! I made a boo boo... And I gave it to Stephen Hawking" and then he faints...
I like your videos. How can we explain the biological aging difference in the twin paradox ?
After watching and reading so many explanations of time dilation, yours is by far the best, all others always left me with a "weird" feeling of just having to believe, but yours definitely didn't! Very well done! (I also had the question about the ship's perspective, but your second video solves that 🙂)
I love the joy in your face when explaining this. Thanks and keep up the great work. :)
I've been reading and discussing Sagan's "Cosmos" with my 9yo daughter for a little while, and I just found this video right around when we were talking about time dilation as it appears in the book. I just wanted to say that the video is great and you do wonderful work. I really appreciate your channel, as does my kiddo. Keep up the good work!
google spies
Took me a second to realize that what Mahesh calls "t dash" is what I would call "t prime". This was a great video! First time I have ever seen a good explanation of why not just time slows down, but so do actual physical phenomena when approaching the speed of light.
Ah yes! I could have used the same lingo! Prime would have made it that much easier. Great feedback to be mindful about using shared vocab!
Best explanation I’ve ever seen. I actually understand this one 👍. Thanks!! What you could add is when you go faster and faster, de photons in the clock will describe flatter and flatter lines. At lightspeed they will go horizontal and don’t bounce anymore at all. Hence, time stands still.
I've been trying to find an intuitive understanding of time dilation beyond the photon mirror for over a decade. Thank you ❤
I've known about this since high school 20+ years ago, but this is actually the first time I've ever understood why. Thank you so much, you have truly enlightened me, and everything finally makes sense.
This was brilliant. Thank you.
Mastering knowledge means being able to transfer it effectively within simple terms. Well done.
Only someone who REALLY understands this kind of stuff can explain it this well, while being this excited about it! 🥳
Man this is the best explanation of Time dilation and I have seen many videos on this subject. Thank you 🙏👏
It never once occurred to me, that because the speed of light is constant, when an object is moving it effectively means that light has to travel more distance... but it's not going any faster to compensate... and that is literally what time dilation spawns from. I love that. Thanks man.
speed of light is infinite
@@seawaterjohnmiller7118huh
@@seawaterjohnmiller7118the slow mo guys disproved this
@@donaldslayer where? how do you test light in another universe when ur in this universe? can't be proven here.... light is a wave, it is slowed down when travelling through a medium, the vacuum of space is not empty..... ever heard of dark matter ? maybe that is what gives light its constant speed.... derrrr
@@donaldslayer the slomo guys only proved that light moving through a medium has a slower speed.
(if you don't understand the subject it's generally a good idea to shut up untill you do understand it)
light basicly has infinate speed. but only from it's own perspective.
from our outside perspective there is still the speed of causality to take into account. the speed of information.
if you were a light particle. a photon. you would basicly die as soon as you are born.
not even any time to experiance anything. from the exact moment you are emitted. you smack into whatever surface you are shining on.
doesn't matter if this is a flashlight shining at a wall. or the light of a star billions of lightyears away reaching your eye.
it's in the same exact instant.
from the outside looking in however. you move at nearly 300k kilometers per second. 299.792.458 km/s or almost 190k miles per second. 186.000 miles/sec
and it's always that speed. no matter how fast you are moving. and no matter in what direction you are travelling.
the only thing that can slow light down is it moving through something. like air. or a gel. or whatever.
and that's how they slow light down enoegh that you can capture the propegation of reflections move through something with a camera.
it's physicly impossible to make a camera fast enoegh to capture the speed of light in a vacuum. because it would take infinate energy.
I just got you channel in my suggestions yesterday and I've been binge watching you since then. You are a great science explainer and I love your willingness to look at the math- I appreciate the people who try to explain without the math, but it's such a crucial part...
I look forward to your career taking off.
I am amazed how simplified explanations you come up with complex concepts. Hats off to you 👏 🙌 🙏
Your enthusiasm for this subject is infectious. Thank you
I finally understand it completely. Thank you sir. My logic and ignorance has had me fighting this theory for years, and my brain finally "clicked" and I now fully understand. Thank you.
This video doesn't just explain why we can't reach speed of light. It explains much more than that. For example, it explains why time slows down when you move very fast, but the moment I felt like I was enlightened by this video was when I realized that this can also explain something that I never understood before. I am talking about how the concept of relative speed doesn't apply to light and we always see the light moving at light speed regardless of our own speed. I still don't understand it fully but I feel like this video gave me a big hint about why that's happening.
I find it useful to consider that ALL objects move at the same speed through spacetime at the rate of c. A stationary object is moving only through time and a photon is moving only through space. Other objects move at different ratios of space vs. time depending on their speed, but an object's speed through spacetime never changes.
So basically two photons are emitted from one source - a lightbulb on a moving spaceship. One hits the eye of a traveler onboard, the other hits yours (and you are outside the ship and at rest in space. Wearing a spacesuit, of course, cause you’re smart). Two possibilities exist: 1. The ship moves away from you. 2. Or towards. In first case photon “forced” to “move” more distance towards yourself than it would’ve if the ship was at rest same as you, in second vice versa. But! And it’s a big fundamental physic’s BUT(t) 😉 Photons always travel at the speed of light at all reference systems, no mater what, so it will reach both of you and the traveler all the same, however it travels as a wave not as particle. And since distance was increased or decreased wave gets “stretched” or “compressed” in spacetime, which means it will have lower frequency in first case and higher in second. So for the traveler it would be ordinary light - nothing’s changed, but for you it would be red-shifted or blue-shifted accordingly. To visualise it: imagine photon as a particle skipping on a bridge. The bridge represents the distance between point of emission(in our case lightbulb) and your eye. At rest everything is simple: photon happily skipped on the bridge towards you at the speed of light and smiles meeting you (because you have inquisitive mind and want to understand him) Now imagine the point of emission goes away from you. Photon looks at the bridge sighs quietly and starts it’s journey at the speed of light as usual. However every jump, the bridge gets stretched a little bit underneath him. So even though our little but very determined photon jumps as high as he can and travels at the same speed of light, he lands a little bit farther away from you and from where he should’ve landed if damn bridge just kept still. But it’s keeps stretching and stretching… Every single jump (how exhausting!) So no matter from what perspective we look at him now we still know it’s a photon because he jumps a photon high and travels at the speed of light. But remember he’s very determined to meet you(for reasons stated previously)! So finally he will reach you, tired and red from exhaustion (poor little fellow is completely red-shifted! now it’s easier to remember which way is which, right?), but of course the distance he traveled was bigger and because we know speed was the same, it means it took more time (v=d/t). In the other case bridge unexpectedly starting to shorten every time he jumps and although he’s very happy about meeting you sooner it’s still freaks him up a little bit too. So he jumps as high as photons should, but his jumps are just shorter this time because the part of the bridge he planed to jump over is became shorter instead (what a world! What a strange world we are all existing in! He probably thinks. Well of course. He doesn’t understand speed - he is born to know only one and never can accelerate or slow down). Nonetheless he reaches you very excited because it took so less time to get to you! He happily bounces around you, but unfortunately you can’t see him he was jumping so closely so short distance he accidentally blue-shifted into blue then violet, ultraviolet and finally into microwave range. But don’t worry science got you both covered. You can still meet with the help of radio-telescope. It will greet photon with it’s antennae and translates him into visible spectrum for you. Happy end.
Hope it helps. It’s overly simplified, but at the core is correct. Just remember photons do not (under usual circumstances) propagate as particle in reality. The cake is a lie…. I mean the bridge! 😅 In this visualisation the bridge represents spacetime for the wave to propagate in and the photon represents every other characteristics of light (electromagnetic force). To understand it further we have to dive into wave functions and quantum theory which is beyond the scope of this explanation. Keep asking questions, reading science literature and watching educational videos. See you on the other side of electromagnetic spectrum!
@@huskypup3489I’m so sorry to shatter your understanding, but you’re wrong and Einstein is right. It’s all about reference frame. Objects do travel through spacetime at different speeds depending on point of reference, same as force carrier particles such as photon, we don’t know does the time goes “forward” “for them” or “standing still” or something else entirely, however the can observe and measure their speed, which is constant in any frame of reference, and means they do indeed travel in spacetime. Basically bosons except for mesons are incapable of slowing down beyond light speed in any reference frame, while aforementioned mesons and generally hadrons and fermions can, yet they have mass and are incapable of reaching speed of light instead. Your explanation fails at black holes for example. Gravity there is so strong it stretches spacetime so far that light needs infinite time to travel from source of emission beyond event horizon and since our universe have measurable time frame since the formation of a black hole to any point of time in the future (in our understanding of spacetime at the current state) we can observe no light escapes black holes, which in oneself reinforces our current models. Einstein’s theory explains it perfectly yours doesn’t, sorry. Mathematically speed, time and space come together in this formula v=dt. It’s been tested and always predicted results correctly to a certain degree, you can check yourself if needed. Now if you were right it would mean everything’s speed is c, which is kinda weird on it’s on but harder to debunk in simple terms. So lets look at photons in your model t=0 for them always hence for photon v=0 always 😮 according to your model photons are at perpetual rest to everything in the universe. Incapable of travailing any distance at all. No matter from which point of space or time you look at a photon it should always be at rest relative to you! So sorry again but it’s better to be mistaken and find out then believe in a wrong thing, you on the right trek just didn’t reached the destination yet. Be patient and eventually everything will click into places. By the way interesting thinking, never heard something like this, made me think for a second, thank you for what! I can recommend to start from understanding that space and time are kinda sorta the same thing like matter and energy is. Not exactly but it’s a good enough start, what is established for now is they are intrinsically connected and inseparable hence the actual name spacetime. It’s just describes four dimensions of the universe which we can confirm at the moment. Good luck, hope I’ve been helpful and didn’t dissuaded you from digging deeper, it’s crazy out there, but fun I promise.
@@Noblp As @huskypup3489 said C is constant for everything, which means that speed through space and rate of time trade-off in a reciprocal relationship when comparing two frames of reference, otherwise known as relativity. For an excellent visual representation and explanation watch the video called "We all move at the Speed of Light."
The speed of light being constant is a convention though, it could just be that the speed really is different in different directions.
Reading the chapter about atoms in Richard Feynman's Six Easy Pieces led to an epiphany and an entirely new view of nature for me. It was the moment that atomic theory finally really "clicked" for me. I think I've just experienced that feeling again for SR after watching your explanation! By far the best, most intuitive explanation I've seen.
It has been so long since I read that book. I can say that I effectively remember nothing from the book. I have knowledge but by now at nearly 60 it is hard to keep track of where my knowledge came from .
In short, would you mind offering a brief explanation of the epiphany?
@@kfawell It's been years since I read it and don't remember the specifics of what led to the epiphany, but I definitely remember the emotional feeling of that "aha!" moment. I think he was describing either evaporation or condensation, and how the normal interaction of atoms leads to these as emergent phenomena.
@@jeffwilson3818 thanks for telling me. I guess a good plan would be for me to read it again.
I always admire the way you simplify and scientifically analyse the theories.
Man, you’re so good teacher! This content is definitely underrated. Wish you the best, man. Keep up a great work.
I cant recall the number of videos on the subject and i never quite felt like i got it.
Thanks to you and your ability to communicate so well, i finally got it.
Keep up the great work!
Just incredible. You have the very rare talent to explain these very complex issue to non physicists so they are actually getting it, only by use of a few graphs and your unique way of breaking the basics down. Never seen anything like this before. Greatest respect to you. And a huge THANKS.
Thank you... I've been looking for some intuitive explanation of this as I was finding the whole space/time principle quite hard to really get an understanding of. This has really helped and I'm so grateful.
You are brilliant, not only because you understand what you explain, but because you got the amazing talent to explain it to us.
The knowledge, the passion, You sir are a born a brilliant teacher. After years, someone finally explained it to me in a way it's intuitive. for me you won't the internet today!
This guy is my absolute favorite science communicator.
Keep it up Mahesh!
If we had more professors as excited as him, to teach their respective subjects, kids would definitely be doing better in school.
I stumbled upon this video going down the interstellar rabbit hole. Only one word can describe this. WOW!! Explained so much in a simple way. ❤
I had always heard about the infinite energy and kind of understood but now that I know that it is required to make up for the time dilation it makes total sense. …and for relativity that is saying something. Bravo!
This is probably the 20th video I have watched about time dilation and none of the other videos explained it this well. I’ve never felt closer to an understanding of the concept. THANK YOU!! This video (and you) are a pleasure to watch. I do have some questions. If you are inside the ship and in a room with no windows as the ship is nearing the speed of light, what would you see when you looked toward the front of the ship? What would you see when you looked toward the back of the ship? How would photons of light behave within that room? It seems that the room toward the back of the ship would be very dark because fewer photons per second were reaching your eyes. Conversely, the front would seem much brighter because you would be receiving an overdose of photons per second.
these are the most intuitive explanations of general relativity ive ever sen. absolutely fantastic work. i also apprciate that you stay inside the scope of experimentation too. mathematical validity does not necessarily imply metaphysical status and its really easy for communicators to get off in the weeds when straying too far from whats observable, which you do not do.
I love these intuitive explanations! This is where elegance and beauty emerge!
Love your videos and your energy Mahesh, makes me very interested in physics. Thank you very much!
Great to hear that, buddy 🤗
@@Mahesh_Shenoy Will you answer a question for me please? A photon takes 8 minutes to get from the Sun to Earth. If we see the ship traveling the same distance toward us at just under the speed of light, then why would time dilation cause the ship to take nearly a day to reach us instead of just over 8 minutes? 8 minutes x 70 = 23.3 hours.
You did a pretty good job at explaining this. FAR better than the professors did back in the day when I was a college student.
Your enthusiasm for physics is simply inspiring. Keep up the good work!!
What a BEAUTIFUL explanation! I got ever confused reading about it, but when you SHOW it graphically I got it! Thank you very, very much!
What I find interesting is how many different ways you can interpret Relativity and get the same outcome. You could also show that as velocity increases, length contracts along the direction of motion.
As you accelerate, the apparent length shrinks so that the muon lives the same time, but the distance to Earth is shorter. Also, since length contractions is exponential, the faster you go, the more contracted the increase in distance the new velocity delivers. At c, the length is 0 so any increases in speed adds 0 more distance per time.
Maybe I'm looking at it differently, but lengths (distances) obviously don't change, whereas the time changes can easily be measured. I see what you're getting at, the apparent distance is shorter because your speed is greater, so it takes less time to get there. That, however, is not what is actually happening. Time is the variable, not distance.
@@briandbeaudin9166 You say "apparent" distance, implying there is a universal distance all can agree upon. However, in Relativity, the only things all observers can agree upon are the speed of light and cause/effect. Distance and time are observer dependent.
Agree with DJ_Force regarding distance & length being dependant on observer reference frame. Look-up "the ladder in the barn paradox" @@briandbeaudin9166
the wavelength contract i guess ? red and blue shift. i might be wrong
Finance and Data Analytics guy here, passionate about math and astrophysics just got the most clearest explanation of why we can't reach speed of light on a random Saturday at 2 AM. Thanks for dumbing it down for us, and your enthusiasm !!!
You just gain a subscriber.
Absolutely loved this video..u explained this to me so well in just 16 min..amazing
Now I understood man. It was so tough to wrap my head around it. Brilliant. Amazing work!
Best teacher we'll ever have
Cheers for mahesh
I am not a Math person and I can easily get lost in it but you just made this video very easy to understand the math here. Thank you and yes keep infinitely doing what you do👍🏼👍🏼👍🏼
I like your energy bro. You are taking things in such a good perspective that it can change the views of people on physics . ❤❤
bro, this was amazing. the question that I had since decades, the question that noone could answer, finally its before me. Thanks for this!! At every step I was asking "but what about that?" and you brought that exact same question and answered it beautifully. Salute to you sir.
Your home security is great
4:46 :vsauce starts playing
hi people , i am from brazil. its amazing how your " level" of problem is trying to understand this really complicated topic. i want you people to understand, the reason why america is such a great country is because there are people in the comments trying to explaing to a 9 years old daughter about relativity. THIS is the reason, you guys get curious about something and try to investigate. That is what makes your society way more advanced than 3rd world countrys. Here, people are proud of being ignorant about things..... congratulations to everyone who watched this video, i hope your life is full of blessing, please raise your children to be curious about the universe and ask questions. Never let your country become what is happening around the world.
You deserve a Nobel Peace price for this explanation. I have been listening to proclaimed scientists on UA-cam trying to explain this phenomenon and none comes close. You are a hero. Keep'em coming baby
The passion you put on the explanation... THIS GIVES ME GOOSEBUMPS.
Thank you for the awesome vídeo.
Best regards, from a viwer here in Brazil.
Well, this video is worth more than all Instagram Reels and TikToks together that I have ever watched in my life.
Who noticed "Don't be a jerk" 😂
Yay! :D
I don't know whether to feel smart because I finally understand special relativity, or stupid because I still don't understand the t-shirt.
@@DavidBairdSailing It's the formula for how acceleration changes per second, also called the "jerk" formula.
I was trying to work out what the derivative meant. Now I understand.
d3x/dt3. Include mass and you have the original Delta Force.
Finally! After all these years trying to understand this, one video, expertly and simply done and I get it. Thank you so much for this.
You are really making great videos. I would like to add a suggestion to you as a learner that please make more video on complex ideas of quantum mech and black hole physics.... classical physics(emt,str,gtr) are totally intitiutve but modern theories sometimes creates conflicts
Great video! You're very passionate explaining this stuff, and you made every step easy to understand to, i believe, everyone. You kind of broke down the idea that I had before which was somehow the object becoming heavier as it sped up, or something that is not very intuitive like that. BUT (it wouldn't be a UA-cam comment without a but...) I was really expectant, as a follow-up towards the end, of the explanation of why the ship can't reach the speed of light but from the perspective of the ship, since the time for the passengers inside the ship is the time proper. Right? They would just keep "feeling" (well, dead) an insane acceleration of 1000m/s/s instead of it starting to decrease more and more, right? Or would they start feeling at some point "hey we're accelerating at just 1g now"?
The intuition that I gained from your video left me with the idea that to those inside the ship, it can accelerate normally +1000/s every second until it reaches the speed of light without anything there making it harder and harder, or even stopping them from surpassing it, from the POV of the passengers. But their time would be moving "faster", so when they reached the speed of light, the universe would be long dead, since they took forever, but from their perspective it was just another second to add +1000m/s to the speed? I think I'm very wrong here so this gave me a bit of a sense of non-closure on the topic 😅
But I assume there's just another perspective of the same Physics and Math equally making something there equally infinite, or zero, and I love to know what is it and how to understand that in an intuitive way like what you did from an external perspective, as well!! Pleeeease follow-up video/short/comment whatever! I must know! x'D
Oh! I literally had the exact same question😂 Glad I'm not the only one wondering. There's bound to be an answer for it. Please do a follow up video!
@@gonadforsale Follow up coming!
Hi mahesh, i’ve wrote you this message on instagram but you didn’t saw it. So ill put it here.
Hello dear mahesh!
Im writing you from Israel. Im a physics student thats waiting to start his last year in the university towards getting my first degree in physics. Im sure you’ve heard about the war thats going on in here, and because of that the university keep on delaying the start of the semester, so i didn’t learn physics in the past 6 months :(. Thankfully, i’ve came across your great youtube videos, and even though i’ve already learned most of the topics that you are talking about, i’m having a great time watching them. It really makes me feel better in those tough days. So I just wanted to thank you personally, and tell you to keep up with those amazing videos. Thank you So much❤️
Wow, thanks a lot for sharing. Made my day. I am not active on Instagram, sorry :(
I remember in 2002 I went over this in physics 2 shortly after kinematics and had so much trouble with it. You made it so clear. Thanks for your help
“The mewing twin will age slower”
Love your video, would you please explain how the twin paradox is resolved? And why or why not accelaration is absolute
Yes yes, it's in the bucket list. I want to do the E mc square derivation first!
Great explanation and visuals. I wish I had these back in my Physics undergrad!
Same feeling here :)
I had already understood the topic, played that experience game that shows visually what time dilation would look like, understood the examples of being in the event horizon and looking like you froze while you're moving, and this still showed a whole new view on what practically would be the experience, like isolating other constant than what I'm used to isolating. Great video. After years of thinking you grasp something, there's always a new view on that to make you understand that something better. Thanks for the damn good work!
Hey mahesh as always great video but I have a question. If I was in the spaceship then time would pass normally for me. And now if I’m at 99.99% c and If I just became faster wouldn’t I reach c out of my perspective ? For others it would take endless time but for me it wouldn’t or ? I don’t see my mistake in here but there surely is. Because for someone traveling at for example 1/2c his time would have been normal for him. So 10 years for him but on earth 100 years. And now can’t I say yeah I reach c but for others that time dilation is so big that it is infinite for them?
I think you're right, but by the "time" you reach c, the universe (everything that isn't travelling at 'c') will be "dead", consumed, in a black hole, transformed into iron, or whatever the end looks like.
Also, the probability of you NOT hitting a grain of dust must be 0, so you'd be dead too because of that.
It kinda a head nut yes. I'm with you cause I thought the same. But you the passenger would still age slower cause you travel at almost luminar speed. Therefor the "real" time slows down indeed. For you too, cause your removing so fast. Imagine going earlier outside for work, you would probably arrive earlier on work then right? Since hypothetical time would get to a hold at direct lightspeed, making you either immortal, as long as you move that fast, kills you instantly cause your life will be over in seconds in a "natural" way or you outright freeze in time and Every move takes infinite time to make.
Let's say time slows down to 0 at lightspeed. That would mean that at 99 percent of ls the accelerating would take longer, like he said in the video. Time slows down ultimately for us,maybe without noticing, but we'd still be several centuries old when we arrive at our destination. The only question would be if we re dead or Alive. Let's say ls.travel is possible, would it instantly jump to the moment that we slow down (however that works) and arrive at the destination? Cause we weren't experiencing time, so we didn't had for time to pass. Tho for an observer it would take us for example 4,5 ish years to get to aloha centauri.
I should get to an end, my head smokes.
If a stationary person is seeing a moving person's clock move slower, then the moving person would see the stationary person's clock moving faster. But from the moving person's perspective, they themselves are stationary and also from the moving person's perspective, the stationary person is moving; so the moving person would see the stationary person's clock moving slower not faster. I never understood this part of special relativity. Could someone explain it?
Yeah!!! I keep trying to get this one, and I keep failing!
well you answered it yourself, now moving person is stationary from his perspective and stationary person is moving with the opposite vector 'c' and above explanation fits this scenario too, and hence it moves slower for both the person from their perspective as stationary. for more clarity please watch from 3:00
Im not a science guy but im curious to know why it matters what the speed of spaceship appears from outside. I mean, if it's goin at the speed of light why should the outside perspective matter?
For the spaceship itself time will tick slower, that's what he explained with the help of half life and muons example. So while approaching speed of light it will take infinite time/finite enegry OR finite time/infinite energy
Hands down the best explanation on the internet for this topic. Never been explained so simply yet so effectively.
A question I've always had but haven't the math to understand:
If two photons (call them Alpha and Beta) are sent out from Earth in opposite directions, each traveling at c. Where Alpha is represented as -c with respect to Earth and Beta is moving at +c with respect to Earth. We now change our referent from Earth to Alpha. Earth now holds a relative velocity of +c relative to Alpha, would Beta not then hold a relative velocity of +2c relative to Alpha?
How does this square with the speed limit of c? Does time dilation change the relative value of velocity such that the perceived speed of Earth from Alpha is
You can't do that. Light always travels at c, in all reference frames. This means that light itself does not have a valid reference frame (since there is no frame in which light is stationary).
If instead α and β were particles travelling very close, but not quite at, the speed of light, then you could use the "Velocity Addition Formula" to find out the the relative speed between them (which will always be less than the speed of light).
Fantastic explanation. Still a little confused though! From an observer's perspective the ship with constant thrust will take forever to attain c due to time dilation, but from the perspective of someone on the ship they do not experience time dilation so what prevents them attaining c after the required number of speed increments? What would someone on the ship perceive as happening?
Since any amount of time passage from their perspective now equals infinity for the rest of the universe, I suppose what they would experience is instantaneous end of the universe :)
How does this work for the observers on the space ship as it approaches C? The observers on the craft would still see light move at C and the ships particles would interact with eachother at C. So couldn't the observers on the ship reach C from their perspective? (Asuming you don't care the heat death is occurring outside your craft as near infinate time passes ouside the ship)
I was wondering this too. I suppose the explanation is that it takes infinite energy so it's just not possible. But if we ignore energy then when you reach the speed of light all time instantaneously happens outside of your space ship all at once and you would observe all of it in that very moment. It would just be a bright flash of light I guess. And then what? You could slow down but what happens, when you are outside of all time. You have gone beyond an infinite amount of time. It makes no sense, so luckily infinite energy is impossible to avoid that paradox.
@@asleepappeal so, if you reach the speed of light, you would theoretically generate infinite mass as well right? At the point of infinity, when your spaceship finally reaches the speed of light, it's infinite mass would literally suck in everything in the universe as the biggest supermassive black hole to ever exist and annihilate the universe. Theoretically. I think the concept of infinity in general just breaks everything
Also, what does proper time even mean. The universe does not have a preferred reference frame. The person, once he stopped acceleration, no longer is anything special. In his pov everything else is moving but him. So everything else is experiencing time dilation.
To answer your question tho, length contraction, the universe appears to become very short.
I never was good at physics but I totally understand your explanation…
Thx!
i’m not smart enough to understand this. lol
It’s not everyday that watching a UA-cam video makes me feel smarter! Thank you for this!
This was incredibly informative and insightful. You have a gift for explaining complex theories in simple ways.
It’s so refreshing to hear one of them teaching accepted science. I wish more of them would.