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What happens if Im accelerating and reach 60% the speed of light and at the same time an object is accelerating towards me in the opposite direction reaching close to the speed of light. Shouldn't I perceive the incoming object to be moving towards me faster than light? V1 + V2
@silverrahul I made a big mistake in the questions, I will remove my comments above and write the corrected questions here. (Question 1) There are three objects in space in a line: A ------ B ------ myself They are both moving in the opposite direction to myself in that line (so, to the left). Relative to myself, A's speed is 0.5c and B's speed is 0.9c. I start accelerating in the opposite direction these objects are moving (so, I accelerate to the right). At some point, my speed relative to A becomes 0.99c. This means our relative speed increased by 0.49c. If I assume Newtonian physics, my speed relative to B becomes 1.39c. But that can't happen, so it's not a simple addition - which is clear from the equations. What would be my speed relative to B? I'm sure it'd be something between 0.99c and c (exclusive), but it's not intuitive to me... (Question 2) Let's add an observer. A ------ B ------ myself ------------------------------- ------------------------------- ----------- C ---------------- Assume the same initial scenario as above and assume that I'm initially not moving relative to C. What would be my speed relative to C after I accelerated to the point where my speed became 0.99c relative to A? Since A is moving at 0.5c to the left, would C see me moving at 0.49c to the right? That's clearly wrong, so again, this is not a simple addition/subtraction. Even though I (myself) see A moving at 0.99c, C can't see me moving at "just" 0.49c, it must see me moving faster than that. This can be understood through length contraction, but it's hard to visualize.
Question: What is the time dilation from say a photon of lights perspective coming from the sun? You covered what it would look like as something is moving away but not something coming at you at the speed of light as well as constant acceleration. We say it takes a photon to go from the sun to the earth in ~500 seconds. There is no deceleration to take into account due to the photon hitting earth at the speed of light. Also, without doing more research, does our current speed of light (299,792,458 meteres per second) take into account the solar systems parabolic path through the galaxy as well as the path of the Galaxy's speed in relation to the universe and heaven forbid the universes speed of motion in relation to something else (hyperspace?)? Using the same light bouncing method from the photons perspective coming from the sun it takes a longer path than just a straight line from point A to point B (sun and earth). Does our current defined distance to the sun take into account all of these factors as well or is the Sun closer than we think because we did not take into account its motion relative to us? One more question. Gravity has an effect on the speed of light from what I gather from our current understandings told to me by people a lot smarter than myself. If light can not escape the gravity of a black hole than the speed at which light would be moving in relation to everything else would be skewed due to having to travel a longer distance if not completely halted and pulled back in the opposite direction toward the center of a black hole depending on how a black hole affects a photon. Either way if it is gravitational lensing or straight up decreasing the speed at which a photon moves does that not mean that any gravitational anomaly would have an effect on a photon? Does a photon travel slower in relation to us as it leaves the surface of the sun or for that matter travel a longer distance in the case of gravitational lensing. Then for a lack of better terms reach (100%) speed at the LaGrange point between us and the sun where gravity would be 0 and then pick up speed or travel less distance as it enters the gravitational field of the earth to go again for a lack of better terms (102%) Granted the Earth would not impart as much gravity as the sun or the sun as much as a black hole but gravity is not a constant. Because if this is the case then is the speed of light really a constant on a universal scale in relation to us? Last question: Hopefully I wont lose you here but have you heard Russ Humphries hypothesis on a young world using current physics understandings and different ideas being floated such as hyperspace and such and applying it to biblical text? Here is a link to one of his presentations that is on the laymen's level to attempt to explain his thoughts. If I can take what he put in this video at face value it would be able to explain how light from a galaxy currently described by scientists as 4.2 billion years away to only ~6k years using our current understanding of physics. If you have never heard of him could you watch this video and let me know your thoughts? ua-cam.com/video/loYE4-pSChc/v-deo.html
@@boukman3668 Depending on how close to the speed of light and how far away you are would you even see it? If you take into account the length contraction paradox coupled with it would need to be reflecting visable light off of the object moving toward you in order to see it. So you would only see it at a distance proportional to the distance away it is to its proportion of the speed of light. If it is traveling at you at 99% of the speed of light and you are traveling at 99% the speed of light you wont even see it until it basically runs into you.
@Mahesh_Shenoy Another thought experiment would be to take into account how long a transmission takes to go from earth to the Voyager probes taking into account the solar systems parobolic path in relation to the galaxy and the galaxy in relation to the universe. Because it would be the furthest man made object that we could use as a reference point of light not traveling in a straight line. I know NASA takes into account distance for transmission times but do they take into account the reletive motion of both the earth and probe in relation to the universe?
@@Mahesh_Shenoy Your are missing the point. The effects of Relativity are just apparent and not real. Relativity is an optical illusion. According to Relativity, two inertial moving observers will see each others space contract and time dilate. This is a complete contradiction and a physical impossibility if the effects are real. Objects and the passage of time can not be both small and large at the same time. The only possible explanation is that the observed effects are an optical illusion. Any theory based on Special Relativity, such as General Relativity, must also have the same problem. Hi my name is Dr William Walker and I am a PhD physicist and have been investigating this topic for 30 years. It has been known since the late 1700s by Simone LaPlace that nearfield Gravity is instantaneous by analyzing the stability of the orbits of the planets about the sun. This is actually predicted by General Relativity by analyzing the propagating fields generated by an oscillating mass. In addition, General Relativity predicts that in the farfield Gravity propagates at the speed of light. The farfield speed of gravity was recently confirmed by LIGO. Recently it has been shown that light behaves in the same way by using Maxwell's equations to analyze the propagating fields generated my an oscillating charge. For more information search: William Walker Superluminal. This was experimentally confirmed by measuring radio waves propagating between 2 antennas and separating the antennas from the nearfield to the farfield, which occurs about 1 wavelength from the source. This behavior of gravity and light occurs not only for the phase and group speed, but also the information speed. This instantaneous nature of light and gravity near the source and been kept from the public and is not commonly known. The reason is that it shows that both Special Relativity and General Relativity are wrong! It can be easily shown that Instantaneous nearfield light yields Galilean Relativity and farfield light yields Einstein Relativity. This is because in the nearfield, gamma=1since c= infinity, and in the farfield, gamma= the Relativistic gamma since c= farfield speed of light. Since time and space are real, they can not depend on the frequency of light used. This is because c=wavelength x frequency, and 1 wavelength = c/frequency defines the nearfield from the farfield. Consequently Relativity is an optical illusion. Objects moving near the speed of light appear to contract in length and time appears to slow down, but it is just what you see using farfield light. Using nearfield light you will see that the object has not contracted and time has not changed. For more information: Search William Walker Relativity. Since General Relativity is based on Special Relativity, General Relativity must also be an optical illusion. Spacetime is flat and gravity must be a propagating field. Researchers have shown that in the weak field limit, which is what we only observe, General Relativity reduces to Gravitoelectromagnetism, which shows gravity can be modeled as 4 Maxwell equations similar in form to those for electromagnetic fields, yielding Electric and Magnetic components of gravity. This theory explains all gravitational effects as well as the instantaneous nearfield and speed of light farfield propagating fields. So gravity is a propagating field that can finally be quantized enabling the unification of gravity and quantum mechanics. The current interpretation if quantum mechanics makes no sense, involving particles that are not real until measured, and in a fuzzy superposition of states. On the other hand, the Pilot Wave interpretation of Quantum Mechanics makes makes much more sense, which says particles are always real with real positions and velocities. The particles also interact with an energetic quantum field that permeates all of space, forming a pilot wave that guides the particle. This simpler explainatiin explains all known quantum phenomena. The only problem is that the Pilot Wave is known to interact instantaneously with the particle and all other particles, and this is completely incompatible with Relativity, but is compatible with Galilean Relativity. So due to the evidence presented here, this is no longer a problem, and elevates the Pilot Interpretation to our best explanation of Quantum Mechanics UA-cam presentation of above argument: ua-cam.com/video/sePdJ7vSQvQ/v-deo.html Paper it is based on: William D. Walker and Dag Stranneby, A New Interpretation of Relativity, 2023: vixra.org/abs/2309.0145
Absolutely fascinating, Mahesh! Each video in your special relativity playlist is helping me grasp the idea that our current physics theories aren't necessarily right or wrong; rather, we embrace and utilize them because they effectively describe and explain the phenomena occurring in the universe.
I like this idea. People always praise physics as if it's some sort of truth machine that churns out irrefutable objectivity. Whatever that means. In reality, physics is math done such that it's as close to our observations as possible. There's no such thing as "objective reality", we most likely aren't decoding anything. Just making human models. Still, one can't deny their elegance.
@@Mahesh_Shenoy A great way to visualise that is imagine holding out a bed sheet from all 4 corners, then putting a bowling ball in the middle. The funnel is like curved spacetime due to gravity. Imagine travelling in a straight line and going into the funnel, you either drop into the middle and crash into the bowling ball, or you end up going around and around it indefinitely, or if you go in fast enough, your straight path deviates slightly and then you escape it entirely
@@phillipjoyce8825No, this doesn't explain anything. When you put a ball on the sheet it creates a dent in which other balls fall. They fall because of gravity, so you are explaining gravity with gravity. As for an actual explanation: spacetime gets distorted around massive objects, but such a curved spacetime can only influence objects that are moving. If something is not moving, then it's not. If something is moving then it's moving in a straight path - which we don't see as straight because the spacetime is curved. So satellites orbiting the earth go straight through spacetime which is curved and that's why they go in circles. Understanding how gravity works on stationary objects is a bit more tricky. The thing is NOTHING IS STATIONARY. You always move through spacetime, so if you don't change your position, you travel through time (into the future). This is very important - space and time are different aspects of the same thing, spacetime. So if you for example sit in a couch right now, you don't move through space, you move through time. Now, because of the Earth, spacetime around you is curved - not space - spaceTIME. You travel through time in a straight path but because spacetime is curved you actually go off this path and you get redirected to space dimension. When a satellite go around earth it gets redirected from one space dimension to another and that's how it goes around. Now you go through time and get redirected in the same way, but to space dimension - specifically to the earth center of mass. So you travel through time but go off the course and you get pushed to the surface of the Earth. And yes, because of that your time also slows down. Time slows down near massive objects because some of the speed through time gets "used" to being pushed into the space dimension.
@@phillipjoyce8825 it feels a bit 2d like. I’d recommend SCIENCLICS video on time dilation. He provides a good framework of imagination for us to work with .
@@phillipjoyce8825but why did the bowling ball move in the middle,the four corners are anti gravity points without mass?,bad analogy,it uses gravity to explain gravity
Another way to think of it is Length contraction. As you fly in your spaceship and get close to light speed [c], it will appear to become shorter to outside observer. But also, for you inside the spaceship, you will see the Universe contract in your direction of motion. So for example if you are heading for another star 87 light-years away at 87% of c, it will seem like it's only 43.5 light years away for you. Instead of 100 years to go there, you will only count 50 with your onboard clock. And if you edge close to c, the distance will become infinitely small. In the end the whole 3D universe will be compressed to a 2D plane for you. Imagine that! To joke around a bit, if you could go over c then maybe you could burst out of this universe and enter a different kind of universe, where perhaps the lowest speed is c instead of the top speed there. OK OK this doesn't make as much sense, but, feel free to give your ideas on this.
I posted a comment before realizing this was a fairly old video. Maybe you'd have an answer? If the time aboard the ship is actually dilating, then my perception of objects outside the ship should appear to quicken in proportion to time aboard the ship slowing shouldn't it? If so, then the apparent relative acceleration of the object passing the window should still appear constant, right? I shouldn't perceive that length contraction. Unless time dilation doesn't affect perception, at which point I would feel like I was stuck in slow motion. Then again, since perception is dependent on electrical signals traveling through nerves and brain matter, and C is constant from all reference frames, depending on which way I was facing at near light speed, these signals would travel very slowly along some (forward facing relative to the ship's direction of travel) nerves and very quickly across other (reward facing) nerves, so who knows if my brain would even function correctly at that point.
@@CallidusVeloxI was thinking the same. If we were traveling toward an object at the speed of light, we might not be able to interpret what we were seeing but if we calculated our deceleration we could still travel to an object at the speed of light or faster and not crash into it. We could slow down to a speed we could interpret and still have reached the object at what we would expect having traveled at the speed of light
@@CallidusVelox ffs UA-cam deleted my reply.... Basically I said you don't feel in slow motion. The passage of time you experience never changes for you. You may see the universe accelerate though. For example, if you travel at near light speed towards a rotating star system, you would see it rotate faster.
@@Albtraum_TDDC That's what I'm inclined to believe, mostly because I've read too much science fiction, but how do we know? I guess we won't until and unless we subject a human to near light speeds, but how would the delay of energy traveling through (I believe he called them) motion carriers affect the brain? Like, if we had a skateboard with a lightbulb at the front and one at the back, both the same distance from a power source sitting in the exact center of the skateboard and we sped the board up to some appreciable fraction of C and then flipped the switch, then the light at the rear of the board should turn on before the light at the front, right? How would that same effect work on the electrical signals traveling through our brain? How would that in turn affect our perception? Would that result in our perception slowing to match the slowed motion of our surroundings, or would it just make a confused mess of the inner operations of the brain?
@@CallidusVelox motion carriers will not affect your brain because you're all in the same inertial frame of reference. You might appear weird for an observer on a different inertial frame of reference though. The only difference you'll see is on things in different inertial frames of reference. Like a pendulum inside your spaceship will keep working the same way to you. But if you're going over 99% of c towards a rotating planet, you'll see it rotating a lot faster than when you were stationary compared to it (same frame of reference).
Sir, Can you make a video on misconceptions about electricity I tried to understand the transfer of energy in wires from other channels but it was hard and some of those concepts are still quite weak.
@@Mahesh_ShenoySir, I watched all those videos and it helped me a lot, but I had watched Derek Muller's (a PhD physicist) video where he claims that electrons carrying potential energy around a complete conducting loop transferring their energy to the load is all FALSE.He explains that how actually energy is transferred through electromagnetic fields and electricity flowing in one isolated conducting wire can cause electric current in the nearby isolated conducting wire. 1st video where he discusses the main question: ua-cam.com/video/bHIhgxav9LY/v-deo.htmlsi=yqd0b_RLQ66aEKq2 2nd video where he performs the real experiment: ua-cam.com/video/oI_X2cMHNe0/v-deo.htmlsi=R44c_cECV0L3-t1O I had a hard time understanding these videos. Sir, what are your views on his claim and the videos.
@@snaatanraina 1st by Physics asylum and next Veretasium only these two ever did video about ur above statement (poynting vector energy flow) do watch the debate video between derek and electroboom
This is the first I’ve seen of your channel but if your other content is at all similar in content and quality then this has to be the best algorithm based recommendation I have ever received on UA-cam. Thank you!
Great job explaining a very difficult aspect of General Relativity that is hard to grasp without doing the math. You have a great gift at explaining things intuitively, your students are very lucky to have you as their teacher.
@@sendintheclowns7305 Seems like you have no arguments and just dumb belief. I can VERY WELL explain why I think he's wrong, but as you mentioned, I think you don't care about actual knowledge.
Thanks, it was great explanation, yet, it missed some important explanations like: - Why the speed of light is constant? - When the clock pointer moves in the direction of the movement it gets understandably slower, but why it does not go faster in the other direction? - Why can't we consider all the movements relative to the center of the universe and get rid of the whole relativity jargon? Or, can we? - What is the relation between relativity and Higgs Bosons? - Are you really saying space is changing, or only our perception of it? And that could mean for the center of the universe? - What is the relation between all of this and the energy preservation concept in a closed system? And what will happen if we discovered someday that our universe is not a closed system?
What is the center of the universe? There is no such thing or at least we don't know about it. People usually confused about the center because of the Big Bang theory - they imagine there should be a center of the Bang. But the truth is the universe expand like a balloon, from every point simultaneously. From our perspective we are the center of the universe.
- Nobody knows why natural constants are the way they are. We just know that they... well, are that way, as we can measure them. By "Speed of light" C, by the way, it's always speed of light in a vacuum. Light in a medium like air, water or glass may very much be measured with a speed different from C. - It sounds intuitive that it could go faster in the other direction, but; It is about the speed at which information, at best, can spread. And that's C. It does not matter in which direction the clock pointer moves, it will slow down from an outside observer's perspective as it is accelerated. - Where is the center of the Universe, and why should we accept it as a universal reference point? What makes this place better as a center than any other center, what gives it the privileged position? We have to assume that all Rules are the same everywhere, so the center of the Universe is not special, and depending on where in the universe you are, you would observe very different times depending on where you are. Imagine 2 stars going Supernova. Both are 2 Light-years away from you, so from your perspective they go off at the same time. Another observer that is 1 Light year away from Star A and 3 Light years away from Star B will disagree with you, as he observes something entirely different. And a 3rd observer sees it exactly the other way around. Who gets to claim what is real, and why should that reality be privileged above the others? That's the problem relativity gets rid of. The Formulas may seem scary, but the Theory of relativity made the Math in certain field of physics so much easier than everything they had before, and they were measurably accurate. - I pass that to someone who knows their way around quantum-stuff. - Spacetime is changing. It is a measurable fact. See Cassini; They flew Cassini around the solar system and send out signals to earth, the duration till arrival predictable... until they send a signal close by the sun. The Gravitational field of the sun made the duration longer, implying that gravitation bends spacetime. And it lined up perfectly with predictions of relativity. - I leave that to philosophers
I can answer 2 and 5. 2: because although the clock is pointing in the other direction the velocity of the ship is still going one way therefore although on the ship the hand of the clock appears to move to one direction it is actually going in the other (it isn't rotating the other way just moving, also the clock doesn't matter it is about all things such as you or me. when we move the same thing happens and so all of our processes slow down therefore we experience time differently). 5: no space isn't changing just our perception, also wdym the center of the universe
My 2 cents: - Why the speed of light is constant? This is an interesting question, but entirely different topic. I saw a video from this channel on it. - What is the relation between relativity and Higgs Bosons? I think because he said in another video that the fundamental forces between quarks have also a speed limit, if the atom is already moving the nuclear forces need longer to reach the quarks that are moving away. This should, I think, also apply to the Higgs Boson, that already is responsible for the mass, if it needs longer to travel, that could mean an increase in mass. But... we don't have a theory of everything yet. Zillions of scientists are working on it, but haven't worked it out. - Are you really saying space is changing, or only our perception of it? And that could mean for the center of the universe? I think he's saying space is actually changing, and I think he's WRONG. It must just be the perception. Imagine a planet the size of a light second. If you stand still, you see the front one second before seeing the back, which gives it depth. But if you're moving towards the planet at close to lightspeed, the time difference between the signals goes down to just a half second, and if you're moving away, the time difference increases to 2 seconds. So if you move closer, it should look contracted, if you move away, it should look elongated. The video guy says it's just contracted, but I have a hard time believing it.
Wow, I'm speechless. This is the second video of yours I've seen, and you just appeared out of nowhere on my UA-cam. I'm truly moved. Throughout my entire life, I've always been very critical of teachers' didactics, especially when it comes to their views on teaching and, above all, the search for the why of things, the real reason behind mathematics, physics, and everything else. And for the first time, I'm seeing a teacher explain things in such a fluid, passionate, and direct way, questions I've always had, questions that have been eating at me because they seemed like unanswered questions. No one wanted to discuss them or they didn't understand the question I was asking. Your teaching is truly exceptional, and I’m genuinely moved. I deeply admire you, even though I’ve only watched two of your videos. The passion for searching for the why of things is amazing. Congratulations, really!
I personally hated physics all my life , just becoz of tons of formulas and ridiculously long calculations , I'm 18 now and preparing for Neet ( a premedical entrance test in India ) and I do like the concepts of physics like we got Motion 1D and 2d , Newton's Laws of motions , waves etc . AND I MUST SAY I WATCHED 5 OF YOUR VIDEOS JUST BECAUSE HOW WONDERFUL THEY ARE , it's a piece of art really , and watching this motivated me to go study some physics for my upcoming test 😂 😅b, TYSM bhaiya ❤❤❤❤ , LOVE FROM INDIA
I've never seen this explained so plainly before. I still can't wrap my head around what happens when there are multiple ship's and a platform's perspectives to all take into account. Here is the scenario: Ship A is traveling at .75c. Ship B is traveling at .75c in exactly the inverse direction. Observer C is measuring the speed of both ships from a third location. How fast are the ships moving from one another's perspective, and how fast are they moving away from one another from any third perspective such as that of Observer C? If the ships sent a signal to one another using a means of communication that travels at the speed of light, when would it get from one ship to the other? If the ships had an entanglement based means of communication as well, and communicated to one another via both methods, and measured the difference in how quickly the messages arrived, what would the difference be? Because it still seems to me that there could be some kind of, lets call it "3 Roentgen", situation going on around the measurable vs calculable vs practical c given that all the math insists that ship A and B are traveling apart at...infinitely close to but not quite c. Yet if those ships stop after a year, and set up colonies, and someone builds a super telescope to view signs of the sister colony with, then surely they better know not to expect to see anything of the other colony just one year later from the founding of their colony. The sister colony is located 1.5 ly away, and was only founded a year ago. Well, except that we can prove that they could only have moved 1ly away from one another in 1 year. Shit. It appears to me to be knots all the way around once you consider the speed from those three different points of reference, and I've yet to hear it untangled in a way I could follow. It seems like Einstein's train didn't take into account the perspective of the lightning bolts, nor the possibility that they might try to compare notes with one another throughout the process, nor what happens after said note-comparing objects in such situations stop and cease to be subject to the kind of length contraction that occurs at meaningful fractions of c.
Thank you so much, you're an excellent teacher and this channel is the only one which finally breaks some mental blockers, and allows me to wrap my head around relativity
This is the first time I’ve actually understood WHY time passes slower for a moving object or person. I’ve seen the photon clock explanation before but never combined with the propagation of information through a body at the speed of light. Fantastic!
I have one question about the speed of light, but first, I would like to ask something about changing frames of reference. Imagine I stand up and start rotating around my own axis; could I change the frame of reference to assume that I'm standing still, and the universe is the one spinning around me? I know that rotation is a motion which involves acceleration, so this non-inertial motion could prevent this. If that's the case, then my question is answered right there. But if we can apply the change of frame of reference even in this situation, let's do it. In this case, I am not the one rotating, but everything else but me. This would mean that, from my frame of reference, a chair located 1m away from me would be describing a circular motion, drawing a 1m-radius circle around me, right? Now, let's consider something waaaaaay further from me, like a galaxy on the edge of the visible universe, millions of light-years away: This same galaxy would be doing a circular motion around me, drawing a circle with a radius of millions of light-years. Consider that it takes 1 second from me to turn around; from my frame of reference, that would mean said galaxy described a circular motion around me in the same 1 second, but if we try to calculate the circular path it took to do so in this single second, considering it's a circle with million light-years of radius, it surely would mean the galaxy moved faster than the speed of light, at least from my point of view. As I said earlier, a possible answer for this scenario is to understand that my circular motion isn't inertial, so such a change in the frame of reference is not allowed by special relativity. Is this the case?
In General Relativity you can define such a frame of reference. And it's fine to have some things move faster than c there, c is only a local limit in GR. In Special Relativity, since it's not an inertial frame of reference, it can't be described by a single frame going through time, instead you'll have to switch frame of reference at every moment, which makes that other object's "motion" not a real motion.
@@thedeemon Considering a motion is a change of the energy, your spinning motion is still a real motion in Special Relativity... However the only problem with a Special Relativity is that general energy balance of the open system is barely considered... So that is the reason why amount of energy required to reach C is stated as infinite, while in reality it is just being measured in a wrong manner.
Just came here to let Mahesh sir know , there's none who could have explained electronics better. I hated every diagram and explanation. It was a huge burden for me . Got through the chapter from your electronics lesson @khan academy. I just loved learning it and that was way more interesting. Pretty much all of your vedio lessons are well presented and easy to understand!!! 🙌🙌🙌🙌 thanks a lot sir !
That's very high quality content. Would love to see such a high quality explanation of the twin paradox: why only one of the twins gets old? Pls I didn't understand that even by watching a lot of other videos. By the way, I've clicked the subscribe button at first glance of this wonderful channel!
And it's not just a logically correct theory to explain it without contradiction; we have proof of time dilation. One of the twins will be old if the scenario were created in real life. It's like magic, but not just an illusion; it's a true fact of reality...
It's actually amazing how this guy is able to ask Einstein all these questions and get his answers even though Einstein has been dead for so many years already! Is he able to travel back through time? 😊
With all due respect to Mahesh, who is an excellent tutor, Einstein had already asked and answered all these questions himself which Mahesh asks. Mahesh is simply explaining to us the questions and answers that Einstein explored in an era without the internet.
Well, technically everything travels at the speed of light all the time. Mass at rest just happens to travel at the speed of light through time instead of space.
This is quickly becoming my favorite physics channel. Great work, Mahesh! It's 1am,I have to work tomorrow, and I just played a gig (3 hours of high energy rock), but what's this? An explanation of length contraction? Meh. I'll sleep when I'm dead. Bring it on!
Thank you so much for your videos. This is what i was looking for for years, truly. Intuitive understanding of science is really fundamental. If it possible, could you make some intuitive explanation of twin paradox?
What a brilliant video Mahesh!! Reignited the physics guys within me ( I am a medical doctor btw). Will save these videos for my duaghter once she is capable enough to understand these concepts. U earned a sub brother. Keep up the great work!!
Your videos are amazing, but I think you sometimes oversimplify them, you are not completely wrong but you have forgotten some parts, which does not discredit you, since your videos are quite useful when you are beginning to understand relativity, however here is my position, you have forgotten the addition of velocities, I hope you read this: Reasons why c cannot be reached. Observer inside the ship: The main reason is the relativistic addition of velocities, which means that as the ship approaches "c", the increases in its speed become smaller and smaller, regardless of the applied acceleration. In addition, the crew member experiences an effect related to changes in the reference frame as the ship accelerates. Although its speed continues to increase, the perception of the distances traveled is distorted. This is not the classic length contraction, which refers to the shortening of objects in the direction of movement, but a progressive reduction in the perception of distances to objects at rest as the ship changes its reference frame. When changing its reference frame due to acceleration, the distances to objects at rest appear to progressively shorten. This does not mean that the objects appear closer visually, but that the measured distance is smaller than it would be if this effect did not exist. The result of the combination of acceleration and distance perception is a smaller and smaller speed gain, as this reduction factor intensifies as the ship accelerates, counteracting the effect of acceleration. However, the above effect is based on the fact that speeds add up classically, but in turn if we take relativistic effects close to c, it doesn't make sense. The above effect doesn't take into account the compression of speeds, so it would be accelerating more and more to compensate for the compression and in fact it doesn't put a limit. An important point is how speeds are perceived from different reference frames. The perception of someone traveling at 0.1c relative to an object at rest (0c) is indistinguishable from the perception of someone going at 0.1c relative to a frame going at 99.9c. In other words, there is no significant difference in how they appear to each other, despite the large difference in absolute speeds. This implies that distances measured by previous frames do not shorten in an extreme way as one approaches "c", but decrease steadily. An important point is how velocities are perceived from different reference frames. The perception of someone traveling at 0.1c relative to an object at rest (0c) is indistinguishable from the perception of someone going at 0.1c relative to a frame going at 99.9c. In other words, there is no significant difference in how they appear to each other, despite the large difference in absolute velocities, therefore, the distances that previous frames measure do not appear to shorten more and more - in fact it should be an invariant contraction, but because it is the distance measured towards an object at rest and not in motion with the instantaneous-previous frame, that contraction decreases each time it approaches c. Now, the previous case is also incomplete because, although the reduction in distances no longer increases, we are forgetting that when changing reference frames, not only does our view of the distances measured by other frames shorten, but also time. So not only do we see that it is closer (it did not travel as much), but also that it took less time. The result is that basically both things cancel out and we see that the only effect present that affects the speed of these external objects is the relativistic sum of velocities. External observer: From the point of view of an external observer, even if the ship increases its speed, it will never be able to reach the speed of light due to the relativistic sum of velocities, which prevents it from reaching c. However, this is not the only thing that limits its progress. As the ship gets closer to c, time for it dilates significantly, which causes the acceleration to become even less effective, that is, to decrease with greater magnitude. The closer you get to c, the harder it is to speed up, not only because of relativistic velocity addition, but because time dilation slows down your acceleration even more. This ensures that, from the observer's perspective, the ship will never reach the speed of light. Summary: In both cases, there are one or two impediments that prevent you from reaching the speed of light: • Inside the ship: relativistic velocity addition makes your speed appear to plateau and you can never reach "c." • Outside the ship: time dilation and relativistic velocity addition cause any further acceleration to be diminished as the ship approaches "c." As I said before, thank you for the quality of the videos you provide us. I forgive you for the mistake, because you always help me understand things.
But Mahesh, can Einstein tell me why my head now hurts after watching this video? Honestly I love the videos on this subject, they have been a great learning experience.
As I'm sitting here watching this, I'm realizing how much thought went into the visuals of Star Trek like when a ship goes in or comes out of warp...at least the later Treks. I guessing the original might not have been able to do those effects even if they were aware or wanted to. Specifically referring to length contraction here.
Thanks, you just answered a question I have been asking myself for years. I always saw the speed of light as a number, and why can we travel faster than sound but not light. Your graphic explanation of time dealation was like a switch turning on.
I have a question, its probably something i didnt get on the video, but imagine being the crew of the ship, it starts at 0km/s and its accelarating (1000km/s)/s, and its traveling through that cosmic plataform. Couldnt the crew use the internal clock of the ship to calculate how much time it takes to reach the speed of light and then when they hit it, print the timestamp and then print again one second later? When they desaccelerate to see where they printed the stamps woudnt it be at one light second apart? (slightly more if you count that they are still accelerating during the stamping) That being the proof that they traveled at the speed or even past the speed of light? The internal clock of the ship still works normally for the shipcrew, and their perceptions on whats going outside wouldnt matter.
You are one hell of a teacher. I wish I had you as a teacher in school, 45 years ago. I learn things now that I have wondered for a loooooooooong time :)
Thanks , your visualization gives a easier way to understand the concept , But I think one thing we still misses , what about color ? , Doppler effect ?
This is great stuff. I have felt that after reading enough books, I had about a 99% grasp on the concepts of relativity, but every time I read a new book or see a new video that explains it a slightly different way, I gain a little better "intuitive" understanding of it, like adding a decimal point so I now have a 99.9% grasp of relativity - but just like the speed of light - I never have a 100% grasp of relativity. 😂 Here's my request - because I like your style so much and I wonder how you might add to the intuition of something I have struggled to understand: Can you make a video discussing the chapter "The Frozen River" from Brian Greene's book "The Fabric of the Cosmos". I have read "The Elegant Universe" and "The Fabric of the Cosmos" about...I don't know...20 times...trying to grasp many of the thing he writes, but in "The Frozen River", the idea of all of spacetime existing simultaneously and that being so logically demonstrable by examining the reference frame of a very distant alien moving towards us or away from us...well, this concept has haunted me...because unlike quantum physics, which is so intangible, relativity feels intuitive to me, and so the ideas expressed in "The Frozen River" seem to very logically 'prove' that there is no past, present, or future, but only 'all of spacetime'. But anytime I say that out loud to myself, my mind implodes and I realize that I understand nothing at all.
And, as the contraction continues, more and more of the visual universe will compress as well; the closer you get to the speed of light relative to what you're seeing, the more of the universe will suddenly be visible - at least as what you're seeing is relative to you in the spaceship. Something moving away from you while you move sideways will appear differently than something moving towards you while you move sideways, for example. It's mindblowing how much craziness would happen in a scene with many ships moving near the speed of light in different directions relative to each other. And then it becomes clear how insane reality gets when you peer at the edge of a black hole......
This is the second time (I have found) a random (highly intelligent) person has explained a complicated issue in a way that is easily grasped. The other was on the subject of 'modes' in music theory. Some people just have this gift.
This was such a great video. It squarely addressed my biggest misunderstandings and misconceptions about special relativity. This video should get pinned to the top of all special relativity and faster than light videos on UA-cam. Great work. EDIT: I look forward to your upcoming video on the twin paradox which still conflates me.
Few Questions I got 1. If we see the ship is contracting, getting squished, won't the distance between the atoms reduce too? that means the c wont have to travel longer distances as we saw in first video? 2. When ship is moving, we saw each other being contracted, but who's actually being contracting and who's contraction is apparent, earth, platform, us or the ship? 3. From our reference frame, we saw that light had to travel more distance between each atom as a consequence of constat c, so shouldn't we see the ship being stretched instead of being squished? Please let me know what am I missing 🥺 Because if I'm within the ship, I see that distance between the plates of clock remains same, the distance between atoms of my ship remains same, so light should travel at normal time and not the dilated time. The only thing here explaining why we cannot reach c within the ship is that the entire space around us is squished, it's like there no space left for us to travel any faster. And If we do indeed reach c, all the dimensions of space has became zero from the length contraction equation, as if we aren't even in a space at all
Exactly, from the spaceship point of view, the rest of the universe is contracting, squished, thats why a spaceship that goes beyond 99.9% the speed of light can reach the edge of the universe in a few years of spaceship time, but the rest of the universe and earth will have aged billions of years.
You're confused because, contrary to this video premise, you can't really get intuitive understanding of reality explained through mathematical (geometric) model as if it was its direct representation (ignoring simplifications and hiding some important assumptions). Let's start with Space-time - It's a specific type of medium (field), which unlike it was initially assumed (aether) seemes to be moving flawlessly thrugh us when we're in motion. We "detected" it by observing time dilation, which was earlier deduced (by Lorentz) together with length contraction as a reasonable explanation of Michelson-Morley experiment results. Speed of light (causality) is constant... but only in space-time. However, arbitrary chosen frame of reference (like Earth or some spacaship) will always MEASURE the same speed, because of 3 things: 1) Time dilation 2) Length contraction 3) The fact that we cannot measure it any other way than bouncing photons back and forth (2-way speed of light). Relative to us speed of light is not constant - it's just an assumed simplification. Look again at the path in that light clock and try to synchronize it with perpendicular one (in direction of motion) - you should see what's going on. Now answers to your questions are just a consequence of what was stated above: 1. The only distance that matters is how much space-time your frame has traveled. 2. Each frame moving thorugh space-time is contracted, but without making assumptions you cannot determine how each frame is moving. Realtivity allows you to build coordinate system as if your perspective was absolute - that's why it's so useful. Even when you can feel acceleration, you can't be sure that perpendicular axis would eliminate space contraction. You probably started while moving with constant velocity in some random direction and that wouldn't change (in flat space). 3. Moving object would (have to) be squished physically, and aproached one geometrically - light from (image of) its distant part will reach us sooner.
@@CodeShudder Thank you for the clear and insightful explanation! Your breakdown of these complex concepts in relativity really helped enhance my understanding. I'll take some time to reflect on these points and explore them further to deepen my grasp of the subject.
@@piyush1365 I should warn you that this is not an orthodox way of explaining relativity. As I said, physicists focus on explaining equations, and the physical reality is scattered like missing puzzle pieces behind abstractions. The first of those pieces for me was @veritasium video on "Why no one has measured speed of light", but the only channel I know of with this approach to the subject as a whole is @dialectphilosophy
Hi Mahesh, This question will really challenge you. You are saying that in a spaceship approaching the speed of light from the Earth's perspective, the acceleration will gradually slow down due to the slowing down of the progress of electromagnetic waves due to time dilation and the spaceship will never reach the speed of light. However, on the other hand, when viewed from the Earth's perspective, the spaceship's length will decrease in the direction it accelerates. Therefore, the distance that electromagnetic waves must travel between atoms will be reduced to almost zero. So compared to Earth, time will almost stop, but the size of the spaceship will also decrease to almost zero. In this case, why is an interpretation made only by taking time dilation into account and it is predicted that the progress of electromagnetic waves between atoms will gradually slow down? As a result, both time and distance are multiplied by the Lorentz Factor and time becomes shorter.
Was really fascinated watching your recent videos.. Looking at your views while backtracking, gotta say you have come a long way sir... And your videos are really good too.. Love the way you explain stuff with great passion.. Keep it up
Thought of two things just now. The lenght of object, approaching C is constrained from our perspective (up to a material point I believe). It's mass is increasing (up to infinity, if I understand correctly). Making this object effectively a black hole, from our perspective. And making it cause a real impact to us, because of gravity, forcing us to fall onto it. And as we begin falling, I mean as we start to accelerate towards it, it makes relative acceleration between us and the object less than before we start moving. It thrilling relation.
I think this is the best explanation I have heard about this. I don't know much about relativity, but can someone explain why the speed of light is said to be constant? For example, if you were on a ship going in one direction at 70% of the speed of light and saw another ship going in the opposite direction at the same speed, wouldn't that ship appear to be going at 140% the speed of light?
Mahesh, you honestly did a very good job, one of the best explanations of relativity I have heard. But there is a big problem. For this to be correct there would have to be a constant point of reference in the universe, e.g. a reference frame that is not moving relative to the others. But everything is moving, no one can say which frame of reference is still compared to the other. Consequently time dilation would cancel out when the point of reference became the same or said another way, is a function of the observer. If you change the observer’s frame of reference you change his perception of which time is dilated.
Hi Mahesh, I recent discovered your channel and I find your vidoes very intuitive as you say it. Could you please now add the concept of gravity in relativity to explain the concept intuitively? ❤
Theres a fundamental understanding some people are still not getting and is not quite addressed in this video despite it being very accurate. This is all about the "speed" of light, but velocity in propoportion to space and time is locked in people's mind with a newtonion physics mindset. The video addresses the time experience for both observers, and it addresses the length contraction effect for the ship travelers as to why that time dialation doesn't ruin their perspective entirely. It does not directly address the perpective of the ship traveling TOWARDS an object and how they see space/time in reference to the approaching object. It's true that from earth, as that ship accelerates at constant rate, it would appear from the earth that it slows down as it gradually approaches the speed of light. It's true that from the ships perspective, length contraction would distort what earth looks like assuming they could somehow watch it accelerate away from them. Its true that at no point will that ship travel faster than the speed of light from the ship or the earth's perspective. However, people get hung up on that concept that you can't travel faster than light and they want to invent hypothetical travel methods of FTL or worm holes / etc. People still assume that if you are on a ship that only manages to go 99% the speed of light but you want to travel to a distant planet 1000 light years away, you will need to enter hypersleep since it will take 1010 years to get there. But its important to understand what the ship experiences. Say a friend left earth at about 299.5km/s (light speed is about 299.79km/s) then it would indeed take 1001 years to get to the planet and earth would be very different. But your friend does not need to travel faster than light to get there in his lifetime. He would have only experienced about 45 years before arriving on the planet. Due to length contraction, upon leaving earth at that velocity, space would not be the same to him as it is to somoene on earth. The planet would immediately look like its only 0.045 light years awat, not 1000. To change constant velocity to acceleration to be a little more realistic, lets say they left earth's atmosphere at 15m/s^2 and could sustain that level of acceleration indefinitely. The coordinate rate the traveler experiences would end up becomming "faster" than light without violating physics, due to length contraction changing the apparent distance of the object to the traveler at the same time the traveler is increasing their speed towards the object. The visual experience is still limited by light as it could never "look" like the light of that object is coming at you faster than light. However, the traveler will fly past the planet at absolutely insane speeds after little more than 5 years of accelerating at that survivable rate. Long story short, you do not need to go faster than light to essentially travel many light years in a fraction of years. If you could travel at 99.99 repeating% of light speed, and live, it would appear from your perspective that any distance traveled was practically instant.
Hi. Will you make videos about general relativity too? I really hope so. General relativity is something I never understood, but I am very confident you could make us understand. Congratulations for these amazing videos.
Hey, great work Mahesh, but can you also tell us why time dilates because of gravity? Like why it takes so long for an object to fall into a blackhole to an outsider?
Amazing channel, you have such a great way of explaining this complex subject matter. So glad I found your channel. What did you make of the Interstellar movie? Did you like how they addressed time dilation?
Mahesh, most boats have navigation lights red-right, green-left, white-rear… we can’t accelerate past c, but we could accelerate 2 ships to 3/4 c in opposite directions approaching each other… what happens to the lights as they approach/accelerate do they change color!? When the ships pass each other, would there be a flash (like a sonic boom)? Once they pass they become “invisible” to each other… would they compress each other/ could you take a picture at the moment they passed, or would the compression make them invisible to each other before they passed… if one ship slowed down after passing, the both ships would reappear?! Would the reappearing ships have “normal” color lights!!?
I have watched few videos of yours, and i'm fascinated by your effort to make regular minds understand high lvl physics by an intuitive way. I wonder: do you think the secrest of the world can be teach/learn this way? I have a bad feeling that our science reached a point where human intelligence can't keep up with such complicated theories, like there was a 'barrier' of knowledge for us... Maybe AI will break this barrier, I don't know, but you make me belive again. Well done, you are a Real Teacher
Wow, I just found this channel and am amazed that I can understand physics when you describe it here more than I have ever before. I am curious, maybe a question you have already answered, if you look at the spaceship, that is travelling very close to the speed of light, from inside where an object's magnetic forces are not distorted and accelerated that object, would that object then be traveling closer to the speed of light, or because it started at 0, would the same amount of effort to get to the speed of the spaceship be required to move it.
It is known that when we need to multiply two scalar quantities, we use the algebraic method (e.g. 3m × 5kg = 15 kg-m). However, when we study about vector quantity we realise that we have two different ways to multiply vectors which give two different answers. Why is there a need of second way? If there are multiple ways, then why only two, not 3 or 4? Explain in detail please sir.
I have a few questions that I’d appreciate someone answering :) If the ship were to decelerate and come to a stop, where would it be in space and how far away from where it started Now that both the observer and the spaceship are at similar relative speeds, how long has passed for both the person in the ship and the observer
I have another question. What if we go back to time dilation. Two observers are moving at a relative speed to each other. Both will measure the other at motion and themselves at rest. That means both will measure the other to be moving more slowly through time. That means both will measure themselves to be older after a set amount of time. This makes perfect sense in relativity, but what would I measure if I then accelerate to match the other observer's velocity? If we both stay older than each other, a contradiction arises. So what happens when I accelerate to the other observer's velocity and who would be older? I heard on quora that this requires some very advanced math, but if anyone could explain this to me even though I'm probably not on that level yet, I would be so grateful. The rundown of what I understand is this: The symmetry somehow breaks when one of the observers accelerates to the other's speed. I want to know how it breaks. What would either of them measure?
I think what everyone wanted to see was what it would look like from the point of view of someone on the ship who is looking out the front windows (ie, in the direction of travel). Every scifi show set in space has their own version of the starfield effect - how close were they ? What would it really look like to accelerate towards a high percentage of c, while facing the centre of the milky way ?
1. If electron flow is at the speed of light, electrons must be massless or pure energy? Or is electron flow just not at the speed of light? 2. If electron flow is at the speed of light, how can I accelerate the electron flow without infinite energy?
The thing I dont get is, what is a resting state? What is resting in the universe? Wasn't movement supposed to be relative to objetcs? Or is there an objective frame of reference in space?
While length contraction is a very real effect, it wouldn't be quite as visible to a relativistic observer as one might think: light from different parts of an object arrives at different times (light from further parts of the object arrives later), and light from the back of an object that would normally be blocked can end up reaching the observer when the object is in motion (while light from the front that would normally reach the observer can be blocked). As a result, a relativistic object appears to have rotated, and for a sphere, this ends up cancelling out the length contraction, so that while the sphere *is* length contracted, you'd still see a circular outline at any speed (but would see a different side than you would at rest). The event is known as Terrell rotation.
10 місяців тому
I do have some questions left. I do not dare doubt Einstein, but I do like to challenge him. I have no knowledge about the theory, only my real interest. 1) While we cannot see the ship move while near, at or above (which cannot be) the speed of light, we have a reference frame of our starting point and where we want to be. Then even if we did not SEE ourselves moving, we actually did right? So if we pushed ourselves past the speed of light and then slowed down again, shouldn't all the parts (atoms, subatoms, largers or smallers bits) still be there and see ourselves at the destination, faster then light reaches us? (then we could see ourselves coming 😀) 2) When even our Universe is turning at VERY high speeds, isn't our own reference frame wrong to begin with? Our at-rest state. Who's to say we aren't beyond light speed already? Since our universe could be the ship we are inside of. 3) Particles only slow down when colliding with other stuff right? Gravity, other mass or forces etc. So if en engine is accelerating and will keep doing so, it WILL go beyond light speed until it stops pushing. The question will be how much time 'outside' will pass. If the universe wouldn't end, it could take a googolplex (yeah, that's a real word) to reach >100% of the light speed right? I think the real problem is that we cannot calculate large enough numbers or computing power to calculate the time needed 'outside' to 'see' something reach light speed. There is still no evidence (from what I gather, DO read on!) of a REAL barrier that stops something from going to light speed, only that it will take such a large amount of time we cannot calculate it (yet). Something like the number Pi. Maybe Pi is infinite, maybe it actually has an end. There is one certainty, we will not find out ourselves.
Issue would be external light being blue shifter (looking forward) or read shifted (looking behind). forward looking Visible light would be shifted into x-rays, and looking behind, visible light would be red shifted into radio bands.
Wonderful video Mahesh, thank you! In previous videos you gave a very intuitive explanation for time dilation by showing that information transfer takes longer in a photon clock when it's traveling horizontally. Is there a similarly intuitive explanation for length contraction that relies on the physical properties / geometries of the system?
Brilliant explanation as was the last. I still dont quite understand it all but I understand more. Love that youtube presented your channel to me. Here is a comment so Algo the algorithm may help you grow
So, if you are travelling to a star 99.9 light years away from Earth and travelling at 99.9% of the speed of light. The dilation factor is 22. So from an earth observer it would take 100 years to reach the star. How much time would pass for the person on the ship? 100 years/22 or approximately 4.55 years? Or does the length change make this also 100 years?
The answer is actually much more simple than that. A photon is energy. An electron is an energy carrier. There's a maximum amount of energy an electron can carry. An energized atom cannot travel faster with energy than the energy can travel on its own. Its a simple way to ensure that the speed of atoms are capped. Lets imagine that we can maximize the energy an atom is allowed to contain, then the mere fact that the energy now has a mass to propel would always make the atom with the mass, slower than the energy without the mass. It's like finding the maximum speed an explosion of 1 liter of fuel can propel a golf ball. Then trying to make that same speed with a bigger pool ball. There's also something deeper and more fundamental going on here... specifically to do with photons, energy and light.
You will and should get billion views and subscribers. I could never met Einstein but I feel like I could understand Einstein through your explanations.
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What happens if Im accelerating and reach 60% the speed of light and at the same time an object is accelerating towards me in the opposite direction reaching close to the speed of light. Shouldn't I perceive the incoming object to be moving towards me faster than light? V1 + V2
@silverrahul I made a big mistake in the questions, I will remove my comments above and write the corrected questions here.
(Question 1) There are three objects in space in a line: A ------ B ------ myself
They are both moving in the opposite direction to myself in that line (so, to the left). Relative to myself, A's speed is 0.5c and B's speed is 0.9c.
I start accelerating in the opposite direction these objects are moving (so, I accelerate to the right). At some point, my speed relative to A becomes 0.99c. This means our relative speed increased by 0.49c. If I assume Newtonian physics, my speed relative to B becomes 1.39c. But that can't happen, so it's not a simple addition - which is clear from the equations. What would be my speed relative to B? I'm sure it'd be something between 0.99c and c (exclusive), but it's not intuitive to me...
(Question 2) Let's add an observer.
A ------ B ------ myself
-------------------------------
-------------------------------
----------- C ----------------
Assume the same initial scenario as above and assume that I'm initially not moving relative to C. What would be my speed relative to C after I accelerated to the point where my speed became 0.99c relative to A? Since A is moving at 0.5c to the left, would C see me moving at 0.49c to the right? That's clearly wrong, so again, this is not a simple addition/subtraction. Even though I (myself) see A moving at 0.99c, C can't see me moving at "just" 0.49c, it must see me moving faster than that. This can be understood through length contraction, but it's hard to visualize.
Question: What is the time dilation from say a photon of lights perspective coming from the sun? You covered what it would look like as something is moving away but not something coming at you at the speed of light as well as constant acceleration. We say it takes a photon to go from the sun to the earth in ~500 seconds. There is no deceleration to take into account due to the photon hitting earth at the speed of light.
Also, without doing more research, does our current speed of light (299,792,458 meteres per second) take into account the solar systems parabolic path through the galaxy as well as the path of the Galaxy's speed in relation to the universe and heaven forbid the universes speed of motion in relation to something else (hyperspace?)? Using the same light bouncing method from the photons perspective coming from the sun it takes a longer path than just a straight line from point A to point B (sun and earth). Does our current defined distance to the sun take into account all of these factors as well or is the Sun closer than we think because we did not take into account its motion relative to us?
One more question. Gravity has an effect on the speed of light from what I gather from our current understandings told to me by people a lot smarter than myself. If light can not escape the gravity of a black hole than the speed at which light would be moving in relation to everything else would be skewed due to having to travel a longer distance if not completely halted and pulled back in the opposite direction toward the center of a black hole depending on how a black hole affects a photon. Either way if it is gravitational lensing or straight up decreasing the speed at which a photon moves does that not mean that any gravitational anomaly would have an effect on a photon? Does a photon travel slower in relation to us as it leaves the surface of the sun or for that matter travel a longer distance in the case of gravitational lensing. Then for a lack of better terms reach (100%) speed at the LaGrange point between us and the sun where gravity would be 0 and then pick up speed or travel less distance as it enters the gravitational field of the earth to go again for a lack of better terms (102%) Granted the Earth would not impart as much gravity as the sun or the sun as much as a black hole but gravity is not a constant. Because if this is the case then is the speed of light really a constant on a universal scale in relation to us?
Last question: Hopefully I wont lose you here but have you heard Russ Humphries hypothesis on a young world using current physics understandings and different ideas being floated such as hyperspace and such and applying it to biblical text? Here is a link to one of his presentations that is on the laymen's level to attempt to explain his thoughts. If I can take what he put in this video at face value it would be able to explain how light from a galaxy currently described by scientists as 4.2 billion years away to only ~6k years using our current understanding of physics. If you have never heard of him could you watch this video and let me know your thoughts? ua-cam.com/video/loYE4-pSChc/v-deo.html
@@boukman3668 Depending on how close to the speed of light and how far away you are would you even see it? If you take into account the length contraction paradox coupled with it would need to be reflecting visable light off of the object moving toward you in order to see it. So you would only see it at a distance proportional to the distance away it is to its proportion of the speed of light. If it is traveling at you at 99% of the speed of light and you are traveling at 99% the speed of light you wont even see it until it basically runs into you.
@Mahesh_Shenoy Another thought experiment would be to take into account how long a transmission takes to go from earth to the Voyager probes taking into account the solar systems parobolic path in relation to the galaxy and the galaxy in relation to the universe. Because it would be the furthest man made object that we could use as a reference point of light not traveling in a straight line. I know NASA takes into account distance for transmission times but do they take into account the reletive motion of both the earth and probe in relation to the universe?
You are literally expanding the frontiers of us viewers’ knowledge with such concise yet intuitive explanations. You have my utmost respect.
Wow, awesome to hear that :)
@@Mahesh_Shenoy Your are missing the point. The effects of Relativity are just apparent and not real. Relativity is an optical illusion. According to Relativity, two inertial moving observers will see each others space contract and time dilate. This is a complete contradiction and a physical impossibility if the effects are real. Objects and the passage of time can not be both small and large at the same time. The only possible explanation is that the observed effects are an optical illusion. Any theory based on Special Relativity, such as General Relativity, must also have the same problem.
Hi my name is Dr William Walker and I am a PhD physicist and have been investigating this topic for 30 years. It has been known since the late 1700s by Simone LaPlace that nearfield Gravity is instantaneous by analyzing the stability of the orbits of the planets about the sun. This is actually predicted by General Relativity by analyzing the propagating fields generated by an oscillating mass. In addition, General Relativity predicts that in the farfield Gravity propagates at the speed of light. The farfield speed of gravity was recently confirmed by LIGO.
Recently it has been shown that light behaves in the same way by using Maxwell's equations to analyze the propagating fields generated my an oscillating charge. For more information search: William Walker Superluminal. This was experimentally confirmed by measuring radio waves propagating between 2 antennas and separating the antennas from the nearfield to the farfield, which occurs about 1 wavelength from the source. This behavior of gravity and light occurs not only for the phase and group speed, but also the information speed.
This instantaneous nature of light and gravity near the source and been kept from the public and is not commonly known. The reason is that it shows that both Special Relativity and General Relativity are wrong! It can be easily shown that Instantaneous nearfield light yields Galilean Relativity and farfield light yields Einstein Relativity. This is because in the nearfield, gamma=1since c= infinity, and in the farfield, gamma= the Relativistic gamma since c= farfield speed of light. Since time and space are real, they can not depend on the frequency of light used. This is because c=wavelength x frequency, and 1 wavelength = c/frequency defines the nearfield from the farfield. Consequently Relativity is an optical illusion. Objects moving near the speed of light appear to contract in length and time appears to slow down, but it is just what you see using farfield light. Using nearfield light you will see that the object has not contracted and time has not changed. For more information: Search William Walker Relativity.
Since General Relativity is based on Special Relativity, General Relativity must also be an optical illusion. Spacetime is flat and gravity must be a propagating field. Researchers have shown that in the weak field limit, which is what we only observe, General Relativity reduces to Gravitoelectromagnetism, which shows gravity can be modeled as 4 Maxwell equations similar in form to those for electromagnetic fields, yielding Electric and Magnetic components of gravity. This theory explains all gravitational effects as well as the instantaneous nearfield and speed of light farfield propagating fields.
So gravity is a propagating field that can finally be quantized enabling the unification of gravity and quantum mechanics. The current interpretation if quantum mechanics makes no sense, involving particles that are not real until measured, and in a fuzzy superposition of states. On the other hand, the Pilot Wave interpretation of Quantum Mechanics makes makes much more sense, which says particles are always real with real positions and velocities. The particles also interact with an energetic quantum field that permeates all of space, forming a pilot wave that guides the particle. This simpler explainatiin explains all known quantum phenomena. The only problem is that the Pilot Wave is known to interact instantaneously with the particle and all other particles, and this is completely incompatible with Relativity, but is compatible with Galilean Relativity. So due to the evidence presented here, this is no longer a problem, and elevates the Pilot Interpretation to our best explanation of Quantum Mechanics
UA-cam presentation of above argument:
ua-cam.com/video/sePdJ7vSQvQ/v-deo.html
Paper it is based on: William D. Walker and Dag Stranneby, A New Interpretation of Relativity, 2023:
vixra.org/abs/2309.0145
And if he's wrong? Then it's misinformation. I think that he indeed is wrong.
Mahesh you are inspiring young people while at the same time re-educating older folks. Perfect.
That's super awesome to hear :)
And if he's wrong? Then it's misinformation. I think that he indeed is wrong.
I love the way you are able to use your humor and conversational style to make these advanced topics more understandable and accessible.
Absolutely fascinating, Mahesh!
Each video in your special relativity playlist is helping me grasp the idea that our current physics theories aren't necessarily right or wrong; rather, we embrace and utilize them because they effectively describe and explain the phenomena occurring in the universe.
I like this idea. People always praise physics as if it's some sort of truth machine that churns out irrefutable objectivity. Whatever that means. In reality, physics is math done such that it's as close to our observations as possible. There's no such thing as "objective reality", we most likely aren't decoding anything. Just making human models. Still, one can't deny their elegance.
If you can find a way to show how curved spacetime produces gravity, in an intuitive way, that would be really great.
Need to learn more general relativity for that. Added to the list, though :)
@@Mahesh_Shenoy A great way to visualise that is imagine holding out a bed sheet from all 4 corners, then putting a bowling ball in the middle. The funnel is like curved spacetime due to gravity. Imagine travelling in a straight line and going into the funnel, you either drop into the middle and crash into the bowling ball, or you end up going around and around it indefinitely, or if you go in fast enough, your straight path deviates slightly and then you escape it entirely
@@phillipjoyce8825No, this doesn't explain anything. When you put a ball on the sheet it creates a dent in which other balls fall. They fall because of gravity, so you are explaining gravity with gravity.
As for an actual explanation: spacetime gets distorted around massive objects, but such a curved spacetime can only influence objects that are moving. If something is not moving, then it's not. If something is moving then it's moving in a straight path - which we don't see as straight because the spacetime is curved. So satellites orbiting the earth go straight through spacetime which is curved and that's why they go in circles.
Understanding how gravity works on stationary objects is a bit more tricky. The thing is NOTHING IS STATIONARY. You always move through spacetime, so if you don't change your position, you travel through time (into the future). This is very important - space and time are different aspects of the same thing, spacetime. So if you for example sit in a couch right now, you don't move through space, you move through time. Now, because of the Earth, spacetime around you is curved - not space - spaceTIME. You travel through time in a straight path but because spacetime is curved you actually go off this path and you get redirected to space dimension.
When a satellite go around earth it gets redirected from one space dimension to another and that's how it goes around. Now you go through time and get redirected in the same way, but to space dimension - specifically to the earth center of mass. So you travel through time but go off the course and you get pushed to the surface of the Earth.
And yes, because of that your time also slows down. Time slows down near massive objects because some of the speed through time gets "used" to being pushed into the space dimension.
@@phillipjoyce8825 it feels a bit 2d like. I’d recommend SCIENCLICS video on time dilation. He provides a good framework of imagination for us to work with .
@@phillipjoyce8825but why did the bowling ball move in the middle,the four corners are anti gravity points without mass?,bad analogy,it uses gravity to explain gravity
Another way to think of it is Length contraction. As you fly in your spaceship and get close to light speed [c], it will appear to become shorter to outside observer.
But also, for you inside the spaceship, you will see the Universe contract in your direction of motion. So for example if you are heading for another star 87 light-years away at 87% of c, it will seem like it's only 43.5 light years away for you. Instead of 100 years to go there, you will only count 50 with your onboard clock.
And if you edge close to c, the distance will become infinitely small. In the end the whole 3D universe will be compressed to a 2D plane for you. Imagine that!
To joke around a bit, if you could go over c then maybe you could burst out of this universe and enter a different kind of universe, where perhaps the lowest speed is c instead of the top speed there. OK OK this doesn't make as much sense, but, feel free to give your ideas on this.
I posted a comment before realizing this was a fairly old video. Maybe you'd have an answer? If the time aboard the ship is actually dilating, then my perception of objects outside the ship should appear to quicken in proportion to time aboard the ship slowing shouldn't it? If so, then the apparent relative acceleration of the object passing the window should still appear constant, right? I shouldn't perceive that length contraction. Unless time dilation doesn't affect perception, at which point I would feel like I was stuck in slow motion. Then again, since perception is dependent on electrical signals traveling through nerves and brain matter, and C is constant from all reference frames, depending on which way I was facing at near light speed, these signals would travel very slowly along some (forward facing relative to the ship's direction of travel) nerves and very quickly across other (reward facing) nerves, so who knows if my brain would even function correctly at that point.
@@CallidusVeloxI was thinking the same. If we were traveling toward an object at the speed of light, we might not be able to interpret what we were seeing but if we calculated our deceleration we could still travel to an object at the speed of light or faster and not crash into it. We could slow down to a speed we could interpret and still have reached the object at what we would expect having traveled at the speed of light
@@CallidusVelox ffs UA-cam deleted my reply....
Basically I said you don't feel in slow motion. The passage of time you experience never changes for you. You may see the universe accelerate though.
For example, if you travel at near light speed towards a rotating star system, you would see it rotate faster.
@@Albtraum_TDDC That's what I'm inclined to believe, mostly because I've read too much science fiction, but how do we know? I guess we won't until and unless we subject a human to near light speeds, but how would the delay of energy traveling through (I believe he called them) motion carriers affect the brain? Like, if we had a skateboard with a lightbulb at the front and one at the back, both the same distance from a power source sitting in the exact center of the skateboard and we sped the board up to some appreciable fraction of C and then flipped the switch, then the light at the rear of the board should turn on before the light at the front, right? How would that same effect work on the electrical signals traveling through our brain? How would that in turn affect our perception? Would that result in our perception slowing to match the slowed motion of our surroundings, or would it just make a confused mess of the inner operations of the brain?
@@CallidusVelox motion carriers will not affect your brain because you're all in the same inertial frame of reference.
You might appear weird for an observer on a different inertial frame of reference though.
The only difference you'll see is on things in different inertial frames of reference. Like a pendulum inside your spaceship will keep working the same way to you.
But if you're going over 99% of c towards a rotating planet, you'll see it rotating a lot faster than when you were stationary compared to it (same frame of reference).
Sir, Can you make a video on misconceptions about electricity I tried to understand the transfer of energy in wires from other channels but it was hard and some of those concepts are still quite weak.
I do have a playlist tagged in my homepage.
@@Mahesh_ShenoySir, I watched all those videos and it helped me a lot, but I had watched Derek Muller's (a PhD physicist) video where he claims that electrons carrying potential energy around a complete conducting loop transferring their energy to the load is all FALSE.He explains that how actually energy is transferred through electromagnetic fields and electricity flowing in one isolated conducting wire can cause electric current in the nearby isolated conducting wire.
1st video where he discusses the main question: ua-cam.com/video/bHIhgxav9LY/v-deo.htmlsi=yqd0b_RLQ66aEKq2
2nd video where he performs the real experiment: ua-cam.com/video/oI_X2cMHNe0/v-deo.htmlsi=R44c_cECV0L3-t1O
I had a hard time understanding these videos.
Sir, what are your views on his claim and the videos.
@@snaatanraina 1st by Physics asylum and next Veretasium only these two ever did video about ur above statement (poynting vector energy flow) do watch the debate video between derek and electroboom
@@snaatanraina That is correct, Varitasium has a really good video explaining this same phenomena video title is "How Electricity Actually Works"
This is the first I’ve seen of your channel but if your other content is at all similar in content and quality then this has to be the best algorithm based recommendation I have ever received on UA-cam. Thank you!
Great job explaining a very difficult aspect of General Relativity that is hard to grasp without doing the math.
You have a great gift at explaining things intuitively, your students are very lucky to have you as their teacher.
And if he's wrong? Then it's misinformation. And I think he is indeed wrong.
@@nightmareTomek
1. Nobody cares what you think.
2. Just because you're incapable of understanding something doesn't make it false.
@@sendintheclowns7305 Seems like you have no arguments and just dumb belief. I can VERY WELL explain why I think he's wrong, but as you mentioned, I think you don't care about actual knowledge.
@@nightmareTomek On the contrary, I'm always interested in new knowledge.
Where can I find the papers you've authored on the subject?
@@sendintheclowns7305 In the library, but only if you read 123 billion books while standing on one foot, only then you gonna find the holy papers.
Thanks, it was great explanation, yet, it missed some important explanations like:
- Why the speed of light is constant?
- When the clock pointer moves in the direction of the movement it gets understandably slower, but why it does not go faster in the other direction?
- Why can't we consider all the movements relative to the center of the universe and get rid of the whole relativity jargon? Or, can we?
- What is the relation between relativity and Higgs Bosons?
- Are you really saying space is changing, or only our perception of it? And that could mean for the center of the universe?
- What is the relation between all of this and the energy preservation concept in a closed system? And what will happen if we discovered someday that our universe is not a closed system?
These are great questions I hope they're answered
What is the center of the universe? There is no such thing or at least we don't know about it. People usually confused about the center because of the Big Bang theory - they imagine there should be a center of the Bang. But the truth is the universe expand like a balloon, from every point simultaneously. From our perspective we are the center of the universe.
- Nobody knows why natural constants are the way they are. We just know that they... well, are that way, as we can measure them. By "Speed of light" C, by the way, it's always speed of light in a vacuum. Light in a medium like air, water or glass may very much be measured with a speed different from C.
- It sounds intuitive that it could go faster in the other direction, but; It is about the speed at which information, at best, can spread. And that's C. It does not matter in which direction the clock pointer moves, it will slow down from an outside observer's perspective as it is accelerated.
- Where is the center of the Universe, and why should we accept it as a universal reference point? What makes this place better as a center than any other center, what gives it the privileged position? We have to assume that all Rules are the same everywhere, so the center of the Universe is not special, and depending on where in the universe you are, you would observe very different times depending on where you are. Imagine 2 stars going Supernova. Both are 2 Light-years away from you, so from your perspective they go off at the same time. Another observer that is 1 Light year away from Star A and 3 Light years away from Star B will disagree with you, as he observes something entirely different. And a 3rd observer sees it exactly the other way around. Who gets to claim what is real, and why should that reality be privileged above the others? That's the problem relativity gets rid of. The Formulas may seem scary, but the Theory of relativity made the Math in certain field of physics so much easier than everything they had before, and they were measurably accurate.
- I pass that to someone who knows their way around quantum-stuff.
- Spacetime is changing. It is a measurable fact. See Cassini; They flew Cassini around the solar system and send out signals to earth, the duration till arrival predictable... until they send a signal close by the sun. The Gravitational field of the sun made the duration longer, implying that gravitation bends spacetime. And it lined up perfectly with predictions of relativity.
- I leave that to philosophers
I can answer 2 and 5. 2: because although the clock is pointing in the other direction the velocity of the ship is still going one way therefore although on the ship the hand of the clock appears to move to one direction it is actually going in the other (it isn't rotating the other way just moving, also the clock doesn't matter it is about all things such as you or me. when we move the same thing happens and so all of our processes slow down therefore we experience time differently). 5: no space isn't changing just our perception, also wdym the center of the universe
My 2 cents:
- Why the speed of light is constant?
This is an interesting question, but entirely different topic. I saw a video from this channel on it.
- What is the relation between relativity and Higgs Bosons?
I think because he said in another video that the fundamental forces between quarks have also a speed limit, if the atom is already moving the nuclear forces need longer to reach the quarks that are moving away. This should, I think, also apply to the Higgs Boson, that already is responsible for the mass, if it needs longer to travel, that could mean an increase in mass.
But... we don't have a theory of everything yet. Zillions of scientists are working on it, but haven't worked it out.
- Are you really saying space is changing, or only our perception of it? And that could mean for the center of the universe?
I think he's saying space is actually changing, and I think he's WRONG. It must just be the perception.
Imagine a planet the size of a light second. If you stand still, you see the front one second before seeing the back, which gives it depth. But if you're moving towards the planet at close to lightspeed, the time difference between the signals goes down to just a half second, and if you're moving away, the time difference increases to 2 seconds. So if you move closer, it should look contracted, if you move away, it should look elongated. The video guy says it's just contracted, but I have a hard time believing it.
Wow, I'm speechless. This is the second video of yours I've seen, and you just appeared out of nowhere on my UA-cam. I'm truly moved. Throughout my entire life, I've always been very critical of teachers' didactics, especially when it comes to their views on teaching and, above all, the search for the why of things, the real reason behind mathematics, physics, and everything else.
And for the first time, I'm seeing a teacher explain things in such a fluid, passionate, and direct way, questions I've always had, questions that have been eating at me because they seemed like unanswered questions. No one wanted to discuss them or they didn't understand the question I was asking. Your teaching is truly exceptional, and I’m genuinely moved.
I deeply admire you, even though I’ve only watched two of your videos. The passion for searching for the why of things is amazing. Congratulations, really!
I personally hated physics all my life , just becoz of tons of formulas and ridiculously long calculations , I'm 18 now and preparing for Neet ( a premedical entrance test in India ) and I do like the concepts of physics like we got Motion 1D and 2d , Newton's Laws of motions , waves etc . AND I MUST SAY I WATCHED 5 OF YOUR VIDEOS JUST BECAUSE HOW WONDERFUL THEY ARE , it's a piece of art really , and watching this motivated me to go study some physics for my upcoming test 😂 😅b, TYSM bhaiya ❤❤❤❤ , LOVE FROM INDIA
I've never seen this explained so plainly before.
I still can't wrap my head around what happens when there are multiple ship's and a platform's perspectives to all take into account. Here is the scenario:
Ship A is traveling at .75c.
Ship B is traveling at .75c in exactly the inverse direction.
Observer C is measuring the speed of both ships from a third location.
How fast are the ships moving from one another's perspective, and how fast are they moving away from one another from any third perspective such as that of Observer C? If the ships sent a signal to one another using a means of communication that travels at the speed of light, when would it get from one ship to the other? If the ships had an entanglement based means of communication as well, and communicated to one another via both methods, and measured the difference in how quickly the messages arrived, what would the difference be?
Because it still seems to me that there could be some kind of, lets call it "3 Roentgen", situation going on around the measurable vs calculable vs practical c given that all the math insists that ship A and B are traveling apart at...infinitely close to but not quite c. Yet if those ships stop after a year, and set up colonies, and someone builds a super telescope to view signs of the sister colony with, then surely they better know not to expect to see anything of the other colony just one year later from the founding of their colony. The sister colony is located 1.5 ly away, and was only founded a year ago. Well, except that we can prove that they could only have moved 1ly away from one another in 1 year. Shit.
It appears to me to be knots all the way around once you consider the speed from those three different points of reference, and I've yet to hear it untangled in a way I could follow. It seems like Einstein's train didn't take into account the perspective of the lightning bolts, nor the possibility that they might try to compare notes with one another throughout the process, nor what happens after said note-comparing objects in such situations stop and cease to be subject to the kind of length contraction that occurs at meaningful fractions of c.
Thank you so much, you're an excellent teacher and this channel is the only one which finally breaks some mental blockers, and allows me to wrap my head around relativity
Amazing to hear that.!!
This is the first time I’ve actually understood WHY time passes slower for a moving object or person. I’ve seen the photon clock explanation before but never combined with the propagation of information through a body at the speed of light. Fantastic!
I have one question about the speed of light, but first, I would like to ask something about changing frames of reference.
Imagine I stand up and start rotating around my own axis; could I change the frame of reference to assume that I'm standing still, and the universe is the one spinning around me? I know that rotation is a motion which involves acceleration, so this non-inertial motion could prevent this. If that's the case, then my question is answered right there.
But if we can apply the change of frame of reference even in this situation, let's do it. In this case, I am not the one rotating, but everything else but me. This would mean that, from my frame of reference, a chair located 1m away from me would be describing a circular motion, drawing a 1m-radius circle around me, right? Now, let's consider something waaaaaay further from me, like a galaxy on the edge of the visible universe, millions of light-years away:
This same galaxy would be doing a circular motion around me, drawing a circle with a radius of millions of light-years. Consider that it takes 1 second from me to turn around; from my frame of reference, that would mean said galaxy described a circular motion around me in the same 1 second, but if we try to calculate the circular path it took to do so in this single second, considering it's a circle with million light-years of radius, it surely would mean the galaxy moved faster than the speed of light, at least from my point of view.
As I said earlier, a possible answer for this scenario is to understand that my circular motion isn't inertial, so such a change in the frame of reference is not allowed by special relativity. Is this the case?
In General Relativity you can define such a frame of reference. And it's fine to have some things move faster than c there, c is only a local limit in GR.
In Special Relativity, since it's not an inertial frame of reference, it can't be described by a single frame going through time, instead you'll have to switch frame of reference at every moment, which makes that other object's "motion" not a real motion.
@@thedeemon Considering a motion is a change of the energy, your spinning motion is still a real motion in Special Relativity... However the only problem with a Special Relativity is that general energy balance of the open system is barely considered... So that is the reason why amount of energy required to reach C is stated as infinite, while in reality it is just being measured in a wrong manner.
@@lolandypanda motion is not "change of the energy".
Best explanation I've seen yet.... Understood it easily and covered all my confusions
Just came here to let Mahesh sir know , there's none who could have explained electronics better. I hated every diagram and explanation. It was a huge burden for me . Got through the chapter from your electronics lesson @khan academy. I just loved learning it and that was way more interesting. Pretty much all of your vedio lessons are well presented and easy to understand!!! 🙌🙌🙌🙌 thanks a lot sir !
Wow, thanks :) :)
That's very high quality content. Would love to see such a high quality explanation of the twin paradox: why only one of the twins gets old? Pls I didn't understand that even by watching a lot of other videos. By the way, I've clicked the subscribe button at first glance of this wonderful channel!
Thanks a ton. And welcome.
Oh yes, that’s up next. My most challenging project so far!!
Thank you so much!@@Mahesh_Shenoy
@@Mahesh_Shenoy The conversations you have with famous scientists are incredible! Love it!
And it's not just a logically correct theory to explain it without contradiction; we have proof of time dilation. One of the twins will be old if the scenario were created in real life. It's like magic, but not just an illusion; it's a true fact of reality...
It's actually amazing how this guy is able to ask Einstein all these questions and get his answers even though Einstein has been dead for so many years already! Is he able to travel back through time? 😊
With all due respect to Mahesh, who is an excellent tutor, Einstein had already asked and answered all these questions himself which Mahesh asks. Mahesh is simply explaining to us the questions and answers that Einstein explored in an era without the internet.
Makes you wonder: how does light reach the speed of light?
Why is the speed of light taken as a reference point?
Because light has no mass, and therefore goes at the fastest speed, the speed of light.
Because photons have no mass so they all go at the max speed. If they had any mass, no matter how small, it would reduce their speed
I saw Mahesh´s Video and then i woke up in the middle of the night with the exact same question.
Well, technically everything travels at the speed of light all the time. Mass at rest just happens to travel at the speed of light through time instead of space.
This is quickly becoming my favorite physics channel. Great work, Mahesh! It's 1am,I have to work tomorrow, and I just played a gig (3 hours of high energy rock), but what's this? An explanation of length contraction? Meh. I'll sleep when I'm dead. Bring it on!
Oh man, that comment made my day, Kevin! Seriously! Thank you. And welcome to the community :)
Thank you so much for your videos. This is what i was looking for for years, truly. Intuitive understanding of science is really fundamental. If it possible, could you make some intuitive explanation of twin paradox?
That's coming next!
What a brilliant video Mahesh!! Reignited the physics guys
within me ( I am a medical doctor btw).
Will save these videos for my duaghter once she is capable enough to understand these concepts. U earned a sub brother. Keep up the great work!!
I was studying the science of special relativity by einstein, and ur ideas and explanation is helping me a lot, thanks a lot mate :)
Great to hear that :)
0:24 in last video this animation was not clear but u corrected in this one yay🎉
Your videos are amazing, but I think you sometimes oversimplify them, you are not completely wrong but you have forgotten some parts, which does not discredit you, since your videos are quite useful when you are beginning to understand relativity, however here is my position, you have forgotten the addition of velocities, I hope you read this:
Reasons why c cannot be reached.
Observer inside the ship:
The main reason is the relativistic addition of velocities, which means that as the ship approaches "c", the increases in its speed become smaller and smaller, regardless of the applied acceleration.
In addition, the crew member experiences an effect related to changes in the reference frame as the ship accelerates. Although its speed continues to increase, the perception of the distances traveled is distorted. This is not the classic length contraction, which refers to the shortening of objects in the direction of movement, but a progressive reduction in the perception of distances to objects at rest as the ship changes its reference frame.
When changing its reference frame due to acceleration, the distances to objects at rest appear to progressively shorten. This does not mean that the objects appear closer visually, but that the measured distance is smaller than it would be if this effect did not exist. The result of the combination of acceleration and distance perception is a smaller and smaller speed gain, as this reduction factor intensifies as the ship accelerates, counteracting the effect of acceleration.
However, the above effect is based on the fact that speeds add up classically, but in turn if we take relativistic effects close to c, it doesn't make sense. The above effect doesn't take into account the compression of speeds, so it would be accelerating more and more to compensate for the compression and in fact it doesn't put a limit.
An important point is how speeds are perceived from different reference frames. The perception of someone traveling at 0.1c relative to an object at rest (0c) is indistinguishable from the perception of someone going at 0.1c relative to a frame going at 99.9c. In other words, there is no significant difference in how they appear to each other, despite the large difference in absolute speeds. This implies that distances measured by previous frames do not shorten in an extreme way as one approaches "c", but decrease steadily.
An important point is how velocities are perceived from different reference frames. The perception of someone traveling at 0.1c relative to an object at rest (0c) is indistinguishable from the perception of someone going at 0.1c relative to a frame going at 99.9c. In other words, there is no significant difference in how they appear to each other, despite the large difference in absolute velocities, therefore, the distances that previous frames measure do not appear to shorten more and more - in fact it should be an invariant contraction, but because it is the distance measured towards an object at rest and not in motion with the instantaneous-previous frame, that contraction decreases each time it approaches c.
Now, the previous case is also incomplete because, although the reduction in distances no longer increases, we are forgetting that when changing reference frames, not only does our view of the distances measured by other frames shorten, but also time. So not only do we see that it is closer (it did not travel as much), but also that it took less time. The result is that basically both things cancel out and we see that the only effect present that affects the speed of these external objects is the relativistic sum of velocities.
External observer:
From the point of view of an external observer, even if the ship increases its speed, it will never be able to reach the speed of light due to the relativistic sum of velocities, which prevents it from reaching c. However, this is not the only thing that limits its progress.
As the ship gets closer to c, time for it dilates significantly, which causes the acceleration to become even less effective, that is, to decrease with greater magnitude. The closer you get to c, the harder it is to speed up, not only because of relativistic velocity addition, but because time dilation slows down your acceleration even more. This ensures that, from the observer's perspective, the ship will never reach the speed of light.
Summary:
In both cases, there are one or two impediments that prevent you from reaching the speed of light:
• Inside the ship: relativistic velocity addition makes your speed appear to plateau and you can never reach "c."
• Outside the ship: time dilation and relativistic velocity addition cause any further acceleration to be diminished as the ship approaches "c."
As I said before, thank you for the quality of the videos you provide us. I forgive you for the mistake, because you always help me understand things.
I would love an explanation on why FTL travel breaks causality! Every explanation I’ve seen hasn’t made sense to me
Maybe flat earthers are just moving closer to the speed of light than the rest of us?
But Mahesh, can Einstein tell me why my head now hurts after watching this video?
Honestly I love the videos on this subject, they have been a great learning experience.
I feel bad that I found your videos late. But now that I have i want to thank you from the bottom of my heart!
As I'm sitting here watching this, I'm realizing how much thought went into the visuals of Star Trek like when a ship goes in or comes out of warp...at least the later Treks. I guessing the original might not have been able to do those effects even if they were aware or wanted to. Specifically referring to length contraction here.
Thanks, you just answered a question I have been asking myself for years. I always saw the speed of light as a number, and why can we travel faster than sound but not light. Your graphic explanation of time dealation was like a switch turning on.
I have a question, its probably something i didnt get on the video, but imagine being the crew of the ship, it starts at 0km/s and its accelarating (1000km/s)/s, and its traveling through that cosmic plataform. Couldnt the crew use the internal clock of the ship to calculate how much time it takes to reach the speed of light and then when they hit it, print the timestamp and then print again one second later? When they desaccelerate to see where they printed the stamps woudnt it be at one light second apart? (slightly more if you count that they are still accelerating during the stamping) That being the proof that they traveled at the speed or even past the speed of light?
The internal clock of the ship still works normally for the shipcrew, and their perceptions on whats going outside wouldnt matter.
You are one hell of a teacher. I wish I had you as a teacher in school, 45 years ago. I learn things now that I have wondered for a loooooooooong time :)
Thanks , your visualization gives a easier way to understand the concept , But I think one thing we still misses , what about color ? , Doppler effect ?
A new subscriber here. Thanks for a brilliant, easily digestible way of explaining time dilation, etc…
Thank you for this follow up video. For years I've battled with this concept and never knew about length contraction.
This is great stuff. I have felt that after reading enough books, I had about a 99% grasp on the concepts of relativity, but every time I read a new book or see a new video that explains it a slightly different way, I gain a little better "intuitive" understanding of it, like adding a decimal point so I now have a 99.9% grasp of relativity - but just like the speed of light - I never have a 100% grasp of relativity. 😂
Here's my request - because I like your style so much and I wonder how you might add to the intuition of something I have struggled to understand: Can you make a video discussing the chapter "The Frozen River" from Brian Greene's book "The Fabric of the Cosmos". I have read "The Elegant Universe" and "The Fabric of the Cosmos" about...I don't know...20 times...trying to grasp many of the thing he writes, but in "The Frozen River", the idea of all of spacetime existing simultaneously and that being so logically demonstrable by examining the reference frame of a very distant alien moving towards us or away from us...well, this concept has haunted me...because unlike quantum physics, which is so intangible, relativity feels intuitive to me, and so the ideas expressed in "The Frozen River" seem to very logically 'prove' that there is no past, present, or future, but only 'all of spacetime'. But anytime I say that out loud to myself, my mind implodes and I realize that I understand nothing at all.
And, as the contraction continues, more and more of the visual universe will compress as well; the closer you get to the speed of light relative to what you're seeing, the more of the universe will suddenly be visible - at least as what you're seeing is relative to you in the spaceship. Something moving away from you while you move sideways will appear differently than something moving towards you while you move sideways, for example. It's mindblowing how much craziness would happen in a scene with many ships moving near the speed of light in different directions relative to each other.
And then it becomes clear how insane reality gets when you peer at the edge of a black hole......
This is the second time (I have found) a random (highly intelligent) person has explained a complicated issue in a way that is easily grasped. The other was on the subject of 'modes' in music theory.
Some people just have this gift.
This is for my reference
7:31 to 15:00
Thanks for lecture mr mahesh it was good
I was trying to learn this logic from different sources and now i am at right place. Thanks for this explanation, Mahesh👍 👏 👌
Super awesome to hear this!!
Most amazing vdo... Awesomely explained.... Subscribed ... U deserve millions of followers.... Let there be light
The best Explanation ever i've ever watched.
One of The best Physics channel for me.
This was such a great video. It squarely addressed my biggest misunderstandings and misconceptions about special relativity. This video should get pinned to the top of all special relativity and faster than light videos on UA-cam. Great work.
EDIT: I look forward to your upcoming video on the twin paradox which still conflates me.
Wow thank you! Unfortunately, this video is not doing well so far :-/
Anyhoo, working on the twin's paradox as we speak!
Simply a breathtaking content. I have not watched anything with such an excitement for many years, especially at 3 a.m. Thank you and bravo! 👏👏👏
Few Questions I got
1. If we see the ship is contracting, getting squished, won't the distance between the atoms reduce too? that means the c wont have to travel longer distances as we saw in first video?
2. When ship is moving, we saw each other being contracted, but who's actually being contracting and who's contraction is apparent, earth, platform, us or the ship?
3. From our reference frame, we saw that light had to travel more distance between each atom as a consequence of constat c, so shouldn't we see the ship being stretched instead of being squished?
Please let me know what am I missing 🥺
Because if I'm within the ship, I see that distance between the plates of clock remains same, the distance between atoms of my ship remains same, so light should travel at normal time and not the dilated time.
The only thing here explaining why we cannot reach c within the ship is that the entire space around us is squished, it's like there no space left for us to travel any faster. And If we do indeed reach c, all the dimensions of space has became zero from the length contraction equation, as if we aren't even in a space at all
Exactly, from the spaceship point of view, the rest of the universe is contracting, squished, thats why a spaceship that goes beyond 99.9% the speed of light can reach the edge of the universe in a few years of spaceship time, but the rest of the universe and earth will have aged billions of years.
You're confused because, contrary to this video premise, you can't really get intuitive understanding of reality explained through mathematical (geometric) model as if it was its direct representation (ignoring simplifications and hiding some important assumptions).
Let's start with
Space-time - It's a specific type of medium (field), which unlike it was initially assumed (aether) seemes to be moving flawlessly thrugh us when we're in motion. We "detected" it by observing time dilation, which was earlier deduced (by Lorentz) together with length contraction as a reasonable explanation of Michelson-Morley experiment results.
Speed of light (causality) is constant... but only in space-time.
However, arbitrary chosen frame of reference (like Earth or some spacaship) will always MEASURE the same speed, because of 3 things:
1) Time dilation
2) Length contraction
3) The fact that we cannot measure it any other way than bouncing photons back and forth (2-way speed of light).
Relative to us speed of light is not constant - it's just an assumed simplification. Look again at the path in that light clock and try to synchronize it with perpendicular one (in direction of motion) - you should see what's going on.
Now answers to your questions are just a consequence of what was stated above:
1. The only distance that matters is how much space-time your frame has traveled.
2. Each frame moving thorugh space-time is contracted, but without making assumptions you cannot determine how each frame is moving. Realtivity allows you to build coordinate system as if your perspective was absolute - that's why it's so useful.
Even when you can feel acceleration, you can't be sure that perpendicular axis would eliminate space contraction. You probably started while moving with constant velocity in some random direction and that wouldn't change (in flat space).
3. Moving object would (have to) be squished physically, and aproached one geometrically - light from (image of) its distant part will reach us sooner.
@@CodeShudder Thank you for the clear and insightful explanation! Your breakdown of these complex concepts in relativity really helped enhance my understanding. I'll take some time to reflect on these points and explore them further to deepen my grasp of the subject.
@@piyush1365 I should warn you that this is not an orthodox way of explaining relativity. As I said, physicists focus on explaining equations, and the physical reality is scattered like missing puzzle pieces behind abstractions. The first of those pieces for me was @veritasium video on "Why no one has measured speed of light", but the only channel I know of with this approach to the subject as a whole is @dialectphilosophy
Delightful narration, perfect illustrations. Thank you Mahesh.
Damn I realise now I was thinking about it all wrong when commenting. this seems so simple in hindsight. Thank you for the fantastic explanation!
But, that's the beauty. The more we ask questions, the deeper we go. So thanks for asking!
Beautiful. NEVER STOP MAKING THESE VIDEOS!!
Hi Mahesh, This question will really challenge you. You are saying that in a spaceship approaching the speed of light from the Earth's perspective, the acceleration will gradually slow down due to the slowing down of the progress of electromagnetic waves due to time dilation and the spaceship will never reach the speed of light. However, on the other hand, when viewed from the Earth's perspective, the spaceship's length will decrease in the direction it accelerates. Therefore, the distance that electromagnetic waves must travel between atoms will be reduced to almost zero. So compared to Earth, time will almost stop, but the size of the spaceship will also decrease to almost zero. In this case, why is an interpretation made only by taking time dilation into account and it is predicted that the progress of electromagnetic waves between atoms will gradually slow down? As a result, both time and distance are multiplied by the Lorentz Factor and time becomes shorter.
Was really fascinated watching your recent videos.. Looking at your views while backtracking, gotta say you have come a long way sir... And your videos are really good too.. Love the way you explain stuff with great passion.. Keep it up
I Always knew Einstein was a peerless genius. But this explaining what he figured out makes him seem almost supernaturally smart.
you explained very clearly but it is still really sad to see that we will never reach the speed of light
why would you want to travel @ the speed of causality ? )) it's meaningless ))
that's how our universe works.
deal with it )))
Thought of two things just now. The lenght of object, approaching C is constrained from our perspective (up to a material point I believe). It's mass is increasing (up to infinity, if I understand correctly). Making this object effectively a black hole, from our perspective. And making it cause a real impact to us, because of gravity, forcing us to fall onto it. And as we begin falling, I mean as we start to accelerate towards it, it makes relative acceleration between us and the object less than before we start moving. It thrilling relation.
I think this is the best explanation I have heard about this. I don't know much about relativity, but can someone explain why the speed of light is said to be constant? For example, if you were on a ship going in one direction at 70% of the speed of light and saw another ship going in the opposite direction at the same speed, wouldn't that ship appear to be going at 140% the speed of light?
Food for the brain! I will spend many nights drifting off to sleep, contemplating what your video says with all its ramifications. Thank you so much!
Mahesh, you honestly did a very good job, one of the best explanations of relativity I have heard. But there is a big problem. For this to be correct there would have to be a constant point of reference in the universe, e.g. a reference frame that is not moving relative to the others. But everything is moving, no one can say which frame of reference is still compared to the other. Consequently time dilation would cancel out when the point of reference became the same or said another way, is a function of the observer. If you change the observer’s frame of reference you change his perception of which time is dilated.
Hi Mahesh, I recent discovered your channel and I find your vidoes very intuitive as you say it. Could you please now add the concept of gravity in relativity to explain the concept intuitively? ❤
Theres a fundamental understanding some people are still not getting and is not quite addressed in this video despite it being very accurate. This is all about the "speed" of light, but velocity in propoportion to space and time is locked in people's mind with a newtonion physics mindset. The video addresses the time experience for both observers, and it addresses the length contraction effect for the ship travelers as to why that time dialation doesn't ruin their perspective entirely. It does not directly address the perpective of the ship traveling TOWARDS an object and how they see space/time in reference to the approaching object.
It's true that from earth, as that ship accelerates at constant rate, it would appear from the earth that it slows down as it gradually approaches the speed of light.
It's true that from the ships perspective, length contraction would distort what earth looks like assuming they could somehow watch it accelerate away from them.
Its true that at no point will that ship travel faster than the speed of light from the ship or the earth's perspective.
However, people get hung up on that concept that you can't travel faster than light and they want to invent hypothetical travel methods of FTL or worm holes / etc. People still assume that if you are on a ship that only manages to go 99% the speed of light but you want to travel to a distant planet 1000 light years away, you will need to enter hypersleep since it will take 1010 years to get there. But its important to understand what the ship experiences. Say a friend left earth at about 299.5km/s (light speed is about 299.79km/s) then it would indeed take 1001 years to get to the planet and earth would be very different. But your friend does not need to travel faster than light to get there in his lifetime. He would have only experienced about 45 years before arriving on the planet. Due to length contraction, upon leaving earth at that velocity, space would not be the same to him as it is to somoene on earth. The planet would immediately look like its only 0.045 light years awat, not 1000.
To change constant velocity to acceleration to be a little more realistic, lets say they left earth's atmosphere at 15m/s^2 and could sustain that level of acceleration indefinitely. The coordinate rate the traveler experiences would end up becomming "faster" than light without violating physics, due to length contraction changing the apparent distance of the object to the traveler at the same time the traveler is increasing their speed towards the object. The visual experience is still limited by light as it could never "look" like the light of that object is coming at you faster than light. However, the traveler will fly past the planet at absolutely insane speeds after little more than 5 years of accelerating at that survivable rate.
Long story short, you do not need to go faster than light to essentially travel many light years in a fraction of years. If you could travel at 99.99 repeating% of light speed, and live, it would appear from your perspective that any distance traveled was practically instant.
You are as talented as mr tyson . You have a special skill to teach people about physics
This is one of the best physics channels I have ever seen.
I’d love it if you a did a video that explains why gravity causes time dilation. What is the physical reason/process that causes this to happen?
Yes! I do have a list of general relativity videos lined up!
In short, because it causes the paths of force transfer(light) to be longer, and for light to conserve its speed time needs to be slowed down.
That's by far the best engaging and intuitive explanation.
You are a great Educator.🏆🏆🏆
Thank you.
Hi. Will you make videos about general relativity too? I really hope so. General relativity is something I never understood, but I am very confident you could make us understand. Congratulations for these amazing videos.
Hey, great work Mahesh, but can you also tell us why time dilates because of gravity? Like why it takes so long for an object to fall into a blackhole to an outsider?
Amazing channel, you have such a great way of explaining this complex subject matter. So glad I found your channel. What did you make of the Interstellar movie? Did you like how they addressed time dilation?
Bro went back in time each video to personally ask Einstein these questions, that's some dedicated content creator
Mahesh, most boats have navigation lights red-right, green-left, white-rear… we can’t accelerate past c, but we could accelerate 2 ships to 3/4 c in opposite directions approaching each other… what happens to the lights as they approach/accelerate do they change color!? When the ships pass each other, would there be a flash (like a sonic boom)? Once they pass they become “invisible” to each other… would they compress each other/ could you take a picture at the moment they passed, or would the compression make them invisible to each other before they passed… if one ship slowed down after passing, the both ships would reappear?! Would the reappearing ships have “normal” color lights!!?
The relative speed will always be less than c! So, we get the usual blue and red shifts
I have watched few videos of yours, and i'm fascinated by your effort to make regular minds understand high lvl physics by an intuitive way. I wonder: do you think the secrest of the world can be teach/learn this way? I have a bad feeling that our science reached a point where human intelligence can't keep up with such complicated theories, like there was a 'barrier' of knowledge for us... Maybe AI will break this barrier, I don't know, but you make me belive again. Well done, you are a Real Teacher
What would be the difference in perspective if instead of moving away from something, we move towards it/it moves towards us?
Wow, I just found this channel and am amazed that I can understand physics when you describe it here more than I have ever before. I am curious, maybe a question you have already answered, if you look at the spaceship, that is travelling very close to the speed of light, from inside where an object's magnetic forces are not distorted and accelerated that object, would that object then be traveling closer to the speed of light, or because it started at 0, would the same amount of effort to get to the speed of the spaceship be required to move it.
It is known that when we need to multiply two scalar quantities, we use the algebraic method (e.g. 3m × 5kg = 15 kg-m).
However, when we study about vector quantity we realise that we have two different ways to multiply vectors which give two different answers.
Why is there a need of second way? If there are multiple ways, then why only two, not 3 or 4?
Explain in detail please sir.
So beautifully you explain all. My mind becomes calm and full of tranquil.
I have a few questions that I’d appreciate someone answering :)
If the ship were to decelerate and come to a stop, where would it be in space and how far away from where it started
Now that both the observer and the spaceship are at similar relative speeds, how long has passed for both the person in the ship and the observer
I have another question. What if we go back to time dilation. Two observers are moving at a relative speed to each other. Both will measure the other at motion and themselves at rest. That means both will measure the other to be moving more slowly through time. That means both will measure themselves to be older after a set amount of time. This makes perfect sense in relativity, but what would I measure if I then accelerate to match the other observer's velocity? If we both stay older than each other, a contradiction arises. So what happens when I accelerate to the other observer's velocity and who would be older? I heard on quora that this requires some very advanced math, but if anyone could explain this to me even though I'm probably not on that level yet, I would be so grateful. The rundown of what I understand is this: The symmetry somehow breaks when one of the observers accelerates to the other's speed. I want to know how it breaks. What would either of them measure?
I think what everyone wanted to see was what it would look like from the point of view of someone on the ship who is looking out the front windows (ie, in the direction of travel). Every scifi show set in space has their own version of the starfield effect - how close were they ? What would it really look like to accelerate towards a high percentage of c, while facing the centre of the milky way ?
17:50 Flatearthers would be very happy with Einstein's relativity
1. If electron flow is at the speed of light, electrons must be massless or pure energy? Or is electron flow just not at the speed of light?
2. If electron flow is at the speed of light, how can I accelerate the electron flow without infinite energy?
Very good video and explanation on spacetime and how it actually works, well done on the visual representation.
The thing I dont get is, what is a resting state? What is resting in the universe? Wasn't movement supposed to be relative to objetcs? Or is there an objective frame of reference in space?
What an explanation. What a video. Amazing content... this is probably one of the best videos I have seen in a long time. Great work.
Wee meters, the smallest of meters.
This is all in good spirits. I love your videos. You’re an astounding teacher. ❤
I lol'd. : D
I literally didn’t know v and we are pronounced differently. My whole life has been a lie. Time to learn some phonetics I guess 😂
While length contraction is a very real effect, it wouldn't be quite as visible to a relativistic observer as one might think: light from different parts of an object arrives at different times (light from further parts of the object arrives later), and light from the back of an object that would normally be blocked can end up reaching the observer when the object is in motion (while light from the front that would normally reach the observer can be blocked). As a result, a relativistic object appears to have rotated, and for a sphere, this ends up cancelling out the length contraction, so that while the sphere *is* length contracted, you'd still see a circular outline at any speed (but would see a different side than you would at rest). The event is known as Terrell rotation.
I do have some questions left. I do not dare doubt Einstein, but I do like to challenge him. I have no knowledge about the theory, only my real interest.
1) While we cannot see the ship move while near, at or above (which cannot be) the speed of light, we have a reference frame of our starting point and where we want to be. Then even if we did not SEE ourselves moving, we actually did right? So if we pushed ourselves past the speed of light and then slowed down again, shouldn't all the parts (atoms, subatoms, largers or smallers bits) still be there and see ourselves at the destination, faster then light reaches us? (then we could see ourselves coming 😀)
2) When even our Universe is turning at VERY high speeds, isn't our own reference frame wrong to begin with? Our at-rest state. Who's to say we aren't beyond light speed already? Since our universe could be the ship we are inside of.
3) Particles only slow down when colliding with other stuff right? Gravity, other mass or forces etc. So if en engine is accelerating and will keep doing so, it WILL go beyond light speed until it stops pushing. The question will be how much time 'outside' will pass. If the universe wouldn't end, it could take a googolplex (yeah, that's a real word) to reach >100% of the light speed right? I think the real problem is that we cannot calculate large enough numbers or computing power to calculate the time needed 'outside' to 'see' something reach light speed.
There is still no evidence (from what I gather, DO read on!) of a REAL barrier that stops something from going to light speed, only that it will take such a large amount of time we cannot calculate it (yet). Something like the number Pi. Maybe Pi is infinite, maybe it actually has an end. There is one certainty, we will not find out ourselves.
Issue would be external light being blue shifter (looking forward) or read shifted (looking behind). forward looking Visible light would be shifted into x-rays, and looking behind, visible light would be red shifted into radio bands.
Wonderful video Mahesh, thank you! In previous videos you gave a very intuitive explanation for time dilation by showing that information transfer takes longer in a photon clock when it's traveling horizontally. Is there a similarly intuitive explanation for length contraction that relies on the physical properties / geometries of the system?
Brilliant explanation as was the last. I still dont quite understand it all but I understand more. Love that youtube presented your channel to me. Here is a comment so Algo the algorithm may help you grow
This is complex stuff. It took me ages to wrap my head around all these (and I am still barely scratching the surface). Thank you :)
this was good! thank you
I like this guys enthusiasm.
Dude you are changing the world! 70k subs on the way to 20mil +
So, if you are travelling to a star 99.9 light years away from Earth and travelling at 99.9% of the speed of light. The dilation factor is 22. So from an earth observer it would take 100 years to reach the star. How much time would pass for the person on the ship? 100 years/22 or approximately 4.55 years? Or does the length change make this also 100 years?
i find physics and maths really fun and interesting, this video really made relativity understable and i like to think more about it
The answer is actually much more simple than that.
A photon is energy.
An electron is an energy carrier.
There's a maximum amount of energy an electron can carry.
An energized atom cannot travel faster with energy than the energy can travel on its own.
Its a simple way to ensure that the speed of atoms are capped.
Lets imagine that we can maximize the energy an atom is allowed to contain, then the mere fact that the energy now has a mass to propel would always make the atom with the mass, slower than the energy without the mass.
It's like finding the maximum speed an explosion of 1 liter of fuel can propel a golf ball. Then trying to make that same speed with a bigger pool ball.
There's also something deeper and more fundamental going on here... specifically to do with photons, energy and light.
Please, make video on Electricity. What is exactly Electricity? And what is exactly voltage?How do they work?
Well, he already has made several videos on that. You should search first and then write the comment.
You will and should get billion views and subscribers. I could never met Einstein but I feel like I could understand Einstein through your explanations.
Great content! Can't wait for your videos on General Relativity!
Explained very well. Great work.