Very original comment. I have not read this same comment a million times. Obviously not. Your brain sure comes up with new creative ideas every time. Bravo
@@jesusthroughmary its hard to imagine "jesusthroughmary" actually appreciates the physical science involved. don't you people think the earth was made 6 thousand years ago or something? I'd always figured with folks like that in your community, y'all must not appreciate science very much?
I fell asleep listening to Veritasium and somehow ended up here when I woke up to this. If Veritasium is an exotic starter, then this is the main course and I'm loving it! Good Job you.... YT machine learning recomendation engine!!
Thank you Stanford University, having access to these lectures means more than you know. I was an average student in grade school who couldn't pinpoint what direction to follow and now at 28 it's clearer and although the signs have always been there I'm seeing and listening with clearer senses and again I'm so very grateful you have these lectures available for people like me. Education in this world is important more now than ever and I hope you all know how much value you're adding to the world by sharing knowledge. Thank you again so very much. I hope one day to be an official student.
Thank you so much to whoever was behind the decision to film these and post them online for free. I'm going through it slowly but it's amazing to have the opportunity to watch these amazing lectures.
Yeah it is or sum i wake up every morning, & when my mind is freshest i make a few flashcards. A gentle stream cuts through stone I use supermemo to stop me from forgetting what i learnt This is because in the past, i worked through this really nice, gentle big book called Engineering Maths (by KA Stroud). But I forgot a lot of it = it was rather a case of "in 1 ear & out the other". But with Supermemo the knowledge is permanent
I cannot think of physics without prof Suskind. It is amazing to see a genius like him teach being humble to the core despite his genius! He is exemplary in every way! God bless him and wish he gets his Nobel Prize which he richly deserves very soon!
Veritasium - Simplest math problem no one can solve, UA-cam autoplayed this next ... um ok .. sure I suppose I'm ready for this now, after watching that... saved myself thousands on college ..
I respect professors who go read the original work of scientists and turn it into an amusing lecture. I just enjoyed every second of this video. Thank you very much Sir
Wondering why these kind of lectures help me sleep so well when I came to the ugly realization that it's most likely because it brings me back to a simpler time of... sleeping in class.
Many thanks to Stanford and Prof. Susskind. I've watched a few series, and I really love the way he explains things, in a very logical and simple way. Helped me understand many things that apparently were not as clear as they should have been to me!
This first lecture really blew my mind the first time i saw. This isn't gold; it's platinum! Susskind continues to inspire my own teaching, and of course, my study of physics :)
Thank you Dr Susskind. Posting this comment right at the top here as a high school physics teacher. The first 4 lectures are the perfect introduction for my students into special relativity, taught the way it was meant to be taught--straight from Einstein's paper, explained in common language. I show these first 4 videos every year at the end of our units on classical mechanics as a follow-up. The kids love them, and love Dr Susskind. Thank you thank you! Follow up--thank you for our list of Susskind-isms--"time is time is time is time", "derove", and who could forget poor Seymore, out there on his world line all alone waiting for a light ray.
It's actually amazing that working through deriving the way space and time relate to each other under coordinate transformations is extraordinarily clear and makes total sense, as long as the only special assumption is that the speed of light must remained fixed. Also, I've always wondered why Einstein would make that assumption in the first place, but his mention of thinking about Maxwell's Equations also makes total sense. You shouldn't be able to make the electromagnetic field vanish by moving fast enough.
TIME DILATION IS FULLY EXPLAINED, AS THE ULTIMATE MATHEMATICAL UNIFICATION OF PHYSICS/PHYSICAL EXPERIENCE IS CLEARLY PROVEN: A PHOTON may be placed at the center of what is THE SUN (as A POINT, of course), AS the reduction of SPACE is offset by (or BALANCED with) the speed of light; AS ELECTROMAGNETISM/ENERGY IS GRAVITY; AS E=MC2 IS F=MA. Gravity IS ELECTROMAGNETISM/energy. (The stars AND PLANETS are POINTS in the night sky.) Time DILATION ULTIMATELY proves ON BALANCE that electromagnetism/ENERGY IS GRAVITY, as C4 is a POINT that is ELECTROMAGNETIC/GRAVITATIONAL (ON BALANCE) as SPACE; AS E=mc2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Time DILATION proves that electromagnetism/ENERGY IS GRAVITY, AS E=mc2 is DIRECTLY and fundamentally derived from F=ma. E=mc2 IS F=ma. A planet AND a star thus constitute what is A POINT in the night sky. It ALL CLEARLY makes perfect sense. Gravity IS ELECTROMAGNETISM/ENERGY. ACCORDINGLY, I have ALSO fully explained the MATHEMATICAL UNIFICATION of Einstein's equations and Maxwell's equations (GIVEN THE ADDITION OF A FOURTH SPATIAL DIMENSION); AS E=mc2 IS F=ma. The Sun AND the Earth are F=ma AND E=mc2. Great. SO, ultimately and truly, TIME is NECESSARILY possible/potential AND actual IN BALANCE; AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. AGAIN, time DILATION ULTIMATELY proves ON BALANCE that E=MC2 is F=ma; AS ELECTROMAGNETISM/energy is gravity. Great. Indeed, this NECESSARILY represents, INVOLVES, AND DESCRIBES what is possible/potential AND actual IN BALANCE. (E=mc2 IS F=ma.) Therefore, INSTANTANEITY is thus FUNDAMENTAL to what is the FULL and proper UNDERSTANDING of physics/physical experience; AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. SO, GRAVITATIONAL force/ENERGY IS proportional to (or BALANCED with/as) inertia/INERTIAL RESISTANCE; AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity. Accordingly, the rotation of WHAT IS THE MOON matches it's revolution. MOREOVER, a given PLANET (including WHAT IS THE EARTH) sweeps out equal areas in equal times consistent WITH/AS E=MC2, F=MA, AND what is perpetual motion; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. "Mass"/ENERGY IS GRAVITY. ELECTROMAGNETISM/ENERGY IS GRAVITY. Gravity AND ELECTROMAGNETISM/energy are linked AND BALANCED opposites, AS E=MC2 IS F=MA; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. GREAT !!! It ALL CLEARLY makes perfect sense. BALANCE and completeness go hand in hand. Very importantly, outer "space" involves full inertia; AND it is fully invisible AND black. E=mc2 IS F=ma. "Mass"/ENERGY involves BALANCED inertia/INERTIAL RESISTANCE consistent with/as what is BALANCED ELECTROMAGNETIC/gravitational force/ENERGY, AS E=mc2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. (Energy has/involves GRAVITY, AND ENERGY has/involves inertia/INERTIAL RESISTANCE.) E=MC2 IS F=ma. Objects fall at the SAME RATE (neglecting air resistance, of course), AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Gravity IS ELECTROMAGNETISM/energy. E=MC2 IS F=ma. It ALL CLEARLY makes perfect sense. Magnificent !!! By Frank DiMeglio
This is what you need to know. THE FULL UNDERSTANDING OF TIME (AND TIME DILATION), AS E=MC2 IS CLEARLY F=MA ON BALANCE; AS ELECTROMAGNETISM/energy is gravity: INSTANTANEITY is fundamental to what is the FULL and proper UNDERSTANDING of physics/physical experience (in and with TIME), AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity; AS the stars AND PLANETS are POINTS in the night sky. TIME dilation ULTIMATELY proves ON BALANCE that ELECTROMAGNETISM/energy is gravity, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity. (Gravity IS ELECTROMAGNETISM/energy.) THE EARTH/ground AND THE SUN are CLEARLY E=MC2 AND F=ma IN BALANCE, AS the stars AND PLANETS are POINTS in the night sky; AS ELECTROMAGNETISM/energy is gravity. TIME is NECESSARILY possible/potential AND actual IN BALANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity !!!! TIME dilation ULTIMATELY proves ON BALANCE that E=MC2 IS F=ma, AS ELECTROMAGNETISM/energy is gravity. It all CLEARLY makes perfect sense. Balance and completeness go hand in hand. E=MC2 IS F=ma. This NECESSARILY represents, INVOLVES, AND DESCRIBES what is possible/potential AND actual IN BALANCE, AS ELECTROMAGNETISM/energy is gravity !!! Comparatively, consider the man who IS in outer "space". Great. AGAIN, the stars AND PLANETS are POINTS in the night sky !! AGAIN, TIME DILATION ULTIMATELY proves in what is a BALANCED FASHION that ELECTROMAGNETISM/energy is gravity; AS E=MC2 IS F=ma; AS gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE. Gravity IS ELECTROMAGNETISM/energy ON BALANCE. E=MC2 IS F=ma ON BALANCE !!! NOW, carefully consider that the stars AND PLANETS are POINTS in the night sky !!! Great !!! "Mass"/ENERGY involves BALANCED inertia/INERTIAL RESISTANCE consistent with/as what is balanced electromagnetic/gravitational force/ENERGY, AS E=MC2 IS F=ma ON BALANCE; AS ELECTROMAGNETISM/energy is gravity. It all CLEARLY makes perfect sense, AS BALANCE AND completeness go hand in hand. E=MC2 IS F=ma ON BALANCE !!! By Frank DiMeglio
UNDERSTANDING TIME AND THE CLEAR MATHEMATICAL PROOF THAT E=MC2 IS F=MA ON BALANCE, AS ELECTROMAGNETISM/energy is gravity: ELECTROMAGNETISM/energy is gravity. The stars AND PLANETS are POINTS in the night sky. Gravity AND ELECTROMAGNETISM/energy are linked AND BALANCED opposites, AS ELECTROMAGNETISM/energy is gravity; AS “mass”/ENERGY IS GRAVITY; AS E=MC2 IS F=ma. Therefore, the planets will move away very, very, very slightly in BALANCED relation to what is THE SUN. (Also, carefully consider what is THE EARTH.) Great !!! This explains the cosmological redshift AND the “black hole(s)”. GRAVITATIONAL force/ENERGY IS proportional to (or BALANCED with/as) inertia/INERTIAL RESISTANCE, AS E=MC2 IS F=ma ON BALANCE; AS ELECTROMAGNETISM/energy is gravity. Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS E=MC2 IS F=ma ON BALANCE; AS ELECTROMAGNETISM/energy is gravity. Gravity IS ELECTROMAGNETISM/energy. “Mass"/ENERGY involves BALANCED inertia/INERTIAL RESISTANCE consistent with/as what is BALANCED electromagnetic/gravitational force/ENERGY, AS E=MC2 IS F=ma ON BALANCE; AS ELECTROMAGNETISM/energy is gravity. SO, the rotation of WHAT IS THE MOON matches it's revolution; AND objects fall at the SAME RATE (neglecting air resistance, of course) !!! Time dilation ULTIMATELY proves ON BALANCE that E=MC2 IS F=ma, AS ELECTROMAGNETISM/energy is gravity !!! It all CLEARLY makes perfect sense, AS BALANCE AND completeness go hand in hand. Balanced inertia/INERTIAL RESISTANCE is fundamental. Time is NECESSARILY possible/potential AND actual IN BALANCE, AS E=MC2 IS F=ma ON BALANCE; AS ELECTROMAGNETISM/energy is gravity !!! GREAT. Stellar clustering ALSO proves ON BALANCE that E=MC2 IS F=ma, AS ELECTROMAGNETISM/energy is gravity. By Frank DiMeglio
@@frankdimeglio8216 Speed of light being constant in al frames I believe Einstein learned from the Michelson-Morley Experiment into the luminiferous ether.
this video is amazing. Truly easy and fundamental. Thank you so much for the upload. Much appreciated. And professor Susskind, I must say that I am a big fan!
Great lecture. What I really miss in all those lectures are examples. Examples with numbers. The course would take twice as much time, but the number of people who understood would increase much more. I know it; I do lectures on much less complicated technical subjects, and as soon as you come from theoretical equations to practical use, it can be seen how many students get enlightened. Covariant and contravariant vector, show the transformations - 2 dimensions would be enough.
This is a God sent seriously. Been reading through three books today and a lecture discussing the same topics u talked about in the first 11 minutes. Yours made so much sense - I really appreciate all the chronological science history as you teach. So many leave the little things out.
I watched this, well more like tried to watch this right before I started my bachelors in Astrophysics a couple years ago. I was beyond lost. Now after a couple years under my belt, it makes so much sense now. I love the way he teaches this topic.
Wow. when he got to the lorenz transformations I was just blown away. I had seen this before but seeing how einstein actually worked this through... it gave me chills. a true legend. thank you prof susskind.
The funny thing is, if you know absolutely nothing about physics, you can discover SR all by yourself. Sadly, most folk have been trained to think that this is not the case at all, even though a high school dropout can do it.
This knowledge is so valuable. It was so difficult to find a lecture that used this simple method of plotting these quantities on a Cartesian plane. That makes it so much easier to see how all these quantities relate. Sure, it is a longer video than you find on some of the pop science channels that are popular. But an investment of a hour is more than worth it. The attempts to gloss over this step on popular videos might make the video get more plays and likes. But it shorts the viewer on the necessary steps.
UA-cam knows me well. Fell asleep watching a Jon Stewart interview, woke up to this… luckily I am passingly familiar with physics and relativistic physics so, I quite enjoyed this and was unable to go back to sleep.
This is great! I am in the equivalent of last year of high school and love watching university lectures of subjects I have in school. Having a proper explanation of these concepts makes understanding the analogies we’re fed in school a lot more digestible. Can’t wait for University next year!
I'm a freshman undergraduate student. There would be no way I was going to pass the first semester exams if not for lectures on physics from mit and Stanford. In my university, they barely explain this stuff and expect you to already know/understand it anyway
These special relativity lectures, and the whole series of physics courses of which they are a part, are excellent. Susskind's explanations are very thorough. Thanks to them, I understand the material better than I did when I was a physics major 40 years ago. He does occasionally slip up with minus signs, but this gives you the opportunity to redo the derivation and figure out where the slip occurred, where doing this definitely helps you learn the material better.
Rather, the idea is based on an error in logic: _"The 2 photons will have been sent simultaneously only if they arrive simultaneously at the midpoint, therefore if they arrive simultaneously at the midpoint then they will have been sent simultaneously."_ That is, "if p then q, therefore if q then p". This is a formal fallacy in propositional logic, called "affirming the consequent". The truth of the matter is that the photon at B is fired later than the photon at the origin, and this because it has to travel a shorter distance in order to arrive at A at the same time as the photon from the origin arrives at A. And so we see from the chart that B is at t>0. So there is only 1 time scale, t, for you can't have a moving system of clocks and have those clocks not tick. Clocks tick. That's what they do. So t' is only 0 along the x axis, which is where (and when) the first photon is fired, for the first photon is fired at the origin and at the origin t' is on the x axis. After that, t' is greater than 0, because its clocks are ticking. And so t' is synonymous with t, and therefore superfluous: we only need t. The problem is that the issue is not really a physics issue, but a logic issue. Physicists are not necessarily good at logic. Logic is a different skill. If you wish to see how SRT is errant at its very first derivational step, just search "Nullification of Relativity Theory via the Sufficiency of the Galilean Velocity Transformation", click on the viXra link, and then click on v2 of the PDF.
Fred = Leonard 28:45 _"My friends who are separated by equal distance: there's me, the 1 in front of me & the 1 in front of him"_ 30:52 _"Let's give these people names: Fred, Anne..._ _& See More"_
Below is an attempt at calculating how many people go on to complete all the lectures. As of July 15, 2021, here are the stats for the views and likes for the 10 videos in this series: Lecture 1: 897024; 6.7k Lecture 2: 212144; 1.2k Lecture 3: 225383; 1.2k Lecture 4: 139619; 779 Lecture 5: 99385; 543 Lecture 6: 80824; 512 Lecture 7: 65712; 478 Lecture 8: 67962; 480 Lecture 9: 74709; 464 Lecture 10: 71365; 508 Around 900k people watched the first video, and 6.7k liked it. 71k watched the last video, and 508 liked it. As a rough first approximation, at most around 8% of the viewers who watched the first video might have gone on to complete all the lectures.
At 1:27:25, it shows t is dilated when t'=1 from the view point of moving frame, but t' is contracted from the view point of the rest frame. For example t=1, x=1 are both contraceted in the moving frame to sqrt(1-v^2). Time and space are both contracted in the moving frame. Contraction of time is slowing down of the clock, i.e. dilation of time.
Approaching philosophical questions happens all the time with Sean Carrol biggest questions in the universe, Cosmology beginning of universe and black holes. Sean Carroll is another great explainer.
@@HughesMath1 🔹°= -🔹🚽❓♓/t-2.Special relativity x y and z.Transfers and rotations.Spacial set of coordinates.Thank you thinking out loud use of objective units.Yipes,my coordinates are different from your coordinates.I end up apologizing to someone.Is it year of the Ox yet?
There are professor's who are born to lecture, and he's one of them. Amazing. The way interacts, asks questions during the problem solving he's awesome
I have seen this type of work from renowed teachers but the way Einstein himself have done and explained by this sir was absolutely great....thanks for making it understandable
At 1:02:25, the equations of lorents transformation has a domain of all real numbers except for v=1. The equations derivation, however, depends on x=t when v = 1. Refer to the video at 50:34. Isn't it a big contradiction? Trying to explain the equations when v = 1 seems to be completely meaningless.
1:04:35 - since t=vx (44:36), t'=(t-vx)/√(v/c)=0, contrasting with the answer later of t'=t ! How to explain it? The math in this lecture is beautiful, e.g slope of line 0‾b = v (44:25) 👍 33:20- this is the foundation of the following contents, wish have spent more time on it.
NO KIDDING! YOU KNOW, I WAS THINKING THE SAME THING! IF I WERE TAKING A CLASS I WOULD HOPE TO GET SOMETHING OUT OF IT.( REGURUTATINE. IS IT WHAT I AM PAYING 4. SOME1 HAS TO TEACH A CLASS BASED ON EVERYONE ELES'S HISTORY BOOK BULLSHIT! HOW MANY TIMES DO I HAVE TO SIT IN A CLASS WONDERING? WHEN ARE YOU GOING TO TEACH ME SOMETHING? YES, YES. I HAVE HERD ALL OF THAT BULLSHIT BEFORe. FUCK! I COULD WATCH THAT ON THE DISCOVERY. HISTORY CHANNEL. LOLOLOLOLOLOL JUST( AMGEN ) ALL OF THE MONEY THAT I COULD SAVE!!! WOW!!! THAT IS FUCKING AMAYZZZZZING. P.S. LOOK AT( AMERICA IS NOT THE GREATESt CONTRARY) WE NEED TO WAKE UP PEOPLE. BECAUSE I DON'T LIKE BEING 2ND BEST!!!!!!!!!!!!!!!!!!!!!!!!
CLASSIC FIELD. YOU DO MEAN OR IS THAT WITH AN I? CLASSIC POS. TELL YOU WHAT HUNNY. IF YOU ARE THAT GOOD. LEAVE ME A MESSAGE. WHEN YOUR N- PHYSICS IS BETTER THAN MINE. PLEASE CALL ME!! I CAN'T FUCKING WEIGHT. M-0 G-0. Know if EYENSTIN. DID I SPELL THAT WRONG. TELL ME THEN. WHAT WAS HIS UP TAKE ON HYGIENE. YESTERDAY'S BULLSHIT.
It's a very interesting lecture. However I can't understand is why at 47:17 did he put x' = (x - v*t)*f(|v|). Actually there is no obligation to put such equation. From a general perspective we can simply put x' = h(x,t,v) and h = 0 when x = v*t. If someone understood why he made such an assumption, I'll be glad to hear the explanation :) Thanks !
36:18 I really don't understand where the "x + t = constant" bit comes from. Everything else in this lecture makes sense, but I don't get where he came up with that property. Could someone help me understand? Thank you.
That's the equation of light going the "other" way (we have only one direction, the x axis, so we can talk about light going forward and backward in a certain reference frame). The equation for a light beam going forward is x = d+t (so the slope is 1, the speed of light; d is a constant representing when the light beam is at position x=0). In the case of the lecture, d is 0, so the equation is x = t. The equation for a light beam going backwards is x = d-t (d has the same meaning as above, but slope in this case is -1) => x+t = d (a constant) Hope you understand now! :)
+Veridian x + t is a constant because.. well I'll give a quick proof actually. so, a line with that angle has a slope of 1, or -1. In other words, f'(x) = +- 1 so, if we take the antiderivative, we have.. f(x) = +- X + A where A is a constant. so, where the slope is positive, f(x) = x + 1, we can express it as x - t = constant or rather, x - f(x) is a constant. how is this? X - (X + A), or.. X + F(X) = -A -A That's not a variable.. that's a constant. Replace F(X) with t because t is on the y axis there, and you have your answer. meanwhile, X + (-X + A) (negative slope) (X - X) + A A Also a constant.
1:06:26 If anyone else is confused about why V on top is divided by C^2 as opposed to C: V and X are both proportional to the value of C. V/C*X/C == V/C^2*X.
Around the 30.30 minute mark, you indicated that a stationary mover would move along the x-axis but in reality, the stationary observer would stay at x=0 but move up the time axis. The time changes for the stationary observer but not the spatial extent. Or am I missing something.
"In May and November, the Earth is moving at "right angles" to the line to Algol. During this time we see minima happening regularly at their 2.867321 day intervals. However, during August, the Earth is rapidly moving towards Algol at about 107,229 km/hr as explained on my How Fast Are We Moving? page. (The Earth moves approximately 202 times its own size in one day.) So in 2.867321 days the Earth moves about 7,379,039 km closer to Algol. _But the varying light from Algol doesn't know this - its light waves left Algol 93 years ago and are travelling at a constant speed._ The result - we "catch a bunch of minima early" during August as shown on Chart 2. Exactly the opposite happens during February - the Earth is moving away from Algol that fast and it takes longer for the group of minima to reach us so we see them taking longer between events. How long? 7,379,039 km divided by the speed of light 299,792.458 km/sec is 24.61382 seconds. So in May and November when we are not moving towards or away from Algol - the period seems constant. It is our rapid movement towards or away from the events in August and February that causes the timing differences." I assume that light is passing the earth at c when the earth isn't moving towards or away from Algol. In February the earth is moving away from Algol and the time between the eclipses is 2.8675875347 days and the light is passing the earth at 186,265 mi/sec. In May and November the earth is not moving towards or away from Algol and the time between eclipses is 2.867321 days and the light is passing the earth at 186,282 mi/sec. In August the earth is moving towards Algol and the time between eclipses is 2.8670608912 days and the light is passing the earth at 186,299 mi/sec.
CONCERN SUMMARY: What is the Symmetry assumption motivation? DETAILS: At the point where we found: x'=(x-vt)f(v) t'=(t-vx)f(v) To find f(v), since "who is to say which frame is moving", we (Einstein) make the assumption that you can't determine, so they should be symmetric, so: x=(x'+vt)f(v) t=(t'+vx)f(v) hence we can now find f(v) But what is the motivation behind that assumption? What is the exact motivation for ruling out the possibility that there is an absolute speed for observer 1 and observer 2 with respect to something?
1) "But what is the motivation behind that assumption?": I suppose that you are referring to suddenly these two equations appeared x=(x'+vt)f(v) t=(t'+vx)f(v). Answer: You don't need more assumptions than these two equations and the fact that any referential see light with the same velocity. For this absolute speed, in both equations ,we must have: x^2 + y^2 + z ^2 = c^2 * t^2 and x'^2 + y'^2 + z'^2 = c^2 * t'^2 (Equations for some light beam starting in t= 0, at the origin, in the two frames.). The movement is in one direction so: let's assume y = y' and z = z' ( these two coordinates won't interfere in the derivation, you can assume different (y,y'), (z, z') and the same result would appear). So, now we have : x^2 - c^2 * t^2 + c^2 * t'^2 - x'^2 => x^2 - x'^2 + c^2 * ( t'^2 - t^2) = 0. Now substitute x' by x'=(x-vt)f(v) and t' by t'=(t-vx)f(v), and remember that this must always be true, so force to be an identity for x and t. You will get the transformations from there. 2) What is the exact motivation for ruling out the possibility that there is an absolute speed for observer 1 and observer 2 concerning something? : My answer: any observer can determine speed in their referential. They only need to measure space and time. If you can't determine velocity in your referential, this whole discussion is pointless. For me, he blundered at this point. You don't need to consider relative velocity between these two frames. You can derive the relative velocity from the transformation. 3) In my perspective, there are many leaps of ideias. For example, These two equation x'=(x-vt)f(v) t'=(t-vx)f(v), come from the fact that x' is invariant in lines x = vt + k ( because, for any observer with velocity v determined by observer 1, in their frame, they don't distance from each other) and t' is invariant in lines t = vx/c^2 + k (this derives from the definition of simultaneous event from Einstein) ( Here I'm not considering c = 1, but you can). You just need to see that lines t = vx+ k (In observer 1 referential) (I returned with c = 1) have the same t' (Each one with a different t', but in the same line t' is the same). So this lines are the level curve for the function t'(x,t) and then we have t'(x,t) = (t -vx) * f(v). The same can be said for x'(x,t) = ( t -vt) * f2(v) relative to lines x = vt + k. See one thing: x = vt + k => k = x-vt. k is a constant for the line that denominates the linear coefficient. So, for some k : x'(x,t) = (t-vt) * f2(v) => x'(x,t) = k * f2(v). For a given v and k, x'(x,t) is a constant.
Clocks and lengths do not actually change in YOUR frame or reference when you are moving. They only appear to in somebody's else frame of reference that is stationary relative to yours. And Visa a Versa..
At 1:15:50, we found using Lorentz transformation that the length of a stationary meter scale measured from a moving reference frame is contracted by a factor of sqrt(1-v^2). But in the space-time plot the length of meter scale from x'=0 to x'=1 along the x' axis appears to be greater than 1 (from basic geometry). What am I missing here?
Here is the problem with Special Relativity. Suppose that there is a clock in a flying airplane. Einstein says this about that clock. "The time which elapses between two strokes of the clock is not one second, but 1/sqrt(1-v^2/c^2) seconds, a somewhat larger time. As a consequence of its motion the clock goes more slowly than when at rest." (Relativity, the Special and General Theory, A. Einstein, p.44) x'=(x-vt)/sqrt(1-v^2/c^2) y'=y z'=z t'=(t-vx/c^2)/sqrt(1-v^2/c^2) inverse equations x = (x' + vt')/sqrt(1-v^2/c^2) y = y' z = z' t = (t' + vx'/c^2)/sqrt(1-v^2/c^2) These equations do not agree with reality because they show that the speed of the airplane is the same as observed from either frame of reference. v is the speed of the airplane and is the same speed as calculated from the time of either clock. We common people live in something called reality where if the pilot of the airplane has a slower clock to time the flight of the airplane, he will get a faster speed for the airplane than an observer on the ground will get using a faster clock on the ground to time the flight of the airplane. What the above equations describe is a miracle, a supernatural event. Here are the correct equations for relativity. x'=x-vt y'=y z'=z t'=t These equations are called the Galilean transformation equations and are the equations that scientists used until 1887 when the Michelson-Morley experiment took place, and scientists found that they could not describe the results of that experiment using the Galilean transformation equations. The problem they encountered was that if t'=t, then the two equations that would show the same speed of light in both frames of reference, x=ct and x'=ct', could not both be true because x and x' were not the same distance unless v=0. But Newton and Galileo were both capable of working simple algebra. If there is a clock in the airplane that shows some other time than t, the time of a clock in the frame of reference at rest. Either of these two earlier scientists could have described a clock with a different rate. They would have just used a different set of Galilean transformation equations with different variables for velocity and time. So if there is a clock in the airplane that is slower than a clock on the ground, then the inverse equations would be x = x' - (-vt/n')n' y = y' z = z' n = n' where n' = is the time of the slower clock in the airplane, and (-vt/n') is the velocity of the airplane according to the time of the slower clock on the airplane. These equations describe relativity, not only for a slower clock such as Einstein describes in his Special Theory of Relativity, but also for a faster clock such as scientists say they encounter in a GPS satellite. So to describe light as traveling at c=186,000 miles per second in both frames of reference according to clocks in those frames of reference, we do not say x=ct and x'=ct', as Einstein said, but x=ct and x'=cn' the times of the two clocks in question. We have now resolved the problem scientists could not solve in 1887 without resorting to length contractions, curved space, or other miracles that have been used by scientists since that time. Scientists, of course, are not going to like this because they are paid trillions of dollars by governments to say that Einstein's description of relativity is correct.
@@hollaadieewaldfeee It is not relativity. I can tell you that much. It sets up time as some kind of force that controls space. Why would the rate of transitions of a cesium atom on an insignificant planet be the controlling force for all other things in existence?
You start by quoting Einstein and then attempt to argue that the time dilation predicted by Special Relativity leads to contradictory or miraculous results when considering the speed of an airplane from different reference frames, but your claim is riddled with misunderstandings. Here are the breakdowns of your argument. Time Dilation and Reference Frames: Einstein’s equations for time dilation, such as t'=(t-vx/c^2)/sqrt(1-v^2/c^2), do not suggest a contradiction or supernatural event. They describe how time passes differently for observers in different inertial frames moving relative to each other. The key point is that each observer measures time and space according to their own reference frame. An observer on the ground and an observer on the airplane will each measure different times and distances, but these differences are consistent when transformed between frames using the Lorentz transformations. Relative Velocity Measurement: Your claim also asserts that the speed of the airplane should be perceived differently by the pilot and an observer on the ground due to differing clock rates. However, Special Relativity already accounts for this by incorporating the concept of time dilation and length contraction. The velocity of the airplane is the same in both frames because it is a relative velocity, not an absolute one. What changes between the frames is not the speed of the airplane itself, but the measurement of time and distance. The idea that a slower clock on the airplane should result in a higher calculated speed in that frame is incorrect because it fails to consider that the distance measured in the airplane’s frame (due to length contraction) would also differ. Special Relativity shows that both time dilation and length contraction ensure the speed of the airplane remains consistent across all inertial frames. Galilean vs. Lorentz Transformations: Your claim also suggests reverting to the Galilean transformation equations as a solution. However, this approach overlooks why Lorentz transformations replaced Galilean transformations in the first place. Galilean transformations assume that time is absolute and the same for all observers, which fails to explain the results of the Michelson-Morley experiment, which showed that the speed of light is constant in all inertial frames. The Lorentz transformations provide the correct relationships between time and space for observers in relative motion. These transformations are not arbitrary or miraculous; they are a necessary consequence of the principles that the speed of light is the same in all inertial frames and that the laws of physics are invariant under changes in reference frames. GPS Satellites and Relativity: Your claim also references GPS satellites, suggesting that they operate under principles different from those of Special Relativity. This is incorrect. GPS technology actually relies on both Special and General Relativity to function accurately. Time dilation occurs due to both the relative velocity of the satellites (Special Relativity) and the difference in gravitational potential between the satellites and the Earth’s surface (General Relativity). Far from disproving relativity, GPS systems confirm the accuracy of Einstein’s theories. Your claim suggests new transformation equations are necessary to avoid supposed paradoxes in Special Relativity. However, these paradoxes only arise from misunderstandings of how time, space, and velocity transform between different reference frames. The Lorentz transformations, as part of Special Relativity, accurately describe how different observers perceive time and space, ensuring consistency with the experimental evidence, including the constancy of the speed of light. The proposed “correct equations for relativity” based on Galilean transformations cannot explain the behavior of light and are incompatible with the experimental data that led to the development of modern physics. The ideas presented in your claim reflect a fundamental misunderstanding of the principles underlying Special Relativity and overlook the extensive experimental confirmation of Einstein’s theories.
Question, around 51:25 when he shows that the two scaling functions (Lorentz factor) f(v) and g(v) must be equal for the space and time components by saying that when x = ct, x' = ct', doesn't this only show that f(c) = g(c)? x' = (x - vt)•f(v) and t' = (t - vx)•g(v), setting x=t, x'=t', x' = x(1 - v)•f(v) = x(1 - v)•g(v) = t' (1 - v)•f(v) = (1 - v)•g(v) only for the initial assumption v = c. I could construct a similar function (4 - v)•2v = (4 - v)•v² which is only true for v = 2. Also, is the assumption the gamma is only a function of the magnitude of the velocity, and not the vector the assumption that the universe is isotropic?
It is possible to derive 2 contradictory time dilation equations. The first paragraph below describes the situation with Sally aiming a flashlight straight up and down so that Sally sees the light moving straight up and down and John is outside the spaceship and sees the light forming a triangle with the floor of the spaceship. The second paragraph describes Sally aiming a flashlight towards the left while the spaceship moves to the right. Now the situation is exactly reversed. Sally sees the light forming a triangle with the floor and John sees the light bouncing straight up and down. Sally is in a moving spaceship. John is outside the spaceship. Sally is moving to the right at .6c. The height of her spaceship is .8 light-seconds. If Sally has a light clock with the light bouncing straight up and down the light will make a 3-4-5 right triangle from the viewpoint of John. If the change in time for Sally is delta T_o and the change in time for John is delta T then the following equation can be derived: delta T = delta T_o/((1-.6^2)^.5). So .8 seconds for Sally = 1 second for John. Now Sally has a light clock but this time she is holding a flashlight at an angle of 53.13 degrees above the horizontal and pointed to the left. Now the leftward movement of the light exactly matches the rightward movement of the spaceship from John's viewpoint. Now the light is bouncing straight up and down from the viewpoint of John and the light is making a 3-4-5 right triangle from viewpoint of Sally. If the change in time for Sally is delta T_o and the change in time for John is delta T then the following equation can be derived: delta T_o = delta T/((1-.6^2)^.5). So 1 second for Sally = 0.8 seconds for John. The 2 equations are in direct contradiction to each other. Special relativity is falsified.
The first situation is the standard derivation of the time dilation formula. In the second situation the observations of the movement of light are simply reversed from the first situation.
It's a statement of the invariance of the speed of light. The fact that the expression you wrote is the same in any two frames is a statement that the speed of light c is the same in those two frames.
44:00 The 2 in the numerators come from twice the distance between the moving clocks. Since the 2's cancel, the slope v is independent of the units of this value. We could change the distance between the moving clocks and the slope of the line joining the moving clocks at 0 and b would still be v. This shows that the t' = 0 axis passes through b.
One question after watching the first hour.. how was v supposed to be defined? In terms of the stationary reference frame? If so wouldn't the moving frame measure v differently since it measures x t differently?
Let me phrase that better. The point of relativity is that there is no such thing as "the stationary reference frame". What we do instead is we compare two different reference frames, which move relative to each other at a speed v. There is no need to confuse yourself with the fact that x and t are measured differently. It is really a matter of symmetry. S' moves at a speed v relative to S means that the origin in the frame of reference of S, yes measured in x and t coordinates of S, moves at a speed v in the positive x-direction. But clearly, no-one stops you from choosing S' to be the frame that is stationary (i.e like jumping onto the spaceship which is moving relative to the earth), in which case clearly S will move with speed v in the opposite direction-:in your -x' direction. You only begin to worry about x and t being measured differently when you consider TWO events which are separated in space or time. In this case you simply are tracking the origin of the other reference frame.
Lots of people are confused by x + t being a constant, so.. here's an algebraic proof I drew up for those interested. so, a line with that angle has a slope of 1, or -1. In other words, f'(x) = +- 1 so, if we take the antiderivative, we have.. f(x) = +- X + A where A is a constant. so, where the slope is positive, f(x) = x + 1, we can express it as x - t = constant or rather, x - f(x) is a constant. how is this? X - (X + A), or.. X + F(X) = -A -A That's not a variable.. that's a constant. Replace F(X) with t because t is on the y axis there, and you have your answer. meanwhile, X + (-X + A) (negative slope) (X - X) + A A Also a constant.
True, but (x+t) can also be understood as a constant by just sticking to simple intuitive concepts of lines and gradients rather than scrutinizing it with calculus.
If anyone is looking for an easier explanation of special relativity's concepts, I highly recommend VSauce's "Would Headlights Work at the Speed of Light?" video. He has a lot of graphical and animated explanations there, while these lectures involve more mathematical proofs and calculations. I found learning the concepts first and coming back here for the math much easier, especially since I'm doing this before quantum mechanics (standard curriculum teaches QM first).
+RunItsTheCat I would argue that Special Relativity is MUCH easier than QM. And, indeed, at my university special relativity is taught in 1st year whereas QM is taught in 2nd year
+RunItsTheCat First notice that their is an Eter. Thats fact! So no we debunk this shit by the sionist fraud St Einstein. Dayton Miller redid the Michaelsson experiments but 10000 more carefully and did se interaction. To day we see it for Bifeldt Brown , Casmir effect and 100 other things. The EM wave does spread out transversal into Eter with C but the dielectric vawe propagates faster ( Tesla did calculate) . The magnetic propagation vawe never determined at all ! But true they probably are longitudal and thats for study. So no go and study the artifact,, co-rotating magnet and faraday disk for example. If we check two conductors parallell with same vector currents. If you are the "electron" propagating in one conductor and your buddie is in the other conductor moves parallell to you with same speed, do you se any relative movement? No HELL no. You are moving at constant speed and so is your friend. BUT YOU VILL notice that your conductor moves to your friends conductor and the opposite !!!!!!!!! The relativists explains this with circular argument introducing their fraud theory. If we take in an eter you got your relativity but the relativists does not like eter but today they call it dark energi and a lot of other crap. REad Bjerknes book St Einstein pdf at youtube to get why the banksters gaved us this fraud. E = MC2 was known by Maxwell before Einstein was dry behind the ears. The space is working by electricity and birkeland, Tesla and the real physisits did all this finnished together with the guru and legend Hannes Alfvén. The establishment does not wont us to know as they want us to live dumbed down.
Here's something to look at... Ship1 at rest at top: T--------------------N N--------------------T The moment when T of ship1 is lined up with N of ship2 must be the same moment in both frames of reference because there is only 1 moment when this occurs. At this moment for someone at N of ship1 to see T of ship2 they have to look in 2 different directions simultaneously. This is impossible. N of ship1 is simultaneously both passed and not passed T of ship2. This is impossible.
At 1:18, how do we calculate the length of the metre stick calculated by the stationary observer? Do we say when t=0, x^1= 1, and then plug this into the Lorentz transformation? This gives you the expected result, but I'm just really confused...
The point is that any line at this angle can be written as y=-x + c (for some constant c) ... and yes that c intercept is the constant since rearranging gives y+x=c along that line.
![Lp. Сердце Вселенной #60 РОЖДЕНИЕ ЛОЛОЛОШКИ [Финал] • Майнкрафт](http://i.ytimg.com/vi/YoR0pAV9FVQ/mqdefault.jpg)
Imagine getting lectured on special relativity by Prof. Susskind for free, what a time to be alive
For free? Only on yt
Very original comment. I have not read this same comment a million times. Obviously not. Your brain sure comes up with new creative ideas every time. Bravo
@@saimbhat6243 imagine being bitter over seeing many people be grateful for the same thing
@@jesusthroughmary its hard to imagine "jesusthroughmary" actually appreciates the physical science involved. don't you people think the earth was made 6 thousand years ago or something? I'd always figured with folks like that in your community, y'all must not appreciate science very much?
@@lillyclarity9699 and you claim to be educated, what a world
I fell asleep listening to Veritasium and somehow ended up here when I woke up to this.
If Veritasium is an exotic starter, then this is the main course and I'm loving it!
Good Job you.... YT machine learning recomendation engine!!
Me too. How wonderful
Me too. That’s pretty awesome.
always ends up in some kind of stanford lecture for me when i wake up lol. wish i could retain knowledge while i was sleeping.
I fell asleep to professor Dave
I fell asleep watching a philosophy channel and woke up to this lol 🤣
I fell asleep with my phone on and this is what i found, not disappointed
Yeah me too
Same lol.... Leonard Suskind is pretty entertaining
XD
dude same lmao
Me too lol
Thank you Stanford University, having access to these lectures means more than you know. I was an average student in grade school who couldn't pinpoint what direction to follow and now at 28 it's clearer and although the signs have always been there I'm seeing and listening with clearer senses and again I'm so very grateful you have these lectures available for people like me. Education in this world is important more now than ever and I hope you all know how much value you're adding to the world by sharing knowledge. Thank you again so very much. I hope one day to be an official student.
What direction did you choose to follow?
Can u explain what he is saying
Thank you so much to whoever was behind the decision to film these and post them online for free. I'm going through it slowly but it's amazing to have the opportunity to watch these amazing lectures.
Yeah it is
or sum
i wake up every morning, & when my mind is freshest i make a few flashcards. A gentle stream cuts through stone
I use supermemo to stop me from forgetting what i learnt
This is because in the past, i worked through this really nice, gentle big book called Engineering Maths (by KA Stroud). But I forgot a lot of it = it was rather a case of "in 1 ear & out the other". But with Supermemo the knowledge is permanent
@@alwaysdisputin9930 ip
Can u explain it
I cannot think of physics without prof Suskind. It is amazing to see a genius like him teach being humble to the core despite his genius! He is exemplary in every way! God bless him and wish he gets his Nobel Prize which he richly deserves very soon!
I fell asleep watching different ways too cook an omelette and somehow woke up to this. I know I don’t belong here so I’ll see myself out hehe
Hahahaha it's completely the same thing what happened to me rn
How fast was the omelette going, with respect to your reference frame?
get back here, google knows something you dont, it knows you need more quantom physics
I was watching how to make 3d rockets, so i feel i am at least in the same universe, plus i recognise Prof. Suskind
Veritasium - Simplest math problem no one can solve, UA-cam autoplayed this next ... um ok .. sure I suppose I'm ready for this now, after watching that... saved myself thousands on college ..
Countless times i have been studying length contraction
This is the first clear explanation about the meaning of measurement
"No contradiction"
I’ve waken up to this video so many times I’m starting to sort of understand special relativity
Lies again? Special moment
I woke up to this... I'm going to watch from the beginning to make sure I get it right.
What is he explaining
How time gets wacky when you move at high speeds @@Jeremy-fd2pw
I respect professors who go read the original work of scientists and turn it into an amusing lecture. I just enjoyed every second of this video. Thank you very much Sir
Wondering why these kind of lectures help me sleep so well when I came to the ugly realization that it's most likely because it brings me back to a simpler time of... sleeping in class.
Many thanks to Stanford and Prof. Susskind. I've watched a few series, and I really love the way he explains things, in a very logical and simple way. Helped me understand many things that apparently were not as clear as they should have been to me!
Super thanks for making this public. My classes and text barely touch on these concepts. Can't thank you enough.
What is he explaining
Professor Leonard Susskind is one of the fathers of string theory, I am happy to watch this lecture series.
a sahaniss iy mazigh 😀
This is awesome
This first lecture really blew my mind the first time i saw. This isn't gold; it's platinum! Susskind continues to inspire my own teaching, and of course, my study of physics :)
Thank you Dr Susskind. Posting this comment right at the top here as a high school physics teacher. The first 4 lectures are the perfect introduction for my students into special relativity, taught the way it was meant to be taught--straight from Einstein's paper, explained in common language. I show these first 4 videos every year at the end of our units on classical mechanics as a follow-up. The kids love them, and love Dr Susskind. Thank you thank you! Follow up--thank you for our list of Susskind-isms--"time is time is time is time", "derove", and who could forget poor Seymore, out there on his world line all alone waiting for a light ray.
The word "derove" did stand out in my memory but I didn't think of anything wrong with it until I read your comment, haha
What's the difference between this course "Special Relativity" and "Modern Physics: Special Relativity" also by Susskind?
It's actually amazing that working through deriving the way space and time relate to each other under coordinate transformations is extraordinarily clear and makes total sense, as long as the only special assumption is that the speed of light must remained fixed. Also, I've always wondered why Einstein would make that assumption in the first place, but his mention of thinking about Maxwell's Equations also makes total sense. You shouldn't be able to make the electromagnetic field vanish by moving fast enough.
Njjybbh hi ghnkyhhubsw. A
TIME DILATION IS FULLY EXPLAINED, AS THE ULTIMATE MATHEMATICAL UNIFICATION OF PHYSICS/PHYSICAL EXPERIENCE IS CLEARLY PROVEN:
A PHOTON may be placed at the center of what is THE SUN (as A POINT, of course), AS the reduction of SPACE is offset by (or BALANCED with) the speed of light; AS ELECTROMAGNETISM/ENERGY IS GRAVITY; AS E=MC2 IS F=MA. Gravity IS ELECTROMAGNETISM/energy. (The stars AND PLANETS are POINTS in the night sky.) Time DILATION ULTIMATELY proves ON BALANCE that electromagnetism/ENERGY IS GRAVITY, as C4 is a POINT that is ELECTROMAGNETIC/GRAVITATIONAL (ON BALANCE) as SPACE; AS E=mc2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Time DILATION proves that electromagnetism/ENERGY IS GRAVITY, AS E=mc2 is DIRECTLY and fundamentally derived from F=ma. E=mc2 IS F=ma. A planet AND a star thus constitute what is A POINT in the night sky. It ALL CLEARLY makes perfect sense. Gravity IS ELECTROMAGNETISM/ENERGY. ACCORDINGLY, I have ALSO fully explained the MATHEMATICAL UNIFICATION of Einstein's equations and Maxwell's equations (GIVEN THE ADDITION OF A FOURTH SPATIAL DIMENSION); AS E=mc2 IS F=ma. The Sun AND the Earth are F=ma AND E=mc2. Great. SO, ultimately and truly, TIME is NECESSARILY possible/potential AND actual IN BALANCE; AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. AGAIN, time DILATION ULTIMATELY proves ON BALANCE that E=MC2 is F=ma; AS ELECTROMAGNETISM/energy is gravity. Great. Indeed, this NECESSARILY represents, INVOLVES, AND DESCRIBES what is possible/potential AND actual IN BALANCE. (E=mc2 IS F=ma.) Therefore, INSTANTANEITY is thus FUNDAMENTAL to what is the FULL and proper UNDERSTANDING of physics/physical experience; AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. SO, GRAVITATIONAL force/ENERGY IS proportional to (or BALANCED with/as) inertia/INERTIAL RESISTANCE; AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity. Accordingly, the rotation of WHAT IS THE MOON matches it's revolution. MOREOVER, a given PLANET (including WHAT IS THE EARTH) sweeps out equal areas in equal times consistent WITH/AS E=MC2, F=MA, AND what is perpetual motion; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. "Mass"/ENERGY IS GRAVITY. ELECTROMAGNETISM/ENERGY IS GRAVITY. Gravity AND ELECTROMAGNETISM/energy are linked AND BALANCED opposites, AS E=MC2 IS F=MA; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. GREAT !!! It ALL CLEARLY makes perfect sense. BALANCE and completeness go hand in hand. Very importantly, outer "space" involves full inertia; AND it is fully invisible AND black. E=mc2 IS F=ma. "Mass"/ENERGY involves BALANCED inertia/INERTIAL RESISTANCE consistent with/as what is BALANCED ELECTROMAGNETIC/gravitational force/ENERGY, AS E=mc2 IS F=ma; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. (Energy has/involves GRAVITY, AND ENERGY has/involves inertia/INERTIAL RESISTANCE.) E=MC2 IS F=ma. Objects fall at the SAME RATE (neglecting air resistance, of course), AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Gravity IS ELECTROMAGNETISM/energy. E=MC2 IS F=ma. It ALL CLEARLY makes perfect sense. Magnificent !!!
By Frank DiMeglio
This is what you need to know.
THE FULL UNDERSTANDING OF TIME (AND TIME DILATION), AS E=MC2 IS CLEARLY F=MA ON BALANCE; AS ELECTROMAGNETISM/energy is gravity:
INSTANTANEITY is fundamental to what is the FULL and proper UNDERSTANDING of physics/physical experience (in and with TIME), AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity; AS the stars AND PLANETS are POINTS in the night sky. TIME dilation ULTIMATELY proves ON BALANCE that ELECTROMAGNETISM/energy is gravity, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity. (Gravity IS ELECTROMAGNETISM/energy.) THE EARTH/ground AND THE SUN are CLEARLY E=MC2 AND F=ma IN BALANCE, AS the stars AND PLANETS are POINTS in the night sky; AS ELECTROMAGNETISM/energy is gravity. TIME is NECESSARILY possible/potential AND actual IN BALANCE, AS E=MC2 IS F=ma; AS ELECTROMAGNETISM/energy is gravity !!!! TIME dilation ULTIMATELY proves ON BALANCE that E=MC2 IS F=ma, AS ELECTROMAGNETISM/energy is gravity. It all CLEARLY makes perfect sense. Balance and completeness go hand in hand. E=MC2 IS F=ma. This NECESSARILY represents, INVOLVES, AND DESCRIBES what is possible/potential AND actual IN BALANCE, AS ELECTROMAGNETISM/energy is gravity !!! Comparatively, consider the man who IS in outer "space". Great. AGAIN, the stars AND PLANETS are POINTS in the night sky !! AGAIN, TIME DILATION ULTIMATELY proves in what is a BALANCED FASHION that ELECTROMAGNETISM/energy is gravity; AS E=MC2 IS F=ma; AS gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE. Gravity IS ELECTROMAGNETISM/energy ON BALANCE. E=MC2 IS F=ma ON BALANCE !!! NOW, carefully consider that the stars AND PLANETS are POINTS in the night sky !!! Great !!! "Mass"/ENERGY involves BALANCED inertia/INERTIAL RESISTANCE consistent with/as what is balanced electromagnetic/gravitational force/ENERGY, AS E=MC2 IS F=ma ON BALANCE; AS ELECTROMAGNETISM/energy is gravity. It all CLEARLY makes perfect sense, AS BALANCE AND completeness go hand in hand. E=MC2 IS F=ma ON BALANCE !!!
By Frank DiMeglio
UNDERSTANDING TIME AND THE CLEAR MATHEMATICAL PROOF THAT E=MC2 IS F=MA ON BALANCE, AS ELECTROMAGNETISM/energy is gravity:
ELECTROMAGNETISM/energy is gravity. The stars AND PLANETS are POINTS in the night sky. Gravity AND ELECTROMAGNETISM/energy are linked AND BALANCED opposites, AS ELECTROMAGNETISM/energy is gravity; AS “mass”/ENERGY IS GRAVITY; AS E=MC2 IS F=ma. Therefore, the planets will move away very, very, very slightly in BALANCED relation to what is THE SUN. (Also, carefully consider what is THE EARTH.) Great !!! This explains the cosmological redshift AND the “black hole(s)”. GRAVITATIONAL force/ENERGY IS proportional to (or BALANCED with/as) inertia/INERTIAL RESISTANCE, AS E=MC2 IS F=ma ON BALANCE; AS ELECTROMAGNETISM/energy is gravity. Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS E=MC2 IS F=ma ON BALANCE; AS ELECTROMAGNETISM/energy is gravity. Gravity IS ELECTROMAGNETISM/energy. “Mass"/ENERGY involves BALANCED inertia/INERTIAL RESISTANCE consistent with/as what is BALANCED electromagnetic/gravitational force/ENERGY, AS E=MC2 IS F=ma ON BALANCE; AS ELECTROMAGNETISM/energy is gravity. SO, the rotation of WHAT IS THE MOON matches it's revolution; AND objects fall at the SAME RATE (neglecting air resistance, of course) !!! Time dilation ULTIMATELY proves ON BALANCE that E=MC2 IS F=ma, AS ELECTROMAGNETISM/energy is gravity !!! It all CLEARLY makes perfect sense, AS BALANCE AND completeness go hand in hand. Balanced inertia/INERTIAL RESISTANCE is fundamental. Time is NECESSARILY possible/potential AND actual IN BALANCE, AS E=MC2 IS F=ma ON BALANCE; AS ELECTROMAGNETISM/energy is gravity !!! GREAT. Stellar clustering ALSO proves ON BALANCE that E=MC2 IS F=ma, AS ELECTROMAGNETISM/energy is gravity.
By Frank DiMeglio
@@frankdimeglio8216 Speed of light being constant in al frames I believe Einstein learned from the Michelson-Morley Experiment into the luminiferous ether.
I can only say that prof Suskind is one of his kind and I feel I am really privileged to hear him speak and teach physics. He is a real genius!
this video is amazing. Truly easy and fundamental. Thank you so much for the upload. Much appreciated. And professor Susskind, I must say that I am a big fan!
Great lecture. What I really miss in all those lectures are examples. Examples with numbers. The course would take twice as much time, but the number of people who understood would increase much more. I know it; I do lectures on much less complicated technical subjects, and as soon as you come from theoretical equations to practical use, it can be seen how many students get enlightened. Covariant and contravariant vector, show the transformations - 2 dimensions would be enough.
Wow, this prof is really good. Never in my lifetime I can get to be lectured on Can'tafford university. XD
Jers N thats Leonard Suslikin (excuse the spelling ) the father of string theory, hes very famous
can anyone tell me what is x prime i didnt understand it
It's the spatial coordinate of the moving reference frame. 13:58
Enter the Braggn' False
If you think he is good, I wonder what kind of teachers you have had.
This is a God sent seriously. Been reading through three books today and a lecture discussing the same topics u talked about in the first 11 minutes. Yours made so much sense - I really appreciate all the chronological science history as you teach. So many leave the little things out.
I have always had trouble thinking about relativity and this really helped me in starting to wrap my head around it
And, so did you notice any corresponding change in your relations with special relatives? 🤔
@@woodpeckery starting to understand them better as well
@@woodpeckery LMAO
What is he talking about
I watched this, well more like tried to watch this right before I started my bachelors in Astrophysics a couple years ago. I was beyond lost. Now after a couple years under my belt, it makes so much sense now. I love the way he teaches this topic.
Wow. when he got to the lorenz transformations I was just blown away. I had seen this before but seeing how einstein actually worked this through... it gave me chills. a true legend. thank you prof susskind.
Yeah, I read somewhere that Einstein's method was like climbing the hill from a very steep path where there is a less steep one available (now).
@@zombiesalad2722 I heard the same thing from minutephysics.
The funny thing is, if you know absolutely nothing about physics, you can discover SR all by yourself. Sadly, most folk have been trained to think that this is not the case at all, even though a high school dropout can do it.
@@new-knowledge8040 yes for sure only if he has the same level of boldness as sir Einstein to declare time is not absolute:)
Zabzazim
This knowledge is so valuable. It was so difficult to find a lecture that used this simple method of plotting these quantities on a Cartesian plane. That makes it so much easier to see how all these quantities relate. Sure, it is a longer video than you find on some of the pop science channels that are popular. But an investment of a hour is more than worth it. The attempts to gloss over this step on popular videos might make the video get more plays and likes. But it shorts the viewer on the necessary steps.
❤Precisely . Those steps require real care.
Im using these videos to fall asleep too to hopefully learn something and get smarter the same way i learnt every word to every song i use to sleep
UA-cam knows me well. Fell asleep watching a Jon Stewart interview, woke up to this… luckily I am passingly familiar with physics and relativistic physics so, I quite enjoyed this and was unable to go back to sleep.
This is great! I am in the equivalent of last year of high school and love watching university lectures of subjects I have in school. Having a proper explanation of these concepts makes understanding the analogies we’re fed in school a lot more digestible. Can’t wait for University next year!
Wow ur cool
I'm a freshman undergraduate student. There would be no way I was going to pass the first semester exams if not for lectures on physics from mit and Stanford. In my university, they barely explain this stuff and expect you to already know/understand it anyway
I just want to thank you, Stanford University, for uploading these lectures. awesome info here!
@@agiarusso keep your kinda cool babe babe I miss know knew it I y hmm Nakul good jkk
@@darkmemer6663 mmm
These special relativity lectures, and the whole series of physics courses of which they are a part, are excellent. Susskind's explanations are very thorough. Thanks to them, I understand the material better than I did when I was a physics major 40 years ago. He does occasionally slip up with minus signs, but this gives you the opportunity to redo the derivation and figure out where the slip occurred, where doing this definitely helps you learn the material better.
Rather, the idea is based on an error in logic:
_"The 2 photons will have been sent simultaneously only if they arrive simultaneously at the midpoint, therefore if they arrive simultaneously at the midpoint then they will have been sent simultaneously."_
That is, "if p then q, therefore if q then p".
This is a formal fallacy in propositional logic, called "affirming the consequent".
The truth of the matter is that the photon at B is fired later than the photon at the origin, and this because it has to travel a shorter distance in order to arrive at A at the same time as the photon from the origin arrives at A. And so we see from the chart that B is at t>0.
So there is only 1 time scale, t, for you can't have a moving system of clocks and have those clocks not tick. Clocks tick. That's what they do.
So t' is only 0 along the x axis, which is where (and when) the first photon is fired, for the first photon is fired at the origin and at the origin t' is on the x axis. After that, t' is greater than 0, because its clocks are ticking. And so t' is synonymous with t, and therefore superfluous: we only need t.
The problem is that the issue is not really a physics issue, but a logic issue. Physicists are not necessarily good at logic. Logic is a different skill.
If you wish to see how SRT is errant at its very first derivational step, just search "Nullification of Relativity Theory via the Sufficiency of the Galilean Velocity Transformation", click on the viXra link, and then click on v2 of the PDF.
@@lawrence1318 yea, dude, I'm sure you're right and physicists are wrong.
Fred = Leonard
28:45 _"My friends who are separated by equal distance: there's me, the 1 in front of me & the 1 in front of him"_
30:52 _"Let's give these people names: Fred, Anne..._
_& See More"_
Below is an attempt at calculating how many people go on to complete all the lectures.
As of July 15, 2021, here are the stats for the views and likes for the 10 videos in this series:
Lecture 1: 897024; 6.7k
Lecture 2: 212144; 1.2k
Lecture 3: 225383; 1.2k
Lecture 4: 139619; 779
Lecture 5: 99385; 543
Lecture 6: 80824; 512
Lecture 7: 65712; 478
Lecture 8: 67962; 480
Lecture 9: 74709; 464
Lecture 10: 71365; 508
Around 900k people watched the first video, and 6.7k liked it. 71k watched the last video, and 508 liked it. As a rough first approximation, at most around 8% of the viewers who watched the first video might have gone on to complete all the lectures.
YOU ARE LEGENDS. THANK YOU FOR THE VIDEO LECTURES. Forever in your debt.
Grateful.
Sahi bole bhaai...Gajab hai ye to
@@physicsevolutionandscope9588 hi indian
@@jeeaspirant2016 vwcevqvqvqvvvgeb lkkkjjjjjjjjjjjpoppjjppojppjojopjkjjjjkkmkkkmkkkkkmllllmllmmmlmkllllllllllllmlmlmlmmlkllklkkllllllklkmllmmmlmlmkkkkkkkllpmlppmpllllllllllllklklmpllllllpmllkklllllllkllklkklllkllllllpkllkllkllklllpllklllmkkmlkllllllkllppkkllklkllllkkklllllllkkkkllllllkmppplllkkpllklmlkllllllkkmlkklllklkkllklkmkkkllllllklkllmklfffffg
At 1:27:25, it shows t is dilated when t'=1 from the view point of moving frame, but t' is contracted from the view point of the rest frame. For example t=1, x=1 are both contraceted in the moving frame to sqrt(1-v^2). Time and space are both contracted in the moving frame. Contraction of time is slowing down of the clock, i.e. dilation of time.
Give this man a nobel prize for teaching
I beg you please to allow for at least auto-generated subtitles to be turned on, so I can share this with Spanish speaking friends.
NOPE, sorry but your friends are not allowed to synchronize their watches with any X’s, V’s, or T’s. It's just not possible, I'm sorry.
@@TheOGC4 si
Every time when I have class about special relativity, I consider myself taking philosophy.
Lol, that was funny. But on a serious note, the barrier is indeed high but once you cross it, it makes perfect sense.
@@aloknathsingh4647 thx bhai how long is is taking you? maths in sr very simple for me but concepts in problems is very hard
Alok Nath Singh The problem is that’s wrong. The first postulate is impossible.
Approaching philosophical questions happens all the time with Sean Carrol biggest questions in the universe, Cosmology beginning of universe and black holes. Sean Carroll is another great explainer.
@@HughesMath1 🔹°= -🔹🚽❓♓/t-2.Special relativity x y and z.Transfers and rotations.Spacial set of coordinates.Thank you thinking out loud use of objective units.Yipes,my coordinates are different from your coordinates.I end up apologizing to someone.Is it year of the Ox yet?
There are professor's who are born to lecture, and he's one of them. Amazing. The way interacts, asks questions during the problem solving he's awesome
I shall watch this particular lecture regarding Lorentz Transformations. This Is amazing lecture by an amazing teacher. Dr. Susskind.
I have seen this type of work from renowed teachers but the way Einstein himself have done and explained by this sir was absolutely great....thanks for making it understandable
If I could meet Einstein, I’d bring him the best strongest coffe I could get, and just sit back and see what happens, science!!
This is one of my favorite topics! Thank you so much!
Tell me what he's explaining
At 1:02:25, the equations of lorents transformation has a domain of all real numbers except for v=1. The equations derivation, however, depends on x=t when v = 1. Refer to the video at 50:34. Isn't it a big contradiction? Trying to explain the equations when v = 1 seems to be completely meaningless.
v= 1 condition is meaningless as nothing can travel with the velocity of light for now. it should be less than that
All flowed over my head but I am glad that I watched this anyway
1:04:35 - since t=vx (44:36), t'=(t-vx)/√(v/c)=0, contrasting with the answer later of t'=t ! How to explain it?
The math in this lecture is beautiful, e.g slope of line 0‾b = v (44:25) 👍
33:20- this is the foundation of the following contents, wish have spent more time on it.
t=(v/c^2)x is a the line depicting simultaneoty in different frames of reference
The slope was v/c^2 as he said later
I think I will subscribe to this channel, thank you for putting out free education.
I wonder has my brain learned something of these lectures all the time I have listened to these while sleeping 😂
Just reading his new book “Special Relativity and Classic Field Theory”
NO KIDDING! YOU KNOW, I WAS THINKING THE SAME THING! IF I WERE TAKING A CLASS I WOULD HOPE TO GET SOMETHING OUT OF IT.( REGURUTATINE. IS IT WHAT I AM PAYING 4. SOME1 HAS TO TEACH A CLASS BASED ON EVERYONE ELES'S HISTORY BOOK BULLSHIT! HOW MANY TIMES DO I HAVE TO SIT IN A CLASS WONDERING? WHEN ARE YOU GOING TO TEACH ME SOMETHING? YES, YES. I HAVE HERD ALL OF THAT BULLSHIT BEFORe. FUCK! I COULD WATCH THAT ON THE DISCOVERY. HISTORY CHANNEL. LOLOLOLOLOLOL JUST( AMGEN ) ALL OF THE MONEY THAT I COULD SAVE!!! WOW!!! THAT IS FUCKING AMAYZZZZZING. P.S. LOOK AT( AMERICA IS NOT THE GREATESt CONTRARY) WE NEED TO WAKE UP PEOPLE. BECAUSE I DON'T LIKE BEING 2ND BEST!!!!!!!!!!!!!!!!!!!!!!!!
@@robbyandrews6318 you're an intellectual
unrelenting awesomeness haha
Godammm. How right that You are. Lol.
CLASSIC FIELD. YOU DO MEAN OR IS THAT WITH AN I? CLASSIC POS. TELL YOU WHAT HUNNY. IF YOU ARE THAT GOOD. LEAVE ME A MESSAGE. WHEN YOUR N- PHYSICS IS BETTER THAN MINE. PLEASE CALL ME!! I CAN'T FUCKING WEIGHT. M-0 G-0. Know if EYENSTIN. DID I SPELL THAT WRONG. TELL ME THEN. WHAT WAS HIS UP TAKE ON HYGIENE. YESTERDAY'S BULLSHIT.
Thanks Stanford, and Dr Susskind for these great lectures! Never had the chance to take relativity.
Very good! Thank you Stanford.
Sorry about my battery it’s ran on faux loc for ahead bandwidth 22:21
I wish I could hear the audience questions. For that matter, closed captions would help, too.
use headphones
It's a very interesting lecture. However I can't understand is why at 47:17 did he put x' = (x - v*t)*f(|v|). Actually there is no obligation to put such equation. From a general perspective we can simply put x' = h(x,t,v) and h = 0 when x = v*t. If someone understood why he made such an assumption, I'll be glad to hear the explanation :) Thanks !
why everyone is falling sleep and waking up here ?
36:18 I really don't understand where the "x + t = constant" bit comes from. Everything else in this lecture makes sense, but I don't get where he came up with that property. Could someone help me understand? Thank you.
That's the equation of light going the "other" way (we have only one direction, the x axis, so we can talk about light going forward and backward in a certain reference frame).
The equation for a light beam going forward is x = d+t (so the slope is 1, the speed of light; d is a constant representing when the light beam is at position x=0). In the case of the lecture, d is 0, so the equation is x = t.
The equation for a light beam going backwards is x = d-t (d has the same meaning as above, but slope in this case is -1) => x+t = d (a constant)
Hope you understand now! :)
+Veridian x + t is a constant because.. well I'll give a quick proof actually.
so, a line with that angle has a slope of 1, or -1.
In other words, f'(x) = +- 1
so, if we take the antiderivative, we have..
f(x) = +- X + A
where A is a constant.
so, where the slope is positive, f(x) = x + 1, we can express it as x - t = constant
or rather, x - f(x) is a constant.
how is this?
X - (X + A), or..
X + F(X) = -A
-A
That's not a variable.. that's a constant. Replace F(X) with t because t is on the y axis there, and you have your answer.
meanwhile, X + (-X + A) (negative slope)
(X - X) + A
A
Also a constant.
I love this man... going to be a very sad day when he departs us!
@DeeJay1210 Pretty sure he means when he retires mate.
What he talking about
This man is so well spoken and looks great... don't know why I felt the need to say that.
Esteemed professor
Yes Galileo did write about
Wonderful pages about a moving ship
Train did not exist yet at his age
Thanks
1:06:26 If anyone else is confused about why V on top is divided by C^2 as opposed to C: V and X are both proportional to the value of C. V/C*X/C == V/C^2*X.
thnk you for clearing the doubt
More humor at 1:23:00. That Rolex watch from New York stole the show. This was an excellent lecture, professor. :)
Try 1:44:00 too. 'Derove'... ;)
Around the 30.30 minute mark, you indicated that a stationary mover would move along the x-axis but in reality, the stationary observer would stay at x=0 but move up the time axis. The time changes for the stationary observer but not the spatial extent. Or am I missing something.
'We DEROVE the invariant!'- luvvv the guy!
Shut up
"In May and November, the Earth is moving at "right angles" to the line to Algol. During this time we see minima happening regularly at their 2.867321 day intervals. However, during August, the Earth is rapidly moving towards Algol at about 107,229 km/hr as explained on my How Fast Are We Moving? page. (The Earth moves approximately 202 times its own size in one day.) So in 2.867321 days the Earth moves about 7,379,039 km closer to Algol. _But the varying light from Algol doesn't know this - its light waves left Algol 93 years ago and are travelling at a constant speed._ The result - we "catch a bunch of minima early" during August as shown on Chart 2. Exactly the opposite happens during February - the Earth is moving away from Algol that fast and it takes longer for the group of minima to reach us so we see them taking longer between events. How long? 7,379,039 km divided by the speed of light 299,792.458 km/sec is 24.61382 seconds. So in May and November when we are not moving towards or away from Algol - the period seems constant. It is our rapid movement towards or away from the events in August and February that causes the timing differences."
I assume that light is passing the earth at c when the earth isn't moving towards or away from Algol.
In February the earth is moving away from Algol and the time between the eclipses is 2.8675875347 days and the light is passing the earth at 186,265 mi/sec.
In May and November the earth is not moving towards or away from Algol and the time between eclipses is 2.867321 days and the light is passing the earth at 186,282 mi/sec.
In August the earth is moving towards Algol and the time between eclipses is 2.8670608912 days and the light is passing the earth at 186,299 mi/sec.
Amazing. I hope I can take it until lecture 10.
CONCERN SUMMARY: What is the Symmetry assumption motivation?
DETAILS:
At the point where we found:
x'=(x-vt)f(v)
t'=(t-vx)f(v)
To find f(v), since "who is to say which frame is moving", we (Einstein) make the assumption that you can't determine, so they should be symmetric, so:
x=(x'+vt)f(v)
t=(t'+vx)f(v)
hence we can now find f(v)
But what is the motivation behind that assumption? What is the exact motivation for ruling out the possibility that there is an absolute speed for observer 1 and observer 2 with respect to something?
1) "But what is the motivation behind that assumption?": I suppose that you are referring to suddenly these two equations appeared x=(x'+vt)f(v) t=(t'+vx)f(v).
Answer: You don't need more assumptions than these two equations and the fact that any referential see light with the same velocity. For this absolute speed, in both equations ,we must have: x^2 + y^2 + z ^2 = c^2 * t^2 and x'^2 + y'^2 + z'^2 = c^2 * t'^2 (Equations for some light beam starting in t= 0, at the origin, in the two frames.). The movement is in one direction so: let's assume y = y' and z = z' ( these two coordinates won't interfere in the derivation, you can assume different (y,y'), (z, z') and the same result would appear). So, now we have : x^2 - c^2 * t^2 + c^2 * t'^2 - x'^2 => x^2 - x'^2 + c^2 * ( t'^2 - t^2) = 0. Now substitute x' by x'=(x-vt)f(v) and t' by
t'=(t-vx)f(v), and remember that this must always be true, so force to be an identity for x and t. You will get the transformations from there.
2) What is the exact motivation for ruling out the possibility that there is an absolute speed for observer 1 and observer 2 concerning something? :
My answer: any observer can determine speed in their referential. They only need to measure space and time. If you can't determine velocity in your referential, this whole discussion is pointless. For me, he blundered at this point. You don't need to consider relative velocity between these two frames. You can derive the relative velocity from the transformation.
3) In my perspective, there are many leaps of ideias. For example, These two equation x'=(x-vt)f(v)
t'=(t-vx)f(v), come from the fact that x' is invariant in lines x = vt + k ( because, for any observer with velocity v determined by observer 1, in their frame, they don't distance from each other) and t' is invariant in lines t = vx/c^2 + k (this derives from the definition of simultaneous event from Einstein) ( Here I'm not considering c = 1, but you can).
You just need to see that lines t = vx+ k (In observer 1 referential) (I returned with c = 1) have the same t' (Each one with a different t', but in the same line t' is the same). So this lines are the level curve for the function t'(x,t) and then we have t'(x,t) = (t -vx) * f(v). The same can be said for x'(x,t) = ( t -vt) * f2(v) relative to lines x = vt + k. See one thing: x = vt + k => k = x-vt. k is a constant for the line that denominates the linear coefficient. So, for some k : x'(x,t) = (t-vt) * f2(v) => x'(x,t) = k * f2(v). For a given v and k, x'(x,t) is a constant.
He looks like Mike from Breaking Bad
lol true
He looks like a mix between John Malkovich and that guy lol
oh man..that's him!!!!
I was thinking the same thing.
For me he looks like Jacque Fresco
There are different ways to think about this problem. And the scenario used @ 33:10 to explain the dynamics makes it simpler.
Clocks and lengths do not actually change in YOUR frame or reference when you are moving. They only appear to in somebody's else frame of reference that is stationary relative to yours. And Visa a Versa..
You have not understood special relativity
@@Banjo-ed5vv More than you, really
@@HilbertXVI I have a big shlong that's all mate
At 1:15:50, we found using Lorentz transformation that the length of a stationary meter scale measured from a moving reference frame is contracted by a factor of sqrt(1-v^2). But in the space-time plot the length of meter scale from x'=0 to x'=1 along the x' axis appears to be greater than 1 (from basic geometry). What am I missing here?
Ok, so he spoke about it later in the lecture.
“If Einstein is right”… that statement alone transforms this into a philosophy class alas to run with it is mind-boggling.
Both of you go sip some fucking tea
Here is the problem with Special Relativity. Suppose that there is a clock in a flying airplane. Einstein says this about that clock. "The time which elapses between two strokes of the clock is not one second, but 1/sqrt(1-v^2/c^2) seconds, a somewhat larger time. As a consequence of its motion the clock goes more slowly than when at rest." (Relativity, the Special and General Theory, A. Einstein, p.44)
x'=(x-vt)/sqrt(1-v^2/c^2)
y'=y
z'=z
t'=(t-vx/c^2)/sqrt(1-v^2/c^2)
inverse equations
x = (x' + vt')/sqrt(1-v^2/c^2)
y = y'
z = z'
t = (t' + vx'/c^2)/sqrt(1-v^2/c^2)
These equations do not agree with reality because they show that the speed of the airplane is the same as observed from either frame of reference. v is the speed of the airplane and is the same speed as calculated from the time of either clock. We common people live in something called reality where if the pilot of the airplane has a slower clock to time the flight of the airplane, he will get a faster speed for the airplane than an observer on the ground will get using a faster clock on the ground to time the flight of the airplane. What the above equations describe is a miracle, a supernatural event. Here are the correct equations for relativity.
x'=x-vt
y'=y
z'=z
t'=t
These equations are called the Galilean transformation equations and are the equations that scientists used until 1887 when the Michelson-Morley experiment took place, and scientists found that they could not describe the results of that experiment using the Galilean transformation equations. The problem they encountered was that if t'=t, then the two equations that would show the same speed of light in both frames of reference, x=ct and x'=ct', could not both be true because x and x' were not the same distance unless v=0.
But Newton and Galileo were both capable of working simple algebra. If there is a clock in the airplane that shows some other time than t, the time of a clock in the frame of reference at rest. Either of these two earlier scientists could have described a clock with a different rate. They would have just used a different set of Galilean transformation equations with different variables for velocity and time. So if there is a clock in the airplane that is slower than a clock on the ground, then the inverse equations would be
x = x' - (-vt/n')n'
y = y'
z = z'
n = n'
where n' = is the time of the slower clock in the airplane, and (-vt/n') is the velocity of the airplane according to the time of the slower clock on the airplane. These equations describe relativity, not only for a slower clock such as Einstein describes in his Special Theory of Relativity, but also for a faster clock such as scientists say they encounter in a GPS satellite. So to describe light as traveling at c=186,000 miles per second in both frames of reference according to clocks in those frames of reference, we do not say x=ct and x'=ct', as Einstein said, but x=ct and x'=cn' the times of the two clocks in question. We have now resolved the problem scientists could not solve in 1887 without resorting to length contractions, curved space, or other miracles that have been used by scientists since that time. Scientists, of course, are not going to like this because they are paid trillions of dollars by governments to say that Einstein's description of relativity is correct.
SRT = Doppler effect;-)
Nothing else;-)
@@hollaadieewaldfeee It is not relativity. I can tell you that much. It sets up time as some kind of force that controls space. Why would the rate of transitions of a cesium atom on an insignificant planet be the controlling force for all other things in existence?
You start by quoting Einstein and then attempt to argue that the time dilation predicted by Special Relativity leads to contradictory or miraculous results when considering the speed of an airplane from different reference frames, but your claim is riddled with misunderstandings. Here are the breakdowns of your argument.
Time Dilation and Reference Frames:
Einstein’s equations for time dilation, such as t'=(t-vx/c^2)/sqrt(1-v^2/c^2), do not suggest a contradiction or supernatural event. They describe how time passes differently for observers in different inertial frames moving relative to each other. The key point is that each observer measures time and space according to their own reference frame. An observer on the ground and an observer on the airplane will each measure different times and distances, but these differences are consistent when transformed between frames using the Lorentz transformations.
Relative Velocity Measurement:
Your claim also asserts that the speed of the airplane should be perceived differently by the pilot and an observer on the ground due to differing clock rates. However, Special Relativity already accounts for this by incorporating the concept of time dilation and length contraction. The velocity of the airplane is the same in both frames because it is a relative velocity, not an absolute one. What changes between the frames is not the speed of the airplane itself, but the measurement of time and distance.
The idea that a slower clock on the airplane should result in a higher calculated speed in that frame is incorrect because it fails to consider that the distance measured in the airplane’s frame (due to length contraction) would also differ. Special Relativity shows that both time dilation and length contraction ensure the speed of the airplane remains consistent across all inertial frames.
Galilean vs. Lorentz Transformations:
Your claim also suggests reverting to the Galilean transformation equations as a solution. However, this approach overlooks why Lorentz transformations replaced Galilean transformations in the first place. Galilean transformations assume that time is absolute and the same for all observers, which fails to explain the results of the Michelson-Morley experiment, which showed that the speed of light is constant in all inertial frames.
The Lorentz transformations provide the correct relationships between time and space for observers in relative motion. These transformations are not arbitrary or miraculous; they are a necessary consequence of the principles that the speed of light is the same in all inertial frames and that the laws of physics are invariant under changes in reference frames.
GPS Satellites and Relativity:
Your claim also references GPS satellites, suggesting that they operate under principles different from those of Special Relativity. This is incorrect. GPS technology actually relies on both Special and General Relativity to function accurately. Time dilation occurs due to both the relative velocity of the satellites (Special Relativity) and the difference in gravitational potential between the satellites and the Earth’s surface (General Relativity). Far from disproving relativity, GPS systems confirm the accuracy of Einstein’s theories.
Your claim suggests new transformation equations are necessary to avoid supposed paradoxes in Special Relativity. However, these paradoxes only arise from misunderstandings of how time, space, and velocity transform between different reference frames. The Lorentz transformations, as part of Special Relativity, accurately describe how different observers perceive time and space, ensuring consistency with the experimental evidence, including the constancy of the speed of light. The proposed “correct equations for relativity” based on Galilean transformations cannot explain the behavior of light and are incompatible with the experimental data that led to the development of modern physics.
The ideas presented in your claim reflect a fundamental misunderstanding of the principles underlying Special Relativity and overlook the extensive experimental confirmation of Einstein’s theories.
Isn't this guy Mike from Breaking Bad?
lmao thats 1st thing i thought of too
with some john malkovic vibes
Question, around 51:25 when he shows that the two scaling functions (Lorentz factor) f(v) and g(v) must be equal for the space and time components by saying that when x = ct, x' = ct', doesn't this only show that f(c) = g(c)?
x' = (x - vt)•f(v) and t' = (t - vx)•g(v), setting x=t, x'=t',
x' = x(1 - v)•f(v) = x(1 - v)•g(v) = t'
(1 - v)•f(v) = (1 - v)•g(v) only for the initial assumption v = c.
I could construct a similar function (4 - v)•2v = (4 - v)•v² which is only true for v = 2.
Also, is the assumption the gamma is only a function of the magnitude of the velocity, and not the vector the assumption that the universe is isotropic?
I would be highly grateful if english auto generated subtitles would be provided for this playlist
It is possible to derive 2 contradictory time dilation equations. The first paragraph below describes the situation with Sally aiming a flashlight straight up and down so that Sally sees the light moving straight up and down and John is outside the spaceship and sees the light forming a triangle with the floor of the spaceship. The second paragraph describes Sally aiming a flashlight towards the left while the spaceship moves to the right. Now the situation is exactly reversed. Sally sees the light forming a triangle with the floor and John sees the light bouncing straight up and down.
Sally is in a moving spaceship. John is outside the spaceship. Sally is moving to the right at .6c. The height of her spaceship is .8 light-seconds. If Sally has a light clock with the light bouncing straight up and down the light will make a 3-4-5 right triangle from the viewpoint of John. If the change in time for Sally is delta T_o and the change in time for John is delta T then the following equation can be derived: delta T = delta T_o/((1-.6^2)^.5). So .8 seconds for Sally = 1 second for John.
Now Sally has a light clock but this time she is holding a flashlight at an angle of 53.13 degrees above the horizontal and pointed to the left. Now the leftward movement of the light exactly matches the rightward movement of the spaceship from John's viewpoint. Now the light is bouncing straight up and down from the viewpoint of John and the light is making a 3-4-5 right triangle from viewpoint of Sally. If the change in time for Sally is delta T_o and the change in time for John is delta T then the following equation can be derived: delta T_o = delta T/((1-.6^2)^.5). So 1 second for Sally = 0.8 seconds for John. The 2 equations are in direct contradiction to each other.
Special relativity is falsified.
What is he talking about
The first situation is the standard derivation of the time dilation formula. In the second situation the observations of the movement of light are simply reversed from the first situation.
No book has shown that why (ct)^2 - (X^i)^2 is the length element. They just say it is because of invariant purpose.
It's a statement of the invariance of the speed of light.
The fact that the expression you wrote is the same in any two frames is a statement that the speed of light c is the same in those two frames.
Time stops at velocity=c. He covers this toward the end of the lecture while discussing time-like and space-like intervals. Watch at around 1:45:00.
these lectures are so valuable
44:00 The 2 in the numerators come from twice the distance between the moving clocks. Since the 2's cancel, the slope v is independent of the units of this value. We could change the distance between the moving clocks and the slope of the line joining the moving clocks at 0 and b would still be v. This shows that the t' = 0 axis passes through b.
Okay professor
Can anyone tell me in which of his lectures he teaches spacetime diagrams?
At 48:03, x' = x - vt could be incorrect, so add f(v) to the right of the equation, interesting.
One question after watching the first hour.. how was v supposed to be defined? In terms of the stationary reference frame? If so wouldn't the moving frame measure v differently since it measures x t differently?
v is just the relative speeds between the reference frame.
There is no such thing as a stationary reference frame. You arbitrarily choose a reference frame and call that stationary.
Let me phrase that better. The point of relativity is that there is no such thing as "the stationary reference frame". What we do instead is we compare two different reference frames, which move relative to each other at a speed v. There is no need to confuse yourself with the fact that x and t are measured differently. It is really a matter of symmetry. S' moves at a speed v relative to S means that the origin in the frame of reference of S, yes measured in x and t coordinates of S, moves at a speed v in the positive x-direction. But clearly, no-one stops you from choosing S' to be the frame that is stationary (i.e like jumping onto the spaceship which is moving relative to the earth), in which case clearly S will move with speed v in the opposite direction-:in your -x' direction.
You only begin to worry about x and t being measured differently when you consider TWO events which are separated in space or time. In this case you simply are tracking the origin of the other reference frame.
Okay 👌👍
I'm always waking up to this guy
Thanks a million times for the video, but could the camera man be less active and be more static throughout the lecture? I'm feeling dizzy..
Too many shifts in reference frames!
first of Susskind's videos that I feel I'm ahead of... that's a first.. wish I had started here:)
How he arrived at the conclusion that the f() was commutative and used that property in solving for f()? 56:59
+Thomas White if x = x*C. Then C = 1.
So (1-v^2)*f^2 = 1.
f^2 = 1/(1-v^2)
f = 1/sqtr(1-v^2). sqtr(1) = 1
Bro, I'm being haunted by the same question. Have you been able to find a convincing answer yet?
how to enable subtitles? thanks I am deaf
Subtitles don't work with this lecture. Try MIT Opencourseware Relativity where they work. Just click the CC on the bottom
thanks
on youtube i dont find MIT Opencourseware Relativity.. do you have a link?
ocw.mit.edu/index.htm
ocw.mit.edu/courses/physics/8-04-quantum-physics-i-spring-2013/lecture-videos/lecture-1/
Lots of people are confused by x + t being a constant, so.. here's an algebraic proof I drew up for those interested.
so, a line with that angle has a slope of 1, or -1.
In other words, f'(x) = +- 1
so, if we take the antiderivative, we have..
f(x) = +- X + A
where A is a constant.
so, where the slope is positive, f(x) = x + 1, we can express it as x - t = constant
or rather, x - f(x) is a constant.
how is this?
X - (X + A), or..
X + F(X) = -A
-A
That's not a variable.. that's a constant. Replace F(X) with t because t is on the y axis there, and you have your answer.
meanwhile, X + (-X + A) (negative slope)
(X - X) + A
A
Also a constant.
True, but (x+t) can also be understood as a constant by just sticking to simple intuitive concepts of lines and gradients rather than scrutinizing it with calculus.
Waddia S. Agreed! I think that's a great way to think of it. This is just for those who have difficulties with intuition in mathematics :3
If anyone is looking for an easier explanation of special relativity's concepts, I highly recommend VSauce's "Would Headlights Work at the Speed of Light?" video. He has a lot of graphical and animated explanations there, while these lectures involve more mathematical proofs and calculations. I found learning the concepts first and coming back here for the math much easier, especially since I'm doing this before quantum mechanics (standard curriculum teaches QM first).
+RunItsTheCat I would argue that Special Relativity is MUCH easier than QM. And, indeed, at my university special relativity is taught in 1st year whereas QM is taught in 2nd year
+RunItsTheCat First notice that their is an Eter. Thats fact! So no we debunk this
shit by the sionist fraud St Einstein. Dayton Miller redid the
Michaelsson experiments but 10000 more carefully and did se interaction.
To day we see it for Bifeldt Brown , Casmir effect and 100 other
things. The EM wave does spread out transversal into Eter with C but
the dielectric vawe propagates faster ( Tesla did calculate) . The
magnetic propagation vawe never determined at all ! But true they
probably are longitudal and thats for study. So no go and study the
artifact,, co-rotating magnet and faraday disk for example. If we
check two conductors parallell with same vector currents. If you are the
"electron" propagating in one conductor and your buddie is in the other
conductor moves parallell to you with same speed, do you se any
relative movement? No HELL no. You are moving at constant speed and so
is your friend. BUT YOU VILL notice that your conductor moves to your
friends conductor and the opposite !!!!!!!!! The relativists explains
this with circular argument introducing their fraud theory. If we take
in an eter you got your relativity but the relativists does not like
eter but today they call it dark energi and a lot of other crap. REad
Bjerknes book St Einstein pdf at youtube to get why the banksters gaved
us this fraud. E = MC2 was known by Maxwell before Einstein was dry
behind the ears. The space is working by electricity and birkeland,
Tesla and the real physisits did all this finnished together with the
guru and legend Hannes Alfvén. The establishment does not wont us to
know as they want us to live dumbed down.
Zekerias Varg "Quality trolling"
+Alter Kater Nature was my teacher.
+Alter Kater "bullshit" that you cant debunk.
I fell asleep on my phone watching UA-cam last night, woke up hearing this guy 57 minutes into some lecture
same lol
Says that he's not going to get in depth about inertial frames of reference..... *begins explaining inertial frames of reference* LOL
A physicist going in depth and a layman going in depth are two different frames of reference. For the former you're gonna see a ton of math.
Yea, he's done that a few times in the previous two courses. Always a good laugh.
He said he's not going to get into the PHILOSOPHY
@@samuelson4244 4r4 ⁵I 5⁵545rrrrr=rrrr5r5r⁵⁵rr5⁵r5r56⁵really bad ⅚54th 54th 54th ⁵is the 54th ⁵that ⁵is 4555⁵⁵5 r⁵that can make 4554⁵for 45⁵or n.
Here's something to look at...
Ship1 at rest at top:
T--------------------N
N--------------------T
The moment when T of ship1 is lined up with N of ship2 must be the same moment in both frames of reference because there is only 1 moment when this occurs. At this moment for someone at N of ship1 to see T of ship2 they have to look in 2 different directions simultaneously. This is impossible. N of ship1 is simultaneously both passed and not passed T of ship2. This is impossible.
So this is why I'll be going to school on 4 hours of sleep.
I am attending online classes for 8hrs a day
At 1:18, how do we calculate the length of the metre stick calculated by the stationary observer? Do we say when t=0, x^1= 1, and then plug this into the Lorentz transformation? This gives you the expected result, but I'm just really confused...
Thank you very much for the videos, I really love it!
I am a high school student who tries to learn some advanced physics on his own. Such a helpful video.
Great Lectures, thanks Prof. Susskind
.....SUS
Okay professor
The point is that any line at this angle can be written as y=-x + c (for some constant c) ... and yes that c intercept is the constant since rearranging gives y+x=c along that line.
Really nice, although it has to be watched in speed 1.25 or 1.5 x)
+Johncowk thanks man....
Glad it was helpfull :)
Advice taken :D
A bit comical at 1.5x :D
LOL