Your Daily Equation #3: Lorentz Contraction
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- čas přidán 20. 05. 2024
- Episode 03 #YourDailyEquation: Last week, Brian Greene spoke about time dilation and the impact of motion on the passage of time. Today, as the counterpart to time dilation, Brian Greene will unpack length contraction or what is also known as the Lorentz contraction. If you want to hear more about the "weirdness of space" you'll want to tune in to this episode!
If you have a favorite equation that you'd like Brian to discuss next time, be sure to let us know in the comments.
Even if your math is a bit rusty, join Brian Greene for brief and breezy discussions of pivotal equations and exciting stories of nature and numbers that will allow you to see the universe in a new way.
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Listening to you for the last ten yrs or so has actually made me SMARTER !! Wish I had half your education
Many thanks. I enjoy making these videos and the other programs, so am happy to hear you've enjoyed watching them.
yeah that other half of his education is trash
@@briangreene407 I can honestly say that this is the best way to learn. The teachers in my country don't use these animations and are not very clear in their explanations. But, you sir, hats off! The quality of your lessons is outstanding, and you spend less time teaching us.
And yeah, you both share a same first name. Brian Y and Brian Greene.
Seeing you on screen is itself an inspiration to study physics, waiting for you to do Einstein's Field Equation..love from India
Dear Mr. Greene. A deep and sincere thank you for all the stimulating knowledge that you have made available through your books and work. I stepped on a theory named Rotating Lepton Model. Since it's promise is stunning, I was wondering whether it is something that you think is worth looking into further.
I m going to tell my teacher i hv started online classes with prof Bian Green 😅
Absolutely...but no grades in this class. Just ideas.
And that's all I need no degree no grades only ideas and knowledge.
Corona effect
From Morocco here, the knowledge you share is echoing all over the world. Thanks a million Dr Geene
Mehdi you give me hope. stay open minded and be skeptic my brother. A brother from Eritrea.
These are just great. It’s been nearly four decades since I graduated in physics and astrophysics so it’s nice to get the rust gently brushed off by these lucid videos. I only wish we had professors as good at explaining stuff as you back when I was at uni.
Anyone else notice he does these all in one take? Impressive
One of the beautiful description of scientific phenomenon.
This is a very very interesting series! Thanks a lot!
Thank you! Always enjoyed watching/listening to you. This is really welcomed content especially now that we're all locked down! Thank you for sharing your knowledge and time!
Thank you so much for taking the time do this for us all. It's a highlight of my lockdown day.
I remember reading your book while working at a warehouse somewhere in NJ. I love the fact that now I can see you doing the math. Thank you!
Well explained my friend! When I have more questions than answers at the end, you've done a great job.
Thank you very much for this excellent series and you have the power for transmitting knowledge to others.
I LOVE THESE VIDEOS... so glad i found WSF! Cant wait to attend!
Thanks again for the great explanation and wonderful simulations from both outside, and inside out, can't wait for tomorrow!
Wonderful. Thanks for the effort, professor Greene. I watch these episodes when I wake up every day.
Thanks for the cool content, look forward to this every day.
Oh wow! Thank you Dr.Greene. FINALLY Physicist doing math and showing equations publicly. This is a change in the Culture we need badly. I'll be watching every one of these videos. BRAVO!!! Please more of these! Please!
(Request for how Magnetic Field emerge from Special Relativity. Also some lessons on Waves in future videos please.)
My right ear felt left out :(
excellent, right channel no sound and my left speaker died :/
Mono recording.
Windows: Settings > Ease of Access > Audio > Turn on mono audio
Let him know please
@@boom10611 on app on Android phones?
Could we please do some Supersymmetry equations? (or explaination of the theory)?
yes please this. i struggle hard
Love the series!!
Thank you professor Brian!! It would be interesting to see an animation of the perspective from inside the cab of the outside world when going at different percentages of the speed of light. For instance what would the outside look like at 50% the speed of light? Then what would it look like at 75%? Then at 80%? 90%? Etc, It would be amazing to see something like that! Thanks for being an awesome person!
Hello Prof. Brian ,I love your lectures....Thank you very much Sir.
well. sir maxwell-hertz equations would be nice on next episode
Really enjoy this series! Good refreshers from the WSF courses so far. A great reason to take a break from my day job each afternoon to catch up on equations and Einstein himself would be proud! Thanks for everything you and the WSF team do. Look forward to the wave equation and Heisenberg’s Uncertainty Principle getting called out of the bullpen at some point.
First off, these are quite amazing, thank you for taking the time to do this, it is certainly a great way to supplement and enrich our physics endeavors. Is it in the cards to have a series involving the Klein Gordon equation leading up to and developing the Dirac Equation? That is fairly involved and it would be amazing to see you go through this, Thanks!
Thank you Dr. Brian
Great series. Really enjoy watching this. I grew up in Germany and the Germans have a much more abstract approach to physics and mathematics. This is so refreshing!
Thank you professor.
Thankyou Brian, you make it more than just numbers and math. You are making a massive difference. I wish I could have have attended your recent talks in England.Train tickets in our country would have cost me £149.00. I have ordered the book instead.Looking forward to reading it. Once again thanks from the U.K Anthony.
I'm an engineering student . I learned a few things , listening to this lecture .
Thank you very much , Professor Greene
I like how you do the equation then a visual example. I think that's a very powerful way of teaching. I've watched some physics lectures just do equations, and for the life of me I can't understand it. I'm dyslexic, could be the reason why. I see numbers and words back to front.
Thank you thank you and thank you. You are a great communicator. I enjoyed so much the world science festival and your maths explanations are so comprehensive i will definitely get my physics degree... if it wasnt late for hubble is not too late for me. All my best wishes and thank you again for being such an altruist for spending your time trying to make the world enjoy the reality of the world.
this guy is simply a genious the synthesis power that he has, in just 2 words he tells u exactly what u need to hear
Why on earth would someone dislike this? Guess they didn't understand it, somehow.
Ludwig... Logically, For All YT videos, there exists at least one dislike for each video.
I'm sure someone could put that in standard logical notation, which i will leave as an exercise for the reader.
I love these videos and your books! Two interesting things for discussion could be 1) using gravitational waves to propel objects through space at close to speed of light (if that is possible, how much energy would be required and what the experience would be like in the craft) and 2) what it would be like if you were experiencing the universe as a photon of light. From what you said about time dilation and space contraction at c, it seems like your time would completely stop and space would contract to the size of an Infinitesimally thin disc so would time and space stop existing at all for you as a photon? Would there be no difference in the photon's experience whether it traveled 1 mm or 30 billion light years?
Great session again. And please add Schrödinger's equation to the list. 🙌
Love these. Very enjoyable. I am learning.
Great one thank you Brian.
Thank you Professor, i would like to ask a question: if we try to imagine the moving Clock at speed of light is at rest relative to the stationary clock, and in the fixed direction ; the stationary clock slow experiences time differently and slower! ?
I am look forward to get my answer sir.
I would like to suggest in further episodes, please explain the lemaitre math and start of Big bang.
Thanks
I loved the class.Its been wonderful to read your books and attend this class daily.Ive learnt so much from you.i hope we touch general relativity and Einstein field equations.
Thank you for such a clear explanation. If you don't mind me asking a question...
Does the value of PI change in circular relativistic motion or/and does general relativity complicate matters because of the acceleration toward the center?
I was thinking about the particles in the LHC traveling near the speed of light in a CIRCLE. In the direction of travel the particles "experience" a shorter distance around the collider circumference. In the perpendicular direction there is no contraction but there is acceleration. Thanks gain.
Keep going Brian. 👍🏻👍🏻
Thank you very much sir, I was always curious about theory of relativity but now I will got more clear about it because of you,
Love and respect from India🙏
Excellent.
Goosebumps..🤯🤯
Thank you for the good quality of this series, I enjoy every second of it ! I just have one question : why did we assume that L_you = V * DeltaT_you (you = the guy on the train I guess) ?
Cant wait wont wait
BRAVO!
Awesome material 👍👍😁
Another great video! Thank you for the clear explanation. Would be helpful to the lay person like me to see a real-world application with actual numbers at the end of the explanation so we can perform the calculation ourselves and check the answer. For example, what would the Lorentz contraction be from my perspective for a taxi passing by at 80 mph? I know the number is ridiculously small but I’d still like to know what it is and check my math. Or perhaps add just a brief qualitative discussion of how physicists apply this equation to investigate real-world cosmological issues..thanks!
Brain Green sir, i would like to hear from you a little bit about my favourite four equations that are situated in the heart of physics..
1. Hamiltonian equation for classical mechanics
2. Maxwell's equations for electromagnetism
3. Schroedinger equation for quantum mechanics
4. Einstein's feild equations
thank you sir...love from India❤️❤️
He has done most of those. Check past episodes. Good to have you here!
Thanks for the explanation. I was a little confused about where "you" and "me" were, but I think I got it sorted.
?An analogy I thought of. It sounded like you were describing proportional dividers, where one side is moving, and the other side is not moving. Eg, ratio of 10:2, the 10 would be distorted as it moved past 2 that's not moving. I can see why the light (information)from 10, is distorted as it passed into 2 (my perspective). Because the light (information) is doing two things at once. So light is constant, and it's doing two things at once, you get a distortion, as I perceive it. Have to think about it more. I do a bit art and use proportional dividers. Thanks. Looking forward to your next lecture.?
Plz Explain Ramanujan's formula that helped to Understand Black hole or Maxwell's Equations
Please do comparison of an EM wave equation where the strength of E and B are such that the energy in one wavelength cubed - say 500nm cubed is equal to hf where f=c/wavelength. And then compare that equation to Schrodingers equation for 1 photon with energy hf. (Using the same f)
It never occurred to me to use the watch to measure length until I watched this episode. Thank you, Prof Greene.
I have a question tho... From what you said about perspective.... could it be the perceived contraction is just optical and not a material effect... Because if it is a material effect? The Car driver and the people in the environment should see the building bend also
Sir, you're really helping me become better at maths and physics together! Can't wait to meet you one day...Also, listening to make me believe that science isn't uninteresting but your teacher is bad... Thanks for making it interesting.
i love you man. thanks
Thank you for the daily equation!! I am wondering about the Lense-Therring effect.
A question related this
I’m an idiot when it comes to Maths Brian, so please forgive me.
Would a photon trying to and perhaps *just* escaping from a little outside a black hole have its wavelength compressed to such a level as to become undetectably small, and or would its slow speed have an effect on this that would make it visible to an outside, ‘static’ observer?
My question is how could you measure the train if it was comming towards you or away from you?Also if something moved over the speed of light would it go backwards in time like the train moving would you see an even at the back of the train happened before the front?
It is not clear to me toward which point the train is contracted? Whether it is contracted toward back of the train or front of the train or maybe toward the
center of mass of the train all from the perspective of stationary observer?
Does space with a train is contracted or train is contracted within space, from the perspective of stationary observer?
Watched your video twice to finally understand it. This is some whacky stuff. Perspectives are very important to understand.
We are living in a whacky weard world and we don't even realize it
Another great video, amazing how you can show something so deep abou reality in such a didatic manner.
Seeing this video I remembered about the "Motion Groups", the Poincaré Groups and the Galileo Group, and how they encode other kinds of "relativity" and of "motion". I believe that would be a good topic to talk about.
Suggestion: Euler’s Equations and Gyroscope Equations
I don't think I properly understood E=MC2 Until I watched this video. I've hit my head off it and had it been explained before but all that left me partially understanding it. And it's not like I've memorized the proof of this so I "understand" it in the way a technical physicist understands it... But now I feel like I properly understand the relational importance of mass and speed and how that defines energy in a way I wouldn't have been able to contemplate before. I also see how that might imply relativity but I still don't arrive in my head at all the physics I've been exposed to. Still, my ignorance is being chipped away bit by bit.
Prof Brian I loved your special relativity course on World Science U. I hope you will get a chance to teach us general relativity and QM soon.
Suppose the train station has the same length as the train station when the train is not moving.
Then the experiment is symmetrical with respect to the length measured.
Then, knowing that, with the train moving with a fixed speed "v", if I were on the train, I could start the clock when entering the train station and stop it when passing the end.
Then, would I see the train station shrinking by the same factor "Gamma" as the observer on the station would see the train shrinking?
Brian,thanks a lot for these videos!Perhaps you can help me with this question:Of course special relativity has been confirmed by several experiments.Could these same experiments be explained by Lorentz theory of light, if only we choose to believe in a more complicated theory?
Brian can you please please do some quantum mechanics. I think a good transition from the relativity equations would be the foundational QM equations. Maybe start with Uncertainty 🤓...love the series!!
Thanks for sharing your brilliant knowledge, Brian, sorry for this dumb question, if the motion is perpendicular to the observer, how diverse would the equation perceive, Cheers.
Sir pls explain on how to observe from the trains perspective and not getting back he reverse answer exactly what u said in the video the 2 clocks one at front and one at end.. how to solve that part??
That is a bit more involved -- but if you want more details, head over to World Science U and watch my full (free) course on special relativity.
Is length contractions happen in acceleration frame also ?
Prof Green, firstly, thank you SO MUCH for these videos, i cannot get enough. I have lapped up the wonderful explanations of your first videos and cannot wait to get to the next but I have a question regarding this one and no amount of googling seems to enlighten the answer... As a stationary observer, let's say i have a tape measure and i were to 'sling' the front of my tape measure on to the front of the train as it passed me, and then read the length as the rear of the train passed, surely i would read the same result as the passenger? If that's the case, given physics is nothing without its reflection of reality - or theorised reality at least - is this not an extrapolation of the spacetime contraction and dilation theory taken too far?
I don't know how the professor would reply but, since he hasn't given one, I will volunteer an answer.
Certainly, you would measure the same length as the passenger on the train, but there's a good reason for this that unravels what seems to be this contradiction (that you get different answers depending upon the method you use to measure the train).
From the moment you throw the front of your tape measure and it catches onto the front of the train, the front of the tape measure is traveling at the same speed as the train. Then, as the tape unwinds from the reel that you are presumably still holding in your hand, every part of the tape which has come unwound and is stretched along the side of the train, is also travelling at the same speed as the train.
This means that the unwound portion of the tape measure will suffer the same length contraction as the train.
Obviously, then, if the standard length (the tape measure) you are using to measure the train is shrunken in the same proportion as the train itself, it will appear that the train is indeed the same length as measured by the passenger who is stationary with respect to the train.
Just watch out for your hand and make sure you let go of the tape measure reel before the train rips it out of your hand. That train is going really fast!
I wonder if you lived in a gamar close to the speed of light, would it change the way you think (would it effect the mind)?
I have a confusion. Can somebody please clarify this for me: As I understand, delta-tMe is the time elapsed on the stationary person's (call S) watch, from the perspective of the stationary person himself; delta-tYou is the time elapsed on the stationary person's watch, BUT from the perspective of the moving person (call M). Further down in the equations we encounter the entity V.delta-tYou which we called Lyou. Now the way I understand it, Lyou is the length that I (the mover) believes that you (the stationary person) must have measured. Now I have two questions: - 1) Why should this length Lyou be equal to the absolute "tape-measured-length" of the train (210 m, in this example)?
2) Since the fact that relativistic effects are at play is common knowledge to both the mover and the stationary guy, and given that I (the mover) know that you (the stationary person) is using speed X time methodology to calculate length from "your" perspective, why should I think that you will end up measuring Lyou (=V.delta-tYou). In other words, if in the formula for Lyou, I care for the speed that "you" see: V, why should I not care for the time that "you" measure: delta-tMe ? In other words, again, the formula for Lyou uses the speed component from S's perspective, but the time component from the mover's perspective. What am I getting wrong here ?
I really want someone to answer this, I’m wondering the same!
I
Sir you mention in your talks that theory of General relativity is kind of tough and complex . Will you present that complexity in simpler ways . I am talking about einstein field equation .
Love you sir love from india ❤️❤️😊😊
I'm enjoying this series of talks and have a question: The bystander's stop watch will indicate the train passing by in less than 7 seconds. What effect would the train's motion have the elapsed time of a passenger on the train? What a passenger's stopwatch indicate 7 seconds to pass the bystander? And, if so, from the perspective of the passenger, the passenger can claim that the train is 210 meters in the length while the bystander can claim that the train is less than 210 meters and both be correct.
It just does not make sense to me, I do not know why! Two options only: I am insane or something about the length contraction and time dilation is wrong! Anyway, I admire your personality and method of teaching Prof Greene.
I recently published two new theories (through a book), one is about Time (what is time itself), and the other one is about wave-particle duality (quantum mechanics). Check them out guys, the book is called “Me, You and the Next Generations.” It can be found on Amazon or kindle.
Great to see BG's passion for this stuff, clearly part of his DNA. Speaking of which, are there any equations in evo bio that can be focused on?
Hello Professor...I was hoping that u would solve the twin paradox. I looked at the internet but I couldnt understand. Hope u will clear the twin paradox in your next video. Thank you. 😊😊
Professor can you please explain "HOW MOVING CHARGES PRODUCE MAGNETIC FIELD". Because every one and every textbook says magnetic fields are generated perpendicular to moving charge but HOW and WHY
Does length contraction and Time dilation not occur simultaneously according to an observer?
If you are stationary and observe an airplane pass at speed comparable to c, by special relativity you will observe the plane to be contracted along its line of motion, also if from the back of the plane a light pulse is emitted directed at the front you, the observer, will find the time dilated. That is with respect to you, the light pulse takes longer time to reach the front.
But if the plane is contracted in the first place why would time seem to slow down with respect to the observer, considering the contraction would make the time for the pulse, according to the observer, to reach the front more quickly.
Does this imply that we can only measure time dilation or length contraction not at the same time?
Or the length of the pulse "shortens" as well according to the observer?
Please tell us about schrodinger eqn and wave function.
You say the stationary observer uses their stopwatch to determine length by measuring the time that elapses from when the front of the train goes by until the back goes by, multiplied by the train’s velocity. My question is, how would they know the velocity? Would there not have to be a second observer a known distance along the path of the train with a watch to record the time when the front of the train passes them and who would then compare their time to that recorded by the first observer to arrive at elapsed travel time? I raise this question because you say you reversed view points to avoid the need for two stopwatches on the train - one at the front and one at the end. It seems one needs two watches regardless of viewpoint.
This might be a stupid question, but does an object physically shrink or is it just the light that makes the effect?
Is there any issue with the v^2 having time (t) in its base equation? V=D/t
I hope someone will read this...
I have a little doubt in this derivation in time dilation we took stationary time ∆ts in left hand side and here we took ∆tyou on left hand side but here ∆tyou is not stationary so why we took ∆tyou on left side?
Does the velocity remain same for both inside the train and outside the train? Why dont we use Vyou and Vme terminology just as we used Tyou and Tme?
I'll take a stab at this. It's because velocity is already a measurement of distance over TIME. It would be redundant. This is precisely why time dilation comes into play as well.
I have a question that could provably be stupid but here it goes? The result of the equation would be different if the person in movement os going against the direction of the Earth rotation?
With this analogy, can we say that for a stationary observer, two things that occupy vastly different space but travelling (approaching) at the same speed, are perceived differently? For example given a train and a tennis ball both approaching me at the same speed, I will perceive the ball to be approaching faster?
I realy like these videos and i think they can be longer like 30 - 45 minutes or so. Like a small crash course.
Is the stationary observer more important in validating E-MC2 (for measurement's sake) than is the train passenger which senses no motion when it comes to an assumed Lorentz length contraction? Is length contraction an actual physical process or an optical illusion of light given different observational perspectives? How will the train passenger verify that they are indeed "length contracted"? On earth, we should be slightly length contracted in the common direction which we are traveling, given the fact we are indeed moving through space. However, we can't perceive our measurable length contraction because we are the passenger on the train. It would seem that length contraction is not a physical process since it cannot be measured by the passenger as evidenced by Michelson-Morley's experiment, correct?
How do you resolve twin paradox????
great!! light cones please..
Please explain Schrodinger equation