Your Daily Equation #26: Einstein's General Theory of Relativity: The Essential Idea

Episode 26 #YourDailyEquation: Albert Einstein's General Theory of Relativity, phrased in terms of warps and curves in space and time, provides our most refined description of the gravitational force. Join Brian Greene for a visual exploration of Einstein's most profound discovery and the equations he triumphantly announced in 1915.
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.
The World Science Festival (WSF) is an innovative multi-media organization that produces original live and digital content straddling the arenas of science, technology, the arts, media, performance and education. With the goal of radically transforming public perceptions of science, WSF creates world-class programming, both live on stage and televised, featuring inspired collaborations, outstanding talent and novel production techniques that bring scientific discovery, insight and perspective to a broad general audience.
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[@MakatiMazz]

I’m a retired physics teacher. I used to use many of Brian’s examples from “The Elegant Universe” and “Fabric of the Cosmos” to explain Special and General Relativity. Thanks Brian!

[@carlton4610]

Thank you Mr Brian Greene, this lecture means the world to me. I'm an undergrad physics student and an older one now, and still an incomplete one. But I did get a solid foundation...from a certain few inspiring excellent professors... However several years ago having long talks with an astute physicist friend of mine about physics got me started again. I didn't get to a Relativity class in my first go round ,-- set of courses completed .. I believe I can learn on my own because if the great quality of lessons online....yours is one such source for me.. Didn't Ralph Townes learn a lot of physics on his own ,( with some guidance from a professor at Columbia?)..before going on to invent the MASER?? ID rather learn physics than anything in the world, had a bit of a *rough start but I believe I can do this so thanks so very much !

[@tgylfason]

These talks are phenomenally lucid. I wish the Great Courses company would take notice and offer to provide a further platform for Prof. Greene´s brilliant exposition of broad swaths of modern physics. Perhaps they already have.

[@geoden]

I must thank you Brian. I have known of your work for many years but only recently come across Your Daily Equation. It has forced me to re-engage my recently 78 year old brain and it delights me! I will follow YDE from now on.

[@faresalhawaj8288]

Thank you KZbin for recommending this channel. Informative, direct, and excellent explanation.

[@Dr10Jeeps]

Thank you once again. I look forward to these daily equation sessions.

[@alexanderkrizel6187]

This is so awesome. Thank you for doing these videos. I have been meaning to ask for GR for a while. But I actually had a special request about it. Not just the equation, but also the QM equation and where the two don't relate (if that even makes sense). Thank you again for this.

[@Roman-xm6ko]

Thank you for explaining the great ideas so clearly and fluently. I fall in love with science from your performances.

[@gedlangosz1127]

A beautifully clear introduction to GR. Thank you ever so much Prof Greene. May these talks continue for a long time to come, I'm learning so much.

[@juliozayd7514]

Sorry to be offtopic but does someone know a tool to log back into an instagram account? I stupidly forgot the password. I appreciate any assistance you can offer me.

[@mitchellbennett3638]

@Julio Zayd Instablaster :)

[@juliozayd7514]

@Mitchell Bennett I really appreciate your reply. I got to the site on google and im in the hacking process atm. I see it takes quite some time so I will reply here later with my results.

[@juliozayd7514]

@Mitchell Bennett it worked and I finally got access to my account again. I'm so happy! Thanks so much you saved my ass :D

[@mitchellbennett3638]

@Julio Zayd Happy to help xD

[@MillzTheAthlete]

I thought I ran out of time today, then I remembered it's all relative. It's always on time.

[@localtitans4166]

Brother u ran out of time in someone others relativity on ur relativeness

[@k7iq]

Hey ! Please remove yourself from my reality ! :)

[@nuzlock4481]

@@k7iq I got your reference buddy lol

[@NovaWarrior77]

Anyone who is type B be like.

[@Learner..]

😄

[@paulc96]

Hi Prof. Greene, Greetings from West Wales. Hope you are keeping well. Thanks for another great episode of Your Daily Equation. Looking forward to more GR. Best wishes & Stay Safe. Paul C.

[@periclesmelo1499]

Could you give a lesson about tensors?

[@deepakande1081]

please lesson on tensors

[@stevenutter3614]

What kind of tenders though? Chicken? Rib meat or breast meat? And afterwards maybe he should do a lesson on ligaments as well. 😁

[@u.v.s.5583]

@@stevenutter3614 A maths and physical therapy joint joke: How do you call an expired tensor? An extensor!

[@dcfromthev]

Who is he Rodney Mullen? : )

[@devnianjanasenarathn]

Beautiful explanations and teaching techniques. May you be blessed with an ocean of knowledge!

[@haimkohan9241]

Thank you Brian it was beautiful!! I am glad I discovered this site!!

[@io4439]

@16:01 Thankyou! Seeing this space-warp example settled a question that has been with me for some time.

[@spacetime484]

I do not understand how the scale shrinks or why we need more scales can anyone explain me if you understand

[@PanayiotisHalouvas]

@@spacetime484 have exactly the same question

[@cesarmoya7]

Thank you professor Brian!

[@sorenwintherlundbys]

Thanks a lot for this wonderful explanation. It is such a joy to listen in to Brian Green. And it is all for free.:-)

[@mishaangelo926]

This is the first time I have seen address to the obvious shortcomings of the rubber sheet analogy.

[@ucurie]

Yes indeed Misha. That has bothered me for so long. Finally a top level scientist presents it, but at the same time points out its inadequacy. I feel better that someone says that although it may be one of the best analogies, it defines gravity by using gravity and therefore doesn't really "explain" the concept.

[@frede1905]

@@ucurie A better way to visualize the concept of curved spacetime using the "trampoline" analogy is to imagine trying to lay down a long, thin and straight ribbon on the fabric. Now, because the trampoline is stretched and curved, this ribbon will appear to bend around the object. Since the ribbon represents the path of a particle, this gives the illusion that a force has bent its path. This is a better way to think about it, because this captures the main idea of general relativity, which is that particles follow straight paths, more precisely called "geodesics", and they will bend due to the curvature, again giving the illusion of a gravitational force. The obvious problem with the analogy that it only shows curved 2-D space and not curved 4-D SPACETIME. I haven't finished watching this video, so I am sorry if Brian mentions this in the video.

[@michaelsommers2356]

All analogies are imperfect. If they were perfect, they wouldn't be analogies, they'd be the real thing. One should never take any analogy too far.

[@Bungifun]

Agree, I've seen it explained many times but they never reference that this is actually in 3D. It may seem obvious but I can understand it confuses people.

[@sjlegends]

I'm Blessed, to listen straight from Greene 🖖🙏♥️

[@gaithouri]

thank you ... you are so charismatic ... its so great gift to teach us for free for those great ideas ... thank you

[@PLazzar]

Outstanding! Thank you.

[@daringumucio2779]

This is a fabulous video! I cannot wait until the unpacking of the GR equation!!! Thank you.🙏

[@viewer3091]

Thanks Brian. You are doing Great work.

[@adr5518]

Truly amazing ! Thank you so much .

[@jw2529]

Loved it! Very explanatory and theoretical xx

[@eggsandwine]

Thank you professor Greene for an excellent explanation.

[@paulmartha4999]

thank you so much for such a helpful information.

[@geethfernando3424]

This video is great. All the knowledge has been shared in a single video...

[@danielbachour9987]

Awesome professor Brian! .. had never heard about the example with the circular motion! Great! ... This series "Your daily equation" is the best thing that has happened to us, learning physics from one giant of our generation!! Thanks a lot professor!!

[@volvotango8363]

THANK YOU PROFESSOR GREENE!

[@jeffwells1255]

Very nicely done - as usual!

[@Dan-zq5wt]

Professor Greene explains things so clearly. Just brilliant!

[@makotonaakama5757]

Thank you so much. You are the best talker to give me an understanding about the general theory of relativity. Your talk makes me have an interest in physics. I wish i could have a good teacher like you about 50 years ago. I really enjoyed the happiness of getting a knowledge. Thank you again.

[@Llucius1]

I am so thankful that there is a video like this available , now I understand more on the reasoning behind Einstein's thoughts.

[@kostasfykouras2244]

These series are amazing!!! Please consider making it a weekly thing after the lockdown ends.

[@Martvandelay]

These videos are amazing!

[@gautomdeka581]

I was really waiting for this topic

[@NyteRazor]

Waiting patiently for a course in Einstein's Theory of General Relativity in World Science U.

[@adilsonsf]

Thank you for teaching us the basic. Although, you are very advanced. You have the patience to explain us the basis of these phenomena. Please go on. Thank you so much.

[@RC-uo3ds]

Thanks to Brian Greene for this video 👍👍🙏🙏❤❤

[@Walter-uy4or]

I look forward to hearing more about the time piece which I had failed to fully appreciate.

[@davidalves2561]

Thank you Professor.

[@tomgurskey8599]

Hey Brian I just became aware of these ‘daily equations’ which are most informative and well explained, especially for a somewhat dull tool in the shed like me. I watched this episode first then went back to E=mc^2. I’m glad that at some point you figured out the split screen thingy 😄

[@richardschultze9926]

Dr. Greene. May we learn about infinity and infinities? Thanks for your commitment to the series.

[@shiningstar8998]

What a great explanation!

[@simonapalosan3208]

Really gives a feeling about the GTR, I cannot wait for the derivation and the tensor math. Thank you.

[@anasghaffar7837]

Is there a derivation video coming?

[@spacetime484]

I do not understand how the scale shrinks or why we need more scales can anyone explain me if you understand

[@haimkohan9241]

Thank you from Israel. I am a yoga teacher, don't know much science yet read some science books here and there. This video helped me understand some general relativity. Thank you.

[@RaffaeleCanepa]

I love the new location! In this period it feels good to look out of some different window...

[@cecileconoly4140]

Thank you, Mr.Greene

[@niemerow1953]

So good! Thank you.

[@RajdeepDhareed]

Eagerly waiting to learn Differential Geometry in upcoming episodes to understand the Einstein Field Equation.....Thank you so much Professor.

[@spacetime484]

I do not understand how the scale shrinks or why we need more scales can anyone explain me if you understand

[@pengyu132]

Great video on General Relativity

[@sarmadnajim4839]

Wonderful lecture

[@localtitans4166]

Thank u sir .. u cleared my one of the greatest doubts

[@michaelwhalan9783]

Now we need to explain "Dark Matter" and "Dark Energy" in relation to General Relativity.

[@barryomahony4983]

"Dark energy" is just Lamda, the cosmological constant that Brian left out of his display of the Einstein GR equation. The real puzzle is why Lamda has the particular value that it happens to have. It's not zero, which was the assumption before "dark energy" was observed. But we don't know why it has the value it does, anymore than we know why the electron or the up quark have the masses that they have.

[@espaciohexadimencionalsern3668]

@@barryomahony4983 was dark matter observed?

[@frankcastellana1846]

We are free falling into a black hole ... Nothing to worry about cause we will never hit it. However we are stationary observers but to an outside observer higher up the gravity well our metric is changing; time is slowing and distance is contracting. If the distance standard that we have is contracting then all the other ones outside our reference frame must be expanding. The expansion is cumulative with distance from us therefore, no need for dark energy. Now dark matter. I think by now it is settled science that super massive black holes exist at the core of every galaxy. So when we observe a galaxy we are looking at a range of escape velocities, approaching the speed of light at the center. So when we look at a galaxy and measure the speed of individual stars, we must take into account the escape velocity of the region the star is in and treat the motion of the star as if the stars measured motion is added to the escape velocity of its position in the galaxy relativistically. This will have the effect of making stars toward the interior of the galactic disk to be measured as slower than stars farther out on the disk.

[@ViratKohli-jj3wj]

@@frankcastellana1846 incorrect

[@mohammadal-turkistany2151]

Thanks, I enjoyed it a lot.

[@charlesgantz5865]

Now you've covered Einstein's equations for the photoelectric effect, and the special and general relativities. I'd like to see the equations that started it all, first where he calculated Avogadro's number, and then where he calculated the equations of Brownian motion and proved the existence of atoms/molecules.

[@subhanusaxena7199]

Thank you please keep going on deconstructing the field equations and how Schwarzshild derived his exact solution. Do you find the light beam through an accelerating elevator helpful in explaining curvature of spacetime?

[@shorelinedirt5236]

I enjoyed watching this post very much.

[@Archaeometal]

Thank you, Prof. Greene. Outstanding how you can take these concepts and explain them so clearly and make them entertaining. Question: Is the same gravitational mechanism that causes Earth to orbit the sun apply to an object/person on the Earth (feeling the force of gravity)?

[@neonblack211]

Archaeometal yes

[@spacetime484]

I do not understand how the scale shrinks or why we need more scales can anyone explain me if you understand

[@casiopea1953]

Breathtaking Class of the Einstein's General Relativity creativity of a Stunning Scientist/Physicist 🙏 I'm not a Scientist, just I love learning, from a Simple Human Being 🙏 Thank you for all you do!

[@joshuamark1601]

For connecting acceleration and curvature, I always thought of it as visualising a displacement-time graph (or maybe a space-time diagram) A motion of uniform velocity would be a straight line; an accelerated motion would be a curved line.

[@MyWissam]

Thank you

[@vincentv.9729]

Finally someone who explains clearly a question noone answered me when I ask: if gravity is acceleration, why are we not now speeding at exponential times the speed of light? Because acceleration is also a change in curvature, not only a change of speed! Thank you professor Greene, these daily equations are just fantastic.

[@Okkurg]

Any concept you explain comes clear as water, what a gift. 21:55 tho hahahaha

[@rgudduu]

Good teaching style. Beginner level coverage

[@alimojebi9650]

Thank you, professor Greene! It's an art to simplify such complex concepts into courses like this. I really enjoyed it. 👏🙏

[@sagarbhattarai8161]

He is always, so full of optimism

[@claudioalancarcano9758]

Brain is just so clear...! Thanks!

[@annagorska1229]

The 3-D animation of a space deformation by a massive object is great! ...😍 I've always wanted to see that in 3-D. Thank you! 💖

[@Abishkarplayz-cheese-pg7ku]

Hi, it would be helpful if you put everything in a playlist covering all of a certain topic such as general relativity.

[@johnhamilton7762]

Thebottle of water with the hole in it the dropped was a great example of the equivalence principle you used.

[@seekingtruthfacts7743]

Just saw World Science Festival 1995 talking about general Theory of Relativity.

[@HM-cw8im]

Wasn't WSF founded in 2010?

[@topquark6919]

From the legend, himself. Awesome stuff.

[@strikeblade6669]

love you professor, i wish i can meet up with you someday

[@ahmadmumtaz4947]

Sir : I am at loss to find words to thank you and pay my gratitude :as siting so far away: I learnt a lot from you: as Einstein’s Special Theory of Relativity and General Theory of Relativity: oooh wow:without your help it’s pretty hard almost impossible to understand:I follow your Stage lectures as well: Your way if explanation presentation communication to make understand guys like me: and of course a lot / millions like me across the globe: that’s why I repeat that I don’t have words can’t find them at loss: how to thank you and to express my gratitude: that’s the beauty of science Legends like you only have the sensitivity to pass on your knowledge for nothing no self interest whatsoever : deserved our full appreciation: Keep up the good work beyond boundaries..!!🙏🙏

[@spacetime484]

I do not understand how the scale shrinks or why we need more scales can anyone explain me if you understand

[@ajays8355]

Please do a video on Electrodynamics

[@beckywaytoomuch]

Love the intro 💕

[@somnathsaha7391]

Great 🙏thanks sir 🙂☀️

[@smotpoker81]

21:59 "or if you put yourself in the shoes of the bottle of water, whatever that means." i don't know why, but that made me laugh hysterically.

[@andreranulfo-dev8607]

12:22 Just brilliant. General Relativity was the most powerful mind exercise ever.

[@David-vl4xm]

Great view, reminds of Scotland

[@darrellgarrison4]

At the expense of great mathematical complexity, GR has pushed the "what's the mechanism" question one step further down the road. It enables calculation of the curvature of space-time by mass-energy and the motion of things in that curved space-time (and many other wonderful results), but it provides no physical mechanism by which the curvature of space-time is produced. The problem appears to be that we do not yet really understand the structure and composition of space-time. Is space-time discretized at the Planck scale? Does it consist of a grid of nodal points connected by elastic "strings" of Planck Length? Are there short range forces that would bind nodes (or string ends) if they were brought in proximity by local folding and/or rotation of the Planck grid? Does mass-energy warp the geometry of space-time because mass-energy IS distorted space-time? Whatever the answers to these questions may be, we would still have to explain the mechanism by which those forces are produced. The rabbit hole of physics appears infinitely deep.

[@TimothyMusson]

Thanks for the great, clear explanation! The animation at 16:00 is how I'd been picturing "gravity" in my head (...and yes, with just a single object - more than one gets hard for me to imagine). It'd be really interesting to see something similar with two or three objects influencing each other (orbiting, passing by) in a "3D grid" rather than just a single object all by itself. Does anyone have a link to animations like that? :)

[@spacetime484]

I do not understand how the scale shrinks or why we need more scales can anyone explain me if you understand

[@seanmortazyt]

fantastic!

[@physicspoint3356]

May God bless you sir

[@dzaharsher6078]

I love the 3d depiction because thats how ive always pictured it. Whats nice about that is you can see a 2D plain of space time being bent in all directions. Above, below, beside, behind and in front of the object, and how when the object is further away the fabric bends less. So instead of Newtons' theory having instant influence from one object to another the object would instead have a instant influence on space time. Pretty cool

[@ritemolawbks8012]

The 3d depictions are actually using Newton's gravity law propagating at a finite speed.

[@martintopinka8295]

Is the approach of sticking together different LISes an equivalent reasoning for linking curvature with gravity to the tornado ride you mentioned, or is it conceptually little bit different?

[@hinamiemad6981]

ありがとう! Thank you

[@jonathanbyrdmusic]

Can anyone explain why it takes more rulers to measure the inside? I don't understand that.

[@daveotx]

Beautiful

[@stevenutter3614]

29:58 Right but the connection isn't of the same nature of that of the equivalency principal , where there's no test you can perform to tell you otherwise, (assuming you're not allowed to look out the windows of the space craft) how can being on the inside of a spinning ellipse or circle be acceleration , if you were in deep space and stopped the engine spinning the room, it would continue to spin forever assuming zero friction with the particles outside or the atmosphere inside keeping you alive right? When I think of acceleration and gravity y I think of the need to constantly add more energy to the system, you not just moving fast, your moving fast quicker than you were the previous second , Also is there a name for increasing acceleration. Like increasing speed is called acceleration what about increasing acceleration. Like perhaps a second ago your speed was increasing by 9 meters per second, evey second, but now it's increasing at 10 meters per second, per second. Accelerating acceleration. Can't you just follow that down an endless rabbit hole. Turtles all the way down type of thing ? I don't really know what I'm saying. What about the Earth is the Earth accelerating through the galactic medium or is it at a static velocity that is slowly decreasing, or does it go through periods of be acceleration due to gravitational interactions, and deceleration to the other gravitational interactions and friction within the galactic medium. ?

[@gpcrawford8353]

In the UK 🇬🇧 we call the tornado ride the rotor and Einstein uses this analogy in one of his books for a non mathematical reader like me. In other words on the rotor you are stuck or pushed against the wall as though gravity pulls you to it. When it stops gravity is restored to pulling you down in other words there is equivalence between the two.

[@33blackbull]

Iv got a very long question and was really hoping you can help. We always mention these amazing minds throughout history like Newton Maxwell Einstein etc that where leaps and bounds ahead of everyone and push our knowledge further. My question has a few questions in it. Like, when do you think the next big mind will push use forward again? Do you think they already exist but will only find out in the future?maybe we won't see another mind jump us forward again as maybe there are no new big physics questions left? or we have to wait for technology to catch up to prove these theory's correct? Or maybe we now have lots of these magnificent brains in our current mix and it's hard for someone to stand out? Do you think maybe the next Einstein will be in a diffrent filled like technology that pushed are knowledge further? I would love you to do a piece on this and have your thoughts. Thank you

[@ThurVal]

One quetion please! Since acceleration is relative.. is a free falling electron radiating or not? Thanks!

[@ashwinrajan1341]

Same doubt here.

[@GaborRevesz_kittenhuffer]

hey that looks just like the place in danby where the plateks used to live back in the 90s!

[@unbeatablehero]

amazing

[@Bungifun]

Great video but I missed the point on why the circumference of the circle is suddenly bigger due to motion. Doesn't that risk space to become infinitely compressed as you approach the center of a black hole? And because it is spacetime, I guess time is getting compressed as well so from an outside observer it looks like you are hardly moving but yet you do experience time and space at an accelerated pace (speed of light) yet constant so time has to show down? So it takes kind of forever to reach the center of a black hole? And I guess the reverse is true? If you measure in the opposite direction of the motion, the rules are stretched so the circumference is smaller. But my understanding here is that this would only be if you leave the time aspect out of it. So within space time wouldn't such an accelerated also cause a shrinkage of the measuring itself?

[@pratikpawar7425]

Love to see him on discovery channel

[@mskEduTech]

Its good you started GR. Just wanted to know how to solve GR equations.

[@mskEduTech]

@@wifixmash3r ???

[@enkaramessi10]

Sir please explain the math of weigner 6j matrix of LQG