The biggest ideas in the Universe - with Sean Carroll

Join Sean M Carroll as he explores deep questions about the cosmos, laying out the framework of classical physics from Euclid and Galileo to Newton and Einstein. Watch the Q&A for this video here: • Q&A: The biggest ideas...
Sean's latest book 'The biggest ideas in the Universe 1: Space, time and motion' is available now: geni.us/V3Or
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Discover the ideas that revolutionised our view of nature and helped us gain a deeper insight into the workings of the Universe. In this talk, Sean discusses the laws of physics as you've never understood them before.
This livestream was recorded on 6 October 2022.
Sean Carroll is Homewood Professor of natural philosophy at Johns Hopkins University. He won the Royal Society Winton Prize for his book about the search for the elusive Higgs boson, 'The particle at the end of the universe', and 'The big picture' was an international bestseller. Sean lives in Baltimore.
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[@MichaelEhling]

I love that Sean Carroll took the time to explain the equations. He's right: we don't need to solve them, but we can handle them, understand them, and see their usefulness. Bravo!

[@hamidmazuji]

you don't need to solve them ? what ? the point of mathematics is either obtain numeric or analytic solutions. that's the whole point - their "usefulness". and i reserve the right to believe you when you claim to "understand" them

[@MichaelEhling]

@@hamidmazuji Yes, you are right. I should have been clearer. I should have said, "Among the audience are people like me who aren't professional physicists or mathematicians but who value this work. We appreciate seeing and understanding the equations even if we can't or don't want to do the 'working out' of them." And I 100% support the idea of reserving belief until proof.

[@hamidmazuji]

i apologize for being so blunt. at 47:15 he provides a great example of a solution for the energy momentum tensor for stars and planets. i would have liked to see other examples, such as a particle in an accelerator

[@hamidmazuji]

or a photon, or a gamma ray, or a gyroscope

[@hamidmazuji]

what does the energy momentum tensor of a millisecond pulsar look like

[@guywebber9312]

Sean is one of the most brilliant science communicators...We are so lucky to have him in our time period.

[@manicmadpanickedman2249]

I explained this with a simple prop without any complicated gobbledygook or idiom just revelation And relativation ... water.....hermetic ... enertia ie. gravity or GRAVITY flux.... ground effect ie .. boundary effect .. shear plain ...friction frictionless principle of least action ... water has atributes and modes !!!!!.... hence its suface tension makes water bead up ..... no mater what height that you drop water from it will return to as long as you do not introduce impedance.....ie .. flow stream... stream line .....😎 slick as a bic A dynamo dose not have an active resistance it is passive as in I must introduce energy by converting the mass of a standing colom of water next too an arc/parabola of the same height ... and have a pendulum for least time.. and as above so below pendulum dual aparatus as water is like a yo yo . ..ctrinity .BIG G little g .... tesseract . Torus .... figure 8 but1 ...top down and sideways . Maximum mode minimum not maximum minimum mode

[@manicmadpanickedman2249]

A freaking 5 year old could do Relativity... you all been hoodwinked ... hornswoggled ....bewitched...bamboozled gypped..... corn-fed ... ignorance is bliss 😊 who thought... you thunk ....about think...bet you can't hear tone deff .... sweet devotion Chandra ....soma mantra ...

[@Mizzkan]

@@manicmadpanickedman2249 it’s a pity your a 4 year old then.

[@manicmadpanickedman2249]

@@Mizzkan exactly in which way or is it because I don't care about the jargon just the idea ... to put ords too it does not do it any fairness

[@redneckshaman3099]

I'm addicted to pigger nussy 😻

[@peterwan9076]

This is the kind of lecture people have been expected from a professor who knows how to communicate the difficult concepts in physics. I have to praise Prof. Sean Carroll for NOT backing down to the publisher crooks who want to get rid of all equations (I am sure they would prefer to print money instead of books if they are allowed to do so). If you talk about science without equations, it is like talking about investment without money or literature without words. Mathematics is what nail down the concept so that at the end of the day you know what you have learned. For those who really understand the subject, it is a joy to be able to explain difficult equations using language that laymen could understand. Keep it up, Prof. Sean Carroll. If the audience could understand your video, they would have no problem in buying your book too. People are expecting more of the same kind to come in the future.

[@ashcross]

Sean is such an eminent and humane and eloquent teacher. He makes me feel fairly bright for an hour. It is an honour to bask in his knowledge.

[@Sileonex123]

I love listening to Sean Carroll speak and do every chance I can

[@alexanderabrashev1366]

I'm the same with Brian Greene

[@PetraKann]

I agree, As long as Sean sticks to Physics and the Philosophies related to this field and science in general

[@CorezMon]

Sean has his own channel on KZbin where he has uploaded many podcasts, lessons, QnAs and he interacts with his subscribers regularly!

[@htopherollem649]

@@CorezMon never even thought to look for my favorite scientists having KZbin pages! thanks for opening up my universe in terms of content!

[@ce5834]

I always listen to his mindscape podcast, especially the monthly AMA

[@biffy7]

This is crazy. I’ve been trying to understand the math behind this for over 40 years. This is the closest I’ve ever gotten. I’ll need to listen again, and again, and take notes. Dr. Carroll, I can’t thank you enough. Oh, and I ordered the hard cover.

[@alexiskaplan]

I sympathize with you

[@atticuswalker8970]

Try e=ymc² where y is the Lorentz effect.

[@shantanulokhande3730]

It's beautiful how Sean explains things in a simple fashion. This is art. Ever since I read his books, he has inspired me to learn more, know more, understand more in ways in which I never knew I can. He is one of the best science communicator out there, surpassed only by the great Carl Sagan. Sean I loved your explanation and will continue watching your videos, gaining insights, and continue to be inspired from your work. Thank you for such a brilliant session. Hoping to see more from you.

[@REDPUMPERNICKEL]

Simple, not simplistic. Simplistic is derogatory.

[@shantanulokhande3730]

@@REDPUMPERNICKEL Sorry about that. Made the edit. Thanks !!

[@REDPUMPERNICKEL]

@@shantanulokhande3730 You're welcome, no apology necessary, we all use words whose meanings we have extracted incorrectly from their contexts. A similar thing happens in regard to pronunciation. I remember reading 'Persephone' and in my head hearing it as per-seh-phone and being amused to hear it pronounced per-seh-phony, i.e. correctly. lol.

[@necktwiozfguah8818]

James Beacham is my favourite

[@citizen240]

@@REDPUMPERNICKEL Like when I was a kid one of my favorite cartoon characters was Yosemite Sam; to me, YOSS-might Sam.

[@vinodt1347]

I lost vision for about 3 weeks. I survived just listening to these lectures. Thank you Sean. You are a great communicator like feynman

[@Seekthetruth3000]

Did you get it back?

[@beeble2003]

@@Seekthetruth3000 Yes. "For about 3 weeks" implies that he lost his vision at some point, and regained it about 3 weeks later.

[@DudokX]

It's mind-blowing that black holes were already in the equation without anyone even Einstein knowing anything about them.

[@JiminiCrikkit]

I don't think anyone explains physics like Sean Carroll. I might not be an 'Everettian' but he sure makes sense to me when talking about these things

[@bluesque9687]

Sean Carroll is the best presenter Physics has!!! And all the great scientists would thank him for that-- make it simpler for the masses to understand!!

[@minivanjack]

Sean Carrol is by far the best communicator I have heard in high- level physics. The formulas in this are over most people's heads but do not hesitate to look at Carroll's other lectures, he always brings some good information for every level of viewer.

[@HarryNicNicholas]

sabine hossenfelder and janna levin are pretty good, and amusing too....

[@Tore_Lund]

@@HarryNicNicholas Sean Carrol is a firm believer in the Multiverse, Sabeine is not. Would like to see then in a panel discussion.

[@Neme112]

@@Tore_Lund Do you mean the many worlds interpretation of quantum mechanics? That is quite a different thing from the multiverse - either one of these or even both could potentially be real at the same time. I get the impression that he is agnostic on the multiverse - it might be true or it might not, but there's nothing suggesting that it must be, but on the other hand there are very good reasons to believe in the many worlds interpretation of quantum mechanics. Schrodinger's equation of quantum mechanics is the most successful equation there is for how the universe works and it already contains the so called "many worlds" (aka superpositions - e.g. Schrodinger's cat being both alive and dead). The many worlds interpretation is the simplest one - to just believe what the equation says; it's all the other interpretations that try to somehow make those superpositions/worlds disappear when a measurement is made, for example by adding an additional rule saying that the wavefunction somehow collapses, because many people are uncomfortable with the idea that all those possibilities could be real.

[@Tore_Lund]

@@Neme112 Yes, many worlds as the solution to indeterminism.

[@naturalscience2022]

The guy who switch me from engineer to work as a high school physics teacher.❤

[@markxxx21]

This guy is really, really, REALLY good at explanations

[@manojitkapat3415]

Absolutely brilliant talk. Touched my heart . Thank you sir.

[@solarian_13]

One of the biggest things that kept me out of physics as a career was the math I thought I could never ever get down. Sean absolutely makes the math digestible and makes its application seem so easy to follow. Wish he was my high school math teacher; I might just have become a physicist!

[@JasynE]

Fantastic presentation Sean! Thank you for bringing cosmology so close to the rest of us so that we may appreciate it too.

[@MaryAnnNytowl]

This was absolutely riveting for me! I mean, a good portion of it went a bit over my head, but I _got_ enough of it for this to really be enjoyable! Thanks!

[@mighty8357]

He is so good at explaining things!

[@robertgoss4842]

Three cheers for Dr. Carroll. In this lecture, he displays all the finest qualities of an excellent teacher. He presents some of the knottiest issues in physics in an understandable, non-threatening way. He shows great respect for his listeners by liberally tossing around some very complex equations, carefully explaining each one. I'm just a bohunk Georgia boy, but I never miss Dr. Carroll's lectures, and indeed, often find myself viewing them a second and third time.

[@BernardWei]

Perfectly digitally rendered on the Kindle version if you can't get your hands on the hard copy. He is a genius in explaining a difficult subject, a deeper understanding of space and time that can only be had by going through the concise formulation.

[@TheMaxwellee]

I feel like I've heard a lot of this before, but the way you say it is excellent. Thank you.

[@latifdiallo3814]

Extremely brilliant as always. Sean explains so much better. I understood way better and will be looking forward to more lectures from Sean. The univers is just beyond incridible

[@klammer75]

Amazing! One of the best presentations of GR I’ve seen! Thank you sir!🤓🥳🤩

[@skyjump6750]

Absolutely brilliant talk. Thank you very much.

[@steveseamans9048]

Your best on the subject so far. I am super into all your podcasts etc. keep up your work. It’s very important.

[@user-oy4kd3zb3z]

Most lucid explanations of recondite concepts and relations by Sean Carroll. Thank you.

[@lenny7989]

This was by far the best leture on this Subject I've listened to.Thanks Sean!

[@quantumcat7673]

I love that presentation! Sean Carroll wisdom gets better by the years.

[@wailinburnin]

I got it all, perfect understanding, and then came the instantaneous applause and I lost it. How and where did the applause come from?

[@Edwinvangent]

after listening to Sean I think now 50 times, all different lectures. The picture in my head becomes more and more complete. I am not a mathematician (like Einstein lol) I do kind of get it now, I remember that a long time ago I set myself a goal that if I get the change I would try to understand Einstein's theories. And I feel that I am getting there, so thx Sean and You Tube. And now I think I will order your book.

[@Dr.RiccoMastermind]

Really well explained!! Never seen this topic like this. I want more of him!! It seems so.... understandable 😅

[@ThunderBassistJay]

Very clear presentation. Much appreciated! 🙏

[@aaronh920]

It's all very interesting. I will need to watch this again after some consideration.

[@stephanieparker1250]

Great lecture, Sean 😊😊 looking forward to getting the new book! 🎉

[@vittorio13ful]

Great Sean!!! ⭐️⭐️⭐️ the best in talking about psysics in an easy way 👍🏼

[@jarmomarkkanen2473]

Really great presentation, thank you for doing this.

[@lanaiwolftail7263]

I really love listening to the learning and speed up on reading.

[@georgeblau1072]

Thanks for that well explained connections we should plant into our brains now. It is very inspiring and leads to dive into the math more manually than just accepting the theory.

[@penklislawnmowing4508]

A very well put together lecture for everybody to understand. My biggest aim is to give people the chance to compete in events who never did good at school or sport. This is a very good general knowledge lecture and so are a lot of the other lectures from The Royal Institution.

[@RWBHere]

So, in a nutshell, the equation presented in Slide 2 predicts Black Holes, gravity waves, and much more. Brilliant! Thank-you. We'll be wrestling with some of this for a long time.

[@RemiStardust]

This is about as well explained as is possible. Impressive.

[@DamianReloaded]

Very nice! Kudos for the book!

[@markus4925]

Thx. Very good video. Pure genius explanation

[@KhanhNguyen-ew6gq]

Thank you! You provided the most comprehensive, most intuitive explanations for one of the most iconic and complex equations: Einstein Field Equations! 🙂

[@georgeblau1072]

Danke! With those YT videos Ri contributes to global, individual knowledge by providing very interesting subjects which are very well prepared and thus easy to follow.

[@TheRoyalInstitution]

We're very glad you like them!

[@myopenmind527]

Sean Carroll on RI……must be my Birthday or Santa 🎅 has come early 😁.

[@subhanusaxena7199]

Awesome talk, was hoping you would explain the Cosmological Constant too!

[@roku-device23]

Very, very good. You helped me see something with a brand new perspective. Thank you.

[@andyiswonderful]

What a great communicator.

[@plbyrne]

The best science speaker by far.

[@ChrisFaa]

Excellent!! Thank you.

[@benbrill3617]

Still stunned by how good this lecture is. The way Sean intersperses history and his use of graphics to communicate an idea works really well. Whatever it is you’re doing Sean, please don’t stop. Request, if I may be so bold, I’ve been trying for a couple of years to understand how Planck solved the, at the time, 40 year old Blackbody problem problem but to no avail. An explanation of how he solved it without using any of the nomenclature, words, ideas, or concepts that came into being post 1900.

[@fennercolson8680]

Great presentation!

[@user-og4fk6os1r]

Wow this was phenomenal. I've been casually following modern pbysics since college and have never seen an approachable explanation of GR before that actually follows the math. Sean Carroll is a national treasure.

[@richardcasey4439]

Superb explanation of a challenging topic

[@nacnud_]

I saw this guy live at Glasgow Uni. Very engaging fella. Thanks, as ever.

[@glenndarrington4677]

Well done!!!

[@ricke6854]

That was an amazing presentation.

[@brianelliott9861]

Totally fascinating

[@thedduck]

Aww man, love this guy, sucks that he can't be there in person.

[@katg-gk5ox]

What a nice surprise! In the middle of an introductory GR class right now :). I Definitely need to get this book! Riemann a student of Gauss. Oh that wouldn't be intimidating at all! :)

[@tusharkumar3809]

an awesome presentation !

[@chunkynorris100]

That was really helpful actually, I'm thinking of studying geometries now

[@LEDewey_MD]

Great presentation! :)

[@blablah6763]

Love Sean. Thanks!

[@hazembiqaeen]

Sean does a good job as a teacher

[@alcyone1349]

Thanks Sean

[@armchairgravy8224]

Since you're including the math I'll check out the book. I don't always understand the math, but I do like to see it in hopes one day I will finally get it.

[@gowthamkudupudi1012]

Thanks!

[@mjgbirder]

Excellent presentation… :-) So good I feel like I actually understood it… M

[@PlanetXMysteries-pj9nm]

"Your channel is something very very special. Top 3 on KZbin for this type of programming in my opinion. It boggles my mind almost as much as the information you provide in the shows, how you only have half a million subscriber’s. I feel like I’m getting in early on a community with the potential to reach 10 million subscribers or more. Just fantastic ground breaking work you’re doing here my friend. I’m honored to be a part of it. I will be making donations to the channel going forward. Thank you for what you’re doing from Canada. 🙏💫🇨🇦🍻"

[@sureshdeshpande6281]

No nice to listen to Prof Carroll. He is an excellent teacher and researcher.

[@smlanka4u]

Prof. Sean Carroll knows what he talks about. 🙏

[@fieryweasel]

I love the bit around 39:10, "Skipping some steps...guess what?"

[@davidrobertson-oj9tr]

Thank you to Sean. He has put these ideas clearly and freely into the public domain I understand why it is so complicated and has been difficult for people to make use of it I appreciate that some people devote a lot of time and study to make use of it Maybe this is artificial intelligence and not the first. Something we create that s smarter than we are Brilliant

[@TunaFreeDolphinMeat]

Great teaching

[@W00PIE]

Great to see him back in the RI. I wish other scientists would dare to show the real math behind these concepts. If you keep hiding them, things will never change. Bold move to explain the Riemann tensor in less then 53 minutes 😃

[@tatotato85]

Sean podcast its currently at his 218 episode, i highly recommend people to check it out, its full of gems

[@mattewgeorg2799]

It's really amazing lecture. And it's very important how to correctly to interpret Einstein's equations in GR. We can see also: Rethinking the Formal Methodology (II): Cognitive Content of Relativity (On the Centenary of General Relativity)

[@AndreaCalaon73]

Well done prof. Carroll! I like your simplification way through GR. I think that the geometrical meaning of Ricci's tensor and scalar should be better explained (in general). Possibly as the first "Taylor terms" (constant and first linear term) of the expansion of the "curvature state". Probably Geometric Algebra could help. I think that the full Riemann's tensor is unnecessary and cumbersome. Have a beautiful day!!

[@Twobarpsi]

Great video!!

[@DanHonnen]

Thank you to Sean for using a good microphone! I love The Royal Institute's videos, but most of these remote ones have painfully terrible audio, so I quickly lose my motivation to watch them, this one, not so much!

[@zack_120]

1:17- enlightening revelation that is why you are the best sci educator

[@dr-gb3tq]

Perfect💯

[@grumpyed58]

Impressive presentation

[@ytrrs]

Sean Carroll makes me feel that Mathematical Physics, Tensor Calculus and GTR are not that difficult at all. I wish my professor in physics class made me feel that way, years ago! 🙂

[@benjamindover4337]

Excellent

[@curteaton8162]

Thank you for making this so understandable. Even though I may not be able to do the math or even want to do the math. Understanding how it all works and what the math is trying to say. I can now appreciate the strugle that is going on in the world of physics. Maybe my theory of ST1 dimention and the TS1 dimention entertwined together beeing respocible for the quantum foam that we expolor today and will show up one day described by the math. Then prove I was right all along. This is a fun ride. Thank you.

[@alex79suited]

Great video.

[@satishgupta2658]

Love from Nepal 🇳🇵.

[@jackievanerelli2122]

Sean, thanks for mentioning Leibniz! Nobody ever does when explaining gravity and physics.

[@nrbanerjee9274]

A commendable lecture indeed, wherein so many aspects have been addressed in perfect sequence. Many thanks Dr Sean…. Just for a clarification, could you throw some light, if the change of entropy ( the ever changing and non stoppable disorder in any closed systems) could be correlated with concept of time in eternity…..

[@Gerrytubeable]

Bedankt

[@scotvaka1t375]

Thank you for the excellent explanation. Now I know the problem with our current physics. We have built on a foundation that doesn't quite match observations of nature. Newtons postulates. The solution is going back and refining Newton's postulates to be more accurate descriptions of nature. Fyi, Walter Russell has already done this.

[@brothermine2292]

1. I'm a traditionalist... I prefer seeing c or c squared explicitly in relativity equations, rather than ”oversimplifying” by setting c=1 as Sean did in this video. 2. The minus sign in the Minkowski ”pythagorean” equation can be eliminated by subtracting the negative term(s) from both sides of the equation. (That moves the negative term from the right side of the equal sign to a positive term on the left side, so that all the terms are positive.) This leads to a truly pythagorean equation. (With the minus sign, it's actually a hyperbolic equation, not pythagorean.) With a bit of algebraic manipulation, you can arrive at a pythagorean equation where the hypotenuse of the right triangle is the speed of light c, and the other two sides of the right triangle are an object's velocity through 3-dimensional space and the object's rate of aging. The interpretation of the equation is that everything -- including light, and including you & me -- is traveling through 4-dimensional Minkowski spacetime at the same speed c that light travels through 3-dimensional space. That ”speed of everything” has the aroma of a fundamental equation... one that I wish I'd been taught when I was young.

[@kylelochlann5053]

It'd be a good idea to learn to take c=1 to fully understand relativity. You can certainly swap the proper and world-time to make the equation exactly pythagorean if form (a "mixed" coordinate form or my-space-their-time metric) but this doesn't change anything. Note: It is true that the tangent vector to any world-line norms to the speed of light, but extending this to the light itself is, well a little bizarre, as there is no proper time affine parameterization of a null curve.

[@brothermine2292]

@@kylelochlann5053: 1. How does setting c=1 help one ”fully understand” relativity? Isn't it just a convenient choice of unit that makes the equation look simpler, but obscures an important piece of physics information? 2. I don't see why you're quibbling about “extending“ it to include light. The implication of the equation is that light doesn't age... all of its travel in 4D spacetime is confined to 3D space. Objects age more slowly as their speed through 3D space increases, and the limit is zero aging as an object's speed through 3D space approaches the speed of light.

[@kylelochlann5053]

@@brothermine2292 No, it's the exact opposite. Relativity understood through the causal structure of the gravitational field is deeply illuminating as to what is going on. Setting c=1 is measuring time in terms of length. If you take a graduate level (or advanced undergrad) textbook you'll see that distance, time, mass, energy, and electric charge are all measured in meters (or the length units of your choice). For example understanding time dilation and the clock effect and properties of black holes is an entirely different experience when understand in the context of spacetime foliation and distances along world-lines, and experience that is more clear and in alignment with common sense.

[@brothermine2292]

@@kylelochlann5053 : I guess we disagree on what it means to ”fully understand.” Choosing a convenient scale factor can make some relationships easier to see due to limitations of human cognition, but that simplification has a cost. I would conjecture that an AI (or augmented human mind) would be able to see those relationships as clearly without the crutch of setting c=1, and I would call this a fuller understanding. It's the advanced math tools (differential geometry, etc) that offer a deeper understanding, not setting c=1.

[@kylelochlann5053]

@@brothermine2292 Setting c=1 has nothing to do with scale factors and is emphatically not a scale factor. It is a fundamental shift in the meaning of the equations. Instead of explaining this, which you're clearly not understanding, explain to me how it is that given two clocks, one of which remains and rest and another taken on a journey around campus come back reading different elapsed times? What is happening to the clocks?

[@williamselby314]

amazing

[@sarcasmo57]

I'm glad there are people much smarter than me around.

[@123fiona456apple789]

Awesome,

[@dansloss2566]

Mind expanding, just like the expanding universe. Thank you. DId you mean 1930s or 1830s at 21:49? Bravo on your presentation.