The biggest ideas in the Universe - with Sean Carroll

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  • čas přidán 20. 11. 2022
  • 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
    Subscribe for regular science videos: bit.ly/RiSubscRibe
    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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Komentáře • 463

  • @guywebber9312
    @guywebber9312 Před rokem +119

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

    • @manicmadpanickedman2249
      @manicmadpanickedman2249 Před rokem

      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
      @manicmadpanickedman2249 Před rokem

      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
      @Mizzkan Před rokem

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

    • @manicmadpanickedman2249
      @manicmadpanickedman2249 Před rokem

      @@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
      @redneckshaman3099 Před rokem

      I'm addicted to pigger nussy 😻

  • @MichaelEhling
    @MichaelEhling Před rokem +81

    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
      @hamidmazuji Před 7 měsíci +1

      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
      @MichaelEhling Před 7 měsíci

      @@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
      @hamidmazuji Před 7 měsíci +1

      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
      @hamidmazuji Před 7 měsíci +1

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

    • @hamidmazuji
      @hamidmazuji Před 7 měsíci

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

  • @biffy7
    @biffy7 Před rokem +19

    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.

  • @ashcross
    @ashcross Před rokem +40

    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.

  • @peterwan9076
    @peterwan9076 Před rokem +8

    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.

  • @DudokX
    @DudokX Před rokem +19

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

  • @Sileonex123
    @Sileonex123 Před rokem +107

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

    • @alexanderabrashev1366
      @alexanderabrashev1366 Před rokem +6

      I'm the same with Brian Greene

    • @PetraKann
      @PetraKann Před rokem +1

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

    • @CorezMon
      @CorezMon Před rokem +6

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

    • @htopherollem649
      @htopherollem649 Před rokem +3

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

    • @ce5834
      @ce5834 Před rokem +1

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

  • @vinodt1347
    @vinodt1347 Před rokem +3

    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
      @Seekthetruth3000 Před rokem

      Did you get it back?

    • @beeble2003
      @beeble2003 Před 6 měsíci +1

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

  • @naturalscience2022
    @naturalscience2022 Před rokem +9

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

  • @JiminiCrikkit
    @JiminiCrikkit Před rokem +20

    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

  • @minivanjack
    @minivanjack Před rokem +10

    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
      @HarryNicNicholas Před rokem +1

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

    • @Tore_Lund
      @Tore_Lund Před rokem

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

    • @Neme112
      @Neme112 Před rokem

      @@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
      @Tore_Lund Před rokem

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

  • @markxxx21
    @markxxx21 Před rokem +7

    This guy is really, really, REALLY good at explanations

  • @bluesque9687
    @bluesque9687 Před rokem +10

    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!!

  • @solarian_13
    @solarian_13 Před rokem +11

    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!

  • @shantanulokhande3730
    @shantanulokhande3730 Před rokem +34

    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
      @REDPUMPERNICKEL Před rokem +2

      Simple, not simplistic. Simplistic is derogatory.

    • @shantanulokhande3730
      @shantanulokhande3730 Před rokem +1

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

    • @REDPUMPERNICKEL
      @REDPUMPERNICKEL Před rokem

      @@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
      @necktwiozfguah8818 Před rokem

      James Beacham is my favourite

    • @citizen240
      @citizen240 Před rokem +1

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

  • @BernardWei
    @BernardWei Před rokem +8

    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.

  • @wailinburnin
    @wailinburnin Před rokem +2

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

  • @robertgoss4842
    @robertgoss4842 Před 3 měsíci

    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.

  • @MaryAnnNytowl
    @MaryAnnNytowl Před rokem +8

    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
    @mighty8357 Před rokem +29

    He is so good at explaining things!

  • @RWBHere
    @RWBHere Před rokem +3

    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.

  • @JasynE
    @JasynE Před rokem +34

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

  • @manojitkapat3415
    @manojitkapat3415 Před rokem +17

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

  • @thedduck
    @thedduck Před rokem +5

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

  • @user-oy4kd3zb3z
    @user-oy4kd3zb3z Před 10 měsíci +1

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

  • @Edwinvangent
    @Edwinvangent Před rokem +4

    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.

  • @user-og4fk6os1r
    @user-og4fk6os1r Před 4 měsíci

    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.

  • @tatotato85
    @tatotato85 Před rokem +1

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

  • @latifdiallo3814
    @latifdiallo3814 Před rokem +4

    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

  • @skyjump6750
    @skyjump6750 Před rokem +7

    Absolutely brilliant talk. Thank you very much.

  • @katg-gk5ox
    @katg-gk5ox Před rokem +6

    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! :)

  • @TheMaxwellee
    @TheMaxwellee Před rokem +1

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

  • @benbrill3617
    @benbrill3617 Před rokem +3

    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.

  • @roku-device23
    @roku-device23 Před 5 měsíci +1

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

  • @klammer75
    @klammer75 Před rokem +2

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

  • @aaronh920
    @aaronh920 Před rokem +5

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

  • @PlanetXMysteries-pj9nm
    @PlanetXMysteries-pj9nm Před 6 měsíci

    "Your channel is something very very special. Top 3 on CZcams 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.
    🙏💫🇨🇦🍻"

  • @Dr.RiccoMastermind
    @Dr.RiccoMastermind Před rokem +4

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

  • @georgeblau1072
    @georgeblau1072 Před rokem +4

    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.

  • @steveseamans9048
    @steveseamans9048 Před 8 měsíci

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

  • @stephanieparker1250
    @stephanieparker1250 Před rokem +1

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

  • @lenny7989
    @lenny7989 Před 4 měsíci

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

  • @sureshdeshpande6281
    @sureshdeshpande6281 Před rokem

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

  • @andyiswonderful
    @andyiswonderful Před rokem +2

    What a great communicator.

  • @myopenmind527
    @myopenmind527 Před rokem +4

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

  • @ytrrs
    @ytrrs Před rokem +1

    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! 🙂

  • @plbyrne
    @plbyrne Před rokem +2

    The best science speaker by far.

  • @RemiStardust
    @RemiStardust Před rokem +1

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

  • @davidrobertson-oj9tr
    @davidrobertson-oj9tr Před rokem +1

    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

  • @fieryweasel
    @fieryweasel Před 8 měsíci

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

  • @quantumcat7673
    @quantumcat7673 Před rokem

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

  • @lanaiwolftail7263
    @lanaiwolftail7263 Před rokem +1

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

  • @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.

  • @W00PIE
    @W00PIE Před rokem +9

    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 😃

  • @vittorio13ful
    @vittorio13ful Před rokem

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

  • @nacnud_
    @nacnud_ Před rokem +1

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

  • @zack_120
    @zack_120 Před 7 měsíci

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

  • @armchairgravy8224
    @armchairgravy8224 Před rokem +2

    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.

  • @jackievanerelli2122
    @jackievanerelli2122 Před 7 měsíci

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

  • @jarmomarkkanen2473
    @jarmomarkkanen2473 Před rokem

    Really great presentation, thank you for doing this.

  • @DamianReloaded
    @DamianReloaded Před rokem +1

    Very nice! Kudos for the book!

  • @georgeblau1072
    @georgeblau1072 Před rokem

    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.

  • @chunkynorris100
    @chunkynorris100 Před rokem +4

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

  • @subhanusaxena7199
    @subhanusaxena7199 Před rokem +2

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

  • @KhanhNguyen-ew6gq
    @KhanhNguyen-ew6gq Před rokem

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

  • @LEDewey_MD
    @LEDewey_MD Před rokem +3

    Great presentation! :)

  • @markus4925
    @markus4925 Před rokem

    Thx. Very good video.
    Pure genius explanation

  • @fennercolson8680
    @fennercolson8680 Před rokem +1

    Great presentation!

  • @ChrisFaa
    @ChrisFaa Před rokem

    Excellent!! Thank you.

  • @alcyone1349
    @alcyone1349 Před rokem

    Thanks Sean

  • @mjgbirder
    @mjgbirder Před rokem +1

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

  • @tusharkumar3809
    @tusharkumar3809 Před rokem

    an awesome presentation !

  • @blablah6763
    @blablah6763 Před rokem

    Love Sean. Thanks!

  • @brianelliott9861
    @brianelliott9861 Před 4 měsíci

    Totally fascinating

  • @glenndarrington4677
    @glenndarrington4677 Před rokem +1

    Well done!!!

  • @sarcasmo57
    @sarcasmo57 Před rokem +1

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

  • @richardcasey4439
    @richardcasey4439 Před rokem

    Superb explanation of a challenging topic

  • @gowthamkudupudi1012
    @gowthamkudupudi1012 Před rokem

    Thanks!

  • @ricke6854
    @ricke6854 Před rokem

    That was an amazing presentation.

  • @smlanka4u
    @smlanka4u Před rokem

    Prof. Sean Carroll knows what he talks about. 🙏

  • @Twobarpsi
    @Twobarpsi Před rokem

    Great video!!

  • @roberthutchison8197
    @roberthutchison8197 Před rokem +3

    I can describe all this in 5 words; It's all Greek to me! For some reason I just love reading about things like this even if I understand none or very little about it...

  • @afedden
    @afedden Před 25 dny

    Excellent. I'm much the wiser on tensors now.

  • @DanHonnen
    @DanHonnen Před rokem +1

    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!

  • @hazembiqaeen
    @hazembiqaeen Před 8 měsíci

    Sean does a good job as a teacher

  • @alex79suited
    @alex79suited Před 11 měsíci

    Great video.

  • @mattewgeorg2799
    @mattewgeorg2799 Před rokem

    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)

  • @TunaFreeDolphinMeat
    @TunaFreeDolphinMeat Před rokem

    Great teaching

  • @polyrhythmia
    @polyrhythmia Před rokem +1

    Symmetry does help simplify a bit, taking sixteen equations down to ten.

  • @helgefan8994
    @helgefan8994 Před rokem +1

    37:25 You're not quite a member of the last generation who had to calculate these tensors by hand. A few years ago I learned tensor algebra at a German university from a stern Russian professor who still made us calculate these entries by hand during exams.
    It was in the context of continuum mechanics instead of General Relativity, but it's still the same kind of mathematics with Einstein's summation convention and stuff.
    Believe it or not, some of what I learned in that course is still useful to me, as I keep impressing some of my colleagues at work with it every now and then by finding neat solutions with it. :)

  • @grumpyed58
    @grumpyed58 Před rokem

    Impressive presentation

  • @curteaton8162
    @curteaton8162 Před 11 měsíci

    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.

  • @scotvaka1t375
    @scotvaka1t375 Před rokem +2

    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.

  • @benjamindover4337
    @benjamindover4337 Před rokem +1

    Excellent

  • @AndreaCalaon73
    @AndreaCalaon73 Před rokem +2

    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!!

  • @brothermine2292
    @brothermine2292 Před rokem +3

    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
      @kylelochlann5053 Před rokem

      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
      @brothermine2292 Před rokem +1

      @@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
      @kylelochlann5053 Před rokem +1

      @@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
      @brothermine2292 Před rokem

      @@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
      @kylelochlann5053 Před rokem

      @@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?

  • @ianmichael5768
    @ianmichael5768 Před rokem

    He is an honest man.
    I wonder if this is how Feynman felt when he tried teaching people his diagrams?
    I do miss the blackboards.

  • @Gerrytubeable
    @Gerrytubeable Před rokem

    Bedankt

  • @123fiona456apple789
    @123fiona456apple789 Před rokem

    Awesome,

  • @TheOriginalKayo
    @TheOriginalKayo Před 10 měsíci

    I was today years old when I finally understood the math in the physics I love so much. Lol