#science #physics #ideas The Biggest Ideas in the Universe | 1. Conservation

#science #physics #ideas The Biggest Ideas in the Universe | 1. Conservation 244,109 viewsMar 24, 2020 8.1K DISLIKE SHARE DOWNLOAD CLIP SAVE Sean Carroll 154K subscribers [Correction: at 17:51 I say kinetic energy is a vector, I meant to say "scalar." Kinetic energy has a size, but doesn't point in a direction.] The Biggest Ideas in the Universe is a series of videos where I talk informally about some of the fundamental concepts that help us understand our natural world. Exceedingly casual, not overly polished, and meant for absolutely everybody. In this installment - the very first idea we cover! - I talk about "Conservation." The idea that a certain property, like momentum or energy or electric charge, stays the same over time. In my view, realizing that this is true - and the corollary, that the world naturally moves, rather than needing something external to keep it moving - represents the real transition between pre-modern and modern physics. My web page: http://www.preposterousuniverse.com/ My YouTube channel: https://www.youtube.com/c/seancarroll Mindscape podcast: http://www.preposterousuniverse.com/p... The Biggest Ideas playlist: https://www.youtube.com/watch?v=HI09k... Blog posts for the series: http://www.preposterousuniverse.com/b... Background image: https://www.jpl.nasa.gov/missions/voy... #science #physics #ideas #universe #learning #cosmology #philosophy #math #conservation #momentum #energy #classicalmechanics 636 Comments rongmaw lin Add a comment... ohmultiverse ohmultiverse 1 year ago Some people's personalities just...shine. Or rather, they shine through. One only has to watch Sean Carroll for a little while to know, to a high degree of certainty, that he is not only highly intelligent, but also that he has a wonderful wit, is a kind human being, is fundamentally optimistic, and is thoroughly unpretentious. Thanks so much for creating this series Dr. Carroll. 76 Fascinating Facts Fascinating Facts 2 years ago This is awesome Sean. Thanks for the content. 120 ratedAD ratedAD 2 years ago (edited) Sean, please keep doing this! You truly have a gift. Love your work and your passion for educating the uninitiated. I'm 36 and deeply regret not taking physics more seriously growing up. Your lectures and videos are such a source of intellectual nourishment for me. I am a regular listener of your Mindscape podcast and a Patreon supporter. Please keep producing more work that benefits people like me who are not trained in the math but are curious about the big questions nonetheless. Cheers! Please stay safe! 11 Martin DS Martin DS 2 years ago Loving this new series, thanks a lot Sean. This kind of content really helps to get through our current global situation. 8 TheKoopaKing TheKoopaKing 2 years ago Loved it but it was too short! I would've loved to hear about Noether's theorem and how conservation connects to higher level physics. 30 Justin Highley Justin Highley 2 years ago I rarely ever comment on anything on youtube, but I just wanted to let you know that i LOVE listening to you. I think NDT gets a ton of admiration and praise (rightfully so) for being the best at teaching/discussing REALLY intelligent ideas to the basic public in a way that is fun, desirable and educational. But you make me yearn for more, you make it SO exciting and so easy to develop a desire to want to understand more about physics. You and Brian Greene are my hero's! I think i may have chosen the wrong field for my career! :( #iwannabeaphysicists. 6 Vojoo Vojoo 2 years ago (edited) Pro tip: I don't know what you are using for video editing but somewhere you should be able to adjust the colours. Lower the green values, maybe cyan. That's an easy way to clean up the edges and even the light scatter. Greetings from Germany, keep it up! 17 In Dream In Dream 2 years ago (edited) Im so happy!!! Thank you for all you do and for starting here with Conservation of momentum. When Neil deGrasse was asked about the most counterintuitive, peculiar law of physics and I was wondering what will he say, that would feel more stranger to me than that. Whatever he said was not as impressive for me as to why things just keep moving unless any of its energy is exchanged and why moving through a vacuum is free. It just seems like a key to something. Well, just a minute into the video, excited to learn something! Thank you again! 4 Tom Johnson Tom Johnson 1 year ago Great work sean, thank you for taking time to make these podcasts. And for educating this generation and hopefully future generations to come, thanks from Ireland ☘ 1 Felipe Monteiro Felipe Monteiro 2 years ago Excelent content as usual, Sean! Thank you! I learned a lot, and look forward to the next ones! 2 Jason Jason 2 years ago Awesome video, Sean. Thanks for making these! Can't wait for more! 4 Bill Lyons Bill Lyons 2 years ago Your videos are a bright spot in this crisis. Thanks for making them. 45 TheVulcanJedi TheVulcanJedi 2 years ago This is gold! Thank you very much for doing this series. I learned a lot. 1 Killington Killington 2 years ago Awesome video! Very entertaining and educational. Loving hearing the stories of the history and philosophy behind the ideas, also love the enthusiasm for the subject! 1 quazzie1 quazzie1 2 years ago Love what you're doing. Keep 'em coming, Sean ! Luiz Gustavo Rocco Luiz Gustavo Rocco 2 years ago Great video professor, I'm proud we are popularizing science through YouTube and other medias nowadays, keep up the good work! 1 SatanDynastyKiller SatanDynastyKiller 2 years ago This was a great start, thank you very much Sean. Can’t wait for the rest. 9 Lycakito Lycakito 2 years ago This is great, while at home, physics lessons from the greatest! Thank you ! 1 tripp tripp 2 years ago This is a fantastic video and series, Sean. Thank you! Bruce Neeley Bruce Neeley 2 years ago Excellent talk, for being a non science historian you did an amazing job explaining the evolution of thought regarding the topic. The visuals work great. I'm looking forward to future installments. Stelios P Stelios P 2 years ago (edited) Dr. Caroll, thank you so much for your podcast, books and your Youtube channel. Love your work and thank you for being such an incredible communicator of science. All the very best to you and your family. Integza Integza 2 years ago (edited) I love this! Great idea! It's an honor to have you here on YouTube, Sir. KN Carnage KN Carnage 2 years ago Thanks so much for these “lessons”. I love watching them 1 Jim Graham Jim Graham 1 year ago Your time, expertise and effort in making this series is much appreciated. Spencer Allbritton Spencer Allbritton 1 year ago (edited) Thanks Sean! I love your content and have been listening to you for a while now. I’d love to listen to two videos on Entropy and Noether’s Theorem. xViolatorx xViolatorx 2 years ago I enjoyed this episode very much, looking forward to the next one! 1 rick johnson rick johnson 2 years ago Thank you Sir! Your podcast is making this new reality of "social distancing" / "self isolation" interesting and entertaining! :) I appreciate what you are doing. P.S. if you can find a reason to have David Albert back on the podcast that would be fantastic! mr man mr man 2 years ago thank you for making these videos! you have inspired me to dust of the old physics text books for a little refresher! thank you :) mrlithium mrlithium 2 years ago Thank you for doing your part explaining complex topics and making your mark on the internet. In the information age, this will live on forever and in the future you may even be regarded as a modern Aristotle-type thinker from the 21st century. Cogito, ergo sum. 2 Claus Marcuslund Claus Marcuslund 2 years ago I think your channel is going to become just great - keep pushing, keep it moving! 1 David Werfelmann David Werfelmann 2 years ago (edited) Awesome video! My question: You mentioned that momentum is in some sense a property or characteristic of an object. Is there a way to quantify momentum (mass X velocity) in the absence of a spatial frame of reference? I can see how the mass can be quantified, but I don't see how the velocity can absent some external frame (like, the ground or then sun, etc.). And if momentum can't be quantified without the frame, then in what sense does it really exist? THANKS! 1 Jerome Gouvernel Jerome Gouvernel 2 years ago Awesome, thank you. Would love a video on inertia. Where does it come from? What is the nature of it? David le Viseur David le Viseur 1 year ago Absolutely brilliant, deeply thoughtful and lucid in so many ways! 1 Ronan Mehigan Ronan Mehigan 2 years ago Thank you - great start to the lecture series. Can you discuss how conservation of momentum is related to the fact that the laws of nature are symmetrical with respect to spatial linear translations ? WASIM SHAIKH WASIM SHAIKH 2 years ago (edited) Man u deserve a Nobel prize for your explainations👏👏 I wish my physics teacher was like him🤔 2 Daniel Harris Daniel Harris 1 year ago I’ve only watched the first episode but I loved it and can’t wait to watch the rest you’ve released. Thank you so much for taking the time to make these. Superluminal Superluminal 2 years ago Thank you, Sean! Please keep them coming! constellationpegasus constellationpegasus 2 years ago Thank you Sean. I’m happy and excited about these upcoming videos. Thank you very much sir. Lightning Lance Lightning Lance 2 years ago Loved it. The spherical cow philosophy is now my favorite explanation as to why math/physics is so unexpectedly succesful in describing the world around us. William Knudsen William Knudsen 2 years ago Thank you for posting. This helps keep sanity in this era we are living through. Yerva Yerva 2 years ago Very interesting and educative. Thank you! 1 saad Z saad Z 2 years ago Thanks Sean..great content as usual! Isa ahmad Isa ahmad 2 years ago Thank you Sean. This was absolutely magnificent. Tcb Bct Tcb Bct 2 years ago After I get home from working at the hospital your videos really help me get my mind off of what's going on. Thank you Sean. Not that it's really relevant to this particular video but Im sort of starting to understand the concept of a superposition and that's all you bud! kiba vlood kiba vlood 2 years ago Sean i came from the Joe Rogan episode where you literally blew my mind when you said that even though you make a simulation that predicts everything the choices a human make inside is totally random and still is unpredictable. It went something along those lines. That and also Laplace's Demon. I was always interested in Science but my teachers and professors made a nightmare out of it. I gave up the interest and curiosity i once had but thanks to you i rekindled that curiosity. Also i love the way you explain stiff so easily and simple. Take care of yourself in this hard times. Love to learn something new from your videos. 1 Kimberly Johnson Pemberton Kimberly Johnson Pemberton 4 months ago (edited) Obsessed with the intellects! Thank you for the lessons, making it accessible to those of us that have no background, the patience involved with this and hitting so many areas the vast majority of us are curious on but had no way of knowing where to start. I crave the day that all ladies understand intellectual power over brute force. These are our lovers, the others are cavemen yuck 🙈🙉 Xavier Gamer Xavier Gamer 2 years ago I love this new series. Thank you. 1 Analytics Group Analytics Group 2 years ago Love the video's! When are you doing a new course on TTC? I did follow the " older" counrces but it would be so cool to have the new insights that are there now! Ernest G. Wilson II Ernest G. Wilson II 2 years ago First let me say thank you very much for taking the time to make these videos and share them with all of us. I couldn't help but notice you went from Galileo to Isaac Newton and skipped over Johannes Kepler. Thank you very much for the explanation on BCE and CE as this is much preferred over BC and AD. I am of course subscribed with notifications turned on and thumbs up. The Norseman The Norseman 2 years ago You, Dr. Carroll, are a worthy candidate to be this newest generations' "Great Explainer." Please accept this humble gift of an imaginary Spherical Feynman to sit proudly next to your Cow. 79 juraowen juraowen 2 years ago Love this! Is it accurate to say that the laws of physics are simply descriptions of very regular patterns in the universe? Is the scientific community essentially looking for and attempting to accurately describe regular patterns? Or have I misunderstood? 1 chris tinley chris tinley 2 years ago Such a great break down of this..you've bin teaching me for years now...I actually know things!!! Lol. Thank you..keep em coming:) Adrian Tabirca Adrian Tabirca 3 months ago Amazing. I wish I had you as a physics teacher in my middle and high school. peter jansen peter jansen 1 year ago I can listen to you for hours! great talks, sensible and understandable Walter Lau Walter Lau 2 years ago (edited) I'm stoked for this series! I had no interest in physics while I was attending school. All of my interest has come from youtube. This format feels like you are teaching in ways that I can wrap my head around. There was an inelastic collision when you uploaded this video. Some of the energy that you put into this video was converted into a subscription from me. right? Mohit Bansal Mohit Bansal 5 days ago This is more meditation than education. Thanks Sean 👏 Rizwan Nazir Ahmed Rizwan Nazir Ahmed 7 months ago Professor, you are my favorite physicist on the planet, I intend to make a similar series for physics below graduate level, since I am a graduate student myself, actually been wanting this on youtube for a long long time, but now I am actually going to do it, wanted to know what software or app facility do you use for the text and yourself to be shown at the same time? Christopher Wilson Christopher Wilson 1 year ago Great video, explaining concepts with as much history as possible, using history to explain them is just the best. Thank you! You should consider guest host to take over in case you run out of time with too many projects. CharlesDavid CharlesDavid 2 years ago Thank you for this awesome series!! Kim Conger Kim Conger 2 years ago (edited) I do recall this discussion from The Big Picture, but I appreciate the relationship you have identified here between the sort of deterministic approach to the universe and the uprising of the spherical cow philosophy. I suppose Ibn Sina was nearly the equivalent of a "prime mover" in these domains. ;-) 2 Nick Morgan Nick Morgan 1 year ago Thank you Sean. You are really leaving some wonderful things for today's generations and future ones alike. I especially like your take on the purpose of physicists and the way you have not been scared to delve into the world of the implications of quantum mechanics. There is no doubt that you will be the inspiration for countless physicists to come! Thanks again for the exceptional content. 1 sean mortaz sean mortaz 2 years ago Fantastic. Love these informal series!!! nbvw3 nbvw3 1 year ago Fantastic series, thanks a lot for the time you are taking! (BTW, the bit on Laplace's Demon reminded me of that TV show, "Devs" - if that's not a terrible thing to say) Mohammad Khan Mohammad Khan 2 years ago Can you please also explain the conservation of momentum and energy in special relativity? Luke Curran Luke Curran 1 year ago Thanks Sean so much for this series. I didn't get to study much maths and physics at school, so this level of conceptual explanation of these important concepts is fantastic for me. shashank Jain shashank Jain 2 years ago Sean this is really so good. Don't have enough words for your selfless contribution in tough times. Kudos Barton Cobert Barton Cobert 2 years ago Loved it. Please do more! James Lai James Lai 2 years ago (edited) Thank you Prof Carroll. Please don’t underestimate economists’ ability to hypothesize spherical cows. One of the most abstract theorems in Economics is Arrow’s Impossibility Theorem on voting systems. Vile Live Evil Vile Live Evil 2 years ago This was excellent (up to the point near the end where it was implied that there is more than one electron). Sandip Chitale Sandip Chitale 2 years ago (edited) Hi Sean, thanks for starting for this series and going to the heart of key concepts which generally not taught in the class. For example, why the idea of conservation of momentum is a paradigm shifting idea. I have a question about the Higgs field. Sometimes I have heard that Higgs field is like a molasses or viscous fluid which drags on the particles to give them mass. I can understand this to some extent when one tries to move a particle at rest, the viscosity will resist it hence the inertia. But molasses or viscous fluid will not let a particle to move at constant speed. It will slow it down. That is why I do not like molasses analogy. Instead I like the photon-box analogy for mass. What are your thoughts on this. I try to insist on use of correct analogies with non-physics educated people because it gives wrong impressions if the wrong analogy is used. Thoughts? Surendran Mk Surendran Mk 1 year ago Respected sir,can you explain where and how the kinetic energy of momentum is stored in side the material structure? The Memes of Destruction The Memes of Destruction 8 months ago And I’ve come full circle back here. The Universe is balance. Thank you again Professor! Grey Skelton Grey Skelton 2 years ago Great video! Thanks for taking the time to make and share 1 Anders Feder Anders Feder 2 years ago Always so to the point. Love it. Michael Toulch Michael Toulch 2 years ago (edited) Your explanations and attitude remind me of Feynmans videos- such as when he discusses why ice is slippery and why grandma (I think it was grandma) fell on it. Like him you could explain these great concepts to a high school dropout or an advanced scholar. Incredible stuff Dr Carroll - looking forward to the next round. 1 Warren and kids Warren and kids 1 year ago (edited) It’s some 20 years ago I learned Newtonian mechanics and conservative of momentum. Physics still fascinates me despite I have left the field for more than 10 years by now. Thanks for the series. I wish this existed when I started out in my physics training. Maybe I will show this to my children one day. My eldest is 7. Tuff Movies Tuff Movies 2 years ago enjoyed it alot, thank you would be great to hear more about free lunch theory in depth later in the series Canopus Canopus 1 year ago Thank You Sean! Wonderful explanation of principle of conservation of momentum. You gainsaid the momentum-concept in Aristotlallean physics and Newtonian physics. You talked about how systematic understanding of conservation of momentum leads to gain new understanding of the stuffs of cosmos in different perspective. Conservation of momentum is at the heart of cosmos which opens new reality, new problems and new frontiers. I got to know about Laplace's demons which is wonderful in the sense that it gives the knowledge of cosmic-mechanism as a whole. The last part of video is something I liked much because you talked about how physics works. You said, physicists compute Physics in very idealized arena and then add it to the real words, and it works more or less in same way as worked in idealized situation. This way of doing Physics is totally contrary to the way empiricist do Physics, for example Aristotle. pspicer777 pspicer777 2 years ago Outstanding!! Keep 'em coming. Thanks. 2 robert ford robert ford 2 years ago Nice lecture. Thanks. On the very last part regarding the meeting between Aristotle and Ibn Sina, another fairly specific advantage of the conserved-momentum/friction point of view would be that Aristotle would no longer have had to rely on his hopeless air-currents theory of arrows. Instead he could have just said that air just doesn’t generate much friction, which would be easy to show empirically. I like to think that Aristotle, who was a genius, would have leapt at this insight! MoreChazImages MoreChazImages 2 years ago Great start, you kept it interesting - just like your books - and a spherical cow bonus, wow! 20 Greg K Greg K 1 year ago Thanks very much for this series. Got to keep the neurons firing in the face of the monotony of the pandemic. 2 False 2 False 2 years ago Here’s a question: How does conservation of momentum hold in the context of quantum mechanics? 7 William Baker William Baker 2 years ago That was so worthwhile. Lovely. Thanks Sean. ADITYA RAJ ADITYA RAJ 2 years ago Beautiful lecture!👌 Ralph Ulrich Ralph Ulrich 2 years ago Sean Caroll, you are a great great teacher! Abstracting from reality was done early by mathematicians and architects: There is no pyramid or any circled building which in reality is the perfect geometrical form. There is no 1+1=2 in reality either, is it? Slartibartfast Slartibartfast 2 years ago I reckon you could write a book from these talks. You are so good at explaining these concepts that I think if it was in book form you could reach a wider audience. DeRozan Colored Glasses DeRozan Colored Glasses 2 years ago Love it! Thanks Sean! Manvendra Somvanshi Manvendra Somvanshi 2 years ago (edited) I think you should have mentioned symmetries and how they are connected to conservation laws (Noether's theorem). I personally think that Noether's theorem is one of the most beautiful things that exist in physics. I know that historically it came very late, but still I it should have been mentioned. 2 Thomas Larsen Thomas Larsen 1 year ago Dude, I am 62 years old... wish back in the day I had you (if I could go back in time and you stayed the same young age your are now) as a professor. You rock! Make things understandable to most. Love the Quantum info too!! Please do more. - Tom from Skokie, IL Genci Gorani Genci Gorani 2 years ago Hi Sean, thanx so much for sharing with us your insight on these ideas. In what is the Noether's theorem important in understanding the conservation ? Kieran Garland Kieran Garland 2 years ago Great idea for a series. Thanks for sharing. Irene Hernandez Irene Hernandez 2 years ago I want to thank you for the positive information about not giving up. I am a student of Dr Jatila van der Veen. I love her and had a great time in Astro 101. I like how I said "survive and move forward," "know learn and understand." It was helpful top hear you amd will watch some of your other pod casts. Thank you Shadab Sarvar Shadab Sarvar 2 years ago Awesome content, which app/ software / device are you using to write/ draw? Onur Yıldız Onur Yıldız 2 years ago These are so efficient, keep going to share please 👍👌 Dean Batha Dean Batha 2 years ago Thanks for these videos, Sean. I really enjoy them. But honestly, a cylindrical cow is a closer approximation to an actual cow. masih rezaee masih rezaee 1 year ago Thank you so much Sean for your great Idea. Thelonious2Monk Thelonious2Monk 2 years ago The idea of the spherical cow and its implications (as you have explained) should be explained in the first lecture in every middle and high school. In my experience students do not see the connection between the simplified physics they learn in class and the real physics they experience on a daily basis. This makes it hard for them to really appreciate the importance of the subject of physics to their life. Thanks for talking about it. The Biggest Ideas in the Universe | Q&A 1 - Conservation 96,907 viewsMar 29, 2020 Sean Carroll 154K subscribers Errata: at 7:23 I say "equilateral" triangle when I really just meant "right" triangle. (Also isosceles.) The Biggest Ideas in the Universe is a series of videos where I talk informally about some of the fundamental concepts that help us understand our natural world. Exceedingly casual, not overly polished, and meant for absolutely everybody. This is the first Q&A video, following the idea "Conservation" discussed here: https://www.youtube.com/watch?v=AeNSM... My web page: http://www.preposterousuniverse.com/ My YouTube channel: https://www.youtube.com/c/seancarroll Mindscape podcast: http://www.preposterousuniverse.com/p... The Biggest Ideas playlist: https://www.youtube.com/watch?v=HI09k... Blog posts for the series: http://www.preposterousuniverse.com/b... Background image: https://www.jpl.nasa.gov/missions/voy... #science #physics #ideas #universe #learning #cosmology #philosophy #math 213 Comments rongmaw lin Add a comment... Al S Al S 2 years ago One of my biggest joys while being quarantined here in a hot zone part of California is watching Professor Caroll's "The Biggest Ideas in the Universe". Thank you for sharing your knowledge with the rest of us. 73 Paps Aebus Paps Aebus 2 years ago You are such a great Teacher! I wish you could also do more advanced, full-fledged physics courses in this exact format, with mathematics and all that🙄 17 Rodrigo Serafim Rodrigo Serafim 2 years ago A positive effect of quarantine is that we now have a greater number of scientists doing their own podcasts and getting knowledge of complex topics into the general public. 18 Rob Alinder Rob Alinder 2 years ago (edited) OH MY GOD. I failed out of calculus three times in college. I only stopped because it was ruining my GPA. I wanted to be a physisist since I was 9 years old and tried and tried, but couldn't grok the maths! (I became a computer scientist instead LOL} The theory absorbs like a sponge but the nuts and bolts, I eventually accepted, were simply beyond me. Apparently my professors just were terrible! This video, and the barebones mathmatical theory involved, was an Eureka! moment for me, and youir explaination was just a tangent! Thank you, Sean Carroll! I feel foolish for not seeing the relationships I had at hand, and also a burning rsentment of what counts as an educational system in the United States for failing to actually educate me as me as a young, enthusiastic, student. 17 Mazin Jalili Mazin Jalili 2 years ago I’ve been a Patreon supporter of Mindscape since the beginning and a big fan of your work in general. You bet I’m going watch this series! 11 Lenn Lenn 2 years ago Oh my god that expression at 26:20 when Sean calls Emmy Noether “Emily” is just priceless :’) Thanks for not cutting (or more likely failing to cut) that out. 33 Sebastian Clarke Sebastian Clarke 2 years ago Wow what a series this is turning out to be! Its good to see you've already become very accustomed to presenting your doodles on the ipad, you seemed to be having a lot of fun with it. The whole presentation flowed super smoothly, well done and thank you so much!! I didn't know you were doing Q&A, hopefully I can offer you a few questions relevant to your upcoming topics. Thanks once again for such an amazing presentation, we're all truly humbled by your efforts as one of the worlds leading communicators of science. 5 Jarred Juett Jarred Juett 2 years ago I absolutely love these. Thanks, prof. Keep 'em coming! 3 MEF MEF 2 years ago I’d like to think the Many Worlds theory includes a universe in which I understand all this. 26 Spirinsola Spirinsola 2 years ago Suggestion: maybe a quiz at the end to see and apply what we've learned to help store it??? Like a challenge for us just learning. Thanks. 15 Atbinix Atbinix 2 years ago Thank you so much Sean for the time you put for explanation these fundamental concepts. Awesome timing as well while we are mostly at home. Sandra sandra Sandra sandra 2 years ago Thank you so much, from Italy on lockdown I appreciate the chance to learn such interesting things. I got to understand and love physics from you. 4 AMAN YADAV AMAN YADAV 2 years ago First, I was being lazy to tap in the video after watching this time line, but after tapping on it, It was like.... Why this video ended! Sir! I learnt a lot today and I am Very Very much Happy that I watched the video which clears all the basic doubts! Thanks! ♥️🙏Love from India! 5 Alfonso Tulli Alfonso Tulli 2 years ago Hello from Italy, professor, love what you’re doing with this series of videos! 2 Louise Westerbergh Louise Westerbergh 2 years ago You're an awesome company in days like these. Thank you so much for sharing your knowledge to a wider audience! Regards from Louise, Sweden. 3 The Underdog The Underdog 2 years ago Thank you Prof. Carroll! This series are much appreciated for people like me that don't have the means to go to a university and learn from the best. I have a question. What about Hawking radiation, wouldn't that violate conservation of energy in some way? 3 Xavier Gamer Xavier Gamer 2 years ago I’m loving these. Please keep it up. Thank you. 4 Soul DFS Soul DFS 2 years ago (edited) I like how you answered the Galileo, Newton, Ibn Sina question. Specifically the history Galileo experienced in Italy 🇮🇹! Great work! 2 CloudJits CloudJits 2 years ago Your stuff is amazing dude i love listening and getting my mind melted 😂🙏 keep it up! 2 Kostas Panagiotakis Kostas Panagiotakis 2 years ago Good morning Professor Carroll, Thank you so much for publishing such amazing content, in time like these it's great to see physics being divulged in such a simple cohesive and yet exciting way! Let me just begin by saying that I am a huge fan of yours. From your books to your podcasts and talks I have been following your work for quite some time now. I am currently trying to contact you because I just ended my BS Eng from case western reserve university in Engineering Physics and I have to say I am a bit lost on what path I should take next. I have a deep passion for physics, more in particular I like to question reality. A question I would like to answer is whether or not there is a unit of space time and if the Planck length truly is the ultimate unit of space time. Do you think that philosophy of physics might be a good path to answer such questions? Or do you think theoretical physics would be more appropriate? I know experimentally we don’t have a way to currently prove this, as we would need a particle accelerator immensely large to try and study the physics at such scales. I hope to hear from you soon Professor, Best wishes, and I look forward to more of your content in the Biggest Ideas in the Universe! 2 Narasimha Sithure A Narasimha Sithure A 2 years ago (edited) To a motivated learner , these videoes are of great help 👏 3 David Jeremy David Jeremy 1 year ago First question almost made me pass out I was laughing so hard. I would watch and hour of Sean reading usernames with a straight face. PRICELESSLY FUNNY!! Fox indabush Fox indabush 1 year ago (edited) 35:11 This is such a good explanation. Thanks for this. So this is also an explanation of not only e=mc2 but E = h · c / λ the difference always made me scratch my head because photons don't have mass from what little I understand and therefore could never really grasp how e=mc2 could be applied to them. So this energy then is turned into in some subtle way "vacuum energy" as you say - how is this explained in quantum field theory? Vacuum energy is just the neutral state of some discrete space/time field and somehow photons by losing all their energy or more accurately -> frequency & they become "flat" and disperse throughout the entire known universe all at once contributing to a greater sum of vacuum energy? lol. I think I'm stretching my brain too far but I greatly appreciate the videos, I'm really trying to educate myself recently - I have a long way to go!! (at least 23 episode :P ) sk8mysterion sk8mysterion 1 year ago I'm so glad that I've discovered this series, thank you! :) 1 Stephen Peterson Stephen Peterson 2 years ago I've just finished Feynman's six 1964 Messenger Lectures at Cornell, so this series is a great way to reinforce these ideas. 7 Gede Gabriel Gede Gabriel 1 year ago Thanks for this series. I am enjoying it a lot ! Roger Thornton Roger Thornton 1 year ago I just watched your first video, and loved listening to your understanding and explanations. you did make one comment in the q&a where you said that the photons energy will not be conserved as it is stretched through the expansion of the universe. You said that the energy goes down as the wavelength stretches, which is true, except that the actual energy in the photon does not change. if the energy in the photon changed the photon could not be moving at the speed of light. As it is moving at the speed of light the photon experiences no time. From the point that it left Galaxy X 13 billion years ago the photon has experienced no time, and no change, until it reaches our detectors here on Earth. But as we are moving away from it now at near the speed of light, because of the expansion of space, the energy seems to be lower as it is red shifted, but it is only our relative movement that makes that light seemed lower energy. If we were moving towards that same light source, it would seem much higher energy to our precepton. I don't know enough about this to know that I'm right, I am assuming that I have to be wrong at how I perceive this, otherwise everyone else is looking at this the wrong way. Thank you thank you thank you again for putting the time in to these lectures. I have watched many of them and decided I needed to start at the beginning if I really want to understand these big ideas. 1 Jelica Grčar Jelica Grčar 2 years ago Great idea ti share with us your knowledge and excelent teaching abilities during this selfquaranteen time. I enjoy it very much Sauce With Lyrics Sauce With Lyrics 2 years ago I've followed the podcast since the beginning. I'm not smart enough to understand 100% of the stuff that comes out of your mouth but I'm still enamoured by the physics. You make me second guess the thoughts in my head that tell me my lack of math and science means I shouldn't or can't learn more. You broaden my understanding, thank you. Bechu Pandit Bechu Pandit 2 years ago Keep em coming. Love your lectures NaR00W NaR00W 2 years ago I don't know what it is, but I get way less out of these videos than I do from Sean explaining things, or discussing them, with another person present. B Ntagkas B Ntagkas 2 years ago the barion thing reminds me of cellular automata, where you have to input 1 cell for the system to start 1 Chris Wesley Chris Wesley 1 year ago 31:30 Sean mentions how the expansion of space means the frequency/wavelengths of photons changes because of Doppler shift, and so the energy of the photon changes (E = hf and all that). That led me to think about relative motion THROUGH space, and how Doppler shift still ovvurs. Doesn't THAT mean that the energy of a photon is not only a property of that photon, but also of the relative motion betwen photon and observer? I know this is something of a digression but if anyone has the answer it may help many on this journey with Sean. Tristan Wibberley Tristan Wibberley 2 years ago (edited) A question on the conservation of momentum: Do two particles exist in the same reference frame at the same time - whatever "same time" can mean? ie, does a particle continue at a constant velocity because inertial frames are distinct and an interaction is required to destroy a particle in one frame and create some in other frames? matonted matonted 2 years ago (edited) 35:20 Would it be possible to have the decrease in photon energy and increase in vacuum energy to cancel each other out and keep the energy conserved? Kieran Garland Kieran Garland 2 years ago Thanks for this. Videos and Q&A a great combo 2 garlicgherkin garlicgherkin 2 years ago I have a few simple questions about different kinds of momentum. One, are planets in orbit around a star 'conserving momentum' by following the 'curvature of space' around the star, or is this is actually accelerated motion involving some expenditure of energy? I've heard references to orbits decaying but I don't know if this is due to some kind of friction (maybe deformations of the orbiting body) or just inherent in the nature of orbital motion. Two, is angular momentum, say a planet spinning on its axis, conserved, or is there also some inherent decay? Is there a clean relationship between angular momentum and linear momentum such that we don't need to distinguish them when talking about conservation of momentum? 1 MEF MEF 2 years ago I wish I had found this series in time to ask about the relationship of kinetic energy (1/2mv^2) and E=mc^2. Except for the “1/2” term the two fórmulas are identical. Since light is a velocity and since it’s the maximum velocity, is E=mc^2 not related to the kinetic energy of a mass moving at c? Years after my two basic college physics electives, I thought I had some breakthrough understanding the intuitiveness of E=mc^2 when I first realized the similarity of the two formulas. But, I had forgotten the 1/2 term. Sadly, I realized after college so I couldn’t just ask my teachers in class the next day. Ryan martin Ryan martin 2 years ago Keep it up! This is great. Darren Evans Darren Evans 2 years ago LOL at the cat chaos causing timeline jumps. Only Sean's cats could do this :) 8 MEF MEF 2 years ago (edited) 31:30 RE: the discussion of photons losing energy as space expands... Is it possible that the energy lost by the photon is somehow transferred to space itself (and this conserved)? If so, could this process be at least a contributor to the non-zero vacuum energy? Edit: “thus conserved” not “this conserved” Paul C. Paul C. 2 years ago Hi Prof Carroll, I just wondered if you have also been watching Brian Greene's "Your Daily Equation" ? I merely ask as a fan of both you and Prof. Greene. Thanks for this great new series BTW. Kumar Sivasithamparam (Knowledge Matters) Kumar Sivasithamparam (Knowledge Matters) 2 years ago WOW! Big Thanks. Awesome education for a nonscientist. iamtheiconoclast3 iamtheiconoclast3 1 year ago "Is the Universe a closed system? All the evidence we have says yes." Roger Penrose: "Hold my crumpet." 1 Wrong Time Weeder Wrong Time Weeder 5 months ago So happy your subscriber base is growing. Not a measure of how brilliant you are! hafeez moideen hafeez moideen 1 year ago I have heard your interviews in closer truth, as an athiest i would love to hear your videos and agree with the concepts Motorcycle Maniac Motorcycle Maniac 2 years ago Sean, in Hawking radiation, at the event horizon two virtual particles are produced as matter and antimatter. Is it true before they annihilate each other, they get pulled apart and one particle escapes into space and the other into the black hole. For black hole evaporation , does it matter which particle gets absorbed into the black hole ? Matter or antimatter ? Is it true it’s 50/50 which particle escapes ? 1 Jon Olsen Jon Olsen 2 years ago You should make it possible to pay for a membership to the channel where only members can see the q&a videos, or even make live streaming sessions to discuss the topics. SteelBlueVision SteelBlueVision 2 years ago At 7:23 , what you meant to say was that it is an isosceles right triangle, as in 45/45/90. It is certainly not equilateral (as Pythagoras showed)! 1 Bill Lyons Bill Lyons 2 years ago "I will not be naming everyone, just the ones with really funny usernames." 77 Terrence Zellers Terrence Zellers 1 year ago always wondered if it wouldn't save a lot of confusion among beginning physics students to write Einstein's infamy as dE/dm = c^2. Makes it rather obvious that the gain in mass in fission equates to excess energy which must manifest elsewhere in the system free air free air 2 years ago Good to see you in a pod cast Sean Franky Jones Franky Jones 2 years ago (edited) Don't cut your cats! I wish so much to see your cats at least once! (More seriously, I learn a lot with your videos and podcasts, thanks for everything!) Cooldrums777 Cooldrums777 2 years ago Excellent as usual. As much as I enjoyed the initial talk on conservation of P. This Q&A video was even MORE enjoyable. You do have a great gift for teaching. Every time you digress or expand on an explanation of some kind, its like you read my mind and answered the questions I was thinking about!!!!! I have read Feynmans Six easy and not so easy pieces (also read his biographies, etc). You absolutely deserve to be sitting at the great mans desk. Thank you for this video diversion in these crazy times. marko alling marko alling 2 years ago In the expanding universe do the energies gained by the cosmological constant and lost through redshift cancel each other out? If not is it possible that energy is conserved in the wave function of the universe (Hilbert space)? 1 Deepto Chatterjee Deepto Chatterjee 2 years ago I'm kinda confused, because in quantum mechanics the time derivative of the expectation value of an observable is proportional to the expectation value of the commutator of that observable with the Hamiltonian. So if the observable in question is the energy, then the time derivative of the expectation value of the energy is the expectation value of the commutator of the Hamiltonian with itself, which must be zero. So the expectation value of the energy is conserved. Is this not the conservation law of energy you were saying is not true? eye bee-sea eye bee-sea 2 years ago A conservation of the one (energy) but not the other (mass) would violate the energy-mass equivalence. In fact a hot cup of coffee has more mass than a cold cup of coffee, even though the total mass of any particle is equal in both cases. "Mass" is not bound to the particles alone, but to the closed system "cup of coffee". And for closed systems the conservation of mass is still valid. Philo-Sophy Philo-Sophy 2 years ago Thank you so much Sean! joshuad31 joshuad31 2 years ago Your sighing at the wave function really shows how much you are willing to respect your other colleagues in the field. Its almost like you are doing your best to acknowledge their POV although you've done so much to educate so many about a much more expansive POV that identifies the wave function as the fundamental underlying reality. Its kind of nice, it demonstrates the type of humanity you have. muffntheB muffntheB 2 years ago thank you for this, einstein was before media, hawking couldnt talk, the world really needs to hear whats going on inside your brain, this mite be the most important thing on the internet 2 Stephen Armiger Stephen Armiger 2 years ago (edited) I don't believe I am watching this. Finishing my second glass of wine and laughing hysterically. Fifty years since I graduated from college. The best I got in calculus was Cs and I pretty much forgot everything. Pretty uninspirational teacher. Took Khan Academy High School Calculus BC last year for awhile, so the waters are not so muddy. All that said, I am sort of following and sort of comprehending. Thank you. I bought your book, Something Deeply Hidden, and read the first few pages and I pulled out Laurence Krauss"s book, Fear of Physics and reread a bit today. He also mentions the cow/sphere analogy. Thanks for this. Chris Wesley Chris Wesley 1 year ago I've always struggled wiht the concept of expanding space. I know how to say the words but I don't understand the concept at all. How would we know space is expanding? Any physical ruler would exist within space and would expand along with the space. Does "speed" have meaning in expanding space? What about "distance"? It's so easy to say "expanding space" but I find it almost entirely unimaginable. Can anyone point me to somehwere helpful? nobody nobody 1 year ago Is there a system in which someone can learn how to learn? This to me is a big idea, because what is someone supposed to think about while watching these videos? How does someone prioritize an idea over another through all the chaos? William Benzley William Benzley 1 year ago If you spaced heavy objects throughout the known universe would it bend the universe enough to win? I guess I'm asking is the constant dependent on the amount of stuff? klsaknci klsaknci 2 years ago (edited) I hope you do an episode on mass, in particular the origin of mass as arising from the containment of massless particles (see PBS Spacetime “The True Nature of Matter and Mass”). I’d like to see this analogy extended into curved spacetimes so we can see how such a construction of massless particles experiences gravity and “feels heavy,” and if possible, how it could create curved spacetime/gravity. Jason Merrill Jason Merrill 2 years ago This is wonderful, I'm watching it again. 2 Ρгοηαtoг тεηdoη Ρгοηαtoг тεηdoη 1 year ago I think a lot of the misconceptions in theoretical physics and cosmic philosophy are a result of us trying to use digital math to quantify an analog cosmos. Every quantum interaction is just fields interacting, and they don't have numbers associated with them. What is required is a fundamental change in how we view math. Numbers and equations are not the path to precision. We need interferometric waveform math, and I think the path to that is quantum computing. We have to design a system we can't possibly understand (even the engineers and physicists) It's like trying to conceptualize a fourth special dimension. We can't possibly fathom a fourth axis at 90° simultaneously to all of the 3 dimensions we experience. Robert Lang Robert Lang 1 year ago carroll is arguably the best guide and explainer, when it comes to the mind-boggling , mind-stretching, contents of today's physics. He explains and even entertains, without oversimplifying and dumbing down the subject. Shoopaah Shoopaah 2 years ago This is gold. Needs more subs! Alex Focus Alex Focus 2 years ago I feel that your explanation of the neutron decay missed the point of the question. I think he was asking why is an antineutrino formed along with the p and e rather than a neutrino along with the p and e. 1 PavelSTL PavelSTL 2 years ago I feel like the answer to "Where did Momentum go?" confused things more than explained. And saying "just don't think about it that way" sounds more like a cop out than offering something in its place. Why not just say When things collide, they produce heat (just ask the dinosaurs, right?). But what is 'heat"? It's average kinetic energy/momentum of the particles. So all of that momentum of the entire moving ball went into the momentum of its individual particles, which are now moving around faster than before. Even photons that would radiate from the heat from the collision would have momentum. I feel like there's a reason why Sean didn't explain it that way, otherwise he would. Just wonder why? Tom Semo Tom Semo 2 years ago Great stuff. just what I need while at home.. 5 RedDoorYoga RedDoorYoga 2 years ago Take two rocks separated by some distance at time t=0. The universe expands until time t'=1, and now the distance between them is greater. The gravitational potential energy between those rocks should be greater now due to the increased separation. Shouldn't the same apply to galaxies? What am I missing? Wafikiri Wafikiri 1 year ago (edited) Where could we find an antiparticle for every particle in our universe? Just considering that time were going both directions simultaneously, every neutron in our universe's time direction would be its corresponding antineutron in the reverse time direction. Every proton, its antiproton. And so on. Total baryonic number in both time directions: 0. Total leptonic number in both time directions: 0. A nice symmetry, two universes in one (the antiuniverse would however decrease entropy in its own time direction.... but "past" the big bang instant, and I mean "past in the reverse time direction," it would increase entropy as it goes longer and longer past that instant, whereas it would be our universe's particles that would decrease entropy before the big bang in our time direction. Not sure if this all makes sense. . . . Could time really be both directions at once? Semantics are not really helping in such a situation, "at once" meaning "at every one instant" in this case. Alfred Maldonado Alfred Maldonado 2 years ago Good morning! If energy decays due to expansion, is there a relationship b/w dark energy & the vacuum energy? 1 whip8 whip8 2 years ago Excellent. Thank you. 2 moto theroad moto theroad 2 years ago More study needs to be on slit experiment. Quantum Physics is blowing by fundamental questions. They are ignoring that a massless photon will refract with matter as it crosses the slit of the experiment. This refraction is no different then light going thru glass. This surface tension that is alive with electrons will cause different wavelengths as photons bounce off electrons and be remitted connecting up at certain visible frequencies and other unseen frequencies. This is much different than the wave theory which doesn’t add up and the whole observer and entangle meant and wave interference is is more unlikely than photons being affected by surface it is passing and the slit experiment should be done at various thickness and at offsets etc..... So much to be done on the wave side. This what should be called a surface experiment instead of a slit experiment in conclusion is much more consistent with electro magnetic theory, Feynman diagrams and gravity! It is way more unifying than the unknowns of wave theory. Bailey Bartley Bailey Bartley 2 years ago If mass can turn into energy,, can we add energy to an object and have it gain and keep mass ? Descartesdom77 Descartesdom77 2 years ago I'm glad you talked about Baryogenesis and some less common conservation concepts, I honestly thought that you would skip it (like most physics explanation videos do). I'd rather you risk losing some of the more new people than just assuming that your whole audience can't understand. I like the concept of hanging some slightly difficult concepts out there in the hopes that it will inspire people to look deeper and understand those concept. Rafaella Zanchet Rafaella Zanchet 1 year ago We know as a fact that the universe is expanding , which affects the space . And if space time is one thing in itself it should be affecting time too, right ? If that is true how does that happen ? And can we perceive this effect here on Earth ? Kimberly Johnson Pemberton Kimberly Johnson Pemberton 4 months ago 🙈🙉 thank you for this free education, The intellects are the true rock stars! Randy James Randy James 2 years ago (edited) Does particle physics distinguish between a closed system and an isolated system? shagster1970 shagster1970 2 years ago Thanks for answering my question! John Weir John Weir 1 year ago I feel like if aliens were here, this is how they'd try and help us monkeys. Thank you Sean. John Kelley Brown John Kelley Brown 2 years ago What gadget are you using to write on? I'm tired of cluttering my desk with ideas and drawings, then taking pictures of them for future use so I can toss the paper. Nathaniel Carlson Nathaniel Carlson 4 months ago (edited) Trying to wrap my head around what happens when multiple worlds branch after an "observation" is made and how energy is conserved: - Energy = x in the pre-observed world in which a particle is actually a wave - An observation is made and the wave collapses into a particle; this now-entangled and branched world has energy = y1 < x - For simplicity, say there are 3 total "entanglements" possible -> are 3 branching worlds thus simultaneously created? If N possibilities -> are there always instantaneously N branched worlds? - For N branched worlds each with energy y (sub z) [where z is integers from 1 to N, and y1 may or may not equal y2 (etc...)], is it true that the summation of y1 + y2 + y3 ... +yN = x ??? Nick Nick 1 year ago Rest energy (mc2) does not seem to depend on material.... How do get all the rest energy out of a 1kg block of iron? Large molecules like uranium and small ones like hydrogen, sure but splitting or fusing iron doesn't give out energy. 1 calwz calwz 2 years ago Is time invariance violated in general relativity? (since energy is not conserved there) Adam Lane Adam Lane 2 years ago Fantastic , Thanks Sean Upendar Rao Gunda Upendar Rao Gunda 1 year ago Learning much stuff....Thank you.... Jakub Midera Jakub Midera 2 years ago Question about black holes If from our perspective anything aproaching the event horizon of a BH slows down in time how can we see a BH grow. And how can we see two BHs merge. The only thing we "should" see is seeing those object freeze in time as they aproach the event horizon. Dr. Mo Dr. Mo 2 years ago Well deserved flex of the spherical cow award 😄 Matt Black Matt Black 2 years ago The background behind you suggests you're taking the social distancing very seriously. 270 Peter Kovacs Peter Kovacs 2 years ago great !!!! thanks Sean!!!!! Pierre Houston Pierre Houston 2 years ago Sean, did I hear you say "cow particles" at 16:15? Are those the spherical cows you were talking about? :^) Chris Chris 2 years ago (edited) I love your cat anecdotes. Kareem Fawell Kareem Fawell 1 year ago Around the 20 minute mark, he discusses whether or not Galileo might have known about Ibn Sina or at least that Ibn Sina said that without effects like those from air resistance, an object would continue moving. I learned that Galileo used ramps so that he could more accurately time rolling balls by slowing them down. I now wonder if he also knew that he was minimizing the effect of air resistance. If he did, that might indicate at least knowing what Ibn Sina thought. I also wonder if Galileo had any guesses about if and how air resistance varies with speed. Iain Mackenzie 2 years ago (edited) For the attention of GCSE students, (17:30) Kinetic energy is a scalar. This is why we can "just add