Couple of errata: Around 48:00, the first entry in the components of the metric should be -1, not +1. And around 1:02:40, I said the Riemann tensor has 128 entries, when of course it's 4x4x4x4 = 256.
Please forgive my ignorance, but could 4th dimension physics explain gravity as the impellar effect of an astral body's 4th dimensional representation, presumably with the "suction power" proportionate to it's mass, spin and movement through a 4 dimensional manifold space?
@@Janson-Aims They've measured the effect of gravity enough through gravitational waves to know that it has to transmit in 3-D space for energy conservation to make sense.
Another couple of errata: At 0:58:52, for r squared you put the 2 as a subscript instead of as a superscript. At 1:17:07, you define theta as the latitude instead of as the colatitude, but then the metric tensor component for dphi^2 conflicts with this definition.
I am astounded. Delivering an overview of GR mathematics in under two hours that is comprehensible to someone who only studied maths to high school level forty years ago? It's not the first time I've attempted to grasp it but it's the first time I came anywhere near succeeding without having to just take every step as "given". The first lecture of every college physics course should be just like this. Then spend all the rest going over the fine details. Dr Carroll you're a hell of an educator.
Thank you, Professor for this gift. I left physics in 1971 after qualifying for my PHD. I became an internist. For all of those years I have been reading popular books on these subjects. These videos put me back in the classroom. You are an amazing teacher.
How you showed the differences and ultimately the relationship between gravity and geodesics to other gauge fields, I thought the explanation was so clear I couldn't help but shed a tear when marveling these concepts. Words cannot express how much this series is appreciated Dr. Carroll, thank you so very much again for all your insights and all the time you devote to this series. Which truly has to be the most wonderful series on youtube today.
One thing I don't understand though is this: the connection in the case of a gauge field is the field itself, while in the case of the gravitational field, the connection is made up of derivatives of the metric, not the metric itself.
@@HawthorneHillNaturePreserve Good catch - I stand corrected. As my profile photo demonstrates; I’m a crazy cat person (the picture is my “son” - Giuseppe. Video compilations about erratic feline misbehaviour are a regular feature contained in our domestic rituals.
Thank you Sean Carroll! Your series here on YT, the Royal Institution, etc… You conversations on the Mindscape Podcast… is a gift to humanity that I thoroughly enjoy since I found this. Please never stop doing this and consider me a humble fan from Austria. This is all gold and writing history!
Absolutely brilliant Sean. I am 61 and have a 2:1 degree ( English) in Mechanical Engineering. I studied differentiation and lots of other stuff but this is the best lectures(s) that I have ever seen.
I've studied this for years with minimal success, and never come across such a clear explanation, thanks so much, I love when someone explains something with the intention of actually teaching the material instead of just looking smart :)
As a university psychology professor, I love these sessions with Dr. Carroll. He is such an engaging person (to say nothing about being brilliant as well).
@@Rocky-Boy I think I was trying to convey the fact that although I am not a physicist and have no training in the field I am enthralled with quantum mechanics and cosmology and Dr. Carroll speaks on these topics in a way that laypeople like me can understand. Obviously that was not the interpretation of my message.
Mr. Carroll, thank you so much for taking the time to explain EFE. Everywhere I looked, everyone would give examples for application, and when you have not been ever properly explained where symbols and letters derived from, or why those symbols do what they do, the language of the math in my head was indecipherable. Now I know what is being applied and derived from these equations. Thank you so much.
As an introductory physics student I’ve been interested in this stuff all of my life and have spent a lot of time understanding it but this was by far the most clear, intuitive, explaining I’ve heard, with the history and mathematical concepts interlaced gave me such a deeper understanding of what I already thought I understood! Will be binge watching these videos now
I fell asleep, watching this, and proceeded to have a dream in which Sean Carroll came to my house and wouldn't stop talking😂 I would try to ask him a question but he would just give me this like mean look and keep talking and I couldn't understand why he was being so rude. Lololol
Really great add on to this video is Sean's Mindscape solo episode on Einstein's equation. The absolute best explanatory marriage to help the non physicist understand GR. Thank you so much Dr. for this!
Dear Sean , I have read your blog, preposterous universe, but stumbled on these videos yesterday, fantastic work for generations, like the famous Feynman Lecture series
I graduated in May with a degree in physics and was taught special relativity in modern physics and intro to cosmology. However, I never had a proper course in GR since it wasn't offered at my school, so I decided to find a textbook on the subject and attempt to learn as much as possible about it. I bought your textbook a few weeks ago and have been reading through it and I'm trying to absorb as much as possible. I'm soooooo so happy that you have a video series on this and it helps to follow along with you while going through the text. Thank you so much for these videos!
Of COURSE I stayed until the end, Dr. Carroll. So very generous of you to share. Having been unable to afford college this's truly a wonderful 'gift' to have a _favored author / teacher_ teach courses.
Relaxing presentation, I can rewatch this over and over and learn something new every time. I am a retired editorial cartoonist and your drawing is just fine.
👈🏻 Yeah, card carrying member of Mensa since age 5 here too.. Kindergarten teacher hated me and imagine how every other teacher I had to humor since then must've felt in my presence.. Must have been mortifying for those individuals who were unlucky enough to have me assigned |to them for an entire year.. But they lucked out because I never once completed an entire school year without having been expelled F c č c c¥or the of the year until next grade year started and I did it all over again and again until I graduated with a GED
Dear Prof. Carroll, thank you so much for that. I have known Einstein's Equation of GR for years, but this is the first time that I have actually UNDERSTOOD what all the terms & symbols really mean. That was the most comprehensive & complete explanation that I have ever been able to follow.Thanks again from a lifelong fan. You should stand for President of the USA !!
This video stands out for me as having the right blend of simplicity, complexity and flow to optimize my understanding of the current model of gravity which has always been very mysterious to me. Sincere gratitude Sean, thank you.
It is always nice to listen to someone far more educated in the various sciences than I. At a certain point it becomes as a foreign language to me. But that’s what I like. I like it that you know what your talking about and I trust that you have me covered.
Sean, just wanted to say you are so eloquent and well-spoken, that you deliver complex messages in a way that everyone can easily understand. Thanks for the videos, and look forward to all the content you make in the future.
In freshman and sophomore physics we learn about Poisson equations for both electric and gravitational fields. But general relativity makes the Poisson equation for gravity the result of a weak field limit. It might be interesting to discuss why the gravitational field behaves similarly to the electric field in that regime and why it must differ more generally.
Saw this posted to reddit, great timing since I just started reading your space time and geometry book. I went and checked out some of the other videos in the series and they are great! Really love this, I think you're one of the best physics communicators out there right now
Even after having a master degree in Botany and the research experience of four years in PLANT TISSUE CULTURE I could comprehend the Mathematical formalism of the GENERAL RELATIVITY you just have described in a lucid way . thanks sir !!
Fell asleep listening to this, ended up dreaming I was back in class, and one of my friends was incredibly eruditely and confidently talking about gravity....and I was half listening thinking, shit, he seems to really know his stuff...
Dr. Caroll is cool dude! First met him in the 2nd episode of "Order and Disorder" hosted by prof. Jim Al-Khalili. Best wishes both of them by the way ❤
Sean, thank you so much for creating these. I am someone who missed the boat on physics. I had no encouragement to pursue these topics until later in life. While I'm likely never going get back to school for these subjects, I appreciate you breaking down these big ideas in a very consumable way. Thanks for helping us all think big thoughts.
Thanks a lot Sean. You are great. As a chemical engineer by eduaction, , it has been several decades since I dealt with equations. It is helpful to show us the equations, despite the fear of speakers and scientists, to write any equations, since it scares away the audience. Your sketches and diagrams are very helpful. This is a university lecture and I have to see it several times to digest it all. Thanks again..
Dr. Caroll made me understand linear algebra on a deeper level. IF he accepts students in 2022, when I might retire from work... I'll ask a visa for two semesters under his tutelage. Just for the fun of learning from the BEST teacher in pĥysics. Dr. Caroll must receive the Nobel prize in Vulgarization.
I just finished my master's degree for which I took an introductory course into general relativity: this captures all the important aspects... I'll be watching each lecture! Thanks!
I don't mind the longer videos, I see it like a lecture, not a PowerPoint. I think it allows you to be more thorough even though I know you like to keep them shorter
This video is so great. And so hard. I didn’t watch any previous ones, just started with this one so I’m not sure if I should watch them in order. But maaaan.... I love this video because for the first time I understand how talentedly-intelligent of a person you have to be to truly understand this in mathematical terms.
This is the first satisfying video that I came across about this topic. Every other video only explains parts of the physics, but never the maths behind it. I love this video. I will watch it a few times. Thank you @Sean Carroll for making this! I'm learning so much from this!
Dr. Carroll: Of the "Big Ideas" series, gravity is the most fun. I'm just a bohunk guy from Georgia, but your presentation skills make me feel like an actual smart person. I think it's the respect you have for your viewers. Plus, gravity is my favorite physics topic. My second favorite topic is the particle-wave duality issue. I'll call you when I have it sorted out.
I'm sure you didn't mean to say that Newton's equation for the force of gravity didn't contain any time elements, when of course force is in units of Newtons--which is kg*m/s^2 and very much contains time. Force is the time derivative of momentum, as Newton knew very well. Newton did think that a force would effect masses instantaneously regardless of distance, but that does not have to do with the equation for the force of gravity.
This is the most views video in The Biggest Ideas in the Universe Series/Course. At the time I am writing this comment this video has around 500k views. For comparison, the second most viewed video in this video series is about Quantum Mechanics which is about 250k views. So this is twice as popular as any other video in this series. I was expecting Quantum Mechanics to go just as high (if not higher) but was surprised to see the difference.
There is a big difference between understanding the base principles, and being able to work problems, and having such an intuitive big picture view that it flows seamlessly without really even thinking about it. It’s true that only a few people really had a flawless intuitive grasp of what relativity implied. I learned this from a well respected professor who had many contributions to heat flow and he talked about entropy the same way.
I was listening to this while working on my lawn when these attractive math treatments of gravity caught my attention because gravity has been mysterious to me but I didn't see the same or similar videos on YT to enlighen me. Surely I'll watch it from the beginning to see whether it can convince me of the 4th force of the universe.
Man I fell asleep with this going and I had a dream Sean was my guest speaker at a party at an old folks home for the wealthy. I was getting treatments for cancer at the party and Sean was feeling sorry for me following me around. Crazy:)
Dr. Carroll, great lecture, but as I watched one thing sprang to mind .. why would changes in the geometry of space be limited to the speed of light? Einstein tells us that gravity is a distortion of space - time so if that distortion changes (the geometry of space changes) why would that change be limited to C?
This makes all the other lectures I've watched on this subject so much more accessible! Fantastic! Undergraduate lecture series should recommend this overview for some folks, like me, before getting down to the number-grinding.
Finally someone gives you a rough idea about the mathematics! Big thanks, Sean!
4 роки тому+1
27:26: "So you are accelerating right now unless you just jumped off a building or something like that. So that concludes the truly fun part of our video..." Beautiful transition there Sean. 🤣
Thank you so much Dr. Carrol for these amazing videos! your desire to educate people has always been inspiring and its so wonderful you continue to offer these world class courses for free. Keep being a rockstar of science bro
Really enjoyed this and many others in your Biggest Ideas series, and Mindscape program. Thanks a bunch for the walk down memory lane. Hoping you have a wonderful 2021.
That was brilliant, and the kicker is right at the very end. This is all so close to the real understanding which is that the energy of the broad field os space is not uniform. There is a minimum field energy, but the presence of matter increases the field energy inversely proportional to the distance from the primary body of energy, the Quarks. The boundary zone of a quark is effectively an “event horizon” inside which matter energy operates at above light speed and the kicker at the end explains why this is possible. It is this fact that that energy inside a quark operates at above light speed is why that energy is contained by the field. The energy cannot escape the boundary as the field which restricts energy to the speed of light becomes impermeable to matter energy. The energy that the quark imparts to the field is the origin of Gravity. The Gravity effect is field energy difference between the Field Energy of Deep Space relative to the the Field Energy in the presence of Matter. The more and denser the matter the greater the Field Energy and the Greater the experienced “Force due to Gravity”. This would suggest that within the event horizon of a black hole matter energy is completely unrestrained and all information inside the event horizon is lost. As to the box arguments at the beginning, where you realise that the field energy level is a product of the relative field energy at any region of space, then you realise that from within a box you can map the space around you, and even determine speed and direction relative to a body of matter. To do this you would need an extremely sensitive field energy meter which you move in a uniform spherical pattern and the field energy measurements would reflect the proximity and amount of matter in the vicinity of the box. Dark matter is expected to not be actual matter, but “phantom matter” where regions of space have a higher background energy value. Gravitational effect is determined relative ‘intensity” of the field energy where matter flows from low field energy towards high field energy, or where photons deflect towards the highest field energy density (bending of light). Zones of high field energy are created when Neutron Stars collapse to a black hole and the intense field energy around them becomes dissociated from the matter that created it as Quark boundary breaks down and becomes an event horizon. In that moment of collapse when matter energy is released and energy goes in all directions, the energy that goes inwards becomes trapped in the forming event horizon and the energy that goes in the opposite direction escapes as a massive energy release. The field energy that constrained the Neutron quarks that were released as pure energy elevate the field energy of the region and become “phantom matter”, or Dark Matter. All physics has to do to finally unify Gravity into a slightly modified Standard Model is to take a harder look at the Nature of the Higgs Field at the Plank Scale, and the mechanism by which the “field” restrains free energy to the speed of light.
I read your book The Big picture! Along with other great courses you've done. Had no idea you were here on UA-cam. Maybe you weren't here until I looked but either way you've got yourself another subscriber. Thank you for sharing your knowledge with all of us, really appreciated.
To arrive at the correct/predictable theory of physical reality, we have to resort to principles, such as the 'equivalence principle', 'symmetry', 'invariance] many other similar principles. We also have to check for in variance, such as gauge, etc. Maldacena shows how 'duality' is ubiquitous, ADS/CFT (even Platonic volumes have their dual), Dirac shows the dual of electron/positron pairs, Hartnoll shows many forms of duality playing in a BH,providing deep insight. Once we ensure/derive the dual of a concept, we can predict more and the theory becomes transparent.
I understood very little of this video 28 minutes in, but the overall ideas are interesting and engagingly discussed that I'll be saving this for the full watch later
Dear Professor Carroll: So I’m out on my boat water skiing. For some darn reason I love impressing my friends with my knowledge of physics (I am a psychologist not a physicist). Maybe it’s the natural environment....who knows! So I explained to my friend that if you are falling out of a plane it only appears as though you are falling but in reality you are not falling because according to General Relativity the earth is accelerating up to you! My friend stopped putting his ski on and went silent for a moment in thought and then said: “how could that be true because the earth is round so if 2 people jumped out of an airplane on opposite ends of the earth how could earth be accelerating up to both persons at the same moment. He stopped me in my tracks while I fumbled with an answer ...which was beyond me...until I watched your video about gravity. Suddenly I was no longer the Einstein avocational expert since I could not respond intelligently to his skepticism despite my PhD in psychology! Thanks for your brilliance Hope you find this funny! All the best Ray Sent from my iPhone
How does the gravity of a black hole escape the black hole? Why doesn't the interior get cut off and the outside snap back to flat? Is it like flat spacetime has a pressure pushing it into the hole, or spacetime has a tension strong enough to pull it through the event horizon?
That's a very good question actually. Which is easily answered, in theory if gravity is nothing but an emergent, is proper terminology I think, property of the curvature of spacetime itself...? Which...pretty much matches what you said if I understand correctly. I should point out that I am not speaking out of personal experience.
Thank you, one of the best talks I have seen on this. Maybe you could have added one more consequence of the field equations as gravitational waves. A video deriving the wave equation from EFE would be awesome. Thank you
Couple of errata: Around 48:00, the first entry in the components of the metric should be -1, not +1. And around 1:02:40, I said the Riemann tensor has 128 entries, when of course it's 4x4x4x4 = 256.
Please forgive my ignorance, but could 4th dimension physics explain gravity as the impellar effect of an astral body's 4th dimensional representation, presumably with the "suction power" proportionate to it's mass, spin and movement through a 4 dimensional manifold space?
@@Janson-Aims They've measured the effect of gravity enough through gravitational waves to know that it has to transmit in 3-D space for energy conservation to make sense.
Another couple of errata:
At 0:58:52, for r squared you put the 2 as a subscript instead of as a superscript.
At 1:17:07, you define theta as the latitude instead of as the colatitude, but then the metric tensor component for dphi^2 conflicts with this definition.
However, this entire series of videos has been extremely valuable, and I thank you for it and for all your other work!
Thank you very much for taking the time to share those videos with us. Really appreciated.
I am astounded. Delivering an overview of GR mathematics in under two hours that is comprehensible to someone who only studied maths to high school level forty years ago? It's not the first time I've attempted to grasp it but it's the first time I came anywhere near succeeding without having to just take every step as "given".
The first lecture of every college physics course should be just like this.
Then spend all the rest going over the fine details.
Dr Carroll you're a hell of an educator.
Thank you, Professor for this gift. I left physics in 1971 after qualifying for my PHD. I became an internist. For all of those years I have been reading popular books on these subjects. These videos put me back in the classroom. You are an amazing teacher.
How you showed the differences and ultimately the relationship between gravity and geodesics to other gauge fields, I thought the explanation was so clear I couldn't help but shed a tear when marveling these concepts.
Words cannot express how much this series is appreciated Dr. Carroll, thank you so very much again for all your insights and all the time you devote to this series. Which truly has to be the most wonderful series on youtube today.
Kobe the goat but Sean carol is god
One thing I don't understand though is this: the connection in the case of a gauge field is the field itself, while in the case of the gravitational field, the connection is made up of derivatives of the metric, not the metric itself.
THIS is what UA-cam is for. Educational - accessible - inspirational. Thank you!
And cute animal videos. Let’s be honest.
@@HawthorneHillNaturePreserve Good catch - I stand corrected. As my profile photo demonstrates; I’m a crazy cat person (the picture is my “son” - Giuseppe. Video compilations about erratic feline misbehaviour are a regular feature contained in our domestic rituals.
Highly agree.
Nah
Yes
Thank you Sean Carroll! Your series here on YT, the Royal Institution, etc… You conversations on the Mindscape Podcast… is a gift to humanity that I thoroughly enjoy since I found this. Please never stop doing this and consider me a humble fan from Austria. This is all gold and writing history!
Thanks again for your willingness to put so much time and effort into this project!
Such a treat for us knowledge-hungry internet beings!
You know he gets paid for this. Its like thanking someone for writing a book.
@@merc9nine he has written books lol... and thanks for those as well.
@@merc9nine what a dumb statement. Why are you even here 😂
@@flatearthfisherman7153 keep fishing...
Absolutely brilliant Sean. I am 61 and have a 2:1 degree ( English) in Mechanical Engineering. I studied differentiation and lots of other stuff but this is the best lectures(s) that I have ever seen.
The Bob Ross of science
I hope it is like you said: "100 years from now your series will still be on UA-cam..." It is golden and for everyone to know! Thank you.
I love how Sean gets breathless and so excited, must have been a little like what Einstein would have felt at the time when the Eureka moment hit
There are many brilliant minds among us but few are as articulate and engaging as Mr. Carroll.
I've studied this for years with minimal success, and never come across such a clear explanation, thanks so much, I love when someone explains something with the intention of actually teaching the material instead of just looking smart :)
to teach is to learn again.
As a university psychology professor, I love these sessions with Dr. Carroll. He is such an engaging person (to say nothing about being brilliant as well).
As a non-university psychology professor, I also love these sessions with Sean Carroll.
as a cat, meow
@@randommcranderson5155 meow 🥺
Why was it necessary to mention your occupation here?
@@Rocky-Boy I think I was trying to convey the fact that although I am not a physicist and have no training in the field I am enthralled with quantum mechanics and cosmology and Dr. Carroll speaks on these topics in a way that laypeople like me can understand. Obviously that was not the interpretation of my message.
Mr. Carroll, thank you so much for taking the time to explain EFE. Everywhere I looked, everyone would give examples for application, and when you have not been ever properly explained where symbols and letters derived from, or why those symbols do what they do, the language of the math in my head was indecipherable. Now I know what is being applied and derived from these equations. Thank you so much.
One of the only things I allowed to notify me on my phone. Glad to be here early and often
@@muskyelondragon ... And in such a comprehensible way. Not that I follow all of it of course.
This must be know by all, the rest is details: ua-cam.com/video/ELjgTs7BFC4/v-deo.html
As an introductory physics student I’ve been interested in this stuff all of my life and have spent a lot of time understanding it but this was by far the most clear, intuitive, explaining I’ve heard, with the history and mathematical concepts interlaced gave me such a deeper understanding of what I already thought I understood! Will be binge watching these videos now
I fell asleep, watching this, and proceeded to have a dream in which Sean Carroll came to my house and wouldn't stop talking😂 I would try to ask him a question but he would just give me this like mean look and keep talking and I couldn't understand why he was being so rude. Lololol
😂😂😂 I have dreams about this while it's playing too.
Really great add on to this video is Sean's Mindscape solo episode on Einstein's equation. The absolute best explanatory marriage to help the non physicist understand GR. Thank you so much Dr. for this!
Holy crap this is amazing. Finally that next level of understanding I can't get from audiobooks and other UA-cam videos. A true lecture
Dear Sean , I have read your blog, preposterous universe, but stumbled on these videos yesterday, fantastic work for generations, like the famous Feynman Lecture series
I graduated in May with a degree in physics and was taught special relativity in modern physics and intro to cosmology. However, I never had a proper course in GR since it wasn't offered at my school, so I decided to find a textbook on the subject and attempt to learn as much as possible about it. I bought your textbook a few weeks ago and have been reading through it and I'm trying to absorb as much as possible. I'm soooooo so happy that you have a video series on this and it helps to follow along with you while going through the text. Thank you so much for these videos!
I find myself gravitating towards Sean's videos!
Well put)
Badum tschhhhh
*cymbal* hit
I wonder if there is an equation for this?
At what rate?
Is there some kind of force impelling you towards this? :)
as long as you dont fall into his black hole !
Of COURSE I stayed until the end, Dr. Carroll. So very generous of you to share.
Having been unable to afford college this's truly a wonderful 'gift' to have a _favored author / teacher_ teach courses.
Sean is so friendly and relaxing he could be the Bob Ross of Physics.
It is obvious he tries to teach from the perspective of the student.
Relaxing presentation, I can rewatch this over and over and learn something new every time. I am a retired editorial cartoonist and your drawing is just fine.
Sean Carroll the man
You make Tyson and Nye look like kindergarten teachers 🔥
Thanks for treating us as intellectuals. It's such a departure from the rest of social media.
Nye is a joke!
There's a difference ...this guy explains to the the little group of experts ... Tyson explains for the rest of us ...like you and me :D
@@gafrancisco Tyson is a charlatan.
Yeah.
@@fromaggiovagiola9128 Neh, he is black though.
Once again: I've gotten great insights into a topic I've know for years. Thanks
Same
@@FamKielczewskiyes me too, since childhood
👈🏻 Yeah, card carrying member of Mensa since age 5 here too..
Kindergarten teacher hated me and imagine how every other teacher I had to humor since then must've felt in my presence.. Must have been mortifying for those individuals who were unlucky enough to have me assigned |to them for an entire year.. But they lucked out because I never once completed an entire school year without having been expelled F c č c c¥or the of the year until next grade year started and I did it all over again and again until I graduated with a GED
Dear Prof. Carroll, thank you so much for that. I have known Einstein's Equation of GR for years, but this is the first time that I have actually UNDERSTOOD what all the terms & symbols really mean. That was the most comprehensive & complete explanation that I have ever been able to follow.Thanks again from a lifelong fan. You should stand for President of the USA !!
Sean, never ever stop a video short because you think it's too long! absolutely amazing work here keep it up!
This video stands out for me as having the right blend of simplicity, complexity and flow to optimize my understanding of the current model of gravity which has always been very mysterious to me. Sincere gratitude Sean, thank you.
He clearly enjoys teaching and is great at it
It is always nice to listen to someone far more educated in the various sciences than I. At a certain point it becomes as a foreign language to me. But that’s what I like. I like it that you know what your talking about and I trust that you have me covered.
Sean, just wanted to say you are so eloquent and well-spoken, that you deliver complex messages in a way that everyone can easily understand. Thanks for the videos, and look forward to all the content you make in the future.
".... And know you know what it is". Boom. Thank you Sean. Brilliant presentation. Just kept me in awe and wonder throughout. Einstein... What a mind.
In freshman and sophomore physics we learn about Poisson equations for both electric and gravitational fields. But general relativity makes the Poisson equation for gravity the result of a weak field limit. It might be interesting to discuss why the gravitational field behaves similarly to the electric field in that regime and why it must differ more generally.
OMG I've loved every single one but this is the ONE I was waiting for!!! Thanks a lot Dr. Carroll ❤❤❤
Saw this posted to reddit, great timing since I just started reading your space time and geometry book. I went and checked out some of the other videos in the series and they are great! Really love this, I think you're one of the best physics communicators out there right now
Even after having a master degree in Botany and the research experience of four years in PLANT TISSUE CULTURE I could comprehend the Mathematical formalism of the GENERAL RELATIVITY you just have described in a lucid way . thanks sir !!
Fell asleep listening to this, ended up dreaming I was back in class, and one of my friends was incredibly eruditely and confidently talking about gravity....and I was half listening thinking, shit, he seems to really know his stuff...
lol
Gravity and reverse gravity are truely fascinating subjects. Also thank you for doing such a good job at relaying this stuff to the masses.
Absolutely incredible series. The amount of detail is spot on to understand these concepts and not bogged down by details. Thank you!
This might be my favorite video series ever.
Dr. Caroll is cool dude! First met him in the 2nd episode of "Order and Disorder" hosted by prof. Jim Al-Khalili. Best wishes both of them by the way ❤
I always feel very lucky to be listening to Sean Carroll, I think he is one of the great scientists of our day.
Sean, thank you so much for creating these. I am someone who missed the boat on physics. I had no encouragement to pursue these topics until later in life. While I'm likely never going get back to school for these subjects, I appreciate you breaking down these big ideas in a very consumable way. Thanks for helping us all think big thoughts.
Thanks a lot Sean.
You are great.
As a chemical engineer by eduaction, , it has been several decades since I dealt with equations.
It is helpful to show us the equations, despite the fear of speakers and scientists, to write any equations, since it scares away the audience.
Your sketches and diagrams are very helpful.
This is a university lecture and I have to see it several times to digest it all.
Thanks again..
Dr. Caroll made me understand linear algebra on a deeper level. IF he accepts students in 2022, when I might retire from work... I'll ask a visa for two semesters under his tutelage. Just for the fun of learning from the BEST teacher in pĥysics. Dr. Caroll must receive the Nobel prize in Vulgarization.
I just finished my master's degree for which I took an introductory course into general relativity: this captures all the important aspects... I'll be watching each lecture! Thanks!
I don't mind the longer videos, I see it like a lecture, not a PowerPoint. I think it allows you to be more thorough even though I know you like to keep them shorter
I don't think you could fit gravity into a 10-20 minute video in-depth. It's great that he doesn't gloss over the topics.
This video is so great. And so hard. I didn’t watch any previous ones, just started with this one so I’m not sure if I should watch them in order. But maaaan.... I love this video because for the first time I understand how talentedly-intelligent of a person you have to be to truly understand this in mathematical terms.
This is the first satisfying video that I came across about this topic. Every other video only explains parts of the physics, but never the maths behind it. I love this video. I will watch it a few times. Thank you @Sean Carroll for making this! I'm learning so much from this!
Dr. Carroll: Of the "Big Ideas" series, gravity is the most fun. I'm just a bohunk guy from Georgia, but your presentation skills make me feel like an actual smart person. I think it's the respect you have for your viewers. Plus, gravity is my favorite physics topic. My second favorite topic is the particle-wave duality issue. I'll call you when I have it sorted out.
Best description of why gravity is the curvature of spacetime I have ever heard
Can’t wait for the Cosmology & Black Hole lectures🔥🔥
That'll be 5 hours long at best 😅😅
This is a fantastic video. I’ve never seen so many ideas *clearly* explained in so short time.
Wish I'd known Sean had a youtube channel sooner.
Here here
Your voice and style, for me, are like ASMR.....I feel very comfortable listening to you, Dr. Carroll...
Just the opportunity to listen to you lecture is beyond amazing! Your delivery, humor and passion, make listening to you very easy. Thank you 🙏
These videos are absolute gems. Thanks Sean!
I'm sure you didn't mean to say that Newton's equation for the force of gravity didn't contain any time elements, when of course force is in units of Newtons--which is kg*m/s^2 and very much contains time. Force is the time derivative of momentum, as Newton knew very well.
Newton did think that a force would effect masses instantaneously regardless of distance, but that does not have to do with the equation for the force of gravity.
This is the most views video in The Biggest Ideas in the Universe Series/Course.
At the time I am writing this comment this video has around 500k views.
For comparison, the second most viewed video in this video series is about Quantum Mechanics which is about 250k views. So this is twice as popular as any other video in this series.
I was expecting Quantum Mechanics to go just as high (if not higher) but was surprised to see the difference.
There is a big difference between understanding the base principles, and being able to work problems, and having such an intuitive big picture view that it flows seamlessly without really even thinking about it. It’s true that only a few people really had a flawless intuitive grasp of what relativity implied. I learned this from a well respected professor who had many contributions to heat flow and he talked about entropy the same way.
I was listening to this while working on my lawn when these attractive math treatments of gravity caught my attention because gravity has been mysterious to me but I didn't see the same or similar videos on YT to enlighen me. Surely I'll watch it from the beginning to see whether it can convince me of the 4th force of the universe.
Ive learned more in this one video than I have in any/many class(es) at the university attempting to explain the same material
Wow! I could listen to this guy's science talks all day
Man I fell asleep with this going and I had a dream Sean was my guest speaker at a party at an old folks home for the wealthy. I was getting treatments for cancer at the party and Sean was feeling sorry for me following me around. Crazy:)
Phrase of The Week: "I promise you that I hope it pays off" (@ 38:35)
We need this on a shirt or something.
Dr. Carroll, great lecture, but as I watched one thing sprang to mind .. why would changes in the geometry of space be limited to the speed of light? Einstein tells us that gravity is a distortion of space - time so if that distortion changes (the geometry of space changes) why would that change be limited to C?
Thank you for your passion to teach this to the public. This is a great series!
Thanks for making these videos. Good work!
This makes all the other lectures I've watched on this subject so much more accessible! Fantastic! Undergraduate lecture series should recommend this overview for some folks, like me, before getting down to the number-grinding.
I feel I can relax this week... something I've thought a lot about. Still, I'm prepared to learn something new, perhaps quite a significant something.
Your presentation has finally melded the physics with the supporting math for me. Thank you!
My favourite theory. Thanks Sean for the in-depth explanation
Finally someone gives you a rough idea about the mathematics! Big thanks, Sean!
27:26: "So you are accelerating right now unless you just jumped off a building or something like that. So that concludes the truly fun part of our video..."
Beautiful transition there Sean. 🤣
... Splat!
This guy is something special, people pay (owe) thousands of dollars for this information and we get it free
Wow, what a timeless piece of lecture
Where is the connection field that predicts the graviton?
This is my favorite video so far. I actually understood 95% of it this time. 😀
You need to solve the schrödinger full equation for join gravity and quantium EFFECTS, at my website i make this samuelgodinhophysics.science.blog/
Graviton is the "noise" on space and this noise said how quantium effects works and this solve much things but full knowledge is impossible...
Again Mr.Sean, thank you fo much for making these.
This is the most important knowledge to be known, the rest is details: ua-cam.com/video/ELjgTs7BFC4/v-deo.html
Thank you so much Dr. Carrol for these amazing videos! your desire to educate people has always been inspiring and its so wonderful you continue to offer these world class courses for free. Keep being a rockstar of science bro
Really enjoyed this and many others in your Biggest Ideas series, and Mindscape program. Thanks a bunch for the walk down memory lane. Hoping you have a wonderful 2021.
Seans voice is like melted swiss chocolate flowing over a caramel base.
Inspiring videos thanks a lot for your time
That was brilliant, and the kicker is right at the very end. This is all so close to the real understanding which is that the energy of the broad field os space is not uniform. There is a minimum field energy, but the presence of matter increases the field energy inversely proportional to the distance from the primary body of energy, the Quarks. The boundary zone of a quark is effectively an “event horizon” inside which matter energy operates at above light speed and the kicker at the end explains why this is possible. It is this fact that that energy inside a quark operates at above light speed is why that energy is contained by the field. The energy cannot escape the boundary as the field which restricts energy to the speed of light becomes impermeable to matter energy. The energy that the quark imparts to the field is the origin of Gravity. The Gravity effect is field energy difference between the Field Energy of Deep Space relative to the the Field Energy in the presence of Matter. The more and denser the matter the greater the Field Energy and the Greater the experienced “Force due to Gravity”.
This would suggest that within the event horizon of a black hole matter energy is completely unrestrained and all information inside the event horizon is lost.
As to the box arguments at the beginning, where you realise that the field energy level is a product of the relative field energy at any region of space, then you realise that from within a box you can map the space around you, and even determine speed and direction relative to a body of matter. To do this you would need an extremely sensitive field energy meter which you move in a uniform spherical pattern and the field energy measurements would reflect the proximity and amount of matter in the vicinity of the box.
Dark matter is expected to not be actual matter, but “phantom matter” where regions of space have a higher background energy value. Gravitational effect is determined relative ‘intensity” of the field energy where matter flows from low field energy towards high field energy, or where photons deflect towards the highest field energy density (bending of light). Zones of high field energy are created when Neutron Stars collapse to a black hole and the intense field energy around them becomes dissociated from the matter that created it as Quark boundary breaks down and becomes an event horizon. In that moment of collapse when matter energy is released and energy goes in all directions, the energy that goes inwards becomes trapped in the forming event horizon and the energy that goes in the opposite direction escapes as a massive energy release. The field energy that constrained the Neutron quarks that were released as pure energy elevate the field energy of the region and become “phantom matter”, or Dark Matter.
All physics has to do to finally unify Gravity into a slightly modified Standard Model is to take a harder look at the Nature of the Higgs Field at the Plank Scale, and the mechanism by which the “field” restrains free energy to the speed of light.
I read your book The Big picture! Along with other great courses you've done. Had no idea you were here on UA-cam. Maybe you weren't here until I looked but either way you've got yourself another subscriber. Thank you for sharing your knowledge with all of us, really appreciated.
To arrive at the correct/predictable theory of physical reality, we have to resort to principles, such as the 'equivalence principle', 'symmetry', 'invariance] many other similar principles. We also have to check for in variance, such as gauge, etc. Maldacena shows how 'duality' is ubiquitous, ADS/CFT (even Platonic volumes have their dual), Dirac shows the dual of electron/positron pairs, Hartnoll shows many forms of duality playing in a BH,providing deep insight. Once we ensure/derive the dual of a concept, we can predict more and the theory becomes transparent.
I understood very little of this video 28 minutes in, but the overall ideas are interesting and engagingly discussed that I'll be saving this for the full watch later
I love listening to Sean Carroll.
Dear Professor Carroll: So I’m out on my boat water skiing. For some darn reason I love impressing my friends with my knowledge of physics (I am a psychologist not a physicist). Maybe it’s the natural environment....who knows! So I explained to my friend that if you are falling out of a plane it only appears as though you are falling but in reality you are not falling because according to General Relativity the earth is accelerating up to you! My friend stopped putting his ski on and went silent for a moment in thought and then said: “how could that be true because the earth is round so if 2 people jumped out of an airplane on opposite ends of the earth how could earth be accelerating up to both persons at the same moment. He stopped me in my tracks while I fumbled with an answer ...which was beyond me...until I watched your video about gravity. Suddenly I was no longer the Einstein avocational expert since I could not respond intelligently to his skepticism despite my PhD in psychology!
Thanks for your brilliance Hope you find this funny!
All the best
Ray
Sent from my iPhone
Great mix of math, graphs, and analogies. Can help bridge those gaps.
Thank you very much dear Prof. Caroll
This is one my favorite, I keep watching it over again trying to remember it all lol
Great series continues.
Thanks a lot Prof.Carroll
You are doing a great job of describing the effects of and the measurement of gravity, but well short of explaining what gravity is
How does the gravity of a black hole escape the black hole? Why doesn't the interior get cut off and the outside snap back to flat? Is it like flat spacetime has a pressure pushing it into the hole, or spacetime has a tension strong enough to pull it through the event horizon?
That's a very good question actually.
Which is easily answered, in theory if gravity is nothing but an emergent, is proper terminology I think, property of the curvature of spacetime itself...? Which...pretty much matches what you said if I understand correctly.
I should point out that I am not speaking out of personal experience.
Man, you really know how to attract an audience!
I see what you did there...
Thats gravity in action
Massive audience *
Principle of Equivalence has always bothered me to but never saw the small region explanation before. Now I get it.
Thank you, one of the best talks I have seen on this. Maybe you could have added one more consequence of the field equations as gravitational waves. A video deriving the wave equation from EFE would be awesome. Thank you