The Biggest Ideas in the Universe | 16. Gravity

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 Idea #16, "Gravity." By which we mean Einstein's theory of General Relativity, according to which gravity is the curvature of spacetime. Since we've already learned about spacetime and about curvature (geometry), this one is a breeze.
My web page: www.preposterousuniverse.com/
My KZbin channel: / seancarroll
Mindscape podcast: www.preposterousuniverse.com/p...
The Biggest Ideas playlist: • The Biggest Ideas in t...
Blog posts for the series: www.preposterousuniverse.com/b...
Background image: Astronaut Bruce McCandless floating in space, NASA. www.nasa.gov/astronautprofile...
#science #physics #ideas #universe #learning #cosmology #philosophy #gravity #generalrelativity #einstein #spacetime

[@seancarroll]

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.

[@Janson-Aims]

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?

[@hhaavvvvii]

@@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.

[@varunachar87]

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.

[@varunachar87]

However, this entire series of videos has been extremely valuable, and I thank you for it and for all your other work!

[@QuantumNeutrinos]

Thank you very much for taking the time to share those videos with us. Really appreciated.

[@drazicmilosovic1065]

THIS is what KZbin is for. Educational - accessible - inspirational. Thank you!

[@HawthorneHillNaturePreserve]

And cute animal videos. Let’s be honest.

[@drazicmilosovic1065]

@@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.

[@syzygy808]

Highly agree.

[@reallyryan_]

Nah

[@jmike2039]

Yes

[@rhondagoodloe3275]

Thanks again for your willingness to put so much time and effort into this project!

[@sirilandgren]

Such a treat for us knowledge-hungry internet beings!

[@merc9nine]

You know he gets paid for this. Its like thanking someone for writing a book.

[@1boobtube]

@@merc9nine he has written books lol... and thanks for those as well.

[@tantiwahopak101]

@@merc9nine what a dumb statement. Why are you even here 😂

[@1boobtube]

@@flatearthfisherman7153 keep fishing...

[@kobev3li385]

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.

[@bennybundi9671]

Kobe the goat but Sean carol is god

[@NuclearCraftMod]

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.

[@tessellatedagain]

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!

[@SlyFoxFo]

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.

[@mysticwine]

Nye is a joke!

[@gafrancisco]

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

[@fromaggiovagiola9128]

@@gafrancisco Tyson is a charlatan.

[@luminositymusicbrianpricka6357]

Yeah.

[@alangarland8571]

@@fromaggiovagiola9128 Neh, he is black though.

[@sanjchiro]

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

[@schelsullivan]

One of the only things I allowed to notify me on my phone. Glad to be here early and often

[@johnh9363]

@@muskyelondragon ... And in such a comprehensible way. Not that I follow all of it of course.

[@VeganSemihCyprus33]

This must be know by all, the rest is details: kzbin.info/www/bejne/e33NmIepbKd5eZY

[@tungstikum]

I find myself gravitating towards Sean's videos!

[@Ivan_chepaykin]

Well put)

[@ypey1]

Badum tschhhhh

[@elck3]

*cymbal* hit

[@johnnybgoodeish]

I wonder if there is an equation for this? At what rate? Is there some kind of force impelling you towards this? :)

[@thewaytruthandlife]

as long as you dont fall into his black hole !

[@joeking4206]

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.

[@ralphclark]

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.

[@imaseeker100]

There are many brilliant minds among us but few are as articulate and engaging as Mr. Carroll.

[@Andrew_from_Oz_Vinyl_Landscape]

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

[@robmack4986]

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.

[@calvingrondahl1011]

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.

[@tinman652]

Sean Carroll the man

[@EarlWallaceNYC]

Once again: I've gotten great insights into a topic I've know for years. Thanks

[@FamKielczewski]

Same

[@MrJackjr69]

@@FamKielczewskiyes me too, since childhood

[@88_TROUBLE_88]

👈🏻 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

[@dnavas7719]

OMG I've loved every single one but this is the ONE I was waiting for!!! Thanks a lot Dr. Carroll ❤❤❤

[@mathewmoore8375]

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!

[@davidsardarov252]

I hope it is like you said: "100 years from now your series will still be on KZbin..." It is golden and for everyone to know! Thank you.

[@Dr10Jeeps]

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).

[@mrloop1530]

As a non-university psychology professor, I also love these sessions with Sean Carroll.

[@randommcranderson5155]

as a cat, meow

[@Neme112]

@@randommcranderson5155 meow 🥺

[@Rocky-Boy]

Why was it necessary to mention your occupation here?

[@Dr10Jeeps]

@@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.

[@donthurtmyfeelingsplz]

Holy crap this is amazing. Finally that next level of understanding I can't get from audiobooks and other KZbin videos. A true lecture

[@bennybundi9671]

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

[@Cygnus__X1]

Sean, never ever stop a video short because you think it's too long! absolutely amazing work here keep it up!

[@mattlitton1255]

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

[@OkieDokieSmokie]

Wish I'd known Sean had a youtube channel sooner.

[@themajestysnowbird]

Here here

[@davidgriffith598]

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!

[@JohnHoranzy]

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.

[@jordanweir7187]

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 :)

[@jhoughjr1]

to teach is to learn again.

[@hero227]

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.

[@tanvach]

Absolutely incredible series. The amount of detail is spot on to understand these concepts and not bogged down by details. Thank you!

[@vincentbutton5926]

This video is the icing on the top of this series... and there are more videos to come. Just brilliant!

[@001firebrand]

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 ❤

[@Wightkitesurfer]

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...

[@yorkwestenhaver8680]

lol

[@at0mly]

This might be my favorite video series ever.

[@trumanhw]

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.

[@paulc96]

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 !!

[@ewur3.gaming905]

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.

[@kill_em_dafoe]

Thanks so much for this! As a layman these are concepts I’ve only ever understood along the broadest possible lines, and you’ve really helped to open a door for me. Thanks Sean!

[@jakelittleton7316]

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.

[@xXcod4evrXx]

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

[@rage9715]

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.

[@HawthorneHillNaturePreserve]

Just the opportunity to listen to you lecture is beyond amazing! Your delivery, humor and passion, make listening to you very easy. Thank you 🙏

[@quinntalley1681]

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.

[@christianhujer346]

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!

[@vicsummers9431]

These videos are absolute gems. Thanks Sean!

[@rbettsx]

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.

[@AtmosMr]

".... 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.

[@yoso585]

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.

[@LeOnIdAs162]

Thank you so much Dr. Sean for sharing this amazing lecture with us ! Cheers from Brasil !

[@boyanfg]

Thank you for your passion to teach this to the public. This is a great series!

[@kagannasuhbeyoglu]

Great series continues. Thanks a lot Prof.Carroll

[@johnjoseph9823]

My favourite theory. Thanks Sean for the in-depth explanation

[@peteclark9]

Best description of why gravity is the curvature of spacetime I have ever heard

[@mesokosmos2212]

This is what I've been waiting for in these lectures. And worth of waiting it was! I liked the idea of linking integrales and special relativity with GR.

[@Bradgilliswhammyman]

This is pretty neat Mr Carroll, been a long long time fan of your ideas and discussions on physics. This is the first one where I get to be involved in trying to understand the math behind the ideas.

[@lindsayforbes7370]

Just brilliant, thanks, your knowledge and enthusiasm is breathtaking

[@LE0NSKA]

that intro and thumbnail is so 90s I love it

[@virtualmoyda7221]

Gravity and reverse gravity are truely fascinating subjects. Also thank you for doing such a good job at relaying this stuff to the masses.

[@papsaebus8606]

Can’t wait for the Cosmology & Black Hole lectures🔥🔥

[@rage9715]

That'll be 5 hours long at best 😅😅

[@ManWhoUsesComputer]

Such a gift. Thank you SC!

[@cortezcabret9408]

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.

[@JFT241]

I read your book The Big picture! Along with other great courses you've done. Had no idea you were here on KZbin. 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.

[@leahcimrelbats]

Thanks for making these videos. Good work!

[@Aymn-zl4kl]

You're awesome dude, love the biggest ideas in the universe series 👍

[@muttleycrew]

These videos are so much fun, thanks Sean!

[@w6wdh]

24:15 Loved the joke about the topologist drinking coffee, but he’s not sure if its in a coffee mug or a doughnut.

[@sirilandgren]

This means that in the cop combo of coffee + donut, one is superfluous?!

[@becomepostal]

This is a fantastic video. I’ve never seen so many ideas *clearly* explained in so short time.

[@lukea5067]

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!

[@johntamulonis4626]

I always feel very lucky to be listening to Sean Carroll, I think he is one of the great scientists of our day.

[@mikespilligan1490]

Seans voice is like melted swiss chocolate flowing over a caramel base.

[@subhanusaxena7199]

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

[@MohaymenPK]

Again Mr.Sean, thank you fo much for making these.

[@VeganSemihCyprus33]

This is the most important knowledge to be known, the rest is details: kzbin.info/www/bejne/e33NmIepbKd5eZY

[@lucavalentino]

Thanks for this fantastic and enjoyable lectures!!!

[@rapxparkour]

Thanks for sharing sean! Great content. Cheers from Chile

[@globaldigitaldirectsubsidi4493]

Finally someone gives you a rough idea about the mathematics! Big thanks, Sean!

[@stephenbryant7873]

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.

[@lashram32]

Thank you so much for putting this out there for the world for free. You are a nerdy hero.

[@MikkelHojbak]

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. 🤣

[@johnh9363]

... Splat!

[@jcf20010]

Where is the connection field that predicts the graviton? This is my favorite video so far. I actually understood 95% of it this time. 😀

[@godinhos7797]

You need to solve the schrödinger full equation for join gravity and quantium EFFECTS, at my website i make this samuelgodinhophysics.science.blog/

[@godinhos7797]

Graviton is the "noise" on space and this noise said how quantium effects works and this solve much things but full knowledge is impossible...

[@rosspetersen4434]

Man, you really know how to attract an audience!

[@TranscendentPhoenix]

I see what you did there...

[@carstenbjrneboe5774]

Thats gravity in action

[@voges1001]

Massive audience *

[@y5mgisi]

I love listening to Sean Carroll.

[@henryj.8528]

This is the best one so far. Very clear, step-by-step. It did "payoff" btw. Thanks for doing this series.

[@EarlWallaceNYC]

Phrase of The Week: "I promise you that I hope it pays off" (@ 38:35)

[@rage9715]

We need this on a shirt or something.

[@navidazadi4280]

Thank you very much dear Prof. Caroll

[@Joaocruz30]

Love your class! Thanks and greetings from Portugal

[@Ryo-sd9rx]

This guy is something special, people pay (owe) thousands of dollars for this information and we get it free

[@davidgarofalosteachingcorner]

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.

[@vinaygr28]

Thank you so much Dr Carroll!

[@cyruskalali8222]

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..

[@dajandroid]

Your presentation has finally melded the physics with the supporting math for me. Thank you!

[@DonaldLL825]

Ive learned more in this one video than I have in any/many class(es) at the university attempting to explain the same material

[@dougg1075]

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:)

[@systematicapproachtoPhysics]

Wonderful efforts sir Sean Carroll 💖

[@NEWDAWNrealizingself]

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 !!

[@rickharold7884]

Beautiful! Thanks for the videos!

[@redaabakhti768]

Inspiring videos thanks a lot for your time

[@OmnipotentO]

Wow! I could listen to this guy's science talks all day

[@ForrestNeal]

Please make more videos educating us Sean!

[@eklim2034]

Wow, what a timeless piece of lecture

[@disagol]

I was waiting for this! Thanks sean

[@TheGreatAlan75]

Your voice and style, for me, are like ASMR.....I feel very comfortable listening to you, Dr. Carroll...