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.

#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.

[X-boomer]

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.

[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!

[rhondagoodloe]

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

[kobevli]

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.

[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

[joeking]

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.

[larryboulware]

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.

[drazicmilosovic]

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

[imaseeker]

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

[robmack]

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.

[DrJeeps]

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).

[EarlWallaceNYC]

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

[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

[vintagerealityvr]

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

[yararitaa]

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

[bennybundi]

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

[dnavas]

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

[calvingrondahl]

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.