General Relativity Lecture 1

(September 24, 2012) Leonard Susskind gives a broad introduction to general relativity, touching upon the equivalence principle.

This series is the fourth installment of a six-quarter series that explore the foundations of modern physics. In this quarter, Leonard Susskind focuses on Einstein's General Theory of Relativity.

Stanford University:

Stanford Continuing Studies Program:

Stanford University Channel on YouTube:

[tibees]

"I haven't been in a rocket ship but I have been in an elevator" I like how he uses the example that we can all imagine and understand. A great teacher 👏

[DonaldEFlood]

It's fantastic that one of the leading universities in the World, Stanford, would, at their own time & expense, provide to the general public, for free, the very best lectures that are available on topics such as this. Thank you Professor Susskind and thank you Stanford University!

[lucasbuvinic]

0:00 Intro
2:06 Original intuition : Gravitational forces = accelerated reference frame (-> tidal forces)
18:09 Curvilinear gravity (intro to coordinate transformations): Connection between gravity and curvilinear transformations of the coordinates of spacetime
24:02 Example of the elevator: equivalence principle applied to light
29:54 Intuitive notions on gravitational fields: you can't apply a coordinate transformation such that the tidal forces are eliminated (since gravity =/= accelerated frame of reference)
34:11 Fake gravitational field (created due to a certain nonlinear coordinate transformation) or a real gravitational field (tidal forces=real gravitational field)
43:58 The task: to find a coordinate transformation such that the tidal forces are eliminated
49:00 The mathematics that are involved in GR: Studying the geometry of spacetime (notion given to us by special relativity).
53:12 Riemannian Geometry
55:34 Curvilienar coordinates (and generalized distance)
1:06:22 The question of Riemannian geometry: Flat or not flat?
1:08:07 What does it mean for space to be flat?
1:08:47 Relation to the original problem of eliminating tidal forces
1:17:09 Coodinate transformations (intro to tensor analysis)
1:20:50 The notion of a contravariant vector (introduced from the perspective of the classic differential)
1:23:24 Definition a contravariant vector and how it's components transform under a coordinate transformation.
1:27:36 Einstein notation
1:28:57 The notion of a covariant vector (introduced from the perspective of the gradient of a function)
(note the connection between a basis (direction) and the partial derivative along an axis)
1:35:17 Definition a covariant vector and how it's components transform under a coordinate transformation.
Note: this whole introduction to coordinate transforms is nicely explained here but it's recommendable (and considering that most of us had to deal with linear algebra before getting to tensor analysis) that you'd watch eigenchris' Tensors for Beginners series
1:35:20 Central notion to tensor analysis: Tensors are defined by the way that they transform.
1:39:26 Generalization of this covariant and contravariant transformations (for rank 2 tensor with 2 covariant components or 2 contravariant components)
1:47:48 Transformation of the metric (unfinished) -> the metric is a tensor

[AsMyTiGeR]

I wonder how Proffessor Susskind manages to balance his time between lecturing and being a hitman for Walter White.

[RalphDratman]

What a great teacher. He seems like an ordinary guy, and he often gets mixed up on details, but when he gets to the heart of the matter, he is just wonderful. Thank you so much, Prof. Susskind. This is so helpful.

[JohnnyYenn]

It is such a privilege to be able to have access to these :0

[mrhphysics]

This is great. Serves multiple uses. For people who want to learn and for people who can't sleep but are conditioned to sleep through lectures. I fit both categories so it makes for a nice sleep aid and hopefully I will learn coordinate transformations in my dreams

[qbtc]

I found that the best way to learn from these lectures is to watch them twice. This is because it is always easier to review something vs learning it for the first time. Also, you always miss something the first time around if you are processing what Susskind is saying. You should review or learn Calculus 1, 2, 3 and some basic linear algebra and differential equations. Watch all of his Classical Mechanics and Special Relativity lectures before this as well. I reviewed Calculus 3 from Youtube's Professor Leonard and that turned out to be a great review of all of Calculus 1, 2, 3 since he teaches and reviews at the same. He is the best professor I have seen.

[marcoguariglia]

I don't understand a single mathematical passage but I watch these videos to measure the distance between me and these geniuses. great professor susskind

[andreamannoni]

I've done Physics and then moved to business, it's just wonderful to have available these lectures that bring me back to my twenties. Great initiative by one of the leading universities in the world

[theindianchannelmotivation]

he is just amazing he is the one who played an important role in developing string theory. He won the black hole war against hawking . he is awesome

[loooongneck]

How could 1.2k people dislike this. You are being presented some of the highest knowledge of our world by an accomplished expert for free within the comfort of your home. People 100 years ago would have been grateful as hell for resources like this

[aSeaofTroubles]

Einstein was so brilliant! I mean who can IMAGINE this?

Amazing lecture from Dr. Leonard Susskind.

[raffaelehuang]

The secret is that coffee. Coffee is the key to understand General Relativity. 

[NPCvsNPC]

If I am ever able to do something with my life, a lot of credit has to go to these free Stanford classes

[davethinkingsystems]

This shows that someone who truly understands his topic can express it in a way others can understand.

[jpatrick]

The only word I understand in this video is elevator.

[AnonYmous-skkp]

These are "continuing education" courses and we are very lucky to have them. You can tell by the questions from the audience that nearly all of them are in completely over their heads. He is doing a great service by presenting these topics at this level, considering the level at which he actually understands them.

[tclaughridge]

My mind was blown at 28:50. The dots connected in my head and I understood the nature of the relationship between gravity, time, and acceleration. Truly amazing.

[sundarrajn]

susskind is doing a great favor to humanity by posting these lectures...thanks a lot..