General Relativity Lecture 8

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  • čas přidán 10. 09. 2024
  • (November 12, 2012) Leonard Susskind develops the coordinate transformations used to create Penrose diagrams, and then uses them to describe the physics of black hole creation.
    This series is the fourth installment of a six-quarter series that explore the foundations of modern physics. In this quarter Susskind focuses on Einstein's General Theory of Relativity.
    Originally presented in the Stanford Continuing Studies Program.
    Stanford University:
    www.stanford.edu/
    Stanford Continuing Studies Program:
    continuingstud...
    Stanford University Channel on CZcams:
    / stanford

Komentáře • 65

  • @erwinmarschall2465
    @erwinmarschall2465 Před 11 lety +5

    1:14:45 I think he means 2 different horizons: (1) Schwarzschild horizon, which is fixed by the shell's mass (2) the "doomed" horizon of Alice.
    If the mass-shell crosses the Schwarzschild horizon, this point becomes the center of the Kruskal diamond and the left triangle should be turned up so that it's inside the BH (because of "interchange" between time and space) and Alice is doomed as usual.

  • @Boepyne
    @Boepyne Před 11 lety +9

    I struggled to understand the chapter on conformal diagrams in Penrose's book 'Cycles of Time' but this made it completely clear - great stuff!

    • @stoobe
      @stoobe Před 5 lety +1

      I came to this video for the same reason!

  • @phildurre9492
    @phildurre9492 Před 8 lety +5

    58:10 thats really amazing, you can be behind the horizon, and yet thing you are safe and in flat space.

  • @TheVivek199
    @TheVivek199 Před 5 lety +17

    1:07:02
    "Alice is the one who always goes in the black hole."
    (laughter)
    "It's a convention. I didn't invent it."

    • @simoncrase5360
      @simoncrase5360 Před 4 lety +5

      According to this article, www.realclearscience.com/articles/2018/12/29/a_brief_history_of_black_holes_110845.html, in 1933 Abbe Georges Lemaître became the first person to drop Alice into a black hole.

    • @aloknathsingh4647
      @aloknathsingh4647 Před 4 lety +1

      He had to say it keeping in mind the feminists

    • @meowwwww6350
      @meowwwww6350 Před 4 lety

      Hi bro Tamila?

  • @paulm1241
    @paulm1241 Před 3 lety +3

    Passing through a wormhole is like going to negative r in polar coordinates: it only works if you are a mathematician.

  • @bushje
    @bushje Před rokem +1

    another astonishingly good lecture!! thank you!!

  • @iosuegea9607
    @iosuegea9607 Před 4 lety +1

    An amazing lecture. Congratulations to the teacher as well as to the students for their questions.

  • @TheVivek199
    @TheVivek199 Před 5 lety +13

    56:08 "Excuse me while I consult with Newton"

  • @jenniferlaflora3293
    @jenniferlaflora3293 Před 5 měsíci +1

    Susskind detention. Receipt 0:13 mean your parents talk to you 0:20

  • @iiiiii-w8h
    @iiiiii-w8h Před 4 lety +7

    Glad the camera man zoomed in on the whiteboard. I wanted to see that one bacteria there.

  • @realcygnus
    @realcygnus Před 11 lety +1

    be careful....F youtube = F google....where would we be without both/either ?
    this is pure mind candy !...all of Lennys vids are priceless but this one really takes the cake

  • @cmilkau
    @cmilkau Před 3 lety +1

    Feels as if the horizon is like a shadow cast by the singularity

  • @Waranle
    @Waranle Před 11 lety +2

    thank you

  • @dgilbourd
    @dgilbourd Před 6 lety +2

    If Alice is a black hole who thinks she is standing still. Bob is a different black hole who
    also thinks he is standing still. Charlie is sitting far away and also thinks he is standing still. They are all spinning relative to each other. Do Alice and Bob both think they have spherical horizons? Or can they deduce from their shape what their angular momentum is relative to privileged Charlie?

  • @stoobe
    @stoobe Před 5 lety +1

    Seems like the black hole formed form the in-falling light sphere (aka Kugelblitz Black Hole) has information sent faster than the speed of light. At the moment the light reaches its Schwarzschild radius this video says it forms a black hole horizon. But how does the space at one end of the horizon know that enough light energy has reached the horizon on the other parts? I see two fraught possibilities:
    1) the light becomes so concentrated at the horizon that locally it creates the necessary space-time warping to look like a black hole horizon. (but how do you avoid a black hole horizon at the same place if you only send half a sphere?)
    2) the horizon only forms once the light all reaches the center and then gravity/space-time waves travel out form the center. (but you cant send information to an increasing radius from inside a black hole)

  • @davidpaganin3361
    @davidpaganin3361 Před 5 lety +2

    I am extremely grateful for these lectures -- a million thanks.

  • @nabildoingsTuff-o1w
    @nabildoingsTuff-o1w Před 17 dny

    isnt this a little simplifyed ?

  • @jenniferlaflora3293
    @jenniferlaflora3293 Před 5 měsíci +1

    I said ? You said to him b ? 0:44

  • @petergreen5337
    @petergreen5337 Před 10 měsíci

    Thank you very much ❤

  • @xinzeng-iq7zv
    @xinzeng-iq7zv Před 4 měsíci

    persistence may pay off

  • @pierfrancescorosini6183

    Why does he say that quadrant 3 and 4 have no physical meaning?

  • @johnnychinstrap
    @johnnychinstrap Před 2 měsíci +1

    How bad did Alice break Lewis Carrol's heart. lol

  • @jenniferlaflora3293
    @jenniferlaflora3293 Před 5 měsíci

    No there is out door ed 1:05:49

  • @gpcrawford8353
    @gpcrawford8353 Před 4 lety

    BTW Italian mathematicians added insights to Bernhardt Riemann’s work believe they added them to give a mathematic for calculating stress and strain in spherical structures . This was in relation to an engineering problem. Hence you get a stress energy tensor involved. Einstein praised them no end. Einstein was in touch with Levi-Civita using Italian which he had gained from a 6-9 months stay in Milan at a relatives company. Still don’t understand the maths but love these lectures .

  • @epaulk1969
    @epaulk1969 Před 5 lety

    14:14 The "repulsion" of the light ray is centrifugal force? Is he mistaken? Can someone help me out with this one?

    • @user-dl5xm6su3n
      @user-dl5xm6su3n Před 4 lety +1

      It's a fictitious force, not a real one. He means that it looks as the light ray is being repelled from the origin.

    • @sriramvecham4369
      @sriramvecham4369 Před 4 lety

      it is correct, the thing is in light reference frame (which of course we should not say) it sees that it comes closer to a point and suddenly it starts going away from it and the only explanation light has is there is some force which did not allow it to go more closer, whereas in reality light was just not pointed towards the point, it is just reference frame thing.

  • @user-vw8xh5ko5d
    @user-vw8xh5ko5d Před 2 dny

    Lee Anthony Walker Gary Lewis Betty

  • @sender1496
    @sender1496 Před 8 lety +18

    Same people asking the same questions over and over again, which all take 5 seconds of thinking to figure out.

  • @audreymciver3087
    @audreymciver3087 Před 4 lety

    So now I am really confused and think i should go back to college to learn everything i need to know to save everyone.

  • @BYMYSYD
    @BYMYSYD Před 5 lety +1

    Susskind never says "somewhere" he always says "somewheres"

    • @Urdatorn
      @Urdatorn Před 4 lety +1

      I’d like to hear Susskind sing ”Somewheres over the rainbow”

    • @DanielFBest
      @DanielFBest Před rokem

      @@Urdatorn

  • @Biednymaniek
    @Biednymaniek Před 4 lety

    We on an Expression poin right

  • @NeedsEvidence
    @NeedsEvidence Před 6 lety +7

    The camera man is a disaster, sometimes zooms in too much when Susskind points at things outside the field of vision.

    • @drderpphd
      @drderpphd Před 6 lety

      NeedsEvidence I noticed that, too; probably someone filling in

  • @jenniferlaflora3293
    @jenniferlaflora3293 Před 5 měsíci

    David, talk exactly we’ve lived with you please please yours across the feet move the leaves your doors don’t look too close to close close close the police don’t leave the police don’t close the 1:26

  • @AkamiChannel
    @AkamiChannel Před 3 lety

    Why are these questions so dumb? Look at the diagram, people.

  • @jenniferlaflora3293
    @jenniferlaflora3293 Před 5 měsíci +1

    Oh you are a male school 😅

  • @Biednymaniek
    @Biednymaniek Před 4 lety +1

    😂

  • @googelplussucksys5889
    @googelplussucksys5889 Před 9 lety +1

    I wish he would explain this in less than 80 minutes...

    • @exodaniel
      @exodaniel Před 8 lety +16

      Play the video at 2x speed

  • @NeedsEvidence
    @NeedsEvidence Před 6 lety +1

    Where are my apple comments?

    • @NeedsEvidence
      @NeedsEvidence Před 6 lety +1

      56:40 DISGUSTING EATING SOUNDS!

    • @NeedsEvidence
      @NeedsEvidence Před 6 lety +2

      1:02:58 Fuck you Lenny for being so disrespectful to your students. Take a 5 min break if you want to eat, but please don't talk while eating your stupid apple and having a fucking mic at your throat. Oh yeah, you think you doing it for free changes this assessment? I think not.

    • @NeedsEvidence
      @NeedsEvidence Před 6 lety +1

      And hey, censor, I can copy & paste for eternity!

    • @kemokidding
      @kemokidding Před 6 lety +2

      You have misophonia. Most people don't.

  • @Denosophem
    @Denosophem Před rokem

    Sometimes you chewing makes me irritated lmfao but hey it takes lots of brain power to teach and learn this so: I can’t complain

  • @bilyanatomova7677
    @bilyanatomova7677 Před 6 lety +1

    ok lecture, but the chewing sound is unbearable

  • @goldenscarecrow397
    @goldenscarecrow397 Před 4 lety

    Why does he talk so slowly? I get that it’s a hard subject and we sure need time to understand but he repeats each thing about three times

  • @5hu6hy4nk
    @5hu6hy4nk Před 6 lety +2

    This guy looks like Mike from Breaking Bad