Leonard Susskind | Lecture 2: Black Holes and the Holographic Principle
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- Опубликовано: 5 фев 2025
- Second of three Messenger lectures at Cornell University delivered by Leonard Susskind
Theoretical physicist Leonard Susskind delivered the second of his three Messenger Lectures on "The Birth of the Universe and the Origin of Laws of Physics," May 30, 2014. Susskind is the Felix Bloch Professor of Theoretical Physics at Stanford University, and Director of the Stanford Institute for Theoretical Physics.
It always amazes me how easy physics seems with prof. Leonard Susskind as he simplifies things
+Philippe durrer He is actually better hung over, He goes slower, explains his formulas better and eíncludes every step. He is also a lot less condescending to his students.
He is a good teacher
❤well said and well OBSERVED
Has a couple of beers before explaining black hole physics. Old school genius.
❤Thank you very much Professor and class.
At 36:00 says something that caught my attention ! a black hole reflect radiation that has lower wavelengths than radius of the blackhole.
He mentioned that in one version of the reality the horizon is emitting high energy photons. So is that are what is referred to as the "firewall"?
40:28 a GIANT of a teacher!!! EVERY teacher should do this
Thanks sir for such a simplistic explanation...
Black holes radiate because they are not in equilibrium with rest of universe and eventually after getiing in equlibrium (thermalised) tey should not radiate and get into equlibrium with universe with no radiation? why does the process go on forever
Hm did they release a video not so long ago to say that after reaching thermal equilibrium they go on for longer to reach complexity equilibrium
Ten minute introduction complete with multimedia presentation
Leonard: yeah I had a couple of beers before this
How can the Holographic principle be correct and reconcile with Minkowski's 4 dimensional space time? What happened to time in this scenario? Einsteins Relativity theories are predicated on the Space-Time continuum, Time
cannot be separated from space and not lead to a contradiction to Relativity.
I laughed out loud at the prominent display of blackboards...
Could it be that the rate of the expansion of the universe is somehow tied to the increasing entropy (i.e. the cosmic horizon has to expand to accommodate the additional entropy)? Some of the entropy might be stored on the internal horizons (of black holes), so could it be that the rate of black hole production is tied to the expansion of the universe? (I wonder what is the ratio between the areas of the cosmic universe and the total area of all black holes anyway - probably very little). Just some thoughts :)
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I was thinking the same thing when I was listening to these lectures. Although my mind went in the direction of; Is the fact the Universe is expanding then the cause of the increasing entropy (and the second law of TD), and thus the direction of the arrow of time? And would the direction of time reverse when the Universe shrinks?
It's probably wrong though, I don't really understand enough.
how in the world does this guy manage his time between being hitman for Walter White and giving these lectures
This comment seems to appear on every Susskind video.
If a particle is stopped it has position. If a particle is in motion it has velocity.
Its a field
1:13:20 notice that someone sneaks up and erases M^2 to m^2.
From 2016 to 2022 for Dr. Susskind's great mind is a long way.
Under-rated comment. Agree 100% In lecture 1 Susskind seemed to be hinting is that very few cosmologists are genuinely asking: What does it mean to say "We have an explanation for the Observable Universe" ?
I got lost in lecture 1 when I felt I was being told "most" [intelligent, consicous] observers would expect to find their galaxy to be the only one in existence. Surely with 10^79 particles and 13 billion years, more than one galaxy could exist simultaneously? Besides we observe billions of galaxies, so there must be some "seeding process" of dust clouds, and these lead to more entropy, more "states", more "degrees of freedom" [orbitals, atomic nucleii, chemical compounds, sequences of chemical compounds, ..., lives..., minds...] than could ever be "represented" by the "bit count" (aka "information content") of the diffuse gas because that "hydrogen everywhere, no stars" is an "information desert". What we see is after one or two local wash-rinse-dry stellar lifecycles we have 90 odd elements.
12:20 wave particle duality
With/out gravity
Photon = Space
Polarisized Directions of time
Your position in spacetime with dimensional dimensions of spacetime.
I did keep track on the constants but with this rationale the result seems to differ from the right formula by a factor of 1/8π^2 . Anybody could help me?
R=2GM/c^2 ,∂R=2G/c^2 ∂M
∂E=2πℏc/λ, ∂M=∂E/c^2 =2πℏ/cλ=2πℏ/cR
∂R=(2G/c^2)* 2πℏ/cR =4πℏG/(c^3 R), R∂R=4πℏG/c^3
A=4πR^2,∂A=8πR∂R=(32π^2 ℏG)/c^3 ???
Thanks in advance.
Well, the partial derivatives seem to be unclear, e.g. what are you differentiating with respect to? Plus, ∂R is ℏG/Rc^3. since R=GM/c^2 not 2GM/c^2.
@@josephlau13d77 Each diferencial is considering the energy increment by each photon falling in the black hole (follow the lecture for details). R=2GM/c^2 is the Schwarzschild radius (not GM/c^2).
"I always use Z for the vertical axis, I don't know Y". And nobody laughed.
Video starts at 9:19 ( pre 9:19 is Some annoying person that won’t interest your curiosity for coming here ) your welcome 🙏
Lol
For the first 9 minutes we are treated to some spotlight hogging ramble intro, a xerox of Feynman, off camera "aren't I clever?" quieter than the audience.
I hope the actual lecture is worth sitting through that.
are sunspots appearing to be on the surface of the sun a consequence of the holographic principle? Sunspots are black holes for sure
You mean, somebody actually erased the blackboards after Feynman wrote on them? ;)
Entropy means (I'm referencing/explaining from what I have researched and learnt myself) that over a given/defined/speciific amount of time, order loses definition, until it becomes chaotic/undefined. Basically; all things/life must end/die.
I don't understand why you would state "hidden information is entropy..." unless I've misinterpreted what you mean/have explained in this lecture? Either way, I find this subject very interesting and "scary".
*Yahshua The Messiah Saves."
Peace, love, prayers,
TJ
David Grusch brought me here with his creepy statements. I have been thinking about the possibility of the UAVs described using some tech based on understanding some aspects of the black holes, is crazy. Especially to imagine a cube flying in a clear sphere, which to me personally resembles what Mr Susskind mentioned the maximum entropy of the chosen sphere, could these crafts use some understanding of the black holes? By creating small black holes? Am i crazy? Perhaps haha!
When nothing crossed the horizon for Alice how the information got lost? She still has information about everything.
I am trying to figure this too. It will take me a while. My initial impression is that polarization is best looked for inside a holographic image. The dust cloud on the edges. Well not one motion can be tolerated on one particle or it would collapse. Say like 189/945. But I have to try to grasp what the history is saying. Many years of scientific study. These educators have something profound to say.
Because she really doesn’t know where Bob is now. He’s not really there. He actually was sucked into the black hole - so he’s not still at the horizon.
If she doesn’t know where he is, she cannot measure, because there is not enough information. Not to mention, entropy. Ala hologram.
Hmm, sorry but there is something fundamental about conservation of information that i do not get. Doesnt chaos tell you that initial starting conditions that differ, grow esponentially with time. Therefore looking reasonably far back in time, very tiny changes in the initial conditions, change the present dramatically. Eventually looking far enouph back, these tiny changes in the initial conditions with large effect on the present, become smaller than the uncertainty principle, and therfore the past can not be reconstructed?? where is my mistake ?
+Philippe durrer When we talk about conservation of information on an event horizon it is scrambled, you can not reconstruct Bob but everything is there. Every piece of information in him is represented on the horizon as viewed by Alice, also the way he is scrambled, but there is no methodology that can reconstruct him. As the black hole evaporates it looses it's information storing capabilities and the frozen image of Bob will get more and more fuzzy as the photons radiates away from the black hole over the next trillion years, or so. The escaping photons energy is determined only by the size of the black hole so they no longer carry information of anything other than the size of the black hole they originated from. So Alice can watch Bob disintegrate unimaginable slowly .
My own wild guess:
I don't know if Bob, if he turns around and look at Alice, would be able to watch the next trillion years flash by, as to him the entire universe would be sped up? Does Bob experience time dilation in free fall as he approaches c on his way to the singularity?
+Tore Lund Except technically you could reconstruct Bob, that's the point. Not with technologies we have today, but you technically could.
That is what I'm saying, but maybe not expressed clearly: Scramble, as in scrambled eggs has lost information. Scrambled as in cryptography, has not. In a hologram you have a pattern of interference lines that corresponds to a 3D point, but which intersections between multiple lines correspond to which point is non regressive to us, but it is not scrambled eggs, there is a perfect order and reproducibility, we just can't figure it out.
The tricky point is as when an old black hole evaporates, information will be lost as it's event horizon surface area decreases and the elementary particles ejected will have less information. Is there an upper limit of complexity for objects in the universe? Does the same loss of information applies to the universe in general. Does the universe forget its history far in the future when the only matter left is black holes evaporating away?
+Tore Lund I think we will eventually come to a concrete conclusion that the information in a black hole is not lost. I think Hawking's recent paper is a step in that direction. It also seems to borrow from the Holographic Principle somewhat :)
It would be nice if it didn't. The holographic principle is cutting edge right now. Math is being developed to calculate entanglement as information storage with error correction (Edward Witten). The quantum computer might be a natural phenomenon after all. Personally I can't wait for the holographic principle to be become the "holographic theory" with some numbers behind it to tell us how.
Time just gets shorter until time exists no more!
The fourth is Dan
1:18:53 "Bob".
Good job 😮😅😊
Thankyou
That joke at the beginning about the introducer needing the introduction more than Prof. Susskind was pretty droll.
Who says scientists can't be funny?
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ok, smoke some cerebral weed and absorb this idea completely. it becomes understood irregardless... the idea that we observed reality from many perspectives and explained it to each other
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E=MC^3 lol
it's actually E^2 = p^2c^2 + m^2c^4 relativistically
Cor, the bloke who introduced him isn't at all jealous, is he? Laughs it off, but he's still hogging the podium almost ten minutes in.
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