THANK YOU STANFORD, from South Africa! I may never get a Doctorate, I may never become a physicist, but I can still gain knowledge and information through great education institutions making their lectures available online.
I'm so, soo glad Stanford is uploading these lectures. Making this sort of knowledge available to everyone is what makes this school one of the best in the world =)
So true. A cup of coffee + online lectures or just studying yourself from a book or other kind of source just wins drinkin 100-0 (I do enjoy sipping whiskey sometimes instead of coffee)
Imagine sticking your head into the photon sphere and seeing the back your own head. The photo sphere sounds like a niche spot to set up a Barbers shop.
This one is my personal favorite of this incredible series which has taught me GR as in depth as I had sought for. I need to meet Professor Suskind. He’s my favorite String Theorist.
all of Susskind's lectures are awesome....but this one really takes the cake !.....this is just sooo cool....man if they had this when I was a kid....thanks again Lenny & Stanford
its great that a mastermind of Leonard's stature & Stanford supply this to the public... its too good to be true....."someone" may put a stop to it.....shhhhhhhh
Lecture 7 is now available on iTunes.(released 11/13/2012) Stanford, could you please do RUclips-upload too. (iTunes is highly resources consuming on my old windows-PC) I'm awaiting eagerly another one of these marvellous lectures. Thank you !
1:37:00 mark (Alice throwing Bob into a black hole) , wouldn’t Alice only have those hyperbolic coordinates if she was accelerating away from the black hole ?
My favourite part about this whole lecture series is that the Prof. only doesn't mind answering questions because it means he can take a bite of his cake or a sip of his coffee xD
20:23 ”Looking down on this thing, if were looking down from the future we’d see...” My mind was instantly incinerated trying to imagine looking down from the future.
Point mass leads to 'idealized solution', probably the source of the point singularity. Newton predicts g=0 at the center of earth, although it is billions of tons. Does the tremendous g of a BH, the same symptom?
finally some physics, and can do it all with special relativity and classical mechanics, no general involved in this one and lectures 1 - 5 were just geometry, long wait for the fysix
First of all thank Stanford and thanks Professor. In second place i want to know if mathematics of lie derivatives and groups you know that differential geometry play a role in relativity or if it is used in its development. So thanks again saludos desde Argentina.😀
this guy is a national treasure....thank Christ for him ! (metaphorically speaking)....world...we apologize for Trump...but we can offer you this as recompense
Susskind has written a very good book on the topic of black holes called The Black Whole War. He goes into detail with the problems discussed in the 2nd half of this video. Check it out
The part of this lecture from 1h8m to 1h47m blew my mind, but also clarified a lot of questions I had about what goes on around a black hole from various perspectives. I understand the math, but am still struggling to understand the concept of how the coordinates of space and time flip inside the event horizon. And, can proper time continue past the singularity? Anyway, really good lecture series so far. The first few lectures were dry, but the geometry math had to be introduced somehow.
Nah, proper time comes to an end at the singularity. In fact, judging by the hyperbolic spacelike shape of the singularity, I suspect that any infalling object, once inside the horizon, will hit the singularity in a constant (or near-constant) time regardless of how it starts accelerating once inside.
Yes it is the regular Hamilton action but as applied to the context of GR. You can have hamiltonian action for any system. Infact the Hamilton's equation in the context of Quantum Mechanics are precisely Schrodinger's equation but there too its referred as Hamiltonian not something as Schrodingerian and this is due to the fact that It was Rownian Hamilton who first formulated the principal of Least Action (To stationarize the action) to derive the Euler-Lagrange equation and apply them in the context of Dynamics to get the Hamilton's Equations.
The lectures are not in good order,for instance the lecture 5 should be followed by parallel transport and not by black hole.Where is the real continuation of lecture 5?Thank for help
So Alice gets away with murdering Bob? She can always point to him being outside the event horizon, so he's not dead (yet). Seriously, this is the best explanation I've seen of black holes. I've seen it done with a lot more maths, and a lot less understanding.
I somehow do not get this explanation of r = 3MG for a photon sphere. I get a photon with a given E and L and I solve his equation F^{1/2} * L / r = E, and I get r. Changing E and/or L results in different r. My argument cannot be correct so it seems that E and L are not independent. What am I missing here?
Changing the values of E or L does not affect the final value of r = 3mG. E is removed as to find the maxima, you differentiate the function with respect to r, then set it equal to 0. This gives you (3mGL - rL)/r^3(F^0.5) = 0. Multiply by r^3(F^0.5) giving you 3mGL - rL = 0. Now, you can remove L from this equation giving you r = 3mG. Therefore, the radius is independent of E and L because they no longer show up in the equations.
I been waiting for # 7 like a kid 4 Xmas ..# 7 and # 8 are on itunes..cant really complain cuz these fantastic vidz are free....but Stanford if you read these comments....please upload here asap.....my computer gets like 1 fpm...running itunes....of course i can DL then watch....but am short on space as well.....fine if apple give u a kickback or whatever....but was supprised that 2 more lectures were up on there before here....maybe they ask u to wait ....so they can call it exclusive ...idk
Some energy tensor of vaccum in general relativity is not zero. Detail in '82. Energy Tensor in General Relativity' on this website: sites.google.com/view/physics-news/home/updates
@@Dominik-wt5hv Yes, but to see clearly this aspect you have to use a metric different from the Schawchild one, studied by Prof. Susskind: You have to use the Kerr's metric
The subject GR is indeed a course for a Masters Student but this course can be followed by an undergrad as well since a lot of the rigor of differential geometry and Classical Field theory is omitted for the sake of the intended audience.
1:52:00 - Lame answer. In other words I do not know what I am talking about. Also in the top Quadrant everything moves faster than light. How does Bob (or anything) go into that Quadrant ever? On one hand he says these are just co-ordinates - OTOH he says Bob goes here - bob goes there - so which is it? Does it mean that all these craziness can be resolved by proper co-ordinate choice? Not a good video to learn from - too much hand waving going on here.If the space becomes time and time becomes space, won't the lightcone flip 180 degrees?
That is incorrect. Velocity of a particle is determined by the slope of x/t, so you can enter with a velocity lower than speed of light, but light you emit will never reach out. Also Saying you can not enter ever is incorrect, because that's the part of the time cone with time-like intervals, so it means the intervals which you actually live in. Your whole life is in that cone and you will never leave it, when talking about you sitting at the origin of the coordinates. From that perspective, Bob will simply emerge from infinity in the same way he will never leave from the perspective of Alice. Light cone does not flip, because it is the light cone of the reference frame, not the particle.
Someone just claimed Stanford created matter from nothing. He then gave me the link and I saw that it was talking about a photon-photon accelerator that created an electron and positron. I mean, he had the paper-- he gave me the link. I just... Dahhh... Just... DAAHH!
Take away all visible freqency light stimulus and you are are left with black. We experience black with our brain. Zero optical stimulus. But still an experience.
18:29 This is something only a very select few can ever appreciate, and if you are more than the average homo sapien, you can exist on this plain of awareness, of understanding. Without that high awareness, this seems mundane and arbitrary, and that's an infinite pity ha.
At first is seemed odd, but later you start to love how easy going Lenny is and he is the best in the world at teaching the most complicate physics ever, so he can eat and drink as much as he likes lol
@@randymartin5500 I love his lectures, but I don't agree that "he can eat and drink as much as he likes." He can't also fart and burp as much as he likes. Doing things well for free is not a license for bad manners.
THANK YOU STANFORD, from South Africa!
I may never get a Doctorate, I may never become a physicist, but I can still gain knowledge and information through great education institutions making their lectures available online.
Amen!
I'm so, soo glad Stanford is uploading these lectures. Making this sort of knowledge available to everyone is what makes this school one of the best in the world =)
i would rather spend an afternoon watching this than being drunk and falling all over the place.
thanks stanford, and leonard.
I sometimes watch while getting drunk! Then I reach a point where I have to stop (the lecture).
So true. A cup of coffee + online lectures or just studying yourself from a book or other kind of source just wins drinkin 100-0
(I do enjoy sipping whiskey sometimes instead of coffee)
do both life is short
I get drunk and stoned while watching this… it’s the BEST 🎉some red wine and herbs… and this content…. Oh my gawd. It’s my lill slice of heaven ❤
Mind blown, that proof for evaluating the curvature of the event horizon was brilliant.
Imagine sticking your head into the photon sphere and seeing the back your own head. The photo sphere sounds like a niche spot to set up a Barbers shop.
Only sad thing your entire body would bee torn to the subatomic level for you to have a nice haircut :).
@@dhritimanroyghatak2408 depends on how large the black hole is.
with the only prob that the barber would not be able to see the front of your head
This one is my personal favorite of this incredible series which has taught me GR as in depth as I had sought for. I need to meet Professor Suskind. He’s my favorite String Theorist.
the zoom in on Ⲝ at 1:12:35 has me in bits, gotta love the physicist's handwriting
all of Susskind's lectures are awesome....but this one really takes the cake !.....this is just sooo cool....man if they had this when I was a kid....thanks again Lenny & Stanford
These are all very precious, but this one strikes me as being particularly beautiful and gem-like. Thank you Prof. Susskind and Stanford.
I am absolutely loving this series. What an extraordinary teacher. Thank you!!
Reading the new book on GE along with listening is especially illuminating. Thanks to all.
Lenny @ his best.....# 7 & 8 really take the cake !.....huge thanks to him & Stanford
in this lesson we are missing subtitles. You can insert them? can you insert subtitles?Thank you
Student asks a question:
Leonard Susskind: It's cookies time!
its great that a mastermind of Leonard's stature & Stanford supply this to the public...
its too good to be true....."someone" may put a stop to it.....shhhhhhhh
Lecture 7 is now available on iTunes.(released 11/13/2012)
Stanford, could you please do RUclips-upload too.
(iTunes is highly resources consuming on my old windows-PC)
I'm awaiting eagerly another one of these marvellous lectures.
Thank you !
Fantastic courses. I had to start with L's Classical Mechanics and Special Theory to get to this point, and I'm glad I did. Intense stuff.
from where did you learn them?
1:37:00 mark (Alice throwing Bob into a black hole) , wouldn’t Alice only have those hyperbolic coordinates if she was accelerating away from the black hole ?
My favourite part about this whole lecture series is that the Prof. only doesn't mind answering questions because it means he can take a bite of his cake or a sip of his coffee xD
So much better than watching CNNs coverage of American politics!!!!!
yes I think Im starting to get this now ! Very well explained, thanks !
This needs to be added to the appropriate Playlist, please, and more when they arrive?
20:23 ”Looking down on this thing, if were looking down from the future we’d see...” My mind was instantly incinerated trying to imagine looking down from the future.
feel free to try.
Point mass leads to 'idealized solution', probably the source of the point singularity. Newton predicts g=0 at the center of earth, although it is billions of tons. Does the tremendous g of a BH, the same symptom?
finally some physics, and can do it all with special relativity and classical mechanics, no general involved in this one and lectures 1 - 5 were just geometry, long wait for the fysix
First of all thank Stanford and thanks Professor. In second place i want to know if mathematics of lie derivatives and groups you know that differential geometry play a role in relativity or if it is used in its development. So thanks again saludos desde Argentina.😀
this guy is a national treasure....thank Christ for him ! (metaphorically speaking)....world...we apologize for Trump...but we can offer you this as recompense
Susskind has written a very good book on the topic of black holes called The Black Whole War. He goes into detail with the problems discussed in the 2nd half of this video. Check it out
The part of this lecture from 1h8m to 1h47m blew my mind, but also clarified a lot of questions I had about what goes on around a black hole from various perspectives. I understand the math, but am still struggling to understand the concept of how the coordinates of space and time flip inside the event horizon.
And, can proper time continue past the singularity?
Anyway, really good lecture series so far. The first few lectures were dry, but the geometry math had to be introduced somehow.
Nah, proper time comes to an end at the singularity. In fact, judging by the hyperbolic spacelike shape of the singularity, I suspect that any infalling object, once inside the horizon, will hit the singularity in a constant (or near-constant) time regardless of how it starts accelerating once inside.
why does alice follow coordinate time and bob follows proper time?Why cant it be other way round?
superposition was a interesting lecture
Is this the regular Hamiltonian action? If it originates from GR what is its name in the bibliography? Certainly not the Einstein action...
Yes it is the regular Hamilton action but as applied to the context of GR. You can have hamiltonian action for any system. Infact the Hamilton's equation in the context of Quantum Mechanics are precisely Schrodinger's equation but there too its referred as Hamiltonian not something as Schrodingerian and this is due to the fact that It was Rownian Hamilton who first formulated the principal of Least Action (To stationarize the action) to derive the Euler-Lagrange equation and apply them in the context of Dynamics to get the Hamilton's Equations.
so nice to fall asleep to, thanks
In the sting Theorie i propose write time at first coordinate and T at last if you want spin that it is easyer
Or Serch you the spin vektors where we are? 🤔
Xitne 🙄
A black hole is a very bad thing to hide behind from your enemy - Leo Tzu
The lectures are not in good order,for instance the lecture 5 should be followed by parallel transport and not by black hole.Where is the real continuation of lecture 5?Thank for help
So Alice gets away with murdering Bob? She can always point to him being outside the event horizon, so he's not dead (yet).
Seriously, this is the best explanation I've seen of black holes. I've seen it done with a lot more maths, and a lot less understanding.
I somehow do not get this explanation of r = 3MG for a photon sphere.
I get a photon with a given E and L and I solve his equation F^{1/2} * L / r = E, and I get r. Changing E and/or L results in different r.
My argument cannot be correct so it seems that E and L are not independent. What am I missing here?
firstly you differentiate F^{1/2}r^{-1} to obtain the maxima or 3MG. secondly L is independent of maxima.
Changing the values of E or L does not affect the final value of r = 3mG. E is removed as to find the maxima, you differentiate the function with respect to r, then set it equal to 0. This gives you (3mGL - rL)/r^3(F^0.5) = 0. Multiply by r^3(F^0.5) giving you 3mGL - rL = 0. Now, you can remove L from this equation giving you r = 3mG. Therefore, the radius is independent of E and L because they no longer show up in the equations.
@@JamesSmith-fn8zd do you use the product rule or the quotient rule or chain rule?
@@chengwang2596 where does the 3 come from for MG? Do you use the product rule, and law of exponents to differentiate both F^{1/2} and r^{-1} ?
I been waiting for # 7 like a kid 4 Xmas ..# 7 and # 8 are on itunes..cant really complain cuz these fantastic vidz are free....but Stanford if you read these comments....please upload here asap.....my computer gets like 1 fpm...running itunes....of course i can DL then watch....but am short on space as well.....fine if apple give u a kickback or whatever....but was supprised that 2 more lectures were up on there before here....maybe they ask u to wait ....so they can call it exclusive ...idk
Some energy tensor of vaccum in general relativity is not zero.
Detail in '82. Energy Tensor in General Relativity'
on this website:
sites.google.com/view/physics-news/home/updates
If the black hole is rotating will the angular momentum still conserved?
yes
@@Dominik-wt5hv Yes, but to see clearly this aspect you have to use a metric different from the Schawchild one, studied by Prof. Susskind: You have to use the Kerr's metric
Great video!
Awesome stuff! Thank you
May God bless you sir
Why is this video not coming up for me?
Is it a graduate level course ?
Raj Gohil no, continuing studies: theoreticalminimum.com
The subject GR is indeed a course for a Masters Student but this course can be followed by an undergrad as well since a lot of the rigor of differential geometry and Classical Field theory is omitted for the sake of the intended audience.
I would rather spend an afternoon trying to mesh this into quantum physics
❤Thank you very much
why not both?
Relativeradgeneration theore exemplifikast neoimagem the possiblist dell capacitetion wich all possible forem all is relative
Very interesting lesson
1:52:00 - Lame answer. In other words I do not know what I am talking about. Also in the top Quadrant everything moves faster than light. How does Bob (or anything) go into that Quadrant ever? On one hand he says these are just co-ordinates - OTOH he says Bob goes here - bob goes there - so which is it? Does it mean that all these craziness can be resolved by proper co-ordinate choice? Not a good video to learn from - too much hand waving going on here.If the space becomes time and time becomes space, won't the lightcone flip 180 degrees?
That is incorrect.
Velocity of a particle is determined by the slope of x/t, so you can enter with a velocity lower than speed of light, but light you emit will never reach out.
Also Saying you can not enter ever is incorrect, because that's the part of the time cone with time-like intervals, so it means the intervals which you actually live in. Your whole life is in that cone and you will never leave it, when talking about you sitting at the origin of the coordinates. From that perspective, Bob will simply emerge from infinity in the same way he will never leave from the perspective of Alice.
Light cone does not flip, because it is the light cone of the reference frame, not the particle.
My comment I shall put down after the entire lecture!
1:32:59 it iiiz what it iiiz
agreed, nice to be able to have all this just for free o.o
Nice
wonder if i can take my drinks with me to open courseware
Someone just claimed Stanford created matter from nothing. He then gave me the link and I saw that it was talking about a photon-photon accelerator that created an electron and positron. I mean, he had the paper-- he gave me the link. I just... Dahhh... Just... DAAHH!
p.s. other videos are working so it's not my computer it must be this video? Anyone else having trouble now?
@1:43:20
Its an Technik to oriantation, so it must slowing down 😑
31:04 "Anglumentum" lol
pfew, this is rather complicated?
Americans need to here of espresso, small coffee, not 1 litre of coffee per mug
The whole lecture is about how bad Schwarzschild coordinates are.
Watch it at x1,25 speed. Just an advice.
Print 2 line around an massive point and Look where the 🥐 is 🤣
Take away all visible freqency light stimulus and you are are left with black. We experience black with our brain. Zero optical stimulus. But still an experience.
The Brain worked and to much involving brake the learn proces
Gah. Too zoomed in and too much camera movement! I like to see the other material on the board too!
💙🤓🖐️
If we now calculate particle we must sqare W of time and you get with E every Element you want 🤣
And so you messure c in every time and mass
The ony one whats unnown are the proportties of elements thats chage with volume E
Serch you the perfekt spin vektors? 🤔
I’m relativity dumb compared to Mr. Suskind.
18:29 This is something only a very select few can ever appreciate, and if you are more than the average homo sapien, you can exist on this plain of awareness, of understanding. Without that high awareness, this seems mundane and arbitrary, and that's an infinite pity ha.
feel lost
Anderson Susan Taylor Lisa Brown Michael
Hall Brian Jackson Richard Jones Linda
His favourite color is black.
Thumbs up if you agree !
wtf
100th comment
If we talk now about lerning write and read it isnt good talk to much 😑 and to fast 🤦♂️
My child is 7 and its work very good
He can it complet in first half year if the proces work in the lerning haw totay with math, his Limit is over 💯
FOR THE LOVE OF GOD, PLEASE STOP EATING COOKIES WHILE TALKING. THOSE SMACKING AND GULPING SOUNDS-DISGUSTING!!!!!!!!!!!!!!
So ask for your money back, and stop watching.
At first is seemed odd, but later you start to love how easy going Lenny is and he is the best in the world at teaching the most complicate physics ever, so he can eat and drink as much as he likes lol
@@randymartin5500 I love his lectures, but I don't agree that "he can eat and drink as much as he likes." He can't also fart and burp as much as he likes. Doing things well for free is not a license for bad manners.