Stephen Hawkings disease is almost like a black hole, its almost like he knew something to prove himself but his brain came to a state where he himself could no longer conceive it.
Honestly I believe that much of what physics tells us is very speculative. just because math adds up at so far (which it doesn't seem to even be doing if you ask me) doesn't necessarily mean that the picture the math paints is congruent to reality. It would have to be complete, and flawless. Both of which it seems it is not. More like a very creative mathematical story that gets tweaked to make it hold water whenever it appears to be incorrect.
hmm, that doesn't seem so paradoxical really. You could say the same thing about an observer watching a traveler going close to the speed of light - the "stationary" observer sees the space compression and surmises that the traveler must have been crushed inside the craft. The traveler of course experiences no such thing. Is this event horizon thing so different?
@TheRationalizer schrodinger's cat experiment was a reductio ad absurdum proof that it's improbable that uncertainty has effects on the macro-scale; not an actual thought experiment explaining the uncertainty principle. i'm not a physics major or anything, i'm simply a messenger from the land of rationalism.
TOTALLY DIFFERENT THINGS DOOD, WASN'T SUPPOSED TO BE A REAL THING
My comment was a joke. Schrödinger's cat was an analogy for how on the quantum level things seem to be in every state at the same time until such a point that we interact with them in order to measure them (i.e. "look at them")
if Alice fells into the black hole and survives the event horizon (in case of a very large mass black hole), you do we know it? It is an information about a state behind the event horizon... yet we know... but Bob sees Alice frozen at the horizon... But if Bob knows physics he knows that Alice is alive. Where does this info come from to Bob?
A quick paradox from the legend of Zelda majora's mask. In the clock tower, the mask salesman stands waiting, but inside the clock tower, time dosen't pass. As soon as you leave, the in-game clock reappears. So when you leave the mask sales man and come back, how much time passes from his perspective? Answer, an infinite amount of time.
well no fucking shit he was becoming less influential..the guys paralyzed...give him a break..im sure if he didnt have his disability hed be all over the place throwing equations left right and centre solving the mysteries of the universe just like that....
Physics explains how The Matrix works. The funny thing is that once something is understood it is only a matter of time before the entire mankind and not just The One can alter the lines and build it as we all need it to be. :)
Why all the rebellion against the idea of not being able to reconstruct events from current evidence? The Deterministic Universe got tossed out by quantum theory. Much of what was left got tossed out by Chaos Theory. Not much of the scientific philosophy of Newton's time is left intact, even if Newton's not-quite-right equations still apply most of the time.
@sbergman27 So the myth goes. There's some truth in that, but not a lot. It's pushed by pseudoscientists who want to present QM or chaos theory as some sort of mysticism.
QM and chaos theory are massive breakthroughs, but the fundamental principles of causality and determinism have remained completely intact. It's become a lot stranger than it was (re-expressed as things like information conservation or unitarity) but they're still very well-defined and very much alive.
@TheBobathon:Onlyfor suitably loose definitions of "completely intact". Newton's view said if we know the exact positions, velocities, etc. of every particle then we can predict the future! QM says we can't ever even know the exact position and velocity of a single electron. It's hard to argue that determinism has just become more complicated. It's dead. But there are still some rules standing between that and a totally anarchic and random universe. It's "causality" that's still mostly intact.
@sbergman27 you're right in the practical sense - we can't know the state of a system or predict where it will be in the future. But the fundamental principle is intact at the core of quantum physics and chaos theory. The state of an undisturbed quantum system will evolve according to 100% deterministic laws. Of course we have to interact with systems to know anything about them... but the universe could be taken as the system.
Chaos theory is also deterministic. But not predictable.
@TheBobathon:QM is deterministic only to a certain level. It's a little like considering Statistical Thermodynamics as being the fundamental theory of matter and energy. I probably shouldn't be using QM and Chaos in the same breath (YT char limit!) since they are unpredictable in very different ways. Habit. I tend to lump them together in my responses to people who seem to have some "deep" philosophical concern about Free Will, which has always seemed a silly topic to me, all things considered.
@TheBobathon:To the extent that there *are* laws, but that what they can say is fundamentally fuzzy. We'd have to agree upon a precise definition of "determinism" in order to meaningfully agree or disagree whether QM is. (If a tree falls in the forest, and...) Einstein remarked that there is no reason to expect that the 'U' should be simple enough for us to understand, but that it is. We've had to fall back from that. Necessary refinements has made physics more and more complex. But
@TheBobathon:(continued) But fundamental uncertainty was a bite of wormwood that has fundamentally changed physics. It puts a lid on not only what is predictable, but what is knowable. So I keep thinking back to AE's statement about there not being a reason to expect the U to be understandable at its fundamental levels. Maybe he should have ended his statement there. But... within its domain, QM explains the data in a way that nothing else does. So that's that. At least for now.
@TheBobathon Addendum: To me, determinism implies perfect predictability *in principle*. I would consider QM to be nondeterministic. However, I would consider a "Chaotic" system to be fundamentally, if not practically, deterministic. Chaos Theory, itself, wouldn't prevent an infinitely powerful and infinitely precise computer from predicting the results of the butterfly's flapping. QM's uncertainty is more profound.
@sbergman27 OK. Yes, I agree it depends on definition of the word. Your question was about the discussion in the video - I think the point is that there IS a principle, which is (rightly or wrongly) referred to as determinism, upon which the whole of theoretical physics still relies. If your definition of determinism implies predictability, then I agree, it won't correspond to what you mean...
@sbergman27 ...As I understand it (and I'm risking tying myself in knots here) this principle can be framed in terms of conservation of information, which is very well-defined, and it relates to the unitarity of evolution operators in QM. It's independent of any probability, uncertainty, stochastics, statistics or measurements. As far as I know, that kind of analysis can only build up from a theory in which information is conserved. Conservation laws are absolutely essential in physics...
@TheBobathon: "this principle can be framed in terms of conservation of information, which..."
As long as we frame it this way, I would agree. I guess my nit was with applying the word 'determinism' to something that bears little resemblance to anything Newton would have seen as deterministic. But... looking back, I think I'm the one who introduced that word into this thread. ;-) My original intent was to strike up an enlightening discussion. It seems to have worked.
@TheBobathon: I'm going out on a limb here... but would it be reasonable to say that it's "OK" to have uncertainty regarding things which haven't happened yet... but that once it's been observed, it's wave function collapsed, that it *must* be set in stone, and a precise and well defined causal path *must* exist? If so, another question comes to mind. What about things that happened but were not observed? Which, of course, gets us into the realm of "what does "observed" mean, in a QM sense.
@sbergman27 I think this is where you get answers like 'sort of'. Questions framed with intuitively defined words don't generally have neat answers in QM. You could say that wavefunction collapse really means that the measuring device (and, ultimately, you) becomes entangled with the system being observed. If device D observes X, the system DX becomes entangled such that D and X share information. When YOU look at the reading on D and get entangled with it, that's when I get a bit confused. :-)
Specifically, what would you have to say about similarities and differences between information conservation looking forward and looking back in time?Is there a difference? It seems to me more, or more physically precise, rules night apply looking back. Re: observer entanglement, we're in good company. I recall Steven Weinberg simply stating that the the Copenhagen Interpretation was "just hopeless" and then pretty much leaving it at that.
@sbergman27 QM is time-symmetric. You can be disentangled as well as entangled - it's not a one-way thing. it's just the way subsystems evolve within a larger system (like DX, or DX+you, or DX+you+everyone that you tell...). Unitarity in QM implies that the evolution of states is deterministic and time-reversible. That's why information conservation is such a big deal. In the real world there are far more particles than measurements. That's where thermodynamics takes over.
Such interpretations of QM are *strictly* deterministic and linear: the deterministic unitary evolution of the (never collapsing) wavefunction is the whole picture. The non-deterministic non-linear part of QM comes from actual wavefunction collapse ("objective reduction") .. if such a mechanism exists. There are various ideas but nothing concrete yet, which is why many-worlds is so popular .. it requires no extension to existing theory.
In many-worlds interpretations there is no randomness or free will, you perceive the macroscopic branch that you're in by the weak anthropic principal that hey, you had to get some branch, so here's your one and it's fairly typical. To me many-worlds seems like a retreat back to the Newtonian past, albeit with a nature that is rather profligate with the ol' universes, so I lean towards OR (i.e. QM being incomplete), but it's just a hunch.
@BagarozziBoi Hunches aside, I agree with all of that. My take is that while we have a variety of interpretations all of which are consistent with reality, 'reality' (if such a thing can even be defined in any way that would satisfy our little minds) is most likely more profound and strange than any one of them. I tend to think more in terms of entanglement-as-measurement because I just find it easier. And I like it... until I think too much about its ontology! I try not to take it seriously :-)
The entanglement-as-measurement viewpoint is *explicitly* a many-worlds interpretation of QM, even though many off its proponents don't like to draw attention to the fact. In this picture there is no objective "collapse of the wavefunction", which is seen as a statistical convenience for throwing away the parts of the state that represent the alternative macroscopic outcomes, now that they have become effectively inaccessible parallel worlds (with negligible residual interference).
@sbergman27 Nothing is 'set in stone' unless a conservation law that says it is. A good measuring device will be one that obeys some conservation law. If you observe something about X, and the quantity you're observing is conserved for X, and the reading on your device D is also conserved (it'd be a useless device if it wasn't) then X will correspond to the reading so long as the conservation law still applies.
If you measure position, it's NOT set in stone because you didn't measure momentum=0
@TheBobathon : "If you measure position, it's NOT set in stone because you didn't measure momentum=0"
I tend to forget this bit. Precise measurements *are*, in principle, possible in QM as long as your experiment does not concern itself with some conflicting property. Any property? Or are things like position and velocity special? If you want to measure the position of a particle (in principle) with 100% accuracy, can you measure *anything* else about it at the same time? Spin?
@sbergman27 Er... yes you can. Dunno how to explain though, except in terms of the maths. You can measure two observables at the same time if they have the same eigenvectors. Or... you can make two measurement operations at the same time if the operators commute. Spin and momentum commute. Spin of A and spin of B commute.
Momentum/position are related by Fourier transforms, which (I think) means they're as non-commutative as it's possible to be. Same for energy/time, angular momentum/angle.
@TheBobathon: Intuitively, it seems like if one property *necessarily* changes the other over time, then you can't measure both at the same time with 100% accuracy. Velocity necessarily affects future distance. But velocity and spin are orthogonal. The one has nothing (necessarily) to do with the other's value in the future.
@sbergman27 I don't know if that has anything to do with it... it's not the way I tend to see it, but you could be right. The only way to get a definitive answer is to pop into Hilbert Space and check it out!
And be careful with the word 'orthogonal' - it might not mean what you think :-)
Actually, Susskind has done a series of lectures on this. You'll probably get a lot more sense from him. I haven't watched the whole thing, but his style is crystal clear. It's here: watch?v=0Eeuqh9QfNI
@TheBobathon: "...be careful with the word 'orthogonal' - it might not..."
Yeah, I wondered about that after I posted. In CS, when we say orthogonal, we mean the one doesn't have anything to do with the other. But it's field-specific jargon based upon a fanciful interpretation of "at right angles".
And thanks. I've been watching some of Susskind's Stanford CE lectures. But I haven't watched that series.
1. State vectors within the Hilbert Space of a single system can be orthogonal - that means if it's in one state, you definitely won't observe it to be in the other. So the state of having a definite spin of +1 and having a definite spin of -1 are orthogonal.
2. If you have two separate systems, not entangled at all, they each exist in their own little Hilbert Space, then the two entire Hilbert Spaces are orthogonal, and they don't interfere with each other.
@sbergman27 you're right, though, to say that no state of definite position can ever be orthogonal to any state of definite momentum (of the same particle).
@sbergman27 ...The word uncertain is also a bit misleading in QM. Meassurements might be probabilistic, but the evolution of the state of a system is not. Position and momentum aren't properties of a system - they're the outcomes of observing it from outside, i.e. becoming entangled with it. The system just evolves, and the laws appear to be entirely deterministic. What we can know is another matter! The information is 'there' and is conserved in the universe. That's why they're making a fuss.
it is not necessarily true in case of giant mass black holes, you can live up to an 30-40 minutes after passing through the event horizon of a billion star black hole
So after 30 years of research Hawking was wrong on this specific question. I wonder how many other theories out there are also wrong, yet are still being worked on by physcists. At least on this one, the error and solution was solved and pointed out by Leonard.
Ohhh yes thats how gullible people are .... they don't have their own minds .... i just knew he was wrong .... put the pity card away and just say it for what it is WRONG.
It was no theory. There was no mathematics. No experimental confirmation. If you want to know one bogus hypothetical model physicists are working on, then it is string theory. Their imaginary strings probably don't exist.
To stephen hawking, it seems to me that black holes r 4 ever getting larger ,which indicates to me that matter never escapes untill it finally explodes into a new existance
To Steven Hawking(the most famous scientist in the world at this point of time & space in this reality) i believe that matter can be lost from 1 reality & perhaps reappear in an other reality, or perhaps it simply reappears in a different time?? or space??,i feel this in my heart cos i'm a paradox myself ,actually i'm paradox69 even though here i'm Box0069 kind regards from Max D whom has an old computer manufactured in 2123 & is 10years old
I thought Feynman/Witten were very well known public figures? Especially Feynman, and Witten increasingly given the publicity string theory has been recieving...
No. I attend a Tier one research university as a mathematics major. Most students haven't even heard of String Theory, let alone its key figure, Edward Witten. As for Feynman, Americans are generally morons when it comes to science. They would rather know the names of religious figures, athletes, and movie stars.
@Solutory You could also get hold of Prof. Leonard Susskind's 'The black hole war' which is a very accessible and readable book on the subject.
Also check out Susskind's lectures on the Stanford university channel, although this is much more math based. However he also teaches physics and required mathematics there too, so you could learn the required classical and Quantum physics there too.
8:30 on is absolutely beautiful
gabrown87 6 days ago
I can't imagine the degree of his bravery.
craigz06 4 weeks ago
Stephen Hawkings disease is almost like a black hole, its almost like he knew something to prove himself but his brain came to a state where he himself could no longer conceive it.
OddOpinion 1 month ago
Gender Age
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O_O Dan im 25 years younger than everyone. But i'm not majoring in this though.
Jmerino7 5 months ago
i thought that black hole could just move stuff... like it falls into a diffrent dimmention that we cant see
photonman54 5 months ago
Science is the constant study of what we thought we knew.
ArtisanTony 6 months ago
Who wrote that paper talked about at 04:10?
WritingFighter 6 months ago
@WritingFighter Juan Maldecena i think ?
reallyflasshy 4 months ago
Physics is a work in progress, we may come to realize that a good amount of it was wrong some day in the future.
LBNANY 6 months ago
Honestly I believe that much of what physics tells us is very speculative. just because math adds up at so far (which it doesn't seem to even be doing if you ask me) doesn't necessarily mean that the picture the math paints is congruent to reality. It would have to be complete, and flawless. Both of which it seems it is not. More like a very creative mathematical story that gets tweaked to make it hold water whenever it appears to be incorrect.
LBNANY 6 months ago
I get the infamous "physics envy" when watching these vids. What an incredible human endeavor.
ZachRose88 6 months ago
hmm, that doesn't seem so paradoxical really. You could say the same thing about an observer watching a traveler going close to the speed of light - the "stationary" observer sees the space compression and surmises that the traveler must have been crushed inside the craft. The traveler of course experiences no such thing. Is this event horizon thing so different?
jeffreyburr 8 months ago
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qwert1819161 9 months ago
The idea suggests one can be both alive and dead at the same time?
When we first get to test this we should try it on a cat named "Schrödinger" :)
TheRationalizer 9 months ago
@TheRationalizer schrodinger's cat experiment was a reductio ad absurdum proof that it's improbable that uncertainty has effects on the macro-scale; not an actual thought experiment explaining the uncertainty principle. i'm not a physics major or anything, i'm simply a messenger from the land of rationalism.
TOTALLY DIFFERENT THINGS DOOD, WASN'T SUPPOSED TO BE A REAL THING
clancym1 4 months ago
@clancym1
My comment was a joke. Schrödinger's cat was an analogy for how on the quantum level things seem to be in every state at the same time until such a point that we interact with them in order to measure them (i.e. "look at them")
TheRationalizer 4 months ago
if Alice fells into the black hole and survives the event horizon (in case of a very large mass black hole), you do we know it? It is an information about a state behind the event horizon... yet we know... but Bob sees Alice frozen at the horizon... But if Bob knows physics he knows that Alice is alive. Where does this info come from to Bob?
szjozsi 9 months ago in playlist Hawkins' Information Paradox
A quick paradox from the legend of Zelda majora's mask. In the clock tower, the mask salesman stands waiting, but inside the clock tower, time dosen't pass. As soon as you leave, the in-game clock reappears. So when you leave the mask sales man and come back, how much time passes from his perspective? Answer, an infinite amount of time.
Kyensai 10 months ago
This has been flagged as spam show
*Correction*
4:49
"Our memories were safe"
LOL! WTF? Honestly, must they dramatize this that much?
June28July 11 months ago
"Our memories were safe"
LOL! WTF? Honestly, must they dramaticize this that much?
June28July 11 months ago
Blackholes have a singularity that will shink to non existance.
Blackholes could be an intermediate period in the life cycle
Picture The 11th dimension as a miniscule ultraviolet belt of life.
A billionth of a millimeter wide, carrying the energy flow from expiring life sources,
across dimensional space.
Life forms enter the 11th dimension(could be a blackhole?) after a period of
non activity(death)
This would explain the Blackhole Equation (alive and dead at the same time).
11thDim 1 year ago
er? I don't think we have evolved brains to cope with this intuitively.
simpsonmark 1 year ago
well no fucking shit he was becoming less influential..the guys paralyzed...give him a break..im sure if he didnt have his disability hed be all over the place throwing equations left right and centre solving the mysteries of the universe just like that....
clovelywindheaven 1 year ago
Stephen Hawkin is a spiritually enlightened man who really has access to the real cosmic sense.
jaxxcorbin 1 year ago
@jaxxcorbin - you're talking crap. :)
Mike51020 1 year ago
@Mike51020 Do you know what a "figure of speech" is?
chill bro.
jaxxcorbin 1 year ago
@jaxxcorbin - I know all about the "cosmic mind" crap lol. This is a Science video, please keep all the New Age claptrap off the comments. Peace :)
Mike51020 1 year ago
@Mike51020 Peace :)
jaxxcorbin 1 year ago
@Mike51020 yeah. f*ck you. i hope you get mouth cancer and rectal cancer simultaneously
ExEffingDee 1 year ago
@ExEffingDee - I hope you just fuk off.
Mike51020 1 year ago
@YellowCakeKid Hahaha, Stephen Hawking is more talented than i thought ! :)
joseftran 1 year ago
Physics explains how The Matrix works. The funny thing is that once something is understood it is only a matter of time before the entire mankind and not just The One can alter the lines and build it as we all need it to be. :)
GShock112 1 year ago
If god exists, the god is Stephen Hawking.
HyperGolem 1 year ago
He has a wife? How do they get it on? Mind over matter?
joseftran 1 year ago
@joseftran hes prolly got one hell of a vibrator
YellowCakeKid 1 year ago
Why all the rebellion against the idea of not being able to reconstruct events from current evidence? The Deterministic Universe got tossed out by quantum theory. Much of what was left got tossed out by Chaos Theory. Not much of the scientific philosophy of Newton's time is left intact, even if Newton's not-quite-right equations still apply most of the time.
sbergman27 1 year ago
@sbergman27 So the myth goes. There's some truth in that, but not a lot. It's pushed by pseudoscientists who want to present QM or chaos theory as some sort of mysticism.
QM and chaos theory are massive breakthroughs, but the fundamental principles of causality and determinism have remained completely intact. It's become a lot stranger than it was (re-expressed as things like information conservation or unitarity) but they're still very well-defined and very much alive.
TheBobathon 1 year ago
@TheBobathon:Onlyfor suitably loose definitions of "completely intact". Newton's view said if we know the exact positions, velocities, etc. of every particle then we can predict the future! QM says we can't ever even know the exact position and velocity of a single electron. It's hard to argue that determinism has just become more complicated. It's dead. But there are still some rules standing between that and a totally anarchic and random universe. It's "causality" that's still mostly intact.
sbergman27 1 year ago
@sbergman27 you're right in the practical sense - we can't know the state of a system or predict where it will be in the future. But the fundamental principle is intact at the core of quantum physics and chaos theory. The state of an undisturbed quantum system will evolve according to 100% deterministic laws. Of course we have to interact with systems to know anything about them... but the universe could be taken as the system.
Chaos theory is also deterministic. But not predictable.
TheBobathon 1 year ago
@TheBobathon:QM is deterministic only to a certain level. It's a little like considering Statistical Thermodynamics as being the fundamental theory of matter and energy. I probably shouldn't be using QM and Chaos in the same breath (YT char limit!) since they are unpredictable in very different ways. Habit. I tend to lump them together in my responses to people who seem to have some "deep" philosophical concern about Free Will, which has always seemed a silly topic to me, all things considered.
sbergman27 1 year ago
@sbergman27 Free Will is a silly topic, don't think it mixes well with physics. :-)
Re QM - to what level?
TheBobathon 1 year ago
@TheBobathon:To the extent that there *are* laws, but that what they can say is fundamentally fuzzy. We'd have to agree upon a precise definition of "determinism" in order to meaningfully agree or disagree whether QM is. (If a tree falls in the forest, and...) Einstein remarked that there is no reason to expect that the 'U' should be simple enough for us to understand, but that it is. We've had to fall back from that. Necessary refinements has made physics more and more complex. But
(continued)
sbergman27 1 year ago
@TheBobathon:(continued) But fundamental uncertainty was a bite of wormwood that has fundamentally changed physics. It puts a lid on not only what is predictable, but what is knowable. So I keep thinking back to AE's statement about there not being a reason to expect the U to be understandable at its fundamental levels. Maybe he should have ended his statement there. But... within its domain, QM explains the data in a way that nothing else does. So that's that. At least for now.
sbergman27 1 year ago
@TheBobathon Addendum: To me, determinism implies perfect predictability *in principle*. I would consider QM to be nondeterministic. However, I would consider a "Chaotic" system to be fundamentally, if not practically, deterministic. Chaos Theory, itself, wouldn't prevent an infinitely powerful and infinitely precise computer from predicting the results of the butterfly's flapping. QM's uncertainty is more profound.
sbergman27 1 year ago
@sbergman27 OK. Yes, I agree it depends on definition of the word. Your question was about the discussion in the video - I think the point is that there IS a principle, which is (rightly or wrongly) referred to as determinism, upon which the whole of theoretical physics still relies. If your definition of determinism implies predictability, then I agree, it won't correspond to what you mean...
TheBobathon 1 year ago
@sbergman27 ...As I understand it (and I'm risking tying myself in knots here) this principle can be framed in terms of conservation of information, which is very well-defined, and it relates to the unitarity of evolution operators in QM. It's independent of any probability, uncertainty, stochastics, statistics or measurements. As far as I know, that kind of analysis can only build up from a theory in which information is conserved. Conservation laws are absolutely essential in physics...
TheBobathon 1 year ago
@TheBobathon: "this principle can be framed in terms of conservation of information, which..."
As long as we frame it this way, I would agree. I guess my nit was with applying the word 'determinism' to something that bears little resemblance to anything Newton would have seen as deterministic. But... looking back, I think I'm the one who introduced that word into this thread. ;-) My original intent was to strike up an enlightening discussion. It seems to have worked.
sbergman27 1 year ago
@TheBobathon: I'm going out on a limb here... but would it be reasonable to say that it's "OK" to have uncertainty regarding things which haven't happened yet... but that once it's been observed, it's wave function collapsed, that it *must* be set in stone, and a precise and well defined causal path *must* exist? If so, another question comes to mind. What about things that happened but were not observed? Which, of course, gets us into the realm of "what does "observed" mean, in a QM sense.
sbergman27 1 year ago
@sbergman27 I think this is where you get answers like 'sort of'. Questions framed with intuitively defined words don't generally have neat answers in QM. You could say that wavefunction collapse really means that the measuring device (and, ultimately, you) becomes entangled with the system being observed. If device D observes X, the system DX becomes entangled such that D and X share information. When YOU look at the reading on D and get entangled with it, that's when I get a bit confused. :-)
TheBobathon 1 year ago
@TheBobathon: "I think this is where..."
Specifically, what would you have to say about similarities and differences between information conservation looking forward and looking back in time?Is there a difference? It seems to me more, or more physically precise, rules night apply looking back. Re: observer entanglement, we're in good company. I recall Steven Weinberg simply stating that the the Copenhagen Interpretation was "just hopeless" and then pretty much leaving it at that.
sbergman27 1 year ago
@sbergman27 QM is time-symmetric. You can be disentangled as well as entangled - it's not a one-way thing. it's just the way subsystems evolve within a larger system (like DX, or DX+you, or DX+you+everyone that you tell...). Unitarity in QM implies that the evolution of states is deterministic and time-reversible. That's why information conservation is such a big deal. In the real world there are far more particles than measurements. That's where thermodynamics takes over.
TheBobathon 1 year ago
Such interpretations of QM are *strictly* deterministic and linear: the deterministic unitary evolution of the (never collapsing) wavefunction is the whole picture. The non-deterministic non-linear part of QM comes from actual wavefunction collapse ("objective reduction") .. if such a mechanism exists. There are various ideas but nothing concrete yet, which is why many-worlds is so popular .. it requires no extension to existing theory.
BagarozziBoi 2 months ago
In many-worlds interpretations there is no randomness or free will, you perceive the macroscopic branch that you're in by the weak anthropic principal that hey, you had to get some branch, so here's your one and it's fairly typical. To me many-worlds seems like a retreat back to the Newtonian past, albeit with a nature that is rather profligate with the ol' universes, so I lean towards OR (i.e. QM being incomplete), but it's just a hunch.
BagarozziBoi 2 months ago
@BagarozziBoi Hunches aside, I agree with all of that. My take is that while we have a variety of interpretations all of which are consistent with reality, 'reality' (if such a thing can even be defined in any way that would satisfy our little minds) is most likely more profound and strange than any one of them. I tend to think more in terms of entanglement-as-measurement because I just find it easier. And I like it... until I think too much about its ontology! I try not to take it seriously :-)
TheBobathon 2 months ago
The entanglement-as-measurement viewpoint is *explicitly* a many-worlds interpretation of QM, even though many off its proponents don't like to draw attention to the fact. In this picture there is no objective "collapse of the wavefunction", which is seen as a statistical convenience for throwing away the parts of the state that represent the alternative macroscopic outcomes, now that they have become effectively inaccessible parallel worlds (with negligible residual interference).
BagarozziBoi 2 months ago
@sbergman27 Nothing is 'set in stone' unless a conservation law that says it is. A good measuring device will be one that obeys some conservation law. If you observe something about X, and the quantity you're observing is conserved for X, and the reading on your device D is also conserved (it'd be a useless device if it wasn't) then X will correspond to the reading so long as the conservation law still applies.
If you measure position, it's NOT set in stone because you didn't measure momentum=0
TheBobathon 1 year ago
@TheBobathon : "If you measure position, it's NOT set in stone because you didn't measure momentum=0"
I tend to forget this bit. Precise measurements *are*, in principle, possible in QM as long as your experiment does not concern itself with some conflicting property. Any property? Or are things like position and velocity special? If you want to measure the position of a particle (in principle) with 100% accuracy, can you measure *anything* else about it at the same time? Spin?
sbergman27 1 year ago
@sbergman27 Er... yes you can. Dunno how to explain though, except in terms of the maths. You can measure two observables at the same time if they have the same eigenvectors. Or... you can make two measurement operations at the same time if the operators commute. Spin and momentum commute. Spin of A and spin of B commute.
Momentum/position are related by Fourier transforms, which (I think) means they're as non-commutative as it's possible to be. Same for energy/time, angular momentum/angle.
TheBobathon 1 year ago
@TheBobathon: Intuitively, it seems like if one property *necessarily* changes the other over time, then you can't measure both at the same time with 100% accuracy. Velocity necessarily affects future distance. But velocity and spin are orthogonal. The one has nothing (necessarily) to do with the other's value in the future.
sbergman27 1 year ago
@sbergman27 I don't know if that has anything to do with it... it's not the way I tend to see it, but you could be right. The only way to get a definitive answer is to pop into Hilbert Space and check it out!
And be careful with the word 'orthogonal' - it might not mean what you think :-)
Actually, Susskind has done a series of lectures on this. You'll probably get a lot more sense from him. I haven't watched the whole thing, but his style is crystal clear. It's here: watch?v=0Eeuqh9QfNI
TheBobathon 1 year ago
@TheBobathon: "...be careful with the word 'orthogonal' - it might not..."
Yeah, I wondered about that after I posted. In CS, when we say orthogonal, we mean the one doesn't have anything to do with the other. But it's field-specific jargon based upon a fanciful interpretation of "at right angles".
And thanks. I've been watching some of Susskind's Stanford CE lectures. But I haven't watched that series.
sbergman27 1 year ago
@sbergman27 Ah, ok. Two contexts:
1. State vectors within the Hilbert Space of a single system can be orthogonal - that means if it's in one state, you definitely won't observe it to be in the other. So the state of having a definite spin of +1 and having a definite spin of -1 are orthogonal.
2. If you have two separate systems, not entangled at all, they each exist in their own little Hilbert Space, then the two entire Hilbert Spaces are orthogonal, and they don't interfere with each other.
TheBobathon 1 year ago
@sbergman27 second one fits with what you're saying from CS (but maybe not how you used it for QM!).
CS = computer sci? What's CE?
TheBobathon 1 year ago
@sbergman27 you're right, though, to say that no state of definite position can ever be orthogonal to any state of definite momentum (of the same particle).
TheBobathon 1 year ago
@sbergman27 ...The word uncertain is also a bit misleading in QM. Meassurements might be probabilistic, but the evolution of the state of a system is not. Position and momentum aren't properties of a system - they're the outcomes of observing it from outside, i.e. becoming entangled with it. The system just evolves, and the laws appear to be entirely deterministic. What we can know is another matter! The information is 'there' and is conserved in the universe. That's why they're making a fuss.
TheBobathon 1 year ago
whered he come up w/ the whole black hole projector thing, and ppl looking 2d.. was that totally just made up in his head? lol
myth1c 1 year ago
I hate the false representation of a black hole as a hole in space , it only can be represented us such in the space time fabric
InitialDAmine 2 years ago
many are wrong but fortunately we call some theories and others laws for a reason.
johnbruder01 2 years ago
The gravitational tidal forces would destroy a person well before reaching the event horizon. This is stupid.
Zeldovich 2 years ago
it is not necessarily true in case of giant mass black holes, you can live up to an 30-40 minutes after passing through the event horizon of a billion star black hole
szjozsi 2 years ago
According to....?
Zeldovich 2 years ago
This comment has received too many negative votes show
the ultimate snobish physic...
badsign1980 2 years ago
So after 30 years of research Hawking was wrong on this specific question. I wonder how many other theories out there are also wrong, yet are still being worked on by physcists. At least on this one, the error and solution was solved and pointed out by Leonard.
mrocean21 2 years ago 2
who knows, maybe everything we ever know about science are errors.. minute it may be, it's still erroneous.
jetlagsyndrome 2 years ago
Ohhh yes thats how gullible people are .... they don't have their own minds .... i just knew he was wrong .... put the pity card away and just say it for what it is WRONG.
MrDoublehappy 2 years ago
@mrocean21
It was no theory. There was no mathematics. No experimental confirmation. If you want to know one bogus hypothetical model physicists are working on, then it is string theory. Their imaginary strings probably don't exist.
LogicalFlawDetector 1 year ago
To stephen hawking, it seems to me that black holes r 4 ever getting larger ,which indicates to me that matter never escapes untill it finally explodes into a new existance
Box0069 2 years ago 2
Matter never escapes? did you just hear about Hawking radation? Matter and energy are exchangeable.
Zeldovich 2 years ago
To Steven Hawking(the most famous scientist in the world at this point of time & space in this reality) i believe that matter can be lost from 1 reality & perhaps reappear in an other reality, or perhaps it simply reappears in a different time?? or space??,i feel this in my heart cos i'm a paradox myself ,actually i'm paradox69 even though here i'm Box0069 kind regards from Max D whom has an old computer manufactured in 2123 & is 10years old
Box0069 2 years ago
tnx for these video's collection
c8est8said 2 years ago
I love physics. It describes the very fundamentals of reality, but tends to be the most complex field of study.
HotSauce147 3 years ago 29
@HotSauce147 Fill the black hole with weed, black hole gets plugged, everyone gets high.
The end
motoxidation 1 year ago
awesome all 5 videos!
lalokullo 3 years ago 4
I thought Feynman/Witten were very well known public figures? Especially Feynman, and Witten increasingly given the publicity string theory has been recieving...
KaoriBlue 4 years ago 2
@KaoriBlue
No. I attend a Tier one research university as a mathematics major. Most students haven't even heard of String Theory, let alone its key figure, Edward Witten. As for Feynman, Americans are generally morons when it comes to science. They would rather know the names of religious figures, athletes, and movie stars.
LogicalFlawDetector 1 year ago
I guess to understand you have to watch the whole thing.
Solutory 4 years ago 18
and more than once, lol
GABRIEL1977P 3 years ago 4
@Solutory You could also get hold of Prof. Leonard Susskind's 'The black hole war' which is a very accessible and readable book on the subject.
Also check out Susskind's lectures on the Stanford university channel, although this is much more math based. However he also teaches physics and required mathematics there too, so you could learn the required classical and Quantum physics there too.
watch?v=32wIKaLkvc4
marsCubed 1 year ago
Confusing but interesting stuff.
Midnightbong0 4 years ago 3