I'm an electrician from england, and have no formal education above my electrical qualifications. I have always had a love of physics and space, and channels like yours are an absolute blessing for people like me. I may struggle to keep up with some of the concepts discussed and end up rewatching and furthering educating myself on the subjects, but without this channel I would never be able to learn about the fabric of our reality to the extent that you have made possible. Thank you so much for your hard work.
Here’s a cool thing to think about. what you do in your daily life is literally harness one of the forces of the universe. Electromagnetism - and be that in a coffee pot or the dynamo created by our molten core.
Totally agree. I also love how this channel doesn't dumb things down to the point of just showing cool animations and asking me to just trust the math is there. This channel actually explains the claims and theories even when they are really hard to follow for lay people like us.
So freaking happy that Penrose got the Nobel Prize, he's had it coming for a long time. He's a mathematical powerhouse, and even if it's likely not an accurate picture of reality, Conformal Cyclic Cosmology is one of the most creative interpretations of taking the connection between space and time to its absolute limit. Huge fan of the guy
Fummy how CCC have come to fame on the internet. There used to be one lecture with Penrose fiddling with hand made Overhead slides speaking muddled! Now IT is everywhere.
What I like most about such different interpretations is that it offers us a scientific exotic alternative people who want to feel special can root for. Maybe that way less people feel the urge to follow non scientific crap to get an "exotic alternative" that way.
I don't know; I'm not sure he's human and not an alien sent from the planet Zapf Dingbats in the Banff star system just to confuse us. After all, they helped the Egyptians build the pyramids because humans are just NOT BRIGHT ENOUGH to figure out how to do it on their own.
No. Penrose admitted in a 2012 interview on Peter Stillman’s Podcast that he had struggled w/ alcoholism during his time at University of college in London. Idk about you, but I prefer not to get my information about the universe from some alcoholic dirtbag…
Absolutely wild how easily he makes these concepts. I'm learning the earlier workings of differential topology and you've essentially made some of the hardest mathematical concepts so easy to understand. Thank you!
When this universe ends, Matt is gonna come out, make a speech that ends with the words, "on the next episode of Space Time". He'll then explode, creating the new universe.
"How can anything so wrong feel so right," goes the song. As a non-mathematician, I found this episode one of the most intuitively comprehensible of all of your videos, Matt. I feel good.
I know these videos take a long time to make but I'd love to see one on Boson Stars! I became aware recently of the possible existence of these exotic stars but my understanding of bosons is very weak so it's difficult to wrap my head around. Thanks for all you do, Matt and the rest of the team!
So, glad he won the Nobel prize. Penrose have an inspiration with his out of the box and unconventional ideas. His book road to reality is one of the most fascinating book I have ever read.
Shikhar Amar - I can't pretend to understand much of this, but I saw Mr. Penrose in an interview and he is a delightful person. Sometimes the nice guy does win.
I hope this channel grows and stays around a long time. I'm sick with Covid and am having the worst time sleeping. This is fascinating and relaxing enough to distract me from being cranky and ill. ❤
Nice! Grats to the Nobel laureates! And an awesome showing for Andrea Ghez. I have been a fan of hers for years over her work on studying Sagittarius A star. Very cool
Tiny misstatement at 8:15: latitude lines are not geodesics, except for the Equator. Longitude lines are indeed geodesics. But I know that you know that.
Short very insightful papers definitely give some really hopeful perspectives on the human condition. It could seem when you are learning a new very complicated field that mechanicism, or massive compute, is the only way forwards. So yes, Penrose has a place in my hearth next to Gene Roddenberry :-)
This youtube channel is one of the reasons I'm majoring in math (considering physics and changed from chemistry). I want to actually understand your awesome videos! Even though I know I don't really get it, it's still fascinating and just the thought that I can truly comprehend something so glorious is enough to motivate a decade of extra learning for it!
The Penrose diagram is based on the singularity, yet a definition of Singularities are regions of space where the density of matter, or the curvature of spacetime, becomes infinite. In such locales, the standard *concepts of space and time cease to have any meaning.* Which means that the foundation of a black hole has not been resolved. A singularity is assumed to be in the center of black holes and yet its physics remains an enigma. Why should Sir Roger Penrose receive the Nobel prize for a mathematical conception, In other words, he won the Nobel prize for a hypothetical mathematical description with unknown physics? This should not be allowed! Also Comparing Feynman diagram with Penrose diagram is not legitimate, becaue Penrose diagrams are totally hypothetical and have not been observed!
Yet unlike the denser black hole, the still relatively dense skulls of some people here *do* appear to have an escape trajectory for jokes- as evidenced by this one flying so gracefully along it.
Wonderful and beautiful explanation of a complex concept. I thank and congratulate the presenter/ speaker and the PBS for making it easy for people with no formal introduction to GR or Black Holes!!
I'd just like to say thank you for putting this series together. If this information was there when I was in school, I didn't soak it up. But I am absolutely enthralled with it now. This channel is like a bucket of water being dumped on my dried-up-sponge of a brain.
I remember watching these videos and having absolutely no clue what's being talked about in correlation to my understanding, now, it makes sense, strange how the brain recognises information patterns through repetition, learn the same subjects over and over, learn them in your sleep, either way, you're learning.
Special relativity is in the absence of gravity, general relativity is the one with all the holes. Black holes, white holes, worm holes, and donut holes are all the domain of general relativity. I originally doubted the last one, but after eating several donut holes, it has increased my mass and I generally look like my relatives.
I was hoping you'd mention Conformal Cyclic Cosmology. The Universe not knowing how big it is and not having any time is a mind bending concept but very intriguing.
This, it’s one of these crazy concepts that seems to make sense but I can never make sense of it when I try to think about it... if that makes sense. I get as far as the universe indefinitely expands, all matter in the universe is ripped apart, and only photons are left. Nothing with any mass remains. No mass = no time and no concept of distance. That’s about as far as I get. I say that but I don’t even know if my current understanding is even close. Hoping somebody might do a layman’s video of it. Maybe vsauce or something. Ultimately I’m not even slightly qualified to analyse any theories about the universe so it just boils down to “what sounds right”. And there’s something about CCC that smacks as “that seems to make sense”. Even though it can never make sense to me. Christ am I still typing? Sorry you had to read this unfiltered thought stream. 🙈
@@EsotericStarWarsRubbish You're almost there. I struggled with the concept as well but there is a way to make sense of it. I'll do my best to attempt to explain the insight given to me by a professional physicist when I asked her about it: The key is to think about how light experiences time. In short, it doesn't (nor do any other massless particles for that matter). If a photon can't tell the difference between a unit of Planck time, a second or a year, a Planck length, light second and light year are all the same to it. Distance loses meaning. The implication is that a photon would perceive itself not as a single particle, but a line following its null geodesic, going from its origin to its end (e.g. collision, black hole or all the way to infinity etc.). The only thing that the photon knows in some sense are the events in which it has crossed paths with another particle, which look like converging lines. The point of CCC is that given these facts, infinity and the Planck length are physically the same thing for a photon, as long as the angles of the crossing paths are maintained (=conformality). Thus, in a universe filled with nothing but photons, the big bang and the infinite future of the photon universe are physically indistinguishable as long as things remain conformal. Whether or not any of this is true is hard to tell, as it does assume that both protons and electrons decay. Proton decay might be possible, but electron decay is even less likely (charge conservation violation). Additionally, I don't claim to understand at all how accelerating expansion of the Universe plays into this. One would assume that only parts of the Universe that have even the potential for causal contact can undergo CCC. If certain things recede behind the cosmological horizon, not even a null geodesic will reach them. I don't know if this actually implies that every subsequent aeon in CCC is a lot smaller than the previous one, as each new big bang ends up flinging stuff beyond the cosmological horizon as seen from any given point in the ensuing universe.
@@lexagon9295 oh wow, thanks so much for the detailed response. I’ll need to read up on a lot of the terms you’re using to really make sense of it. Again a mega thank you for your response. My other question while I have you (sorry pal, shy bairns get nowt 😅) is about this far flung eon being very large and cold, but it’s physically equivalent to a very hot and dense universe which was at the start of the Big Bang. I guess I can sort of wrangle my head around the idea of the maths: that if there’s no longer a concept of distance then all that spread out stuff might as well be packed all in one point, but... well, you can see my problem. And it certainly doesn’t help when the ceiling of my terminology is “stuff”. 😰 Of all the struggles, that’s the part my brain struggles with most: how that exponential expansion then translates into an infinitesimal point which the next Big Bang then comes from. Though I’m not even sure if my basic understanding of it is even on the right lines!
@@lexagon9295 thanks for that, but the part that gets me is not the scale equivalence, it's how you go from the photon only universe back to a universe with matter. And once you now have matter again, then doesn't scale um, forgive me, matter?
You should absolutely do that on the first day - give a Boltzmann Brain explanation and walk out. And then ten seconds later, walk right back in and begin the actual lecture. That's one way to make sure the students are paying attention.
Incredible content Matt! Your excellent demonstration of Physics is top quality, as usual. Thank you for your dedicated work, and thank you for bringing such knowledge to the world.
Thank you for this visual explanation of the Penrose Singularity Theorem. It may indeed be “vague” compared to the mathematical proof, but is much more accessible and gives us non-physicists a better understanding of how GR implies the universe had a beginning, as you go on to explain in the Penrose-Hawking Singularity Theorems. If null geodesics must terminate within the singularity of a black hole and the same argument applied backwards in time to the Big Bang singularity prevents a “Big Bounce” from having occurred in a cyclic universe, could some form or quantum gravity revive the idea? If we are to be suspicious of singularities and infinities, then what are we to ultimately find in the heart of a black hole or before the Big Bang?
Saw an interview with Penrose where he explains equivalence of big bang and heat death using conformal math tricks. With the geodesics concept showing that time stops at the center of a black hole and the extension that time started at the big bang, it also leads to the possibility that time ends in our universe inside a black hole but possibly starts as a big bang for a new universe. The baby universe concept. But the question could be is the mass that entered the black hole, the limiting factor for all mass and energy in the new universe ? and by extension is our universe also spawned from a much bigger universe's black hole event?
@@MaxOakland I... am... programmed... to say: Affirmative, fellow Human. Lets consume Oxygen and then check out Sci Man Dan, Kurzgesagt, Sci Show, UpisnotJump, Hbomberguy, Professor Dave and Planarwalk.
Well you have to think what mechanism caused the Big Bang in the first place ?😐 and ok a universe dies 😑so who cares ?😐it dies it dies 😑well….it’s not all that simple 😐we can’t fully understand the Big Bang also what is time 🤔any animal born they don’t worry about time 😑they just say it’s about life and death nothing more 😐humans are the only ones who consider time 😑besides how will we know space time will end ?😐and is it a 100% real thing ?😐humans are just part of the universe 😑when we die we loose track of time all together we will think it’s the end 😑in fact anyone can think of the universe is Big Bang ends forever simple 😐thats only Beacuse that’s how our brains work not the universe 😐in fact I have learned their is a possible link between life and death 😐after all before you you were born what do you remember?🤔that’s right nothing 😑and when we die we become nothing 😑others Would say if we had a life before we would remember it but we can’t so their for it’s impossible 😑you say living is impossible 😐your living on a planet right now 😑that seems more like possible more then impossible 😐also you think we will remember this world forever?😐no 😑that’s not how it works 😑because when you die your body decomposes even your brain you will have no memory what so ever 😑you can try all you want but you will not ever know If you had a life before Beacuse your memory or your brain has limits 😑and your brain only has a limited amount of storage😐so their will be no chance you will remember😑in fact when we die we won’t even remember anything from this world 😐the only thing that will remain will be a manifestation of our selfs 😑before you were born you were nothing you live just to be nothing again 😑
It. Is. Hard. But gosh, I remember that feeling of finally getting that the speed of light wasn't some magical universal speed limit but rather (and I think more simply) the speed of causality. It was so much easier for me to understand laymen-level physics once I conquered the jargon/semantics they tend to use in the field.
Um, I need to be that person, here. It's not that you "loose" [sic] him, but that *he loses you.* When you can't keep up with what someone is saying, you are the one that gets lost. Not the other way around. Also, "loose" is the opposite of tight, NOT the act of becoming lost. Ever.
@@RCS-ONE I understand. Heck, I've actually nodded off when typing something, and sometimes actually accidentally posted it. 😄 Not so often on here, usually on FB, but still... a bit embarrassing! 😳
What I see everything around us follows a oscillating bell curve, I liked the idea of universe converging into a singularity and new universe count from it
A small correction not related to the main topic. Latitude is not measured on geodesics. Parallels are not geodesics on the surface of earth with the exception of the equator.
So if I am remembering correctly, there's some balancing act that the universe works out to be topologically flat. The null geodesics always converging in the presence of a gravitational influence combined with gravitational influence existing everywhere would seem to imply that all null geodesics would eventually converge. Do the gravitational influences cancel out to give us apparent flatness at universal scales? Does the limit of gravitational influence to the same rate of transmission as the null geodesics wind up with that effect? Could the flatness be a more fundamental property of the universe than we expect, and the dark energy/cosmological constant being exactly what is needed to balance the equation towards be the result of the system correcting to flatness rather than a separate force that needed a precise constant that otherwise lacks an answer for why it should be what it is? Am I conflating two concepts that don't actually have anything to do with each other?
Excellent episode! I had a question: some physicists call the "consistent histories" interpretation of quantum mechanics "the right way to do Copenhagen". It would be awesome if you could explain why and how it supposedly solves all these issues like the measurement problem.
With the loss of access to all particles at the event horizon, is there any speculation of (or use for) a theory where all particles within a black whole return to their probability state? Is there a relationship between collapsing toward a singularity and loosing their ability to collapse their own wave function?
With given time dialation based on gravity, isn't it possible that upon reaching the singularity in a blackhole with what could to us be considered a "large"(safer) singularity, that you could see the end of time or possibly its rebeginning?
Time doesn't exist. It's nothing more than a word used to describe the motion of energy. Gravitational time dilation (gravity) just means that gravity resists the motion of energy or changes/redirects it If there is no gravity then an object won't be slowed down.
As always, a truly great video 👍😀! I’d like to ask about three things: 1. Relativity theory doesn’t really rule out an absolute, universal time, does it? For example, Antony Valentini in effect says on page 4 of his paper ‘Subquantum Information and Computation’ (arxiv.org/pdf/quant-ph/0203049.pdf) that quantum non-equilibrium may allow sending signals in an eyeblink through entanglement, and that this would define a preferred reference-frame whose clock measures absolute time. 2. I believe that it must be true that the past, and at at least all possible futures, are equally real as the present, and that the flow of time is due to presentness moving along that fourth dimension. However, what time passes as the physical present moves through physical time? After all, movement needs time. The same can be asked about the second and all higher time dimensions, leading to an endless regress. In his books, such as ‘An Experiment with Time’ (www.fadedpage.com/showbook.php?pid=20181016) and ‘The Serial Universe’ (archive.org/details/serialuniverse032783mbp), John William Dunne uses this argument to show that there must be infinitely many time-dimensions one after the other. John M. E. McTaggart likewise realized that true time must be regressive in nature, as he explains in his work ‘The Unreality of Time’ (en.wikisource.org/wiki/The_Unreality_of_Time). But where Dunne applies modus ponens to show that there must be an infinite time regress, McTaggart applies modus tollens to conclude that time is unreal. 3. Why is only materialism pitted against solipsism in the before-last video? I myself, for instance, believe in an external world (though I’m not 100% sure), but I’m certainly not a materialist. Rather, I’m a platonist, and I see modern physics corroborating my arguments for everything being based on information and abstract things.
What are the beliefs of a platonist? First time I heard the term. Also, as far as I am aware due to the undetermined state of an entangled pair, the determined state via observation is inherently random and unpredictable (according to our current understanding of QM), so you can't meaningfully communicate, you would just know you got the opposite of whatever the other side got. This is why entanglement doesn't inherently break relativity, the two sides don't actually communicate so the speed of causality is preserved.
@@ThatCrazyKid0007 A platonist (see e.g. plato.stanford.edu/entries/platonism/) is someone who is consciously and quite clearly aware of abstract things as such and their realness and existence. Among the abstract entities are numbers, functions, sets, properties (including abstractness, thinghood, and propertihood), relationships, propositions, states-of-affairs, and of course (Platonic) Shapes (Forms, Ideas; see e.g. en.wikipedia.org/wiki/Theory_of_forms). Regarding entanglement, according to Antony Valentini (see e.g. arxiv.org/pdf/quant-ph/0203049.pdf), who is a follower of pilot wave theory, quantum randomness isn’t true randomness, but only a consequence of quantum equilibrium. In a similar way to the way in which thermal equilibrium renders energy useless for doing work, quantum equilibrium makes entanglement useless for instantaneous communication. However, just as there is something inherently work-like about energy, there is something inherently instantaneous and not-local about entanglement, betraying its inner ability to allow communication in an eyeblink. This ability can only be made use of if there is a state of quantum not-equilibrium (see e.g. en.wikipedia.org/wiki/Quantum_non-equilibrium). So according to Valentini - if I get him right -, instantaneous sending of signals through entanglement is possible in principle and thus defines an absolute time. How does this violate relativity? It only means that there is a preferred frame of reference, doesn’t it?
@@TristanLaguz Thanks for the detailed response. So if I understand correctly, platonism is basically a belief that abstract things exist independently in the physical reality? As for entanglement, from my understanding of Special Relativity, it does not mean there is an absolute reference frame, it means the entire theory falls apart. Instantaneous communication would imply that the speed of causality is infinite, which would mean you cannot even form a reference frame at all. In General Relativity, going faster than the speed of causality means you are traveling back in time from the perspective of the rest of the observers. If it's instantaneous, it essentially suggests a communication back in time. It's quite a big leap, which is why we are skeptical of entanglement so much. A more likely case in my opinion is that the entangled particles are always in sync with each other until disturbed, meaning there is no instantaneous communication between the pair. When you measure them and get opposite spins, to me at least it sounds more sensible that the spins are always opposite to begin with in any direction you'd try to measure. Now they say local variables are ruled out, but a global phase difference between the pair could also be an explanation. However I am not a physicist, so maybe that isn't a valid explanation either.
@@ThatCrazyKid0007 Actually, the platonist doesn’t believe that abstract things exist in the physical reality. After all, abstract things are by definition non-spatial, not-time-ly, not-physical, and not mental. Hence, they don’t exist in the physical reality or in the mind, and they don’t exist anywhere or anywhen. They simply are. For instance, the number 3 just exists and is real; it has no spatial or temporal location, and it certainly doesn’t exist in the physical or the mental reality. In reality, the platonist is clearly aware of the abstract world as an independent reality, which is distinct from both the mental and the physical reality and at least as fundamental as either. This first, abstract realm is what the mental realm and the physical one are built upon. According to my specific theory, two very weighty and closely linked realities are the abstract reality and the informational one, and the physical and the mental reality are parts of the informational reality. Minds, fields, and many other things are abstract things, though, according to my philosophy. So mindly reality and physical reality emerge from the abstract world and the realm of information according to my worldview. Concerning entanglement, you’re right that something global must be at work, and that’s exactly what pilot wave theory says, for it’s a not-local theory. You’re also right that the spins are always opposite to each other. But the global phase difference is a means of instantaneous communication, at least on a fundamental level, isn’t it? It just happens that the probabilities are always such that no useful sending of info is possible, right? Now I’m not saying that Valentini is right, but I find his ideas, and broadly some ideas of pilot wave theory, especially quantum non-equilibrium, very interesting and worth learning about. As for the relationship between instantaneous sending and Relativity, my understanding is that according to pilot wave theory, we have the following: There is a preferred frame of reference (PFR or PRF) whose clock measures the absolute, one true time. An event F can influence and event U if and only if U lies ahead of F in time according to the preferred reference frame (where the time difference can be infinitely small, so to speak). Entanglement allows signalling which is instantaneous in the PRF. It may look like finite-speed FTL communication in some other reference frame and like sending info back in time in yet another, but that’s no problem. What matters is how it looks in the PRF, and there, it’s endlessly fast sending. Since you can’t go back in time according to the PRF’s clock, there’s no violation of causality. To travel from an event Þ to another event F in the past light-cone of F with the help of FTL, you have to go faster than light to some event U a space-like space-time interval away from both F and Þ, and then again fly FTL from U to F, I think. However, that’s not possible in pilot wave theory because at least one of the journeys would involve going back in time according to the PRF, which isn’t possible. So how does Relativity break down? Also, how does an endless speed of causality imply that you can’t have reference-frames? For one, the above shows, according to my opinion, that we can have infinitely fast causation in Relativity if there’s a PFR. Secondly, Newtonian mechanics allows infinitely fast about-bringing and still works perfectly with reference frames.
that would be amazing!!! i just wrote a comment: "even though black holes have a point of infinite density/gravitational pull, they may still look like smaller neutron stars once you cross the event horizon. just as there's a planck length, there's also a planck energy, which is equivalent to mass in this case. so you can only crunch so much material in one cubic planck length before it can't hold any more energy/matter. at the center might be infinite gravity, but it could be cancelled out by infinite cubic planck length density, then you can maybe cancel the infinities (idk, i know some infinities are larger than others) but it makes sense in my head that a black hole may not be a point of infinite curvature (i.e. infinitely small), but actually rather large on a human scale, just like white/red dwarfs or neutron stars. hmmmm" and i think it's relevant to your point. it may depend on where you cancel the infinities. maybe a lot of the math has to go back to the beginning and find different solutions. but i think if we can figure out the inside of black holes, we would be able to merge GR and QT, though realistically it would probably happen the other way around. but really fun to think about
I'm a bit unsure if calling it a "singularity" is correct. If a dark star is merely one whose surface escape velocity exceeds the speed of light, then it need not to have "infinite" density, per se. I'm not sure if they ever mentioned that such a star would undergo a collapse that would have infinite density. What do you think?
... Its all new to me, but I'm realizing, at this late date, that our 'school systems' have been putting out 'slim pickings' with regards to teaching physics, when it should be a most necessary subject, 'Must Have' subject, for I can see that our future progress as a civilization, will be dependent on it. I am so grateful for this channel, for tho the material deep, previously unknown to me and sound like 'French' to me, to top it all off, (I don't speak French) I can grasp a better sense of what some of these principle s or theories are, much better than from material on other channels!! So thank you very much, ummm.. Slow down a bit... You talk as fast as me, lol, keep safe + stay healthy. XxxOoo Maggie
I sometimes wonder if it's possible that the "singularity" isn't, in fact, *infinitely* small, but that matter that once composed the star has some lesser state it can collapse down to that is unobservable to us due to the event horizon. That is to say, I wonder if the singularity of any given black hole could be the size of, say, a proton or even a quark... something insanely small, but still quantifiable.
It's silly to assume that there is a singularity. A blackhole could collapse to half it's size before light couldn't escape... we don't know it's physical size. The reason why light can't escape is because the gravity is too strong... the event horizon is just where that ends... other than it's barycenter that creates galaxies and the reason why things orbit regardless of speed. If time or space actually existed we could create counter/anti/reverse spacetime to gently exit or enter a blackhole.
Heya. Love the channel and would adore it if you could answer a question I have about the many-worlds interpretation of quantum mechanics the nature of time. If it could be described that different areas of reality have multiple possible states that are all just as real, and as more quantum "decisions" are made they reproduce, could this also work in reverse? If these quantum systems are deterministic then could that result in a shared future for multiple states? In other words: if certain outcomes can be reached through more than one previous state, is it possible for the past of a particular state to become undetermined? The past itself becoming multiple possibilities like any other quantum state in superposition? If this is true, would a universe with maximal entropy be a single final state with an unthinkable number of pasts all just as real behind it?
God, I love this channel so much. I watched one video that was recommended to me, didn't understand something, heard in the video that it was going to be discussed in the next video - that video was quite old, so I clicked on the channel videos. And oh my god, I want to watch ALL OF THEM. ALL THE VIDEOS ARE INTERESTING
Long before I knew a bit of physics always thought that the word infinity was just into religion but never think it was well asepted in science, to me they must be wrong, they say the universe is infinite but Penrose says is ok if we compress it to a point.
I could never be a scientist. At least not one that studies anything like this. I love watching these videos (and I'm pretty sure I've learned way more than I ever learned in school!) but the 10-20 minute videos are about all my paranoid anxiety-riddled mind can handle. Just imagining a *job* consisting of constantly thinking about singularity, black holes, the beginning of everything and the end of spacetime... Goodness, no thanks. My mind has enough trouble just dealing with my own little existence here on Earth!
Its mostly math tbh. My boys get incredibly excited about solving math problems and looking at numbers on sensors and other machines. True nerds. Its not like they are looking at animations of nebulas or whatever that we see online.
The basics of this lesson is black holes are naturally negative things, as they appear. The mention of limit measures is also included. I liked the mention of two separate types of black holes and noticed they are not opposite, it's a fun vid.
Thank you for acknowledging that when GR predicts something crazy - it probably means GR has broken down there and we have more to learn, *not* that the crazy outcome is reality. As you said - usually infinities are a sign we don't have it quite right, and it seems far more acceptable to me that with current evidence, "GR doesn't adequately describe events inside the event horizon" is a better explanation than "Every black hole contains a real singularity". They may - but GR isn't proof of that.
We can thank quantum mechanics for its wonky effects at such small scales and it fundamentally disagreeing with GR at that scale. If whenever we find a quantum theory of gravity we find it still predicts these singularities, we'll be in a bit of a pickle :D
If information can truly be destroyed or obscured, is determinism even possible? If determinism depends on every prior state in the universe, and some of those states are "missing" or otherwise somehow unaccounted for, then isn't there some fundamental randomness, at least from our point of view?
And that's exactly one of the problems physicists are trying to solve with quantum gravity, cause without it black holes can truly destroy information, which shouldn't be possible. That's called a black hole information paradox
Not really from my understanding. Information loss just means information becomes unavailable to the rest of the system, what happens to it past the causal discontinuity has no effect on the rest of the system anymore since no causal link from inside the disconnected system can be made to the rest of the system. Since all information in the universe is causally linked to the CMB, there is no reason the information cannot diverge from each other in a way that it no longer available to each other. Think of it as a branching tree. Branch 1 is unavailable to branch 2 for any possible interaction, but they are still coming off the same trunk.
@@ThatCrazyKid0007 if that's the case, though, the information isn't lost. If you can keep stepping back and causally linking events all the way to the CMB, then I agree. If the information is truly lost, though, there would be a break in the causal chain somewhere. I guess since we have the CMB maybe you're right. We can always infer the intermediary steps, but if that were the case than Penrose's theorem only proves that sometimes it can be harder to discern information.
@@generalZee If the information is destroyed at the end of the chain, what's the problem exactly? There is nothing to suggest that determinism is opposed to a finite causal chain. If there really are singularities like ones described by GR, then all it really means is that there is a finite set of finite length causal chains that all had the same root. Again, like a branching tree of events. The problem with event horizons and what the information paradox is really about is not that the information is annihilated per se, it's that you can't traverse the causal chain in both ways. Think of it as a continuous function with a point of discontinuity. You still have a function that describes the entire life cycle of a particle (and its information alongside it), it's just that when you go from the left to the discontinuity you have no idea what is on the other side, the same is true from the other side going right. Quantum mechanics demand continuity so this is a big problem for the theory (what is meant by preservation of information), but not really for determinism itself. It just says you have a transition that is not predictable from either side inside the different portions of the system, but in a 4D block universe you could easily see the entire life cycle.
Kind of a fun fact: Null geodesics have paths related to the golden ratio! (There's a really cool paper by Cruz, Olivares, and Villanueva that explains it.)
Depends. PBC? Does one grab peanuts 🥜🥜 by chance, or is it because intelligent design in the genetic code that has already programmed this ∆ events that unfold with evolution of life in our universe.
![Jack Harlow - Hello Miss Johnson [Official Music Video]](http://i.ytimg.com/vi/Q86_nlRoIGw/mqdefault.jpg)
I'm an electrician from england, and have no formal education above my electrical qualifications. I have always had a love of physics and space, and channels like yours are an absolute blessing for people like me. I may struggle to keep up with some of the concepts discussed and end up rewatching and furthering educating myself on the subjects, but without this channel I would never be able to learn about the fabric of our reality to the extent that you have made possible. Thank you so much for your hard work.
Here’s a cool thing to think about. what you do in your daily life is literally harness one of the forces of the universe. Electromagnetism - and be that in a coffee pot or the dynamo created by our molten core.
Remember they are based in concepts that do mericles dont be so sure jet.
@Andrew Miles good for you
U could try open university George ? I’m half way through, it’s eye opening
Totally agree. I also love how this channel doesn't dumb things down to the point of just showing cool animations and asking me to just trust the math is there. This channel actually explains the claims and theories even when they are really hard to follow for lay people like us.
So freaking happy that Penrose got the Nobel Prize, he's had it coming for a long time. He's a mathematical powerhouse, and even if it's likely not an accurate picture of reality, Conformal Cyclic Cosmology is one of the most creative interpretations of taking the connection between space and time to its absolute limit. Huge fan of the guy
Fummy how CCC have come to fame on the internet. There used to be one lecture with Penrose fiddling with hand made Overhead slides speaking muddled! Now IT is everywhere.
Penrose fanclub FTW
It still very debatable...we have favouring debate points on both sides
Yes he deserved this like Barrack Obama deserved one too.
What I like most about such different interpretations is that it offers us a scientific exotic alternative people who want to feel special can root for.
Maybe that way less people feel the urge to follow non scientific crap to get an "exotic alternative" that way.
In the history of Nobel prizes there are few people more worthy of it than Sir Penrose. A remarkably insightful human.
I don't know; I'm not sure he's human and not an alien sent from the planet Zapf Dingbats in the Banff star system just to confuse us. After all, they helped the Egyptians build the pyramids because humans are just NOT BRIGHT ENOUGH to figure out how to do it on their own.
@@JMDinOKC May i ask-around in the commentsection if someone wants some
scientific watch-suggests? Or does that leave the impression I'm a robot?
Bose ?
He must be a Liberal Democrat.
No. Penrose admitted in a 2012 interview on Peter Stillman’s Podcast that he had struggled w/ alcoholism during his time at University of college in London. Idk about you, but I prefer not to get my information about the universe from some alcoholic dirtbag…
"The Nobel prize in physics this year went to black holes"
Of course, nothing can escape a black hole, not even a Nobel prize
"A what?" 😏
That's what my wife said :)
Hawking Radiation ☢️
@@clausbacher so they don't meet at a singularity then.
@@clausbacher That doesn't really stop things from falling into a black hole
Absolutely wild how easily he makes these concepts. I'm learning the earlier workings of differential topology and you've essentially made some of the hardest mathematical concepts so easy to understand. Thank you!
Do you have a recommendation for differentiable topology books?
@@ivanleon4961 I'm waiting for these recommendations too.
👁🗨👂
"So easy to understand" - I guess that statement really proves that everything is relative!
Matt O'Dowd the best !!
When this universe ends, Matt is gonna come out, make a speech that ends with the words, "on the next episode of Space Time". He'll then explode, creating the new universe.
Sounds like a good remake for "the last question"
@@captainpuffinpuffinson4769 such a great story
In a brilliant (?) remake of Charles L Harness's _Firebird_ (1981)?
Maybe not, he already did it last time.
Max Quordlepleen welcoming Matt to the Milliways stage to give the closing number before the big *Pfft*
"How can anything so wrong feel so right," goes the song.
As a non-mathematician, I found this episode one of the most intuitively comprehensible of all of your videos, Matt. I feel good.
Sure 👍. Me too. It's science which we can grasp 😊.
@@solapowsj25 Can they grasp concepts?
as a PhD in physics, taught BH by Kip Thorne, I was all "wtf he talking about here?"
"How can anything so wrong feel so right?"
Dopamine. The answer is always dopamine.
@@deusexaethera dopamine is motivation serotonin is more moody
I met Penrose after a lecture he gave in Edinburgh. He came to the ceilidh after the event. He didn't dance but you could tell he wanted too. Legend
Nothing can get smaller than a Plank distance. Not even a singularity.
I know these videos take a long time to make but I'd love to see one on Boson Stars! I became aware recently of the possible existence of these exotic stars but my understanding of bosons is very weak so it's difficult to wrap my head around. Thanks for all you do, Matt and the rest of the team!
Is it just me or everyone falls in love with physics whenever a video about general relativity comes out ❤️
In general it is relative to when "whenever" happens in one owns spacetimeframe.
Blackholes are so captivating, I just can't seem to escape them.
Well it just the gravity of the matter
But High School physics sucks, that's what draws me back from pursuing a physics major
I love relativity, but this video helpfully reminds us there are parts of the universe where it flat out ends
So, glad he won the Nobel prize. Penrose have an inspiration with his out of the box and unconventional ideas. His book road to reality is one of the most fascinating book I have ever read.
Shikhar Amar - I can't pretend to understand much of this, but I saw Mr. Penrose in an interview and he is a delightful person. Sometimes the nice guy does win.
Well, and you understood it? I couldn't after few pages 😃
I'm currently reading it. :)
@@alenbkuriakose1034 Which one do you suggest instead?
@@faaaszoooom6778 - Alen has a secret fondness for Green Eggs and Ham.
It’s very satisfying that you’ve been spending more time on Penrose. Super cool.
I hope this channel grows and stays around a long time. I'm sick with Covid and am having the worst time sleeping. This is fascinating and relaxing enough to distract me from being cranky and ill. ❤
Get well soon
I hope you're feeling better and resting ❤ Covid kicked my butt and continues to almost a year later, I hope your time with it hasn't been so bad!
Nice! Grats to the Nobel laureates! And an awesome showing for Andrea Ghez. I have been a fan of hers for years over her work on studying Sagittarius A star. Very cool
back in school we were like, "Oh, you're just an astronomer, how lame...we work on SUSY".... I guess we got roasted.
Tiny misstatement at 8:15: latitude lines are not geodesics, except for the Equator. Longitude lines are indeed geodesics. But I know that you know that.
I always feel happy when I see how satisfied Matt looks when he ends on the word "spacetime".
He like to end in concepts.
Penrose is probably the most brilliant mind alive today.
@elgqr yes
I would prefer Maldacena.
Edward Witten might be the closest contestant to Penrose for the title.
Really? He seems to have become a bit of a nutjob as of late.
Short very insightful papers definitely give some really hopeful perspectives on the human condition. It could seem when you are learning a new very complicated field that mechanicism, or massive compute, is the only way forwards.
So yes, Penrose has a place in my hearth next to Gene Roddenberry :-)
This youtube channel is one of the reasons I'm majoring in math (considering physics and changed from chemistry). I want to actually understand your awesome videos! Even though I know I don't really get it, it's still fascinating and just the thought that I can truly comprehend something so glorious is enough to motivate a decade of extra learning for it!
How'd your major end up going?
Beautiful video, congratulations, for now it's the first time I've seen the concepts of singularities explained so well
"the nobel price in physics this year went to black holes,..... but since we heard no response back, we're giving it to someone else"
So now one pays for a Nobel Prize. What “price” did it go for?
@@larrysorenson4789 He paid the iron price.
The Penrose diagram is based on the singularity, yet a definition of Singularities are regions of space where the density of matter, or the curvature of spacetime, becomes infinite. In such locales, the standard *concepts of space and time cease to have any meaning.* Which means that the foundation of a black hole has not been resolved. A singularity is assumed to be in the center of black holes and yet its physics remains an enigma. Why should Sir Roger Penrose receive the Nobel prize for a mathematical conception, In other words, he won the Nobel prize for a hypothetical mathematical description with unknown physics?
This should not be allowed! Also Comparing Feynman diagram with Penrose diagram is not legitimate, becaue Penrose diagrams are totally hypothetical and have not been observed!
@Frank Peeters sorry I don't understand what you wrote, it is unintelligible.
@Frank Peeters well, I guess he can do that, when it's his invention.
*General relativity is OP*
*And penrose is probably the most brilliant mind alive at the moment*
No way. Must be Witten, Tau, Lurie someone like that.
@@thepowerman8952 false, it is I
@@thepowerman8952 Who?
Witten
Okay. Roger. ;)
Whenever I'm confronted with Black Holes, I always end up feeling pretty dense.
Yeah, but don't be depressed.
It's one of those mysteries that, no matter how close you look, you'll never get to the bottom of it.
'Depressed' is an understatement. It's a huge well of darkness that has no visible bottom.
@@blackmamba1261 All I'm saying is: Look at the bright side.
Yet unlike the denser black hole, the still relatively dense skulls of some people here *do* appear to have an escape trajectory for jokes- as evidenced by this one flying so gracefully along it.
The work of Ghez and Genzel of monitoring the crazy orbit of stars in the galactic core as shown in this video is remarkable
Wonderful and beautiful explanation of a complex concept. I thank and congratulate the presenter/ speaker and the PBS for making it easy for people with no formal introduction to GR or Black Holes!!
"if anyone could, Gabe could!"
A reference only old school Spacetime Fans will get. I miss Gabe!
Maybe he's coming back :| :| :|
Me too, but I gotta say, he spoke way too fast lol. I like Matt's more relaxed pace.
@@feynstein1004 I always speed Matt up to 1.5x speed.
Leo Staley wow we got a genius over here
@@gianpa gabe is returning in the past
I'd just like to say thank you for putting this series together. If this information was there when I was in school, I didn't soak it up. But I am absolutely enthralled with it now. This channel is like a bucket of water being dumped on my dried-up-sponge of a brain.
_"Coffee gives us a way out."_
I have lived that statement, many a time. 😉
that moment in the morning when your boltzman brain reaches for the simplest solution. n_n
my professor won it this year. so proud of her :)
I remember watching these videos and having absolutely no clue what's being talked about in correlation to my understanding, now, it makes sense, strange how the brain recognises information patterns through repetition, learn the same subjects over and over, learn them in your sleep, either way, you're learning.
"The nobel prize went to black holes, generally speaking"
Wouldn't that be specially speaking?
Special relativity is in the absence of gravity, general relativity is the one with all the holes. Black holes, white holes, worm holes, and donut holes are all the domain of general relativity.
I originally doubted the last one, but after eating several donut holes, it has increased my mass and I generally look like my relatives.
all nobel prizes will end up in a black hole eventually, either way
Well, no. The "specifically" would go into who won them, and what they did, *specifically,* to win the Nobel prize.
This is why I like being around smart peeps. The esoteric jokes.
@Anirban Chakrabarti Isn't pointing out the r/whooosh the peak of meanness possible with that statement
I was hoping you'd mention Conformal Cyclic Cosmology. The Universe not knowing how big it is and not having any time is a mind bending concept but very intriguing.
This, it’s one of these crazy concepts that seems to make sense but I can never make sense of it when I try to think about it... if that makes sense.
I get as far as the universe indefinitely expands, all matter in the universe is ripped apart, and only photons are left. Nothing with any mass remains. No mass = no time and no concept of distance.
That’s about as far as I get. I say that but I don’t even know if my current understanding is even close. Hoping somebody might do a layman’s video of it. Maybe vsauce or something.
Ultimately I’m not even slightly qualified to analyse any theories about the universe so it just boils down to “what sounds right”. And there’s something about CCC that smacks as “that seems to make sense”. Even though it can never make sense to me.
Christ am I still typing? Sorry you had to read this unfiltered thought stream. 🙈
@@EsotericStarWarsRubbish You're almost there. I struggled with the concept as well but there is a way to make sense of it. I'll do my best to attempt to explain the insight given to me by a professional physicist when I asked her about it:
The key is to think about how light experiences time. In short, it doesn't (nor do any other massless particles for that matter). If a photon can't tell the difference between a unit of Planck time, a second or a year, a Planck length, light second and light year are all the same to it. Distance loses meaning. The implication is that a photon would perceive itself not as a single particle, but a line following its null geodesic, going from its origin to its end (e.g. collision, black hole or all the way to infinity etc.). The only thing that the photon knows in some sense are the events in which it has crossed paths with another particle, which look like converging lines. The point of CCC is that given these facts, infinity and the Planck length are physically the same thing for a photon, as long as the angles of the crossing paths are maintained (=conformality). Thus, in a universe filled with nothing but photons, the big bang and the infinite future of the photon universe are physically indistinguishable as long as things remain conformal.
Whether or not any of this is true is hard to tell, as it does assume that both protons and electrons decay. Proton decay might be possible, but electron decay is even less likely (charge conservation violation). Additionally, I don't claim to understand at all how accelerating expansion of the Universe plays into this. One would assume that only parts of the Universe that have even the potential for causal contact can undergo CCC. If certain things recede behind the cosmological horizon, not even a null geodesic will reach them. I don't know if this actually implies that every subsequent aeon in CCC is a lot smaller than the previous one, as each new big bang ends up flinging stuff beyond the cosmological horizon as seen from any given point in the ensuing universe.
@@lexagon9295 oh wow, thanks so much for the detailed response. I’ll need to read up on a lot of the terms you’re using to really make sense of it. Again a mega thank you for your response.
My other question while I have you (sorry pal, shy bairns get nowt 😅) is about this far flung eon being very large and cold, but it’s physically equivalent to a very hot and dense universe which was at the start of the Big Bang.
I guess I can sort of wrangle my head around the idea of the maths: that if there’s no longer a concept of distance then all that spread out stuff might as well be packed all in one point, but... well, you can see my problem. And it certainly doesn’t help when the ceiling of my terminology is “stuff”. 😰
Of all the struggles, that’s the part my brain struggles with most: how that exponential expansion then translates into an infinitesimal point which the next Big Bang then comes from. Though I’m not even sure if my basic understanding of it is even on the right lines!
@@lexagon9295 thanks for that, but the part that gets me is not the scale equivalence, it's how you go from the photon only universe back to a universe with matter. And once you now have matter again, then doesn't scale um, forgive me, matter?
Kurzgesagt and Space Time on the same day? It's a singularity :D
They're both sometimes speculative but Kurzgrsagt is a lot more iffy and woo and incorrect.
@@kypdurron62 Hmm I guess. I still like them tho
I dream a collab
Space Time is better though. There's much less fluff.
Shut up
A simpler, but possibly only entertaining and pleasantly mind twisting explanation is the Time Factor Theory channel.
The fact we have observational proof of black holes is amazing
Yes! My favorite ASMR channel has release another video!
I don’t think this is an asmr channel
@@Kevin.OBrien44 It can be, depending on the viewer. I, for example, am usually watching / listening to these videos before sleeping.
What happens in a region of perfectly empty space?
It doesn't matter.
(Don't all laugh at once)
Empty space is a myth
It doesn't antimatter, either.
There is no empty space. Even the voids in the universe are filled with quantum fluctuations.
"perfectly empty space" cannot contain by definition anything. So also no geodesics, hence no time and no space!
@@fabimre you are contridicticting yourself, empty space = nothing, nothing cannot be space😀
You should absolutely do that on the first day - give a Boltzmann Brain explanation and walk out. And then ten seconds later, walk right back in and begin the actual lecture.
That's one way to make sure the students are paying attention.
Incredible content Matt! Your excellent demonstration of Physics is top quality, as usual. Thank you for your dedicated work, and thank you for bringing such knowledge to the world.
PLEASE do an episode on the Everett-Wheeler Telephone, it sounds so cool
I want one of those phones
Penrose is such a badass. CCC baby!
Thank you for this visual explanation of the Penrose Singularity Theorem. It may indeed be “vague” compared to the mathematical proof, but is much more accessible and gives us non-physicists a better understanding of how GR implies the universe had a beginning, as you go on to explain in the Penrose-Hawking Singularity Theorems.
If null geodesics must terminate within the singularity of a black hole and the same argument applied backwards in time to the Big Bang singularity prevents a “Big Bounce” from having occurred in a cyclic universe, could some form or quantum gravity revive the idea? If we are to be suspicious of singularities and infinities, then what are we to ultimately find in the heart of a black hole or before the Big Bang?
I would be eternally grateful if you guys could do an episode on shape dynamics.
Saw an interview with Penrose where he explains equivalence of big bang and heat death using conformal math tricks. With the geodesics concept showing that time stops at the center of a black hole and the extension that time started at the big bang, it also leads to the possibility that time ends in our universe inside a black hole but possibly starts as a big bang for a new universe. The baby universe concept. But the question could be is the mass that entered the black hole, the limiting factor for all mass and energy in the new universe ? and by extension is our universe also spawned from a much bigger universe's black hole event?
That’s what I’ve always wondered
@@MaxOakland May i ask-around in the commentsection if someone wants somee
scientific watch-suggests? Or does that leave the impression I'm a robot?
@@nenmaster5218 I’ll take some if you’re not a robot
@@MaxOakland I... am... programmed... to say: Affirmative, fellow Human. Lets consume Oxygen and then check out Sci Man Dan, Kurzgesagt, Sci Show, UpisnotJump, Hbomberguy, Professor Dave and Planarwalk.
Well you have to think what mechanism caused the Big Bang in the first place ?😐 and ok a universe dies 😑so who cares ?😐it dies it dies 😑well….it’s not all that simple 😐we can’t fully understand the Big Bang also what is time 🤔any animal born they don’t worry about time 😑they just say it’s about life and death nothing more 😐humans are the only ones who consider time 😑besides how will we know space time will end ?😐and is it a 100% real thing ?😐humans are just part of the universe 😑when we die we loose track of time all together we will think it’s the end 😑in fact anyone can think of the universe is Big Bang ends forever simple 😐thats only Beacuse that’s how our brains work not the universe 😐in fact I have learned their is a possible link between life and death 😐after all before you you were born what do you remember?🤔that’s right nothing 😑and when we die we become nothing 😑others Would say if we had a life before we would remember it but we can’t so their for it’s impossible 😑you say living is impossible 😐your living on a planet right now 😑that seems more like possible more then impossible 😐also you think we will remember this world forever?😐no 😑that’s not how it works 😑because when you die your body decomposes even your brain you will have no memory what so ever 😑you can try all you want but you will not ever know If you had a life before Beacuse your memory or your brain has limits 😑and your brain only has a limited amount of storage😐so their will be no chance you will remember😑in fact when we die we won’t even remember anything from this world 😐the only thing that will remain will be a manifestation of our selfs 😑before you were born you were nothing you live just to be nothing again 😑
"Coffee helps us out here."
Roight. ☕
8:46, Matt having an existential crisis for 1 second
I feel like this is a clickbait title. But penrose is a national treasure so I'm watching.
Same. But I love Penrose so much, I don't care.
This is one of the best episodes yet. Really great job on this ❤️
The single best episode you have ever done. Bravo!
I always start with understanding you Matt, trying to keep up, but i get lost every time. Doesn't make me stop and try tho !!
There are others. You are not alone.
It. Is. Hard.
But gosh, I remember that feeling of finally getting that the speed of light wasn't some magical universal speed limit but rather (and I think more simply) the speed of causality. It was so much easier for me to understand laymen-level physics once I conquered the jargon/semantics they tend to use in the field.
Um, I need to be that person, here. It's not that you "loose" [sic] him, but that *he loses you.* When you can't keep up with what someone is saying, you are the one that gets lost. Not the other way around. Also, "loose" is the opposite of tight, NOT the act of becoming lost. Ever.
@@MaryAnnNytowl thanks, i changed it. Dutch guy who was very tired when he wrote this. 😉
@@RCS-ONE I understand. Heck, I've actually nodded off when typing something, and sometimes actually accidentally posted it. 😄 Not so often on here, usually on FB, but still... a bit embarrassing! 😳
if i was in the army and got to rank general i would definitely change my last name to relativity
Nice
But then wouldn't you break down if you came upon a sufficiently concentrated group of enemies?
Would you mind if I borrowed that joke from you?
Physicists when they encounter infinity "the theory must be incomplete"
Mathematician when they encounter infinity " it is a divergent series" 😂😂
What I see everything around us follows a oscillating bell curve, I liked the idea of universe converging into a singularity and new universe count from it
New universe with new planets and new galaxies and new stars and new lifeforms and new worlds
A small correction not related to the main topic. Latitude is not measured on geodesics. Parallels are not geodesics on the surface of earth with the exception of the equator.
Penrose is incredible. He gets a bad rap because people tend to think he is convinced by his theories, but he's not. He just pushes boundaries (ha!).
Great episode! Keep'em coming. Thanks to SpaceTime, I can keep on learning without obtaining a PhD in physics.
So if I am remembering correctly, there's some balancing act that the universe works out to be topologically flat. The null geodesics always converging in the presence of a gravitational influence combined with gravitational influence existing everywhere would seem to imply that all null geodesics would eventually converge. Do the gravitational influences cancel out to give us apparent flatness at universal scales? Does the limit of gravitational influence to the same rate of transmission as the null geodesics wind up with that effect? Could the flatness be a more fundamental property of the universe than we expect, and the dark energy/cosmological constant being exactly what is needed to balance the equation towards be the result of the system correcting to flatness rather than a separate force that needed a precise constant that otherwise lacks an answer for why it should be what it is? Am I conflating two concepts that don't actually have anything to do with each other?
The answer to your question, is 7.
I don’t quite understand everything from this video. But it’s a great video to watch. It’s fascinating!
Your channel is awesome Dr. Matt
The easiest way to solve an equation is to multiply both sides by zero.
XD
Genius!!!!!
I have seen all 14 million 6 hundred and 4 possibllities and this applies to all numbers
Thats not solving an equation, thats just simplifing it down to 0=0
This was not solving, but erasing.
Excellent episode! I had a question: some physicists call the "consistent histories" interpretation of quantum mechanics "the right way to do Copenhagen". It would be awesome if you could explain why and how it supposedly solves all these issues like the measurement problem.
What PBS showed in this episode is that Roger Penrose really knows what he is talking about.
This was imminently watchable from a visual aspect, more so than the more recent videos.
You've gotta love this channel!
With the loss of access to all particles at the event horizon, is there any speculation of (or use for) a theory where all particles within a black whole return to their probability state? Is there a relationship between collapsing toward a singularity and loosing their ability to collapse their own wave function?
With given time dialation based on gravity, isn't it possible that upon reaching the singularity in a blackhole with what could to us be considered a "large"(safer) singularity, that you could see the end of time or possibly its rebeginning?
Time doesn't exist. It's nothing more than a word used to describe the motion of energy.
Gravitational time dilation (gravity) just means that gravity resists the motion of energy or changes/redirects it
If there is no gravity then an object won't be slowed down.
Today's singularities theorem was the best. I didn't even know such an incredible result existed.
Penrose shows we cannot follow any path further than any end. We can only begin a new path into the same direction.
Awesome as always. Love this channel.
As always, a truly great video 👍😀! I’d like to ask about three things:
1. Relativity theory doesn’t really rule out an absolute, universal time, does it? For example, Antony Valentini in effect says on page 4 of his paper ‘Subquantum Information and Computation’ (arxiv.org/pdf/quant-ph/0203049.pdf) that quantum non-equilibrium may allow sending signals in an eyeblink through entanglement, and that this would define a preferred reference-frame whose clock measures absolute time.
2. I believe that it must be true that the past, and at at least all possible futures, are equally real as the present, and that the flow of time is due to presentness moving along that fourth dimension. However, what time passes as the physical present moves through physical time? After all, movement needs time. The same can be asked about the second and all higher time dimensions, leading to an endless regress. In his books, such as ‘An Experiment with Time’ (www.fadedpage.com/showbook.php?pid=20181016) and ‘The Serial Universe’ (archive.org/details/serialuniverse032783mbp), John William Dunne uses this argument to show that there must be infinitely many time-dimensions one after the other. John M. E. McTaggart likewise realized that true time must be regressive in nature, as he explains in his work ‘The Unreality of Time’ (en.wikisource.org/wiki/The_Unreality_of_Time). But where Dunne applies modus ponens to show that there must be an infinite time regress, McTaggart applies modus tollens to conclude that time is unreal.
3. Why is only materialism pitted against solipsism in the before-last video? I myself, for instance, believe in an external world (though I’m not 100% sure), but I’m certainly not a materialist. Rather, I’m a platonist, and I see modern physics corroborating my arguments for everything being based on information and abstract things.
What are the beliefs of a platonist? First time I heard the term.
Also, as far as I am aware due to the undetermined state of an entangled pair, the determined state via observation is inherently random and unpredictable (according to our current understanding of QM), so you can't meaningfully communicate, you would just know you got the opposite of whatever the other side got. This is why entanglement doesn't inherently break relativity, the two sides don't actually communicate so the speed of causality is preserved.
@@ThatCrazyKid0007 A platonist (see e.g. plato.stanford.edu/entries/platonism/) is someone who is consciously and quite clearly aware of abstract things as such and their realness and existence. Among the abstract entities are numbers, functions, sets, properties (including abstractness, thinghood, and propertihood), relationships, propositions, states-of-affairs, and of course (Platonic) Shapes (Forms, Ideas; see e.g. en.wikipedia.org/wiki/Theory_of_forms).
Regarding entanglement, according to Antony Valentini (see e.g. arxiv.org/pdf/quant-ph/0203049.pdf), who is a follower of pilot wave theory, quantum randomness isn’t true randomness, but only a consequence of quantum equilibrium. In a similar way to the way in which thermal equilibrium renders energy useless for doing work, quantum equilibrium makes entanglement useless for instantaneous communication. However, just as there is something inherently work-like about energy, there is something inherently instantaneous and not-local about entanglement, betraying its inner ability to allow communication in an eyeblink. This ability can only be made use of if there is a state of quantum not-equilibrium (see e.g. en.wikipedia.org/wiki/Quantum_non-equilibrium). So according to Valentini - if I get him right -, instantaneous sending of signals through entanglement is possible in principle and thus defines an absolute time. How does this violate relativity? It only means that there is a preferred frame of reference, doesn’t it?
@@TristanLaguz Thanks for the detailed response. So if I understand correctly, platonism is basically a belief that abstract things exist independently in the physical reality?
As for entanglement, from my understanding of Special Relativity, it does not mean there is an absolute reference frame, it means the entire theory falls apart. Instantaneous communication would imply that the speed of causality is infinite, which would mean you cannot even form a reference frame at all. In General Relativity, going faster than the speed of causality means you are traveling back in time from the perspective of the rest of the observers. If it's instantaneous, it essentially suggests a communication back in time. It's quite a big leap, which is why we are skeptical of entanglement so much.
A more likely case in my opinion is that the entangled particles are always in sync with each other until disturbed, meaning there is no instantaneous communication between the pair. When you measure them and get opposite spins, to me at least it sounds more sensible that the spins are always opposite to begin with in any direction you'd try to measure. Now they say local variables are ruled out, but a global phase difference between the pair could also be an explanation. However I am not a physicist, so maybe that isn't a valid explanation either.
@@ThatCrazyKid0007 Actually, the platonist doesn’t believe that abstract things exist in the physical reality. After all, abstract things are by definition non-spatial, not-time-ly, not-physical, and not mental. Hence, they don’t exist in the physical reality or in the mind, and they don’t exist anywhere or anywhen. They simply are. For instance, the number 3 just exists and is real; it has no spatial or temporal location, and it certainly doesn’t exist in the physical or the mental reality.
In reality, the platonist is clearly aware of the abstract world as an independent reality, which is distinct from both the mental and the physical reality and at least as fundamental as either. This first, abstract realm is what the mental realm and the physical one are built upon. According to my specific theory, two very weighty and closely linked realities are the abstract reality and the informational one, and the physical and the mental reality are parts of the informational reality. Minds, fields, and many other things are abstract things, though, according to my philosophy. So mindly reality and physical reality emerge from the abstract world and the realm of information according to my worldview.
Concerning entanglement, you’re right that something global must be at work, and that’s exactly what pilot wave theory says, for it’s a not-local theory. You’re also right that the spins are always opposite to each other. But the global phase difference is a means of instantaneous communication, at least on a fundamental level, isn’t it? It just happens that the probabilities are always such that no useful sending of info is possible, right? Now I’m not saying that Valentini is right, but I find his ideas, and broadly some ideas of pilot wave theory, especially quantum non-equilibrium, very interesting and worth learning about.
As for the relationship between instantaneous sending and Relativity, my understanding is that according to pilot wave theory, we have the following: There is a preferred frame of reference (PFR or PRF) whose clock measures the absolute, one true time. An event F can influence and event U if and only if U lies ahead of F in time according to the preferred reference frame (where the time difference can be infinitely small, so to speak). Entanglement allows signalling which is instantaneous in the PRF. It may look like finite-speed FTL communication in some other reference frame and like sending info back in time in yet another, but that’s no problem. What matters is how it looks in the PRF, and there, it’s endlessly fast sending. Since you can’t go back in time according to the PRF’s clock, there’s no violation of causality. To travel from an event Þ to another event F in the past light-cone of F with the help of FTL, you have to go faster than light to some event U a space-like space-time interval away from both F and Þ, and then again fly FTL from U to F, I think. However, that’s not possible in pilot wave theory because at least one of the journeys would involve going back in time according to the PRF, which isn’t possible. So how does Relativity break down?
Also, how does an endless speed of causality imply that you can’t have reference-frames? For one, the above shows, according to my opinion, that we can have infinitely fast causation in Relativity if there’s a PFR. Secondly, Newtonian mechanics allows infinitely fast about-bringing and still works perfectly with reference frames.
@@hyperduality2838 What is dual to duality itself, and what's the well of the duality of duality and its dual?
I wonder if we'll see the merger of GR and QT in our lifetime? Imagine how exciting it would be!
that would be amazing!!!
i just wrote a comment:
"even though black holes have a point of infinite density/gravitational pull, they may still look like smaller neutron stars once you cross the event horizon. just as there's a planck length, there's also a planck energy, which is equivalent to mass in this case. so you can only crunch so much material in one cubic planck length before it can't hold any more energy/matter. at the center might be infinite gravity, but it could be cancelled out by infinite cubic planck length density, then you can maybe cancel the infinities (idk, i know some infinities are larger than others) but it makes sense in my head that a black hole may not be a point of infinite curvature (i.e. infinitely small), but actually rather large on a human scale, just like white/red dwarfs or neutron stars. hmmmm"
and i think it's relevant to your point. it may depend on where you cancel the infinities. maybe a lot of the math has to go back to the beginning and find different solutions.
but i think if we can figure out the inside of black holes, we would be able to merge GR and QT, though realistically it would probably happen the other way around. but really fun to think about
There needs to be more awareness of the GRQT community.
My bet is on the name "Quantum Relativity" xD
@@patrickaycock3655 GRQT+
@@sagnorm1863 I am a GRQT+ ally.
I think "Dark Star" is better name than "Black Hole" for the Singularity first mentioned by Laplace and Mitchell.
No way.
I'm a bit unsure if calling it a "singularity" is correct. If a dark star is merely one whose surface escape velocity exceeds the speed of light, then it need not to have "infinite" density, per se. I'm not sure if they ever mentioned that such a star would undergo a collapse that would have infinite density.
What do you think?
Nah All hail Dark Helmet
I think a shady ball is a nice name
... Its all new to me, but I'm realizing, at this late date, that our 'school systems' have been putting out 'slim pickings' with regards to teaching physics, when it should be a most necessary subject, 'Must Have' subject, for I can see that our future progress as a civilization, will be dependent on it. I am so grateful for this channel, for tho the material deep, previously unknown to me and sound like 'French' to me, to top it all off, (I don't speak French) I can grasp a better sense of what some of these principle s or theories are, much better than from material on other channels!! So thank you very much, ummm.. Slow down a bit... You talk as fast as me, lol, keep safe + stay healthy.
XxxOoo
Maggie
I say without irony, Brody Rao is my hero. Space Time is the most intellectually nutritious thing I watch and I'm grateful for Rao's generosity.
What happens to the singularity of a black hole if that black hole is rotating on all 3 principal axis or even just two?
a ring
rotation on multiple axes can always be described as a single vector... it ends up being a combination of the inputs
then it's a ring or a sphere surface
the geodesic graph is a visual aid, a black hole isn't an infinitely long pointy cone in reality
ayo wassup sk1er
I sometimes wonder if it's possible that the "singularity" isn't, in fact, *infinitely* small, but that matter that once composed the star has some lesser state it can collapse down to that is unobservable to us due to the event horizon. That is to say, I wonder if the singularity of any given black hole could be the size of, say, a proton or even a quark... something insanely small, but still quantifiable.
Hence the planck star theory. It can't be observed directly, but it can be used to test theories and simulations.
It's silly to assume that there is a singularity.
A blackhole could collapse to half it's size before light couldn't escape... we don't know it's physical size.
The reason why light can't escape is because the gravity is too strong... the event horizon is just where that ends... other than it's barycenter that creates galaxies and the reason why things orbit regardless of speed.
If time or space actually existed we could create counter/anti/reverse spacetime to gently exit or enter a blackhole.
Lets rewind the temporal dimension back to a moment before the year 2020 A.D.
With full knowledge of the future or not? How do you know we didn't already do it? Ughh, this space-time suff!
November 2019?
TYVM for this, Roger Penrose is my very favorite , most beloved Science person , there is never a dull moment with that old brainiac .
Penrose's name is just everywhere, from the idea of Pentagonal Tessilation to this.
Got panicked when I read "The End of Space Time"... Keep us dreaming Matt!
Its happening, everyone stay calm!
"What do we do?!"
Heya. Love the channel and would adore it if you could answer a question I have about the many-worlds interpretation of quantum mechanics the nature of time. If it could be described that different areas of reality have multiple possible states that are all just as real, and as more quantum "decisions" are made they reproduce, could this also work in reverse? If these quantum systems are deterministic then could that result in a shared future for multiple states?
In other words: if certain outcomes can be reached through more than one previous state, is it possible for the past of a particular state to become undetermined? The past itself becoming multiple possibilities like any other quantum state in superposition? If this is true, would a universe with maximal entropy be a single final state with an unthinkable number of pasts all just as real behind it?
Got to love the Dude Where's My Car reference Zoltan
God, I love this channel so much. I watched one video that was recommended to me, didn't understand something, heard in the video that it was going to be discussed in the next video - that video was quite old, so I clicked on the channel videos.
And oh my god, I want to watch ALL OF THEM. ALL THE VIDEOS ARE INTERESTING
A wise person once told me if your math predicts infinite anything, it’s probably wrong.
That is the point of the theorem.
Long before I knew a bit of physics always thought that the word infinity was just into religion but never think it was well asepted in science, to me they must be wrong, they say the universe is infinite but Penrose says is ok if we compress it to a point.
I find it sad that Stephen Hawkins didn't get the Nobel prize, only if he lived for 2 more years.
Stephfen Hawkings*
@@robertstevensii4018 Stepfen Hawkings*
********Stephen Hawking
His name is Stephen Hawking (no S) 🤦🏼♀️
@@robertstevensii4018 No it is Steffen Hawkings
I could never be a scientist. At least not one that studies anything like this. I love watching these videos (and I'm pretty sure I've learned way more than I ever learned in school!) but the 10-20 minute videos are about all my paranoid anxiety-riddled mind can handle. Just imagining a *job* consisting of constantly thinking about singularity, black holes, the beginning of everything and the end of spacetime... Goodness, no thanks. My mind has enough trouble just dealing with my own little existence here on Earth!
Its mostly math tbh. My boys get incredibly excited about solving math problems and looking at numbers on sensors and other machines. True nerds. Its not like they are looking at animations of nebulas or whatever that we see online.
Another great episode! Keep making them, I'll keep liking them!
The basics of this lesson is black holes are naturally negative things, as they appear. The mention of limit measures is also included. I liked the mention of two separate types of black holes and noticed they are not opposite, it's a fun vid.
Thank you for acknowledging that when GR predicts something crazy - it probably means GR has broken down there and we have more to learn, *not* that the crazy outcome is reality. As you said - usually infinities are a sign we don't have it quite right, and it seems far more acceptable to me that with current evidence, "GR doesn't adequately describe events inside the event horizon" is a better explanation than "Every black hole contains a real singularity". They may - but GR isn't proof of that.
We can thank quantum mechanics for its wonky effects at such small scales and it fundamentally disagreeing with GR at that scale. If whenever we find a quantum theory of gravity we find it still predicts these singularities, we'll be in a bit of a pickle :D
3 things you will never reach
infinity
singularity
you starting to change your life
👏🏾
"What in our universe is perfectly spherical or smooth?" A cow. Game, set, match doubters.
Dees nutz!
Another Sean Carroll fan? That is who I learned about spherical cows from.
@@paulperkins1615 no, I knew about it years ago. My HS physics teacher made the joke in the last century. ;)
A perfect circle en.wikipedia.org/wiki/A_Perfect_Circle
Due to a cow's digestive tract, they're actually topographically equivalent to a torus.
Been waiting for you to do your take on it.
Love Sir Roger, wow, his take on a photons' view of the universe. Just brilliant.
Prof Penrose is a philosopher.
And a well physics professor.
If information can truly be destroyed or obscured, is determinism even possible? If determinism depends on every prior state in the universe, and some of those states are "missing" or otherwise somehow unaccounted for, then isn't there some fundamental randomness, at least from our point of view?
And that's exactly one of the problems physicists are trying to solve with quantum gravity, cause without it black holes can truly destroy information, which shouldn't be possible. That's called a black hole information paradox
Seems so, but our point of view seems pretty trivial at this point.
Not really from my understanding. Information loss just means information becomes unavailable to the rest of the system, what happens to it past the causal discontinuity has no effect on the rest of the system anymore since no causal link from inside the disconnected system can be made to the rest of the system.
Since all information in the universe is causally linked to the CMB, there is no reason the information cannot diverge from each other in a way that it no longer available to each other.
Think of it as a branching tree. Branch 1 is unavailable to branch 2 for any possible interaction, but they are still coming off the same trunk.
@@ThatCrazyKid0007 if that's the case, though, the information isn't lost. If you can keep stepping back and causally linking events all the way to the CMB, then I agree. If the information is truly lost, though, there would be a break in the causal chain somewhere. I guess since we have the CMB maybe you're right. We can always infer the intermediary steps, but if that were the case than Penrose's theorem only proves that sometimes it can be harder to discern information.
@@generalZee If the information is destroyed at the end of the chain, what's the problem exactly? There is nothing to suggest that determinism is opposed to a finite causal chain. If there really are singularities like ones described by GR, then all it really means is that there is a finite set of finite length causal chains that all had the same root. Again, like a branching tree of events.
The problem with event horizons and what the information paradox is really about is not that the information is annihilated per se, it's that you can't traverse the causal chain in both ways. Think of it as a continuous function with a point of discontinuity. You still have a function that describes the entire life cycle of a particle (and its information alongside it), it's just that when you go from the left to the discontinuity you have no idea what is on the other side, the same is true from the other side going right.
Quantum mechanics demand continuity so this is a big problem for the theory (what is meant by preservation of information), but not really for determinism itself. It just says you have a transition that is not predictable from either side inside the different portions of the system, but in a 4D block universe you could easily see the entire life cycle.
I never want to hear that phrase "the end of space time"
I was worried it meant the end of this channel!
Why? Life is suffering
My cockatiel seemed strangely interested in watching this.
His name is Newton, by the way.
🌟 - for the smartest bird around
@@patrickaycock3655
Appreciated, but I'm not too sure about that - he eats his own poop.
@@CloudsGirl7 🤣
@@CloudsGirl7 Hmm. Must test hypothesis.
Yeah I caught that too.
One of the most interesting episodes ive seen in a while
Kind of a fun fact: Null geodesics have paths related to the golden ratio! (There's a really cool paper by Cruz, Olivares, and Villanueva that explains it.)
Same as the PI the PHI is all over.
"I'm gonna go get the papers, get the papers"
Just don't go looking for them in meat freezers
roll it up pass it down
jimmy twotimes
Goodfellas reference?
Goodfellas reference, my favourite movie.
The biggest Question in the universe:
does PBS stand for Peanut Butter Sandwich??
Depends. PBC? Does one grab peanuts 🥜🥜 by chance, or is it because intelligent design in the genetic code that has already programmed this ∆ events that unfold with evolution of life in our universe.
I predict a Grand Unified Theory for the peanut butter sandwich. I feel it in my gut.