Favorite line in the video lollll why are Aussies the best content creators on the planet?? Between this and the channel I Did a Thing, I’ve learned more about nature and life and humor than anywhere else. And Tame Impala? We really should celebrate Australia in the U.S. more, heck aren’t our countries almost the same size?
This channel re kindled my love of physics and learning almost a year ago. I'm now back in education studying physics and loving it. Thanks PBS spacetime and an especially huge thanks to matt! keep up the awesome work!
@@impalabeeper It’s a reference to Ivan Pavlov, the Russian psychologist who taught dogs to salivate at the sound of a bell. He did this by giving the dogs a treat every time he rang a bell, causing them to associate the sound of the bell with receiving food. After hearing so many episodes of this series end with “...of Spacetime” (or some variant), I heard the host say the phrase in the middle of the episode and assumed the episode had ended, just like a dog salivating at the sound of a bell. Does that make sense? :)
It sounds like a line from Hitchiker's Guide to the Galaxy but I'm not sure. That is funny, but let me take you seriously for a minute. Would you need a stack? Wouldn't the state of each particle or voxel be a simple iterative process like the game of life? Seems like one while loop would do the job. There might be subroutines, but you'd need to have some kind of recursive process for that to happen.... maybe Feynman diagrams? Like, figuring out all the possible virtual particle interactions. Hmmm, hehe.
What if quantum mechanics is just an artifact of compression to make it easier to compute macroscopic physics without needing as many resources as if you were actually going to try simulating each particle down to each planck-voxel in phase-space. If we were to build our own universe simulation, how much would implementing quantum mechanical phenomena help in decreasing the required computational load? Indulging in the Simulation hypothesis for a moment: Humanity's exploration of physics appears dangerously analogous to reverse engineering unknown computer hardware. I think we're becoming aware of things that weren't expected to be noticable. Who knows, we could eventually come across a physics glitch that we could exploit for FTL communication or something.
I shit you not, trying to develop a distributed physics engine for a game, it is VERY UNCANNY how many phenomena of actual physics are conducive to unrestricted parallelization. There are global speed limits so that in a finite time the cluster can gather all causal events in your light cone before deciding what happens to you next... there is the heisenberg uncertainty principle so you don’t have to waste cpu cycles resolving exact details of every aspect of particles for an observer... Quantum tunneling (or its cause, the wave function) is a lazy but efficient work around to avoid resolving newtonian collision on every scale of spacetime.... In higher energy (higher gravity) regions of space, time runs slower, because it is more computationally intensive than low energy areas of space... Relativity of spacetime means physics is stable to compute inside massive inertial bodies, even if outwardly the body is at a high velocity compared to a different body (no global notion of velocity). I bet there are even more I havent discovered yet Edit: Quantization of matter and energy, in contrast with infinitely and infinitesimally continuous and differential space and particles. If the universe was a living and moving and breathing fractal with no quantization (no 'minimum' metric for various physical properties, the so called plank metrics), then this would lean slightly in opposition to the universe being a simulation, but since everything is quantized, this aspect actually leans slightly in favor of the the universe being a simulation.
Sorry, I don't understand how the encryption and fuzzing relate? It sounds like you're describing compression, but even then I'm not quite sure how that related to the seemingly random nature of quantum mechanics. I understand that really good compression will resemble randomness (as would encryption), but I don't understand how that would drive quantum mechanics.
I admire you. (and your viewers who interact) Intelligent, well spoken, etc. This subject is beyond my intellect, but I do understand the basics of what you are presenting. I've always been fascinated by this, and enjoy watching the advancement of science and its realisation of space time. We've come a long way, and hopefully a long way to go. Thanks sooo much for your show and the effort you put in to it.
Rita Eric Interesting perspective. One problem, though: aren't we humans the universe's eyes and brains with respect to RUclips observations? I'm sure there are much higher novelties in the social media genre out there in some distant spot in the universe, witnessed by vastly superior intelligence than our own. But where is this info stored? And will it get erased? If so, what then?
Did he just assume the universes information? Cant beleive the white privileged male went there. That’s it I’m starting a movement I’m with everything.
Who knows? Maybe the information defining our universe exist outside of it. Example : If you simulate a world using your PC, the information about the world is contained on a Hard Drive, RAM etc. If there was intelligent beings in that simulation, they could not directly observe there is a PC at all. They would believe the information is contained within the Universe too.
i can see the point and it is a very good way of thinking about the programing to keep it fast and lower mass. but i think that would actually work but if are we trying to compute every Planck time from start to end or just in the moment because if its just right now we can over lay existing information into the programing to give reference that could take less computational power and if they are at that point very likely an AI running in it could create all the deviations itself at the start and just keep it stable running diagnostics or shut it off to more effectively use the area.
Is the backup server located in an other universe? I mean, it's not smart to have a backup of your hard drive on your hard drive... That would kind-of defeat the purpose of backing it up...
I look forward to these episodes more than pretty much anything. It helps keep me going some days. Thank you ever so much, as sincerely as I can convey in a YT comment. This is extremely needed; Darkest timeline and all that...
Surprisingly high if we consider only biological systems and we have an open mind for what porn is (for example is animal nudity "porn"?) But surprisingly low considering most systems are non-biological. Now let's wait for "black hole porn" (no, not that kind of "black hole", I mean the one physicists deal with professionally), if that kind of nerdy porn ever happens, then it'll be 100% and the word "porn" would lose all meaning.
Thank you, thank you for keeping the background music/sound design down to an almost imperceptible level, so that we can hear Matt's amazing content! Other RUclipsrs, please take note....
This idea of a practical computing device based on a black hole is a fascinating science-fiction concept. A laptop with a kugelblitz inside would however be rather heavy.
I think it would just be unable to store more info beyond a certain point (unless it like, got more material in order to store more info, in which case it might collapse) This also implies that, unless it keeps getting bigger and bigger without bound(though possibly incredibly slowly), that its states will eventually repeat, so insofar as one's life consists of one's experiences, then assuming that all one's experiences in this world correspond to physical states, the sum total of the thing's experiences, and therefore its life, must be finite, and that therefore it must be mortal. Unless the Bekenstein bound somehow turns out to be incorrect, or there is some way to grow in size without bound, then if there is any hope for immortality, it must come from outside this world. "And the last enemy to be destroyed is death." 1 Corinthians 15:26
If natural selection is able to apply exponentially increasing selection pressures on it (natural selection of ideas), and there is enough lower energy states to feed it's growing complexity (exploiting faster interactions at lower cost). You could get a entropy hole. It wouldn't be able to stop either because if one part of the brain gets "Lazy" the other parts will cannibalize it, or leave it behind as it shrinks to lower energy states. If you can divide energy to infinity, then it could live forever, relative to it's perspective, but relative to our perspective... we would see it disappear, and maybe even destabilizing space, by causing a pressure differential in the vacuum.
PBS space-time is not the channel we deserve, but we the one we really need. If anyone is reading this archived comment after 100 years. Ssup? How's your house boat? There was something solid like the floors you stand on in our times...it was called land.
As the universe expands, its volume increases faster than its surface area. Since the amount of information is limited by the surface area, does this mean that the amount of information that can be contained in a given volume of space (i.e. a cubic lightyear for example) decreases over the lifetime of the universe, or is that just an average? Also, is there a relationship between entropy and dark energy? Since entropy increases over time, which requires more information to describe the macro-state of the universe and more information in turn means the universe should need a larger surface area to store all that information, which in turn requires an increase in its volume, it seems there might be some interaction. To ask in a different way, does the acceleration of the expansion of the universe follow the square cube law?
And I'm not sure if we ever got an adequate explanation as to why expansion of space only seems to occur in voids between galaxies and not evenly across all space. Am I mistaken that the expanse between here and the moon is comprised of the same "space" that is expanding? I get that baryonic matter is gravitationaly bound but surely we could observe Lambda locally and not just via the redshift of distant galaxies. No?
To add to this question, if information/entropy really is "imprinted" on the surface area of the universe, then it follows that since the volume of the universe increases faster than its surface area, information density must also increase along with the expansion of the universe. Does there come a point at which the information density of the universe exceeds the Bekenstein limit and the universe becomes a black hole -- or is this prevented by conservation of energy? To put it another way, does expansion create new information, or is the information content of the universe constant (ignoring transient loss of energy to black holes and the like)?
Mercurius314 "more information in turn means the universe should need a larger surface area to store all that information" - not so. As is explained in this video, the informational capacity of the existing volume is far from being exhausted. So there is plenty of room for entropy growth in the existing volume (and associated surface area). But I wonder what would happen if most galaxies were consumed by their central black holes. Could the cumulative entropy of the resulting black holes exceed the maximum permissible entropy of the Universe?
My understanding is that it is all space, earth-moon or even the atoms in your fingernails. But since it's fractional small distances have a small, perhaps immeasurably small, increase in absolute terms.
Question: If time and space started with the big bang. How would other universes measure our time? The same way we measure the time of a book, as a fixed beginning middle and end that we exist outside of?
7.5 million years, more or less. However, since we are part of that simulation, we can't assume that our time runs in the same frame of reference as Deep Thought. 7.5 million years could end up being several eternities to us.
Anyone attempting the challenge question should also read the hitchhiker's guide to the galaxy before submitting. It was poking fun with some of these concepts back in 1985. Also I recommend learning about coding theory. As an EE grad student I took a class called "Information Theory" and it was life changing. Without having to do the math heavy statistics I'd say if you can find someplace online that teaches how to hand encode and decode huffman and lempel-ziv (and you can actually do them) you're halfway there. The other half is shannon's source coding theorem, the law of large numbers, and a few other stats laws I forget now :x Of all of those things the most important concept is shannon's source coding theorem which is intuitive and can be taught easily because it's so easy to demonstrate. Take an uncompressed bitmap image of noise, just randomly placed intensity values, and put it in a zip archive. Take another uncompressed bitmap of the same size but only one color, and put it in a zip archive. No information was lost in compression because you can extract the exact same image that you put in. The image of noise will be the same size (maybe a few bits larger) than the uncompressed version but the image of just one color will be tiny. Lastly I have a fond memory of a homework problem from that class: There are two weathermen in a city that only report if it will be sunny or cloudy on a given day. One weatherman is right half of the time while the other is right a quarter of the time. Which one gives more information about the weather? Use the definition of entropy to prove it.
I am curious good sir, is there any form of compression that can reliably reduce a dataset of x^3 bytes to an output of X^2 or a multiple thereof? You sound like the person to ask.
Use universe density of mass or something like elementary particle to calculation the universe "Effective density" gave by the equation: ρ=3H^2/8πG Because in the video , you say "if niverse fully filled the at the moment the universe reached its informational limit you would immediately become a black hole ", so use the same logic , if we use cosmic radius multiply "Effective density" , then we get the radius of black hole computer. R=universe radius x effective density =(138ly)(3H^2/8πG) =(138ly)(0.85×10−26) =(117.3 x 10^-26) This is almost Approaching to 0 t=Q/V(black hole computer sarface area) Q:Calculated amount=(4/3)πρ(c/H)^3 t:time But i won't calculate the t , so suppose the t=138^9 year so the v=(4/3)πρ(c/H)^3/138^9 year but that still does not exist, too unreasonable
Assuming 1 bit per elementary particle is nonsense: to describe any single, say, electron, you'd need a lot of information: 1. location (probability of location), which alone takes a huge amount of bits if described at universal scale in binary form) 2. type of field: the fact that it is an electron and not a Z boson or a charm quark must be informed, this again takes a substantial amount of bits because there are 24 QFT fields (at least), in some cases with more than just one bit of possible info: electric charge needs two bits because it can be positive (10), negative (01) or nonexistent/neutral/empty (00), color charge needs three bits (we can compress the anticolor of gluons but not the anticolor of antiquarks), etc. 3. particulars of the particle such as spin (another bit), energy state (probably several bits), etc. That basically makes the amount of info at every particle needing five bits at least (if what I read about 61 "fields" with max. info is correct), PLUS you also need to describe location in space and time (the matrix is also information!), which at the Plank scale seems to require lots of bits (your usage of base 10 numbers does not help here, could you use hexadecimal instead?, in any case LOTS). The only question remaining open for me is that, because particles are much larger than the plank unit of space (uncertainly so but statistically they are), IF there is enough empty space (or quasi-empty space) to compensate the scalation of figures. A problem I can't underline enough is that you can't just code the universe in *space* but you also need to do so *in time*, else you'd only get a snapshot with no causality attached, and that seems even more daunting and more bit-intense (a photon can be in many plankspaces but "ticks" at planktime units AFAIK).
How does it matter, Michael? I can understand that phase space formulation would allow to compress some of the info but only for as long as no interaction happens (example: a photon traveling in ideal vacuum). But interactions do happen all the time, and they are chaotic in nature (more so considering quantum uncertainty).
The more I look at this, the more confused I get. It made perfect sense at first, but now ... . At any rate, it wasn't on the curriculum when I was in school, so I'm having to play catch-up fast. Perhaps, and this is just a guess, it has to do with the difference between classical and quantum information. Or perhaps not.
Can't say. I also assume I'm missing something important, that's why I posted my objections: not to win any argument but to see if someone could win it against me and teach me something.
Luis Aldamiz Ok, assume that you don't need 1 bit, but 1000 bits to describe an elementary particle. What's the effect ? Instead of 10⁹⁰ you now have 10⁹³.bits. Do you feel better ? That's exactly what he meant about rounding and ignoring small disturbances in the presence of larger numbers. 10⁹³ is of course 1000 times bigger than 10⁹⁰, but relative to 10¹²⁴ its still pretty irrelevant and can therefore be neglected in first approximation.
I've been to arrogant to consider watching videos about space and time. I thought I already knew everything there was to know, and I think I was afraid of learning more. All the titles just looked like clickbait, and I didn't think I'd gain anything real from them. Or maybe I was afraid I would. My roommate convinced me to watch though, and now I think I'll continue to watch every video you guys make. I might even go back and take notes.
So... has the universe ever been in a state of "too much information in too little space"? Particularly during the big bang? Is this what we mean when we say that the universe was too hot for some particles to form? ie was the universe too dense in information to allow all the required quantum states for classical matter until it expanded?
It's a silly question really, since here "information" means something without any material substance, even though they don't say it straight. If a thing doesn't have any dimensions, we can't talk about it's density. This documentary is just pseudoscience. There's no scientific basis to argue that the material universe is fundamentally made of something non-material. Information, as we know it, is always in some material form or another, whether it's computer data or genetic information. In essence, the model proposed here is a modern day version of Plato's world of ideas = idealism.
bormisha, information can be both abstract and concrete. There's concrete information like computer data, existing in electronic circuits. Abstractions are a product of human mind. In quantum physics for example, abtractions help scientists to make sense of highly complex processes. However, abstractions don't exist as such, like you said, let alone form the basis of reality. Trying to put these hypothetical cosmic "bits" into a measurable form is like chasing ghosts, pure nonsense. Professor O'Dowd here attempts to capture the ghosts into two-dimensional boxes. Furthermore, he doesn't even try to explain what space itself would be, considering his assumption that all reality is "informational". Any credible scientist shouldn't waste time building metaphysical models like these. We already have plenty of mysteries in the cosmos waiting to be solved.
I'm a bit confused by thinking that the estimate of storing each particle as a data point is anywhere close to accurate: You're assuming that 1 particle = 1 bit of information ... but you can't even begin to describe even a single particle with just 1 bit of information. Even something as basic as 'what sort of particle is it?' is going to take several bits. (6 bits for particle type alone, assuming each of the 38 fundamental particles is assigned a binary number to represent it.) And that's not to mention things like location, energy level, momentum, direction of movement... I'm sure that a well-crafted storage scheme could minimize the size of that fairly well, but it's still going to be far more than 1 bit per particle. It could take hundreds or thousands of bits to describe a single particle, depending on how fine-grained your measurements of things like position and velocity are going to be. Is there even any limit whatsoever to how small the differences in momentum between two particles can be? Each particle might require enormous amounts of data to describe that accurately.) Along the same lines, there's a similar problem with assuming 1 bit per Planck volume -- Suppose the bit for a given volume is '1' ... what does that mean? What would it mean if that value is '0'? Does a '1' mean that there's an up quark there? Or is it an electron? Maybe a gluon? Or a photon? If it's a photon, what direction is it traveling, and what's its wavelength? There can be far more information in that Planck volume than could be described with a single bit of information. Not trying to nit-pick, but the 1-bit assumption seems to be an enormous assumption to just be throwing around with no explanation.
O Ocalhoun Ok, assume that you don't need 1 bit, but 1000 bits to describe an elementary particle. What's the effect ? Instead of 10⁹⁰ you now have 10⁹³.bits. Do you feel better ? That's exactly what he meant about rounding and ignoring small disturbances in the presence of larger numbers. 10⁹³ is of course 1000 times bigger than 10⁹⁰, but relative to 10¹²⁴ its still pretty irrelevant and can therefore be neglected in first approximation.
I think you missed the point. He’s just simplifying to get the message right. If it takes 1 bit or 1MB it’s irrelevant for the topic and to the magnitudes at discussion (just add a few more units to the exponent)
String theory assumes particles are vibrating on the same string, since all those variables you mentioned then start to break apart, a single bit can describe a single particle as the bit is also a string
According to group theory, you can describe an elementary particle with basically two numbers, mass and spin - but you're right, this whole video is more of an analogy than a real hard argument. Truth is, the number of bits/unit volume is just the computation of the entropy available - and since BHs (supposedly) contain most of the entropy of the Cosmos, that's what this all boils down to. If there were no BHs, we'd go to the next best thing, the CMB, and so on. Also, bear in mind the Bekenstein bound is not so much an statement on the limit of information admissible in the Cosmos as a _consequence_ of our current understanding of gravitational collapse
7:11 For me that's the key to understanding the "Holographic Principle": - no need to know the positions of particles inside a BH, so the Info content might fit on its Surface, - especially as the BH's Surface increases by 1 Planck Area each time it absorbs a Photon Mass-Energy [cf. Susskind, The Black Hole War]
It would appear that we are NOT inside a black hole since Matt pointed out previously that inside a black hole space and time swap meaning and all you have inside the black hole is an inevitable future at the singularity (unless the singularity is the "Great Attractor"). In that case, what would happen if the super massive black hole at the center of our galaxy hits the singularity of our entire universe (assuming we are inside a black hole and not just a holographic non-black-hole universe?
Awesome idea. I don’t think we would hit the singularity though if it were the great attractor. We would just orbit it like everything else in the universe does. I saw a documentary a while back where many well known physicists used to believe the universe was shaped like a donut or a figure eight and that all the matter in it was orbiting something at the center then looping back around. Awesome stuff.
Radioactive decay isn't entirely random. It can be affected by proximity to the sun. This was noted by a team of physicists from Purdue and Stanford. They were trying to use radioactive decay to generate random numbers, but noticed what appeared to be "seasonal" changes in decay rates. These changes were significant and although much more work needs to be done on the subject, it seems that as the earth paths closer to the sun it affects the decay of particles. I'm thinking we just discovered a way to detect gravitons, maybe?
To simulate the Universe, you don't have to simulate it all at once. Using procedural generation, the particles in some region of space would only be simulated when they were actually looked at. The only risk would be that many particles simulated together might behave differently than you'd expect from studying single particles. So for example the simulation of multiple particles through two small slits could calculate a wave pattern, but the detailed simulation of single particles would give a different pattern, due to the level of detail of the simulation.
Does the Bakenstein bound also put a limit to the density of the universe or to the density of a given region? Like, as the radius increses, the volume increses by r^3 and the maximum number of particles increases by r^2, the limit density should be proportional to r^(2/3)?
Yes, the maximum density is that of a black hole. What this means is that larger black holes are less dense than smaller ones. The one at the center of our galaxy for example is only about as dense as lead and far less dense than a small neutron star.
Spacetime episodes contain so much information, there is little left for everyone else in the universe. Guys, stop hogging everything to Yourself! Share a bit... wait...
So all the information in our local area of the multiverse is contained on the surface boundary of the universe, but doesn’t the surface area grow over time, and doesn’t the surface area of every region of the universe outside our particle horizon also grow faster than the speed of light?
All of the observable universe is an Imaginary black hole for the Hole Universe if i may say that....Its Event horizon its defined by the speed of light. It doesnt matter where you are in the Universe ....you will still have an Ubservable universe no matter what you do , because the speed of light is the speed of information. If I have to speculate is that because of the expansion of the observable Universe , it will come a time when All Observable Universes will become Black holes for real , meaning its surface area of the Event Horizon become larger than its Planck information.... this is EQUAL to the HEAT DEATH . My Guess is that a Big Bang will happen then , because there is a Singularity formed , because Infinite small, is no different of infinite big. This may be how all the Energy was putted imto our Universe in the first place, before the Big Bang!
The earth is only 4000 year old and the sun revolves around earth, god created us all in his own image, jet fuel doesn't melt steel beams, Donald Trump is a good president and earth is flat. (I'm impersonating everything that is wrong with with the world)
"Yes" if I pretend to understand the question. A lazy cheat I used was to substitute "entropy" for "information". Also helps me come to grips with the perceived accelerated expansion of the universe for the first and only time. YAY! and Thanks.
I am equally happy to see that there is room for a channel that does not dumb everything down to entertainment level as I am sad that this channel left me behind a while ago. There was a time in which I could stretch myself and feel my understanding grows by watching the videos. By now, it's sadly just mouth noises, interesting mouth noises, but mouth noises. Again, I'm happy this exists for the people who can follow, but maybe it would be possible to mix it up a bit?
They probably pick the "winners" randomly, check if their answer is correct and if not they roll the dice again until they have desired number of winners with correct answers.
Also the Idea of advanced Aliens or our "future selves" creating this sim is severely logically flawed, however statistically likely(as per Bostrom et al.). 1st of all, its just a desperate cling to "material/physical" ,"they're" suppose to be in the same universe they are simulating ? Why assume the "base reality" must be "in" or identical to this one ? Its just pure nonsense ! & Mostly because. This is NOT 100% consistent with how we know ALL VR's actually function. That is, the "Player" of the "game" & the computer rendering it, MUST be in the SAME reality frame as each other. Your Elf(avatar) will NEVER find the server thats generating its world in his reality. In "Rebooting the cosmos" Seth Lloyd(who I dig) conveniently & ignorantly bypasses this FACT presented by Fredkin(he has to, for the time being anyway, because his career depends on NOT being at such odds with Materialism/the status quo). So the "frame" where the computer & the player actually "are"(although space is just a 3D coordinate system/calculation) MUST be outside/elsewhere/"non-physical" from the perspective of that elf in the sim. The ONLY Flavor VR Model(s) that hit ALL of these data points is an Idealistic one such as Tom Campbell's MBT. Where Consciousness itself(BIG C) is the "computer"(metaphor). The superset. The something rather than nothing which exists(for all intent & purposes). Its just a "Natural" digital information system/field/thingy. & its nodes/copies/partitions/instantiations AKA us(little c) are the nearly completely immersed players. "It" redeners VR's to these divisions(us) as a primary evolution strategy to lower its information entropy. Not for ancestor fun ! lol. I'm NOT saying to believe it. BUT this is precisely what BEST models what we now know & assume by FAR.
pretty much but I like to just say the rendering interp as its sensible as opposed to just careful ......but you'll never even see it listed as an option anywhere......yet imaginary infinite universes & theories known to be incompatible with GR & QFT are.
Everything not inside a black hole (and maybe even inside) is being looked at by someone or *something* at every moment. Each electron "observes" its environments for electromagnetic charge for example, and does so continuously (it's about the only thing it does other than being somewhere in space and somewhen in time). Our vision is just an extension of that electron perpetual observation for EM charge (i.e. photons)
The question is based on the radius of the observable universe, but isn't it possible the the universe is much larger than our horizon? In the case that the universe is infinite then wouldn't there be an infinite radius and as such no surface area limit to information? Or do these equations help prove there is a finite universe? Chicken or egg?
Pretty sure an experiment was conducted that proved the universe is near infinite. They observed a triangle of stars and found that the angles added up. Imagine drawing a triangle on a balloon's surface, the more air you pump in the "flatter" the triangle gets. They observed the flatness of a triangle on the universe. Not 100% sure though, read about it years ago.
The limit of entropy inside a volume being proportional to the surface area is independent of what that volume is. It can be an atom, a star, a black hole, the entire observable universe, or your left shoe.
Why can't a black hole be described simply by its mass and spin? Aren't they fully symmetrical? That's why they are called a singularity, that they exist at only one point?
I've seen every episode since this channel started. We've come a long way. Well, figuratively. We have Literally gone an insignificant distance in space time since this thing started.
Don't wanna be that one smartass, but i find it very important to emphasize that you're talking about the *observable* universe, not the *entire* universe. Otherwise you risk creating major misconceptions about fundamental properties of the universe for some people.
@Eric Wesson: how would it be irrelevant? That's like someone saying in 1491 "what is outside the known world is irrelevant" or like someone saying 100 years ago "what is outside the Milky Way is irrelevant". Sure: it's possible that we never get to directly investigate what is beyond the observable horizon (you never know though) but it still has influence on us and it is part of that EVERYTHING we are trying to understand as scientists and philosophers (same thing originally). And by "it has influence on us" I mean stuff like the mysterious great attractor, which is beyond the observable universe's horizon but whose gravitational trail still tugs on us.
Hello there, first post on this channel. I think one of the important points Matt explained (at around 9:10 minutes into the video) was that for the black hole, and thus the event horizon, to actually form, the number of particles falling through the (soon to be!) event horizon has to reach the Bekenstein bound, or the number of Planck areas on the horizon. After watching the video a few times I started to realize (not absolutely certain yet!) that elementary particles really are much bigger (or somehow occupy a much bigger space!) than one Planck volume. So the correlation between elementary particles inside the black hole, and Planck areas on the event horizon actually makes sense! It's Interesting that the surface area of the event horizon grows with the black hole's mass. I wonder if that means that densities inside black holes have to reach a certain limit, maybe every single Planck volume inside the black hole cannot be occupied at the same time?
Because the questions are regarding the information in any given ONE universe, not all of them. There are an infinite number of universes that each can store a finite amount of information.
But if you could make a quantum tunneling computer that is able to take advantage of those parallel universes... then you aren't limited in computational power by the number of particles in any one universe, getting around the whole "you can only make a computer as powerful as the number of particles in your own universe" problem. Now, it's a huge ask to tunnel to parallel universes, but it's not strictly speaking an absolute theoretical impossibility, just a practical impossibility as far as we *currently* know ;) ("Currently" being a big key word there. Things can change in unpredicted and/or unexpected ways, and they often do.)
The conservation of matter/energy/information is an observable law of the physical nature of the universe. Parallel universes are theories at best. The reason there’s a limit to information is because the matter in the universe was all created in the Big Bang which of course was the start of the universe. No more matter will be created unless there’s another Big Bang I would think. At least that’s how I understand it.
Okay, I propose that he was right in assuming he's under estimating the amount of information from each Plank unit in approaching this with classic bits. The reason the final number seems to small is your starting point is wrong. Replace bits with qubits per Plank unit. A qubit is capable of storing more than one state at a time while a bit is a classical binary expression of a single variable with only two options, on or off. Qubits are much better suited to information storage in a quantum field, though what the "limit" would be is likely defined by one of the physics constants. As just a short sighted example, if the qubit storing data for each plank length had a queue depth of 32 bits in parallel, your final calculation makes a monster jump up, making the universe far too large to store in a device smaller than it without using a deeper qubit depth than reality itself on the storage media. The limit on whether the universe's entire information catalogue could be stored on a device smaller than the universe would then hinge on superior quantum storage density than reality itself offers currently. The requirement then is to create qubits with a depth greater than whatever depth of qubit the universe itself offers naturally in order to make such media. Such a "hyper-dense" qubit may not even be possible.
Heh, I just came back from the latest video on simulating the universe, which reminded me of the "dust theory" from Greg Egan's Permutation City. The line about switching off the simulation is fun because the dust theory says that's irrelevant if you switch off the simulation, it'll keep simulating itself if there are conscious beings in the simulation. Because they'll assemble themselves by picking the numbers required from any number anywhere. One of my favourite stories.
so we assume there is no form of compression we could perform on it? It is 100% patternless, has no repetition whatsoever? im gonna have to watch it again, i must be missing something
Yeah this was bugging me during the video, it didn't consider compression at all. So much of space has nothing in it and you only resolve the actual quantum information when you observe it. It should be super compressible.
'Information quantity' here and usually in information theory is post compression. It IS super compressible - if it wasn't at all we'd have 10**180 or w.e.
Frosty: there is a very clear fractal pattern but most physicists seem uncomfortable with chaos theory for some reason. This is almost certainly a horrible conceptual error that impedes scientific advance. On the other hand, you still would need to describe every 4D unit of spacetime in terms of field (at least 24 fields) and other attributes such as spin, etc. Not just space (that's a snapshot!) but spacetime!
This is what we;re looking for, a method that can compress 3D information down at a rate proportional to a 2D area. It's easy to say this but all known compression algorithms cannot do except with very special data. For example I can compress photos down using the PNG format and the size of any random picture once compressed tends to be proportional to its area in pixels. But there's no way to compress an image that we know of that makes the resulting size proportional to its width or height alone.An image twice the size (4x area) tends to be 4x larger even when compressed unless it's very derivative. (Such as a simple image resizing.) So either our universe's information is arranged in such a way that 'regular' compression is more efficient at larger scales or it relies on some other means we ahven't discovered yet.
Minecraft would be interesting to compare to. Minecraft worlds are gigantic, to where if you stored it in a raw data, it would be gigantic. Minecraft worlds have this idea of a seed. This seed determines the base shape of the world via algorithms. The amount of information with code is tiny compared to raw data. 64-bits of data determines an entire world. Another game, Pitfall on the Atari 2600, uses a similar approach. Pitfall's world is made based on a seed. Pitfall has to exist in 4 kilobytes of ROM space, and a world seed makes it simple to generate a world. The programmer chose a seed that he deemed very fun (there's a GDC presentation on Pitfall)
Also he mentioned that the black hole would be the size of the Universe. Therefore isn't our Universe inside a black hole (reversing expansion leads to a singularity, ie Big Bang Theory) and all other black holes are Universes too? ie, it's turtles the whole way down. THEN, quantum fluctuations on our Universe's Black holes event horizon is the 2D surface by which our 3+1 dimension universe is holographically projected?
"but what are a few orders of magnitude between friends?"
i love this show.
Favorite line in the video lollll why are Aussies the best content creators on the planet?? Between this and the channel I Did a Thing, I’ve learned more about nature and life and humor than anywhere else. And Tame Impala? We really should celebrate Australia in the U.S. more, heck aren’t our countries almost the same size?
@@benr3799 No.
I refuse to see anything "behind the scenes" on this channel so that I have no reason to believe Matt isn't magically floating through space.
maybe because he is a BoltzmannMatt !!DUN DUN DUUUUUUUUUU
What if a Boltzmann youtube comment formed?
"magically floating through space" - not just space but space time.
we're all magically floating through space
sinyst42 how did your comment not get more likes and comment replies
This channel re kindled my love of physics and learning almost a year ago. I'm now back in education studying physics and loving it. Thanks PBS spacetime and an especially huge thanks to matt! keep up the awesome work!
EldafoMadrengo397 wow that’s great.
It’s good to hear from someone enjoying physics as much as I am.
That is awesome.
"It would be the end...of spacetime."
I exited full-screen mode because my Pavlovian mind automatically assumed the episode had ended.
I've no background in physics, so what do you mean by Pavlovian?
@@impalabeeper It’s a reference to Ivan Pavlov, the Russian psychologist who taught dogs to salivate at the sound of a bell. He did this by giving the dogs a treat every time he rang a bell, causing them to associate the sound of the bell with receiving food.
After hearing so many episodes of this series end with “...of Spacetime” (or some variant), I heard the host say the phrase in the middle of the episode and assumed the episode had ended, just like a dog salivating at the sound of a bell. Does that make sense? :)
@@JoshSaysStuff Lol, I get it now!
"What's a few orders of magnitude between friends" 😂😂😂
Greetings from Benjamin Cohen
@@mtsbalcke im not getting out of bed for this.
Due to a universal stack overflow, the flavor of many meats has been overwritten and defaulted to plain "chicken flavor".
Gravijta You damn devs with your bad coding skills. Why can't you be more like mathematicians? - They never disappoint us with meaningless errors.
Maybe you're confusing all the meats flavors with the original dinosaur flavor they came from...
ᏰĪᏝᏝ ՇÎρɧᏋƦ
Except when they forget to carry "The One". ;)
I think I just broke a personal record for my most high pitched laugh after reading your joke. That was weird
It sounds like a line from Hitchiker's Guide to the Galaxy but I'm not sure. That is funny, but let me take you seriously for a minute. Would you need a stack? Wouldn't the state of each particle or voxel be a simple iterative process like the game of life? Seems like one while loop would do the job. There might be subroutines, but you'd need to have some kind of recursive process for that to happen.... maybe Feynman diagrams? Like, figuring out all the possible virtual particle interactions. Hmmm, hehe.
What if quantum mechanics is just an artifact of compression to make it easier to compute macroscopic physics without needing as many resources as if you were actually going to try simulating each particle down to each planck-voxel in phase-space.
If we were to build our own universe simulation, how much would implementing quantum mechanical phenomena help in decreasing the required computational load?
Indulging in the Simulation hypothesis for a moment: Humanity's exploration of physics appears dangerously analogous to reverse engineering unknown computer hardware. I think we're becoming aware of things that weren't expected to be noticable. Who knows, we could eventually come across a physics glitch that we could exploit for FTL communication or something.
great question
I shit you not, trying to develop a distributed physics engine for a game, it is VERY UNCANNY how many phenomena of actual physics are conducive to unrestricted parallelization. There are global speed limits so that in a finite time the cluster can gather all causal events in your light cone before deciding what happens to you next... there is the heisenberg uncertainty principle so you don’t have to waste cpu cycles resolving exact details of every aspect of particles for an observer... Quantum tunneling (or its cause, the wave function) is a lazy but efficient work around to avoid resolving newtonian collision on every scale of spacetime.... In higher energy (higher gravity) regions of space, time runs slower, because it is more computationally intensive than low energy areas of space... Relativity of spacetime means physics is stable to compute inside massive inertial bodies, even if outwardly the body is at a high velocity compared to a different body (no global notion of velocity). I bet there are even more I havent discovered yet
Edit:
Quantization of matter and energy, in contrast with infinitely and infinitesimally continuous and differential space and particles. If the universe was a living and moving and breathing fractal with no quantization (no 'minimum' metric for various physical properties, the so called plank metrics), then this would lean slightly in opposition to the universe being a simulation, but since everything is quantized, this aspect actually leans slightly in favor of the the universe being a simulation.
Sorry, I don't understand how the encryption and fuzzing relate? It sounds like you're describing compression, but even then I'm not quite sure how that related to the seemingly random nature of quantum mechanics.
I understand that really good compression will resemble randomness (as would encryption), but I don't understand how that would drive quantum mechanics.
@Andrew Brown There's an ~~xkcd~~ smbc for everything: www.smbc-comics.com/?id=2535
@James that is so spot on
Man, all these standalone videos are leading up to the Holographic Universe Avengers movie.
I hope Matt is the One Above All
Mike Volume joss Weadon get in here now!
No, they agree going to kill off your favourite dimension using Infinity calculations.
It's called CUM (converted universal multiplane)
Particles Assemble!
I admire you. (and your viewers who interact) Intelligent, well spoken, etc. This subject is beyond my intellect, but I do understand the basics of what you are presenting. I've always been fascinated by this, and enjoy watching the advancement of science and its realisation of space time. We've come a long way, and hopefully a long way to go. Thanks sooo much for your show and the effort you put in to it.
I think all of these numbers can be equally explained as:
Big AF
The universe is under no obligation to tell us how much information it has. Respect its privacy.
Rita Eric Interesting perspective. One problem, though: aren't we humans the universe's eyes and brains with respect to RUclips observations?
I'm sure there are much higher novelties in the social media genre out there in some distant spot in the universe, witnessed by vastly superior intelligence than our own.
But where is this info stored? And will it get erased? If so, what then?
[Laughs in NSA]
Did he just assume the universes information? Cant beleive the white privileged male went there. That’s it I’m starting a movement I’m with everything.
If jesus appeared out of nowhere and said he has the solutions to our problems but wont fork em over wyd
What like Mexican Jesus or crazy white Jesus?
How much information is in the universe? "All of it"
You are technically correct, which is the best kind of correct.
I literally just clicked on this video to comment that. Take the dub.....but also dang you....dang you to heck
LOL well all of it for THAT universe. Unless some escaped... oh never mind lol
The same thought crossed my mind, well said Sir.
Who knows? Maybe the information defining our universe exist outside of it. Example : If you simulate a world using your PC, the information about the world is contained on a Hard Drive, RAM etc. If there was intelligent beings in that simulation, they could not directly observe there is a PC at all. They would believe the information is contained within the Universe too.
Your Neverending Story reference has earned my undying subscribership.
ARTAAAXXXXXX!!!
I cannot even begin to imagine the types of compression algorithms that our computer scientist buddies would come up with to compress the universe
It was already compressed. It's now unpacking because the universe is growing 😋
On a lighter note , the bang was inevitable , all that potential not be expressed, untenable.
this is one of the only channels that manages to make my head hurt.
Try some tele envangelica channels then
@@jacobjorgenson9285 those make me angrier than anything. they take advantage of the weak and desperate.
The whole universe is 40gb
Haven’t you played NO MANS SKY?
This is actually an important question, does the universe use procedural generated content?
Only 14 trillion mostly small planets and no real atmosphere physics, no real orbital mechanics, no space time.
i can see the point and it is a very good way of thinking about the programing to keep it fast and lower mass. but i think that would actually work but if are we trying to compute every Planck time from start to end or just in the moment because if its just right now we can over lay existing information into the programing to give reference that could take less computational power and if they are at that point very likely an AI running in it could create all the deviations itself at the start and just keep it stable running diagnostics or shut it off to more effectively use the area.
If so we got a shitty seed.
*SLOW CLAP INTENSIFIES*
Thumbs up for middle-out hahaha. Always grateful for the nerd jokes.
We're gonna need to compute the required DTF ratios.
Not hotdog.
@@billmalcolm4291 but did you assume a correct Mean Jerk Time (MJT)?
Matt's videos are always just beyond my level of understanding, but close enough to keep me hooked.
It must take days to sync it to the backup server.
... backup?
Is the backup server located in an other universe? I mean, it's not smart to have a backup of your hard drive on your hard drive... That would kind-of defeat the purpose of backing it up...
No worries. It's stored in the cloud.
terry boyer must be a big cloud
@@Zzz-ghostyyy Oh all these poor nebulae full of unnecessary data...
I look forward to these episodes more than pretty much anything. It helps keep me going some days. Thank you ever so much, as sincerely as I can convey in a YT comment. This is extremely needed; Darkest timeline and all that...
Less than the amount of subscribers that you guys deserve
The Exoplanets Channel I was just thinking this as I clicked on the video. These guys rock.
Agreed
Learnt a lot from this fella. I like him.
"Middle out." lol @ the D2F ratio on this guy.
But the subscribers are in the the universe.
How much of that data as a percentage is porn? 🤔
Well, if the internet is any indication, my guess is 99.99987+.
You ever seen a star with clothes on?
stars are sexy
Surprisingly high if we consider only biological systems and we have an open mind for what porn is (for example is animal nudity "porn"?) But surprisingly low considering most systems are non-biological. Now let's wait for "black hole porn" (no, not that kind of "black hole", I mean the one physicists deal with professionally), if that kind of nerdy porn ever happens, then it'll be 100% and the word "porn" would lose all meaning.
Rounding as a cosmologist or an astrophysicist?
Those challenge questions are tough. I'll have to give them some Deep Thought. Though I'm leaning towards an answer of 42.
Thank you, thank you for keeping the background music/sound design down to an almost imperceptible level, so that we can hear Matt's amazing content! Other RUclipsrs, please take note....
Please stop that terrible noise in the back ground. The stuff you are talking about needs all my attention, there is no room for disturbing rubbish
This idea of a practical computing device based on a black hole is a fascinating science-fiction concept. A laptop with a kugelblitz inside would however be rather heavy.
Thirteen... right? It's gotta be thirteen metric informations.
It's 42. How can anyone not know that after the prophet Douglas Adams told us.
@@PhilipLeitch No, 24. That's the largest number, fuhgeddaboudit.
Jeff Fecke damn, dude. I only know how to count to five
At least you can count to 5. I know of a game dev team that struggles to count past 2.
@@Selvyre its because valve does everything in ternary. they only know the numbers 0 1 and 2
Could a boltzmann brain turn into a black hole if it learned too much?
chtoffy great question! Well, trying to memorize Graham's number should turn one's brain into a black hole! :)
I think it would just be unable to store more info beyond a certain point (unless it like, got more material in order to store more info, in which case it might collapse)
This also implies that, unless it keeps getting bigger and bigger without bound(though possibly incredibly slowly), that its states will eventually repeat, so insofar as one's life consists of one's experiences, then assuming that all one's experiences in this world correspond to physical states, the sum total of the thing's experiences, and therefore its life, must be finite, and that therefore it must be mortal.
Unless the Bekenstein bound somehow turns out to be incorrect, or there is some way to grow in size without bound, then if there is any hope for immortality, it must come from outside this world.
"And the last enemy to be destroyed is death." 1 Corinthians 15:26
If natural selection is able to apply exponentially increasing selection pressures on it (natural selection of ideas), and there is enough lower energy states to feed it's growing complexity (exploiting faster interactions at lower cost). You could get a entropy hole. It wouldn't be able to stop either because if one part of the brain gets "Lazy" the other parts will cannibalize it, or leave it behind as it shrinks to lower energy states. If you can divide energy to infinity, then it could live forever, relative to it's perspective, but relative to our perspective... we would see it disappear, and maybe even destabilizing space, by causing a pressure differential in the vacuum.
He meant a Boltzmann _brane,_ not _brain._
Yes, yes it could.
9:16 I thought it was the end of the ep... my heart skipped a beat..
PBS space-time is not the channel we deserve, but we the one we really need. If anyone is reading this archived comment after 100 years. Ssup? How's your house boat? There was something solid like the floors you stand on in our times...it was called land.
At 9:15 when he says Space Time I started looking for a new video to watch thinking it was the end but it definitely wasn’t.
"what's a few orders of magnitude between friends?"
awesome :D
This was very informative
@@12xenn45 shut up dude
How observant, and yes it was😂
budum tis
ISWYDT
As the universe expands, its volume increases faster than its surface area. Since the amount of information is limited by the surface area, does this mean that the amount of information that can be contained in a given volume of space (i.e. a cubic lightyear for example) decreases over the lifetime of the universe, or is that just an average?
Also, is there a relationship between entropy and dark energy? Since entropy increases over time, which requires more information to describe the macro-state of the universe and more information in turn means the universe should need a larger surface area to store all that information, which in turn requires an increase in its volume, it seems there might be some interaction. To ask in a different way, does the acceleration of the expansion of the universe follow the square cube law?
This is the most intriguing question so far. I _really_ hope Dr. Dowd answers it!
And I'm not sure if we ever got an adequate explanation as to why expansion of space only seems to occur in voids between galaxies and not evenly across all space. Am I mistaken that the expanse between here and the moon is comprised of the same "space" that is expanding? I get that baryonic matter is gravitationaly bound but surely we could observe Lambda locally and not just via the redshift of distant galaxies. No?
To add to this question, if information/entropy really is "imprinted" on the surface area of the universe, then it follows that since the volume of the universe increases faster than its surface area, information density must also increase along with the expansion of the universe. Does there come a point at which the information density of the universe exceeds the Bekenstein limit and the universe becomes a black hole -- or is this prevented by conservation of energy? To put it another way, does expansion create new information, or is the information content of the universe constant (ignoring transient loss of energy to black holes and the like)?
Mercurius314 "more information in turn means the universe should need a larger surface area to store all that information" - not so. As is explained in this video, the informational capacity of the existing volume is far from being exhausted. So there is plenty of room for entropy growth in the existing volume (and associated surface area). But I wonder what would happen if most galaxies were consumed by their central black holes. Could the cumulative entropy of the resulting black holes exceed the maximum permissible entropy of the Universe?
My understanding is that it is all space, earth-moon or even the atoms in your fingernails. But since it's fractional small distances have a small, perhaps immeasurably small, increase in absolute terms.
"maybe Artax will come back too"
TOO SOON MAN, STILL TOO SOON
Your videos are so dense (in a good way)!
I'm going to need a larger hard drive.
How 'bout a black hole hard drive?
“Maybe middle out.”
Richard be like, I invented it!!
Question: If time and space started with the big bang. How would other universes measure our time? The same way we measure the time of a book, as a fixed beginning middle and end that we exist outside of?
Where would the black hole singularity of our black hole be, then?
That depends on what theory you use for your multiverse. Different ones have different answers.
This video gets extra love for bringing up the Nothing and Falkor to illustrate the complexity of the universe.
The brief sigh into "rather a large amount of particles" was golden
Idk why, but I like the way this guy talks.
Is there a link between the expansion of the universe, the second law of thermodynamics, and the holographic principle?
So, the universe is really just deep thought calculating the answer to life, universe, and everything?
Yes, but it's going to take some time.
7.5 million years, more or less. However, since we are part of that simulation, we can't assume that our time runs in the same frame of reference as Deep Thought. 7.5 million years could end up being several eternities to us.
yup, or as I say Miratus Machina, The Wondering Machine
The question! We already know the answer is 42.
Hmm... maybe the question is how many bits of info are actually needed to describe each 4D plankspacetime "voxel"? Do I get candy for guessing it?
Amazing is the fact that from Area information law you can derive the Einstein general relativity equations. That should be the next episode ...
Anyone attempting the challenge question should also read the hitchhiker's guide to the galaxy before submitting. It was poking fun with some of these concepts back in 1985.
Also I recommend learning about coding theory. As an EE grad student I took a class called "Information Theory" and it was life changing. Without having to do the math heavy statistics I'd say if you can find someplace online that teaches how to hand encode and decode huffman and lempel-ziv (and you can actually do them) you're halfway there. The other half is shannon's source coding theorem, the law of large numbers, and a few other stats laws I forget now :x
Of all of those things the most important concept is shannon's source coding theorem which is intuitive and can be taught easily because it's so easy to demonstrate.
Take an uncompressed bitmap image of noise, just randomly placed intensity values, and put it in a zip archive.
Take another uncompressed bitmap of the same size but only one color, and put it in a zip archive.
No information was lost in compression because you can extract the exact same image that you put in. The image of noise will be the same size (maybe a few bits larger) than the uncompressed version but the image of just one color will be tiny.
Lastly I have a fond memory of a homework problem from that class: There are two weathermen in a city that only report if it will be sunny or cloudy on a given day. One weatherman is right half of the time while the other is right a quarter of the time. Which one gives more information about the weather? Use the definition of entropy to prove it.
I am curious good sir, is there any form of compression that can reliably reduce a dataset of x^3 bytes to an output of X^2 or a multiple thereof? You sound like the person to ask.
Procedurally generated universe, our seed is 42 of course
Use universe density of mass or something like elementary particle to calculation the universe "Effective density" gave by the equation:
ρ=3H^2/8πG
Because in the video , you say "if niverse fully filled the at the moment the universe reached its informational limit you would immediately become a black hole ", so use the same logic , if we use cosmic radius multiply "Effective density" , then we get the radius of black hole computer.
R=universe radius x effective density
=(138ly)(3H^2/8πG)
=(138ly)(0.85×10−26)
=(117.3 x 10^-26)
This is almost Approaching to 0
t=Q/V(black hole computer sarface area)
Q:Calculated amount=(4/3)πρ(c/H)^3
t:time
But i won't calculate the t , so suppose the t=138^9 year
so the v=(4/3)πρ(c/H)^3/138^9 year
but that still does not exist, too unreasonable
Wow, this so cool
Assuming 1 bit per elementary particle is nonsense: to describe any single, say, electron, you'd need a lot of information:
1. location (probability of location), which alone takes a huge amount of bits if described at universal scale in binary form)
2. type of field: the fact that it is an electron and not a Z boson or a charm quark must be informed, this again takes a substantial amount of bits because there are 24 QFT fields (at least), in some cases with more than just one bit of possible info: electric charge needs two bits because it can be positive (10), negative (01) or nonexistent/neutral/empty (00), color charge needs three bits (we can compress the anticolor of gluons but not the anticolor of antiquarks), etc.
3. particulars of the particle such as spin (another bit), energy state (probably several bits), etc.
That basically makes the amount of info at every particle needing five bits at least (if what I read about 61 "fields" with max. info is correct), PLUS you also need to describe location in space and time (the matrix is also information!), which at the Plank scale seems to require lots of bits (your usage of base 10 numbers does not help here, could you use hexadecimal instead?, in any case LOTS).
The only question remaining open for me is that, because particles are much larger than the plank unit of space (uncertainly so but statistically they are), IF there is enough empty space (or quasi-empty space) to compensate the scalation of figures.
A problem I can't underline enough is that you can't just code the universe in *space* but you also need to do so *in time*, else you'd only get a snapshot with no causality attached, and that seems even more daunting and more bit-intense (a photon can be in many plankspaces but "ticks" at planktime units AFAIK).
Watch the video again, and pay attention to the bit about phase space.
How does it matter, Michael? I can understand that phase space formulation would allow to compress some of the info but only for as long as no interaction happens (example: a photon traveling in ideal vacuum). But interactions do happen all the time, and they are chaotic in nature (more so considering quantum uncertainty).
The more I look at this, the more confused I get. It made perfect sense at first, but now ... . At any rate, it wasn't on the curriculum when I was in school, so I'm having to play catch-up fast. Perhaps, and this is just a guess, it has to do with the difference between classical and quantum information. Or perhaps not.
Can't say. I also assume I'm missing something important, that's why I posted my objections: not to win any argument but to see if someone could win it against me and teach me something.
Luis Aldamiz
Ok, assume that you don't need 1 bit, but 1000 bits to describe an
elementary particle. What's the effect ? Instead of 10⁹⁰ you now have
10⁹³.bits. Do you feel better ? That's exactly what he meant about
rounding and ignoring small disturbances in the presence of larger
numbers. 10⁹³ is of course 1000 times bigger than 10⁹⁰, but relative to
10¹²⁴ its still pretty irrelevant and can therefore be neglected in
first approximation.
Wow. That was such a beautiful episode. My mind was blown to see how far cosmology can be taken. Creatively solving creative problems.
I love Space Time! Thank you PBS and thank you Matt!
I've been to arrogant to consider watching videos about space and time. I thought I already knew everything there was to know, and I think I was afraid of learning more. All the titles just looked like clickbait, and I didn't think I'd gain anything real from them. Or maybe I was afraid I would. My roommate convinced me to watch though, and now I think I'll continue to watch every video you guys make. I might even go back and take notes.
So... has the universe ever been in a state of "too much information in too little space"? Particularly during the big bang? Is this what we mean when we say that the universe was too hot for some particles to form? ie was the universe too dense in information to allow all the required quantum states for classical matter until it expanded?
Good question.
It's a silly question really, since here "information" means something without any material substance, even though they don't say it straight. If a thing doesn't have any dimensions, we can't talk about it's density. This documentary is just pseudoscience. There's no scientific basis to argue that the material universe is fundamentally made of something non-material. Information, as we know it, is always in some material form or another, whether it's computer data or genetic information. In essence, the model proposed here is a modern day version of Plato's world of ideas = idealism.
I'd advise you to look up "Dunning-Krueger effect" before you further embarrass yourself.
Henri Rauhala, Information is an abstract concept, similar to Natural numbers. Do natural numbers exist physically?
bormisha, information can be both abstract and concrete. There's concrete information like computer data, existing in electronic circuits. Abstractions are a product of human mind. In quantum physics for example, abtractions help scientists to make sense of highly complex processes. However, abstractions don't exist as such, like you said, let alone form the basis of reality. Trying to put these hypothetical cosmic "bits" into a measurable form is like chasing ghosts, pure nonsense. Professor O'Dowd here attempts to capture the ghosts into two-dimensional boxes. Furthermore, he doesn't even try to explain what space itself would be, considering his assumption that all reality is "informational". Any credible scientist shouldn't waste time building metaphysical models like these. We already have plenty of mysteries in the cosmos waiting to be solved.
I'm a bit confused by thinking that the estimate of storing each particle as a data point is anywhere close to accurate: You're assuming that 1 particle = 1 bit of information ... but you can't even begin to describe even a single particle with just 1 bit of information. Even something as basic as 'what sort of particle is it?' is going to take several bits. (6 bits for particle type alone, assuming each of the 38 fundamental particles is assigned a binary number to represent it.) And that's not to mention things like location, energy level, momentum, direction of movement... I'm sure that a well-crafted storage scheme could minimize the size of that fairly well, but it's still going to be far more than 1 bit per particle. It could take hundreds or thousands of bits to describe a single particle, depending on how fine-grained your measurements of things like position and velocity are going to be. Is there even any limit whatsoever to how small the differences in momentum between two particles can be? Each particle might require enormous amounts of data to describe that accurately.)
Along the same lines, there's a similar problem with assuming 1 bit per Planck volume -- Suppose the bit for a given volume is '1' ... what does that mean? What would it mean if that value is '0'? Does a '1' mean that there's an up quark there? Or is it an electron? Maybe a gluon? Or a photon? If it's a photon, what direction is it traveling, and what's its wavelength? There can be far more information in that Planck volume than could be described with a single bit of information.
Not trying to nit-pick, but the 1-bit assumption seems to be an enormous assumption to just be throwing around with no explanation.
O Ocalhoun
Ok, assume that you don't need 1 bit, but 1000 bits to describe an elementary particle. What's the effect ? Instead of 10⁹⁰ you now have 10⁹³.bits. Do you feel better ? That's exactly what he meant about rounding and ignoring small disturbances in the presence of larger numbers. 10⁹³ is of course 1000 times bigger than 10⁹⁰, but relative to 10¹²⁴ its still pretty irrelevant and can therefore be neglected in first approximation.
I think you missed the point. He’s just simplifying to get the message right. If it takes 1 bit or 1MB it’s irrelevant for the topic and to the magnitudes at discussion (just add a few more units to the exponent)
String theory assumes particles are vibrating on the same string, since all those variables you mentioned then start to break apart, a single bit can describe a single particle as the bit is also a string
According to group theory, you can describe an elementary particle with basically two numbers, mass and spin - but you're right, this whole video is more of an analogy than a real hard argument. Truth is, the number of bits/unit volume is just the computation of the entropy available - and since BHs (supposedly) contain most of the entropy of the Cosmos, that's what this all boils down to. If there were no BHs, we'd go to the next best thing, the CMB, and so on. Also, bear in mind the Bekenstein bound is not so much an statement on the limit of information admissible in the Cosmos as a _consequence_ of our current understanding of gravitational collapse
I'm just here for the pony avatar.
7:11 For me that's the key to understanding the "Holographic Principle":
- no need to know the positions of particles inside a BH, so the Info content might fit on its Surface,
- especially as the BH's Surface increases by 1 Planck Area each time it absorbs a Photon Mass-Energy [cf. Susskind, The Black Hole War]
This episode was the best in a while.
10^38 and use a DNA folding process to save info. Solved. Now let’s work on commercial flights into space!
It would appear that we are NOT inside a black hole since Matt pointed out previously that inside a black hole space and time swap meaning and all you have inside the black hole is an inevitable future at the singularity (unless the singularity is the "Great Attractor"). In that case, what would happen if the super massive black hole at the center of our galaxy hits the singularity of our entire universe (assuming we are inside a black hole and not just a holographic non-black-hole universe?
Awesome idea. I don’t think we would hit the singularity though if it were the great attractor. We would just orbit it like everything else in the universe does.
I saw a documentary a while back where many well known physicists used to believe the universe was shaped like a donut or a figure eight and that all the matter in it was orbiting something at the center then looping back around. Awesome stuff.
Middle out! It’s so obvious! -god
Well, middle-out compression was proposed at 5:30.
I think there's some compelling arguments for it.
Radioactive decay isn't entirely random. It can be affected by proximity to the sun. This was noted by a team of physicists from Purdue and Stanford. They were trying to use radioactive decay to generate random numbers, but noticed what appeared to be "seasonal" changes in decay rates. These changes were significant and although much more work needs to be done on the subject, it seems that as the earth paths closer to the sun it affects the decay of particles. I'm thinking we just discovered a way to detect gravitons, maybe?
To simulate the Universe, you don't have to simulate it all at once. Using procedural generation, the particles in some region of space would only be simulated when they were actually looked at. The only risk would be that many particles simulated together might behave differently than you'd expect from studying single particles. So for example the simulation of multiple particles through two small slits could calculate a wave pattern, but the detailed simulation of single particles would give a different pattern, due to the level of detail of the simulation.
Does the Bakenstein bound also put a limit to the density of the universe or to the density of a given region? Like, as the radius increses, the volume increses by r^3 and the maximum number of particles increases by r^2, the limit density should be proportional to r^(2/3)?
Pedro Cardoso I wanna know this too!
Bekenstein* (sorry to point out the correction) but I would like to know the answer to this too...
Yes, the maximum density is that of a black hole. What this means is that larger black holes are less dense than smaller ones. The one at the center of our galaxy for example is only about as dense as lead and far less dense than a small neutron star.
Spacetime episodes contain so much information, there is little left for everyone else in the universe. Guys, stop hogging everything to Yourself! Share a bit... wait...
So all the information in our local area of the multiverse is contained on the surface boundary of the universe, but doesn’t the surface area grow over time, and doesn’t the surface area of every region of the universe outside our particle horizon also grow faster than the speed of light?
All of the observable universe is an Imaginary black hole for the Hole Universe if i may say that....Its Event horizon its defined by the speed of light. It doesnt matter where you are in the Universe ....you will still have an Ubservable universe no matter what you do , because the speed of light is the speed of information. If I have to speculate is that because of the expansion of the observable Universe , it will come a time when All Observable Universes will become Black holes for real , meaning its surface area of the Event Horizon become larger than its Planck information.... this is EQUAL to the HEAT DEATH . My Guess is that a Big Bang will happen then , because there is a Singularity formed , because Infinite small, is no different of infinite big.
This may be how all the Energy was putted imto our Universe in the first place, before the Big Bang!
The earth is only 4000 year old and the sun revolves around earth, god created us all in his own image, jet fuel doesn't melt steel beams, Donald Trump is a good president and earth is flat. (I'm impersonating everything that is wrong with with the world)
DirtyAether why is Donald Trump not a good president?
"Yes" if I pretend to understand the question. A lazy cheat I used was to substitute "entropy" for "information". Also helps me come to grips with the perceived accelerated expansion of the universe for the first and only time. YAY! and Thanks.
@@Nathan-yk5km don't ask stupid questions
Please never stop making these videos
I am equally happy to see that there is room for a channel that does not dumb everything down to entertainment level as I am sad that this channel left me behind a while ago. There was a time in which I could stretch myself and feel my understanding grows by watching the videos. By now, it's sadly just mouth noises, interesting mouth noises, but mouth noises. Again, I'm happy this exists for the people who can follow, but maybe it would be possible to mix it up a bit?
Are you reading every single challenge answer? I am very curious if right answer can be overseen considering that you have 1.3M subs.
The vast majority never attempt the challenges.
They probably pick the "winners" randomly, check if their answer is correct and if not they roll the dice again until they have desired number of winners with correct answers.
If 1.3 mln people each submit a random answer, and keep submitting for the age of the universe, eventually one of the answers will be true!
Hope the computer does not need to contain all the thumb up's for you I have in mind, because the required capacity would be infinite ;)
You only have to "render" things/places that are actually being looked at(measured). That's Basic computer science/digital physics.
Also the Idea of advanced Aliens or our "future selves" creating this sim is severely logically flawed, however statistically likely(as per Bostrom et al.). 1st of all, its just a desperate cling to "material/physical" ,"they're" suppose to be in the same universe they are simulating ? Why assume the "base reality" must be "in" or identical to this one ? Its just pure nonsense ! & Mostly because. This is NOT 100% consistent with how we know ALL VR's actually function. That is, the "Player" of the "game" & the computer rendering it, MUST be in the SAME reality frame as each other. Your Elf(avatar) will NEVER find the server thats generating its world in his reality. In "Rebooting the cosmos" Seth Lloyd(who I dig) conveniently & ignorantly bypasses this FACT presented by Fredkin(he has to, for the time being anyway, because his career depends on NOT being at such odds with Materialism/the status quo). So the "frame" where the computer & the player actually "are"(although space is just a 3D coordinate system/calculation) MUST be outside/elsewhere/"non-physical" from the perspective of that elf in the sim. The ONLY Flavor VR Model(s) that hit ALL of these data points is an Idealistic one such as Tom Campbell's MBT. Where Consciousness itself(BIG C) is the "computer"(metaphor). The superset. The something rather than nothing which exists(for all intent & purposes). Its just a "Natural" digital information system/field/thingy. & its nodes/copies/partitions/instantiations AKA us(little c) are the nearly completely immersed players. "It" redeners VR's to these divisions(us) as a primary evolution strategy to lower its information entropy. Not for ancestor fun ! lol. I'm NOT saying to believe it. BUT this is precisely what BEST models what we now know & assume by FAR.
Right! And don't forget good ol' Z-buffer occlusion. I remember when that was still a new technique...old feels.
So basically the Copenhagen interpretation of quantum mechanics where uncertainty is thought of as the act of observation determining the result? :P
pretty much but I like to just say the rendering interp as its sensible as opposed to just careful ......but you'll never even see it listed as an option anywhere......yet imaginary infinite universes & theories known to be incompatible with GR & QFT are.
Everything not inside a black hole (and maybe even inside) is being looked at by someone or *something* at every moment. Each electron "observes" its environments for electromagnetic charge for example, and does so continuously (it's about the only thing it does other than being somewhere in space and somewhen in time). Our vision is just an extension of that electron perpetual observation for EM charge (i.e. photons)
I never get alerts anymore to new episodes. I must have blown your minds with deep questions that made you wonder about your mortality.
I love you guys, you skyrocketed my interest in physics
More importantly can the computer that is simulating our universe run Crysis at ultra settings 😛.
The question is based on the radius of the observable universe, but isn't it possible the the universe is much larger than our horizon? In the case that the universe is infinite then wouldn't there be an infinite radius and as such no surface area limit to information? Or do these equations help prove there is a finite universe? Chicken or egg?
Pretty sure an experiment was conducted that proved the universe is near infinite. They observed a triangle of stars and found that the angles added up. Imagine drawing a triangle on a balloon's surface, the more air you pump in the "flatter" the triangle gets. They observed the flatness of a triangle on the universe. Not 100% sure though, read about it years ago.
The limit of entropy inside a volume being proportional to the surface area is independent of what that volume is. It can be an atom, a star, a black hole, the entire observable universe, or your left shoe.
Why can't a black hole be described simply by its mass and spin? Aren't they fully symmetrical? That's why they are called a singularity, that they exist at only one point?
Check out this episode: ruclips.net/video/9XkHBmE-N34/видео.html
Also electrical charge.
I've seen every episode since this channel started. We've come a long way. Well, figuratively. We have Literally gone an insignificant distance in space time since this thing started.
This channel is unbelievable good!!
How do you keep your beard so awesome! What’s your techniques!
4:08 "What's a few orders of magnitude between friends?"
SCIENCE IS FRIENDS WITH NO ONE!!!
My name isn't science
Don't wanna be that one smartass, but i find it very important to emphasize that you're talking about the *observable* universe, not the *entire* universe.
Otherwise you risk creating major misconceptions about fundamental properties of the universe for some people.
Thank you: I did have that doubt myself.
Do you mean fundamental properties of the entire or just the observable universe?
@Eric Wesson it's not. Far as we know, maybe most of the matter is outside the observable universe. Who's gonna count those bits?
@@tatjanagobold2810 entire
@Eric Wesson: how would it be irrelevant? That's like someone saying in 1491 "what is outside the known world is irrelevant" or like someone saying 100 years ago "what is outside the Milky Way is irrelevant". Sure: it's possible that we never get to directly investigate what is beyond the observable horizon (you never know though) but it still has influence on us and it is part of that EVERYTHING we are trying to understand as scientists and philosophers (same thing originally). And by "it has influence on us" I mean stuff like the mysterious great attractor, which is beyond the observable universe's horizon but whose gravitational trail still tugs on us.
I really like this fella. Learnt so much from him.
Hello there, first post on this channel.
I think one of the important points Matt explained (at around 9:10 minutes into the video) was that for the black hole, and thus the event horizon, to actually form, the number of particles falling through the (soon to be!) event horizon has to reach the Bekenstein bound, or the number of Planck areas on the horizon.
After watching the video a few times I started to realize (not absolutely certain yet!) that elementary particles really are much bigger (or somehow occupy a much bigger space!) than one Planck volume. So the correlation between elementary particles inside the black hole, and Planck areas on the event horizon actually makes sense!
It's Interesting that the surface area of the event horizon grows with the black hole's mass. I wonder if that means that densities inside black holes have to reach a certain limit, maybe every single Planck volume inside the black hole cannot be occupied at the same time?
Nobody ever said that elementary particles are one Planck unit large. Of course they are bigger than a Planck volume.
Is't this a paradox to the parallel universe theory? How can their be a limit to information when their is no limit to amount of parallel universes?
Because the questions are regarding the information in any given ONE universe, not all of them. There are an infinite number of universes that each can store a finite amount of information.
But if you could make a quantum tunneling computer that is able to take advantage of those parallel universes... then you aren't limited in computational power by the number of particles in any one universe, getting around the whole "you can only make a computer as powerful as the number of particles in your own universe" problem. Now, it's a huge ask to tunnel to parallel universes, but it's not strictly speaking an absolute theoretical impossibility, just a practical impossibility as far as we *currently* know ;)
("Currently" being a big key word there. Things can change in unpredicted and/or unexpected ways, and they often do.)
@@DeathBringer769 "exactly", considering a given set of "universes" 😆
The conservation of matter/energy/information is an observable law of the physical nature of the universe. Parallel universes are theories at best. The reason there’s a limit to information is because the matter in the universe was all created in the Big Bang which of course was the start of the universe. No more matter will be created unless there’s another Big Bang I would think. At least that’s how I understand it.
@@kylemiller2414 dunno...
en.m.wikipedia.org/wiki/Black_hole_information_paradox
*Easy to answer: there 16k ROM and 2k Ram* .
This is about the holographic principle isn't it
I think.
No shit sherlock
How did you figure that one out Einstein?
Okay, I propose that he was right in assuming he's under estimating the amount of information from each Plank unit in approaching this with classic bits. The reason the final number seems to small is your starting point is wrong. Replace bits with qubits per Plank unit. A qubit is capable of storing more than one state at a time while a bit is a classical binary expression of a single variable with only two options, on or off. Qubits are much better suited to information storage in a quantum field, though what the "limit" would be is likely defined by one of the physics constants.
As just a short sighted example, if the qubit storing data for each plank length had a queue depth of 32 bits in parallel, your final calculation makes a monster jump up, making the universe far too large to store in a device smaller than it without using a deeper qubit depth than reality itself on the storage media. The limit on whether the universe's entire information catalogue could be stored on a device smaller than the universe would then hinge on superior quantum storage density than reality itself offers currently. The requirement then is to create qubits with a depth greater than whatever depth of qubit the universe itself offers naturally in order to make such media. Such a "hyper-dense" qubit may not even be possible.
Heh, I just came back from the latest video on simulating the universe, which reminded me of the "dust theory" from Greg Egan's Permutation City.
The line about switching off the simulation is fun because the dust theory says that's irrelevant if you switch off the simulation, it'll keep simulating itself if there are conscious beings in the simulation.
Because they'll assemble themselves by picking the numbers required from any number anywhere.
One of my favourite stories.
The answer is 1 terabyte
meme thats 2 petabytes, your off by alot. theres far more information that that on the internet alone
meme Did you mean: YOTTABYTE
Nope, 1 google to the power of 42 googles.
piss
Over 9000...
so we assume there is no form of compression we could perform on it? It is 100% patternless, has no repetition whatsoever?
im gonna have to watch it again, i must be missing something
Yeah this was bugging me during the video, it didn't consider compression at all. So much of space has nothing in it and you only resolve the actual quantum information when you observe it. It should be super compressible.
'Information quantity' here and usually in information theory is post compression. It IS super compressible - if it wasn't at all we'd have 10**180 or w.e.
Kanyda: "nothing" is teeming with virtual particles.
Frosty: there is a very clear fractal pattern but most physicists seem uncomfortable with chaos theory for some reason. This is almost certainly a horrible conceptual error that impedes scientific advance.
On the other hand, you still would need to describe every 4D unit of spacetime in terms of field (at least 24 fields) and other attributes such as spin, etc. Not just space (that's a snapshot!) but spacetime!
This is what we;re looking for, a method that can compress 3D information down at a rate proportional to a 2D area.
It's easy to say this but all known compression algorithms cannot do except with very special data. For example I can compress photos down using the PNG format and the size of any random picture once compressed tends to be proportional to its area in pixels. But there's no way to compress an image that we know of that makes the resulting size proportional to its width or height alone.An image twice the size (4x area) tends to be 4x larger even when compressed unless it's very derivative. (Such as a simple image resizing.)
So either our universe's information is arranged in such a way that 'regular' compression is more efficient at larger scales or it relies on some other means we ahven't discovered yet.
There is no spoon!
Adrian Gray hilarious
Minecraft would be interesting to compare to. Minecraft worlds are gigantic, to where if you stored it in a raw data, it would be gigantic. Minecraft worlds have this idea of a seed. This seed determines the base shape of the world via algorithms. The amount of information with code is tiny compared to raw data. 64-bits of data determines an entire world.
Another game, Pitfall on the Atari 2600, uses a similar approach. Pitfall's world is made based on a seed. Pitfall has to exist in 4 kilobytes of ROM space, and a world seed makes it simple to generate a world. The programmer chose a seed that he deemed very fun (there's a GDC presentation on Pitfall)
This completely blows my mind
How Much Information is in the Universe?
Answer: All of it
/end video
42
The answer is always 42
FALCORE!!!
falcom punch!
thanx for paper links, It helps a lot.
"Yuck, you round like a cosmologist" :D
Wait, if the universe gets more information, wound't it just grow and expand its surface?
Why would it turn into a black hole?
Also he mentioned that the black hole would be the size of the Universe. Therefore isn't our Universe inside a black hole (reversing expansion leads to a singularity, ie Big Bang Theory) and all other black holes are Universes too? ie, it's turtles the whole way down. THEN, quantum fluctuations on our Universe's Black holes event horizon is the 2D surface by which our 3+1 dimension universe is holographically projected?
And there we have the person obsessed with Donald Trump. Go seek professional help so you can learn that this video is about PHYSICS and NOT politics.
We're in the Matrix
that's what eastern mysticism has always said.
I watched this to feel smart i didnt understand anything
Please make a video explaining composition of Jupiter as a gas giant. Videos are amazing anyway! Kudos!
Mathew I really enjoy the way you say "ten to the power of..."