Computing a Universe Simulation

[@CevelNet]

You know you did an extremely good job at AI programming, when the characters in your simulation start wondering if they are simulated.

[@cartermason3275]

InstaBlaster...

[@karana2260]

Nice point! if its a completely random system like game of life, with everything and anything happening, wont there be a chance that characters will pop up with consciousness in all the randomness? Or to say high entropy states will occur.

[@krinodagamer6313]

yep

[@krinodagamer6313]

I just said that the day we can simulate a simulation where people or animals has self awareness then Ill believe we are in a simulation everything is based on quantum and binary codes

[@l1mbo69]

@@karana2260 you have misunderstood what a game of life is. It is NOT a random board where anything and everything can happen, there are simple rules for interaction in place

[@DeGebraaideHaan]

Your universe needs to restart to install important updates...

[@alarafatlemon3219]

LoL

[@william41017]

That was the KT event

[@irvingchies1626]

Dammit Microsoft, your effing update deleted most dinosaur files!!!

[@victorrielly9363]

So that’s why Big Bang.

[@AspLode]

Not now, Adobe Reader!

[@clairecelestin8437]

I appreciate that those with sufficient information storage and processing to answer the challenge question are awarded a prize proportional to their surface area

[@NaumRusomarov]

This is probably one of the more fundamental episodes as it shows that the universe might be informational in nature.

[@terryboyer1342]

I've always imagined our "universe" was just a junior high school kids entry for a science fair in the real universe.

[@alexeysamokhin9629]

Real?

[@mixnewton5157]

because you don't actually know how complex is reality

[@Adamzki55555]

If its that easy that person should also living in a simulated universe

[@matthewprovencio6020]

A goldfish in a bowl basically

[@terryboyer1342]

@@matthewprovencio6020 Or an ant farm.

[@Jordan-zk2wd]

Actually Switzerland is rotating, so a nonrotating neutral black hole isn't perfectly analogous to Switzerland.

[@TheNipSnipper]

reeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

[@ilxstatus]

Also, as a flat Switzerland-er, I find the analogy of black hole to Switzerland very offensive.

[@mokopa]

Switzerland does not rotate relative to anything significant, so, no.

[@youteubakount4449]

how can switzerland rotate if earth is flat...

[@insertdeadmeme]

youteub akount Switzerland can rotate because the earth is neither spherical nor flat but rather cylindrical

[@ToastedFanArt]

Dang that Switzerland dig was savage... Edit: For those that missed the joke, he said Switzerland was also "a non-rotating, neutral black hole".

[@shashankramesh6982]

Why did he say that? I didn't understand 😅

[@LoverKittey]

the roast is strong with this one.

[@fllthdcrb]

"Neutral ... again, like Switzerland". I'm pretty sure that was it.

[@ferdinandkraft857]

Now I know why LHC was built in Switzerland...

[@Quantum_GirlE]

love your pic!

[@matta5498]

If it's a simulation, thank God it allowed me to experience the 80's.

[@Therealwaweezy]

You must be a white dude!

[@antontomov8532]

@@Therealwaweezy You mean the admin. :D

[@rogerab1792]

and if it isn't, thank God/chance anyways

[@rashardmitchell7915]

The 80s was awesome 🥳

[@kamakirinoko]

No, I experienced the real 80s. You just experienced a simulation of the 80s. Thus, Sting. (And Michael Jackson).

[@wazzzuuupkiwi]

I really respect pbs's dedication to proper pronunciation. the amount of times I've heard "Swarts Child" over 'Swardz shild' made this episode refreshing

[@mattio79]

In a 1D world, are there Point-Earthers?

[@u.v.s.5583]

That's ridiculous. Everybody knows this planet is a finite open interval!

[@balrighty3523]

For that matter, in a 0-dimensional universe, are there "-1 Earthers"?

[@michaellv426]

Our Universe is a folded sheet of 2d space which is itself a folded 1d line of fixed-size points. At any given time, you can move on this thread only strictly 1 step left or right, but you can choose a step size from 3 options: x^0, x^1, x^2, where x is the length of one strand of this weaved space, equal to the length of the side of the Universe. By moving left or right by exactly x^0, you're moving left or right. By moving by x^1, you're moving back or forth, and by moving by x^2, you're moving up or down. So the Earth itself is a set A of several sets B of several line segments whose length varies from 0 to 12000 kilometers. Those segments are miraculously organized, i.e. lines of one member of set B are separated approximately by x^1, and those sets are separated approximately by x^2 on a universal thread, - that it gives an impression that the Earth is a sphere. While in fact it's just a mess from disjoint line segments, like everything else in this shitty universe.

[@cyberspore00]

mattio79 Pointless-Earthers

[@georgeabreu6392]

In a n dimension universe, are there (n - 1)ers?

[@EldafoMadrengo397]

That Anti aliasing line lol xD

[@Fittiboy]

What a horrible mess reality would be though :D EDIT: We'd probably have different standards of beauty. Either our own form of AA or just embracing the jank and looking like Minecraft skins.

[@amicloud_yt]

A bit of a groaner but a 5-star joke nonetheless.

[@side-fish]

But what about ray tracing XD???

[@alexjjgreen]

maybe turn off those ram hungry extra dimension visuals in settings

[@lwazishangase331]

NanoTree It just won't run without them. 😔

[@thstroyur]

Or install a GPU

[@HowBoutUHandleDeezNutz]

Visuals? Boi, 3 spacial dimensions and 1 of time are more than visuals

[@jardy3597]

Hey Matt. I think the fact that we cannot simulate the universe within our universe is dependent on one assumption. The assumption is that we need to simulate every atom. Which might not be correct per se. If we look at the Delayed Choice experiment, we can see that photon's paths are not calculated as if they are particles unless they are observed. I'm a Software Engineer, and if i had to write a program that would simulate the universe - that's the same thing I would do. I would abstract things into simpler items. So light becomes a basic wave that consumes an order of magnitude less computing power than if I calculated each photon. Same goes for all kinds of particles. Why do I need to calculate what each atom in a core of a planet is doing, if i can just simulate a planet good enough to not be distinguishable from a 100% simulation? Only when the particles are being directly observed, would I use 100% simulation, to hide the fact that it's a simulation. In my opinion, this will allow us to simulate the universe to be indistinguishable for the average observer, in real-time. Cheers.

[@ecicce6749]

If you do that your Simulation is not correct and lossless anymore and is very likely to become unstable over time

[@journey8533]

At the beginning of the video they say that you need to represent the quantum States, not the atoms. I believe there is a fundamental difference there.

[@Zithorius]

Ecci Ecci Just like ours. It is in fact theorized that over time a quantum fluctuation could rip the entire universe apart as causality continues onward.

[@akrybion]

@@ecicce6749 Maybe that's where Dark Energy comes in. It's actually the simulation losing accuracy (which simulating a certain amount of gravity somehow prevents).

[@jardy3597]

Will I? Light works exactly the way I described and the universe is just fine

[@ChrisBrown-pw2lb]

I dont understand half what is going on here. BUT I'M LEARNING! To everyone who worked on these videos. Thank you.

[@HowBoutUHandleDeezNutz]

Baby steps, 1 day it's Vsauce the next it's Isaac Arthur

[@HowBoutUHandleDeezNutz]

Even better

[@ParalyzedSociety]

Isaac Arthur is next level interstellar science shit!

[@u.v.s.5583]

One definitely learns much about Switzerland from this!

[@Midwesternreedneck]

we are going to need a better compression algorithm.

[@mememem]

What if the universe is pre-rendered? And/or compressed with lossy algorithms?

[@cholten99]

In a previous video I mentioned the idea of procedural generation. That way you could potentially generate the state of the universe with a much smaller amount of underlying data.

[@Alaric323]

Then the future and past can't be changed (because it's a CGI film in reference to a video game) and details similar to one another are ignored by the compression. ...which would explain dark matter because then a large amount of mass focused in a single area would be compressed into a single chunk, but the original interpreted it as spread out, affecting the spin rate of galaxies and the like.

[@Joiner113]

@@cholten99 surely this is represented in the notion of deterministic natural laws? If not, we have to imagine a "pre-rendered" world where some or all events are predetermined.

[@snbeast9545]

SST is a pretty lossy algorithm. And if the universe is pre-rendered, that'd imply two things: 1. We have no free will, and 2. This universe is, was, and will be the same as the one that rendered it.

[@markstanbrook5578]

SNBeast there’s no mechanism for free will in any physics, simulated universe or otherwise.

[@IanGrams]

Oh snap I got picked. Hi Mom! I will cherish the t-shirt immensely.

[@Erikulum]

"unfortunately you can only read out the simulation result... in hawking radiation" Made me laugh way too much

[@thstroyur]

There's C, Fortran, Java... but the real nerds program in Hawking++

[@CRASS2047]

It makes total sense and explains so much. Even explains and lends credence to the belief in a creator.

[@hoffmankspengineering2034]

I have a bit of a theory regarding a computational universe: essentially, gravity wells form around areas where there is a lot of mass and energy. The more particles are packed into a space, the more interactions happen between particles and thus the more information that is being processed. Now, (here is the part where I make an assumption) IF the universe has a decentralized computational bottleneck ( in other words, the more computation happening in a localized area, the slower it goes ), it would create a time dilation effect around gravity wells similar to what happens in relativity. Black Holes would then be areas where the computations are queueing up faster than they can be processed.

[@JohnGrahamsBlog]

Was the camera on Matt out of focus in this episode?

[@TheReaverOfDarkness]

No, it's actually the difference in travel time of the different wavelengths of light, as their speed is reduced by traveling through the air between Matt and the camera.

[@catcollision8371]

No, you're just watching the simulation on low settings, it's probably running on a low spec machine.

[@Deffcolony]

I think the simulation is running on a low spec MS DOS machine

[@zero132132]

If you can simulate the universe on a computer smaller than the universe, then can you simulate that simulation on something even smaller? It seems like the implication should be that the universe has limitless computational capacity if that's the case, but I don't get how that could make sense

[@ToyokaX]

I think that he mentioned that such a simulation would not include things like Dark matter and all that, so it's not a 1:1 simulation of the full universe.

[@Prospektism]

ad infinitum

[@jaredgraham4022]

Each subsequent simulation is simulated at a slower speed so if you keep simulating universes inside each other an "infinite" times over you'd approach computational speeds of "infinitely slow". So no it doesn't have infinite computational capacity.

[@timbeaton5045]

I thought the implication would be that if you could run that simulation, in a smaller space than itself, it would NOT be an infinite regress...sooner or later, the processing volume if it did reduce, would become a black hole.

[@noahhounshel104]

You could, provided you had the nessicairy memory, simulate the universe using an 8 bit computer. Its impractically slow, but we're already taking longer than the heat death of the universe to calculate to "last Monday" soooooooooooooo Its absolutely possible. Anything has "limitless" computational capacity so long as it can compute, but because its computational speed is much slower it balances out.

[@moofymoo]

3:20 - is it possible to make a doomsday device that downloads cat videos from youtube and stores it all in tiny region of space to make a black hole?

[@TheDuckofDoom.]

Tiny black holes are not significantly more threating than an equivalent amount of mass without black hole density. A cannonball and a black hole with the mass of a cannonball will have the exact same gravity at [and greater than] the radius of the cannonball. Tiny black holes also evaporate rather fast, so I suppose the next thought is how fast and will it grow or shrink, a 1000kg BH has a temperature of 1.2*10^20K and a lifetime of about 84 nanoseconds, even if formed at the surface of a solid rock and allowed to fall through the rock under earth gravitational acceleration it would evaporate much faster than it collected fresh matter and would quickly cease to be.

[@thetechoasis2179]

@@TheDuckofDoom. that is not true even a black hole of 1/1000th of 1mm orbiting our planet would tear it asunder

[@SonOfPepsi]

When I started watching this channel, I sort of had a grasp of what was transpiring, but with each new episode, I become more and more perplexed.

[@lawrenceshuda]

I love your humor! I enjoy chuckling while listening to you talk. I hope you continue these videos, for a very long time. Thanks.

[@colinfenn2517]

"Maybe if we turned off Anti-Aliasing...?" I'm dead. This line killed me.

[@RamzaBeoulves]

"That makes some intuitive sense" *Looks around* Yeah totally!

[@iseo247]

Why does everybody always assume our universe would be simulated from within itself, that would be boring for the programmers of that simulation. But what if our universe is being simulated from another universe with different laws of physics, e.g. maybe where the speed of light is faster, then it would be much simpler to do all those computations. :)

[@kyjo72682]

Exactly what I thought.. it could be much easier to run the simulation from one level up. We should assume only the necessary minimum about the potential simulator's universe. But from our perspective it doesn't matter how fast we would be simulated anyway. It could take years to compute a single frame of Planck time and we wouldn't notice. unless of course we were connected to the game from the outside. In that case we would notice the lag. ;)

[@badlydrawnturtle8484]

Indeed, I would argue that this whole ‘you need an absurd amount of computing power to simulate your own universe’ thing is true for most universes, potentially all of them. That would imply that any simulation would almost certainly be of a simpler universe than the universe the simulation is taking place in. It's not only possible that there would be a more ‘powerful’ universe simulating us, it's probable.

[@brokrokdale4909]

Infinity is too big how do you downsize it??? #Sciencethat

[@tomc.5704]

+Badly Drawn Turtle But it goes both ways. The universe above us is A.) much larger and more complex than our own and B.) also a simulation. Points A and B apply recursively. The only way to around that is to find a way to simulate a universe of the same complexity or greater than our own from within our universe,* or to accept that somewhere along the line there's a universe that's NOT a simulation. But if that's the case, why not this one? *I guess you could also claim that one of the parent universes has different laws of physics that allow them to accomplish this. That would certainly allow our universe to be a simulation, but it's a real cop out.

[@McMostaza]

Also consider that the sim could be slower than "real time", and we would never be able to know (not great for the operators, but maybe they are very patient) -- edit: video hints (?) at this, but more liberating with an unknown outside universe

[@LaughterOnWater]

By "Universe" we're of course talking about the observable. How do we handle edge detection in our model? Because whatever is outside the observable will still affect our model.

[@seerexplorer9578]

*_Thanks for having subtitles or captions_*

[@freesaxon6835]

Some very amusing computer related analogies

[@mathematicalninja2756]

Summary after reading the comments of this and previous video This universe is an algorithm/computation which finds the answer to the question of life, universe and everything. As soon as someone finds the answer to this question, the universe will cease to exist for that someone. The information stored in the universe can be approximated by the surface area instead of volume. This could mean some godly compression algorithm is being used and it increases the possibility that universe has everything precomputed. If the universe consists of set of precomputed states it implies two things: 1. We have no free will, and 2. This universe is, was, and will be the same as the one that rendered it. Also, the universe just needs to simulate the approximate nature of universe according to the observer instead of simulating everything. This greatly helps the universe in storing the information by a lossy compression algorithm. The lossy nature leads to noisy artefacts such as appearance of particle from nowhere and disappearing into nowhere which is basically birth and death. If an algorithm defines the simulacrum that is our Universe, then it is timeless... it just IS. The universe, the past, present, future has always existed and the observer experiences this "reality" until he finishes the computation of finding answer to life, universe and everything.

[@ToTheNines87368]

Wot..

[@davidwright8432]

'This universe is an algorithm/computation' - slight caution: it can be seen as this, but that doesn't oblige it to be so. It may be, but that's a separate question - which not every one agrees on (among those competent to make such claims). In fact, the universe is the universe, whatever that is.

[@paulponsford]

I have just found the answ

[@gstylez0107]

Great post, this guy's a real thinker

[@mykofreder1682]

A single 0 or 1 for each particle is not a lot of information, there is nothing about location and a lot of other important things. It's basically an inventory of one characteristic and does not seem like a simulation.

[@renzocalcagno6742]

No problem, my old Pentium will be able to do it

[@Toonj00]

My celeron can generate more than 2 universes at the same time!

[@Lexivor]

Ah, nostalgia. My fifth computer was a pentium.

[@irvingchies1626]

Pentium III is actually faster than pentium 4 in most scenarios

[@Soupy_loopy]

Is it just me, or are computers getting slower?

[@TheReaverOfDarkness]

Computers are getting faster, and browsers are getting slower.

[@cognozzle]

Funny that you should mention Conway's game of life. I always thought of it as an analogy for how physics work, or why they work in the specific way they do in our Universe, as if a deeper set of rules underlies why particles are the way they are.

[@Sa-fd7ih]

Matt’s narration is especially soothing in this episode 😄

[@WojtekWawrow]

Double hiccup at 8:39 - the 7 should be in the exponent with the 1, and the unit right next to it should be sec, not ops/sec

[@Twilumina]

Thank you! You have no idea how much it bothers me when sci-fi uses the term "dimension" improperly! Oh, and great episode, as always!

[@engizmo]

Yes the univerise is a computer and will always be while we keep exploring and defining it with maths. Surely thats no surprise?!?

[@IgorDz]

I only understood one thing - about defragging, and I feel proud!

[@knasigboll]

"And you'll never need to defrag again..." I haven't done that in ages. Thanks for reminding me!

[@GameCyborgCh]

*laughs in ssd*

[@svenvancrombrugge9073]

Hi Space Time! Thank you for the great video! I think you could save the information much more effective than you proposed (needing the Switzerland diameter black hole). Not to mention the possibility of compression you could save enormous amount of space by storing information implicitly, not explicitly. This might actually destroy the deterministic nature of the universe, but if you save emerging features, like atoms, or protons, etc. instead elementary particles. You could save a lot of space. Also if you can compute when e.g. a lightray / a single photon would interact somewhere. You would not need to save and compute it for billions of years, only store it compressed in a storage, that waits for such interactions. Especially computation wise this would make a huge difference. I don't believe in the "single electron" idea, but this idea kinda aims in that direction for other features.

[@lawrenceworrell591]

Really. Reeeeeaaaally. Good luck searching that entire space for the single interaction. You'd also have to know in advance that particular piece of data is needed for decompression and data search. But then you'd have to pull it out regularly and compute it's next steps then put it back then pull it out, compute put it back. You'd have to resolve the entire universe on each clock tick. Otherwise things like Oumaumamamia ( can't remember the name) wouldn't appear unless they are hand crafted occurrences.

[@priyapramesi6026]

I'm confused...wouldn't simulating the universe with something smaller and running faster than the universe itself lead to paradox? That means if you have simulation of the universe inside itself, you could build a computer that simulates the universe and itself, which then recursively simulate universes (and itself) infinitely. Wouldn't that require infinite storage space? Same problem arises when the computer is able to simulate the universe faster than the universe itself. If the computer is running faster than the universe, let's say by only 0.0001%, the computer can then simulate itself recursively and infinitely, making the speedup infinite (because then the future will have already happen in the simulation), which is a contradiction. Like let's say a computer can simulate arbitrary physical process that takes 2 seconds in real time in only 1 second. If it simulates itself, then after 1 second, the simulated computer will have ran for 2 seconds, which itself has simulated a simulation that ran for 4 seconds, ad infinitum. But that's a contradiction, because the original, physical computer can only simulate physical process in half the time, not infinitely. Am i missing something here?

[@danbaurceanu129]

No. This whole thing is one untestable wild speculation.

[@frankguy6843]

You're right, this is pretty much nonsense, an entertaining video but it approximates and estimates so much it doesn't make any real conclusion.

[@rubiks6]

As far as the size paradox goes, I agree with you completely, Priya. I also saw the problem, almost immediately. It seems so obvious. I'm really don't understand why Matt doesn't see it.

[@johnreza8746]

'If you assume the universe is evolving at the maximum computational rate' -- I believe the correct interpretation of this is that with a universe simulator that simulates at a rate much faster than the universe itself the simulation must always end up having less fidelity than the actual universe.

[@wasd____]

No, it doesn't lead to a paradox. The computer isn't simulating itself within the simulated universe, and the universe doesn't contain the maximum density of information (because if it did, it would be a black hole), therefore there it is possible to simulate a universe the size of the one the computer is in on the surface area of the event horizon of a black hole smaller than the universe itself.

[@TusharSharma-km3bt]

If universe is a computer , there must be a way to clear the RAM (decreasing entropy)

[@regularsense]

coronavirus)

[@xenithmusic3029]

Although we are dead the same amount of matter exists. Data cannot be removed.

[@melissawhite5116]

Not without breaking the rules. Nothing is ever lost...ever. it all breaks down if information is lost.

[@benbennit]

You only measure what you require during a microscopic slice of time.

[@Okuni_]

i can barely understand things these channels has spewed out over the years but i still watch it

[@albertgerard4639]

The animations in this video where extra super awesome

[@CinemaRockPizza]

You are off focus, dude - in that case you seem to be not fully rendered...

[@vincentlevalois]

I checked my res settings to make sure I wasn't in 144p.

[@Spiralem]

Graphical fidelity is sacrificed to compute the universe.

[@starscape539]

Quite understandable. After all, they only have the surface area of the universe to store the full volume of the computed reality of the universe.

[@aeropasta]

do you wear glasses?

[@ichbinein123]

He's off focus in every video. A bit annoying to be honest, considering their otherwise amazing production value.

[@H4kkk0]

The Line Earth conspiracy theory starts here now boys ! Let's go spread the word !

[@stuffums]

I'm writing down my dream life scenario so when I die there might be a small chance I can chat with a simulator tech and ask to be put back in as this character.

[@nolanwestrich2602]

Hey God! Reincarnate me as a celebrity!

[@SuviTuuliAllan]

Isekai protagonist volunteer #3 here!

[@TheBackyardChemist]

Not a good idea, someone did that ~2000 years ago, and look where that lead

[@badlydrawnturtle8484]

What's the likelihood that someone running the simulation would pull out your code and reactivate it to talk to you after you die? It's not like people go around asking video game characters how they feel.

[@stuffums]

Like 1 in a quadrillion chance but better than 0, and I'll also request all weebs can be sent to a parallel simulation where Anime is real

[@willypataponk]

I love this channel! You manage to explain very complicated things in a "simple" way. Keep up the good work!

[@zodiacfml]

11:26 I agree. We already are applying/using these in the real world, computer virtualization or virtual machines. Virtual machines can never equal its host in terms of compute/storage.

[@MsBobZero]

Could you make a video about communication/internet in deep space? I can’t find a lot about it on youtube. I’m wondering for example; how much time does it take to send a message from pluto or voyager 1 to earth? Love your channel by the way!

[@Aidan42781]

I don't think we'll be stimulating universes atom by atom anytime soon but shouldn't it be possible to simulate smaller regions of space? Maybe a planet? A Solar System? Let's say you simulate the Earth in precise detail down to the last quark and gluon but simulate the rest of the solar system in much more crude detail. Then you simulate the rest of the Galaxy and universe in even cruder detail. Doesn't really matter if X Nebula light years away is just a fairly simplistic particle effect as long as any simulated life forms that develop don't develop near-light speed travel. We can take that one step further and say that we make some kind of algorithm so that finer details only render if something observes it. ... Wait a minute.... Nah, until the simulation hypothesis has a reasonable way to be tested it's largely irrelevant. But it's also interesting to talk about because I think there would be value in us humans simulating 'chunks' of universes. For instance, simulating the Solar System and seeing if it spawns life and how that process takes place.

[@AbsoluteArch]

You must also program the way every atom reacts with it's surrounding because any mistakes at the atomic level will scale into the larger image and change the results of a simulation. Most programmers rely on prewritten algorithms that mimic real life physics of motion, but that wouldn't work on a universal level.

[@danieljensen2626]

Since the universe contains tons of black holes wouldn't you need to add all the black hole masses to those figures you came up with to actually simulate the whole universe, including black holes?

[@scotthammond3230]

This! How can you fit the universe into a galactic black hole, when you also have to include all galactic black holes? This makes no sense. You cant pack black holes tighter.. they just get larger. Does the 10^80 H count come from the initial big bang, or is this the current count excluding what has fallen into black holes? Second, if you dont include black holes in the universe simulation, this means that current galactic black holes have enough information inside of them to actually be separate universes.

[@MegaFonebone]

I think I can actually answer this one. The reason black holes don’t add much to the storage requirement or computational complexity of the universe simulation is that, informationally speaking, each black hole requires no more information (parameters) to describe than a single elementary particle. Just 3 parameters, in fact: charge, spin (angular momentum), and mass. If the “no hair” conjecture is correct, anyway. We’re not talking about fitting the actual mass of a black hole into our memory storage medium (which happens to also be a black hole, just because we’re visualizing the minimum possible space needed for all the information). We’re only fitting the information needed to completely describe a black hole. See, I can store all the information needed to completely describe an entire hypothetical Swarzchild black hole right here: {0,0,42}. The first parameter is the black hole’s charge, i.e., it has no net charge. The second parameter its angular momentum, i.e., it’s not spinning. The third parameter is its mass in solar masses.

[@danieljensen2626]

@@MegaFonebone Clearly you haven't been watching the rest of the videos in this series... Current theories suggest black holes retain all the information of every particle that ever fell into them and this information is imprinted in the Hawking radiation. Thus to simulate a black hole accurately you basically need a copy of that black hole or an even larger black hole.

[@zodiacfml]

They are somehow correct because black holes don't do much in the universe once it captures the particles inside. It's like a drawing a black circle in your computer program which is simple to do. The video only considered visible matter in the universe an approximation of the real universe, kindly like throwing out some information from a CD quality audio, turning it to an MP3/lossy compression file. However, I can argue that black hole mergers spread out a ton of energy through gravitational waves

[@danieljensen2626]

@@zodiacfml I'm pretty sure storing your simulation inside the big bang is cheating, haha.

[@georgehugh3455]

Makes sense - _the Heisenberg Uncertainty Principle is just the computer's way of interlacing for a faster refresh rate_

[@markmiller4414]

This episode reminds me of one of the first ever CG movies in the 1980s, The Last Starfighter, where we discover a space video game was placed here on Earth by an alien civilization hoping to find a high enough scorer to become a "starfighter". I wonder if Matthew O’Dowd and PBS SpaceTime are really space aliens trying to find the next Einsteins to solve their way out of a universe-ending cataclysm ;)

[@Ryukachoo]

6:15 What the what? Did the EHT finish it's work way faster than I thought or is that a heavily tweaked cg rendering based on little data

[@Vinniewashere]

that's what I thought. made me wonder if since matt is a scientist and in the business they can get leaks of unpublished images would be sweet but the more logical explanation would be it's a rendering from EHT

[@watsisname]

It is a simulation of what an accreting black hole like SgrA* might look like, run by Hotaka Shiokawa. You can find many other simulations on the Event Horizon Telescope project's home page, as well as here on youtube. :) Running these simulations helps the scientists understand what to look for in the real data and how to use them to test general relativity's predictions.

[@nnnn65490]

If you can simulate the universe with a computer smaller than the universe, can I simulate minecraft in minecraft with a redstone computer?

[@andreys7944]

>If you want to include photons, neutrinos, dark matter, etc. Does it include black holes larger than Sag. A*?

[@dogwaffles]

You have to find the perfect balance between getting your mind blown and not understanding a word to keep up with this channel.

[@luci75d76]

Ok. This rime you Really blow my mind. So many factors !

[@ghyslainabel]

Question unrelated to the episode. 1- We know the universe is infinite, or at least big enough that we see only a part of it. 2- There should be as much matter as antimatter. 3- We do not see a frontier where matter and antimatter annihilate each other. So, is it possible that the distribution of matter and antimatter is uniform only in the largest scales, and we just just happen to be in a place where the frontier between our section of matter and outside antimatter is outside the observable universe?

[@xhelloselm]

It would be strange that everything else we observe is very evenly distributed even across the observable universe while antimatter is not and only even across larger scales. But sure, in principle everything is possible.

[@timothymclean]

Is it possible? I suppose. But AFAIK, there's no reason to think that the discontinuities should be that large. If a theory was developed which had that as a prediction, and its other predictions bore fruit, we might solve the problem. Until then, it's just more speculation to throw on the pile. (Also, we don't have any clue how much universe there is beyond the observable.)

[@ghyslainabel]

Unaussprechlicher Name, I expect there was a lot of annihilation in the first few moments of the universe, and the gamma rays produced are lost in the microwave background by now. The only matter and antimatter left would have been in separate pockets to still exist today. The initial annihilation would explain why the distribution is not as even as everything else on smaller scales.

[@tabularasa0606]

What if the anti-matter is just moving in negative time.

[@ghyslainabel]

Timothy McLean, of course it is only speculation. But I have to ask, how certain are we that the universe should be exactly the same as the observable part we are in. I sometime wonder if we are doing the same mistake on larger and larger scale: the Earth is the centre of the universe, the Sun is the centre of the universe, the observable universe is an accurate representation of the whole universe. If someone with a physic background could prove me wrong, I would be happy to read the explanation.

[@JustForComments666]

Is it possible possible that this universe is inside the black hole of a 4-dimensional reality? Like you explained in one video (penrose video I think) once you are in a black hole one direction becomes time. So could it be that inside the black holes in this reality there is a 2-dimensional reality and inside the black holes of that reality there are 1-dimensional realities? Like a never ending matryoshka of dimensions. Also, how is 1 bit per particle enough? Don't you need more than one variable to define position and momentum?

[@akashchandrabehera7667]

But sir the Margolus-Levitian theorem says that max. No. of Ops/sec a system can perform is ≤ 4E/h, thus if our black hole simulator starts to perform Ops then it's speed (i.e. Ops/sec) must decrease as the energy of the black hole decreases and it becomes smaller, so One must integrate the expressions rather than just division. Also you said that output will through slow Hawking's radiation but the output shall be transmitted immediately as the black holes performs Ops and loses energy. Why is there a time lag when the computation is taking place on event horizon (where the Hawking's radiation originates)?

[@lawrenceshuda]

This was a crazy video! I did enjoy it.

[@LordMichaelRahl]

Didn't know about some of these principles, thanks PBS.

[@pierreabbat6157]

Why did the universe simulation crash? The programmer forgot to initialize the Cepheid variables.

[@tomf3150]

Constants aren't, variables don't.

[@vovacat1797]

"A non-rotating neutral black hole... Like Switzerland"

[@v.sandrone4268]

matter (gold) enters Switzerland and information never leaves it just like a black hole.

[@edemilsonlima]

This universe is expanding because of an endless loop that is filling up memory in God's computer.

[@TheFlyingTVsNOW]

And thats why only the ones God remembers will be saved. Only confessing you're sins to Jesus and asking for forgiveness will save you. Amen

[@regularsense]

buffer overflow = coronavirus

[@raptecclawtooth9046]

This universe is a troyan!

[@PoppyB2011]

@@TheFlyingTVsNOW Comment brought to you by the Onion.

[@EMan32x]

I love this channel so much.

[@SoraHjort]

my 2 cents on the whole Dimension vs Universe terminology. What sounds better: Inter-dimensional travel, or Inter-universal travel. And that would probably help explain why people mistakenly go with dimension. That and one might make an argument, whether correct or incorrect, that another universe is just another dimension (macro-dimension?) of the multiverse. Where each universe is a dimension with it's own collection of individual and shared layer sub-dimensions.

[@gb-nz]

Let me roll one and watch again

[@Sound_.-Safari]

I'd love to know the implications of theoretically computing a smaller universal simulation wherein the scope of the computation is only for a small area of the universe? Could you possibly outpace the computation of the real universe but only for a subset area of it?

[@mixnewton5157]

no it can't outpace, or even be as good as the universe, the problem with this video is not simulate the black holes, also having a lot of assumptions and over simplify the reality, we actually don't know exactly if the space-time is actually quantized or not

[@MeinDeinSeinCraft]

0:33 this is not full HD! Is the camera out or focus or what?

[@alice_in_wonderland42]

yes

[@nachannachle2706]

Switzerland = "a neutral blackhole". Thanks for the new definition! :) PS: The universe is a simulation: Karma gets you reloaded as soon as you evaporate.

[@SilverCloudMusic2012]

Hollywood dose need to hire spacetime to get the science right.

[@ByrnesPCGarage]

What if you only have to compute something when a person, or being is observing it?

[@martiddy]

It may sounds weird, but that's probably how our universe works, with observing I mean that the particle exist until it interacts with other particle (like barionic particles or photons)

[@NeoFryBoy]

Wouldn't something need to check if anything had observed it? Sort of like the Halting Problem.

[@ΔημήτρηςΤσαγκέτας]

Thats why in quantum mechanics a very small particle does not exist somewhere in space until its observed. Before that the particles Location is just a probability in space. I think "god" decide very small objects to behave like that just to save memory. Its more efficient in the simulation

[@BlueFrenzy]

NeoFryBoy, right. So in order to prevent checking every particle, we define a maximum interaction distance like... the speed of light. But, wait, if the mass is too dense it will still take a lot of time to compute, so... things lag and move slower.

[@HowBoutUHandleDeezNutz]

Good question. too bad many seems to take it out of context

[@markfudge5642]

If a computer creates a universe, Isn't it then a universe ?

[@DanielDogeanu]

Indeed. Maybe this is exactly what we are. A simulation of an highly advanced civilization trying to figure out their own Universe.

[@markfudge5642]

As long as we are not in an advanced version of The Sims.

[@burnhamist]

Microverse

[@ovidiudans]

Teenyverse

[@LyubomirIko]

Or we are the escaped souls of entities that have lost its own Universe due to heat death of their Universe

[@UserAnonymus1995]

What if you take a small volume and make a fractal-like 3D shape out of it? We could get a way bigger surface area than what we’d get by shaping that volume into a sphere. Would we also magically be able to store more information in that volume?

[@ferdinandkraft857]

Annie - nope, that's not the way the Bekenstein bound works. Check its wikipedia page.

[@aeropasta]

Triply-Periodic Minimal Surfaces

[@IterativeTheoryRocks]

What about all the existing black holes? Surely this super computer must be at least the mass of the sum of the masses of all existing black holes?

[@Kazemahou]

I regularly play No Man's Sky. The game provides 16 galaxies, each with 14 quadrillion planets, orbiting suns in discrete starsystems. The planets have moons, some have oceans, those with life feature every kind of plant life in every sort of biome, animal life ranging from gargantuan beasts all the way to tiny butterflies, little fish to whales, birds and bat-like... things, and more besides. There are countless forms of geology in play, types of minerals, a unique periodic table, and at least four intelligent starfaring species. Additionally, there are outposts, buildings, trading platforms, space stations, and more. Fleets of ships ply the starlanes, yet you can sit by a river and watch a single flower dance in the wind, and study the petals on that flower. It uses procedural generation to achieve all of this, and it does so in only 10GB. Ten gigs. Maximum. And it keeps track of the things you build, name, and change, including the ditches you dig, the rocks you break, and the trees you cut down. The question presented by this episode is not answered with understanding of what is possible. Yes, it is possible to simulate an entire universe as stated - but by using procedural technology and by limiting computational resources purely to generate what actual, conscious beings perceive and interact with, the requirements to simulate a completely believable and immersive universe become trivial. The beings inside of such a simulation can have their science experimentation likewise procedurally generated such that, when investigating the smallest things, such things only exist as discrete phenomena during the moment of their actual observation... and have no representation outside of that context. Science would report a complex, detailed, and real world, yet the simulation requirement would be trivial compared to simulating every single particle all of the time. The number of possible simulated universes even using the most basic of procedural methods would be... literally astronomical, and economical as well. Bostrom's argument is well supported by just how easy it is to manufacture a universe of any desired depth and apparent complexity using modern procedural techniques.

[@UpcycleElectronics]

14:57 Toe the line Matt. Toe the line.

[@todmann67]

I was hoping someone else saw that.

[@Btkmersajt]

What can we know about the universe at the time when it was smaller then the 10 million kilometer black hole, after the big bang? Was that still part of inflation period? How could its information content be described, on a surface area smaller then the Bekenstein bound? Oh wait, I might have figured it out by the time I typed the question. Is it not really a problem since the early universe had very low entropy, and didn't require the same number of bits? But that would mean that the information content of the universe is increasing over time... Now I confused myself. Help please?

[@tomc.5704]

I think what you've done is shown that we don't have an absolute answer. That said, if anyone out there has a theory that might help, I'd like to hear it too.

[@williamwaldrop2890]

You almost had the answer I think. Because the entropy of the universe is increasing from this initial minimum after inflation (2nd law TD) the information the universe contains increases. This is represented by the size (surface area) of the observable universe increasing over time.

[@williamwaldrop2890]

Ignoring the expansion of space (since this value is variable over time and the current value is in debate) the observable Universe can be defined as the light that has had time to reach us. The more time we exist, the more light reaches us, the more of the Universe is observable and the more information it contains. The expansion of space does limit this at the point where it expands faster than light but again where this is being debated. As far as the 'Universe proper' it is my understanding that the current theory is that it has no boundary (finite without boundary).

[@Btkmersajt]

@@williamwaldrop2890 it's a good point, I meant to say observable universe. It makes sense then that the observable universe gains more information over time. But the original question still stands: what happened to the observable universe after the big bang, when it was smaller then its corresponding Bekenstein bound? By definition it should've became a black hole, right? But that's not what we see, so what was different then? Bonus question: is the Bekenstein bound somehow related to primordial black hole formation?

[@williamwaldrop2890]

@Bence Mihalka, Remember that the amount of entropy is a measure of the information needed to describe a closed system. The Universe after inflation had its lowest entropy and needed less information to describe it so the Bekenstein bound was smaller than would be needed at our present point in time. You can also think of our 3D space as being the surface of a 4D black hole where the surface area of the 4D BH is the Bekenstein bound of our 3D Universe so we could be living at the Bekenstein bound in 4D space

[@StanTheObserver-lo8rx]

I notice too..you back up what I have said for years..its that black holes dont tear "the fabric of space" or engage in weird faster then light time travel. They just compact matter in a way we dont understand yet. To them Plank lengths are foldable you might say. I mean,If you could compress the image on your TV screen..its not going to take up much room. How "thick" is an image? or Shadow,maybe? Something philosophical like that only with real numbers.

[@zodiacfml]

You're so timely, again. I've been pondering this on the concept of space. Space seems infinite and that it could be just built with Math or compute.

[@CanorousFlatulence]

Does this mean that sagittarius a* has as much...stuff in it as the entire observable universe has matter and radiation? Roughly speaking, of course.

[@lamacat]

This is what I was wondering as well. Surely you couldn't store all the information of the universe into a space that size when there are countless bigger black holes that would require their entire surface area to be described

[@estranhokonsta]

You do not mention the fact that such a simulation would necessitate a deterministic universe, which contradict the actual quantum theories and would give strength to the hidden variable theories. How would it simulate the states of the particles with the 'computational schrodinger bug'? If it follows the same constrictions that quantum uncertainty gives, them the simulation would be very poor. One more thing: a simulation does not equate to the simulated.

[@photios4779]

I can partially agree in the sense that our universe could not possibly be simulated on any "Turing machine," which is the basic computational paradigm describing all our existing computers. But a non-Turing quantum computer could replicate quantum behavior in a simulation. You're absolutely right to point out that "a simulation does not equate to the simulated." Assuming the premise is correct, the computational environment in which the simulation runs could operate under completely different laws of physics in a reality that is radically unlike our own.

[@gutterball10]

you'll never have to defrag again. turn off anti aliasing. the proton would decay by the time you simulated last monday.

[@KrustyKlown]

If we evolved from a computer simulation, why are there still computers? (humor)

[@feynstein1004]

Is it me or is Matt out of focus? Camera guy, you had one job, bro.

[@feynstein1004]

+ryoriotwow Lol you don't say

[@MinecraftBoy-bj5bn]

The simulation is glitching

[@sweethater8558]

Three, he had to make sure it's recording.

[@royriley6282]

He's being run at a higher planck length in order to cut down on processing power.

[@Alorand]

Subtitles/CC: Dutch (auto-generated) ...sigh

[@big0medium]

Ha, baby handjes

[@luisjimenez5953]

I thought dutch people were basically bilingual, why would you need subtitles

[@bzuidgeest]

Nederlandse ondertiteling? Ik ben een Nederlander en ik heb die nergens voor nodig. Als je goed Engels leert gaat er een wereld voor je open. Mogelijk ben je doof, maar gebruik dan de Engelse ondertitels er gaat namelijk altijd veel verloren in vertalingen, de hoeveelheid fouten in ondertitels is een hoofdreden om ze niet te gebruiken. Ik wou dat ik chinees of Russisch makkelijk kon leren, maar dan heb ik nooit meer genoeg tijd om alles te lezen en zien :)

[@rcagamaz]

it is probaly because most english words are also valid in Dutch due to borrowing and a common ancestor "was" and ''is'' for example have exactly the same meaning in both languages, so is goal and computer

[@XEinstein]

@Luis Jiménez: I find that offensive. We're trilingual at minimum! 😉

[@PoppyB2011]

I love how the only thing we can do to attempt to conceive of something like this, is to relate infinite possibilities to present knowledge. We talk about this as though the programmer is still running Snow Leopard on a Mac. We can't conceive of something that could generate and maintain a universe. Think about the operating system it would need, and the storage to hold... let' s say human ignorance. That's huge.

[@possumverde]

Cutting corners on processing could explain a lot of the weirdness of our physics. If a simulation didn't need to be accurate at the extreme small and large scales, it could just be approximated/truncated to save processing power. That might explain why quantum physics appears to be probability based to us and the infinities we get from singularities etc.

[@Shinlung66]

The entire universe is way larger, the observable universe is just all that has rendered so far ;)

[@morganwardfilm]

This is exactly the video i was looking for. Thank you!!

[@alpha7158]

If the Margolus Levitin Theorum puts an upper limit on the speed of quantum interactions that is proportional to the amount of energy, then surely this would feed heavily into a quantum gravity theory? More mass resulting much more energy resulting in slower quantum interactions. Therefore the closer you get to a massive object, the slower your quantum clocks can run due to the energy of the system around you. And, and the universe grows in size, the faster the computations can happen in regions with no energy. This would result in faster computations in massless regions, which could explain dark energy.

[@jaredgraham4022]

At ~7:10 in the video, he seems to state that a quamtum system evolves faster when there's more energy. That seems the opposite of your statement that "the closer you get to a massive object, the slower your quantum clocks can run."

[@ObjectsInMotion]

You're confusing the words "proportional" with "inversely proportional". If the upper limit is proportional to energy, more energy means high upper limit and faster interactions.

[@holeytrolley6094]

Nerds

[@alpha7158]

@@ObjectsInMotion ah yes, thanks. You are right.

[@alpha7158]

@@jaredgraham4022 ah yes, you are right. Thanks for spotting that.

[@KangHyunChu]

Is there a universe-simulation going on in the universe simulator? moreover, can we make a universe simulator in a universe simulator in a universe simulator on and on and on..

[@NonDelusional74611]

Kanghyun Chu some will call it a Miniverse. Some will call it a Teenyverse.

[@darealg6823]

Universe simula-ception

[@zodiacfml]

Yes. It computer science we call it a Virtual machine inside a virtual machine

[@thenoseplays2488]

In a perfectly modeled evolutionary simulation of the universe...we would once in for all prove some equation of variables could produce sentient life without the need for god...only to look down at our creation and see those sentient beings arguing over whether or not we exist.

[@KohuGaly]

That's why divine creation is technically just special case of simulation hypothesis and thus by definition no more likely.

[@alarafatlemon3219]

Well how this evolution happens also need god like you program a chess game to learn it self and this program became master in chess game but this evolution never happened if you don't give specific rule. You see even evolution need god. LoL

[@Ennar]

The problem with people arguing for the existence of god is that they consider elementary school level analogies to be compelling proofs. And then they wonder why nobody takes them seriously.

[@alarafatlemon3219]

@@Ennar please I want to see your analogy

[@Ennar]

Here's one that you could have easily extrapolated from my previous post. The people that argue for the existence of god make arguments like elementary school children. Therefore, their conclusions are to be taken with the same seriousness.

[@sirdgar]

You explaian everything so well...thank you….cheers

[@javihache8066]

Please let me know if I am saying something absurd. However I cannot stop thinking of the quantum nature of spacetime. It's like digital sound or image. We consider sound as a continuous wave but to process it digitally we take samples at equal intervals and give them a value (in any case there's no continuous nothing in the universe). You can rebuild it fast and get to play the sound as it was originally. Could the quantum nature of spacetime be a consequence of our universe being simulated? Planck time could be the interval at which our universe is sampled and planck length the the resolution in space of the universe. That's the frame rate at which the whole game is being played.

[@armagetronfasttrack9808]

This is such a contrived and backwards argument. First give an estimate for the information necessary to describe the Universe that is way smaller than the Bekenstein bound (because of a confusion between a single configuration and the state space) to then use the Bekenstein bound to claim it can be crammed into a BH smaller than it? The statement that results, that you can simulate the Universe in a computer smaller than it, is wrong and in clear contradiction with the BB. To simulate a system, you should be able not just to encode its current configuration, but any possible configuration. That requires an amount of information that is given by the saturated BB. So to simulate the Universe on a BH, for example, if you want to minimize computer size, then the BH has to be as big as the Universe. P.S. I would also add that counting up the info in radiation and matter is also a severe underestimation of the information in the current state of the Universe, as it is actually dominated by far by entropy of black holes. It really doesn't matter though, because again the information encodable in one state is meaningless; what one needs to process to simulate is the information that distinguishes a particular state from all the others, which is S_BH >> 10^90. Original comment (not me) from: u/rantonels on /r/Physics www.reddit.com/r/Physics/comments/9ogo3e/computing_a_universe_simulation_pbs_space_time/e7vfpie/

[@gizatsby]

If a computation of the universe could outrun its actual evolution, wouldn't you run into causality violations anyway?

[@HowBoutUHandleDeezNutz]

Oh man, ur on another level

[@AngelLestat2]

No.. you are just changing the speed that the universe develop, you can render an image with a slow computer and require 1 hour or you can do it with a faster computer and require 1 second. The time of the process does not change the final render.

[@gizatsby]

@@AngelLestat2 But you could theoretically use the information from the render to change the outcome in the "real" universe, couldn't you? And assuming it's a perfect render, it has its own simulation inside of it, so it wouldn't be the presence of a simulator that caused the discrepancy. You could have information about distant parts of the universe (or from distant times) influencing you, giving rise to all the paradoxes that come with causality violations.

[@AngelLestat2]

​@@gizatsby only if you are outside of the universe and change the universe according to that (which is cheating or changing the rules of that universe), in that case you are the god of that universe. But that is not possible for anything inside the universe. not sure if I am explaining this well enough, the speed of the calculations is not related to the speed of light that you determine for that universe. You can calculate at hand certain particle path and interactions or you can use a computer, but the speed of calculation does not change the result, only the parameters can change the results. I remember old games from the first PCs which their game engines were bad designed, because some used the clock speed of the computer as global parameter of time, so when you pressed the old "boost" button to increase the frequency of your chip, the whole game run at higher speed, but that is just was bad programming.

[@gizatsby]

@@AngelLestat2 Back up a bit. We assume a deterministic universe (at least on the macro scale). This is a perfect simulation because it contains all the information about the universe in a compact form. This means that if it's possible to start with the same initial conditions, and if it's possible to run the simulation faster than the universe evolves, then it's possible to have a simulation that predicts the future. If it's possible to "watch" this simulation (or otherwise extract information), then you've can receive information about distant spacetime faster than any physical causal connection like light. So let's say that Bob is watching the simulation. If Bob sees his simulation self get up in 5 seconds, then he could theoretically choose to NOT get up. This would mean the simulation guessed wrong, and was not a perfect simulation. We've reached a contradiction, so one of our assumptions is wrong. My guess is that it's physically impossible to set up a perfect simulation of the universe within the universe that still runs at the same speed or faster than the outside universe (probably for the reasons related to the video).