[HN Gopher] Four billion years in four minutes - Simulating worl...
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       Four billion years in four minutes - Simulating worlds on the GPU
        
       Author : diggan
       Score  : 292 points
       Date   : 2024-07-29 23:33 UTC (23 hours ago)
        
 (HTM) web link (davidar.io)
 (TXT) w3m dump (davidar.io)
        
       | shanxS wrote:
       | Sometimes I wonder what it'd be like to live in simulated
       | universe.
        
         | dylan604 wrote:
         | You say that as if you aren't. What proof do you have either
         | way?
        
           | TheHumanist wrote:
           | Pretty sure all of you are in my simulation... Right? Or
           | maybe I'm just in a coma and this is a coma dream...
        
           | senectus1 wrote:
           | why does it matter?
           | 
           | If we are, we're in a sandbox that cant be escaped. live your
           | best life and get on with it
           | 
           | If we aren't Live your best life and get on with it.
           | 
           | I've never seen the point of the question.
        
             | dylan604 wrote:
             | Sometimes people like to exercise their brains with random
             | what-ifs. I've never seen the point of people that never
             | let their brain wander.
        
             | andersa wrote:
             | What if we _could_ escape the sandbox? Our software has
             | crappy exploits all the time, why wouldn 't theirs?
        
         | jagged-chisel wrote:
         | "I don't know, Timmy, being God is a big responsibility"
         | https://qntm.org/responsibility
        
         | bilekas wrote:
         | When thinking about this one, I always wonder if it even
         | matters.. playing both "Yes" and "No" scenarios doesn't really
         | offer any insight for me. Maybe it's a degree of nihilism but
         | it makes me not get overwhelmed.
        
           | cout wrote:
           | A simulation has a nonzero chance of having exploits, and
           | it's debatable whether it is in our best interest to discover
           | them.
        
             | heyitsguay wrote:
             | What's an "exploit"? Is electricity an exploit of that
             | weird phenomenon where a balloon sticks to a wall
             | sometimes?
        
               | koudelka wrote:
               | I'd imagine that's an application of a rule, whereas an
               | exploit is a violation of a rule that allows for (a &&
               | !a) or some such inconsistency.
        
               | brunokim wrote:
               | God created electromagnetism as a way to transmit power
               | between the fusion plant and its simulated planet, and is
               | now delighted that we also use it to trade Pokemons back
               | and forth.
        
             | bilekas wrote:
             | I consider biting my tongue when eating a glitch in the
             | matrix. If there's a higher level exploit, I definitely
             | don't wanna know!
        
             | mensetmanusman wrote:
             | Consciousness is the exploit.
        
         | candiddevmike wrote:
         | Watch the show Pantheon sometime! No spoilers, just highly
         | relevant.
        
           | MaxikCZ wrote:
           | That series blew me away, both seasons, every episode is just
           | totally awesome. Hard to reccomend without spoiling.
        
         | ffhhj wrote:
         | The Universe tries its best to catch up with Math. So, Math
         | isn't fully simulable by the real?
        
         | beepbooptheory wrote:
         | What's it even like to live in a non-simulated one!
        
         | dheera wrote:
         | The energy and matter in the universe is actually a big analog
         | quantum computer simulating the result of a set of equations.
         | 
         | Nobody said the simulation had to be run on semiconductors.
        
           | thfuran wrote:
           | It's less commonly said, but the territory isn't the map
           | either.
        
         | xwolfi wrote:
         | Well you are in a way, what is a simulation ? It's just a set
         | of rules you follow that are simpler than the more complex
         | environment that it runs in: I suppose if we could "see"
         | "outside" the "universe", we'd understand that maybe our
         | reality is very simple and limited compared to the "reality"
         | outside. Maybe this would be true infinitely, or maybe the
         | outside reality would be much more logical than ours, and we'd
         | accept it's finite.
         | 
         | But since we have a beginning, and a flow of time, we probably
         | also have a birth, a mother, and maybe even a purpose... but
         | that's a very human way to think, might all just be random
         | soup.
         | 
         | But imagine there's a self-aware agent in a simulation we
         | create, he starts thinking the same thoughts, everyone mock him
         | "we're all just random, there is no God, no design, how could
         | so much energy be spent on such a useless giant block of empty
         | space for any reason", he would have to sort of agree, but he
         | would be sort of wrong. And discovering us, would bring him no
         | solace: we can't tell him of our own designers ourselves.
         | Discovering them, would bring us no solace either, for the same
         | reason. That's why the concept of God is stupid: God has a God
         | too, so what do we do now, solved no problem to accept His
         | existence.
        
           | mistermann wrote:
           | I think modern people have so much faith in this reality,
           | they'd have little chance accepting that it is other than it
           | seems. Any evidence would have to be _stark_.
        
             | melagonster wrote:
             | Actually, physics supports the probability that we live in
             | a simulation. Our universe has the highest limitation of
             | speed and the smallest units of length and energy.
        
               | mistermann wrote:
               | Neuroscience, psychology, public opinion polls, and
               | internet forums _demonstrate_ that we do.
               | 
               | The problem is, the nature of this _style of_ simulation,
               | as opposed to the Bostrom theory ( "the" simulation
               | theory (singular, _there can be only one_ )), makes it
               | (nearly) impossible to realize.
               | 
               | This is both tragic and hilarious, especially since we
               | have extensive knowledge of this flaw.
        
           | mensetmanusman wrote:
           | That concept of God is stupid, some are tautological, and
           | some are experiential. Eg the concept of God is love (if you
           | have faith in the concept and reality of love being real).
        
         | nurettin wrote:
         | It would probably slow down or cause elevated heat between two
         | mirrors.
        
         | WithinReason wrote:
         | It would be exactly like this one
        
       | disillusioned wrote:
       | Only tangentially related, but the lovely (quite) short story "I
       | don't know, Timmy, being God is a big responsibility" is
       | fantastic and kind of hits on simulating worlds, in a sense:
       | 
       | https://qntm.org/responsibility
        
         | golergka wrote:
         | I just love how a world-class quantum computer scientist who
         | just made a discovery that just blows up everything known to
         | mankind is up to the very end is worried about missing a bus.
        
         | gavmor wrote:
         | To deepen this tangent, I'll recommend Philip K. Dick's _The
         | Trouble With Bubbles_ which imagines 60s cocktail party guests
         | showing off their miniature planet-scale terrariums.
        
           | arminiusreturns wrote:
           | Amazing, thank you for introducing me to this!
        
         | Waterluvian wrote:
         | I'm not sure I really know how to handle this. Do I just read
         | the latest version linked at the top of the page? Or is the one
         | offered by this like somehow more canonical or something? I'm
         | not sure I've ever been faced with different versions of a
         | fiction before. Just textbooks.
         | 
         | I really love thought pieces like this if you refrain from
         | poking holes in the logic or physics. I love the idea of a
         | multiverse where they're all actually just identical so it's
         | mostly moot.
        
           | bee_rider wrote:
           | Canon is just a construct invented to sell merchandise and
           | keep out competitors. Enjoy whichever version of the story
           | you'd like!
        
             | Bluestein wrote:
             | Enjoy all. Several, in fact :)
        
           | scbrg wrote:
           | > I'm not sure I've ever been faced with different versions
           | of a fiction before.
           | 
           | You probably have, but haven't thought of it like that. Ever
           | seen a _Director 's Cut_ version of a movie? :-)
        
             | Waterluvian wrote:
             | Oh gosh it's true. And that whole Star Wars thing.
             | 
             | I guess I've just not yet faced it with print.
        
               | LoganDark wrote:
               | > I guess I've just not yet faced it with print.
               | 
               | Sure you have, if you've ever bought an Nth edition of a
               | book (where N > 1). Editions aren't always just an
               | artwork/formatting change, they sometimes contain changes
               | to the text too.
        
           | Andrews54757 wrote:
           | I read both. They are both great but I like the original
           | better. The new edition is accessible but I think the
           | original's prose is beautiful.
        
         | diego_sandoval wrote:
         | I'd love to read alternate endings to it.
         | 
         | I've been thinking about writing a story with a very similar
         | plot for a couple of years, but it had a big plot hole:
         | computation overhead between the universes, and I hadn't
         | thought about quantum computers as a way to solve it.
         | 
         | The other main difference with the story that I had in mind is
         | that the characters would write a story about it, which would
         | be "my" story, and they'd find a way to make it so that the
         | ending would tell the reader the universe depth they are in, by
         | creating a variable whose value is incremented by 1 for each
         | universe.
         | 
         | For anyone reading this on HN, you're 8474771628371839 levels
         | deep.
        
           | JumpCrisscross wrote:
           | > _it had a big plot hole: computation overhead between the
           | universes_
           | 
           | Unless you're going hard sci-fi, you can do what this story
           | did. Give them by fiat "infinite processing power and
           | infinite storage capacity."
        
             | LoganDark wrote:
             | I think all of qntm's stories are hard sci-fi.
        
               | Retric wrote:
               | Infinite processing power, infinite storage, zero
               | latency, etc is about as soft of a setting as it gets.
        
               | LoganDark wrote:
               | Is it? A new fundamental particle doesn't necessarily
               | make it soft sci-fi. The story seems perfectly technical
               | to me.
               | 
               | Can't black holes already encode an infinite amount of
               | information past the event horizon?
        
               | Retric wrote:
               | > Can't black holes already encode an infinite amount of
               | information past the event horizon?
               | 
               | No, current physics has a bunch of hard limits on
               | information.
               | 
               | > A new fundamental particle doesn't necessarily make it
               | soft sci-fi
               | 
               | Calling something a particle doesn't matter here. It's a
               | fully formed computational device that happens to
               | magically solve all problems.
               | 
               | Consider, how do you encode and read information from
               | such a particle. Qubit's are physical properties of
               | something, such as spin. Is this particle supposed to
               | have infinite properties which you can access with
               | infinite precision? No, it's just a magic macguffin that
               | does whatever the author wants.
        
               | rcxdude wrote:
               | They're pretty soft, I would say. Most of Fine Structure
               | is basically just magic.
        
               | LoganDark wrote:
               | If you're going to accuse something of using magic, I'm
               | surprised you didn't accuse Ra, which even has something
               | called 'magic'. I've been reading Fine Structure this
               | morning and it doesn't seem magical to me at all. It's
               | about as magical as quantum physics would be, I guess.
               | 
               | I suppose even Ra still obeys the speed of light, though.
        
           | LoganDark wrote:
           | > For anyone reading this on HN, you're 8474771628371839
           | levels deep.
           | 
           | "Do you know how big the average positive integer is?"
        
           | Bluestein wrote:
           | > 8474771628371839
           | 
           | 888 412 1289018?
        
             | LoganDark wrote:
             | > 888 412 1289018
             | 
             | 0118 999 881 999 119 7253?
        
               | Bluestein wrote:
               | > 0118 999 881 999 119 7253?
               | 
               | ... 262144 4782969 100000000 2357947691 61917364224
               | 1792160394037 56693912375296 1946195068359375 :)
        
         | zxexz wrote:
         | I remember watching a (wonderful) T.V. show[0] that came out
         | within the last couple decades, and feeling like a certain
         | scene was definitely a nod to this story. The drama, and
         | physics (and resolution) was done differently, but it left me
         | in a similarly, pleasantly pensive state. [0] I almost made the
         | mistake of naming it, or the director - but caught myself,
         | realizing the context of this comment alone could be a major
         | "spoiler".
         | 
         | Maybe I've encoded the name in this comment (honestly though, I
         | tried, and it's late - maybe search engines are good enough for
         | it these days :) )
        
           | kennyadam wrote:
           | What's the name of the show?
        
             | zxexz wrote:
             | U+200E before letters spelling out show in my comment. Just
             | noting that while I would have enjoyed the show very much
             | even if I had this "spoiler", it certainly would have lost
             | some "magic".
        
               | chii wrote:
               | you could use a url shortener to hide the link to the
               | show's wikipedia page. For those who don't mind spoilers,
               | they can know what you're talking about.
        
               | arrowsmith wrote:
               | https://tinyurl.com/mrx6rfef
        
               | fredoliveira wrote:
               | That is, in fact, a great tv show.
        
           | namanyayg wrote:
           | I think they definitely got "inspired" from qntm's story, but
           | the ending of that TV show was unwatchably bad.
        
         | mbil wrote:
         | Thanks! For anyone who liked that here's another [0] short
         | story in the same vein.
         | 
         | [0]: https://pastebin.com/raw/gA4aRc0T
        
       | niccl wrote:
       | does anybody know what the music accompanying the full video was?
       | It seemed familiar but I couldn't place it. Maybe AI generated?
        
         | pietervdvn wrote:
         | It sounds an awful lot like "Maiden Voyage" (the instrumental
         | version) by the clockwork dolls, but not quite.
        
         | FrancoisBosun wrote:
         | Sunshine (Adagio in D minor)
         | 
         | https://open.spotify.com/intl-fr/track/50ExtKr8j9cHTY3OEw282...
         | 
         | I asked Siri to identify the song.
        
           | dheera wrote:
           | Sounds more like "jackhammer in D minor" rather than an
           | "adagio"
        
       | FredPret wrote:
       | Today, a simple simulation at 60fps.
       | 
       | Tomorrow: "When you gaze long into the simulation, the simulation
       | gazes back"
        
       | swayvil wrote:
       | >written entirely in GLSL fragment shaders
       | 
       | What's the language for that?
       | 
       | (The music is pretty cliche. Maybe it was written by AI)
        
         | daemonologist wrote:
         | The music is "Adagio in D Minor", and probably cliche more
         | because it's been used so much rather than because it was
         | cliche when written. It was originally composed by John Murphy
         | for the 2007 film _Sunshine_.
         | 
         | https://en.wikipedia.org/wiki/Sunshine:_Music_from_the_Motio...
        
           | snitch182 wrote:
           | Sunshine is one really fine piece of film. Beautiful.
        
         | ascar wrote:
         | Not sure if that's actually your question, but GLSL is the
         | language
         | https://en.m.wikipedia.org/wiki/OpenGL_Shading_Language
        
         | niederman wrote:
         | GLSL is the language.
        
       | ahmadmk wrote:
       | There is an excellent hard science fiction book called
       | permutation city that very related to this topic...it made me
       | feel like i was in a dream when i read this post's title
        
         | redbluething wrote:
         | I finished that book yesterday. I had exactly the same
         | reaction.
        
         | netcraft wrote:
         | I havent yet read permutation city but Diaspora is one of my
         | favorite sci-fi novels. I need to make time for it
        
           | xwolfi wrote:
           | Diaspora gives me shivers just thinking about it. Permutation
           | City is fun, but not as inspiring as Diaspora.
        
             | Bluestein wrote:
             | He - rightly, and often - makes these rounds here when
             | simulacrums are at hand. Well deserved.-
        
           | exe34 wrote:
           | there's a short story in his anthology that is a sequel to
           | diaspora. oceanic.
        
             | netcraft wrote:
             | I had no idea it was related to diaspora. After reading
             | only the first few paragraphs I can't wait to read it all.
             | Thank you!
        
               | exe34 wrote:
               | tbh a number of the other short stories could be
               | considered prequels to diaspora.
        
         | catoc wrote:
         | Permutation City is briljant - Greg Egan has many (free)
         | stories exploring physics on his website:
         | https://www.gregegan.net/
        
           | BelleOfTheBall wrote:
           | Egan is one of those rare writers where reading his book made
           | me realize just how much smarter he is than me. Not even in a
           | negative way, it's simply like listening to a lecture by a
           | brilliant, brilliant man.
        
       | o11c wrote:
       | Not sure why, but all the shadertoy examples embedded in the page
       | play at like 0.6 FPS for me. When I open the linked "final
       | shader" on the shadertoy website I get 60fps just fine ...
        
         | CGamesPlay wrote:
         | If your browser is like mine, there is a clipped play button
         | below the rewind button that resolves the issue.
        
           | o11c wrote:
           | Ah, that indeed works.
           | 
           | Taking a look, the CSS throws warnings about being ignored;
           | adding "position: absolute" fixes that and makes the button
           | fully visible.
        
       | reason-mr wrote:
       | In truth, it must be said that some details were omitted by the
       | simulation :)
        
       | kmoser wrote:
       | Back in 1996/1997 I worked on a CD-ROM game that simulated
       | movement of the tectonic plates, as well as temperature,
       | elevation, and precipitation, over millions of years. Amazing to
       | see how evolution (heh!) of computing hardware and software have
       | come so far in 28 years: https://www.kmoser.com/evolution/
        
         | fersaysrelax wrote:
         | I think you are the first person I come across that knows that
         | game and you were an actual dev on it! So thank you! I played
         | it when I was around 13(I think) and I loved it. The whole
         | concept of simulating a planet and the animals on it was pretty
         | much mind blowing for me at the time(it still is). I should
         | have kept the poster that came with it...the different sapien
         | evolutionary branches were really interesting.
        
           | kmoser wrote:
           | Cool! It's admittedly an obscure game. My main contribution
           | included the random generation and movement of the cratons.
           | This involved mapping Cartesian to spherical coordinates but
           | harder because each row of tiles was offset by half a tile's
           | width from the rows above and below, like a brick wall.
           | 
           | We wrote an in-house editor that let us create and animate
           | the different cratons, starting with the Pangaea
           | configuration (basically all cratons stuck together as a
           | giant continent) all the way through to how they are arranged
           | now, to simulate how they moved historically. That was also
           | difficult!
           | 
           | I also worked on the initial placement of some visual
           | elements that dotted the landscape, and the serialization of
           | the different data structures for loading/saving games.
           | 
           | After it shipped they gave each of us devs a couple of
           | shrink-wrapped copies of the boxed final product but weirdly
           | they were not the US version. I still have an (unopened)
           | Portuguese version that probably has the poster.
        
       | harha wrote:
       | One of my favorite courses at university was energy policy
       | analysis, where we played around with the EPPA model (developed
       | at MIT) [0]. We made changes to certain parameters to see how
       | things might work out, e.g. if cost of energy storage is reduced
       | 10x.
       | 
       | Lots of fun, but I unfortunately never managed to find anything
       | similar to do in my job.
       | 
       | [0]: https://globalchange.mit.edu/research/research-tools/eppa
        
       | GardenLetter27 wrote:
       | Why only fragment shaders? If you had vertex shaders for a
       | heightmap too then you could zoom down to the surface.
        
       | noduerme wrote:
       | Mm..cool but the last part where any civilization that has night
       | lights would by definition burn all the fossil fuels and turn the
       | place into a desert seems like an assumption based on only one
       | possible trajectory of our own civilization, let alone all other
       | possible alien civilizations. There's nothing to make death by
       | warming and desertification any likelier than nuclear war or the
       | development of clean fusion, or a plague or an invasion from
       | another nearby procedurally generated earth-like planet.
       | 
       | Basically it's a cool sim when it's trying to simulate stuff that
       | actually happened, and before it gets opinionated.
       | 
       | Moreover, it apparently equates heat with dryness, and also
       | doesn't take into account the effect of additional CO2 on plant
       | life. It _is_ called a greenhouse effect for a reason. It 's
       | quite possible the equatorial belt could heat up to where it's
       | uninhabitable by humans but overrun by jungle rather than desert.
        
         | baxtr wrote:
         | While I have some doubts some of your statements your comment
         | still resonates.
         | 
         | Unfortunately, we live in an "Excel world". The predominant
         | thinking is that our highly complex world can be modeled into
         | an excel sheet. And based on the outputs we should make
         | decisions.
         | 
         | This approach _mostly_ ignores the second order effects you
         | describe.
        
           | idunnoman1222 wrote:
           | Climate change predicts a warmer wetter world The author just
           | didn't know this
        
             | Qem wrote:
             | The issue is, the locations where most humans live today,
             | grew historically from the best spots our ancestors could
             | find in the whole planet, taking many factors in
             | consideration: proximity to water bodies, good climate,
             | good agricultural lands, adequate rainfall, et cetera.
             | These are not random locations, they grew around the best
             | spots available. If climate changes, they tend to regress
             | toward the mean, diminishing carrying capacity. Other
             | places may even improve, from the POV of human
             | habitability, but statistically those will not be the same
             | we have a lot of people living today, but places like
             | siberia, that historically were population voids, prompting
             | the need for mass migration and mass resettlement in a
             | world that is already full of borders, and all the
             | associated problems this entails.
        
       | paulddraper wrote:
       | Worlds within worlds
        
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       (page generated 2024-07-30 23:02 UTC)