Ringworlds

[@theCodyReeder]

The problem I had with it is it wouldn't have gotten dark immediately but rather gradually over at least an hour or so just like how the moon blocks the sun during an eclipse even if the edges of the squares where sharp.

[@thermophile2106]

Cody'sLab It would depend tho. The outer ring would be moving so much faster than the light ring, that the partial eclipse would only last a short time. I think a better solution would be to just make the edges uneven, kind of like a bunch of long triangles. That way you could use the same amount of matter, but prolong the partial eclipse.

[@isaacarthurSFIA]

Yes, and it does kind of depend on how close or far the light squares are from the ring and sun, I actually can't recall if Niven had those squares in a natural 24 hour orbit if the sun or one which just had a given square gaining ground on the ring ate a rate of a square's width every half day. It won't be an instant transition to dark either way, since the sun has notable diameter and angular width but I think in both cases it is going to be quicker and more abrupt than we're used to, even if one should be a lot more gradual.

[@louisbluemeanie3]

Love your vids man

[@mkd2839]

Cody'sLab Not to mention that the atmoshpere is going to scatter the light, prolonging the transition

[@amazingbigd246]

Go cody go cody

[@CommanderM117]

“Halo! Its divine wind will rush through the stars, propelling all who are worthy upon the path to salvation.” - Prophet of Mercy

[@mrnohax5436]

*SALVATION FOR ALL*

[@GeckoInept]

When you first saw Halo, were you blinded by its majesty? Paralyzed? Dumbstruck?

[@skylertremblay3395]

LET THE GREAT JOURNEY BEGIN

[@unihabitedwhip4626]

@@GeckoInept NO

[@skylertremblay3395]

@Jose Lopez the weight of your heresy will stay your feet.. and you will be left behind

[@jetflaque8187]

One Ring, to rule them all, One Ring to find them, One Ring to bring them all And in the Darkness (of space) Bind them.

[@kineticdeath]

and then they make 6 more and sterilise the galaxy with them!

[@ignaspetrauskas8763]

Didn't expect that, but ok

[@Joshua_N-A]

@@kineticdeath Halo arrays

[@como_que_no5]

Sing It at the tune of Halo theme.

[@saoirsetoohey8692]

In the Silmarillion, Tolkien considered Middle Earth itself to be 'Morgoth's ring,' due to how much of his malice and evil will he poured into it. It also used to be flat. Ring world Middle Earth confirmed?

[@Juay_deRito]

"When you saw Halo, were you too blinded by it's majesty?"

[@titanium_rocket1505]

"Blinded?"

[@mrnohax5436]

Titanium Labs paralysed... dumbstruck

[@titanium_rocket1505]

@mr Nohax No

[@alecmize7154]

@@titanium_rocket1505 Yet the humans were able to evade your ships, land on the Sacred Ring, and desecrate it with their filthy footsteps!

[@titanium_rocket1505]

@@alecmize7154 Noble hierarchs, surely you will understand that once the parasite attacked…

[@JohanDanielsson8802]

In Stellaris, a ring world only equals four big planets. Seem like they are a little off mark there.

[@manictiger]

To be fair, it also assumes people make it, instead of the much more practical Von Neumann machines (exponentially self-replicating bots, which could do anything from build, transport resources, or fuse together to become parts of the ring).

[@toninhosoldierhelmet4033]

@@manictiger the grey tempest is kind of a problem but i wish nanites were a piece of researchable tech capable of speeding up the building of megastructures, living metal does that instead.

[@nathanjora7627]

Johan Danielsson well not really. Or rather, not more than in any other respect (number of stars, of habitable planets, pop capacity per system, etc). It’s a game after all, you don’t want to break it by allowing the player, or worst : an ai, to have a million planet pop capacity in just one system alone. Take it, protect it, build your pop in it, and you could literally just have this one system and still have enough firepower to level the rest of the (stellaris) galaxy. (Of course, you probably knew all of that already ^^)

[@martijnvanweele6204]

It is a known fact that sci-fi writers have no sense of scale...

[@manictiger]

​@Wischmopps Uh, yeah it does. It entirely matters whether it's organic or nanite labor. Nanites would be the go-to method in the future. Just as weevils can turn your rice into more weevils, nanites could turn asteroids and planets into more nanites, then fuse together to make the ring world. It would take eons for organic labor to do what nanites could do in a couple years.

[@micha-elcleveland1265]

Larry Niven is a premier hard science fiction author. Clearly in my top 10

[@micha-elcleveland1265]

When we gain the ability to control gravity, many of the problems resolve. To learn the 3-6-9 of electromagnetism is the probable key.

[@Tuttomenui]

Ring World, more sex than game of thrones. =). Do you rishathra?

[@mykobe981]

Micha-el Cleveland- Tesla. ;-)

[@faroncobb6040]

Gravity control (AKA magic) doesn't really help much. You would still have to come up with an energy source capable of supplying energy equivalent to 1g of continuous acceleration for all the matter that was being affected by your artificial gravity, an amount that would likely be a couple zeros more than the mass of the Earth. A ringworld may not be 100% impossible, but it is 100% impractical, which is basically the same thing.

[@MartyParty23]

Excellent taste, but honestly I enjoyed the sequels more than the original. It was the book that got me into sci fi and put me on the path to becoming a writer.

[@lazarus2691]

If my math is right, it would take you approximately 25,000 years of non-stop walking to go all the way around a 1 au ring world, or about a century in a jet airliner. That's mind boggling.

[@Rando_Shyte]

I would think it would be far longer no?

[@lazarus2691]

A 1 AU radius ring is 939,474,630 km in circumference. The average walking pace is about 5km/h Which means 188 million hours. There are 8766 hours in a year. 188 million over 8766 gives 21,447 years. An airliner is approximately 200 times faster than a walking person, so divide 21,447 by 200, gets you about 106 years

[@theutopianoutopioan464]

Brent Smith , By the time a civilization can build a ring world , they'll have much faster transportation for getting around the ringworld than jet planes !

[@lazarus2691]

The Utopiano Utopioan And your point is? I was just using a comparison with modern speeds. I never said anything about them actually using it.

[@SergeyPRKL]

The Utopiano Utopioan it would be pointless to travel on surface. easiest would just be to hop off the ring inwards towards sun, an ballistic arc then aim at your destination or stay still in your location and wait until your travel destination on ring goes by and land back on the surface. Also when it rotates sun in 9 days, longest distance is 4,5 days. Even shorter distances, let's say 10% of rotation, would be easier to travel like this. Just wait 90% of the ring pass by in 8 days. This, ofc needs to be done in 1200km/s.

[@ParameterGrenze]

I read the Ringworld series a dozen of times. Love it.

[@klausgartenstiel4586]

ringworld is one of these science fantasy concepts where you have a certain idea of what a thing has to look like and then you try to bend the laws of physics around it so that it fits.

[@isaacarthurSFIA]

True enough :)

[@JK03011997]

Jup, to achieve a ring world you need some serious magic tech.. and by that point why bother building it? With the resources you could pretty much go full on type 2 anyway. And as I calculated on reddit a passive material for one would need to float on water yet still be able to contain a moderate hydrogen bomb. And that is the smallest of the issues, you also need 75000 earths worth of air, and the mill down the equivalent of earths mass to dust, just to have enough soil. And that is for a pretty small ring, certainly smaller than the one isaac showed in the video

[@IamGrimalkin]

Jonas Kr. In the ringworld book the ringworld was seen as astonishing by a civilisation who already had several Dyson spheres.

[@IamGrimalkin]

Michael Bishop I think in ringworld I remember the two-headed guy saying that making inhabitable Dyson shells was relatively easy, you just add artificial gravity generators to hold the air in. (The problem is making *safe* Dyson shells: if one artificial gravity generator breaks, all your air will be sucked out.) The astonishing things about the ringworld were: -They were using spin gravity, not artificial gravity. -The ringworld ring blocks exactly 76% (?) of neutrinos.

[@klausgartenstiel4586]

so i guess i won't see one of these in my lifetime... but who knows? aks me again on my 200th birthday.

[@DigGil3]

Overwatch must be happening in a ringworld: It's always high noon.

[@robinchesterfield42]

Or their planet is tidally locked. :)

[@innsj6369]

Or they have an artificial sun in geostationary orbit!

[@MrFuller876]

@James Braselton Jesus Christ I never seen such bad grammar in my life. Not to be rude though.

[@patronofsaints2062]

@@robinchesterfield42 a tidally locked planet is almost always extremely hot

[@cosmic_gate476]

@James Braselton thank you for the prophecy, idk why people focused more on the grammar when it was obvious

[@mega-bustershepard5537]

It would make a hell of a setting for a fantasy novel. All the different aliens would make excellent fantasy equivalents.

[@RobotB-hd5hs]

Yea, maybe because of the distances are so great that a common ancestor diversified.

[@mega-bustershepard5537]

Like Neanderthal man. Or possibly other races could "crash land" on the ring, their distress signals dampened by the machines that run said ring. (Possibly by being shot down by the meteor defense lasers). Plenty of excuses for a grand Burroughs-esque adventure.

[@JonathanX95xboxlive]

Have you ever played Halo?

[@mega-bustershepard5537]

I own copies of every Halo game released so yes.

[@jre-1337]

..... It's been a setting since Larry Niven released Ringworld. In like the 80's.

[@icedthai]

The conspiracy theorist would argue they live on a spherical world.

[@iminformedbecauseisawabunc9402]

lel

[@ireneuszpyc6684]

not only conspiracy theorists: there would also be religious freaks claiming that their holy scriptures declare that they live on a spherical world

[@barahng]

Eryk Pyc *tips fedora*

[@travistrue2008]

But only a *legit* conspiracy theorist would argue that we live on a spherical ring world.

[@farmingtonfakenamington3048]

He would argue they lived on a arch not a ball.

[@tonystark001]

Every time I watch these video's I end up firing up stellaris

[@NeostormXLMAX]

Its been years and i still get this feeling when i reqs sci fi

[@Breakfast_and_Bullets]

No mention of Halo? I'm surprised. Great video, as always!

[@ABitOfTheUniverse]

I am surprised too, given video games are like modern day graphic novels. Isaac may want to research these scifi ideas uses in video games, and use some references from them, to make his videos more appealing to wider audiences.

[@smorrow]

Halo is a Banks orbital.

[@sidgar1]

Halo orbits a gas giant and not a star directly IIRC

[@Breakfast_and_Bullets]

Yes, Halo is a Banks Orbital, which is why I'm surprised it wasn't mentioned when the topic came up

[@JK03011997]

@Parker Brown culture style orbitals were mentioned very briefly. However they suffer from similar issues, the maximum radius a ring spinning to give 1g made from kevlar can have is ~680km, about half the size of pluto or around 50% of the length of GB or 15% the distance from NY to LA (pick an option depending on your continent I guess). So to give it the crop land area of earth it'd need to be ~16000km wide, essentially making it just a simple rotating habitat. (check out my comment on the reddit for the maths) www.reddit.com/r/IsaacArthur/comments/703g28/megastructures_ringworlds/

[@PhysicsPolice]

In the philosophy of science the word "real" applies to both emergent and fundamental things. I don't get why people are so hung up on the emergent nature of inertial forces.

[@hamentaschen]

Thank you Mr. Arthur for all of your hard work. I cannot tell you how much I love your videos. HAPPY ARTHURSDAY!!!

[@ABQSentinel]

If you really enjoy his videos, consider becoming a Patreon supporter (if you're not already).

[@TheOneWithComments]

Before I watch this I just want to say that I've been waiting for this video since your first megastructures video so thank you for revisiting this topic, and I am excited for the discussion after.

[@JK03011997]

Try joining us on the reddit for the discussion, the structure is a lot more organised over there www.reddit.com/r/IsaacArthur/comments/703g28/megastructures_ringworlds/

[@passthebutterrobot2600]

Thanks, ringwords are such an awesome concept even if rung-worlds or smaller rings appear to make more sense engineering-wise. Re civilization collapse: If I were building a ringworld I'd definitely want to bury plenty of raw materials & fossil fuels about the place just in case. Without them surviving stone-age or medieval inhabitants might find returning to high-tech levels a bit tricky.

[@jengleheimerschmitt7941]

Good call. I say max out on solar panels for a while and start manufacturing synthetic oil and coal. Store it inside the mountains. Some high-density plastic and stainless steel mines... I'd want to keep them spread out and difficult to access so people have to work for it. You'd want to set it up like an Industrial Revolution video game set to Easy. "Congratulations! You have invented the steam boat. You may proceed to the Island of Copper.

[@grassyclimer6853]

So this is what royalty in the future will propose with?

[@420StonerComedy]

Naw, Marvel's Celestials.

[@grassyclimer6853]

420StonerComedy earth is the wedding cake

[@JohanDanielsson8802]

That would make the ring millions times bigger than the cake! :D

[@platinumcoolest]

The cake is a lie.

[@timothymclean]

Royalty rich and powerful enough that they can disassemble entire solar systems as a romantic footnote would be impressive indeed. It implies an economy massive enough to treat entire solar systems as we would households, or even individuals, and that much of it was controlled by a single royal family. So...K3 monarchy, bare minimum.

[@AndyTrampke]

Isaac I just want you to know your content is helping me beyond what you could anticipate. My father passed away recently and watching your videos helps me to keep looking up and think beyond my own existence. You keeping me thinking and dreaming of what may be in the future is helping me cope immensely. Thank you!

[@isaacarthurSFIA]

My condolences Andy, I'm glad the episodes are helping.

[@TheMasonX23]

Spent the morning rewatching the other megastructures videos in anticipation. Happy Arthursday everybody! :)

[@hatamorey1]

Would u rather: Humanity being the only civilization in the Milky Way Galaxy so we can become Type 3 ? Or have other Civilizations scattered around the Galaxy?

[@jamesfra1311]

hatamorey Wonder what memes aliens have..

[@marcopolo3001]

Maybe they don't have memes and go to work like a busy worker bee -_- what if we are the only civilization in the universe to have bothered with memes...oh my head wants to explode now.

[@hatamorey1]

james Fra hopefully they arent that advanced...humanity should be worshipped by primitive aliens

[@Youkalottaseeya]

The former obviously. If other civilizations occupied the galaxy let alone the universe there'd be competition for resources and living space if we ever reach high end intragalactic means of travel.

[@TS-jm7jm]

hatamorey the former, the imperium of Man must come to pass

[@hubbaba]

You must have had fun saying "For that matter..." when talking about how the structure of matter.

[@TheGreatPurpleFerret]

Hey its Arthursday! Pack your bags kids, we're going to SPACE!

[@LetsgoPats56]

NedryOS seatbelts everyone

[@williammook8041]

I thought when I read Ringworld the first time in the 1970s that instead of sun squares you could have fresnel lenses like my friend Bob Forward proposed for directing solar pumped lasers when driving laser light sails across interstellar distances. These lense bunch up light on to half the area along a cosine curve for each 24 hour section. This lets you double your radius and living area as you say. So glad to see you mention it. You can also build the ring wider than Niven's ringworld by curving the ring along the rotational axis - which helps with your seasonal variation across the width as well and maintain net force perpendicular to the ring surface even as total value changes. Since the value of g changes between pole and equator on Earth a similar variation across the surface of the ring in a direction perpendicular to the spin plane isn't a huge problem compared to the problem of building the ringworld in the first place. One material I thought might be possible is the production of stable negative leptons 2000 times more massive than a proton would put positive and neutral baryons on the outer shell the size of a nucleus and put the negative leptons on the interior. Tauons are supermassive negative leptons that are heavier than protons. These have very short life spans. However even heavier leptons are possible. While their life times become shorter, their interaction times and lengths become shorter not as quickly. This means just as Cooper pairs of ordinary leptons (electrons) can create stable superconduction, it it very likely that at around 2000 times the mass of the proton pairs of leptons can exchange energy in ways that make them stable long-term. Stable negative leptons at this mass produce inverted baryonic matter that is millions of times stronger than leptonic matter and trillions of times denser than leptonic matter. Inverted matter coated onto aerogels making material of ordinary density and extremely stiff. Bulk inverted matter is useful for gravity machinery. Start building the ringworld by depositing self replicating utility fog on to the surface of the Sun or host star. A single square meter enters an orbit just above the photosphere travelling 7.9 km/sec less than orbital velocity. Produces 1 g in the solar panel. The panel reflects away all light and radiates away heat in the shadow of the panel. It uses a portion of its energy to fly in the plasma of the photosphere using magnetic wings. Magnetic forces select and cool metals from the photosphere which are used to grow the 1 square meter ring. Surplus energy is used to make dense positronium which stores energy. Added metals are also accumulated and both are assembled into a sun circling mass driver that ejects positronium and metals including completed parts out of the photosphere to 1.988 AU radius. There photonic thrusters circularise the orbit. In this way the light ring is first built. 34.77 MJ is required to project 1 kg in this way. So, 11.07 quadrillion tonnes per second may be projected from the Solar surface. Or up to 4.2 million tonnes per second of positronium may be projected from the solar surface. With a 1 hour replication time it takes 62.4 hours to cover the sun. At that point 4.2 million tonnes of positronium may be ejected from sun, or up to 11.07 quadrillion tonnes per second may be projected from the solar surface. It takes 96 years to extract all of the metals from the sun. Each year 102 metric tons per square meter is added or 78.91 milligrams of inverted matter may be added. The atmosphere is 10.8 tonnes per square meter, and soil and water is 89.2 tonnes. With 2 tonnes of structure - which has 78.91 milligrams of inverted matter forming femto-tube network to give it strength. One approach is to use the inverted matter to make self-replicating zero point machines that extract more inverted matter from the zero point in an exponentially growing material. Growing from 78.91 milligrams to say 200 kg requires 21.27 replications in a zero point amplifier of some sort. Capture sunlight and use it to drive a 1.988 AU radius particle accelerator the same radius near the outside, powered by the unused portion of the Sun's light would be quite capable of making lots of exotic matter. Ultimately with high efficiency processes 4.2 million tonnes per second may be produced from the solar energy. Of course 10.8 billion tonnes per second of inverted matter may be produced if the zero point amplifier works as describes. Inverted matter is very strong and resists punctures and wear. In fact, you could have a wide range of technologies available that make use of this material's unusual properties. One is transforming hydrogen to heavier isotopes with something as simple as a piston. Another is an efficient radiation shield. While not as strong or as dense as black hole dusts that are drawn from the zero point - it is a technology that is transitional from our chemistry and physics to more advanced tech - and one that makes ring worlds easy. A 4 AU diameter ring completes one orbit every 1033 days so each 12 hour day is 910,000 km bright strip and 910,000 km dark strip. A fixed set of cylindrical lenses forming 1033 bright spots whose illumination level follows a cosine curve to mimic the daily cycle of a spinning planet, naturally produces the required variation in light. An active holographic optical element (HOE) 1,820,000 km long operating 1,820,000 km interior to the ring across a 1,820,000 km wide strip focuses light across the entire length of the strip into the bright region around the ring which is fixed in space relative to the center of the sun. A 455,000 km length of strip is in darkness, and then a 910,000 km long strip is in light which rises according to the cosine function for 455,000 km and then falls from the peak another 455,000 km and then darkness for 455,000 km. So, 30 degrees from light arriving at the HOE at midnight directed toward dawn. So, with a fixed array of spots like this the ring world goes through 1033 days and nights. Length of days can vary and for a HOE strip that is wider than the ringworld seasonal variation can be introduced as well. 1033 days is 2.82 annual cycles of this type. Of course unused light is available for powering equipment industry and transport on the ring world. Now with a radius of 2 AU minus 1.82 million km we have a HOE radius of 1.988 AU which has an orbital period of 1023.8 days. A 10 day difference over 1033 days. Reducing day night interval 23.78 hours. Now adjusting the length a little reduces the number of day and increases length to 24 hours again. Another approach is to have an active hologram that redirect light in a controlled way so that the optical pattern remains stationary even as the optical elements themselves move.

[@myusername5]

Ringworld’s most important benefit: rishathra.

[@d.thieud.1056]

i didnt know what rishathra meant but i saw isaac likeed it... now i wish i had never googled it...

[@Solon1581]

en.wikipedia.org/wiki/Rishathra

[@Thehairysoap]

why rishathra when the space unicorn gives you tasp.

[@d.thieud.1056]

lets just say google didnt put the wikipedia result 1st, rather "search images of "rishathra", with examples...

[@iona2225]

I saw this on Babylon 5 once, or at least an attempt at it XD

[@thetayz72]

Imagine the fun we could have with time zone coordination on this bad boi

[@chrisklinetob7389]

I was initially tempted to tease the narrator's difficulty pronoucing certain letters. This narrator / author is clearly a genius deserving respect & praise for making these AMAZING videos.

[@dantess2693]

This video stretches the imagination in all the right ways. Love it, and love the concept!

[@ephennell4ever]

Dantess26 ... If you loved this video, you *will* love the Ringworld series of books!

[@heliomoonwave]

Ringworld is one of (if not the) all-time best sci fi novels, hands down. The person who did those graphics of the ringworld absolutely nailed it! Perhaps someday humanity will achieve such a structure.

[@mheermance]

Ringworld is a great book and I highly recommend reading it to anyone who hasn't. It's good to hear that building one is possible, although extremely difficult.

[@g3user1usa]

I've reread some of the Ringworld sci-fi series a few times because they were so exciting to me. Ringworlds, to me, are absolutely the coolest structures in space. I keep thinking of how the Ringworld was 600 million miles in circumference. Inhabitants would almost never run out of land to explore. I wonder how long it took for Ringworld engineers to build Ringworld. Tens of thousands of years? I'd always hoped there would be a movie or two about Ringworld.

[@SarabandeGreens]

Ahh this will be the perfect boost to get me through the end of my work day. Though currently working on finishing building out a kitchen isn't the best noise wise, I have good taste in headphones thankfully. Also love the books!!! Might actually pick up the audio since its been so long.

[@oldered5663]

We don't have to wait for 2 weeks for an "Uplifting episode" because every episode you make is UPLIFTING :)

[@thewalkingtaco9736]

You give me so many new things to study with each video. Thank you.

[@michael3263]

Fafnir Agreed! Mr. Arthur is virtually singular in that respect. You don't get this level and quality of information from anyone else on KZbin that I've ever found.

[@hakusansaku8800]

This is the way of how to make "calculations in physics" interesting nowadays. Who needs homework if you can check arthurs statements with your own calculations on 20 pages of paper.

[@chrisgarcia6098]

I have no power at my house cause of Irma, but that doesn't matter cause I have phone data and its Arthursday!

[@iainnoonan4337]

Oh finally I can relax and watch these great video, my contract is over in the UK!!! and I'm sitting in a hotel room waiting to take a flight to America.

[@isaacarthurSFIA]

Safe flight! I hate those transoceanic ones.

[@iainnoonan4337]

Thanks Isaac

[@seraphina985]

+Isaac Arthur Ugh yeah reminds me of the 10 hour flight I had to take from Amsterdam to Atlanta by the time the plane got to Newfoundland I was already like "I really don't want to be on this damn plane anymore". Unfortunately Georgia is still a damn long way from there especially when you are spending the whole time unable to fall asleep no matter how hard you try and spending the whole time just wishing the thing would hurry up and land so you can get off and take a nice walk.

[@HorzaPanda]

My fiancé lives in Florida so I entirely get you on that. I am terrible at sleeping on planes so the way back is always worst

[@jengleheimerschmitt7941]

Any chance you're in the Neutronium wholesale business?

[@kennethquinnies6023]

I think one reason we may not have been able to detect ringworlds or dyson spheres is that the more advanced civs may have figured out zero point energy, thus no need for massive solar energy capture systems.

[@kirumy-toz]

Ahhh, I thought I was missing something before bed. Thank you, Arthur for providing me my end of day stress relief.

[@TS-jm7jm]

just got to SA on a trip and isaac shows up on my feed made this whole horrible day worth it.

[@7lllll]

20:26 i do not think we should hide weird horizons. natural looking environments are certainly good for our health, but i don't think that includes removing unnatural horizons that are just as aesthetically pleasant as earth's

[@brookestephen]

I've built the ring in Virtual Reality, and the nearby part of the ring looks flat, while the distant parts of the ring appear like an Arch that passes behind or above the central star.

[@alanfriesen9837]

You know where one of these might be worth doing first? A system with a small star and no habitable planets. What would you think of Barnard's Star?

[@lord_hemp]

You'd need enough material to build it, and barnard's star is flying through space at a good speed, so it may or may not have enough material to build a megastructure

[@lloydhembury925]

Just finished up halo master chief edition. Curiosity brought me here, and the science kept me here

[@SocksWithSandals]

What a fascinating, fast-paced and beautifully presented nuts and bolts vision of future technologies. And you pump out one of these a week?!

[@cizcalodiablopanzon]

You are the only reason KZbin is worth watching! Isaac Arthur the master of science

[@sigma6656]

Peter Hamilton WOO HOO! Always fells good when your favorite Scifi author is mentioned. Of course, after Heinlein.

[@MrBloodySpirit]

I would so like to see a high-budget TV show or documentary series about these topics, with quality CGI, and Isaac writing and narrating them. I imagine it would not be for the casual audiences, but I would watch the hell out of it.

[@derrickthewhite1]

An active support structure that works for ring worlds. My mind is blown. I was wondering if it was possible, but couldn't figure it out. Well done. Though when you do it that way it feels like a tail wagging a dog.

[@miatacollector]

I just got back from work and I have been refreshing the videos feed like crazy. Happy Aurthursday! Thanks for the engaging and relaxing videos Arthur!

[@USSAnimeNCC-]

I wish this show up in science fiction movies or tv show

[@fatetestarossa2774]

me too

[@mirrorslash028]

That would be interesting.

[@cjk_02221]

That’d be fucking sick

[@9878stephen]

They live on one of these at the end of the movie Interstellar.

[@jamesyoung3565]

They have a few times

[@Levora]

Isaac, I have to say, I watch your channel rather sporadically, but each time I do return your video's quality seems to have improoved significantly. Keep up the good work, Sir.

[@azdgariarada]

Awww, that's so sad that Jerry died. :-( A couple of my favorite books are collaborations between Niven and Pournelle.

[@gemmel3197]

I remember reading Ringworld after borrowing it from the library when I was a young teenagers about 3 years after it came out. Larry Niven has remained a favorite author ever since.

[@jimwilliams1536]

Larry 'old school' Niven. Hamilton, Ian M banks. Serious A list writters..

[@oneheadead]

Reading ringworld is what made me find this channel 2 years ago! i was looking for more info on the megastructures and found this wonderful channel! thanks for the amazing content Issac Arthur! you're a G

[@Snoogen11]

It's impossible for me to watch any of Arthur's videos, without wanting to play stellaris.

[@samyamamoto6613]

My favorite thing about Thursday is watching Isaac Arthur pontificate about the possibility of fantastic future science

[@troisiemeoeil3651]

Another great video! One day I'd love to see you work out the science behind the manga/Netflix Series Blame!'s megastructure.

[@sithdoestat4432]

I learn more from Arthur than my entirety of physics study and I have studied that for 4 years

[@benjaminmjones5021]

Happy Athursday!

[@hansolo4017]

ARTHURSDAY HYPE!!! its the best thing to come home to after school.. got my exams in a few months and this really helps me unwind

[@while_coyote]

Listen up Sci-Fi authors, if you aren't already subscribed to this channel and busily stealing Isaac's ideas then you're in the wrong business! Thanks for another amazing Arthursday!

[@MrMartechi]

One of my favorite book series! I just love the concept and how its issues are adressed in the novels as well!

[@spacelingmartiens243]

Another great video Isaac, a hero of thoughts among mere mortals 😊

[@TalenGryphon]

I love Niven's work. And the idea of a world where I can take a car (alcohol burning cuz no fossil fuels on Ringworld) and trailer, travel for my entire lifetime and never see the same place twice is fascinating to me

[@michaeltuggle9757]

I thoroughly enjoyed Ring World and many of the series. I never considered a ring world as practical, but it was great fiction. I still have a paperback copy.

[@Ron4885]

Michael, I still have it as well in paperback. Wonderful read. It was very immersive. Wanted so much to 'go there' for a visit. And did, but just in thought. ;-) / I write numbers inside the the book cover to show how many times I've read it. This one has a 4. You might like Rendezvous with Rama.

[@JasonPurkiss]

I cant describe how this channel make me feel, thanks for creating this

[@isaacarthurSFIA]

Thanks Jason!

[@scottpaulhubbard8771]

Isaac Arthur you make it easy for anyone to understand the concepts of all you show just like to thank you for your great work keep it up mate 😀😀😀

[@isaacarthurSFIA]

Thanks Scott!

[@chosenmaple99]

“Greetings! I am 343 Guilty Spark. I am the monitor of Instillation 04.”

[@EMBer3000]

If you could solve the material strength question I've always thought that a habitation ring with one revolution per 24 hours and placed on an angle such that a plane perpendicular to the axis of rotation just misses the sun by a few degrees would be best. 'Natural' dawn, midday, dusk and night without any other structures necessary. It would be hella large but nothing compared to a full ring. Edit: This type of ring already covered in video. Oops.

[@manictiger]

I was thinking it'd be easier to use the sun's rays to power solar panels and artificial sky technology (which hopefully will have a near 100% electrical efficiency in the future.) Generally, less moving parts = better. A giant piece of armor with few moving parts is going to be a lot more reliable and the calculation to 1 Earth G much easier, than something that moves around in too many places. It would be far more resilient to micrometeors that get through the laser defense net, CMEs, supernovas, cosmic radiation, etc. Things that could theoretically get through Earth's atmosphere would not hurt a ring world fully encased in armor and maintenance layers (which could act like crunch zones as a last resort, though they're really supposed to be corridors for maintenance personnel, robots, nanites, materials, etc.)

[@Supreme-Emperor-Mittens]

I READ LARRY NIVEN'S RINGWORLD BOOK MANY YEARS AGO ... The Ringworld concept is also utilized in the Halo series. Bungie developers admitted to reading Ringworld and that's where they got the concept from.

[@totallyprofessional3571]

Isaac Arthur you should make a chart that show which videos really on other videos of your and other scores of information. It would help some of the new people.

[@isaacarthurSFIA]

Someone tried that over on the SFIA Facebook Group, it began looking a bit tangled and chaotic.

[@totallyprofessional3571]

Isaac Arthur Do you have link

[@mykobe981]

Isaac- Lol.. I bet! :P

[@mykobe981]

That is a nice problem to have. Too many IA vids!! =) I'm sure many of us envy you, Lol.. Ahh, the good 'ol days. ;)

[@Godfather061]

Isaac Arthur, I read “Ring World” shortly after it came out and by that I mean within a year or two. Although to be honest my memory of it is lapsed somewhat so I’ll probably have to look up the Kindle version or see if I can find it amongst my thousands of books that are packed in boxes around my house. As I recall the main character was a wire addict. He had implantation that allowed a trickle of electricity into the pleasure center of his brain such that he didn’t want to do anything except experiencing the extreme esthetic pleasure caused by the trickle of electricity. As I recall he was rescued just short of death by an alien that looks like it had two events one the opposite side of its body so looked like it could go in the direction, I can’t member the name of the though I believe they look something like a llama. The heads were actually heads they function more like eyes and hands and perhaps mouths. They were heard animal called the Puppeteers and the leader was called the Hindmost. Their strongest survival instinct was to run away. These aliens were highly intelligent and had invented a faster light spaceship drive and a spaceship hull material that was very close to indestructible and they were manipulating humans to rein in the Kzinti a tiger like race that was strictly carnivorous and would eat their enemies. I don’t believe the Kzinti factored into Ring World at this point in time. Just a note Ring World was constructed by the Pak Protectors who were the next developmental step for humans (if they came in contact with the pollen of a particular tree). Just another note that tree does not exist on earth.

[@isaacarthurSFIA]

The addiction issue is in the second book

[@Godfather061]

That is an example of the reason we can not depend on human memory. Human memory is cumulative, that is as humans we have a tendency to remember everything we ever saw or read about a subject as a single event even if the information came to us over a period of days or even years.

[@oldered5663]

Looks at all the engineering "ring-a-marole" involved with ringworlds...... " Meh.... Dyson Swarms are better!"

[@eclipsenow5431]

The sad soprano at the end of every episode reminds me of the Ood singing David Tennant's doctor to sleep. I'm so INVESTED at the start of every Isaac Arthur, with his one-liner headline sending shivers down my spine, and then so sad when it ends. Till next week!

[@victorrand8811]

Gonna need about 30 bil acres of window tint.

[@normoloid]

i read this book once when I was a kid in late 90s, and it was amazing. Nowadays all the old finnish prints are always sold out, signaling to me that im not the only one who loved Larry Niven's book and always has a spot on shelf, this book is basically read until the book starts to break apart. I would love to find one for my son to read, hoping that it would have that same effect as I did when I was a little boy.

[@trikkinikki970]

Just blowing up Arthur's spot but it's his birthday nextday Wednesday :)

[@isaacarthurSFIA]

Third Anniversary of the channel this Sunday too, and episode 100 next Thursday, though if one includes the 100k special that was actually today :)

[@trikkinikki970]

Oh, that's awesome. It's also 1 year since getting out of jail and finding this channel a few days ago, and also being on estrogen consistently tomorrow, which is affectionately known as my tranniversary to transgender folks :P I'm curious if you recognize me between commenting here and the facebook. But it's absolutely insane that you did the 100k subscribers like what, in July? You're already halfway to 200k. You had about 20 something thousand when I subbed. It's been absolutely delightful to watch what this channel has become, but your older videos have such a personal charm since you were doing the whole thing on your own. It's crazy you have like your own little design team to help you now. I love it.

[@JK03011997]

^^You should rename it the 150k special, then you still have a few days, or go for 157k that is ~Pi/2

[@trikkinikki970]

erik2000 Violation of probation for paraphernalia and other minor drug problems. Only in there for 5 weeks.

[@nomohakon6257]

And now the star of this day, Isaac Arthur!

[@ahblooloo8639]

Thank you Isaac. Is O'Neill cylinder video coming?

[@isaacarthurSFIA]

Possibly, we've discussed them so much here and there that the focus would have to be something like living in one

[@ebigunso]

Didn't you already do that in the Life in a Space Colony episode? Maybe the focus could be, why would people live in one compared to the other options, where would it be located and why, what sort of political structure would these habitats have either by itself or as a group of habitats.

[@antred11]

YES!!! O'Neill cylinders are my favorite habitat choice, as they seem much more in the realm of our technological / economical possibilities than those fancy ring-worlds.

[@michael3263]

antred11 Amen! I find the stuff that is actually possible within the laws of physics and conceivably reachable by human technology to be the most interesting by far. Consideration of impossible theoretical topics like Ringworlds is definitely useful and I wouldn't want to discourage that. However after a while it does seem a little silly that so much attention is being devoted to structures that are physically impossible to build. I prefer my science fiction not to violate the known laws of physics because that always kills my suspension of disbelief. I'm not a big fan of most movies for that very reason.

[@JK03011997]

@Antred11 The largest thing we can make from mundane materials like kevlar would have a radius of around 15% of the US width, or 50% of GBs length, to give that the area of earths farmland, it'd need to be longer than earths diameter. But it is possible from a material standpoint. And if you add an inner cylinder that provides light 1km above the surface, you'd need only 1.7% of earths air to fill it

[@robertmiller9735]

Niven actually addressed the question of regrowth of civilization on the Ringworld: the rock and soil is shallow, and there's no vulcanism, so unless the engineers planted them, there wouldn't be useful metal ores. (Turns out they must have; well, protectors think in the long term...) There is a large free-fall habitat in an Analog story, called Virga: just a sphere the size of the Earth. Unfortunately, that much atmosphere is opaque and the inhabitants have to use artificial suns. I like your hollow ring better. Ringworld was the first SF novel I ever read, and I still find Known Space compelling. But since the setting is the real star of the story, the characters and plot are rather flat and simple.

[@Regnilse]

Damn ringwolds are so stupidly big, like even with some type of internet on the ringworld well over 99 percent of the land, people, cultures and just everything would be practically unknowable to any individual.

[@isaacarthurSFIA]

Now imagine a Dyson Swarm or Alderson Disc, this is why I tend to assume 'Kardashev 2 Civilization" is a very iffy term when it comes to the civilization part.

[@anonb4632]

Greg Eslinger Or like present day Earth, the culture would evolve into a sterile Americanised mush.

[@barahng]

Anon B He means that it would be like 99% of Earth being uncharted and unexplored. Even with current tech it would take centuries to explore it all. It would be like the Late Bronze Age when the Mediterranean and Asia Minor was the whole world.

[@ephennell4ever]

@@anonb4632 ... With a million Earths worth of surface area?? *Maybe* after a few million years!

[@Peoples_Republic_of_Cotati]

The following problem may have been addressed in another video, so I apologize if I missed it. Atmosphere is restrained on earth by gravity. In an orbital Oneil style colony, atmosphere is restrained by the shell. But air and fluids are assumed to be also restrained to the inner surface by centrifugal force. But these are gasses and fluids which are still attracted by gravity; and they are pushed about by pressure and temperature differences. My point: how do we keep not so heavy stuff from eventually gravitating to the center of the habitat; as centrifugal force only works well in the long term with non-floaty solids?

[@colonelgraff9198]

ARTHURSDAY!!!!

[@syd4952]

I don't know why, but I think this might be my favourite video of yours.

[@GabrielTheExplorer254]

Happy Arthursday!

[@RandomYT05_01]

It was eventually brought to an episode of star trek lower decks.

[@awesomefacepalm]

You've made a great progress with your speech impediment :) I love to listen to your videos, it's very entertaining and educational

[@yankee5051]

Enjoyed your video on Ringworlds and their siblings. I read "The Mote in God's Eye" many years ago and still consider it one of the best SciFi )not onl 'first contact') novels ever written. Though I only read a couple of their collaborations, Niven and Pournelle (R.I.P. Jerry Pournelle) are probably one of the best writing duos around. I also enjoyed "Lucifer's Hammer." Keep up the good work with your videos. I enjoy them immensely.

[@tommymeeks9192]

Tell me how you manage to make videos 100x the quality of other science channels even though those channels are ran by dozens of people and this channel as far as ik is just you?

[@StepBackHistory]

Is there a reason we need to go to huge lengths to preserve the day night cycle?

[@Rando_Shyte]

Welp, I had to sub this was too awesome. I've found my people :')

[@Shaden0040]

Larry Niven's book Smoke Ring is the second book in the series. The first book is called Integral Trees, and the ring is not enclosed in anything but a natural ring of gas thick enough to breathe, similar to Saturn's rings of ice.

[@raggedclawstarcraft6562]

What if this thing will be a Möbius strip?

[@isaacarthurSFIA]

It's been discussed, especially if you can get the right amount of turns in to make a 24 hour day, but I didn't think to stick it in the script until way after the graphics were already planned and didn't want to try explaining that without a visual.

[@raggedclawstarcraft6562]

That's a pity. Would be awesome to have such a ring, especially if you don't wanna have stationary sun. The only we need is multiple platforms, that chained together, and support structure moving them in "roll" direction, while moving entire ring in "yaw" direction.

[@raggedclawstarcraft6562]

While rewatching this video I came to realization that this won't gonna work, because inertial force works only in one direction - outwards from the ring. So Möbius strip cannot be a thing, because everything on the "dark" side of the strip would just fall into space because of inertial force. Still, would be awesome to have double sided ring word that also mimics day/night cycle.

[@AlanRPaine]

I think it was in an article written by Larry Niven that I saw that it would be possible to create spin gravity inside a cylinder bent round into a ring say 1 AU in diameter. If the cylinder was 10 miles in diameter and the ring was 300 million miles in diameter then any short section of the cylinder would be very close to perfectly straight line so it could be spun around the centre line of the cylinder without creating excessive extra stress in the material.

[@thebeesknees1162]

The 99th Arthursday

[@paulbland5625]

Just went back to Megastructures 06. Discworlds. It is worth the re-visit supporting Ringworlds.

[@dylan522p]

What if a K3 civilization decided that they could last longer if they stay K3 rather than going k5?

[@vantablack6288]

o shit they could control the whole universe with that power

[@ebigunso]

Why is that?

[@michael3263]

erik2000 Most people don't understand what the scale really means anyway.

[@JK03011997]

A "type 5" would need to harness ~1300 times the amount of energy all stars in the observable universe emit. Or, if they had perfect energy conversion, they'd burn the mass of the local group tens of thousands of times per year, and without FTL, we can't really go beyond the local group because of dark energy [Used the number from this paper arxiv.org/abs/1312.2587 ]

[@voicetube]

One of the I guess I would say defining moments of my life (or certainly anything really life-defining that ever happened at a party) was when I met… Yes MET Mr. Larry Niven at a meetup/party in Los Angeles of people who are/were at the time, very much into the (then) emerging technology-driven device known as the Segway (I was an early adopter and still have my first Gen-1 unit!). It was almost like an out of body experience speaking with the author of one of my favorite science fiction novels of all time (indeed, RINGWORLD).