Spin Gravity Compared

[@keipfar]

Handwavium, the miracle material!

[@Feefa99]

Gravity plating with condensed material in micrometer strings held by electron degeneracy pressure from collapsing into black hole.....or something more even technical.

[@Extra.Medium]

You can do anything with enough handwavium and renderite

[@anticlaassic]

Unobtainium

[@KnightRanger38]

@@Extra.Medium Don't forget "Wantum Mechanics".

[@Extra.Medium]

@@KnightRanger38 ooh that's a good one

[@solandri69]

1989. I was in college (undergrad) and joined the Traveller Mailing List. That's a sci-fi pen and paper RPG. The list started a group adventure about visiting a newly discovered ringworld, and I got put on the team to make content for the ringworld (yeah, three of us tasked to make 3 million Earths of content). I'd gotten my hands on some 3D rendering software (we won't mention how), and tried making renders of what it would be like to actually see the ringworld, complete with fractal land, ocean, clouds. Remember, this was 1989. My poor little 80386 PC (with no math coprocessor) took 18-22 hours to render a single 640x480 resolution image. This was all running under DOS - no multitasking. Meaning my computer was completely occupied and unusable while it was rendering. Another guy on the list tried using his work computer (a Sun Sparc I think) and it completed the render in 17 minutes. Those two factors made me give up after rendering just a few images. It's nice to see the same thing rendered with modern hardware. Thanks for the trip down memory lane.

[@PiDsPagePrototypes]

3D app, late 80's, 386, no co-pro so 386-SX, probs 25MHz clock.... maybe 33MHz.... Real early Lightwave? I used POV-Ray and the modeler Moray back in '93 on a DX5-133, and a basic dive to the planet surface animation at 320x240 at 12fps took a couple of weeks to render, when my parents didn't turn the PC off at the power switch while I was in class.... Your pain is well understood. :)

[@VerumAdPotentia]

Ah, Traveller, where, "You haven't lived, until you've died in character creation."

[@OverviewEffekt]

Even this was hard to render on modern hardware, though not that bad. About an hour per frame on my gtx 1080 (any crypto bros out there willing to donate a video card? Lol) and had to use the (wonderful!) free render farm sheepit. It’s really the glossy floor that makes it hard. I had to use some tricks to minimize the light bounces in the floor. And had to render it multiple times to get all of the glitches out. I made the Ringworlds procedurally using blenders geometry nodes (which I’m addicted to) and it was actually pretty fun to do it that way. Could have been much better(still a few glitches). But it’s always a time/quality equation you have to balance.

[@ravenmoon5111]

@@VerumAdPotentia or became so old you had to retire before you ever played

[@VerumAdPotentia]

😆

[@tomsko863]

For many people, the cylinder space stations from the Gundam series are iconic and a very important plot point in the series. Thank you for adding Babylon 5!

[@jedisalamander2457]

Yeah the colonies in Gundam are pretty cool, was almost hoping they'd make an appearance but wasn't expecting it

[@pauljensen5699]

THE GUNDAMS WILL SAVE US ALL!!!

[@Janx14]

@@jedisalamander2457 I was thinking the same. Though they're very close to the Ramma (especially the closed-type ones).

[@jhnoakez]

Yeah quite the oversight to not include Gundam. The designs were ripped direct from Gerard K. O'neill's work which is the seminal documentation on spin gravity space colonies.

[@pauljensen5699]

@@jhnoakez They even called them "O'Neil cylinders".

[@Cyberdactyl]

You explained everything pretty well. One aspect you kind of overlooked is WHY someone would get nauseous on a smaller spinning hub like the 2001 example. The film shows Dave Bowman jogging inside. If he wanted an easy jog, he would jog anti-spinward. If he wanted a rigorous jog, he would run spinward. His ~10 feet per second added to the hub's angular velocity would increase his 'weight' noticeably. Also, just standing up from laying in bed. The inner ear would experience a noticeable centripetal acceleration change. And as mentioned about Bowman, moving spinward OR anti spinward would also wildly change the inner ear's acceleration.

[@Akio-fy7ep]

Betting people could get used to just about any rotation after a while. None of the experiments ran for any length of time.

[@Cyberdactyl]

@@Akio-fy7ep Moving spinward, antispinward, radially in and out. . .all would effect the inner ear noticeably inside a small diameter hub. It would be like being aboard a smaller ship in rough seas. *One big difference in a hub* YOUR movement controls the acceleration fluctuations in a hub by moving in ANY direction as opposed to the sea controlling the acceleration change on a ship. NOT controlling random accelerations is MUCH more nauseating. So yes, I agree. I imagine it would be moderatly easier to get over the "seasickness" on a hub with a smaller radius. As is said in the video, once the radius gets to around 80 meters and the spin speed provides around 0.5g, the changes in accelerations by your movement become too small to notice unless your on a vehicle riding the hub's inner surface.

[@robgilmour3147]

the Russians did a bunch of longer term experiments on Coriolis effects and they found that most people just get used to it after a week or two

[@KarolOfGutovo]

I imagine that on a long enough timeframe at least some humans probably have the capacity to get used to the patterns and live problem-free long-term even at high-RPM. Probably they'd even get a sense for which way is spinward, from the tiny constant movements and the slight forces the spin would cause.

[@OverviewEffekt]

Yeah, I totally glossed over the Coriolis effect to focus on the other factors. Also some astronauts are legends made out of unobtainium and could handle anything. Probably Dave was made of this stuff.

[@thestudentofficial5483]

I just realised Endurance's 12 modules looks like a clock which ties in nicely with the whole theme of time in the movie.

[@d3vitron779]

tick tock tick tock *organ begins playing*

[@judet2992]

Yeah and it spins clockwise.

[@barbarossarotbart]

It reminds me of the Lab Ship (Type L) from Traveller.

[@BenJuan26]

Also 12 disciples, 12 tribes of Israel, 12 crew of the original Lazarus missions. Lots of religious callbacks in the story. The time parallel is very fitting though.

[@xvhkgreen6297]

Gravity has never been proven; Never been detected, Never been observed. You need to prove against all other rationale that the reason an object drops is uniquely the act of gravity and nothing else. -You have to prove how all matter attracts all other matter indefinitely, and how that concept is why things fall. Helium balloons disprove gravity. Bumble bees disprove gravity - Their wings can't support their body weight. Gravity is a scape goat for all things that cant be explained

[@Albtraum_TDDC]

I remember 3 decades ago, when I was in Mechanical Engineer Polytechnic School, I got interested in rotating space stations (ring type) and worked out all the math formulas for stress on the shell depending on rotation speed and diameter and materials used (tensile strength and density and useful cargo on top). I found a NASA white paper and I had done it all right, I was so proud. I even found a small typo on their paper and emailed the authors. Back then Internet was so small, they actually replied >.

[@rharbarenko]

Finally! someone made ringworld to "scale" I wish you put a pov camera on every structure for comparison. very cool

[@OverviewEffekt]

Yeah i almost did that. I wish I had. But it took me months just to get this right and I didn’t know it would go viral… wish I had.

[@gnericgnome4214]

What thought went through my mind is that when you're speaking of these truly huge structures, could you not achieve gravity rather than by spin, by thickness of the ring? It's not Earth's spin that gives us 1g, it's her mass underneath us.

[@podboq2]

​@@OverviewEffekt ‘viral’ with less work isn’t a bad thing, is it?

[@GeoffFrizzell-kz3rg]

Another thing to consider: How about a ring that is spinning more slowly (only for stability, perhaps), but closer to a sun -- so close that the actual gravity of the sun is pulling on it with the force of 1gravity? The math would be the same as for Ringworld, but the living space would be on the outer surface with mirrored lighting instead of potentially dangerous additional moving parts. There would still need to be something like the ramjets to nudge it in place but the bridge analogy Niven used for construction and strength still applies. 🤔

[@TheArklyte]

First time we encounter Halo in Halo CE, we see it with a PLANET in the background. Rampant gigantomania was added later, likely another fault of allowing novel authors to parasite on your IP.

[@andrewhofmann5453]

I love that you referenced "Project Hail Mary", such an unsung hero of books.... And the Bobiverse!!!! Great references in here!

[@mahatmarandy5977]

I get so excited when someone mentions B5. It’s been 30 years, but the show still gets so little love. Thank you for doing this! The Agamemnon from B5 is a pretty cool example, BTW. It’s Captain Sheridan’s old ship, about a mile long, with a large revolving section to simulate gravity, but rather than be a wheel like we commonly see, it’s basically two pie slices connected at the center, similar to the Leonov from 2010. Oh, yeah, and the Leonov is kinda cool, too, I guess (Forgot about it until the Agamemnon reminded me). Not saying you should do another video on the subject, I just thought I’d mention it. Again: Thank you for doing this!

[@Xingmey]

it's just excellent - that show is something else... just started another rewatch of that show

[@mahatmarandy5977]

@ i always rewatch it a little different if I can. One year I rewatched it with the movies in their proper places (Which is rough because Thirdspace takes place *inside* a regular episode) Another time I watched it, I stopped at “Objects at Rest,” then watched River of Souls, Rangers, call to Arms, Crusade, lost Tales, and THEN Sleeping in Light. This last time through I just skipped Season 5 entirely, and just jumped from “Rising Star” to “Sleeping in Light.” Each time it’s caused SiL to have a different emotional impact on me.

[@KILLERAOC]

Agamemnon and the Omega Class ship design is a sci fi classic.

[@Akio-fy7ep]

Be sure to catch Star Wreck, then, from the creators of Iron Sky.

[@harriehausenman8623]

Bablyon 5 was really good. The whole Shadow arc was amazing.

[@DecidedlyNinja]

Ceres would 100% definitely disintegrate if it was spun up like that. Even solid rock behaves almost like a liquid on planetary scales, thanks to the square-cube law.

[@alexjamesmalcolm]

In the books I believe they covered the dwarf planet in some structure. I might be confusing that with the space dock that was located at the pole though.

[@Khannea]

You can 'easily' submerge a train track some miles under the surface, and suspend an endless train right under the surface. The train runs on a maglev suspension on its uhm "ceiling" ? This easily creates gravity. I am pretty certain the solar system can be colonized with "embedded" cylinders, little spinning like centrifuges. Angle them a little, so their conical shape compensates for the gravity of the asteroid or moon. In fact you can 'easily' replicate Earth's surface on the moon by constructing endless such embedded cylinders below the surface. Make em as big as a typical O'Neil cylinder (I built one together with Simon Deering in 2010 for Transvision conference) and you can have about 50% of Earth's surface - but with garden/eden level of comforts - so easily a hundred billion people.

[@Khannea]

Literally applying the same metric for Ceres, a dwarf planet like Ceres could have a population of, assuming one "layer" of habitats "only" (....) literally One Earth - about 8 billion people, living with a population level and relative spacing of The Netherlands. Now if we were to start stacking the rotational habitats, plus a solidly reinforced structural envelope or "casing" on top of one another, say four layers deep, (some 20 kilometers on the moon) we can have hundreds of billions of people living on the moon. But at that scale the heat emitted by each habitat with all the BBQ's and swedish sauna's and such would become a problem. If we build habitats all over the moon, 4 levels deep, and we assume several times USA levels of heat consumption, the waste heat could make the surface glow on the dark side in infrared at over 100 degrees Celsius.

[@certaindeath7776]

@@Khannea i see, an isaac arthur enjoyer :)

[@SteinGauslaaStrindhaug]

My head canon is that it's not the whole dwarf planet that is spun up but underground centrifuges that is used to add to the natural gravity rather than trying to completely cancel it and reverse it as spinning the whole planet would need to do.

[@ln5321]

For anyone who hasn't read it, Project Hail Mary is excellent. I was a bit skeptical of it going in, but it ended up being my favorite of Andy Weir's novels.

[@kellymoses8566]

The audiobook is fantastic.

[@chrisastral1]

Just waiting for the movie now

[@georgeofhamilton]

Nah, it was kinda lame.

[@insu_na]

I loved it but it had a few glaring logical issues. I'm still checking regularly when the next Andy Weir book is coming, tho 😅

[@kellymoses8566]

They are making a movie out of it starring Ryan Gosling. I really want to see how they portray rocky. I hope a combination of excellent puppets and CGI

[@HojoNorem]

The Coriolis, Orbis and Ocellus starports from Elite: Dangerous are worth mentioning.

[@EzriPrism]

Coriolis would be especially interesting too look atbecause its a cuboctohedra

[@Monody512]

Oh hey, the exact comment I was about to make! But yes, those are interesting because they actually have distinct rotational periods from eachother, and all their stats are listed on the wiki. Also Orbis class starports can have two different sizes of habitat rings spinning at the same rate, meaning they'd have different internal gravity. (I say "can" because they're modular and not every Orbis has both or even any types of habitat rings.) Elite: Dangerous does also commit the physics sin of spun-up asteroid bases, but natural asteroids in the game already spin unrealistically quickly, so I might give it a pass. :P

[@OverviewEffekt]

I couldn’t find any specs on them. Is there?

[@dallinmelton5679]

Also Ixion would be cool

[@VitorHugoOliveiraSousa]

@@OverviewEffekt just google "Elite Dangerous space stations" and go to the wiki of the game, there is specs for all types there.

[@koro_kokoro]

The halo ring is a ring because it’s not REALLY a space station for its purpose. It’s a super weapon to eradicate all life in a radius

[@benny_dryl]

All hail the colossal space laser

[@BlazerManiacNumber96]

Halo also isn’t hard sci fi

[@Daimo83]

Spoilers lol

[@abhinav-v2i]

Oh thank you so much! I left Bobiverse on the second book. If only I had known this would be coming later. I loved this size comparison. The graphics here are _chef’s kiss_. Great job altogether.

[@MomirBacic]

Honestly the third book is the worst one imo, fourth one is fun so far

[@asherwiggin6456]

First one is the best one but they’re all pretty good.

[@Golinth]

@@MomirBacic I really enjoyed book 5, book 4 was too slow for my tastes and I didn’t enjoy the starfleet plotline. 1, 2, and 3 were great though, imo.

[@sagittariusa2008]

Finished 5 recently. Looking forward to the rest of the possible decology+

[@RedBlaze45]

Your rendering skills really improved. Good job pal

[@OverviewEffekt]

Thanks. My rendering time also increased… lol. It’s mostly a time/quality trade off. I’m working on a gtx 1080 here…

[@scottjohnson9799]

7:21 So glad to see The Culture getting some love. Some people daydream about living in Middle Earth or the Old Republic or what have you. I daydream about living on Masaq Orbital.

[@slateslavens]

I was thinking one of the GSVs, personally.

[@KJTB8]

I always preferred the ex ROU Psychopath Class - If I could ever get one to agree to me living on it!

[@agonefire]

What’s the appeal of being a pet to a bunch of AIs?

[@Shrike200]

@@agonefire I never got the 'pet' vibe from all the books. More like 'we like other sentient things around, and we'll try and keep everything ticking over while everybody (including us) does their thing' from the AI's. Yes, it's technically a 'benign dictatorship' I suppose, but with god-like AI's that like having you around, it could be a lot worse?

[@marclemieux4902]

@@agonefire they give the best belly rubs

[@Warden0190]

There are the Iconian Dyson Spheres from Star Trek The Next Generation, we even get to see the Inside of 3 In Star Trek Online, The original Jenolan, the Solanae and the Herald Spheres. Star Trek also has Yorktown Station which also has a ton of handwavium involved but it is an interesting design with how it uses all of space with the artificial gravity letting people live on the different sides of those tunnels in it.

[@zerrodefex]

Yorktown Station was just absurd for something that was made before the time of the Original Series. I don't care if it's the alternate timeline, that thing was too advanced even for the ST: Picard setting.

[@kellymoses8566]

Yorktown Station was far too advanced for human technology in Star Trek and is a good example of how the creators of the movie completely failed at world building

[@RocketToTheMoose]

Was the Dyson sphere really Iconian? The extinct civilization with teleport technology from season 2, I think?

[@MegaZeta]

Sorry about the replies who think Star Trek is hard sci-fi. I assume literal children…?

[@MegaZeta]

@@RocketToTheMoose The Dyson sphere’s creators never came up in the show. The online game tends to make the fictional world smaller, more trivia-mongering and less imaginative, so the idea of the entirely separate Iconians making the sphere might come from there.

[@cmudd9788]

Glad you included Rama in this. The Rama book series is my favorite book series and I rarely ever hear anyone talk about it.

[@dexterford8094]

There is a movie in development based on the book "Rendezvous with Rama" by A.C. Clarke. I just hope the movie lives up to the standards of the book.

[@Becvar80]

​@@dexterford8094 Just found out this is to be directed by Denis Villeneuve. After what he did with Dune, I'm excited for the prospect of Rama.

[@cmudd9788]

@@dexterford8094 I remember hearing something about that recently. I hope they get it right. I've been telling people for years that it would make a great movie or TV series. I think a TV series would be the way to go. Especially when it comes to The Garden of Rama. There's just way too much to fit into a movie. A movie for Rendezvous with Rama would work if it was used as an introduction for a TV series that covers from Rama II onward. They could easily get 8-10 seasons out of it.

[@Daimo83]

Because it was boring

[@Bellerophonmodeler]

Kudos for making a super interesting video on a subject close to my heart. You touch on the angular velocity limitation of five or six RPM, but also the small size of Discovery means the crew feels significantly lighter at the head than the feet, not a comfortable feeling at all. The Coriolis effect would be wicked, too. Imagine playing centrifugal ping pong!

[@tylerhloewen]

The reason for the "spiral tunnels" on Ceres, is that the centrifugal force is being used *additively* to the gravitational force, not subtractively the way you depicted it. This creates increased perceived gravity along a cone shaped surface into the interior of the mass with the poles of rotation at the center of the cone and the point towards the center of the mass. Those tunnels are built along that conical surface. You could also live on the cone at the other pole with the same perceived gravity. The part that's unrealistic, is that the cone should be much more shallow, since it's only a mild increase in gravity. Also, Ceres is definitely not a "rubble pile" asteroid. It's surface is well studied and photographed up close at this point. It is quite solid.

[@CODENAMEDERPY]

Ohh, so Ceres itself isn't being spun up, just the cone section?

[@harbingerdawn]

@@CODENAMEDERPY No, the whole thing is spun up, but when you calculate the combined effect of the spin with Ceres' own gravity, the ideal place to build tunnels to utilize the gravity is along the surfaces of those cones, which are mathematical illustrations and not physical structures.

[@CODENAMEDERPY]

@@harbingerdawn Would those tunnels be at the rotational poles?

[@ABaumstumpf]

"is that the centrifugal force is being used additively to the gravitational force" Nope. There is no surface where the gravitational and inertial (centrifugal) forces would add up positively. Way worse once you notice that the proposed force due to rotation is the same as surface gravity: It means that the regions furthest from the rotational axis of the planet are no longer bound by gravity and the whole thing would rip it self apart. Gravity always is an inward-vector, centrifugal inertia is always outward. The best you can do to "increase" gravity is to STOP all rotation - for earth that would make a person on the equator about 0.3% heavier - negligible.

[@OverviewEffekt]

The arrows are indicating the centrifugal force, not centripetal. Which might be a little confusing, but I thought it made the point clearer. It all varies on how big the tunnels actually are, and therefore how much centripetal falloff there is both laterally and towards the core. Either way, a tunnel circumnavigating the asteroid, like the Neom The Line city concept, would be ideal. Unless the tunnels are so small that the lateral falloff of acceleration in a cone shape is negligible.

[@davidg5898]

When you mentioned the potential to get dizzy, I was surprised you didn't go into some of the weirder aspects of gravity via rotating cylinder: from the perspective of someone on the "ground" -- part of the rotating inertial frame, as opposed to an observer watching the ring rotate from outside -- ballistic trajectories aren't the same as in a mass-induced gravity field. The smaller the ring diameter, the more noticeable the deviance from "normal" gravity.

[@Gunbudder]

9:21 I met Larry Niven once, and he told me that someone had made a scale model of the ring world at a convention he went to. crepe paper was used for the ring because it was the only thing cheap enough to make that massive of a circle lol. Also, Larry is one of the nicest guys you will ever meet. i had no idea he was even an author and i wasn't familiar with his books. He gave me a copy of his most recent book at the time after i talked to him for a bit

[@dinoblaster736]

The visualization of heavens river really puts into perspective how lucky the bobs were when they were looking for benders matrix

[@victor6250]

How was it they located the section he was on? I forget. Did they just scan until they detected him?

[@harriehausenman8623]

Good ol' Anek-23 🤗

[@anticlaassic]

@@victor6250well they entered close to the only active of 9 gates in the outer shell. In that sense, they were still lucky, but not „with the Jackpot 23 thousand times over“ lucky. They simply saw the sentry drones preferred that gate and assumed Bender was carried through the same way. From There the resistance stole bender and saw now reason to move him further than the next regional headquarters in halebs ending(?).

[@anticlaassic]

@@harriehausenman8623i‘m still not quite at ease with him. But the fact he hates beer is pretty endearing 😂

[@harriehausenman8623]

@@anticlaassic give him some slack. he had a really tough youth 😄

[@williambell4591]

Thank you so much for this - PROPS! The Expanse was some of the BEST sci-fi of my LIFETIME! I never finished all of Babylon 5 but I've been stream watching more of it this year. Halo - yep one of my fav games as well - you've covered a lot of the things I've enjoyed over time - thanks so much for this look into the science behind the fiction!

[@TheRealVastile]

So glad to see The Culture series get it's due here.

[@slateslavens]

agreed.

[@TCBYEAHCUZ]

yep

[@81brassglass79]

I'm almost finished with the final book of The Ring world ser ies and I got to say they are fantastic. Definitely recommend reading them all. I only recently discovered that he died a fair amount of time ago and was born way before I thought he was. 😅 He was a creative mind truly ahead of his time. Rest in peace, Larry, thank you for the stories. 🙏

[@atimholt]

There's some way crazier stuff outside Science Fiction, in the realm of speculation, hypotheticals, and pure world-building. Isaac Arthur on KZbin has some fantastic videos on the subject, and you can find all kinds of blogs and wikis that go over some crazier ideas with viability ranging from fantastical to clever and actually reasonable.

[@AlbertaGeek]

Love Isaac Arthur's content.

[@Orlando_from_The_Bronx]

The Gaia Trilogy by John Varley (books: Titan, Wizard and Demon) takes place in a Sanford torus that's an actual sentient entity. It's an extremely fun and bizarre trilogy that's hard to characterize.

[@uncletiggermclaren7592]

The Gaea trilogy by John Varley deserves a mention. Titan,WIzard, Demon are the book's names. Humanity finds a fairly stealthy artificial satellite in orbit around Saturn. A crewed mission is sent to Saturn, and detects an artificial but LIVING Stanford torus, 1200 kilometers in diameter. It has an artificially dark surface ( vanta black before that was a thing ), and they can't really get any information from it, they theorise ( correctly ) that it is deliberately covert. As they approach they detect that it has extremely low mass, so is obviously hollow. It is under spin, and as they pass by to measure its mass distribution, it exudes tentacles like a cuttlefish, and gathers in the earth-ship. Hy-jinks ensue. Turns out to be an extremely old genetically engineered INTELLIGENT artifact, part of some civilisations' attempt to colonise the Galaxy. And they are successful, the Gaea the ship encounters is one of thousands in our solar system, and it is in contact with a countless community of others spread out across the galaxy. The Gaea's arrive in a solar system as a seed, if they land on resources, they slowly grow up to size by much the same methods as a tree. In the process they eat up the planetoid they have landed on. When they are fully loaded with the amount of resources they will need to thrive, they put themselves into orbit somewhere that they have a energy source, they do not need much. They ensure that their reaction mass ( the parts of their landing body that they don't need ) is launched at a tangent from their circumference, to give themself spin. During this phase, they are compact. When they have made their orbit, they begin to inflate, melting the frozen gases they have gathered. They also grow and launch countless seeds, aimed extra-solar, again from their circumference to spin themselves up. Inside they have complete and detailed control of the ecosystem that lives in the shell of the living world. And they have near miraculous genetic libraries and genetic engineering ability, and listening to Her "Sisters" among the stars, the Gaea can grow a vast library of creatures, from virus size up to whales.

[@DavidCowie2022]

Gaea Trilogy mentioned! I was at university when those books were new, and they were some of my favourites. One of my friends even went so far as to make a homebrew RPG with a Gaean setting.

[@alan-sk7ky]

Do not visit Cronus, he is quite insane these days...

[@morismateljan6458]

I always wanted too see these turned into movies, but I guess there's too much sex.

[@jebmiller4523]

This video is AMAZING and sets the standard for all the "to scale" type videos out there. Great narration, entertaining and informative, good visuals, all-around banger.

[@Itsallwrongbutthatsallright]

Arthur C Clarke's books are highly recommendable. You just get sucked into these books, and his ability to describe something extremely complicated in very easily understood language, is amazing. The Rama series is a good place to start. Remember to eat, drink and sleep now and then as you just can't put his books down ! 🙂

[@GrendelSheperd]

It wasn’t long ago where a comment made a day after you made a vid wouldn’t be buried at the bottom of 800 comments. Very nice work friend. Love that you got the Bobiverse in there at the end. ✌️

[@mike_y0st]

DYSON-SPHERE’s NEXT PLZ!! Onyx or Trevalyan, from Halo, is ridiculously huge. The internal surface radius is approximately 1 AU.

[@SiriusSphynx]

Please keep making content. Your presentations have a perfect format and your subject matter is unique. I struggle to find descent channels like yours. Another channel that has a similar feel as yours is an engineer that talks about space station designs in video games. Just like his, yours are comprehensive and detailed and it just scratches that itch other content creators never seem to be able to manage.

[@Pur4r4ng4r123]

Im Commander Shephard, and this is my favorite gravitational demonstration video on The Citadel!

[@PaddyWolfe]

i figured the ringworld books would get one of the last mentions since you were going by size. loved the whole "ringworld is unstable" story. one of my favorite Niven anecdotes.

[@JustinMShaw]

I thought I remembered Niven claiming that he used to attend parties that local scientists also attended, and he got ideas for his stories, as well as help getting a hard sci-fi reputation, from them. And of course he did invent a fictional material to hold his Ringworld and its shadow squares together and in place, and described its properties.

[@idjtoal]

were the shadow square wires made of scrith also ? not saying they weren't, it's been a while since I read any of those.

[@JustinMShaw]

@@idjtoal I forget if they ever got a close look, but do remember that they made that assumption. They also knocked a piece of connecting string loose in the first book, which proceeded to fall on and cut to pieces a civilization on the ring floor. In that case I think they confirmed more strongly that it was scrith.

[@AlbertaGeek]

@@idjtoal They were. The Pak used it for pretty much everything.

[@Akio-fy7ep]

@@AlbertaGeek It should have been superconducting.

[@AlbertaGeek]

@@Akio-fy7ep Yes, but that would have made it the _ultimate_ unobtanium. Had to leave something for the plot, right?

[@ErrantLight]

Thistledown in Greg Bear’s Eon would be interesting to see in your fantastic video treatment. Even though the humans in that universe are advanced enough to alter universal constants, the infinite length of The Way would be a fascinating analysis. Keep up the great work!

[@Akio-fy7ep]

I was disappointed to see no Bishop Ring, defined as the biggest compatible with hard SF. The limiting factor is tensile strength of the the floor material, which is thus the most important detail of any design, limited by the strength of a covalent bond. Interestingly, the limiting diameter is proportional to the length a cable of the material can hold itself up, supported at the top, under the acceleration you want. For 1G, which is the only one we know is compatible with human biology, it comes out to about 1000 miles, and turns in something close to an hour. It is big enough that, with walls, you don't need a lid over. Inner surface area is New Zealand to Italy. You would build it as a thin ribbon, spinning it, and then widen that. Widening it from the center line would let you keep the walls up that hold the air in. At any time there would be long triangular holes along the center line with domes over them: cut some at the point, weld in a plate at the back, repeat. Any sufficiently advanced culture will not be reliant on a star's radiation for energy. Its biggest problem will be radiating away the waste heat from its high-energy operations, making cold the most precious commodity. It will locate its operations no closer to a star than its Kuiper belt, and that close only for ready access to material resources absent in interstellar space. Bishop Ring, given that it is actually possible in principle, deserves its own detailed episode. Certain practical problems remain to be solved.

[@DavidCowie2022]

"Certain practical problems remain to be resolved." A simple matter of engineering!

[@DajesOfficial]

"Any sufficiently advanced culture will not be reliant on a star's radiation for energy" what? Stars have more energy than the rest of the system combined. No sane culture would throw away these growth opportunities

[@goldenbear8696]

“Ringworld” is a fantastic novel- as a sci-fi enthusiast it’s my all time favourite.

[@Jan12700]

There is also Outer Wilds with the Echoes of the Eye DLC. There the stranger is a spinning Space station. It's about 500m in diameter. As well as Stellaris, where you could find and build a Ring around a planet or even around a whole star.

[@spacekowboy1539]

OUTER WILDS MENTIONED LETZ GOOOO

[@ZumoDePapaya]

I was about to say this exact thing

[@TheLostMilkman]

I found it so cool when I managed to get into the center and it was actually a 0g areas. The attention to detail is so impressive, especially because you have to piece everything together without any written history. I loved how they used heaters to make the still water warmer than the rest of the river, for example.

[@Originalroninstorm]

The Ringworld Series is amazing. One of my all-time favorite series. Don't hear much about it anymore tho, unfortunately.

[@genericusername5909]

It’s tiny in this context but the citadel in mass effect

[@justinecooper9575]

What about the living quarters of the ship, Europa One, in "Europa Report"?

[@FScott-m1n]

Ringworld is mind-numbingly big. A 95 mile segment of it has the same area as all of the land on earth, and there would be ~6.3 million of those segments. Driving 24/7 on a highway straight across the width at 70 mph would take 370 days. An unbroken airliner flight would be in the neighborhood of 50 days.

[@jackemled_but_gay]

Just take the space train thing that runs along its edges! Even that would probably still take forever to go around the whole thing though.

[@BinkyTheToaster]

Good thing the ships are fast, "space pilots tend to forget that Mach 4 in an atmosphere is _fast."_

[@cjeam9199]

@@BinkyTheToasterthat’s still not fast enough to visit your friend who lives on the other side though.

[@leroyblom2851]

​@@cjeam9199 easy,.. just jump out of gravity, fart, wait, wait,fart the opposite way, land tadaa

[@BinkyTheToaster]

@@cjeam9199 Mach 4 isn't, but this is a spacecraft we're discussing; it'll make like Mach 20000 before you have to engage the hyperdrive to go faster.

[@ytbit]

I was kinda disappointed that you didn't include Gaea (from the trilogy by John Varley). She's a 1,300 km diameter Stanford torus.

[@Creepyslandofdreams]

Rama and Hailmary mentioned 😊

[@someguy-k2h]

The artwork in this is really impressive. I have to say you did a really great job on this.

[@longsleevethong1457]

Yeah except this principle is garbage. It’s a fairly tale. It absolutely does not work. Weightless is weightless. Spinning a room around you doesn’t “simulate gravity”

[@someguy-k2h]

@@longsleevethong1457 If that was the case, then why do NASA, US Navy, US Air Force, US Space Force, and every other space and military organization in the planet use centrifuges to train personnel in high G environments? For that matter, why do any of the thousands of companies across the world that need to quickly separate suspended solids use industrial centrifuges? If this were a "fairly tale" (sic) don't you think much smarter people would have noticed that already?

[@harriehausenman8623]

OMG! Not only was I just reading about megastructures and compiling a table to compare them, but when I saw *Heaven's River* , my jaw dropped. Bobiverse is the best! 🤗

[@TheArklyte]

I'd suggest adding Tiqqun from Ixion. Judging by the size of available compartments, it could probably fit the 2km diameter criteria. Although it's a ship, not a station.

[@ToroCH]

The cylindrical gundam colonies from the UC timeline, or the hourglass shaped colonies from the Gundam SEED timeline would be nice contenders. They all seem pretty realistic.

[@GeoffFrizzell-kz3rg]

I also didn't realize why we hadn't just built the dam things already until I saw Collapsing Land and The Scar of Space -- holy crap! The last 25 years is proof enough to me these things absolutely have to be able to split completely into survivable modules on vectors that definitely allow them to avoid becoming dangerous Earthbound debris. I'm not even happy about large habitats at the Lagrange points anymore.

[@hello-rq8kf]

cute konata pfp

[@Soldier4USA2005]

This was pretty awesome and easy to understand!!! Thank you for sharing and your rendering skills!!

[@silentraven9792]

8:20 I do not get the day/night cycle bit. In my mind, a ring inherently cannot cast a shadow on itself while the light source is a sphere within the ring. If you ever wanted to do a follow-up vid with a graphic for that, you'd be da boss EDIT: Ah, nevermind. The next graphic cleared it up! I thought the middle of the first ring example was the sun. I got you now. Great work!

[@man-from-2058]

I thought the same exact thing because Ring World is just engraved in my mind, no instead it's just a kinda small station orbiting a star.

[@Akio-fy7ep]

@@man-from-2058 The shadow squares should have had more-clever shapes, to emulate twilight. Perforated at the ends, maybe.

[@seailz]

Amazing video, very interesting!

[@oatlord]

Imagine being in the maintenance department on the ring world.

[@chrislaf89]

I think you'd have a sector you're assigned to, rather then being sent all over the place

[@fantabuloussnuffaluffagus]

"The Ringworld Engineers" goes into this very thing.

[@oatlord]

@@fantabuloussnuffaluffagus I guess I'm not as clever as I thought.

[@ddegn]

@@oatlord Still, the maintenance was a huge problem. You're right to wonder about it. Please pass me some of that Tree-of-Life root and I'll help with the maintenance myself.

[@kellymoses8566]

The maintenance and repair of the ringworld become major plot points in the sequels. One of the reasons it works is that the people managing it are superintelligent immortals genetically compelled to keep alive anyone genetically similar to them.

[@apennameandthata2017]

Why is the tangential speed an issue? It only has to accelerate the material in the ring at 1 g. Is tension the issue? If so, why not say so?

[@nancy2568]

Been a fan of Taylor and Weir for years, I am glad to see them getting some proper nerdom recognition! I did some calculations of a Dyson sphere, I think I came up with 21 billion times the surface of the earth, But I solved the gravity issue with mass by making it have a 12k km thick shell. I abandoned it though because that amount of mass could actually alter the internal gravitational forces of the star it surrounded. Fun thought experiment though.

[@ThomasZammit]

Please keep making these types of videos. You are quite clearly blowing up. 250000 views in a day is insane.

[@Lantalia]

You forgot the Alderson Disk, one example of which is in Missile Gap. Then again, it generates gravity the old fashioned way

[@jacobp8294]

This video was awesome! Like a size comparison (one of my favorite visuals in a video) combined with a scientific analysis of fiction. Really lovely stuff, would love to see more of it in the future. Thank you!

[@jhnoakez]

How do you make a video about science fiction spin gravity and just not mention Gundam at all? Legit the most realistic and prolific examples of spin gravity in science fiction and just... not even on the map for you?

[@RoyBeerZ]

I didn't know I needed this, but here I am. Subbed!

[@verado2007]

The one thing I wish you did included was the Buthandi (sp?) from Schlock Mercenary. Probably not appropriate for this video because they generate gravity through fictional science. But it is a stellar enclosure which according to the author, the name translated into English is, "this was expensive to build"

[@AlbertaGeek]

In Schlock Mercenary there's the spingrav Credomar habitat.

[@OwnerOfOwn]

Just binged all of your videos, you are awesome! keep up the amazing content man. Also you pronouncing ecumenopolis and shouting out isaac arthur was hilarious.

[@cheesesentience]

I love this video, and I love your inclusion of Project Hail Mary and Rama, but why didn't you include Hermes from The Martian?

[@OverviewEffekt]

It just didn't make the cut... :-(

[@hayshed]

Very neat renders and great explanations!

[@lizgutierrez5498]

Where are the O'Neill cylinders, like from Gundam? I figured those would be pretty big? If it's too realistic, it's also used in many of the Gundam Series, so it's also sci-fi enough, I think.

[@kilemeinocalvire9898]

so haven's river (last thing mentioned) is actually consisting of millions (trillions?) of O'Neil cylinders all linked together to create the massive larger structure basically think of the O'Neil cylinders as beads on a string i very much recommend reading (or listening ) to the bobbiverse series

[@johnpaulvanson5170]

Rama is an O'Neill Cylinder and what brought that variation of the Oberth cylinder from the 1930s to the west's attention at least. (Similar were shown in sci-fi and futurism books from the Warsaw Pact nations years before Clarke and O'Neill published anything on them). So's Cooper Station, for that matter.

[@adsilcott]

My favorite are the orbitals. A lot of sci-fi structures that big feel like they're going for the wow factor, but in the context of The Culture, the orbitals just seem like the most logical construction for a post-scarcity society that needs homes for trillions of beings. The fact that those people get to design the landscapes and live on big luxurious parcels of land if they want to just adds to the advanced future vibe. All of these were great picks to include in this list -- great video!

[@jiggermole]

Id probably add birch world as the grand pappy of them all

[@cola98765]

Was looking for someone mentioning Birch world A sphere around SMBH... it is BIG.

[@fiiral5870]

Birch World doesnt spin for gravity, it uses the SMBH at its center for gravity as a shellworld

[@cola98765]

@@fiiral5870 true, but would not be that out of place here

[@jiggermole]

@fiiral5870 you are correct, I retract my recommendation. Then a recommendation for a future vid. Habitable megastructure scale maybe?

[@tsiehta13]

Thank you for including the Topopolis. Its great to get a visual after listening to the book series. The bobiverse is fantastic.

[@harriehausenman8623]

🤗

[@DarthRust]

I love a nice hot cup a scrith in the morning.

[@jackemled_but_gay]

The UN & The Patriarchy want to know how you managed to liquify that stuff!

[@cat_city2009]

No mention of The Citadel from Mass Effect?

[@hotfightinghistory9224]

I had a dream where I was standing inside Heavens River.... it was beyond awesome :)

[@harriehausenman8623]

I had that too. And then I was back in my matrix.

[@simmeseins6845]

"Don't say warhammer" You got me with these words. Got to follow your channel now❤

[@GrandVizierPestage]

Per the ending I find myself obligated to recommend Warhammer to you

[@s33rlies4]

It should be noted that there is a way to have such a large tangental velocity, via the reverse of a orbital ring. Have a non rotating ring which is magneticly supporing the rotating ring.

[@DarthRust]

I also suppose that Bolder's Ring from Stephen Baxter's Xeelee Sqeuence deserves an honorable mention. It was 2 million (or more) light years across and had a tangential velocity very near the speed of light in order to open up a naked Kerr Metric in the center. The reasons why is another story...

[@jacobopstad5483]

Does tangential velocity really matter though if the acceleration is still only 1 g?

[@LegendLength]

10:18 absolute nerds

[@Madjedi7]

I love that he included Heaven's River. The Bobiverse series is amazing, I cannot wait for the next book.

[@DrLynch2009]

The Ringworld is unstable!

[@Akio-fy7ep]

So are skinny cylinders like Rama and Bab5. They want to tumble end-over-end, and will at slightest provocation.

[@oblivion_2852]

The movie Stowaway also uses a cable spin method of increasing the diameter without making it unreasonably expensive in terms of materials. The crew board whats called a cycler that has an orbit that periodically moves between earth and mars that ships can rendezvous with. Basically once the cycler is created no extra fuel is needed to increase or decrease the velocity. There's also a scene in the movie that shows how a tether based system spins up

[@unkn0wngu4rd1an]

sooo.... what's with the Citadel from Mass Effect? you listed a model in the discription but there is nothing in the video about it...

[@KyleWoodlock]

Tangential velocity isn't actually a problem at all? Linear velocity produces no strain whatsoever on a structure. It would be a challenge to dock on the outer surface, but that's why you'd build your docking infrastructure at the center (or at the poles in the case of a sphere) to minimize the tangential velocity there.

[@dingdong1456]

I love your channel and hope for more videos next year :D

[@77Fmydog]

bro your community is thriving! 700 comments the day of release! with only 70k subs. thats an insane conversion rate! im your newest sub btw :P

[@alexbstl]

Bolder’s Ring from the Xeelee sequence would be a fun comparison just for the insanity

[@zh84]

In "Xeelee Redemption" we have a ringworld 10,000 astronomical units in circumference, rotating with a tangential velocity near lightspeed. The idea is that by coming aboard you can make time slow down to an arbitrarily low level and wait out catastrophic events in safety.

[@Espartanica]

Halo is a ring because it's a weapon first, and a sanctuary second. It builds up energy in the middle of the ring for a while before firing, sending more energy into the accumulated mass from points all around the circumference. IRL wise, it looks cool, of course, but that's the in-lore explanation

[@mamadoubah3143]

wow, that helped a lot to visualise all my favourite books better, thank you

[@jake.l.m]

yessss i love that you included heavens river. such an awesome book too

[@lewismassie]

Great to see them all in one place. It is kinda funny that the scales are fairly reasonable, get pretty large, then jump way way up into the crazy land. Oh and by the way, if you're wanting to calculate how much tension force a spinning ring puts out on it's material, the thing you're gonna want to look up is Hoop Stress/Hoop Strain/Cylinder Stress. Took me a good few months to figure that exact phrasing out

[@billynomates6602]

Been wondering about this for ages. I'm so happy that the first exploration I've come accoss, yours, is so good. I loved your clear and awe inspiring graphics. I see one comment below in which the commentaror describes how delighted they were that serious reflection on you exposition wasn't already buried in guff. I hope to catch your work again before some idiot calls you a Fascist.

[@Oceiros95]

im glad i found this video- the level of attitude through this was refreshing lmao

[@CaptainMobius0]

Good to see Heaven's River made an appearance! I had pictured it in my head, but it's nice to see it on screen!

[@fracturedkoi1]

I quite love the level of detail “Heaven’s River” goes in to when describing the titular station. It’s by far my favorite book of the series to date.

[@MrHannatas]

Cool to see topopolis visualized, i somehow thought it was much smaller than this, great ro see it compared like that!

[@DerSolinski]

Heavens River FTW! Thank you for including it. It's my favorite book of the series, there is so much going on. If you like space opera try Backyard Starship, and for some more emphasis on the Fi try the Black Ocean: Galaxy Outlaws series.

[@jordanwhite9627]

Really enjoy your channel, some of my favorite videos on hard sci-fi. I have a suggest for a video on hard sci-fi of the SevenEves book. The use of the ISS in the story along with the generational space station in the later half of the book are very interesting.

[@OverviewEffekt]

I'll check it out!

[@delphicdescant]

"don't say warhammer" Thank you, truly.

[@schrodingersjet1043]

One idea you could add in a future video would be a circular ribbon tilted at about a 45 degree angle. I mean, the entire loop would not be tilted but the top part of the ribbon has a greater diameter than the bottom part of the ribbon, like a circular track for racing bicycles or motorcycles on earth. I use the terms top and bottom because such a structure wouldn't be useful in space, it would be useful on our moon. The idea is to take advantage of the natural gravity the moon provides but increase it by spinning a ring that's at an angle like the slope on a racetrack. I honestly think such spinning rings will be built on our moon in 2 or 3 centuries when we find that the 1/6th gravity there leads to health problems.