If I'm not completely misreading how shellworlds work, nothing is stopping you from doing both terrestrial and aquatic mega-habitats on the exact same structure. Just alternate the layers. Thin terrestrial shell over a hydroshell, or below it, or both.
Um, I think that might actually be doable, nice one. I think I need to play with that a bit but if I do make it work we'll have to call it an Eyjolfsson 'something' since matrioshka shellworld is already taken :) It's sort of like a layer cake.
An ocean over the top of a shell world seems like it would make for pretty effective protection against both radiation and most kinetic impacts too, plus you don't need to patch any holes in the ocean and if you're pumping up the ecology with artificial lighting and such you could probably produce a whole lot of food out of your "armor".
@@isaacarthurSFIA Well, that's certainly not on my list of "things I expect to see first thing I wake up in the morning. Still have to digest this. Give me a few days...or years... 😯
@@isaacarthurSFIA I'd love to brainstorm a good name for it, but I'm not entirely comfortable putting my name on it. Besides, everyone's just going to butcher the pronunciation anyways - they always do, even here in Sweden. Icelandic name, deceptively hard to pronounce.
The Hydroshell idea seems to have more potential beyond a marine habitat. Build it big enough and the necessary mass would create an escape velocity fast enough to hold an atmosphere despite the low surface gravity. The low surface gravity would then result in a very tall air column within which a human could strap wings to their arms and fly even easier than on Titan, maybe even swim in the air if we are talking hundredths of a g as discussed in the video. Furthermore, the active support necessary for the interior shell could, at least in part, be adapted into rotating ring habitats illuminated by an artificial sun at the center. These rotating habitats would be far larger than anything materials could support as they would not depend on tensile strength but the weight of the water and atmosphere outside to keep them from flying apart. The interior ring habitats could provide 1 g areas in an otherwise very low gravity structure as well as a place for a terrestrial ecosystem. They could even allow a deep ocean under 1 g since tensile strength and therefore the weight of water would not be an issue.
Assuming there are accessible access tunnels between the surface, ocean, and inner support rings, the inner rotating rings could serve as a form of rapid but risky transportation across large distances. Very good setting to put an adventure story.
@@paperburn far more than JUST an engineering problem. A problem that encompasses almost all our current problems and adds a whole slew of additional problems lol.
I dunno. Building it big enough also increases diameter and therefore reducing surface gravity. Initially you'd think the thickness of the shell increasing would counter that issue...bit that brings up entirely new issues
I love the idea of a boiling "sun" at the center of one of these, a book centered around the exploits of some intelligent species that was introduced into a hydroshell could be incredibly creative with speculative biology ecology and culture
Considering that Europa has no atmosphere and any lifeform that are speculated to live there live in an ocean under ice I wonder if it's possible to create an aquatic space habitat that simply has an ice shell and water core. If you provide just enough heat at the center of the ice sphere you can have a sea of water yet still have an icy shell that can be coated with some thin coating to prevent sublimation of ice. This can be a concept for cheap space farming habitats
@Peter from NZ I'm too lazy to do the math, I just know that it's possible because if you see that kind of structure formed naturally and possibly a common sight in space it shouldn't be hard to recreate it. The problem is ice have poor tensile strength you might have to embedd some fiber into it otherwise it will break apart from the centrifugal force. I don't think waiting will be a problem as this kind of structures are pretty much molded you can have millions of them serving as water storage as a secondary purpose.
@@capturedflame People making fun of it until they realise that pykrete is an ablative shield that will dissipate any blaster shooting at it and since the whole station is a massive heatsink, there won't be an exhaust port for the rebels to shoot at and even if it does, the thermal signature won't be high enough for their weapons to lock on.
The ice surface would be slowly sublimating to vapor and floating away if there isn't enough mass and gravity to maintain an atmosphere. It would need some kind of stable surface coating to keep it from slowly evaporating away to nothing.
@@operator8014 You can go one step further by just fill water into a flexible mold coated with thin layer of metal and transparent window only on where you need sunlight for the algea and fishes you are farming
Just thinking about the uplifted Octopuses from Children of Ruin and their massive spherical water filled space ships and stations. Wonderful book. Yet another wonderful video Isaac.
Just looked it up. Brain spiders sounds cool. What kind of spiders were they? Were they giant, heavily modified spiders or were they just like a colony of regular sized orb weavers.
@@logangrimnar3800 The spiders are Portid jumping spiders that were on the planet when the uplift virus meant for monkeys landed on the planet. Tiny little spiders.
I can also totally see a Civil War between humanist and trans-humanist. The transhumanists would see the humanists as backwards, science-denying, supremacists who hate improvement. While the humanists would see the trans as elite power-hungry technocrats who would use their asymmetric control of biology and tech to control everyone else they see as "lesser". If you had a virus that could modify people that much, and you were a technocrat, why wouldn't you just use it to bring your definition of "peace". Just rewire your oppositions brain to not care about frivolous issues anymore, like self determination, dignity and independence?
As an old time viewer who loves futurism and fishing I really loved this episode, I can only imagine what a fishing trip to a super earth ocean would be like. Keep the good work Isaac
I am hard of hearing, but you have a very clear speaking voice. I am aware you have a mild speech impediment but you have clearly put a lot of effort into overcoming it. Just thought I would let you know you have nailed it.
I always wondered about the concept of space habitats for our aquatic life. Shallow water creatures would be easiest since we already do it with aquariums but sea life such as dealing with some creatures that require larger open waters like whales and sharks and some that need higher pressures to thrive.
Great video Isaac! Just want to point out that a similar megastructure to what's described here was the setting of a book called Serpent Mage, the fourth book of the Death Gate Cycle from Margaret Weis and Tracy Hickman. It featured an aquatic shell world, complete with a freely drifting sea-star and floating islands that followed the star's route through the sea. It's a high fantasy series, though, with the world being made by wizards and the "islands" actually being enormous sea creatures. Still a good read, though!
I feel the problem with your bridge analysis compared to a spinning habitat is that a bridge has to carry not part, but ALL its cabling and pillars under 1 g. A spinning habitat only needs to carry the floor of the habitat at 1 g, and all the suspension cabling (or structural support) will only need to resist the weight of the habitat at 1g, (as with the bridge) but itself at progressively less g the closer to the center. Its kinda like you get a large part of the structural support's weight being carried for free. Also a spinning habitat has the benefit of (hopefully) being a closed circle, providing extra support through resistance to tensile strength of the floor itself. It would therefore be FAR EASIER to carry the floor of a spinning habitat for 1 g, then it would a suspension bridge. Probably to the point that if you design it well, it could carry double if not triple the gravity for the same kind of material a bridge can.
In one of his early videos on habitats, he showed the math for bridges and the habitats and it is the same math. Physics sometimes is very counterintuitive
The spinning speed of habitat could be lowered to emulate less than 1g at floor. This would make living there more pleasant and lessens the pressure on the structure.
The problem with relying on its circular shape for strength is that there would be a positive feedback loop for any ovalation. If parts of the circle move further from the centre, they experience a greater force so move further and so on. Eventually the circle would collapse into a flat line.
Great episode. Low-gravity super-oceans, yeeessss! Assuming a sufficiently dense food chain, what would the 'natural' size limits even be for ginormous leviathans in such environments?
A shell world with a shallow sea and tons of islands would be all kinds of interesting. A mega-scale planetary archipelago! All with plenty of space below the surface for gas storage, or tucking away a black hole for safe keeping / mass / etc.
I'm thinking of an slightly lovecraftian world, where bubbles of breathable air+rock islands float inside a dark ocean inhabited by whales and giant squid.
Finally!!!! I been wanting to here a good take on the challenges of habitats under extreme pressure. Sounds so much harder to withstand than those in a vacuum. I gotta go get some snacks.
I love your 'hydroshell' concept! and yes, I believe this is the first place I've ever heard that concept articulated. Leave it to Isaac Arthur to figure out how to make excellent colony worlds for our fine aquatic friends!
I would have liked a bit of a nod to tidal forces and free surface effects. If you spin up a bottle of water in zero g any displacement of mass to one side shifts the center of mass and rotation and makes the far side "downhill" and the system self balances. If you do the same with an O'neil cylinder you are likely to pull it out of round and now you've lost the self regulating aspect. You also face bending like a bow )|( . On the ocean shell world the rigid hollow sphere is subject to buoyant forces so without a series of bulkheads to separate out the water into discrete compartments what starts out as a tidal bulge would shift the center of mass of the whole structure and collect all of the water, floating that rigid shell partially out of the side.
In my top 5 favorite channels on youtube. I truely appreciate this. I hope this channel never experiences a book burning, or a loss. These ideas are to be studied, pondered upon, and applied even in our modern times. Have you ever considered organizing a few different programs with multiple videos.. & burning them to DVDs, & sending them out to different institutes? Such as schools, writers guild, directors etc. (Or doing so digitally & emailing with an adequate & eyecatching title) It wouldn't be overly expensive & I think doing so over a few years we could see a huge spike in these ideas being propagated & potentially sparking a surge of inspiration in young creative &/or scientific minds.
Space is an Ocean: SFIA-style. This is going to be wild. Come on, where's the reference to the Ouster's river among the stars in _Hyperion_ ? You know he's going to do it.
How would you keep the water from evaporating away into space on a hydroshell? Obviously you could build an outer shell or have an extremely strong magnetic field that keeps the molecules close. It would just be interesting to see what the options were on the low gravity versions since a certain amount of pressure is required to keep water in a liquid form at all.
Good thoughts. Issac Author suggests a glassy sphere, a layer of atmosphere, and a metal sphere in episode. But you could also use float glassy boubles. Or let the water start to evaporate, freeze and protect the water below. Dealing with water is easier then air
My designs are hexagonal, with three habitat and maintenance curls, three environmental/farming curls per round, with spinning providing faux gravity within the scythe-shaped spokes. Rotation and wobble provide day/night cycles. The rounds can be stacked, spaced apart by a central hub, including having side spokes holding other rounds, such that all of their rotations support the overall cycles of the entire structure.
To those asking/complaining about retaining atmosphere: For a hydroshell with a surface gravity of g and a radius R, the escape velocity is sqrt(2 * g * R). (This is actually the same as for a regular planet.) You want the escape velocity >~ 10 km/s to keep an Earth-like atmosphere at the surface. Low surface gravity can be compensated by a large size. Should be doable. If you have enough light+greenhouse gases + internal power generation you can keep the temperature up enough to have liquid water at the surface without having to worry over much about evaporation. Magnetic fields are only relevant if you are fighting solar wind which, if you're building a hydroshell, you have probably engineered away anyway.
I've been doing various calculations all week. In the most recent round I've included non-uniform gravity in the sub-shell stress (elastostatics) and ocean pressure (hydrostatics) calculations. I've also included a simple isothermal atmosphere. I've only done a non-rotating hydroshell. Adding rotation would be a neat way to get different ocean depths and maybe even land at the poles, but it complicates things significantly. As the orbital period of these things is so long, you probably want to keep any rotational period much longer than a day and achieve your day/night cycles another way. You could achieve seasons and climate cycles using rotation and an orbit with axial tilt, but a natural 24 hour day/night cycle is probably pushing it structurally. I've done all the calculations assuming everything is much thinner than the hydroshell radius, but with no assumptions about the relative thicknesses of shell, ocean and atmosphere, beyond assuming the applicability of linear elasticity and a constant density equation of state for ocean and sub-shell. The only additional assumption is that the ocean and shell mass is much greater than the atmospheric mass. This means I can ignore the atmosphere's self-gravity in computing its density/pressure profile (otherwise it involves numerically integrating Poisson's equation which I don't feel like). I have calculated a static equilibrium, but not examined stability. I make no guarantees that it won't buckle and collapse! Here is an example of what is possible with "real" materials. A 600 km thick diamond shell could support a 10 km deep water ocean and a breathable air atmosphere at 1 atm of pressure at 300 Kelvin with an escape velocity of 10 km/s. The ocean surface and ocean bottom gravity are approximately equal at 0.18 gee. The atmospheric scale height is 47 km and the ocean bottom pressure is 175 atm. The hydroshell radius is 4.4 Earth radii with a surface area of just under 20 Earth surface areas. The shell mass is 3.52 Earths (~2*10^25 kg), the ocean is 0.02 Earths (10^23 kg), and the atmosphere is approximately negligible (~ 6*10^20 kg), for a total mass of 3.54 Earths. The sub-shell compressive stress is ~ 670 MPa, which is a good 20x less than the compressive yield strength of diamond. You could maybe build bigger, but the prospect is scary. I would imagine the desired safety margins on a project like this are even bigger than I've allowed. Just out of interest I also calculated some orbital parameters. "Low earth orbit", which I define as an altitude of 20 * the atmospheric scale height, is ~ 7 km/s with a period of 7 hours. "Lunar orbit", defined as an orbit radius 60 * the body radius is at 1 km/s with a period of 135 days. A total of 4.6*10^18 W of power generation/capture are required to keep the structure heated. If you want to build bigger you want your unobtainium structural shell to have a lower mass density, higher compressive yield strength, and a lower or even negative Poisson ratio. That let's you make the shell thicker and hence stronger for no cost of extra gravity.
I think the Hydroshell has some merit (and came up in a Star Trek episode) but I think you would want to up the gravity and stick in an atmosphere on the outside. Water will boil away as the pressure drops so the water exposed to vacuum will be constantly lost.
Which Trek episode? The only I can think of that one with Tom Paris in Voyager where he got demoted ad that was a planetoid made of water all the way through. Is that the one you're thinking of or did I miss one?
The great thing about an episode like this is that it shows where we could end up if we pointed ourselves in the right direction, today. Us humans. Us custodians of the living things of (so far) the known Universe. It's the right kind of answer to people who object to Space exploration on the basis that Earth should come first. Firstly, no, you mean Life should come first. We need to treat Life as the most precious (most valuable - even in dollar terms) thing we have some kind of possession over. And in the very long term that means we still need to learn how to become truly ambitious - ambitious enough to save and propagate Life (so that if there wasn't panspermia before, once we're done, there will be.) It's about what we Will do, right now, more than about what we Can do. (It helps to have some ideas of how we could make it possible, though). What we Will do, in the simplest terms, means "In what direction should we point our feet today?" And here's a very good case in favour of saying, "We need to head thataway. There's a destiny that could lead us to a good kind of greatness. There's a fine purpose for us to work toward." And then we point our feet more or less thataway today. Which means we don't perfectly align ourselves toward what a less ambitious approach would have suggested. Those of us who are presidents of countries, for instance, would become less focused on grabbing a few square feet of Earth, now, for some "Mesopotamian" reason - learned from the people of long ago - who had very little ambition, or narrow ambitions. It's more important to do everything possible to redirect as much as makes sense (given our current level of civilization) from pursuits like collecting green pieces of paper that don't feel happy, or fenced acres, to things like getting out there, taking advantage of the first advantages that confers, and then going beyond that, all the way. To true ambition's ends.
Regarding water-filled spin habitats. If you wanted deep ecology, and weren't trying to create all the ecologies above it, can you not simply pressurize it? Regarding floating "stars" in a sea,. If you don't do SOMETHING to prevent life from encircling it, life will eventually encyst it. I'd recommend periodically "pulsing" the sun brighter to boil off anything that tried to hold on too closely, causing the current shell to break away, frequently enough to encourage non-encysting life to thrive as well as, or better than, the encysting life.
Totally cool. Conceived this for my Ceres setting a few years back when I wrote the crap draft for my sequel novel. Eventually I'll get them all out. This is a perfect design proof of concept. Thank you, @Isaac
Awesome concepts, beautiful art, and amazing sound. Well done Isaac and team! Now on to Space Marine Legion Habitats for those still loyal to the Emperor, hahaha.
I'm happy to see some charts in this episode. I felt nostalgic for the early days of this channel and it prompted a thought: Is it possible to remake some of the earliest episodes? I'm thinking that the episodes can remain mostly the same, except in those places where Isaac wants an update. The main advantage would be to give the old content the smooth voice of the modern Isaac Arthur. This would make some of those foundational episodes more accessible to a wider audience.
Many have actually been remade, almost all the first year's episode either got a redo or expanded into a series, I just have a rule about only doing it if there's a good amount of new content. I am completing redoing the original megastructure episode-0 vid, but that's for a mix of presentation to the national space society and episode for June and might be a really long one.
A very provocative episode. I hope to have time to watch again, take notes, explore the questions I have, chase down the possibilities cantilevering off this idea .... methinks this means the episode is a success :D
Something I haven't heard discussed is the logistics of transporting all that water to the hab in the first place. I know we can handwave the shell world scale stuff because there's already an insane level of logistics to get a planet-sized amount of mass somewhere. But if you're talking about stuff at the o'neill scale, I'm not sure which is more cost effective: space elevatoring it up from earth's gravity well, or grabbing a comet from the oort cloud that's big enough to fill the entire cylinder. Maybe pull hydrogen and oxygen from lunar regolith, and fire it with the mass driver to where the cylinder is? I mean, you'd have a similar problem shipping atmosphere up to a cylinder as well, but the mass of that is significantly less than a 100% water hab. And I have to imagine that a Kardishev 1.5 civilization would involve a lot more air-filled habs than water-filled habs, so there's a lot less economy of scale happening to make the process cheaper.
Set up your habitat in orbit of a hydrogen rich gas giant. Robots scoop up hydrogen, combust with oxygen to create water, heat, and light. Oxygen produced in nuclear reactors. You now have plenty of heat, light, and electrical power. Its a matter of scale as to efficiency.
"Easiest" way would be to either divert a comet composed of suitable volatiles to wherever you want it or Mine out blocks of ice from said comet or a moon and deliver them by mass driver. I'd think that using something as expensive as a space elevator for volatile shipping seems less economically viable to me than mining the outer system instead, relying on smaller craft and catapults (assuming theres already a solid space industry)
Space elevators are trash & aren't even competative for relatively small kiloton payloads let alone the gigatons it would take to build any of the megastructure habs. Now an orbital ring might give asteroids/comets a run for their money in the inner system & they eventually become ur only option since the belts have only a few percent of the moon's mass meaning you can't build too much hab space before you run out. Eventually you just start pulling hydrogen off gas giants & using it to process metal ores giving you all the water you could possibly need
@@virutech32 A space elevator on Titan - got your water, dueterium / tritium fuel, nitrogen for your atmosphere, and shallower gravity well. (without having to chase and retrieve comets)
About the hydroshell, as it has a huge surface area and a (relatively) low mass, I'd imagine that meteoritic fall would add a significant mass very quickly
Out of curiosity, if a train was travelling inside an oneil cylinder in a direction opposite and a speed matching the spin, would the occupants experience micro gravity?
@@hosmerhomeboy That would make for interesting speeding tickets for drivers. Imagine losing traction because you were speeding the wrong direction and managed to end up in micrograv.
@@paperburn Why rethink the frames of reference? If a passenger is traveling in a train and the track is a closed loop with a train on the inside of the loop, then increasing one’s speed would increase the centrifugal force experienced. “Simulated gravity” is just centrifugal force experienced inside a closed surface. What are we missing?
A lot of deep ocean creatures also don't need that pressure for their survival. Deep sea squids are notoriously hard to keep in captivity even as larvae, to the point where Giant Squids have never been kept, but keeping their tank at crushing pressures is not one of the requirements.
About spinning and gravity it reminded of an experiment of water with debris in it spun in microgravity. The debris went to the surface and water in the middle. The video also spoke on hollow earth theory too of planet spinning for the dirt to go around the outside(surface). I don’t believe in that but interesting idea.
Most spacestead habitats would include at least a few small bodies of water. But to have all ocean and no dry land is an entirely different concept altogether! On the nature preserve side of things, all kinds of ecosystems could be replicated in these giant space stations. Rainforests, savannahs, deserts, tundras, lagoons, etc.
Marine Habitat with Chandler Cities on the inside connected to a spaceport on the outside, could even have a vacuum train connecting the mid level of the chandelier cities, Look at the Earth 2.0 series, Colinizing the Oceans for Chandelier cities to see how this would function
I think making an O'Neil cylinder that instead of being really long, slowly wraps around to form a donut would be interesting for marine life. Unlike terrestrial life that mostly stays in one location of their entire lives, most marine animals migrate a lot. So having it possible to keep going in one direction and be able to get back to their original starting place should be interesting.
How would cavitation bubbles behave in such a lower pressure and lower gravity environment? Could you realistically swim fast enough to move but not too fast to rip the skin off your bones with cavitation bubbles? Or would cavitation bubbles simply deal less damage as a result of these lower pressures/gravity?
see the phase diagram for water and consider that the bubbles form when the pressure is bellow the boiling pressure at a given temperature, that means that with lower overall pressure the bubbles would probably implode slower and make them do less damage
Run the water down to the core where you have Nuclear reactors which you can use to not only heat the water, produce electric and some minerals but also super heated water which can be used as the active support materials for sustaining the structure. All self contained, outlets could simulate hydrothermal vents while also maintaining ocean currents and likely weather on the surface.
Engineer the reactors so intense radiation doesn't stray outward and kill any life you want nearby. Do that then engineer it so said life doesn't accidentally cause problems for the machinery and you have a very cool setup.
@@mill2712 Nuclear reactors as the stand are cooled with sea water with zero radiation transfer and given the sizes we are dealing with i doubt it will be much of an issue with life as it only poses minor issues as it is and they pull directly from the ocean a few meters away.
One thing I have wondered about for a while, concerning these super structures in space, is the maintenance over longer ranges of time. Over a millennia or so, if knowledge of the technology needed for the long term upkeep is lost, noone even remember that their world is manmade, or you just get incompetent/negligent people in power who just think in short terms (unimaginable, right), how do you prevent a human made structure floating in space from becoming a death trap?
Great episode. I always thought water ice would make a great construction material for a hull, have a thin foil cylinder with a multi-layered sun shield (a la JWST's sun shield) to cool the surface , spin it up just enough to get started and give you the gravity needed to keep water from sublimation, heat the water, spray it on the inside of the foil let it freeze, then when it's at the desired thickness, which maybe hundreds of meters,, put a slightly salty ocean on top (as on the inside up, ie: towards the centre of spin), as ice is buoyant in salty water, this will actually create a pre-tension in the hull towards the centre and increase the hull strength, allowing you to put down your land mass etc, floating islands etc before you spin it up more to get the desired gravity. Other advantages are that water-ice as a hull is self repairing, small impacts just melt the ice which fills in the crater and freezes, of course some repair of the sun-shield maybe needed, or perhaps you could use a water emulsion with highly reflective particles on the outside surface, to make it difficult to melt in raw sun light, or some other passive technology to keep it solid. As you stated water is so common and easy to use, you could make these things huge. I could even imagine water-ice hulls so massive then have their own gravity on both sides.
If a good design for water-based is long not deep... question, how does an entity inside a ball of water feel a sudden change of direction/sudden acceleration? Say, 20g? Thinking about certain long asteroids accused of being mother ships and certain UFOs who somehow keep their occupants alive and seem to really, really prefer water.
For the deep sea fishes we could just have a normal o neil cylinders with a normal volume of water just spinning at a higher rpm to simulate higher gravity consequently higher pressure and we could just use low power lights to simulate the darkness of the depths
Could you talk on a video or on a pair to how you predict our level of technological advancement we will have in 10, 20, 30, 40k years ? As somewhat of a mention from Warhammer 40k and it's Dark Age of Technology
That was a bad ass design for a space habitat! Blocks radiation, allows for fish, cooling for the computers etc, storage for gases and building materials inside the sphere.
You should make a zero gravity habitat video, like giant bubbles with land and water and air and inside, the weather patterns or other phenomena inside these would be completely alien to use
Hi Isaac. Sugesting you Sojourn series (some parts here on youtube, especially ship types). Inspired by expanse series, nexus, the jupiter incident electronic game, etc. Verry interesting especially regarding the gravity onboard.
Speaking of topopolis, a book called heaven's river from a series called the Bobiverse has a semi aquatic Alien river species that built a topopolis they called Heaven's River, which has a massive two way river system running through the entire length of the topopolis.
My math is a tad rusty to calculate it myself but in principle you can fill one of these with gas, like hydrogen and use the pressure to support the structure, would increase the gravity at the bottom but not by much and then you don't even need active support, just a shell to keep the water above the gas
Like number 198 and comment 41; have you ever though about doing an interview with Dr Neil Tyson on star for talk? I'm sure there are many things y'all could definitely talk about that would be awesome to watch and listen to.
Hmm, reminds of that episode from Voyager where they came across an artificially created "ocean planet" which was nothing but water held together by a device generating gravity at its center.
The future tourist attraction I want to visit is the zero-g habitat containing a giant ball of water held together only by surface tension, that I can slip into an swim around inside of with colorful fish. Yeah, I know fishies don't do well in zero-g, but if we let enough species give it a try, something will adapt.
Arcording to my calculus, the escape velocity of the shell described at 20:30 would be 6.6km/s That's roughly half the escape velocity of the earth and means (as I understand) that water would escape faster. But that's only a problem with solar wind comparable to what we know on earth
Question: How much water, just water would it take to create 1g? How big would this hydoshpere be -at least bigger than 34 Earths right? It would naturaly form a sphere and would proably create ice by pressure at it's core. So we don't have to build a mega-structure it would mostly occure without materials, other than water, and therorically with less engineering this could be one of humanitys first artifical planets. We could have power-sats around it to create a magnetic field with an orbital ring to help keep the atomos/hydrosphere intact. Every million years or so or whatever it takes we control drop a comet in to this mega-ocean to replace what water and atmosphere that we would lose through sun/star shine and what we would use in fusion. We could have a megalopolis floating or submarinar. Little to no genetic engineering. We could have areas for preserves and others to grow food. Thank you for another great and thought provoking video.
You know I always liked the idea of giant space oceans… but sadly its impossible since the water probally will froze out but its just made me wonder, can a giant mass of water can exist while orbiting a star? No, not a aquatic planet, I mean a literally water mass, a flying ocean where pressure increases as you swim into center of the ocean, “shallow” sea lifeforms exist in corners of the bubble while deep pressure lifeforms prefer center… I actualy in past got a idea for my scifi world where a spaceship crash create a space ocean and the aquatic lifeforms samples the ship carying is evolves to live in space ocean, tardigardes, planktons, algae, Ctenophora… and creatures like this.
there's no reason that an oceanic planet needs to freeze. It just needs to be warm enough & high pressure enough to not freeze. so as long as the planet is close enough to its star & has enough greenhouse gasses(much like early earth) it should stay liquid at the surface
Something you did not mention but might make shell worlds more interesting is you can fill them with atmosphere. The shell would enclose an aero world of zero gravity. .
Fish Farms. You can have the farms without the pollution such as fish poo run-offs that upsets the chemistry balance of local water ways. We're talking about a future where it's likely cheap to get things into orbit.
Love the vids! Been subscribed for a while. I keep wondering though - where is your accent from? Sounds very Boston to me but i could be completely wrong!
The reason folks on the ISS experience micro gravity is because they and the station are, in effect, falling together at the same rate. They are also going sidewise fast enough that they are missing the earth as they fall.
How much atmosphere outside of the water would a hydroshell design be able to hold onto long term? Example: 1 - Hydroshell world 2 - Water layer 3 - Atmosphere over the water This could be a great way to build a possibly habitable world, especially if the opposite of the Fermi Paradox is true. To whit, I mean, "There's no real estate left because either all the star systems to which we can gain easy access already have life, either by starting locally, or being colonized before we could get out to the stars."
One thing that's niggling at me with the shell worlds unique gravitational arrangement is what's preventing it from degrading to a traditional sphere and/or separating. My brain is just having trouble with the gravitational effects being focused at the surface level
I suppose a lot of these techniques could be used as a bridge for aquatic species to become space faring (assuming they get past fire). Their lift ships are just lift without much environment support. Robots build their ships, including the, comparatively, heavy environment, and they dock with them to do their baby-steps work. Might produce a culture that uses robots almost exclusively at first, but has a jump on orbital infrastructure building from it's "manned' exploration program.
4:43 You know also looking for this chart for a while, and i couldn't seem to find it. if you show a chart in the video could you place a copy into the description please?
One obvious point about artificial worlds is that they require maintenance. Which shows the biggest benefit of using whole natural worlds for building your habitats on: they won't fall apart if you neglect them. Nature preserves meant purely for the conservation of the various species that coexist in a given habitat/biome would be best served with an actual world. Humans can be expected to lose interest in any long-term regime of maintenance, eventually. However, if you want parks, or renewable resource habitats, where people can be expected to take daily interest in going there to play or work ... those you can build. The maintenance then becomes just another job that society is happy to pay someone to do. But "who cares about puffins and polar bears?" could someday become a catchphrase for people who no longer want to keep up their nature sanctuaries. As transport vessels, their expected duration is limited, even if the trip needs centuries, but "forever" is another story. That, I see, is the best reason for caring about preserving the Earth, and looking for new worlds to colonize. Worlds don't need maintenance just to remain intact as worlds. The life on them does require some stewardship, but we already have that issue, and we should be ready to shoulder that responsibility anyway. Engineered habitats need people, but nature preserves need worlds if we hope them to last for geological/astronomical spans of time. Hopefully, a good planet is not too hard to find.
Natural worlds are a terrible preserves since they're no where near stable. Plenets regularly kill off vast portions of their own ecologies & they're completely vulnerable to asteroid impacts. They're pretty shite if the objective is a indefinitely stable habitat. If you want a stable hab you make a superstructure hab & just automate it's maintenance. Just because something requires maintenance doesn't mean people have to be doing it. In fact id argue that for trully massive megastructures to even be practical you really need to have pretty extensive & advanced automation for both construction & maintenance. Once it's automated you can armour it up with hydrogen fuel tanks and run off that, stably, for trillions of years
Our universe isn't like you see in Sci-fi. Habitable planets to earth life might be much harder to find than what you might think and if you don't live in an FTL society (If FTL is possible which most likely it isn't.) it becomes much harder. Terraforming seems like a better idea but it takes A LOT of maintenance to successfully pull it off and it is not a permanent solution to just leave by itself. You have to maintain the planet you terraformed to keep it habitable otherwise it will revert back to where you found it.
@@mill2712 - FTL is probably possible. Newest research has detected "warp bubbles" at the atomic scale. If they do occur, at any scale, they might be amenable to artifice.
@@virutech32 - automated maintenance also needs maintenance. Geological eons are not proof against change under any circumstances. Creatures kept in a preserve will likely evolve anyway, if they last that long. Tens of millions of years is plenty long enough. Don't you agree? We might find lots of even better planets, or invent a maintenance free system before a backup planet gets pummelled by an asteroid.
If I'm not completely misreading how shellworlds work, nothing is stopping you from doing both terrestrial and aquatic mega-habitats on the exact same structure. Just alternate the layers. Thin terrestrial shell over a hydroshell, or below it, or both.
Um, I think that might actually be doable, nice one. I think I need to play with that a bit but if I do make it work we'll have to call it an Eyjolfsson 'something' since matrioshka shellworld is already taken :) It's sort of like a layer cake.
@@isaacarthurSFIA You're amazing!
An ocean over the top of a shell world seems like it would make for pretty effective protection against both radiation and most kinetic impacts too, plus you don't need to patch any holes in the ocean and if you're pumping up the ecology with artificial lighting and such you could probably produce a whole lot of food out of your "armor".
@@isaacarthurSFIA Well, that's certainly not on my list of "things I expect to see first thing I wake up in the morning. Still have to digest this. Give me a few days...or years... 😯
@@isaacarthurSFIA I'd love to brainstorm a good name for it, but I'm not entirely comfortable putting my name on it. Besides, everyone's just going to butcher the pronunciation anyways - they always do, even here in Sweden. Icelandic name, deceptively hard to pronounce.
The Hydroshell idea seems to have more potential beyond a marine habitat. Build it big enough and the necessary mass would create an escape velocity fast enough to hold an atmosphere despite the low surface gravity. The low surface gravity would then result in a very tall air column within which a human could strap wings to their arms and fly even easier than on Titan, maybe even swim in the air if we are talking hundredths of a g as discussed in the video. Furthermore, the active support necessary for the interior shell could, at least in part, be adapted into rotating ring habitats illuminated by an artificial sun at the center. These rotating habitats would be far larger than anything materials could support as they would not depend on tensile strength but the weight of the water and atmosphere outside to keep them from flying apart. The interior ring habitats could provide 1 g areas in an otherwise very low gravity structure as well as a place for a terrestrial ecosystem. They could even allow a deep ocean under 1 g since tensile strength and therefore the weight of water would not be an issue.
Assuming there are accessible access tunnels between the surface, ocean, and inner support rings, the inner rotating rings could serve as a form of rapid but risky transportation across large distances. Very good setting to put an adventure story.
@@remy5405 that is just an engineering problem, mount them elsewhere on the body
@@paperburn far more than JUST an engineering problem. A problem that encompasses almost all our current problems and adds a whole slew of additional problems lol.
I dunno. Building it big enough also increases diameter and therefore reducing surface gravity. Initially you'd think the thickness of the shell increasing would counter that issue...bit that brings up entirely new issues
I love the idea of a boiling "sun" at the center of one of these, a book centered around the exploits of some intelligent species that was introduced into a hydroshell could be incredibly creative with speculative biology ecology and culture
Considering that Europa has no atmosphere and any lifeform that are speculated to live there live in an ocean under ice I wonder if it's possible to create an aquatic space habitat that simply has an ice shell and water core. If you provide just enough heat at the center of the ice sphere you can have a sea of water yet still have an icy shell that can be coated with some thin coating to prevent sublimation of ice. This can be a concept for cheap space farming habitats
@Peter from NZ I'm too lazy to do the math, I just know that it's possible because if you see that kind of structure formed naturally and possibly a common sight in space it shouldn't be hard to recreate it. The problem is ice have poor tensile strength you might have to embedd some fiber into it otherwise it will break apart from the centrifugal force. I don't think waiting will be a problem as this kind of structures are pretty much molded you can have millions of them serving as water storage as a secondary purpose.
@@capturedflame People making fun of it until they realise that pykrete is an ablative shield that will dissipate any blaster shooting at it and since the whole station is a massive heatsink, there won't be an exhaust port for the rebels to shoot at and even if it does, the thermal signature won't be high enough for their weapons to lock on.
The ice surface would be slowly sublimating to vapor and floating away if there isn't enough mass and gravity to maintain an atmosphere. It would need some kind of stable surface coating to keep it from slowly evaporating away to nothing.
@@operator8014 You can go one step further by just fill water into a flexible mold coated with thin layer of metal and transparent window only on where you need sunlight for the algea and fishes you are farming
@@operator8014 Just paint it, problem solved
Just thinking about the uplifted Octopuses from Children of Ruin and their massive spherical water filled space ships and stations. Wonderful book.
Yet another wonderful video Isaac.
Let's go on an adventure.
Just looked it up. Brain spiders sounds cool. What kind of spiders were they? Were they giant, heavily modified spiders or were they just like a colony of regular sized orb weavers.
@@logangrimnar3800 The spiders are Portid jumping spiders that were on the planet when the uplift virus meant for monkeys landed on the planet. Tiny little spiders.
I can also totally see a Civil War between humanist and trans-humanist. The transhumanists would see the humanists as backwards, science-denying, supremacists who hate improvement. While the humanists would see the trans as elite power-hungry technocrats who would use their asymmetric control of biology and tech to control everyone else they see as "lesser".
If you had a virus that could modify people that much, and you were a technocrat, why wouldn't you just use it to bring your definition of "peace". Just rewire your oppositions brain to not care about frivolous issues anymore, like self determination, dignity and independence?
@@logangrimnar3800 The spiders grew over time, by the end of the book the roughly human intelligence spiders were around 3 feet wide or so.
As an old time viewer who loves futurism and fishing I really loved this episode, I can only imagine what a fishing trip to a super earth ocean would be like. Keep the good work Isaac
Fishes in Space!
Three of the upcoming topics are particularly exciting to me: Nuclear Transmutation, Synthetic Life and Moon: Mega City.
I am hard of hearing, but you have a very clear speaking voice. I am aware you have a mild speech impediment but you have clearly put a lot of effort into overcoming it. Just thought I would let you know you have nailed it.
I always wondered about the concept of space habitats for our aquatic life. Shallow water creatures would be easiest since we already do it with aquariums but sea life such as dealing with some creatures that require larger open waters like whales and sharks and some that need higher pressures to thrive.
If you need a high pressure habitat it would be easier to pressurize a container without all the mass.
Great video Isaac! Just want to point out that a similar megastructure to what's described here was the setting of a book called Serpent Mage, the fourth book of the Death Gate Cycle from Margaret Weis and Tracy Hickman. It featured an aquatic shell world, complete with a freely drifting sea-star and floating islands that followed the star's route through the sea. It's a high fantasy series, though, with the world being made by wizards and the "islands" actually being enormous sea creatures. Still a good read, though!
I feel the problem with your bridge analysis compared to a spinning habitat is that a bridge has to carry not part, but ALL its cabling and pillars under 1 g. A spinning habitat only needs to carry the floor of the habitat at 1 g, and all the suspension cabling (or structural support) will only need to resist the weight of the habitat at 1g, (as with the bridge) but itself at progressively less g the closer to the center. Its kinda like you get a large part of the structural support's weight being carried for free. Also a spinning habitat has the benefit of (hopefully) being a closed circle, providing extra support through resistance to tensile strength of the floor itself. It would therefore be FAR EASIER to carry the floor of a spinning habitat for 1 g, then it would a suspension bridge. Probably to the point that if you design it well, it could carry double if not triple the gravity for the same kind of material a bridge can.
Also farm soil would not be continuous and only cover individual roots. Water pools on opposite sides balance the the O Neill structure.
In one of his early videos on habitats, he showed the math for bridges and the habitats and it is the same math. Physics sometimes is very counterintuitive
The spinning speed of habitat could be lowered to emulate less than 1g at floor. This would make living there more pleasant and lessens the pressure on the structure.
The problem with relying on its circular shape for strength is that there would be a positive feedback loop for any ovalation. If parts of the circle move further from the centre, they experience a greater force so move further and so on. Eventually the circle would collapse into a flat line.
@@ChazCharlie1 Nope. This cylinder spins centerless. 1 gyro on each end and it's manouver able.
Great episode. Low-gravity super-oceans, yeeessss! Assuming a sufficiently dense food chain, what would the 'natural' size limits even be for ginormous leviathans in such environments?
We Love you from Jamaica 🇯🇲 ❤
I would love a video on amusement park space stations (literally I think only I would be interested 😂)
Very cool ideas. I like the way you think
A shell world with a shallow sea and tons of islands would be all kinds of interesting. A mega-scale planetary archipelago! All with plenty of space below the surface for gas storage, or tucking away a black hole for safe keeping / mass / etc.
I'm thinking of an slightly lovecraftian world, where bubbles of breathable air+rock islands float inside a dark ocean inhabited by whales and giant squid.
Finally!!!! I been wanting to here a good take on the challenges of habitats under extreme pressure. Sounds so much harder to withstand than those in a vacuum. I gotta go get some snacks.
I love your 'hydroshell' concept! and yes, I believe this is the first place I've ever heard that concept articulated. Leave it to Isaac Arthur to figure out how to make excellent colony worlds for our fine aquatic friends!
I would have liked a bit of a nod to tidal forces and free surface effects. If you spin up a bottle of water in zero g any displacement of mass to one side shifts the center of mass and rotation and makes the far side "downhill" and the system self balances. If you do the same with an O'neil cylinder you are likely to pull it out of round and now you've lost the self regulating aspect. You also face bending like a bow )|( .
On the ocean shell world the rigid hollow sphere is subject to buoyant forces so without a series of bulkheads to separate out the water into discrete compartments what starts out as a tidal bulge would shift the center of mass of the whole structure and collect all of the water, floating that rigid shell partially out of the side.
I appreciate your thinking about. I figured there'd have to be some kind of currents and stuff generated by the spin but didn't know which.
In my top 5 favorite channels on youtube. I truely appreciate this. I hope this channel never experiences a book burning, or a loss. These ideas are to be studied, pondered upon, and applied even in our modern times.
Have you ever considered organizing a few different programs with multiple videos.. & burning them to DVDs, & sending them out to different institutes? Such as schools, writers guild, directors etc. (Or doing so digitally & emailing with an adequate & eyecatching title) It wouldn't be overly expensive & I think doing so over a few years we could see a huge spike in these ideas being propagated & potentially sparking a surge of inspiration in young creative &/or scientific minds.
I would love to see what sort of life evolves in a deep but bright ocean.
(Any/all)
3:19 You spin me right round baby right round like a record baby right round round round!
Now I'm going to have Dead or Alive stuck in my head all day :)
@@isaacarthurSFIA you're welcome Isaac!
Space is an Ocean: SFIA-style. This is going to be wild.
Come on, where's the reference to the Ouster's river among the stars in _Hyperion_ ? You know he's going to do it.
How here for Outsters
There's a series I need to re-read, its been a while :)
How would you keep the water from evaporating away into space on a hydroshell? Obviously you could build an outer shell or have an extremely strong magnetic field that keeps the molecules close. It would just be interesting to see what the options were on the low gravity versions since a certain amount of pressure is required to keep water in a liquid form at all.
Good thoughts.
Issac Author suggests a glassy sphere, a layer of atmosphere, and a metal sphere in episode.
But you could also use float glassy boubles.
Or let the water start to evaporate, freeze and protect the water below.
Dealing with water is easier then air
My designs are hexagonal, with three habitat and maintenance curls, three environmental/farming curls per round, with spinning providing faux gravity within the scythe-shaped spokes. Rotation and wobble provide day/night cycles. The rounds can be stacked, spaced apart by a central hub, including having side spokes holding other rounds, such that all of their rotations support the overall cycles of the entire structure.
To those asking/complaining about retaining atmosphere: For a hydroshell with a surface gravity of g and a radius R, the escape velocity is sqrt(2 * g * R). (This is actually the same as for a regular planet.) You want the escape velocity >~ 10 km/s to keep an Earth-like atmosphere at the surface. Low surface gravity can be compensated by a large size. Should be doable.
If you have enough light+greenhouse gases + internal power generation you can keep the temperature up enough to have liquid water at the surface without having to worry over much about evaporation.
Magnetic fields are only relevant if you are fighting solar wind which, if you're building a hydroshell, you have probably engineered away anyway.
I've been doing various calculations all week. In the most recent round I've included non-uniform gravity in the sub-shell stress (elastostatics) and ocean pressure (hydrostatics) calculations. I've also included a simple isothermal atmosphere.
I've only done a non-rotating hydroshell. Adding rotation would be a neat way to get different ocean depths and maybe even land at the poles, but it complicates things significantly. As the orbital period of these things is so long, you probably want to keep any rotational period much longer than a day and achieve your day/night cycles another way. You could achieve seasons and climate cycles using rotation and an orbit with axial tilt, but a natural 24 hour day/night cycle is probably pushing it structurally.
I've done all the calculations assuming everything is much thinner than the hydroshell radius, but with no assumptions about the relative thicknesses of shell, ocean and atmosphere, beyond assuming the applicability of linear elasticity and a constant density equation of state for ocean and sub-shell. The only additional assumption is that the ocean and shell mass is much greater than the atmospheric mass. This means I can ignore the atmosphere's self-gravity in computing its density/pressure profile (otherwise it involves numerically integrating Poisson's equation which I don't feel like).
I have calculated a static equilibrium, but not examined stability. I make no guarantees that it won't buckle and collapse!
Here is an example of what is possible with "real" materials.
A 600 km thick diamond shell could support a 10 km deep water ocean and a breathable air atmosphere at 1 atm of pressure at 300 Kelvin with an escape velocity of 10 km/s.
The ocean surface and ocean bottom gravity are approximately equal at 0.18 gee. The atmospheric scale height is 47 km and the ocean bottom pressure is 175 atm.
The hydroshell radius is 4.4 Earth radii with a surface area of just under 20 Earth surface areas.
The shell mass is 3.52 Earths (~2*10^25 kg), the ocean is 0.02 Earths (10^23 kg), and the atmosphere is approximately negligible (~ 6*10^20 kg), for a total mass of 3.54 Earths.
The sub-shell compressive stress is ~ 670 MPa, which is a good 20x less than the compressive yield strength of diamond. You could maybe build bigger, but the prospect is scary. I would imagine the desired safety margins on a project like this are even bigger than I've allowed.
Just out of interest I also calculated some orbital parameters. "Low earth orbit", which I define as an altitude of 20 * the atmospheric scale height, is ~ 7 km/s with a period of 7 hours. "Lunar orbit", defined as an orbit radius 60 * the body radius is at 1 km/s with a period of 135 days.
A total of 4.6*10^18 W of power generation/capture are required to keep the structure heated.
If you want to build bigger you want your unobtainium structural shell to have a lower mass density, higher compressive yield strength, and a lower or even negative Poisson ratio. That let's you make the shell thicker and hence stronger for no cost of extra gravity.
I think the Hydroshell has some merit (and came up in a Star Trek episode) but I think you would want to up the gravity and stick in an atmosphere on the outside. Water will boil away as the pressure drops so the water exposed to vacuum will be constantly lost.
Which Trek episode? The only I can think of that one with Tom Paris in Voyager where he got demoted ad that was a planetoid made of water all the way through. Is that the one you're thinking of or did I miss one?
The great thing about an episode like this is that it shows where we could end up if we pointed ourselves in the right direction, today. Us humans. Us custodians of the living things of (so far) the known Universe. It's the right kind of answer to people who object to Space exploration on the basis that Earth should come first. Firstly, no, you mean Life should come first. We need to treat Life as the most precious (most valuable - even in dollar terms) thing we have some kind of possession over. And in the very long term that means we still need to learn how to become truly ambitious - ambitious enough to save and propagate Life (so that if there wasn't panspermia before, once we're done, there will be.)
It's about what we Will do, right now, more than about what we Can do. (It helps to have some ideas of how we could make it possible, though). What we Will do, in the simplest terms, means "In what direction should we point our feet today?"
And here's a very good case in favour of saying, "We need to head thataway. There's a destiny that could lead us to a good kind of greatness. There's a fine purpose for us to work toward."
And then we point our feet more or less thataway today.
Which means we don't perfectly align ourselves toward what a less ambitious approach would have suggested. Those of us who are presidents of countries, for instance, would become less focused on grabbing a few square feet of Earth, now, for some "Mesopotamian" reason - learned from the people of long ago - who had very little ambition, or narrow ambitions. It's more important to do everything possible to redirect as much as makes sense (given our current level of civilization) from pursuits like collecting green pieces of paper that don't feel happy, or fenced acres, to things like getting out there, taking advantage of the first advantages that confers, and then going beyond that, all the way. To true ambition's ends.
This is so cool :) great episode. I hope we do build these someday!
Oceans in space? Well, let's dive in!
Im disappointed that I laughed from this
@@Haphast Well I guess the punchline came out... swimmingly.
On my walk to Uni! A good day for learning
Regarding water-filled spin habitats. If you wanted deep ecology, and weren't trying to create all the ecologies above it, can you not simply pressurize it?
Regarding floating "stars" in a sea,. If you don't do SOMETHING to prevent life from encircling it, life will eventually encyst it. I'd recommend periodically "pulsing" the sun brighter to boil off anything that tried to hold on too closely, causing the current shell to break away, frequently enough to encourage non-encysting life to thrive as well as, or better than, the encysting life.
Same with the vents. Let them overpressurize and erupt occasionally.
Totally cool. Conceived this for my Ceres setting a few years back when I wrote the crap draft for my sequel novel. Eventually I'll get them all out. This is a perfect design proof of concept. Thank you, @Isaac
the idea with the submarine dome on an ocean habitat is awesome, I wanna live there now!
Awesome concepts, beautiful art, and amazing sound. Well done Isaac and team! Now on to Space Marine Legion Habitats for those still loyal to the Emperor, hahaha.
I'm happy to see some charts in this episode. I felt nostalgic for the early days of this channel and it prompted a thought:
Is it possible to remake some of the earliest episodes?
I'm thinking that the episodes can remain mostly the same, except in those places where Isaac wants an update. The main advantage would be to give the old content the smooth voice of the modern Isaac Arthur. This would make some of those foundational episodes more accessible to a wider audience.
Many have actually been remade, almost all the first year's episode either got a redo or expanded into a series, I just have a rule about only doing it if there's a good amount of new content. I am completing redoing the original megastructure episode-0 vid, but that's for a mix of presentation to the national space society and episode for June and might be a really long one.
A very provocative episode. I hope to have time to watch again, take notes, explore the questions I have, chase down the possibilities cantilevering off this idea .... methinks this means the episode is a success :D
Something I haven't heard discussed is the logistics of transporting all that water to the hab in the first place. I know we can handwave the shell world scale stuff because there's already an insane level of logistics to get a planet-sized amount of mass somewhere. But if you're talking about stuff at the o'neill scale, I'm not sure which is more cost effective: space elevatoring it up from earth's gravity well, or grabbing a comet from the oort cloud that's big enough to fill the entire cylinder. Maybe pull hydrogen and oxygen from lunar regolith, and fire it with the mass driver to where the cylinder is? I mean, you'd have a similar problem shipping atmosphere up to a cylinder as well, but the mass of that is significantly less than a 100% water hab. And I have to imagine that a Kardishev 1.5 civilization would involve a lot more air-filled habs than water-filled habs, so there's a lot less economy of scale happening to make the process cheaper.
Set up your habitat in orbit of a hydrogen rich gas giant. Robots scoop up hydrogen, combust with oxygen to create water, heat, and light. Oxygen produced in nuclear reactors. You now have plenty of heat, light, and electrical power. Its a matter of scale as to efficiency.
"Easiest" way would be to either divert a comet composed of suitable volatiles to wherever you want it or Mine out blocks of ice from said comet or a moon and deliver them by mass driver. I'd think that using something as expensive as a space elevator for volatile shipping seems less economically viable to me than mining the outer system instead, relying on smaller craft and catapults (assuming theres already a solid space industry)
Space elevators are trash & aren't even competative for relatively small kiloton payloads let alone the gigatons it would take to build any of the megastructure habs. Now an orbital ring might give asteroids/comets a run for their money in the inner system & they eventually become ur only option since the belts have only a few percent of the moon's mass meaning you can't build too much hab space before you run out.
Eventually you just start pulling hydrogen off gas giants & using it to process metal ores giving you all the water you could possibly need
Why go nearly a LY out instead of visiting the icy moons of Jupiter and Saturn?
@@virutech32 A space elevator on Titan - got your water, dueterium / tritium fuel, nitrogen for your atmosphere, and shallower gravity well. (without having to chase and retrieve comets)
OhMyGoodness 😃 The March line-up looks positively cosmic! 🙏🏽🌌🚀
About the hydroshell, as it has a huge surface area and a (relatively) low mass, I'd imagine that meteoritic fall would add a significant mass very quickly
NEW MEGASTRUCTURE! WOO HOO! Ya love to see it.
The best part of Thursday: another vid from this guy
This was the focus of one episode of Star Trek Voyager. I am so happy to see Isaac Arthur bring this up here. :D
I remember that mostly as the one Tom Paris got demoted in. :)
Really good episode, Always worth to have some Space related stuff on TH-cam.
ian banks "matter
depicts a rope water world. its amazing. i hope we create things like that one day.
Out of curiosity, if a train was travelling inside an oneil cylinder in a direction opposite and a speed matching the spin, would the occupants experience micro gravity?
they'd have to. and the converse would be true as well, going with the spin would increase the apparent gravity.
Yes. Would be fun ride.
@@hosmerhomeboy you need to rethink your frames of reference
@@hosmerhomeboy That would make for interesting speeding tickets for drivers. Imagine losing traction because you were speeding the wrong direction and managed to end up in micrograv.
@@paperburn Why rethink the frames of reference? If a passenger is traveling in a train and the track is a closed loop with a train on the inside of the loop, then increasing one’s speed would increase the centrifugal force experienced. “Simulated gravity” is just centrifugal force experienced inside a closed surface. What are we missing?
Where on Earth is the amazing landscape shown at 21:50? I want to go there!
Reine, Norway
my first impression was Brasil, but once the camera rises it looks more like the Norwegian fiords
Love your info , also one of my favorite cartoons """ Clarence"" you sound exactly like him. i freaking LOVE,LOVE it
An interesting aspect of life in a space-can would be that microgravity and activities that can be done in it is always just overhead
A lot of deep ocean creatures also don't need that pressure for their survival. Deep sea squids are notoriously hard to keep in captivity even as larvae, to the point where Giant Squids have never been kept, but keeping their tank at crushing pressures is not one of the requirements.
About spinning and gravity it reminded of an experiment of water with debris in it spun in microgravity. The debris went to the surface and water in the middle. The video also spoke on hollow earth theory too of planet spinning for the dirt to go around the outside(surface).
I don’t believe in that but interesting idea.
Any day when I learn of a new megastructure is a good day.
The more I learn, the more I learn how much I don't know.
Most spacestead habitats would include at least a few small bodies of water. But to have all ocean and no dry land is an entirely different concept altogether!
On the nature preserve side of things, all kinds of ecosystems could be replicated in these giant space stations. Rainforests, savannahs, deserts, tundras, lagoons, etc.
Marine Habitat with Chandler Cities on the inside connected to a spaceport on the outside, could even have a vacuum train connecting the mid level of the chandelier cities, Look at the Earth 2.0 series, Colinizing the Oceans for Chandelier cities to see how this would function
I think making an O'Neil cylinder that instead of being really long, slowly wraps around to form a donut would be interesting for marine life. Unlike terrestrial life that mostly stays in one location of their entire lives, most marine animals migrate a lot. So having it possible to keep going in one direction and be able to get back to their original starting place should be interesting.
Ive long considered this topic. Thank you for the excellent presentation.
How would cavitation bubbles behave in such a lower pressure and lower gravity environment?
Could you realistically swim fast enough to move but not too fast to rip the skin off your bones with cavitation bubbles?
Or would cavitation bubbles simply deal less damage as a result of these lower pressures/gravity?
see the phase diagram for water and consider that the bubbles form when the pressure is bellow the boiling pressure at a given temperature, that means that with lower overall pressure the bubbles would probably implode slower and make them do less damage
Run the water down to the core where you have Nuclear reactors which you can use to not only heat the water, produce electric and some minerals but also super heated water which can be used as the active support materials for sustaining the structure. All self contained, outlets could simulate hydrothermal vents while also maintaining ocean currents and likely weather on the surface.
Best part would be the inside could be human habitable with the ocean acting as a very nice shield for Radiation and Meteors.
Engineer the reactors so intense radiation doesn't stray outward and kill any life you want nearby. Do that then engineer it so said life doesn't accidentally cause problems for the machinery and you have a very cool setup.
@@mill2712 Nuclear reactors as the stand are cooled with sea water with zero radiation transfer and given the sizes we are dealing with i doubt it will be much of an issue with life as it only poses minor issues as it is and they pull directly from the ocean a few meters away.
Bye and thanks for all the fish!
One thing I have wondered about for a while, concerning these super structures in space, is the maintenance over longer ranges of time. Over a millennia or so, if knowledge of the technology needed for the long term upkeep is lost, noone even remember that their world is manmade, or you just get incompetent/negligent people in power who just think in short terms (unimaginable, right), how do you prevent a human made structure floating in space from becoming a death trap?
Great episode. I always thought water ice would make a great construction material for a hull, have a thin foil cylinder with a multi-layered sun shield (a la JWST's sun shield) to cool the surface , spin it up just enough to get started and give you the gravity needed to keep water from sublimation, heat the water, spray it on the inside of the foil let it freeze, then when it's at the desired thickness, which maybe hundreds of meters,, put a slightly salty ocean on top (as on the inside up, ie: towards the centre of spin), as ice is buoyant in salty water, this will actually create a pre-tension in the hull towards the centre and increase the hull strength, allowing you to put down your land mass etc, floating islands etc before you spin it up more to get the desired gravity.
Other advantages are that water-ice as a hull is self repairing, small impacts just melt the ice which fills in the crater and freezes, of course some repair of the sun-shield maybe needed, or perhaps you could use a water emulsion with highly reflective particles on the outside surface, to make it difficult to melt in raw sun light, or some other passive technology to keep it solid. As you stated water is so common and easy to use, you could make these things huge. I could even imagine water-ice hulls so massive then have their own gravity on both sides.
If a good design for water-based is long not deep... question, how does an entity inside a ball of water feel a sudden change of direction/sudden acceleration? Say, 20g?
Thinking about certain long asteroids accused of being mother ships and certain UFOs who somehow keep their occupants alive and seem to really, really prefer water.
For the deep sea fishes we could just have a normal o neil cylinders with a normal volume of water just spinning at a higher rpm to simulate higher gravity consequently higher pressure and we could just use low power lights to simulate the darkness of the depths
Was half-expecting to see you and Sarah as the mermaid and merman there for a second. (LOL) love your work!
You did one on my idea last week :) thank you.
I misread "space: marine" and got really excited about the Imperium of Man for a second there
:) I'd be tempted to do an episode on them some time too
another great episode, I want to watch this twice
My favorite episode in a long time!
Could you talk on a video or on a pair to how you predict our level of technological advancement we will have in 10, 20, 30, 40k years ?
As somewhat of a mention from Warhammer 40k and it's Dark Age of Technology
That was a bad ass design for a space habitat! Blocks radiation, allows for fish, cooling for the computers etc, storage for gases and building materials inside the sphere.
You should make a zero gravity habitat video, like giant bubbles with land and water and air and inside, the weather patterns or other phenomena inside these would be completely alien to use
This i think:
th-cam.com/video/BcJSz_q2bIk/w-d-xo.html
@@virutech32 Finally, a one sentence comment with a link that isn't a bot!
@@r3dp9 don't let me lull u into a false sense of security🤖
Neat. Now tell me about Space Marine habitats. Are they fortress monestaries or just UNSC super carriers?
Happy ArthursDay from Germany 😎🖖👍
What about colonizing phobos?
Hi Isaac. Sugesting you Sojourn series (some parts here on youtube, especially ship types). Inspired by expanse series, nexus, the jupiter incident electronic game, etc. Verry interesting especially regarding the gravity onboard.
Speaking of topopolis, a book called heaven's river from a series called the Bobiverse has a semi aquatic Alien river species that built a topopolis they called Heaven's River, which has a massive two way river system running through the entire length of the topopolis.
My math is a tad rusty to calculate it myself but in principle you can fill one of these with gas, like hydrogen and use the pressure to support the structure, would increase the gravity at the bottom but not by much and then you don't even need active support, just a shell to keep the water above the gas
Like number 198 and comment 41; have you ever though about doing an interview with Dr Neil Tyson on star for talk? I'm sure there are many things y'all could definitely talk about that would be awesome to watch and listen to.
Isaac wouldn't be able to get a word in.
@@stuart207 probably not with chuck and Neil does like to interrupt a lil bit lol
Hmm, reminds of that episode from Voyager where they came across an artificially created "ocean planet" which was nothing but water held together by a device generating gravity at its center.
I always smile as soon as I see this notification :)
The future tourist attraction I want to visit is the zero-g habitat containing a giant ball of water held together only by surface tension, that I can slip into an swim around inside of with colorful fish. Yeah, I know fishies don't do well in zero-g, but if we let enough species give it a try, something will adapt.
Arcording to my calculus, the escape velocity of the shell described at 20:30 would be 6.6km/s
That's roughly half the escape velocity of the earth and means (as I understand) that water would escape faster.
But that's only a problem with solar wind comparable to what we know on earth
I had a snack but not a drink. Fortunately, Isaac brought plenty of water!
Question: How much water, just water would it take to create 1g? How big would this hydoshpere be -at least bigger than 34 Earths right? It would naturaly form a sphere and would proably create ice by pressure at it's core. So we don't have to build a mega-structure it would mostly occure without materials, other than water, and therorically with less engineering this could be one of humanitys first artifical planets. We could have power-sats around it to create a magnetic field with an orbital ring to help keep the atomos/hydrosphere intact. Every million years or so or whatever it takes we control drop a comet in to this mega-ocean to replace what water and atmosphere that we would lose through sun/star shine and what we would use in fusion. We could have a megalopolis floating or submarinar. Little to no genetic engineering. We could have areas for preserves and others to grow food. Thank you for another great and thought provoking video.
You know I always liked the idea of giant space oceans… but sadly its impossible since the water probally will froze out but its just made me wonder, can a giant mass of water can exist while orbiting a star? No, not a aquatic planet, I mean a literally water mass, a flying ocean where pressure increases as you swim into center of the ocean, “shallow” sea lifeforms exist in corners of the bubble while deep pressure lifeforms prefer center… I actualy in past got a idea for my scifi world where a spaceship crash create a space ocean and the aquatic lifeforms samples the ship carying is evolves to live in space ocean, tardigardes, planktons, algae, Ctenophora… and creatures like this.
would it not just freeze?
there's no reason that an oceanic planet needs to freeze. It just needs to be warm enough & high pressure enough to not freeze. so as long as the planet is close enough to its star & has enough greenhouse gasses(much like early earth) it should stay liquid at the surface
Water is super unstable in vacuums, so it would just boil away.
Of course we have to consider the porpoises of an aquatic habitat. That's who's going to live there, after all.
Something you did not mention but might make shell worlds more interesting is you can fill them with atmosphere. The shell would enclose an aero world of zero gravity. .
Fish Farms. You can have the farms without the pollution such as fish poo run-offs that upsets the chemistry balance of local water ways. We're talking about a future where it's likely cheap to get things into orbit.
Love the vids! Been subscribed for a while.
I keep wondering though - where is your accent from? Sounds very Boston to me but i could be completely wrong!
You are such an amazing channel.
The reason folks on the ISS experience micro gravity is because they and the station are, in effect, falling together at the same rate. They are also going sidewise fast enough that they are missing the earth as they fall.
2:38 I had to look away until this part was over, because my eyes starting spinning too and I got sick.
How much atmosphere outside of the water would a hydroshell design be able to hold onto long term?
Example:
1 - Hydroshell world
2 - Water layer
3 - Atmosphere over the water
This could be a great way to build a possibly habitable world, especially if the opposite of the Fermi Paradox is true.
To whit, I mean, "There's no real estate left because either all the star systems to which we can gain easy access already have life, either by starting locally, or being colonized before we could get out to the stars."
Thanks Isaac!
One thing that's niggling at me with the shell worlds unique gravitational arrangement is what's preventing it from degrading to a traditional sphere and/or separating. My brain is just having trouble with the gravitational effects being focused at the surface level
I suppose a lot of these techniques could be used as a bridge for aquatic species to become space faring (assuming they get past fire). Their lift ships are just lift without much environment support. Robots build their ships, including the, comparatively, heavy environment, and they dock with them to do their baby-steps work. Might produce a culture that uses robots almost exclusively at first, but has a jump on orbital infrastructure building from it's "manned' exploration program.
Stellaris: Aquatics is released and now this, coincidence? I think not!
4:43 You know also looking for this chart for a while, and i couldn't seem to find it. if you show a chart in the video could you place a copy into the description please?
He probably made the chart himself, or it might be one on the discord.
One obvious point about artificial worlds is that they require maintenance. Which shows the biggest benefit of using whole natural worlds for building your habitats on: they won't fall apart if you neglect them.
Nature preserves meant purely for the conservation of the various species that coexist in a given habitat/biome would be best served with an actual world. Humans can be expected to lose interest in any long-term regime of maintenance, eventually. However, if you want parks, or renewable resource habitats, where people can be expected to take daily interest in going there to play or work ... those you can build. The maintenance then becomes just another job that society is happy to pay someone to do. But "who cares about puffins and polar bears?" could someday become a catchphrase for people who no longer want to keep up their nature sanctuaries. As transport vessels, their expected duration is limited, even if the trip needs centuries, but "forever" is another story.
That, I see, is the best reason for caring about preserving the Earth, and looking for new worlds to colonize. Worlds don't need maintenance just to remain intact as worlds. The life on them does require some stewardship, but we already have that issue, and we should be ready to shoulder that responsibility anyway. Engineered habitats need people, but nature preserves need worlds if we hope them to last for geological/astronomical spans of time. Hopefully, a good planet is not too hard to find.
Many really good points here. Thanks.
Natural worlds are a terrible preserves since they're no where near stable. Plenets regularly kill off vast portions of their own ecologies & they're completely vulnerable to asteroid impacts. They're pretty shite if the objective is a indefinitely stable habitat.
If you want a stable hab you make a superstructure hab & just automate it's maintenance. Just because something requires maintenance doesn't mean people have to be doing it. In fact id argue that for trully massive megastructures to even be practical you really need to have pretty extensive & advanced automation for both construction & maintenance. Once it's automated you can armour it up with hydrogen fuel tanks and run off that, stably, for trillions of years
Our universe isn't like you see in Sci-fi. Habitable planets to earth life might be much harder to find than what you might think and if you don't live in an FTL society (If FTL is possible which most likely it isn't.) it becomes much harder.
Terraforming seems like a better idea but it takes A LOT of maintenance to successfully pull it off and it is not a permanent solution to just leave by itself. You have to maintain the planet you terraformed to keep it habitable otherwise it will revert back to where you found it.
@@mill2712 - FTL is probably possible. Newest research has detected "warp bubbles" at the atomic scale. If they do occur, at any scale, they might be amenable to artifice.
@@virutech32 - automated maintenance also needs maintenance. Geological eons are not proof against change under any circumstances. Creatures kept in a preserve will likely evolve anyway, if they last that long. Tens of millions of years is plenty long enough. Don't you agree? We might find lots of even better planets, or invent a maintenance free system before a backup planet gets pummelled by an asteroid.