# How does everyone see life onboard an O'Neill cylinder?



## DAgent (Jun 27, 2022)

So I've been looking into using the idea of an O'Neil cylinder space station as a setting as I find the idea of such a place quite fascinating. I do have a few thoughts about things I've not quite been able to find out from any online sources, so I'd like to pick everyone else's brains a little. Anyone wanting an overview on these, please check out the wikipedia article: O'Neill cylinder - Wikipedia

Just how would the seasons work? Would it just be one long Spring and Summer for each "year"? or would they throw in Autumn and maybe a token Winter if they had total control over the weather cycle?

If they have some natural countryside settings, trees hedges, forests, and lets face it, I think we would all need those settings for recreation as well as cleaning the air and making oxygen and so on, would they also make use of traditional farming methods? If they did, would they be able to have several harvests a "year"? I'd imagine there would be hydroponic gardens as well.

Assuming they are using external solar panels on the hull to get energy from the sun, would there be any point in adding solar panels to any rooftops inside the habitat area? Or wind turbines, hydro electric generators in rivers, heat sinks in the ground and other uses of renewable energy?

Does anyone else have any thoughts about them that they can't find answers for?


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## Wayne Mack (Jun 27, 2022)

Some of the things I've always wondered:

Would it be possible to transit between the two cylinders due to opposite rotation or would the two communities become isolated?
How would a ship dock with the rotating station?
I assume that some sort of motor would be needed to maintain rotation. Otherwise, Friction between the two cylinders would cause slowing.
Where will material for new construction come from? Is it assumed that the buildings present on day one would last forever?


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## Venusian Broon (Jun 27, 2022)

Some material from Isaac Arthur.











I don't know if it answers your questions, but I'd guess they might be there.

He has a series on megastructures with 29  videos, with ringworlds, 'Continent-sized Rotating Space Habitats', Matrioshka brains, orbital rings etc.... that discusses related topics - look it up on his playlists.


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## Venusian Broon (Jun 27, 2022)

Wayne Mack said:


> Some of the things I've always wondered:
> 
> Where will material for new construction come from? Is it assumed that the buildings present on day one would last forever?





DAgent said:


> Just how would the seasons work? Would it just be one long Spring and Summer for each "year"? or would they throw in Autumn and maybe a token Winter if they had total control over the weather cycle?
> 
> If they have some natural countryside settings, trees hedges, forests, and lets face it, I think we would all need those settings for recreation as well as cleaning the air and making oxygen and so on, would they also make use of traditional farming methods? If they did, would they be able to have several harvests a "year"? I'd imagine there would be hydroponic gardens as well.
> 
> Assuming they are using external solar panels on the hull to get energy from the sun, would there be any point in adding solar panels to any rooftops inside the habitat area? Or wind turbines, hydro electric generators in rivers, heat sinks in the ground and other uses of renewable energy?


The way I see it, all of your questions are really only pertinent for the first O'Neil cylinders (if they get built). Where we don't really know too much and haven't had much practice at building them. If we really "conquer space" I think we could be on the way to making a Dyson swarm with billions of O'Neil cylinders and many other megastructures, depending on what we need the space for. And at that point, I think anything goes - why not have a 'winter' habitat with tundra ecologies all the time. And some with a 'natural' cycle of seasons. 

With regards to power, I think we'll need fusion - remember we could put the cylinder anywhere, and if we're going to make billions and trillions of them there's loads of space much further out where the sun's solar energy will not be enough to really power anything. But the ones closer to the sun could use more solar cells. 

Of course we'll need a lot of material for all these, and there a number of ways I'd think we'll get it. 

1) At first we could mine asteroids - plenty of companies and space agencies today are starting to think about this. 
2) We could convert the mass of the bigger objects of our system into useful stuff. I mean, do we really need Jupiter? This is much further off - although Moon mining might make sense. 
3) Finally we could uplift material from the sun directly and just use that. It's where all the mass of the solar system is (I believe there's about two Earth masses of gold somewhere in there. for example) Sure it'll mostly be hydrogen, but if we really master fusion, not only will we get energy, but potentially we could convert all this sun hydrogen into oxygen, carbon, iron etc. that we could then use as building materials. Yes, this now a bit far future, but it's theoretically reasonable! (Whereas at the moment, trying to build an interstellar ship that could get you to another star in under a human lifetime is less so.)


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## Astro Pen (Jun 27, 2022)

We already live on what one might call an 'O'Neill sphere' and it is a big bu**er. It is also largely self regulating and it will run for hundreds of millions of years.
Given the impossibility of interstellar cylinders, primarily due to energy supply. We are limited to the inner solar system. 

Even if we think we _can_ play god well enough to manage an artificial eco system why on earth would we build them? 
The only reason I can think of is as a semi permanent and multi generational colony of teraformers doing over Mars or Venus. 

However, sociologically, I watch the world today and I honestly think the hyper-modernist squeaky clean lifestyle such a colony requires is not viable. It is a delusion a very long way from real human variation and behaviour.

Life on the terraformer stations would likely have the character and crew mentality of a gulf oil rig rather than some being  perfect proto community of spandex clad utopians in a flying Eden. 
Just look at Johannesburg, Amsterdam, New York, Delhi. The rich, complex and varied way 99.9% of the world lives it's lives and you begin to see the reality check in the sci fi dream.
Would any one really want to live for decades on the very limiting environment  of a giant USS Enterprise? No way Jose. I'd go space crazy.  Give me the delicious and ever changing cultural smorgasbord down here any day.


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## psikeyhackr (Jun 27, 2022)

You will have to pay an air tax.


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## DAgent (Jun 28, 2022)

Venusian Broon said:


> Some material from Isaac Arthur.
> 
> 
> 
> ...


I'll have to give them a watch, what I've found online already does answer a lot of questions, but there's always just the odd one or two or five more that can come up after musing on things awhile longer


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## DAgent (Jun 28, 2022)

Astro Pen said:


> We already live on what one might call an 'O'Neill sphere' and it is a big bu**er. It is also largely self regulating and it will run for hundreds of millions of years.
> Given the impossibility of interstellar cylinders, primarily due to energy supply. We are limited to the inner solar system.
> 
> Even if we think we _can_ play god well enough to manage an artificial eco system why on earth would we build them?
> ...


What makes you think they are impossible? Certainly by today's standards they are, but if we get to a technology level where we can mine the moon and the asteroid belts, and refine those materials and use zero gravity engineering methods, we'd be at the point of development to make these sort of objects.

Though I have to admit, the thought of what would happen to the people on board these is another very interesting pointer. Would they end up going through the same sort of social issues we've gone through up to today? Would they be in a better position then we are now? Or, god forbid, a worse place as a society then we've ever been in recorded history?

Someone made a video on youtube showing what the inside of an O'Neill cylinder might look like, using New York City as a reference, including the twin towers. If you could physically make a cylinder that can hold a recreation of NYC, you can conceivable have enough space for quite a large chunk of humanity to live, complete with all kinds of plant life, which I think would be needed for so many reasons, including keeping the residents sane, as well as breathing.


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## DAgent (Jun 28, 2022)

psikeyhackr said:


> You will have to pay an air tax.


Yeah, I can see that happening. Even with a rain forest onboard.

That said, that does bring up the point of what kind of work would be done there? I can imagine all the money paid would be digital, or whatever replaces the thing that will eventually replace whatever replaces digital money transfers, rather then using paper money and coins. But what would everyone be doing for a living?

If there's traditional farming going on, there might very well be hydroponic gardeners as well, both earning their livings and paying their taxes, which means there would have to be bankers and tax collectors, maybe? Or would those last two roles be completely computer controlled?

Another thought that just cropped up in my head, would there be break away collectives of people on board after a couple of generations of live on the cylinder? Would someone try to setup their own hippy commune in the forest trying to get stoned on mushrooms, even though none of the magical variations were brought on board?


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## Wayne Mack (Jun 28, 2022)

DAgent said:


> if we get to a technology level where we can mine the moon and the asteroid belts, and refine those materials and use zero gravity engineering methods, we'd be at the point of development to make these [extraterrestrial habitats].


This presents a significant chicken and egg problem. To build an O'Neil Cylinder or similar ecosystem that supports human life without relying on Earth resources, extraterrestrial resources are needed. To mine or obtain these resources requires that there are extraterrestrial ecosystems that support human life. The first step needs to rely on resources from Earth and the result must provide benefit back to Earth. There is a limit to much can be done by relying on governments or rich individuals to pay for these things.

For the considerable future, efforts will need to remain small scale and need to justify resource needs based on benefit provided to Earth. I see the two potential benefits to be, moving 'dirty' industries off-planet and providing alternate sources for scarce or exhausted planetary resources.


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## Robert Zwilling (Jun 28, 2022)

Forgetting abut all the stuff whether it is viable or not, the main problem I found was how exactly does stuff including ships dock and transport goods and people get into a rotating station. I never did find any video that actually showed this happening. I found that simply saying they docked or by cutting off the video image just before the ship "lands" is the most practical way of doing it.

After talking with a friend, we came up with the idea that putting a track on the outside of the station that traveled in the opposite direction of rotation would provide a stable landing platform. Then the docking platform could move to a airlock on the outside of the station and entry was made that way. No idea what happened while making move from ship to station, just said entry was made, assumed gravity would be working.

An alternative method was to have the station rotating around a hollow tube axel. The axel was stationary compared to the movement of the ring. Then an airlock moving on a track, and then locked into position was used to get inside.


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## Wayne Mack (Jun 28, 2022)

The way I approached docking with a rotating space station was by having a large platform on the outer edge. A ship would land in a somewhat similar manner as a jet on and aircraft carrier. The ship would approach at a velocity slightly higher than the tangential velocity. The landing platform would rise up to meet the spaceship and centrifugal force would press the ship down onto the landing pad and convert its forward velocity into rotational speed. This also avoids any need to fire any rocket engines near the station to stop momentum.

I've gone back and forth on launch from the station on either having a cable give the spaceship a slight jerk forward or backward off of the landing strip. momentum would then throw the ship away from the station without needing to fire rocket engines in the vicinity of the station.


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## Astro Pen (Jun 28, 2022)

Go in the end using little thrusters to match rotation _a la_ 2001 docking
(Oh god how I _love_ that movie even half a century on.)


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## Orcadian (Jun 28, 2022)

I have never heard of an O'Neill cylinder spaceship and am enjoying reading and thinking about it for the first time. At the moment I'm not clear why you need a counter-rotating module. I rather thought you would orient your craft's rotation axis in any desired direction by transferring angular momentum to and from flywheels, much as with the ISS. But as I said, this is a new area for me...


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## Orcadian (Jun 28, 2022)

Astro Pen said:


> Go in the end using little thrusters to match rotation _a la_ 2001 docking
> (Oh god how I _love_ that movie even half a century on.)


That docking sequence is my favourite part of the film! Poetry in motion.


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## psikeyhackr (Jun 29, 2022)

Robert Heinlein wrote a short story, It's Great to be Back, about a colony on the Moon. A consequence of this was everyone had to be relatively smart. The astronauts of the Mercury Program all had IQs of at least 130.

Would you want to live with dumb people in space?  How easy would it be to cause deadly emergencies? 

So how would a society with only exceptionally smart people work?


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## Orcadian (Jun 29, 2022)

psikeyhackr said:


> Robert Heinlein wrote a short story, It's Great to be Back, about a colony on the Moon. A consequence of this was everyone had to be relatively smart. The astronauts of the Mercury Program all had IQs of at least 130.
> Would you want to live with dumb people in space?  How easy would it be to cause deadly emergencies?
> So how would a society with only exceptionally smart people work?


Well, if you had only 'smart people' there would still be a distribution of intelligence, with a mean and sigma. And you'd just define 'dumb' as being those who were >2 sigma below that mean.  (Same argument applies to 'poverty', incidentally.)


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## psikeyhackr (Jun 29, 2022)

Orcadian said:


> Well, if you had only 'smart people' there would still be a distribution of intelligence, with a mean and sigma. And you'd just define 'dumb' as being those who were >2 sigma below that mean.  (Same argument applies to 'poverty', incidentally.)


Simply saying "still have a distribution" does not mean the resulting society would not be significantly different from any society that has existed on Earth.

Comparing it to poverty is even more nonsensical. Do you think grammar school dropouts are going to be sent into space?


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## Swank (Jun 29, 2022)

Orcadian said:


> Well, if you had only 'smart people' there would still be a distribution of intelligence, with a mean and sigma. And you'd just define 'dumb' as being those who were >2 sigma below that mean.  (Same argument applies to 'poverty', incidentally.)


Most things don't require above average intelligence to learn and do. Smart people only really shine in complex situations or when attempting to produce a breakthrough in some field. So a city of relatively smart people would largely look like ours but with less crime and anger.




DAgent said:


> Just how would the seasons work?


Any way you want. Just as there are places on earth with only one season, you can design it to have 1 or however many you want per year. And that could be done by limiting the amount of time sunlight shines in, either via filters or altered day/night times. But the cylinder isn't big enough to have a climate, so your spring is still going to require artificial rain, for instance.



DAgent said:


> Assuming they are using external solar panels on the hull to get energy from the sun, would there be any point in adding solar panels to any rooftops inside the habitat area? Or wind turbines, hydro electric generators in rivers, heat sinks in the ground and other uses of renewable energy?


Nope. No wind for wind for turbines, no snowy mountains for rivers and solar panels on house roofs would be inefficient compared to those in vacuum, and you might not have house roofs at all. Why build houses when the hole world is built from scratch and the environment is controlled? Live under the plants, or in fabric structures. The whole place could be bikini temps year round with precisely controlled rain.



Wayne Mack said:


> How would a ship dock with the rotating station?


Aside from the hubs, another easy way to dock would be to fly at the edge of the rotating side, perpendicular to the axis. If the ship is traveling the same velocity as the outer circumference of the station, they will have a moment when they are static to hook up. At that point the station "lifts" the ship off of it's straight path and into the rotation - like a car tire tread grabbing a stone off a road. Launching would send the ship on its way with the velocity it arrived with - but in other directions. The advantage would be that the ship is under gravity while it is docked (which is also the disadvantage.    Ooop - looks like you answered your own question. But it is best think about the ship flying under the cylinder and being picked up rather than over and coming down.

Otherwise, you could just park near one end and come aboard through an inflatable tube. You don't have to hard dock.



Astro Pen said:


> Even if we think we _can_ play god well enough to manage an artificial eco system why on earth would we build them?


Why wouldn't you build them? Why would it be better to travel long distances and put up with all the downsides of a dead planet when a space station can have a perfectly controlled earth-type environment parked right near home? No blight, no mosquitos, no hurricanes. Low cost to travel between them and other vacuum locales. Plus, it doesn't destroy the natural environment of other planets and moons that aren't the right gravity or chemistry for earth life. After awhile, it would seem foolish to live on planets - like being a hunter/gatherer instead of working 9-5 and having a grocery store.



DAgent said:


> That said, that does bring up the point of what kind of work would be done there?


What kind of work do we do here? Do you know anyone who farms or builds machines? Most of us do things that are far removed from survival type activities. People in space will design shopping webpages, make porn, invest in bitcoin, run blood drives and operate liquor stores. Just like here.

But they may also do work building more orbiting stuff, maintaining powerstations that beam energy down to earth, make consumer goods out of space materials and then drop them to earth.




Orcadian said:


> I have never heard of an O'Neill cylinder spaceship and am enjoying reading and thinking about it for the first time. At the moment I'm not clear why you need a counter-rotating module. I rather thought you would orient your craft's rotation axis in any desired direction by transferring angular momentum to and from flywheels, much as with the ISS. But as I said, this is a new area for me...


You could. But the other cylinder _is_ the flywheel. Why build an dead flywheel of solid matter when you could have more living space?


Space stations could be great ways to put people in healthy environments and let the earth heal below. Consumption in space isn't nearly as awful as on a living planet with strong gravity. And if you decide that you want to go study saturn, you don't have to start all over with ships and construction - just take the slow ride out by moving a station where you want it. Space travel doesn't need to be cramped and resource starved.


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## Orcadian (Jun 29, 2022)

psikeyhackr said:


> Comparing it to poverty is even more nonsensical.


The comparison to poverty is as follows. At the moment (in the UK) organisations say people are 'in poverty' if their family income is below 60% of the average income.  If you suddenly (impossibly!) double everyone's income, you will still have that group whose income is less than 60% of the average.


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## Orcadian (Jun 29, 2022)

To clarify the point about defining people to be dumb, poor, rich, bright, etc, here's a thing I heard on the  (UK) radio some years ago. Half of all heart surgeons are below average. Do you want one of these to operate on you? The point is: 1. ALL heart surgeons have the expertise needed to operate on you safely; 2. All measures of success are relative and multi-dimensional.


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## SilentRoamer (Jun 29, 2022)

Venusian Broon said:


> 2) We could convert the mass of the bigger objects of our system into useful stuff. I mean, do we really need Jupiter? This is much further off - although Moon mining might make sense.


 Yes we do really need Jupiter. I'm tired of your anti-Jovian rhetoric!


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## Venusian Broon (Jun 29, 2022)

SilentRoamer said:


> Yes we do really need Jupiter. I'm tired of your anti-Jovian rhetoric!



We of Venus prefer the beauty of Saturn


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## Wayne Mack (Jun 29, 2022)

psikeyhackr said:


> Do you think grammar school dropouts are going to be sent into space?


Consider the work needed for or likely to be offloaded to a space station: mining, factory work, farming, station maintenance, sewage treatment. Who would most likely to be attracted to uprooting themselves and moving to a foreign environment. Refugees, perhaps?

By necessity, I suggest that a space station would be dominated by work not requiring any sort of advanced degree.


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## psikeyhackr (Jun 29, 2022)

Orcadian said:


> The comparison to poverty is as follows. At the moment (in the UK) organisations say people are 'in poverty' if their family income is below 60% of the average income.  If you suddenly (impossibly!) double everyone's income, you will still have that group whose income is less than 60% of the average.


Increasing everyone's income would probably just increase prices. We are indoctrinated to think about economics in the Right Way. Did Adam Smith?

All warfare is based on deception! The losers are supposed to be kept ignorant and confused.  Adam Smith used the word 'education' 80 times in Wealth of Nations. Search WoN for "and account" and you will find he wrote "read, write, and account" multiple times times. Not "read, write, and arithmetic."

Considering that double entry accounting is 700 years old it is curious that economists do not suggest mandatory accounting in the schools with all of the worship of Adam Smith. Western countries could have done that since the 1950s and the dumb definition of poverty ignored. The socialists could have thought of that. The job of economists is to rationalize the economic power game as Europeans have defined and evolved it.

Would people sent to live in space stations have average educations? The demands of the environment would enforce a new and unique culture. Maybe economists would not be smart enough to qualify.


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## psikeyhackr (Jun 29, 2022)

Venusian Broon said:


> We of Venus prefer the beauty of Saturn


Venusians think Saturn is cool?


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## DAgent (Jun 30, 2022)

Robert Zwilling said:


> Forgetting abut all the stuff whether it is viable or not, the main problem I found was how exactly does stuff including ships dock and transport goods and people get into a rotating station. I never did find any video that actually showed this happening. I found that simply saying they docked or by cutting off the video image just before the ship "lands" is the most practical way of doing it.
> 
> After talking with a friend, we came up with the idea that putting a track on the outside of the station that traveled in the opposite direction of rotation would provide a stable landing platform. Then the docking platform could move to a airlock on the outside of the station and entry was made that way. No idea what happened while making move from ship to station, just said entry was made, assumed gravity would be working.
> 
> An alternative method was to have the station rotating around a hollow tube axel. The axel was stationary compared to the movement of the ring. Then an airlock moving on a track, and then locked into position was used to get inside.


If you've ever seen Babylon 5 back in the 90's, which was based somewhat on an O'Neill design, their space station had two main ways for transport ships to dock. 

One was in what I'm going to refer to as "the spine" which ran along the top of the station and allowed the rest to rotate underneath it. At one end of "the spine" there was at least one docking bay area which was of course stationary and in theory easy to dock with. How anyone got to and from the rotating section to "the spine" is any ones guess of course.

Right underneath that was another docking bay entrance in the middle of the rotating section of the station. Visiting ships basically adjusted their course and speed and matched rotation, but I can't recall if we ever saw the complete docking process. I've looked but no one seems to have uploaded sequences like these onto YouTube, there are some fan recreations though.


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## DAgent (Jun 30, 2022)

Here's another thought that just came to mind. Would people living on the station notice the curvature of their "world" ? We don't really notice the Earths curvature, but on a cylinder the curvature is going the opposite direction. Would the residents notice this? Would there need to be a certain distance in the overall diameter to hide it? And how odd might it be to a visitor from Earth to see this, and likewise, if a Cylinder dweller visited Earth, would they find it off putting to not be able to see the rest of the "worlds" upwards curve?


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## DAgent (Jun 30, 2022)

Swank said:


> Most things don't require above average intelligence to learn and do. Smart people only really shine in complex situations or when attempting to produce a breakthrough in some field. So a city of relatively smart people would largely look like ours but with less crime and anger.
> 
> 
> 
> ...


I think if I was living on one of those, I would still want to live inside a somewhat traditionally built house with a roof. After all, it might help with things like solar panels which I somehow feel would end up being used to help absorb any internal light going inside the cylinder. But getting away and doing some "wild camping" would sound fun too.

I think if there is any working being done, it's probably going to be in specially made areas below the "land". I can somewhat picture there being "underground" offices, labs, repair bays, manufacturing plants and so on all being kept there to allow people to live in the more "natural" world above it, preferably in idyllic little villages, but probably in some sort of small city.


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## DAgent (Jun 30, 2022)

Orcadian said:


> To clarify the point about defining people to be dumb, poor, rich, bright, etc, here's a thing I heard on the  (UK) radio some years ago. Half of all heart surgeons are below average. Do you want one of these to operate on you? The point is: 1. ALL heart surgeons have the expertise needed to operate on you safely; 2. All measures of success are relative and multi-dimensional.


The idea that a heart surgeon who might be operating on me who might be less intelligent than me, would only be worrying if I actually knew what my own IQ was. I've only done online tests, and their results have been rather wildly different


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## psikeyhackr (Jun 30, 2022)

DAgent said:


> The idea that a heart surgeon who might be operating on me who might be less intelligent than me, would only be worrying if I actually knew what my own IQ was. I've only done online tests, and their results have been rather wildly different


The concept of IQ is at least 75% dumb it is just the only thing with a lot of statistical data.

How could all automobiles be evaluated with a single number ranging from 0 to 200? Different parts of IQ tests challenge different mental abilities, what sense does it make to mash them into a single number? But where is musical capability incorporated?

Who is going to "own/control" the cylinder and play gatekeeper?


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## Robert Zwilling (Jun 30, 2022)

DAgent said:


> Would people living on the station notice the curvature of their "world" ?


If there is an extended view overhead, I would think you could see the curvature of the other side of the ring as it stretched across the sky. To know for sure, one would need to calculate how big the other side of the ring would appear, which might determine how well you could make out the details. I never thought about the floor people walked on. Just assumed by saying nothing in the story, that the base floor was flat. With the size of the ring known it should be easy to find the curvature of the floor. For the ground floor, if it was flat sections laid end to end, the longer the piece, the greater the angle where they meet. If the joint was disguised by a wall, how small would the angle need to be, to not be noticed when crossing through a doorway. Once above the ground level, the floors would be flat, each building independent of the one next to it.

When writing a story, it is easy to build the cylinder really big by completely bypassing the ring look. I used one that was 5 miles long with a diameter of 1 mile. To get around how difficult it would be to build, that part was skipped by having it exist all built, before encountered in the story. In the middle of the cylinder, looking across the distance of a mile I'm not sure how the overhead view would appear. The details would shrink out of sight when taking in the whole view. Items to the left or right would be close and easily seen. As the view shifts to the overhead view, the details would shrink, which might be seen as a curvature. Or it might just look weird. I'll have to see how diminished the view is a mile away in reality.

The pictures of O'Neill Cylinders I looked at several years ago, are probably mostly imagined as looking the way they do, and because it is drawn from scratch it can be made to look exactly the way one wants them to look. There must be a lot of cgi work being done now where someone has built a city inside a big O'Neill ring where everything is imaged exactly the way it appears.

I did have a city inside my cylinder complete with rooms, walls, ceilings, windows, multiple floors. I simply imagined it as being flat, made no references to what the views looked like except to say that they looked like ordinary views, like you would see on Earth. That kept the writing simple in terms of the city inside the cylinder.

I did run across an article that talked about how the Coriolis effect would act on a pool of water on the floor, something you wouldn't notice in a small body of water. It appears that stuff on the floor would act the way it normally does in the presence of gravity. The same article also said that water poured from a glass, would pour out at an angle which would become noticeable after it fell a few feet. The short distance from water pitcher to glass wouldn't be seen, but a six foot drop could bend a few inches by the time it hit the floor. I guess it might be visible in a shower. I have no idea how big the cylinder was, but it was rotating fast enough to mimic normal Earth gravity.


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## SilentRoamer (Jun 30, 2022)

The idea of looking up and having a Sea float above my head just brought back some fantastic memories of how I imagined Rama!


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## SilentRoamer (Jun 30, 2022)

Venusian Broon said:


> We of Venus prefer the beauty of Saturn



So not only do you spout anti Jovian rhetoric but you are also unashamedly pro Saturnian!

We really need some moderators to come in here and deal with this.

Ill send Venus one of my spare moons! All Glory to the Great Red Spot!


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## Swank (Jun 30, 2022)

The classic SF anime Gundam and all of its direct sequels take place in and around O'neil cylinders. Gundam 0080 and Gundam Unicorn, for instance, has some reasonable footage of what that looks like from the inside.


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## Venusian Broon (Jun 30, 2022)

SilentRoamer said:


> So not only do you spout anti Jovian rhetoric but you are also unashamedly pro Saturnian!
> 
> We really need some moderators to come in here and deal with this.
> 
> Ill send Venus one of my spare moons! All Glory to the Great Red Spot!



Jove is really just a big puffy fat blob. Great Red Spot?!  If you like acne, I suppose it's great. 

Why not revel in the ever chaotic and complex interactions of the rings, the big hexagonal vortexes or actual interesting moons like Titan 



Anyway, going off topic a bit, I shall cheerlead Saturn elsewhere...


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## Venusian Broon (Jun 30, 2022)

DAgent said:


> Here's another thought that just came to mind. Would people living on the station notice the curvature of their "world" ? We don't really notice the Earths curvature, but on a cylinder the curvature is going the opposite direction. Would the residents notice this? Would there need to be a certain distance in the overall diameter to hide it? And how odd might it be to a visitor from Earth to see this, and likewise, if a Cylinder dweller visited Earth, would they find it off putting to not be able to see the rest of the "worlds" upwards curve?



I would say of course. We can see the Moon above us and that's about 384,000 km away. An O'Neil cylinder would need to be either have something in the middle to hide the 'other side', like weather or another cylinder. 

On Earth, I believe, our line of sight, on flat ground, is restricted to about 5km, but change your elevation - like go up a mountain or fly in an airliner and that can go up to 50km. With a cylindrical curvature I don't see any reason why you wouldn't see every surface all the way around - sure if it is very big, atmospheric haze and distance will smear out details. But again the International space station is about 400km above the Earth and it can make out quite a lot about the surface.


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## Orcadian (Jun 30, 2022)

DAgent said:


> Here's another thought that just came to mind. Would people living on the station notice the curvature of their "world" ? We don't really notice the Earths curvature, but on a cylinder the curvature is going the opposite direction. Would the residents notice this? Would there need to be a certain distance in the overall diameter to hide it? And how odd might it be to a visitor from Earth to see this, and likewise, if a Cylinder dweller visited Earth, would they find it off putting to not be able to see the rest of the "worlds" upwards curve?


Living on the inside of a cylinder (of feasible size) would at least banish the Flat-Earthers.


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## Orcadian (Jun 30, 2022)

Robert Zwilling said:


> ...
> I did run across an article that talked about how the Coriolis effect would act on a pool of water on the floor, something you wouldn't notice in a small body of water. It appears that stuff on the floor would act the way it normally does in the presence of gravity. The same article also said that water poured from a glass, would pour out at an angle which would become noticeable after it fell a few feet. The short distance from water pitcher to glass wouldn't be seen, but a six foot drop could bend a few inches by the time it hit the floor.


The Corolis effect inside a cylinder is gone into in delicious detail in Rama.


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## AllanR (Jun 30, 2022)

The very first one ever made? Or the ten thousandths --once most of Earth is turned into a park?


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## THX1138 (Jul 7, 2022)

I think it will be tubular dudes!

But really. I wonder what the atmospheric conditions at the center point of the tube would be like. What type of cloud or haze patterns from water condensation would there be and weather/wind patterns will come from it? Given the rotation, sunlight and everything else too.


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## Swank (Jul 7, 2022)

THX1138 said:


> I think it will be tubular dudes!
> 
> But really. I wonder what the atmospheric conditions at the center point of the tube would be like. What type of cloud or haze patterns from water condensation would there be and weather/wind patterns will come from it? Given the rotation, sunlight and everything else too.


With a 5 mile diameter, the center of the cylinder would be 13,000 feet high. However, the air pressure might be heavier than 13K on earth because the air in the center has no weight to make it settle. So you might get a temperature lapse rate and pressure drop that may be more like 0-6000 feet.

So I would expect clouds at maybe a middle elevation because the lapse rate is probably more like a curve with a fairly sudden drop somewhere in that middle. It would depend on what sort of average humidity the whole tube has. If there were clouds, they may be fairly permanent, or form daily with temperature. I would not expect any real wind.

It might be fairly easy to manufacture a daily rain shower with the right humidity and land cooling rate.


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## Robert Zwilling (Jul 7, 2022)

Some O'Neill Cylinders have slats on the outside wall. I saw one with 3 slats running lengthwise, those are for building on, with the empty space between each slat used for letting sunshine in.

I'm not great with math, can't visually visualize, but more than make up for that with mental creations that make anything possible.

An O'Neill cylinder could be built on Earth to see how the general mechanics work. If it was a closed environment, it might be possible to see what water would do. Easy enough to build a pond in it and extra water could be added to the air. Slat structure would allow light in. Put in plants and insects and see what happens. It wouldn't mimic what happens out in space where there is no gravity but it might show unexpected results that can only be seen easily by doing it. It could be a huge science fair project that would need its own tent.

First question for lack of math, does the cylinder spinning on Earth have to spin slower or faster than a cylinder spinning in space to keep the water in one place, such as a pond.

How big a diameter is needed so the items in the cylinder can interact with each other somewhat normally. I imagine a small diameter cylinder would have a greater impact on the items on the slats than a cylinder with a bigger diameter. Does orbital velocity on the slats appear to slow down for something on the slats as the radius of the cylinder increases. How big would the cylinder have to be to have some kind of hydrosphere situation created.

The slats in an O'Neill Cylinder in space are strobing the star light every two minutes if the cylinder is spinning 28 times an hour. That could be acceptable on a wide cylinder, with there being plenty of things to look at inside the cylinder. What would it be like with the outside view going by every two minutes.

For smaller structures, such as mining stations, or resupply depots, I envisioned the typical ring or a narrow cylinder used instead of a very long cylinder. Because the view would be limited inside the narrow space, and people like windows, I thought that the windows on the outside wall would be screens with stationary scenes on them. It could be what was out there in one particular direction by using cameras outside of the station providing views of the surrounding space. Or the window screens could provide views of space, other planet surfaces, such as Earth scenes. Rooms on the inside areas could even have window screen scenes. They wouldn't even have to be the sky, any old scenic view would do. 

On really big cylinders you could have farms. There are three or four ways that could go. Everything could be produced in an instant food maker, as found in every star ship. The other extreme is that food grown live is healthier than simulated canned food, in which case there would be a farm somewhere on board. Or there could be both natural and synthetic food materials. Once you have a farm, you don't need rocket scientists to do the farm work. Smart people might be needed to keep the energy system in balance. They had some pretty big farms in The Expanse. And then there was Silent Running.


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## THX1138 (Jul 7, 2022)

Swank said:


> With a 5 mile diameter, the center of the cylinder would be 13,000 feet high. However, the air pressure might be heavier than 13K on earth because the air in the center has no weight to make it settle. So you might get a temperature lapse rate and pressure drop that may be more like 0-6000 feet.
> 
> So I would expect clouds at maybe a middle elevation because the lapse rate is probably more like a curve with a fairly sudden drop somewhere in that middle. It would depend on what sort of average humidity the whole tube has. If there were clouds, they may be fairly permanent, or form daily with temperature. I would not expect any real wind.
> 
> It might be fairly easy to manufacture a daily rain shower with the right humidity and land cooling rate.


Thanks Swank. So maybe a light breeze at the most then? I forgot that the centripetal force from the rotation and gravity puss from the structure would affect the atmosphere also, thus a very light breeze. If I'm thinking correct. 

That would be interesting to see a tube-shaped haze in the 'sky'.


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## Swank (Jul 7, 2022)

Robert Zwilling said:


> First question for lack of math, does the cylinder spinning on Earth have to spin slower or faster than a cylinder spinning in space to keep the water in one place, such as a pond.


You can't build a spinning chamber on earth that makes earth's gravity go away, unless you built it with the centrifugal force of many Gs, making the earth's pull relatively negligible. I don't see how making a 10G environment is going to tell you much.


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## Swank (Jul 7, 2022)

THX1138 said:


> Thanks Swank. So maybe a light breeze at the most then? I forgot that the centripetal force from the rotation and gravity puss from the structure would affect the atmosphere also, thus a very light breeze. If I'm thinking correct.
> 
> That would be interesting to see a tube-shaped haze in the 'sky'.


Coriolis would produce wind if there is enough heat lifting or cool settling. But given the weird pressure gradients, there might not be a lot of that. 

I'm sure it would be relatively easy to model, though. I'm just talking off the top of my head.


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## THX1138 (Jul 7, 2022)

Robert Zwilling said:


> Some O'Neill Cylinders have slats on the outside wall. I saw one with 3 slats running lengthwise, those are for building on, with the empty space between each slat used for letting sunshine in.
> 
> I'm not great with math, can't visually visualize, but more than make up for that with mental creations that make anything possible.
> 
> ...


Yes! Silent Running...But not out in Saturn's orbit I would think. They would still have to be in the 'Goldilocks' zone if farming only by sun light. 
Father out from that you would need artificial lights. And maybe metallic/ceramic covered domes for more protection from space debris? In which case, those would bright full spectrum lights inside the domes. 

I have 2 NFT systems in the basement for growing lettuces in the winter, and the lights are close to the plants and are very bright! They grow well. Not the same as in pure full sun light, but good enough. A little thin in texture but good color and flavor in salads.  Oh, the lights are full spectrum LED's of the mid/mid-exp cost level.


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## Robert Zwilling (Jul 7, 2022)

Swank said:


> You can't build a spinning chamber on earth that makes earth's gravity go away


That can't happen and that's not what I am trying to find out. 

Assuming the O'Neill Cylinder is not parked in a bright light area, such as near a star, which is probably what anything far enough past Mars is going to experience in our solar system, the O'Neill Cylinders will need a light source. I guess the alternate slats with nothing in them would become lights connected to fusion power generators. The current space station has a schedule for lighting up the interior of the station so people's circadian rhythms remain normal. Apparently having sight has worked its way into the brain in ways that set up automatic functions that don't do so well in unstructured lighting situations. How long would it take humans to regulate these cycles naturally without structured lighting schedules or without resorting to drugs to keep everything balanced. In In The Expanse the belters born in low gravity had a very hard time with Earth's gravity. I guess they were still using light to keep the cycles balanced.


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## Swank (Jul 7, 2022)

Robert Zwilling said:


> That can't happen and that's not what I am trying to find out.
> 
> Assuming the O'Neill Cylinder is not parked in a bright light area, such as near a star, which is probably what anything far enough past Mars is going to experience in our solar system, the O'Neill Cylinders will need a light source. I guess the alternate slats with nothing in them would become lights connected to fusion power generators. The current space station has a schedule for lighting up the interior of the station so people's circadian rhythms remain normal. Apparently having sight has worked its way into the brain in ways that set up automatic functions that don't do so well in unstructured lighting situations. How long would it take humans to regulate these cycles naturally without structured lighting schedules or without resorting to drugs to keep everything balanced. In In The Expanse the belters born in low gravity had a very hard time with Earth's gravity. I guess they were still using light to keep the cycles balanced.


Please explain what you're trying to find out, because this was the question I was answering about using spin on the surface of the earth to produce artificial gravity. It certainly looks like you are asking how to spin something on earth to hold a pond in place:



Robert Zwilling said:


> First question for lack of math, does the cylinder spinning on Earth have to spin slower or faster than a cylinder spinning in space to keep the water in one place, such as a pond.


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## Swank (Jul 7, 2022)

THX1138 said:


> Yes! Silent Running...But not out in Saturn's orbit I would think. They would still have to be in the 'Goldilocks' zone if farming only by sun light.
> Father out from that you would need artificial lights.


I don't know if that is true. First, O'Neil cylinders require less light than the earth because of the thinner atmosphere, which is why their mirrors are at shallow angles rather than the full 45 degree mirror you'd want for one-to-one light gathering. Closer to the sun you would use an even shallower angle, further out a wider one. Once you're far enough from the sun that 45 degrees is maxed out, you could utilize multiple light gathering mirrors to increase the collection and concentration of sunlight. Large Mylar mirrors would be relatively cheap to deploy.


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## THX1138 (Jul 7, 2022)

Swank said:


> I don't know if that is true. First, O'Neil cylinders require less light than the earth because of the thinner atmosphere, which is why their mirrors are at shallow angles rather than the full 45 degree mirror you'd want for one-to-one light gathering. Closer to the sun you would use an even shallower angle, further out a wider one. Once you're far enough from the sun that 45 degrees is maxed out, you could utilize multiple light gathering mirrors to increase the collection and concentration of sunlight. Large Mylar mirrors would be relatively cheap to deploy.


That makes sense.


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## Wayne Mack (Jul 7, 2022)

Pure speculation, but I could see the axial center being very hot and humid with dirty clouds and even water.

Heat dissipation may be an issue as warm air rises towards the center, but unlike on Earth, air pressure does not slowly dissolve to zero. The only escape for heat is to radiate back out to the edges of the cylinder and this is not an efficient heat transfer mechanism.

Due to reduced levels of centrifugal force, I can see water vapor and dust particles would migrate towards the axis. These would tend to form dirty clouds. Due to the lack of a temperature drop, the water vapor may not return to a liquid state. If the humidity levels do become high enough, then there will be no outward pressure to force water drops to fall like rain. Due to suspend dust and dirt, the result would be a hot, muddy, non-flowing stream or river along the axis.

Overcoming this would likely require some sort of air circulation pumps to bring air from the center back out to the edges.


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## Swank (Jul 7, 2022)

Wayne Mack said:


> Pure speculation, but I could see the axial center being very hot and humid with dirty clouds and even water.
> 
> Heat dissipation may be an issue as warm air rises towards the center, but unlike on Earth, air pressure does not slowly dissolve to zero. The only escape for heat is to radiate back out to the edges of the cylinder and this is not an efficient heat transfer mechanism.
> 
> ...


You're still going to have a temperature lapse due to pressure decrease with altitude.

You might be able to force rain by seeding from the hub.

Or just keep humidity low.


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## Wayne Mack (Jul 7, 2022)

Swank said:


> You're still going to have a temperature lapse due to pressure decrease with altitude.


The heat, however, needs to go some place. In this scenario, there is a fixed volume, so continued expansion is not possible. This is essentially a pressure cooker. As Pressure = Temperature / Volume, increased temperature will create increased pressure. 


Swank said:


> You might be able to force rain by seeding from the hub.


One could form water droplets, but without an outward force at the center, there is no reason for the water droplets to fall to the outer edges.


Swank said:


> Or just keep humidity low.


Water, however, is a necessity for both human and plant life. A closed biosphere would require a significant amount of humidity.


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## Robert Zwilling (Jul 7, 2022)

Swank said:


> Please explain what you're trying to find out,


I was just trying to visualize how water behaves in an O'Neill cylinder. Its not real gravity, so it isn't really pulling things to the center of the situation. The rotation holds things in place away from the center? What happens to water vapor, would it rise or stay at "ground" level. The activity in the city would create heat that normally rises, but would it travel sideways and reach the center by over lapping layers piling up on top of each other. Maybe for normal precipitation a simple pipe down the middle of it could direct water to specific areas at specific times. Even then I don't think the rain would go straight down.


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## JunkMonkey (Jul 7, 2022)

psikeyhackr said:


> Robert Heinlein wrote a short story, It's Great to be Back, about a colony on the Moon. A consequence of this was everyone had to be relatively smart. The astronauts of the Mercury Program all had IQs of at least 130.
> 
> Would you want to live with dumb people in space?  How easy would it be to cause deadly emergencies?
> 
> So how would a society with only exceptionally smart people work?



This of course assumes that 'smartness' is an inheritable trait.  A train of thought which led Heinlein down some very dodgy paths.


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## Daysman (Jul 7, 2022)

This may have been covered, but wouldn't you need a_ heat sink_? 

Lighting the interior with (say) a half kilowatt per square metre means a lot of energy input. I suppose it depends how it enters and is distributed. I don't imagine you would lose it to space very quickly, not on this scale and at room temperature or less? 

Getting even more handwavy, if your habitat tracks the sun, the cap at the far end will be in permanent shadow, so I'm guessing an axial tail radiator would work, mechanically configured to modify its area — it may be very long. That would give you a manageable temperature gradient along the cylinder, so maybe snow on the 'shadow cap' wall and a moderate climate on the lower slopes?

I seem to recall everyone would live in accomodation stacked in the end caps, which would be shielded, maybe with water reservoirs or an ice shield? 

The cylinder might be a lightweight 'stage' for whatever landscape you want. Can't imagine any traditional farming — vertical farms would seem sensible, maybe tethers supporting them across the diameter...


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## Swank (Jul 8, 2022)

Wayne Mack said:


> The heat, however, needs to go some place. In this scenario, there is a fixed volume, so continued expansion is not possible. This is essentially a pressure cooker. As Pressure = Temperature / Volume, increased temperature will create increased pressure.
> 
> One could form water droplets, but without an outward force at the center, there is no reason for the water droplets to fall to the outer edges.
> 
> Water, however, is a necessity for both human and plant life. A closed biosphere would require a significant amount of humidity.


Considering that the center of the tube is at low pressure, it seems like the place the pressure could go is up.

Centripetal force provides "gravity" starting a little way from the hub, however the seeding system could use water pressure to create downward velocity.

Plants grow in deserts. Clearly there are ways of maintaining life at lower humidity levels - such as irrigation.


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## Swank (Jul 8, 2022)

Robert Zwilling said:


> I was just trying to visualize how water behaves in an O'Neill cylinder. Its not real gravity, so it isn't really pulling things to the center of the situation. The rotation holds things in place away from the center? What happens to water vapor, would it rise or stay at "ground" level. The activity in the city would create heat that normally rises, but would it travel sideways and reach the center by over lapping layers piling up on top of each other. Maybe for normal precipitation a simple pipe down the middle of it could direct water to specific areas at specific times. Even then I don't think the rain would go straight down.


It isn't gravity created by mass, but it is just as much the acceleration that provides the physics of gravity. The rain would not go straight down, but it doesn't go straight down on earth between wind and Coriolis forces.


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## psikeyhackr (Jul 8, 2022)

JunkMonkey said:


> This of course assumes that 'smartness' is an inheritable trait.  A train of thought which led Heinlein down some very dodgy paths.


I do not recall anything in the story providing any information about how old the Moon colony was with implications about the number born there versus allowed in from Earth after proof of competence/usefulness.


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## Swank (Jul 8, 2022)

Daysman said:


> This may have been covered, but wouldn't you need a_ heat sink_?
> 
> Lighting the interior with (say) a half kilowatt per square metre means a lot of energy input. I suppose it depends how it enters and is distributed. I don't imagine you would lose it to space very quickly, not on this scale and at room temperature or less?
> 
> ...


People wouldn't live in the end caps where there is no gravity but a lot of spin. They would live in the straight sections.

The amount of heat can always be controlled by shortening the daylight hours, as well as controlling the albedo of the 'land'. But heat can also be tapped off to produce electricity using the refrigeration cycle and radiators.

I agree that traditional farming would be misplaced - but edible gardens would be nice. The end caps may be great vertical farms since plants are unlikely to be bothered by the spin.


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## THX1138 (Jul 8, 2022)

One thing I found out is that the atmospheric pressure inside the cylinder is much less than that at sea level. So, less chance of a pressure cooker scenario it looks like. And when you look at the lay out, the strops of land are separated by equal sized strips of clear panels, to me are similar to the black and white stripes on a zebra. These strips are known to cause a micro air flow around the zebra in order to cool it down in the hot Savana sun. So, I think this may be the same in the cylinder also. 

Plus, the atmospheric conditions and temp can be controlled also by the amount of water vapor in the air. this can be gone at the hubs. 

Just some thoughts.


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## Wayne Mack (Jul 8, 2022)

Swank said:


> Considering that the center of the tube is at low pressure, it seems like the place the pressure could go is up.
> 
> Centripetal force provides "gravity" starting a little way from the hub, however the seeding system could use water pressure to create downward velocity.
> 
> Plants grow in deserts. Clearly there are ways of maintaining life at lower humidity levels - such as irrigation.


At best, the pressure at the center would equalize with that at the outer edges. Given the addition of centripetal force, it seems that the edges will always have greater air pressure. With a rotation speed of 28 revolutions per hour, at 100 feet or 30 meters from center, the effective gravity is 0.007 g. Together, these imply to me that there will be no outward pressure at the hub, which results in particles being collected there. This would include both water and dust and result in a muddy cloud or perhaps river.

Doing a little more reading, the design calls for a separate farming ring of larger dimensions (20 mile diameter vs 5 mile). Temperature control is purely radiant heat transfer.

One of the biggest challenges, though, would be the central axis. The design consists of two counter rotating cylinders joined by a central axis. Furthermore, the two cylinders constantly move together and apart to maintain direction. I wonder about the stresses placed on the axial rod and ball bearings supporting it. A single bearing failure could endanger the whole system and replacing a bearing while active would be a challenge.

Ref: O'Neill cylinder - Wikipedia


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## Swank (Jul 8, 2022)

Wayne Mack said:


> A single bearing failure could endanger the whole system and replacing a bearing while active would be a challenge.


Mag lev bearings?


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## Daysman (Jul 8, 2022)

Swank said:


> People wouldn't live in the end caps where there is no gravity but a lot of spin. They would live in the straight sections.
> 
> The amount of heat can always be controlled by shortening the daylight hours, as well as controlling the albedo of the 'land'. But heat can also be tapped off to produce electricity using the refrigeration cycle and radiators.
> 
> I agree that traditional farming would be misplaced - but edible gardens would be nice. The end caps may be great vertical farms since plants are unlikely to be bothered by the spin.



Eek!

No, not that high up — though the axis might be an interesting place to visit.

If the end caps are hemispheres, at 45 degrees incline the downforce is ~70% of that experienced in the cylinder valley, and the sloping area below is ~70% of the whole cap.

Might be a great place to build homes, with the view n'all.

Can't imagine farming there, but vertical farms maybe, except light would be way better in the valley, though (as mentioned in a recent post) it may be relegated entirely from the main habitat and, as you say, the whole valley given over to homes, swimming pools, restraunts...

But aren't these the early designs? Isn't radiation an issue?


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## Swank (Jul 9, 2022)

Daysman said:


> Isn't radiation an issue?


Water is excellent shielding, as are a variety of compounds with lots of hydrogen in them. If the forward hub was full of water or a lot of rock that would shelter the occupants from the radiation coming from the sun. I assume the reflectors could be built to only reflect useful light.


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