Super-habitats

Lucio, Mike, List members,

I am afraid that I have become somewhat obsessed with the idea if these
hyper-habitats, I have read about how Larry Niven had to invent a special
kind of unobtainium just to make his Ringworld work, I can understand this
as basically it is a single span bridge with out any ends but as I was
thinking about it I started to wonder if you really would need unobtainium.
All you really need is a material that can support itself and any load
against a 1G pull for the distance between any supports, that of course is
the rub, between any supports. The ring wouldnt have any supports or would
it?

If you scaled down the ring to the size we were discussing, 5,000Km wide and
15,000 long, the strength of the materials involved is much more realistic.
We were discussing the end caps of the cylinder not going all the way to the
centre but having a hole in the middle but without the hole then the end
caps could provide support needed to hold up the ring. So without the end
caps you would need super strong materials for the ring, with end caps, you
might be able to get away with more mundane materials. In order to hold in
the air you are going to need a wall/end cap, the question is how high do
you need them to be? The other question relating to end caps is if you
intend to have a hole in the middle you are going to need to either have a
very strong material to act as the support for the main part of the cylinder
or transfer the loading from the end cap material to the ring that
outlines the hole in the centre or (more realistically) a combination of the
two.

Assuming you have built your cylinder there was an option discussed, a long
rod with a number of counter-rotating cylinders attached to it, this
raises the question of the nature of the rod?

The final thing I have been thinking about with this kind of super-habitat,
is what it would be like to live on? It wouldnt make much difference if it
was a single ring or a series of rings arranged along a rod to a person
living on the surface.

Its a few hundred years from now, we have a couple of super-habitats and
you happen to live on one. With a cylinder 5,000 Km wide and 15,000 km long,
you will have as much room as we have on Earth (thank you Lucio:), your
house would be no different than what you have now. A structure as large as
this would generate its own weather, you could exercise a degree of control
here by changing the amount and location of heat and maybe moisture going
into system, this would need a lot of study. So with a normal weather
pattern you are going to need a house that can stand up to the forces
involved. On smaller habitats you would be able to tell you were living in
spin-gravity, by facing the right direction and turning suddenly you would
feel the push from coriolis effect, as the size of the habitat radius goes
up the size of the effect goes down, at some point you would not be able to
feel it, on something this size I dont think you would be able to.
Standing in your front yard (if you have a house and not an apartment) and
looking up you would see a blue sky and clouds (assuming normal dust sizes
and levels in the air and air with the same pressures and components as
here), the kind of sun you would see is open to question, there are a few
options here.

Going to work you might drive or you might have a short walk/bike ride to
the train station, there you could catch an electric train that would not
look out of place in any city on Earth or you might catch a high-speed
inter-city train, this might be something like the current trains we have
today or maybe a mag-lev type or maybe a real high-speed train, a mag-lev
train that runs outside the rim in vacuum at hyper sonic speed or perhaps if
there is a central axle you go up some kind of spoke, through the axle and
down a second spoke. These two transport methods would not be normal day to
day but would be like air travel today.

I have to wonder how you would know you were in a habitat, the ground
would seem flat to you, the ground curving above you might not be obvious
on something this size, it might disappear into the haze. There is the star
field at night but cities on the far side might look like stars, the sun
would look different and a central axle would stand out but is there
anything else?

I have to admit that this habitat design has intrigued me like no other, the
size of it makes it the equal to a planet but a planet with the advantages
of a habitat. The building of something like this would be akin to
terraforming and the size is such that if you make a small mistake in the
design of the ecosphere it would be absorbed. Even smaller super-habitats,
hundreds rather than thousands of kilometres would still be more like a
planet than what Ive always thought of as a habitat.

Thoughts anybody?

Darren