
Will we ever build ringworlds? - tommoor
http://www.bbc.com/future/story/20150609-will-we-ever-build-ringworlds
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mcv
>"They are a solution in search of a problem."

No, they are not a solution, because they cannot work.

Also, I object to the article including the (immensely cool) Elysium space
habitat as a ringworld. It's not orbiting a star, and is completely unrelated
to Niven's Ringworld or any kind of Dyson sphere, apart from the fact that
it's in space and people live on it. It's a luxury space habitat, and
something that we actually may be able to build some day, unlike true
ringworlds.

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rbanffy
Well... Using a ring around a star to collect energy is much easier than a
ring that produces gravity by rotating at speeds much higher than escape
velocity. For one, it doesn't even need to be a rigid single structure but
could be a fleet of smaller machines simply orbiting the star.

Another worthy point is that rings and cylinders have a much better surface to
mass ratio than planets, so, with that mass of even a small planet one could
maintain a human population of many trillions.

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sliken
Heh, much higher than escape velocity is quite an understatment. I believe the
velocity required is a decent fraction of the speed of light.

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erikb
Uh, probably like most other people here I have to disagree. It's quite likely
that rings in one form or another will succeed. They are a simple and
efficient design. From space stations to rings around planets to rings around
stars there are many levels possible.

And some of the assumptions loook clearly wrong to me. Like the amount of
energy to increase the speed of an object of that size is certainly huge, but
it's much easier in space than on earth. On earth the faster you want to go
the more energy you ned for every additional kmh, but in space you don't have
all that annoying atmosphere to wiggle through. So you really just need a
constant amount of energy until you've reached your target speed and then you
just need to correct the speed and direction here and there.

The reasoning about the vast amount of ressources needed is correct but not
that much a problem, imho. No matter what you do. If you want to put millions
of people into space you need to invest a lot. But we certainly reach that
capability one day.

Last but not least, one thing were a ring is much much better than a
terraformed planet: Let's say we want to travel to another galaxy. Then having
a ring it's much easier to travel there than trying to move a planet out of
its orbit.

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jadell
If you have the technology and resources to move a ring of that size, then you
also have the technology and resources to move a planet. Ringworlds are many
orders of magnitude more massive than a single planet.

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ccvannorman
>"They are a solution in search of a problem."

The problem is that Earth won't last forever, and terraforming is limited to
existing terrain.

>"[Paraphrased] Making a ring world around a star would be colossal and it
would spin at 12,000 MPH!"

Why build it around a star? A ringworld a few miles in diameter orbiting a
star as the Earth does would be sufficient.

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mcv
I don't think it's fair to include wheel-shaped space habitats (like the one
from Elysium) with Niven-style ringworlds. The physics involved is totally
different on every possible level, and they are actually buildable.

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InclinedPlane
Rather unlikely. They would require enormous amounts of raw materials, would
need to be constructed out of things that are so far beyond the state of the
art they might as well be magic, and would be dynamically unstable besides.

Much smaller ring-shaped stations such as Banks' "Orbitals", quite likely, up
to the limits of material science. But I'd be surprised if any true ringworlds
existed in the entire Universe, or ever will.

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Shivetya
Let us be honest.

If we could why would we need too?

Really, if we had the technology and ability would not our tech out strip the
problems having a ringworld supposedly corrects?

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shalmanese
Is there even enough matter in the solar system to build a ringworld? Once you
start importing matter from other solar systems, the costs go up immensely.

