Anton Sherwood wrote:
> absalomdraconis wrote:
>> If I was put in charge of such a [Ringworld] project, then I'd try
>> to design the ring so that individual segments were traveling at
>> just the right speed to maintain their orbit. The actual population
>> areas would be quite far from the center of mass. This pushes your
>> populous away from the sun if the center of mass is between sun and
>> habitat, or it allows the sun to pull them towards it if the
>> habitat is between center of mass and sun. This design would even
>> allow you to effectively have two rings in the same orbit. Note
>> that this would also probably require reflectors for the inner
>> ring, and maybe using lakes with clear bottoms to light the outer
>> ring.
>
> I am not seeing what you mean.
Sorry, I was probably too vague.
towards the sun, and the other away from it, making sure that their
collective center of gravity is orbiting fast enough to keep from
falling into the sun, and slow enough to stay in the same orbit.
Because the weight closer to the sun isn't moving at orbital velocity
for it's position, gravity tries to pull it towards the star, and
because the other weight is moving too fast for it's position, it'll
try to fly away from the star. Anything on trhe two weights will
experience the same forces.
Therefor, by building two ring structures, fastening them together,
and rotating them so that their collective center of mass is at
orbital velocity, you can have two ringworlds without needing the
stuff Niven's ringworld is built of.
absalomdraconis wrote:
>
> Take a long rope, and stick a weight to each end, then send one weight
> towards the sun, and the other away from it, making sure that their
> collective center of gravity is orbiting fast enough to keep from
> falling into the sun, and slow enough to stay in the same orbit.
> Because the weight closer to the sun isn't moving at orbital velocity
> for it's position, gravity tries to pull it towards the star, and
> because the other weight is moving too fast for it's position, it'll
> try to fly away from the star. Anything on trhe two weights will
> experience the same forces.
>
> Therefor, by building two ring structures, fastening them together,
> and rotating them so that their collective center of mass is at
> orbital velocity, you can have two ringworlds without needing the
> stuff Niven's ringworld is built of.
>
produce ~~ one gravity of "centrifugal" force on its inner surface. That's
the reason the Engineers had to invent scrith -- basically, to keep
Ringworld from stretching under its operational forces.
If you built a Ringworld and did not spin it rapidly, you'd need a lid to
keep all the air (and inhabitants) in. The small amount of centrifuge
effect generated by a two-level ring spinning at the orbital speed of their
collective center of mass wouldn't do the job, seems to me. And people
living on the inner ring would have hot feet, because gravity would have
them standing with their head away from the sun.
To compare with Ringworld's spin speed, orbital velocity for Earth is about
18 miles per second.
Steve
Sounds to me like the inner ring would prevent the populace etc. from
falling into the sun,
but the ring itself would be under Compression.
-Apparently you are expecting the connecting [cables] to ease the strain
of compression
for the inner ring while preventing the outer ring from flying apart.
An intriguing concept, now we just need to figure out the needed
strength and distribution
of the [CNT? cables].
RKH