Originally posted by twhitehead
I think the idea of creating gravity using the spin would require such an enormously high spin rate that it would not really be viable.
The spin rate required to create a stable ring should be similar to the normal orbit of a planet whose diameter is slightly larger than the rings diameter (diameter of the rim, not of the whole ring).
I believe that ...[text shortened]... if the sun is not exactly in the center, the ring would tend to drift until it touches the sun.
Remember we are talking about a Niven ring, or is it Dyson? Not sure, I know Niven wrote the ring world series. And we are talking about a ring with a radius of 1 au, say 100 million miles, 160 million km. Did you do the math for that size?
I'll see if I can figure it out. Ok, with A=V^2/R, we'll make R+160 E6 Km or 160 E9 meters (1.6 E11 meters) and a velocity of 31,850 meters per second (that is about a one year orbit. It's interesting the distance from the sun has no bearing on what velocity the ring goes at.
So 31850^2=~1E9/1.6E11 =~.006 meters/second^2, about 1/1600th of a G. Not much. So we speed up. So we need about 1600 times the force, Square root of 1600, 40, so 40 times that 31850 m/s gives about 9.8 M/S^2 or one G of centripetal
force on the inside of the ring. That is about 10 days per revolution, roughly.
So if the ring spins with a velocity of 1200 km/sec you get about one G on the inside.
That works out to about 1.3 degrees or revolution per minute.