On Monday, 26 September 2016 1:46:29 PM AEST Paul van den Bergen via luv-main wrote:
the biggest drawback for both the Niven ring and the Dyson sphere is there is no gravitational attraction inside the ring or sphere to the sphere - only towards the sun, or only on the outside....
The "original" Niven ring was spinning to provide centripetal force. A Dyson sphere could be spun to provide the same benefit on the inside at the equator, but that wouldn't work at the poles. https://van.physics.illinois.edu/qa/listing.php?id=1063 The Sun's gravity at Earth orbit is 0.0006 that of the Earth. A Dyson sphere of radius 1/22 of Earth's orbit would have a gravity on the outside that's about 1/3 that of the Earth (which is usable) but would have 484* the solar energy on the inside which might be good for industrial processes but not so good for providing a living surface on the outside. If an object is to be flexed then usually tensile strength is an easier engineering problem to solve than compressive strength. So a Niven ring would probably be constructed with more obtainable unobtainium than a Dyson sphere. https://en.wikipedia.org/wiki/Orion%27s_Arm Orion's Arm is interesting. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/