Ringworlds

[Vortex]

Originally posted by Suicide Junkie:
The outside is metal, the inside is where you grow your crops and put your houses, since that's the side the sun shines on.

You might want to model the sphereworld as a set of "arc" planets. If you also tilt the ring, then ships will be able to fly inside.

Be careful not to confuse ring-worlds and spher-worlds. The latter should, correctly be called dyson spheres and as such will completely enclose the star.

This means that for most purposes the star doesn't exist, all you see is the 'metallic' outside of the planet. A very large planet at that - the exact size dependant upon where the 'habitation' zone for the star type falls. For G3 type stars, eg Sol, thats 1AU - the distance between the Earth and the sun.