> there's no practical way to stick an atmosphere, much less a civilization composed of life forms that depend on gravity, to the inside of the sphere Why not

> there's no practical way to stick an atmosphere, much less a civilization composed of life forms that depend on gravity, to the inside of the sphere Why not spin the sphere? Given the immense surface area, it wouldn't even matter that the centripetal force would only be strongest around the 'equator'. So, the plan would be: 1. Create a giant rotating sphere around our Sun. 2. Create a ring world around the 'equator' of the inside of the sphere (i.e. a ring of walls high enough to hold in the resident's preferred atmosphere). 3. Install solar panels everywhere else. 4. Profit!