Dyson sphere

A Dyson Sphere is a construct whose inner surface is approximately 1 AU from a star (the entire structure being a little more than 2 AU in diameter). This allows for a very large surface area capable of supporting life. Gravity (through the mass of the structure, or by artificial mechanics) would essentially pull everyone 'down' towards the hull and away from the star. Topsoil, and atmosphere would most likely be present between the hull of the sphere and the star.

The Dyson Sphere was first theorized by Freeman Dyson.

The Dyson Sphere in (NF novel: Double Helix) would appear to be of different dimensions, as when one falls from the 'top' of the inside of this sphere, gravity pulls that person to the 'bottom' of the sphere rather than to the hull. Also, in this case, a Romulan cloaking device may have been used to hide the sphere, but the gravity well it created would be quite noticeable.