"Floating Halo" This is an oversimplification that assumes the earth is perfectly spherical, ignores gravitation pulls from objects other than the earth, assumes that a superstrong material could create a giant structure that can withstand enormous stress and that it's density is constant throughout. Imagine a large rigid halo (with a radius greater than the earth's) placed around the earth. The force "pulling" the halo towards the earth would be equal to the force pulling the halo on the opposite side. Would leave the halo "hovering" above the earth in a state of equilibrium? If so, because the centres of gravity of the earth and halo in the same place does this mean that the two objects are in equilibrium with each other? And also how amazing cool would it be to see a seeming straight platform float across the land?