Suppose there was a ring of some material (steel? future carbon nano tubes?) around the sun. The ring would have a diameter of 2*10^9th meters. If a solar sail were placed attached to the ring with the reflector at a 45 degree angle) then the solar sails velocity would only be limited by the strength of the material (ability to handle the accelearation and for the ring to stay connected). Still, I calculate that even with the centrifugal force of 10^6 (the same acceleration experienced by a bullet) this would net a velocity of 1/10th the speed of light. So it could take about 40 years to reach the nearest star. The benefit of this means of gaining velocity is that all your energy would be provided by the sun free of charge...it would just take time for the solar sail to reach that speed. The total circumference of the ring would be equivalent to 25X the circumference of the earth...and you wouldn't need it to do anything more than hold together until the sail detached. Any thoughts?