Abstract: Disclosed is a method and means for direct conversion of solar energy to mechanical energy through alternate warming and cooling of material consisting of highly aligned, high density polymer molecules. A strip of said material, when warmed by any means, contracts along its axis of alignment and such contraction can do mechanical work in a way mechanically similar to muscular contraction. A plurality of such strips mounted upon a rotor does work against gravity; the gravity field then returns the energy as torque.