A modification of Einstein's dynamics in the presence of certain states of space-time tension is proposed. The structure of the equations of motion for gravitational disturbances is very similar to Maxwell's equations for micro and macroscopic chiral bodies characterized by T, when the operators <img border=0 width=15 height=16 src="/fbpe/img/ingeniare/v16nespecial/image12-1.gif">and <img border=0 width=15 height=16 src="/fbpe/img/ingeniare/v16nespecial/image12-2.gif">are like <img border=0 width=128 height=21 src="/fbpe/img/ingeniare/v16nespecial/image12-3.gif">. The unification limit between the electromagnetism and gravity is discussed. As an application of this theory we mention the birefringence effect in GPS (Global Positioning Systems) systems.