PHYSICS A Philosopher's Stone COULD SUPERCONDUCTORS TRANSMUTE ELECTROMAGNETIC RADIATION INTO GRAVITATIONAL WAVES? BY GEORGE MUSSER MAKINGWAVES Like an ordinary magnetic field, a gravitomagnetic field exerts a force on moving masses at right angles to their velocity. The rotating earth, for example, generates a gravitomagnetic field that torques satellite orbits, as observations over the past several years have confirmed. The Gravity Probe B satellite, scheduled for launch early next year, should precisely measure this effect, which is also known as the Lense-Thirring effect, or "frame dragging." Even if Chiao's contraption works, it wouldn't allow the generation of antigravity fields, as...