Gravity, Gizmos, and a Grand Theory of Interstellar Travel:
"Woodward’s MEGA drive is different. Instead of propellant, it relies on
electricity, which in space would come from solar panels or a nuclear reactor. His
insight was to use a stack of piezoelectric crystals and some controversial—but he
believes plausible—physics to generate thrust. The stack of crystals, which store
tiny amounts of energy, vibrates tens of thousands of times per second when zapped
with electric current. Some of the vibrational frequencies harmonize as they roll
through the device, and when the oscillations sync up in just the right way, the
small drive lurches forward."
What are the odds of this actually working?