Gravity up close: Looking for extra dimensions by measuring gravity at the microscopic level: "A new detection apparatus proposed by the National Institute of Standards and Technology in Boulder, Colo., hopes to explore gravity at the 100-1,000 nanometer level -- larger than atoms but many thousands of times smaller than any previous experiment has achieved. They hope to measure gravity over the shortest range yet.
Their apparatus consists of a tiny glass bead suspended in vacuum by laser beams. A gold rod is swept past the bead, disturbing its place in the laser beams. The bead then oscillates back and forth, and this pendulum-like motion provides a way to precisely measure the force of gravity between the rod and the bead."