Number 151 (Story #5), November 15, 1993 by Phillip F. Schewe and Ben Stein MOLECULAR DYNAMICS (MD) SIMULATIONS have gotten faster. These computer studies track the behavior of a hypothetical ensemble of particles subject to a specific law of motion incorporating the complex interactions among neighboring particles. As part of a study of supersonic projectiles, scientists at Los Alamos have simulated the 3-dimensional movement of 180 million particles, with 4 updated configurations per microsecond. Less than a year ago, the largest comparable MD simulation tracked 17 million particles. The Los Alamos computer system had a sustained speed of 50 Gigaflops. (Physics World, Oct. 1993.)