Waves interfere with each other, sometimes adding, other times arriving out of phase and cancelling. Fringes are the result --- patterns in space of bright and dark, of high and low amplitude. Fringes of coherent light make holograms, records of a scene in three dimensions, spread out and encoded by the waves so that they store more than the flat image of a photograph. Fringes of radio signals sweep across the earth and are picked up by sensitive antennas; the fringes are then processed by radio astronomers to produce ultra-high-resolution maps of distant galaxies, as sharp as if taken by a telescope thousands of miles in diameter. Fringes of quantum mechanical wavefunctions interfere, constructively and destructively, to guide fundamental particles in their every motion around and between atoms.
And even the paths of macroscopic objects --- like stones, like planets, like us --- are determined by interference fringes in the objects' Lagrangian function, as it tries all possible paths and converges on the classical one that minimizes the integral of the mathematical action.
Friday, June 25, 1999 at 05:52:05 (EDT) = Datetag19990625