1929-

American astronomer who discovered the first apparent "superluminal" sources, using very long baseline interferometry. Superluminal jets appear to be moving faster than the speed of light because they are pointed almost directly at or away from the Earth, causing the illusion of having a velocity that is impossible to achieve. This discovery was the first indication that events can take place in the universe that would create such long-lived and fast-moving beams. Superluminal jets have been noted in a number of quasars and other active galaxies as well as in a few very active star systems.