AMHERST, Mass. - University of Massachusetts mathematics professor Robert Kusner chuckles as he recalls the scenes from the Star Wars movies, in which the spacecraft rapidly accelerates into hyperspace. "The stars wouldn''t smear if you were approaching the speed of light," he explains. "In fact, you wouldn''t see the light from behind or beside you, and all of the stars and constellations would appear to congeal into a single cluster ahead of you." Kusner, a differential geometer, knows hyperspace.