rincipal accomplishment of physics in the twentieth century. On July 20, 1976, a couple of weeks after the two hundredth birthday of the United States, an automated spacecraft landed on Mars and beamed back images of its red soil. The world held its breath as a robot searched for extraterrestrial life (and found none). As significant as the experiment itself was the manner in which the news was reported to the public. As a result of the universal spread of color TV, visual images began to supplant the written and spoken word which had been the principal carrier of news since antiquity. Science itself has long recognized the value of human vision enhanced by technology. To the telescopes, microscopes, and cameras of classical physics the twentieth century has added television, holography, and, most importantly, the computer. The field of computer graphics, which builds upon discoveries in modern physics, has in turn become an indispensable tool for basic research. In 1981 an ancient dream came true when the outlines of individual atoms were revealed to the human eye for the first time. The instrument that made this possible, called the Scanning Tunneling Microscope(STM), consists of a fine needle whose tip gently scans a surface the way a blind person's fingertip might scan an unfamiliar face. The digitized contours are fed into a computer which organizes them into a picture resembling the underside of an egg carton: each bump represents a single atom. Synthetic color coding adds to the contrast and helps to identify atoms of different species. The resulting map of the invisible atomic landscape we inhabit is imbued with a haunting beauty. In medicine the combination of computers with different probes has yielded equally dramatic results. Views of the brain produced by pencil-thin beams of X rays -- useless when considered individually -- are assembled by Computerized Axial Tomography(CAT) scanners into three-dimensional co...
