lor-coded images that have revolutionized neurosurgery. Ultrasound images of fetuses have benefited obstetrics. Other techniques for peering into the human body include Magnetic Resonance Imaging(MRI), which produced the picture at right, and Positron Emission Tomography(PET scanning), which records the radiation emitted when positrons from radioactive materials administered to the body combine with electrons in nearby cells. Even pure mathematics, the queen of the sciences aloof from the material world, has embraced computer graphics. The Mandlebrot set, for example, a mathematical structure whose delicate beauty and complexity fascinates mathematicians, artists, and computer whizzes, owed its discovery in 1979 to the emerging image-making capability of the computer. The generations of physicists after 1975 will not look at the world through glass lenses, but at its image on a computer monitor. What will they see?The news of the fall of the Berlin Wall (1989), the reunification of Germany (1990), and the disintegration of the Soviet Union (1991) rang out over an astonished world like so many peals of a great bell celebrating the end of the Cold War. As international tensions diminished and global trade flourished, the world seemed determined to make a fresh start. Physics, too, entered a new phase. The headlong rush into new discoveries that had started after World War II was slowing down, mainly because over the years science had grown cumbersome. Theories were becoming so complex that even super computers couldn't keep up with the calculational demands made upon them. Experiments in some branches of physics took years to plan and carry out, simply because they required enormous research teams, scientific instruments, and financial resources. Physicists took advantage of the new, more measured pace by going back to take a second, harder look at what had been discovered earlier in the century -- sometimes with surprising res...
