Adventures In Lilliput

Think small. Now think smaller still. For in the lilliputian wonderland that scientists have begun to explore, a grain of rice looms as large as an asteroid, a droplet of water as wide as an inland sea.

Using powerful new tools, biologists at the University of Chicago have gently sliced through a red blood cell to peer at individual protein molecules clinging to its inner membrane. At the California Institute of Technology, chemists have watched in wonder as a hydrogen atom romances an oxygen away from a carbon dioxide molecule. And at Stanford University, physicist Steven Chu has mastered techniques for levitating millions of sodium atoms inside a stainless-steel canister and releasing them all at once in luminescent fountains. Of late, Chu and his colleagues have amused themselves by stretching a double-stranded DNA molecule as taut as a tent rope. When they ! release one end, the molecule recoils like a miniature rubber band. Boing!

Just as improvements in navigational tools opened the oceans to sailing ships, so a new generation of precision instruments has exposed a breathtaking microworld to scientific exploration. Aided by computers that convert blizzards of data into images on a screen, these instruments are helping scientists see -- and even tinker with -- everything from living cells to individual atoms. "This technology is still pretty crude," marvels Chu. "Who knows what we may be able to do with it in a few years' time."

Among the instruments generating excitement:

FEMTOSECOND LASERS. Like strobes flickering across a submicroscopic dance floor, these devices can freeze the gyrations of atoms and molecules with flashes of light. The lasers are being used to study everything from how sodium joins with other atoms to form salts to how plants convert sunlight into energy through the process of photosynthesis. Physicists from California's Lawrence Berkeley Laboratory reported that they used such a laser to take a "snapshot" of the chemical reaction that is the first step in visual perception. This reaction, triggered when light hits the retina of the eye, had never before been directly observed. And with good reason. The reaction was clocked by the L.B.L. team at 200 femtoseconds, which are millionths of a billionth of a second. How fast is that? Well, in little more than a second, light can travel all the way from the moon to the earth, but in a femtosecond it traverses a distance that is but one hundredth the width of a human hair. "This sort of time scale is almost impossible to imagine," exclaims L.B.L. director Charles Shank, who helped pioneer the technology.

LASER TRAPS. Beams of laser light can also be used to ensnare groups of atoms, which can then be moved around at will. But because atoms at room temperature zoom about at supersonic speed, they first have to be slowed down. In 1985 the invention of "optical molasses" by a research team at AT&T Bell Laboratories provided an ingenious solution to the problem. As its name implies, optical molasses uses light to create enough electromagnetic "drag" to bring wildly careering atoms to a screeching halt. Because the atoms lose virtually all their kinetic energy, they approach the perfect stillness of absolute zero, the frozen state at which motion ceases.