Telescopes and microscopes. New technology is extending the maximums and minimums of our viewing power, providing new perspectives on the cosmos as well as the infinitesimal
Boston — PLAID-SHIRTED and poker-faced, David Kennedy peers into what looks like the radar screen of a ship at several milky spheres flickering in neon green. The objects, less than 1/100 the size of a sugar crystal, are part of an animal cell displayed on a new microscope system. What's unusual, though, isn't their small size but the way the cells are seen: alive and in three dimensions.
``This is the first time this has been done,'' says Mr. Kennedy, a graduate student at the Massachusetts of Technology (MIT) here, where the system was developed.
The new microscope technology is one of several recent advances that are pushing back the frontiers of man's ability to probe and ponder the universe of the minute. The new generation of magnifiers could lead to significant discoveries in many different scientific fields, with implications for everyone from chemists to computer-chip makers.
``Every one of these little breakthroughs means tremendous advancements waiting in the wings,'' says Ronald Gronsky, senior scientist at the University of California's Lawrence Berkeley Laboratory, who runs the world's most powerful electron microscope.
The microscope has already evolved a long way since Anton van Leeuwenhoek peered through a glass bead in 1674 to discover ``animalcules'' swimming in a drop of water. Today's most powerful spyglasses on the small, electron microscopes, can detect objects down to the atomic level. Now scientists are pushing magnifications even further, as well as making some instruments perform new tricks altogether. Some recent developments:
3-D viewing. Peering at microscopic objects in three dimensions is not new. But Prof. Alan Nelson and his colleagues at MIT's Whitaker College of Health Sciences, Technology, and Management appear to have pushed the concept a step further. They have linked a powerful computer with an electron microscope and a special viewing system that, early results indicate, give more accurate 3-D images of objects and at higher resolutions than systems in the past.
The still-nascent process is also allowing the first glimpses of live cells in three dimensions. In conventional electron microscopy, living cells usually don't survive the tortuous preparation for viewing. The tiny specimens are usually fixed with chemicals, then stained to provide contrast, and finally freeze-dried. Depending on the system, they are also either sliced thinly or coated with a metal film -- all deadly to a cell.
To skirt this, MIT scientists designed a special chamber that preserves the cells while allowing electrons to squirt through. Using a computer and a desk-size 3-D displayer, the system provides rare glimpses of the internal structure of microscopic matter, not just the surface.
Already, biologists involved in brain and drug research are using the ``microtomography'' process to explore the catacombs of cells and learn how materials travel through them. Materials scientists are interested in it to help gauge the strength of ceramics. In the future, it might be used by oil engineers in studying the structure of rocks and by chipmakers in spotting flaws on electronic circuits.
X-ray microscopy. Another way to view living cells is with microscopes that use X-rays instead of electron beams. Although not as powerful as their electron brethren, X-ray microscopes are now emerging that have much higher magnifications than conventional light microscopes and that will also capture cell life in action. They hold other trump cards, too: X-rays penetrate matter better than electrons, so, again, specimens don't have to be sliced so thin. Nor are all the other cumbersome preparations needed.
Scientists at IBM recently came up with a new ``contact'' X-ray technique that is believed to be yielding some of the most intricate details of the internal fabric of cells yet produced. The system uses long-wavelength (``soft'') X-rays that do kill cells. But the flashes of radiation are so brief -- 1/10,000,000 of a second -- that the ``snapshots'' are taken before damage is done.
The system was first used to look at parts of human blood cells. But the images of their internal structures were sharp and detailed enough that researchers are convinced the technique could prove invaluable in many areas of biology and medicine. The system may also be adapted for such uses as inspecting computer chips.
For now, though, the microscopy technique is so new that scientists aren't even sure what they are seeing. ``I feel we are in about the same'' position that the electron microscope was ``40 years ago,'' says Ralph Feder, an IBM scientist who has been working with a team of medical researchers.
Mightier electron magnifiers. Perhaps the biggest leap forward in exploring microspace will come later this year, when University of Chicago physicist Albert Crewe begins testing his new electron microscope.
The machine is expected to be the most powerful magnifier in the world -- capable of showing details down to one-half angstrom (two-billionths of an inch). The electron microscope at Berkeley reveals details down to 1.6 angstroms.
Dr. Crewe's instrument would be the first one capable of observing the atomic structure of almost any solid material. The British-born inventor, who built the first microscope able to take pictures of a single atom, expects his new 3,000-pound machine to produce even sharper images of the arrangements of atoms in small groups.
Such snapshots could prove a boon in the study of ceramics, metallurgy, electronics, chemical catalysts, and biology -- and may open up new frontiers to research. The $1.5 million-plus machine has been under construction for two years. Crewe says that at this point, ``all theoretical expectations are that it will work.''
If so, today's new generation of Gullivers will have one more tool for exploring that vast and invisible land of Lilliput. Magnifying the microscopic. The microscope, once as simple as a glass bead, is now often a refrigerator-sized device capable of magnifications in excess of 200,000 times. Today's finest instruments detect objects down to six billionths of an inch. Now some new instruments promise to improve on this, while others will show detalils of living cells and in three dimenstions.All promise incalculable payoffs for scientists. Certainly, the moicroscope has evolved a long way since this 1686 version shown below. 3-D viewing. Harnessing an electron microscope to a powerful computer and special viewing system, Prof. Alan Nelson and his colleagues at MIT have produced some ot the first three-dimensional pictures of living cells. The system is also yielding new details on the internal structure of imcroscopic matter, which may prove a boon to everyone from biologists to geologists. -- 30 --