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Expanding Images of Our Universe, Part One: The Electron Microscope
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14175 |
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Section : |
NATURAL SCIENCE
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| Issue
Date : |
1 / 1988 |
3,777 Words |
| Author
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John E. Johnson Jr.
John E. Johnson Jr. is a freelance science and technology
writer and faculty member at the Johns Hopkins School of
Medicine. He is also editor in chief of two international
scientific journals.
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Editor's Introduction
Using light from the sun, our two eyes, and one brain, plus connecting communications channels, we produce images of the world around us. Yet our minds seek images of things we cannot see--things that are very small, buried in our bodies or far out in space, or deep inside the earth.
Several species can recognize themselves in a mirror, but humans alone ask the question "Who am I?" and consider the vastness of space and time. The human brain, with its trillion simultaneous chemical reactions, allows this singular phenomenon of self-awareness. Yet without the senses, especially vision, the brain would be isolated and unable to ask such questions.
A primitive brain evolved in fish several hundred million years ago, and through the ages it accumulated the functional elements that were to form one of the most complex entities ever designed by nature. As the brain evolved, sensory mechanisms also evolved to provide ever richer information about the surrounding environment. Vision developed along two paths: the compound eye, which formed a mosaic image in the tiny brains of arthropods (insects, crabs, and spiders), and the single-lens eye, which provided a camera-like image to the brains of fish, birds, and mammals.
The combination of the single-lens eye and a highly developed brain allowed humans to monitor a much larger environment than any other species. Humans could see predators as well as their prey at great distances and utilize intelligence to plan a course of action. However, the human brain's potential for comprehending the surrounding world far exceeded the limits of the naked eye to see every detail. Civilization would be several thousand years old before vision-extending instruments would allow mankind to stand in awe of Saturn's rings and the microcosm of a living cell.
The age of electronics took its first breath when the electron was discovered in the late nineteenth century. Only a few decades ago, with the utilization of silicon's unique properties as a semiconductor in computers, man's sphere of imaging began a time of rapid expansion. Fantasy became fact, dreams became reality, and through high technology, the human eye beheld the tiniest microbe and the faintest star.
In this series, "Expanding Images of Our Universe," we will examine the diverse technologies that have been and are being used
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