A Source of Light Science: Inventive JHU physicist Bill Fastie gave our world a different way of looking at others. And now, as retirement nears, he looks back at his own.

December 03, 1996|By Richard O'Mara | Richard O'Mara,SUN STAFF

Bill Fastie was just out of high school when he did his first physics experiment. He went around Baltimore with an instrument called a transmission diffraction grating -- a flat piece of glass with lines on it -- and aimed it at every neon sign he saw. From that he learned many had no neon gas in them. They were charged with argon or mercury gasses instead.

"But they were still called neon signs!"

Even today, at 80 years old, his final retirement from Johns Hopkins University approaching at the end of this month, Fastie conveys the flavor of his reaction: the exhilaration of his discovery colliding with the indignation at having his expectations undermined. It was Fastie's first eureka moment.

"I was 17 years old and hooked for life," he says.

The neon experiment was a small lift. But maybe not so small for a kid. Others would follow, discoveries that would make Fastie's name renowned in physics and astronomy, and eventually make Hopkins itself a research leader in both disciplines.

But there also would be disappointments, and here and there a failure. The most significant of these was the blurred vision of the Hubble Space Telescope, launched with great fanfare in 1990. Its problems threatened to undermine Fastie's reputation and robbed him of precious time to carry out the search that consumed his later years -- for another planet in a nearby solar system.

The single insight that made Fastie's name familiar among physicists throughout the world came routinely. There was no bolt from the blue. It kind of insinuated itself into his thought process during a discussion with a colleague at Leeds and Northrup, the Philadelphia instrument company where he was working in 1948. They were designing a spectrometer, an instrument for measuring the spectrum of a light source.

"I suggested we use one larger mirror rather than two [the standard for such machines], which would have to be adjusted to each other," he recalls. "It would be a more stable and rugged spectrometer."

At first it seemed just a deft way to improve a piece of hardware. But it did more. It adapted the spectrometer for space flight -- long before space flight was even on the horizon.

Within two years Leeds and Northrup had produced three such single-mirror spectrometers. Fastie, who had been hired two years earlier from the Hopkins physics department, returned to the university, where he was urged to publish a paper about his instrument. He would call it the Fastie Spectrometer. What else?

Such papers in scientific journals are the way scientists tell the world what they've done and keep up with what's going on in their disciplines. Fastie has published 84 scientific papers in his career. This one, in 1952, would be his third. He was determined to be careful; he wanted to be certain not only that he explained it clearly, but that he was the first to come up with the idea of the single-mirror spectrometer. So he asked around.

Nobody had heard of anybody else doing it. He looked in journals and found nothing. He was ready to send his paper off when he met a graduate student named Claud Rupert who remembered an article in a German physics magazine, published in 1902 -- a dismissive critique by one very influential scientist of the invention of another. The invention was a single-mirror spectrometer. The inventor was Hermann Ebert.

"I learned that I had reinvented the Ebert spectrometer," Fastie wrote years later in an article in Physics Today.

To this day in Baltimore, the instrument is referred to as the Ebert Spectrometer; Fastie will have it no other way. Elsewhere it is called the Fastie-Ebert Spectrometer, or the reverse. Sometimes it's just the Fastie Spectrometer.

And Hermann Ebert would be stunned to learn of the purpose to which their invention would be put.

The idea came to Fastie one night in 1957 as he stood outside his home with his wife Frances and watched the first satellite -- the Soviet Sputnik -- pass overhead. At that moment he suddenly knew two things: why he had reinvented the Ebert Spectrometer, and where he would send it. Eureka!

Two years later, in 1959, his machine was launched into space from Ft. Churchill, on the southern shore of Hudson's Bay. Its mission: to measure the ultraviolet, or nonvisible, light of the Aurora Borealis for the first time.

Since then it has gone into space about 30 times. It reached Mars in 1969 aboard the space craft Mariner, went into orbit and operated for 11 years. By analyzing the light emerging from the surface and atmosphere, it perceived a dry river bed, and proved that water once ran across the surface of the Red Planet.

"It flew by Venus [1978] and found oxygen in the atmosphere," Fastie says, "but oxygen which doesn't arise from the presence of water on the planet." It circled Venus, sending back data, for 15 years.

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