The Light Fantastic

Physics Professor Sidney Perkowitz illuminates a complex subject

By John D. Thomas

Because of a proofreading error, Sidney Perkowitz's new book, Empire of Light: A History of Discovery in Science and Art, rewrites one of the most important laws of twentieth-century physics.

"When I was working on the book, I made a vow that there would be no math in it whatsoever," explains the author from his bright, sunlit office in the O. Wayne Rollins Research Center. "And then I said, Oh you have to put in E=mc[squared], because people would be disappointed if you didn't.

"So I put it in, and damned if the proofreader didn't get it wrong. He wrote E=mc2, and it appeared like that twice on the same page."

The flub totally destroys the power of Einstein's famous equation, but Perkowitz has tried to take the mistake in stride. "Every time I autograph the book, I turn to the page where the errors occurred and hand correct them. Who knows, I might even increase the value of the book and might even restore some balance to the universe."

The main reason Perkowitz, who is the Charles Howard Candler Professor of Condensed Matter Physics at Emory, eschewed math in his new book was that he wanted it to appeal to as broad an audience as possible. One of his role models for the project was the late astronomer Carl Sagan. "He had been asked during his career, 'Why do you want to deliver this kind of science to the general public?' And Sagan said, and I'm paraphrasing, 'Two reasons. I want to share an exciting story, and if we scientists ever want to get funded in the future we had better convince people that what we're doing is worth funding.' I like that combination of an idealistic answer and a pragmatic answer."

It makes sense that Perkowitz would choose light as the subject for his first general-interest book, which Publisher's Weekly described as "a wondrous, mind-expanding tour of the visible world." Much of his career has been spent blasting various solids with laser light to see how they react. The results gleaned in his experiments have had high-technology applications. "I study silicon and other materials, such as gallium arsenide, which make up computer chips," says Perkowitz, who earned his doctoral degree in solid-state physics from the University of Pennsylvania in 1967 and joined the Emory faculty in 1969. "I help figure out more and more deeply how to manipulate these materials so you can make these wonderful things."

Perkowitz first became fascinated with light as a child growing up in New York City, when he visited the American Museum of Natural History with his father. "I can still picture this enormous hall full of crystals," he recalls. "I remember them being so fascinating and so beautiful in shape and color. I remember some huge pieces of stuff, like jade, sulfur, gold, and quartz. That image is crystal clear in my mind."

In Empire of Light, Perkowitz focuses on a different facet of his subject in each chapter. Areas of concentration include how the eye receives light and how the brain processes it; the history of the manipulation of light, from the torch to the candle to the light bulb to the laser; the exploration of the heavens using light; and the development of modern theories about light. He says that last section was perhaps the most difficult because it involved simplifying some extremely complicated physics.

Perkowitz says, "There are some sentences I spent hours on because to me, it's like the doctor's oath-first, do no harm. If I am a scientist and I am writing general science, that's great, but if I don't convey the science right, I think that's almost immoral. The trick is to find a way to say it right that's still understandable."

He says the single most difficult concept to describe was the fact that light is both a particle and a wave. "That's the most mysterious thing [about light] because . . . it's purely abstract." Perkowitz admits that he doesn't even understand the concept fully. "If I did," he says, "you could hand me the Nobel Prize for physics right now."

One theme woven throughout the book is light's association with art. Perkowitz used art as a motif to expand the book's potential appeal. "It's a different anchor that I thought might bring in a group of people who ordinarily wouldn't want to read a book about science," he says.

Perkowitz begins by showing how prehistoric artists were indebted to light. "The making and manipulation of light entered into art and changed how artists saw the world," he writes. "Paleolithic artists could not have painted their caves without illumination from small oil lamps. . . . The Paleolithic artists of Lascaux illuminated their caves with flickering reddish light from lamps that have been found these thousands of years later."

Perkowitz goes on to point out how modern sources of light have affected the work of artists, including that of the American painter Edward Hopper. He writes that the diner in Hopper's well-known painting Nighthawks is "isolated and adrift in urban nightmare darkness. . . . That mood comes partly from the brightly garish, shadowless fluorescent illumination inside the diner, in contrast to light from a street lamp shining on an exterior wall of warm red brick. The art historian Robert Hobbs calls the fluorescent light in the scene 'alienating and dehumanizing.' "

Perkowitz has already used material from his book in his astronomy classes and hopes to design a freshman seminar around Empire of Light. "I think the book could make a wonderful introduction to what science is all about and a little bit about what art is all about," he says. And because he enjoyed the project so much, Perkowitz says he is considering writing another general-interest science book.

"I'm thinking about one based on the old classical idea of the four elements-earth, air, fire, and water. You can interpret a lot of modern science through that very simple filter. And I would like to time it so that it's an end-of-century book, as everyone in the world is doing, so I'll jump on the bandwagon, too."

Photo by Ann Borden

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