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Fred Lawrence Whipple

During his lifetime, American astronomer Fred Whipple (1906–2004) was recognized as the world's leading expert on solar system astronomy. Before Whipple came along, scientists believed comets were nothing more than loose clouds of dusty vapor held together by gravity. In 1950, however, Whipple proposed that comets were really enormous rock–embedded ice balls surrounded by gas and dust. His so–called "dirty snowball" theory remained controversial until 1986, when a spacecraft photographed the icy contents of Halley's comet, proving Whipple's 36–year–old theory to be accurate. Besides comets, Whipple dedicated his life to studying other components of the solar system. His work helped scientists around the globe better understand the universe and also helped pave the way for spaceflight.

Discovered Astronomy in College

Whipple was born November 5, 1906, in Red Oak, Iowa, to farmers Harry Lawrence and Celestia (MacFarland) Whipple. When he was in his teens, the Whipples left the family farm and relocated to Long Beach, California. Once there, Whipple worked as a clerk in his father's grocery store. He graduated from Long Beach High School in 1923. From 1923–24, Whipple studied at Occidental College in Los Angeles, California, and dreamed of a career in tennis. He later transferred to the University of California at Los Angeles (UCLA).

In an August 2000 issue of Science, Whipple wrote about his childhood. "As an Iowa farm boy, I contracted a case of polio and it prevented me from becoming a professional tennis player. When I entered the University of California at Los Angeles, it was still my main ambition to excel at tennis. A mathematics major enabled me to bring home good grades without having to spend much time on studies. But I never made the tennis team."

During his junior year at UCLA, Whipple took a course from famed astronomer Frederick Leonard, founder of the Meteoritical Society. Studying the science of the universe and its matter intrigued Whipple. He began to focus more on astronomy and less on mathematics, though he completed his studies in mathematics, earnings his degree in 1927. By then, it had become clear to Whipple that he had to give up his dream of playing professional tennis. Instead, he turned his full attention to astronomy and with Leonard's help, secured a teaching fellowship in astronomy at the University of California at Berkeley.

While studying at Berkeley, Whipple learned how to compute the orbits of celestial bodies, such as meteors, comets and planets. He was part of a team that calculated the orbit of the newly discovered planet Pluto. After graduating with his doctorate in astronomy in 1931, Whipple became head of the observing program at the Harvard College Observatory. Once there, he stayed for more than 70 years. When Whipple first went to Harvard, he was interested in studying galaxies, but his boss made it clear that he would be the one studying galaxies. Whipple decided to focus his attention on comets; it became the pursuit of a lifetime. Whipple cautiously examined the "sky–patrol" photographs taken regularly at the observatory and over the course of a decade, discovered six new comets and computed their orbits. He also began to study the behavior of comets, photographing them as they moved in their egg–shaped orbits around the sun.

Helped WWII Bombers Trick Enemy Radar

After the United States became involved in World War II, Whipple left the observatory to work in the office of scientific research and development at the Harvard Radio Research Laboratory. He stayed there from 1942–45. During this time, Whipple worked on radar countermeasures. He co–invented a razor–sharp device that cut aluminum foil into tiny slices called chaff, which were dropped by bombers as they approached enemy radar, thus confusing the readings. Dropping the aluminum slices made it appear like there were more aircraft in the sky than in reality. In 1948, Whipple earned a Presidential Certificate of Merit for this invention.

After the war, Whipple returned to the Harvard observatory and his study of comets. He believed spaceflight was just around the corner and in 1946, Whipple invented a "meteor bumper" to protect spacecraft and satellites from collisions with space debris. The device, known as the "Whipple shield," is made up of thin layers of metal that surround the body of a spacecraft a few inches out from its surface. The bumper absorbs the impact when the craft strikes another object. As the 21st century began, the device—with some updates—was still being used on virtually every interplanetary spacecraft put into orbit. Whipple thought of himself as part inventor, part astronomer. Reading his 2004 obituary in the Boston Globe, this is clear: "I'm an engineer at heart," he once remarked, according to the paper. "I've been able to judge what instruments will work and what can be built. That's been the secret to my success."

Developed "Dirty Snowball" Theory of Comets

As Whipple continued his study of comets, it became clear to him that comets had an icy core. At the time, most scientists believed comets were merely dusty orbiting clouds of vapor, sand and rock. Comets were thought of as "floating sandbanks" held loosely together by gravity with no solid core. A minority of scientists believed comets were rocks spewed out by volcanoes on Jupiter and Saturn. The comet's spectacular tail had also troubled scientists. It seemed impossible to think that a comet had enough material to keep emitting its tale without getting smaller and smaller and eventually disappearing. Whipple theorized that comets were really balls of gas, rock and dust with an icy nucleus. He published his so–called "dirty snowball" theory in the March 1950 issue of the Astrophysical Journal. Controversy ensued.

During his studies, Whipple discovered that comets did not act like other bodies in the solar system. They did not adhere to the simple Newtonian mechanics of other bodies—they weren't predictable. Some comets reached the Earth earlier than expected; others were late. Because of this, Whipple theorized that some unknown force—besides gravity—was affecting the comets. Whipple believed that comets were really large masses of dust and ice that vaporized as the comet approached the sun and refroze as it receded from the sun. He theorized that when a comet approached the sun and began to evaporate, it released its frozen water. This trail of vapor not only produced the fabulous tail but also caused propulsion jets that propelled the comet forward, at times altering its orbit. Whipple's theory was much–debated until 1986, when the European Space Agency's Giotto spacecraft got near Halley's comet and snapped pictures of an icy core, proving his theory.

Whipple's idea was "one of the most important contributions to solar system studies" in the twentieth century, Smithsonian Astrophysical Observatory astronomer Brian Marsden told Boston Globe staff writer David Chandler.

What amazed Whipple's colleagues most about his discovery was that Whipple made the conceptual leap based mostly on intuition, sparked by a little data. Speaking to the Los Angeles Times, Harvard–Smithsonian Center astrophysicist Mike Lecar summed up Whipple's significance this way: "Unlike other great physicists, he had uncommon common sense. He just looked at things with a fresh eye."

By 1950, Whipple was a full Harvard professor of astronomy. In 1955, he also became director of the Smithsonian Astrophysical Observatory after it moved from Washington, D.C., to Cambridge, Massachusetts. He held that position until 1973. During his years at Harvard, Whipple wrote many papers and books and inspired many future scientists, including astronomer Carl Sagan, whose 1980 PBS series "Cosmos" helped popularize astronomy. Whipple's 1941 book, Earth, Moon and Planets, also popularized the study of the skies by explaining solar system astronomy to the masses.

Whipple was also one of the first scientists to envision the coming age of satellites. In the late 1950s, he set up a satellite tracking program called "Moonwatch." Participating in the program were several observing stations around the world, all equipped with special sky–watch cameras, and a network of amateur astronomers who volunteered to watch the skies. When the former Soviet Union launched Sputnik, the first artificial satellite, in 1957, Whipple's "Moonwatch" team was able to track its progress around the globe. Virtually all information about the satellite that went to the media and public came from Whipple's "Moonwatch" program. President John F. Kennedy presented Whipple with the Distinguished Federal Civilian Service Award in 1963 for this work. At the time of the launch, tensions between the Soviet Union and the United States ran high. U.S. citizens were concerned about having the Russian satellite fly over their country, but Whipple's data eased fears. Whipple was proudest of the award he received for this work. "I think that was my most exciting moment, when I was able to invite my parents and my family to the Rose Garden for the ceremony," he once said, according to the Los Angeles Times.

During the late 1960s, Whipple joined fellow astronomer Aden Meinel in creating the first multiple–mirrored telescope. It started when Meinel told Whipple about six large telescope mirrors the Air Force was getting rid of. Working together, the two invented a multiple–mirror telescope, which collected light from the six mirrors, then focused it onto a single camera. Synthesizing the light from the six mirrors into one image made the telescope perform like a much larger telescope than it was. The multiple–mirror telescope, located on Arizona's Mt. Hopkins, was dedicated in 1979. It held the honor of being the world's third–largest telescope for two decades. In 1982, the Mt. Hopkins Observatory was renamed the Fred Lawrence Whipple Observatory.

Continued Work into his 90s

Over the course of his career, Whipple made many contributions to the field of astronomy. Besides determining what comets are made of, he also figured out that meteors are made of particles that come from within our solar system, rather than from particles arriving from outside the solar system, as some believed. Whipple also used satellite data to learn about the Earth's upper atmosphere and its daily changes. In addition, he helped advance the types of technology used in studying space. In 1968, the world's first space telescope, called the Orbiting Astronomical Observatory, was launched, thanks to Whipple. Though this telescope had a mechanical malfunction that led to its failure, it helped pave the way for the Hubble Space Telescope. "Fred had the vision very early about a telescope in space," Eugene Shoemaker told the Boston Globe's Chandler. "He was talking about this before there was a NASA." For his many contributions to our understanding of the solar system, minor planet No. 1940 was named after Whipple in 1975.

Whipple retired in 1977, though as a professor emeritus, he continued his daily treks to his Cambridge, Massachusetts, office. Until he turned 90, he biked the three miles to his office nearly every day. He continued his work at the observatory almost until the end of his life. Whipple was well–known in the Cambridge area—easily identified driving his car, whose license plate read COMET.

Whipple died August 30, 2004, in Cambridge. He was 97. Whipple was survived by his first wife, Dorothy Woods, and their son, Earle. Whipple and Woods married in 1928 and divorced in 1935. He was also survived by his second wife, Babette Samelson, whom he married in 1946. They had two children, Sandra and Laura.

Periodicals

Boston Globe, October 28, 1996; August 31, 2004.

Guardian (London), September 2, 2004.

Independent (London), November 13, 2004.

Los Angeles Times, September 1, 2004.

Science, August 4, 2000.

Times (London), September 4, 2004.