Alla bella eta' di 97 anni...
Dal NY Times:
Fred L. Whipple, 97, Expert on Comets, Dies
By KENNETH CHANG
Dr. Fred L. Whipple, originator of the idea that comets consist of ice
with some rock mixed in, died Monday at a hospital in Cambridge, Mass.
He was 97.
His death was announced by the Harvard-Smithsonian Center for
Astrophysics, where Dr. Whipple had served as director for almost two
Dr. Whipple proposed his "dirty snowball" theory in 1950, diverging from
the popular belief then that comets were balls of sand held together by
gravity, to explain why some periodic comets seemed to be pulled along
by more than the force of gravity, arriving sooner or later than
He believed that as a comet approached the Sun, sunlight vaporized ice
in its nucleus and that the resulting jets of particles acted like a
rocket engine to speed the comet up or slow it down.
In addition, the glowing light from the tails contained particles that
Dr. Whipple conjectured had originated from frozen reservoirs in comet
"He put the study of comets on a scientific basis," said Dr. Brian G.
Marsden, director of the Minor Planet Center at the Harvard-Smithsonian
In 1986, close-up photographs of Halley's comet by the European Space
Agency's Giotto spacecraft proved Dr. Whipple correct.
Dr. Whipple often talked of his pride in an achievement during World War
II when he helped invent a device that cut aluminum foil into thousands
of fragments. The aluminum fragments, when released by Allied planes
over Germany, confused enemy radar by giving the impression that a much
larger number of planes were attacking.
In 1946, anticipating the future of space flight, Dr. Whipple invented a
thin outer skin of metal known as a meteor bumper or Whipple shield, to
protect spacecraft from high-speed particles. A colliding meteor
explodes when it hits the shield, and only vapor strikes the skin of the
spacecraft. The technology is still in use.
When the Soviet Union launched the Sputnik satellite in 1957, Dr.
Whipple was setting up a network of cameras to track it, and one station
was already operational. "He was all ready for Sputnik when everyone
else was wringing their hands and not knowing what to do," Dr. Marsden
President John F. Kennedy honored Dr. Whipple with an Award for
Distinguished Public Service in 1963 for the project.
Born in Red Oak, Iowa, in 1906, Fred Lawrence Whipple studied at
Occidental College in Los Angeles before completing his bachelor's
degree in mathematics at U.C.L.A. He turned to astronomy after a bout
with polio made it clear that he would not be able to fulfill his dream
of becoming a tennis champion.
He completed his doctorate in astronomy at the University of California,
Berkeley, in 1931 and then accepted a position at Harvard, starting on
Sept. 11 that year.
"Which was a Friday," Dr. Marsden said. "Why he started on a Friday, I
never quite knew."
Dr. Whipple was also director of the Smithsonian Astrophysical
Observatory in Cambridge from 1955 to 1973, which then merged with the
Harvard Observatory and renamed the Harvard-Smithsonian Center for
Astrophysics. The observatory employed only a handful of researchers in
1955; now there are several hundred.
"It grew like wildfire," said Dr. Myron Lecar, a senior astrophysicist
at the center. "Fred started that show off, and it's made an enormous
difference in U.S. astronomy."
While astronomers today often come from a physics background, "Fred came
from an earlier generation where they started from scratch learning
astronomy," Dr. Lecar said. "He was just shrewd. In fact, he was beloved
in Congress, because he talked in earthy language. He had a good feel
for what was true and what was noise."
Dr. Whipple retired from Harvard in 1977, although he continued to
bicycle to the center six days a week until he was 90. The license plate
on his car was "COMETS."
"Earlier on, he had 'PLANET,' too, when he had two cars," Dr. Marsden
Dr. Whipple was looking forward to the results from NASA's Stardust
mission, which collected samples from Comet Wild 2 in January. It is
scheduled to return them to Earth in 2006, which would have been in time
for Dr. Whipple's 100th birthday.
Dr. Whipple is survived by his wife, Babette; a son, Earle; and two
daughters, Sandra and Laura.
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"Physics is like ***: sure, it may give some practical
results, but that's not why we do it" (Richard Feynman)