[meteorite-list] Comet Pioneer Fred Whipple Dies

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Aug 31 12:07:46 2004
Message-ID: <200408311607.JAA14158_at_zagami.jpl.nasa.gov>

http://news.bbc.co.uk/1/hi/sci/tech/3614064.stm

Comet pioneer Fred Whipple dies
By Dr David Whitehouse
BBC News
August 31, 2004

Fred Whipple - the astronomer who first correctly described comets as
"dirty snowballs" - has died aged 97.

He revolutionised the study of comets when in 1950-51 he proposed that
they were not "sandbags" but small bodies made or rock, dust and ice.

He also predicted the coming of artificial satellites and was prepared
with a satellite tracking network when Sputnik was launched in 1957.

He discovered six comets, all of which were named after him.

Chief of Chaff

Fred Whipple began work at the Harvard College Observatory in 1931 and
from 1955 to 1973 directed the Smithsonian Astrophysical Observatory,
helping it to become the renowned Harvard Smithsonian Center for
Astrophysics.

Working for the US Air Force during World War II he came up with the
idea for chaff - little bundles of shredded aluminium foil that could be
dropped from US aircraft to confuse German radar. Air Force wits dubbed
him the "Chief of Chaff" as a result.

Fred was one of the truly great forces in astronomical research, and our
field has gained immeasurably as a result of his insights
Don Yeomans, Jet Propulsion Laboratory

But it was his work on the icy conglomerate model for comets that is
regarded as the highlight of his distinguished career.

"This was a complete paradigm switch since back then the consensus model
for a comet was a flying cloud of particles," Don Yeomans, of the Jet
Propulsion Laboratory in California, told BBC News Online.

"It had been so since the late 19th Century when comets were identified
with meteor showers."

But Whipple knew that some comets have been orbiting the Sun a thousand
times and more. If they were nothing but sand, they would have broken up.

In 1950, he published a paper suggesting they were "icy conglomerates";
what the media later called "dirty snowballs."

As the comet gets closer to the Sun, the ice vaporises and forms a
spectacular coma, or tail. When in 1986, the Giotto Mission came close
enough to Haley's Comet to photograph its nucleus, it looked just the
way Whipple described it 36 years before.

Whipple's model allowed the so-called nongravitational forces acting on
comets to be understood. The rocket-like thrusting when the ices began
to vaporise produced a small but noticeable thrust that needed to be
accounted for so that the motions of active comets could be modelled far
more accurately.

Flow of knowledge

Whipple also made contributions in fields as diverse as variable stars,
galaxies, stellar evolution, supernovas, the interstellar medium, radio
astronomy and astronomical instrumentation.

He was also the first to compute an accurate orbit for the then recently
discovered Pluto.

While his collected works were published in two large volumes in 1972,
he continued to publish research studies for at least another quarter
century.

"Fred was one of the truly great forces in astronomical research, and
our field has gained immeasurably as a result of his insights," says Don
Yeomans.

"While a bit in awe of him, I quickly realised he was completely
unaffected by his fame.

"It really didn't matter whether one was a very young and inexperienced
scientist or a well established, distinguished scientist.

"He treated everyone with the same kindness and respect."


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http://www.tucsoncitizen.com/breaking/083104_obit_whipple.html

Astronomy pioneer Fred L. Whipple dies at age 97
The Associated Press
August 31, 2004

CAMBRIDGE, Mass. - Fred L. Whipple, a pioneer in astronomy who proposed
the "dirty snowball" theory for the substance of comets, has died. He
was 97.

Whipple died Monday at a Cambridge hospital, the Harvard-Smithsonian
Center for Astrophysics said Tuesday.

Whipple proposed the theory in 1950, saying that comets consisted of ice
with some rock mixed in, rather than sand held together by gravity, as
was widely believed. Whipple's theory was an attempt to explain why some
comets seemed to arrive at destinations earlier or later than predicted.

Whipple believed that as a comet approached the sun, its light vaporized
ice in the comet's nucleus. The jets of particles that resulted acted
like a rocket engine that either slowed or accelerated the comet.

He also theorized that the glowing comet tails contained particles that
originated from frozen reservoirs in comet nuclei.

Whipple's theories were proven correct in 1986 by close-up photographs
of Haley's comet by the European Space Agency's Giotto spacecraft.

Whipple was born in Red Oak, Iowa, in 1906. He received his bachelor's
degree in mathematics at the University of California, Los Angeles, but
didn't turn to astronomy until a bout with polio ended his dreams of
being a tennis champion.

He completed his doctorate in astronomy at the UC-Berkeley, in 1931 and
accepted a position at Harvard that year.

During World War II, Whipple invented a device used by Allied planes
over Germany to confuse enemy radar. The device cut aluminum foil into
thousands of fragments, giving a false impression of a much larger
number of planes attacking.

In 1946, in anticipation of the future of space flight, Whipple invented
a thin outer skin of metal to protect spacecrafts. Meteors disintegrated
when they hit the shield, known as a meteor bumper or Whipple shield,
leaving only vapor to hit the spacecraft. The technology is still in use
today.

He was also ahead of the curve in 1957, when the Soviet Union launched
the Sputnik satellite. At the time, Whipple was setting up a network of
cameras to track it and one station was already operational.

President Kennedy honored Whipple with an Award for Distinguished Public
Service in 1963 for the project.

Whipple was director of the Smithsonian Astrophysical Observatory in
Cambridge from 1955 to 1973, when it merged with the Harvard Observatory
and was renamed the Harvard-Smithsonian Center for Astrophysics.

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."
Received on Tue 31 Aug 2004 12:07:43 PM PDT