[list_indonesia] [ppiindia] In memoriam: Hans Bethe (98), bapak astrofisika
- From: rahardjo mustadjab <bapakjewel@xxxxxxxxx>
- To: apakabar@xxxxxxxxxxxxxxx, ppiindia@xxxxxxxxxxxxxxx, harisuwasono@xxxxxxxxx, Wisnu Sindhutrisno <sindhutrisno.w@xxxxxxxxxxx>, ade_963@xxxxxxxxx, Kenny Joe <arraniry69@xxxxxxxxxxx>
- Date: Thu, 10 Mar 2005 09:52:59 +0000 (GMT)
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Cerita cukup panjang, harap Anda baca sampai habis.
Yours truly semula menyangka bahwa orang ternama yang
terlibat dalam proyek Manhattan cuma Teller, Julius
Robert Oppenheimer dan Claus Fuchs saja, Ternyata ada
Hans Bethe, yang juga penemu energi luar biasa pada
benda langit berukuran besar seperti matahari kita.
Seperti Oppenheimer, belakangan dia menjadi pendekar
perdamaian anti senjata nuklir. Tapi berlainan dengan
Oppenheimer, dia tidak menyesali perannya dalam
membuat bom atom karena dia yakin perlunya mendahului
Nazi Jerman.
Salam,
RM
--------------------------------------------------------------------------------
March 7, 2005
Hans Bethe, Father of Nuclear Astrophysics, Dies at 98
By WILLIAM J. BROAD
Hans Bethe, who discovered the violent force behind
sunlight, helped devise the atom bomb and eventually
cried out against the military excesses of the cold
war, died late Sunday. He was 98, among the last of
the giants who inaugurated the nuclear age.
His death was announced by Cornell University, where
he worked and taught for 70 years. A spokesman said he
died quietly at home.
Except for the war years at Los Alamos, N.M., Dr.
Bethe lived in Ithaca, N.Y., an unpretentious man of
uncommon gifts. His students called him Hans and
admired his muddy shoes as much as his explaining how
certain kinds of stars shine. For number crunching, in
lieu of calculators, he relied on a slide rule, its
case battered. "For the things I do," he remarked a
few years ago, "it's accurate enough."
For nearly eight decades, Dr. Bethe (pronounced
BAY-tah) pioneered some of the most esoteric realms of
physics and astrophysics, politics and armaments, long
advising the federal government and in time emerging
as the science community's liberal conscience.
During the war, he led the theoreticians who devised
the atom bomb and for decades afterwards fought
against many new arms proposals. His wife, Rose, often
discussed moral questions with him and, by all
accounts, helped him decide what was right and wrong.
Dr. Bethe fled Europe for the United States in the
1930's and quickly became a star of science. As a
physicist, he made discoveries in the world of tiny
particles described by quantum mechanics and the
whorls of time and space envisioned by relativity
theory. He did so into his mid-90's, astonishing
colleagues with his continuing vigor and insight.
In a 1938 paper, Dr. Bethe explained how stars like
the Sun fuse hydrogen into helium, releasing energy
and ultimately light. That work helped establish his
reputation as the father of nuclear astrophysics, and
nearly 30 years later, in 1967, earned him the Nobel
Prize in physics. In all, he published more than 300
scientific and technical papers, many of them
originally classified secret.
Politically, Dr. Bethe was the liberal counterpoint
(and proud of it) to Edward Teller, the physicist and
conservative who played a dominant role in developing
the hydrogen bomb. That weapon brought to earth a more
furious kind of solar fusion, and Dr. Bethe opposed
its development as immoral.
For more than half a century, he championed many forms
of arms control and nuclear disarmament, becoming a
hero of the liberal intelligentsia. His wife called
him a dove, Dr. Bethe once told an interviewer, adding
his own qualifier: "A tough dove." His gentle manner
hid an iron will and mind that had few hesitations
about identifying what he saw as error, hypocrisy or
danger. "His sense of duty toward society is so deeply
ingrained that he isn't even aware of its being a
sacrifice," a close colleague, Dr. Victor F.
Weisskopf, once remarked.
In a 1997 interview in his Cornell office, at age 90,
Dr. Bethe said he had no regrets about his role in
inventing the atom bomb, done amid worries about the
Nazis' getting it first and conquering the world. But
as the most senior of the living scientists who
initiated the atomic age, he urged the United States
to renounce all research on nuclear arms and called on
scientists everywhere to do likewise. His ultimate
dream, he said, his blue eyes calm, was for nations to
cut their nuclear arsenals to a few hundred weapons or
less. "Then," added the survivor of Hitler and
Mussolini, "even if statesmen go crazy again, as they
used to be, the use of these weapons will not destroy
civilization."
Throughout life, he remained a staunch advocate of
nuclear power, defending it as an answer to inevitable
fossil-fuel shortages.
Dr. Bethe was the last of the scientific greats who
initiated the nuclear era, outliving not only Teller
but Enrico Fermi and Robert Oppenheimer, the
scientific head of wartime Los Alamos. "He was one of
Oppenheimer's first recruits," noted Robert S. Norris,
author of "Racing for The Bomb" (Steerforth Press,
2002), "and was among the last survivors of that
extraordinary story."
Mr. Norris added that Dr. Bethe was "the almost
perfect expression" of the scientist-activist, driven
by a sense of responsibility for his own atomic
breakthroughs and those of his physicist colleagues.
"He saw his role as to educate the public and the
policymakers about the new dangers and help figure out
ways to control them," Mr. Norris said.
A biographer, Silvan S. Schweber of Brandeis
University, author of "In the Shadow of the Bomb"
(Princeton, 2000), said he had despaired of mastering
Dr. Bethe's achieve of letters, papers and documents.
Later, he feared that he would need "three fat
volumes" to tell the physicist's story. He described
Dr. Bethe as a moralist who took stands in defense of
universities, democracy and society. What gave him the
courage to do so, he added, was self-confidence, a
strong personality and the support of the community of
friends and scientists he nurtured for nearly seven
decades at Cornell.
Richard Rhodes, who wrote of Dr. Bethe in "The Making
of the Atomic Bomb" (Simon and Schuster, 1986),
remarked on his sunny disposition despite his long
struggle with nuclear dilemmas. "He seemed so calm
and, later in life, so serene," Mr. Rhodes said.
"That's interesting because he, more than any other
leading figure of the Manhattan Project, agonized over
his participation, first in the bomb itself and then
in thermonuclear research" to see if a hydrogen bomb
was possible.
Mary Palevsky, who interviewed Dr. Bethe for a book on
the nuclear age, recalled him as so remarkably
"intellectually open that he was always a pleasure to
talk to." His warmth, his modesty, his integrity, won
the respect of all who knew him, friend and foe alike.
He was not a tragic figure wracked by guilt - the fate
of some who came to regret their bomb labors - but a
man famous for his indefatigable appetite.
His lean body could boom with laughter. He loved to
ski and climb mountains with colleagues. Students
learned to rely on his patience and readiness to help,
be it with research or personal problems. His door,
they found, was always open.
Freeman Dyson, a mathematician at the Institute for
Advanced Study in Princeton who was born in Britain,
recalled meeting Dr. Bethe at Cornell in 1947. "The
thing that impressed me the most," he said, "was that
he had very muddy shoes and all the students called
him Hans. So he was just the opposite of a European
professor. That was part of his greatness. He was
totally unpretentious and never tried to be bigger
than he was." Dr. Bethe, he added, "always had lunch
with the students and had a real concern for the
teaching and all the students he was responsible for.
He had a wonderful gift for finding the right problem
for them, not too difficult and not too easy."
What is perhaps most remarkable about Dr. Bethe is how
his long life embodied a deep faith not in the
ultimate authority of science but of people and the
human spirit - a surprising stance for a man often
viewed as one of the field's high priests. He
understood its limits. His personal philosophy seemed
deceptively simple: science and technology, while good
friends of great importance, cannot save humanity.
Instead, he taught that only humane reasoning and the
struggle to foster just human relationships would keep
civilization from using the accomplishments of science
to destroy itself.
Hans Albrecht Bethe was born on July 2, 1906, in
Strasbourg, Alsace-Lorraine, to a family of modest
means. His father, a physiologist at the University of
Strasbourg, was a Protestant and his mother Jewish. He
was their only child. The frail youth showed an early
genius for mathematics, which his father discouraged,
not wanting his son to get ahead of his peers. The
precocious boy took to secretly reading his father's
books on trigonometry and calculus. Dr. Bethe once
said he grew up in the solace of "numbers and fairy
tales" - things, he added, that a young boy got
interested in when he did not have a little sister to
beat up. The family moved to Frankfurt, where his
father founded a physiology department at the new
university. At the nearby gymnasium, or secondary
school, his son studied Greek and Latin, French and
English, but excelled at math and physics, deciding he
wanted to do both.
His father, meanwhile, became active as a liberal
democrat, running for the city parliament and winning
the young man's admiration. At the University of
Munich, Dr. Bethe studied with Arnold Sommerfeld, one
of the day's leading theoretical physicists. His
teacher bristled with excitement for modern physics,
and the student was soon lost to anything else. In
1928, Dr. Bethe received his doctorate, graduating
summa cum laude, having already made contributions to
the fledgling science of quantum mechanics. The next
year he worked for Paul P. Ewald, a noted physicist in
Stuttgart, and befriended his family, often visiting
and having dinner.
At times, Dr. Bethe took the older Ewald children on
Sunday walks, including Rose, his future wife. After
stints at several universities, he came into conflict
with the new Nazi race laws and fled Germany in 1933.
For two years he taught in England and then came to
Cornell University, in Ithaca, where he remained the
rest of his academic life.
While lecturing at Duke University in 1937, he bumped
into Rose Ewald, who had emigrated and was going to
the school. The two fell in love.
At Cornell, Dr. Bethe wrote a series of brilliant
papers that culminated in the 1938 treatise, "Energy
Production in Stars." It set forth the first and only
explanation of stellar energy that explained all the
known facts - essentially why stars like the Sun burn
for billions of years. His talents were synthetic as
well as analytic, as evidenced by his production of a
wealth of incisive review articles that became
required reading for generations of physicists. Known
as "Bethe's bible," they, like much else he did,
mirrored his precision, thoroughness and extraordinary
powers of concentration
The world - and his world, in particular - changed
forever in 1938, when German scientists discovered
that the atom could be split in two in a burst of
atomic energy, starting quiet deliberations around the
globe into the practicality of chain reactions and a
bomb.
In America, Dr. Bethe discussed the matter with
Teller, another refugee from the Nazis. The two were
close friends. In New Rochelle, N.Y., the Hungarian
physicist was one of the few guests invited when Dr.
Bethe and Rose got married in September 1939. In
addition to his wife, Dr. Bethe is survived by two
children, Henry, of Ithaca, and Monica, who lives near
Kyoto, Japan, and three grandchildren.
Dr. Bethe's reputation grew with the war effort. In
1940, Time magazine called him "one of Nazi Germany's
greatest gifts to the United States." He was helping
advance radar at the Massachusetts Institute of
Technology when an atomic recruiter came to call,
meeting him conspiratorially in the Harvard Yard. In
1942, during a walk in the mountains of Yosemite, his
wife asked him "to consider carefully" if he wanted to
continue assessing the feasibility of nuclear arms,
Dr. Bethe told Jeremy Bernstein, author of "Hans
Bethe, Prophet of Energy" (Basic Books, 1979).
Worried that Nazi Germany wanted such weapons, he
decided that he did. In 1943, he was named the first
director of the theoretical division at Los Alamos,
the secret laboratory in the mountains of New Mexico
where thousands of scientists, technicians and
military personnel were gathering to see if a nuclear
bomb was indeed possible. Behind rows of barbed wire,
he coaxed some of world's brightest and most
idiosyncratic experts to work hard on how to unlock
the atom. In typical fashion, he bore down on the
problems like a battleship, studying them carefully
and then crushing them. Colleagues often balked. "No,
no, you're crazy!" Dr. Richard Feynman, a young
scientist who eventually gained fame as an eccentric
genius, protested one day. But Dr. Bethe plowed ahead,
proving his idea exactly right. At Los Alamos, Dr.
Bethe's group calculated such things as how much
plutonium it would take to build an atom bomb, and
whether the detonation would ignite the atmosphere and
destroy the earth.
The bomb's horrors became a turning point for Dr.
Bethe. After the destruction of Hiroshima and
Nagasaki, he devoted himself to trying to stop the
weapon's "own impulse," as he put it. While retaining
links to the government and Los Alamos, he helped lead
the corps of atomic scientists who, in an
unprecedented wave, left secluded laboratories to
plead before Congress and the American public for
nuclear restraint.
He also plunged back into academic life at Cornell,
educating a new generation of physicists. He recruited
Dr. Feynman, his Los Alamos protégé, and helped him
develop quantum electrodynamics, an advanced theory
for which Dr. Feynman eventually shared the Nobel
Prize.
In April 1950, Dr. Bethe wrote a provocative article
in Scientific American arguing against development of
the hydrogen bomb, an advance then looming. He had
concluded, after discussions with his wife and
colleagues, that it had little military use and was
primarily a weapon for incinerating civilians in large
cities. "We must save humanity from this ultimate
disaster," he wrote. "And we must break the habit,
which seems to have taken hold of this nation, of
considering every weapon as just another piece of
machinery and a fair means to win our struggle with
the U.S.S.R."
By contrast, Teller lobbied hard for the superbomb, as
it was called. Dr. Bethe worked on it too, hoping to
prove the idea impossible and considering his work a
hedge against the possibility that the Soviets might
get it first. In 1952, a blinding flash of light
marked the detonation of the world's first hydrogen
bomb, its power roughly one thousand times greater
than the weapon that destroyed Hiroshima. During the
cold war, Dr. Bethe and Teller went from increasingly
cool friends to bitter foes. The denouement came in
1954 - at the height of the McCarthy era - over the
government's push to remove the security clearance of
Oppenheimer, then the top scientific adviser to the
Atomic Energy Commission and a man who probably held
more nuclear secrets in his head than any other
American.
One charge was that Oppenheimer had argued against a
crash program for H-bomb development. Another was that
he had Communist ties. In Washington, Dr. Bethe and
his wife spent an evening trying to persuade Teller to
testify in favor of Oppenheimer - to no avail. At a
secret hearing, Dr. Bethe defended his former boss and
Teller strongly faulted Oppenheimer's judgment. The
clearance was eventually revoked, and Oppenheimer
quickly fell from power.
Afterward, Dr. Bethe wrote a long article charging
that Teller, not Oppenheimer, had hindered the
nation's pursuit of the superbomb for years due to a
series of mathematical errors. It was only after the
size of Teller's mistakes became apparent, Dr. Bethe
wrote, that Teller and his colleagues were forced to
find the right way to go about solving the problem.
The article, written in 1954, was quickly stamped top
secret and only declassified three decades later.
Despite his fears of an unfettered arms race, Dr.
Bethe continued to consult for the government and on
occasion to help make weapons. In 1955, he perfected a
general theory of ablation that was applied to the
construction of warheads that could withstand the
searing heat of re-entry through the earth's
atmosphere. His idea helped beget the intercontinental
ballistic missile. Increasingly, he also sought ways
to slow the nuclear arms race, winning new influence
for his ideas in Washington. As a member of the
President's Science Advisory Committee, starting in
1956, he became a driving force behind the world's
first and most successful arms control pact - the 1963
Limited Test Ban Treaty, which confined nuclear tests
to beneath the earth.
In usual fashion, Teller fought it all the way. Dr.
Bethe saw the treaty as a bold step toward disarmament
and a way to end the rain of radioactive fallout that
had increased people's risk of cancer and birth
defects. "Very good. Very right," he remarked on the
occasion of its signing, visibly moved. His influence
soaring, in 1967 Dr. Bethe was awarded the Nobel Prize
for his explanation of how the stars shine.
A 1968 profile by the journalist Lee Edison described
Dr. Bethe as "a tall, spare man with a deceptively
distracted look." He wrote: "His graying hair seems
permanently electrified; his shoes are scuffed, and
his tie seems to have been studiously arranged to miss
his collar button. He listens attentively, nodding his
head as if in agreement, but - as devastated
colleagues and adversaries have discovered - this
habit is far from a sign of agreement. His 'yes, yes,
yes' is rather a signal that his mental apparatus is
receiving. What he does with the input is another
matter."
In the late 1960's and early 1970's Dr. Bethe lent his
growing prestige to fight the government's plans to
deploy antimissile weapons. Having studied the issue
for President Dwight D. Eisenhower, he was convinced
that all such systems could be easily defeated. It was
just too easy, he held, for an adversary to make
decoys and other countermeasures that offensive
missiles would jettison to outwit defensive arms. And
while militarily futile, he argued, antimissile arms
would succeed extremely well at adding costly new
spirals to the arms race as each side struggled for
advantage. Like before, Dr. Bethe found himself
strongly opposed by Teller, who this time wanted to
shield America from the hydrogen bombs that
adversaries had learned how to make. In 1975, at a
cost of some $6 billion, the government switched on a
limited antimissile system that was soon abandoned
because of its ineffectiveness.
In the 1970's, after the Arab oil embargo started a
global economic crisis, Dr. Bethe threw himself into
championing new ways to produce energy. In articles,
speeches and Congressional hearings, he argued that
the dangers of nuclear reactors were small compared
with many other risks judged to be socially
acceptable. During this period, Dr. Bethe and Teller,
both firm advocates of nuclear power, became somewhat
closer, "although not with the intimacy of the old
days," Dr. Bethe recalled.
He formally retired from Cornell in the summer of
1975. But that did little to slow his activity. In the
1980's, with the arrival of the Reagan administration,
Dr. Bethe again found himself the elder spokesman of
scientists opposed to unfettered development of
nuclear arms. And his relations with Teller again
began to cool. The Pentagon, he said in an article,
"proposes to address all threats - real and imagined -
by raising the ante," adding, "It refuses to recognize
that our worst nightmares can be laid to rest only by
constraints on technology."
With passion, he fought President Reagan's proposed
shield against enemy missiles, known popularly as
"Star Wars." It again pitted him against Teller in
what would be their last battle. In February 1983,
Teller tried to win over Dr. Bethe by revealing the
secret details of what he considered the ultimate
technical fix - the X-ray laser, powered by a nuclear
bomb. It would emit powerful beams to smash Soviet
warheads before consuming itself in a ball of nuclear
fire, an H-bomb to destroy H-bombs.
"You have a splendid idea," Dr. Bethe said,
complimenting Teller on its physics. But he soon led
opposition to the X-ray laser, arguing that an enemy
could easily outwit the exotic weapon. "We need to try
to understand the other fellow and negotiate and try
to come to some agreement about the common danger,"
Dr. Bethe said after his Teller meeting. "That is
what's been forgotten. The solution can only be
political. It would be terribly comfortable for the
president and the secretary of defense if there was a
technical solution. But there isn't any."
Ultimately, the government sided with Dr. Bethe,
foregoing antimissile deployments in the 1980's and
1990's, a decision the Bush administration has now
reversed. In his memoirs, Teller accused Dr. Bethe of
letting his political views color his technical
judgment.
Throughout the political activism that marked his
later life, Dr. Bethe never abandoned his first love -
science. With what might be seen as poetic finesse, he
turned his attention to the question of why old stars
can suddenly explode with the brilliance of an entire
galaxy. An average star like the sun dies quietly. But
larger ones can die violently, though no one is quite
sure why. "They go on a rampage," Dr. Bethe said with
a smile, the blackboard behind him filled with
equations. "In a year they emit as much energy as the
sun does in 10 billion years of history. Why does this
happen?" At the start, he said, the central part of a
star exhausts its fuel supply, collapsing so fast that
the outside of the star stays uninvolved. The small
core then bounces back. "The question we are
studying," he continued, "is whether that shock wave
is strong enough to go all the way through the star
and to expel essentially all its outside, because that
is what is observed in supernovas."
In 1995, many of Dr. Bethe's colleagues gathered to
hail his 60th year at Cornell with a two-day tribute.
"If you know his work," commented John Bahcall, an
astrophysicist at the Institute for Advanced Study,
"you might be inclined to think he is really several
people, all of whom are engaged in a conspiracy to
sign their work with the same name." Alan Lightman, a
physicist and author at the Massachusetts Institute of
Technology, recalled attending a meeting with Dr.
Bethe in October 1997, after the celebrated physicist
had turned 91. He expected reminiscences. But Dr.
Bethe, after tottering up to the podium, surprised
him. "It was a paper on astrophysics that he had just
published," Dr. Lightman recalled. "And it was good."
Dr. Schweber of Brandeis University, a physicist and
historian, said Dr. Bethe achieved a life of
professional and personal fulfillment because he
learned the redemptive power of love, of serving
family and friends, students and society.
Dr. Bethe's élan seemed to confirm that judgment. "I
am a very happy person," he said with a relaxed smile
a few years ago. "I wouldn't want to change what I
did."
The New York Times
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