2016年2月15日 星期一

John A. Wheeler, ‘Black Hole, ’"黑洞之父"約翰﹒惠勒


Ben Chen
4小時Amazon
1973年,長年在普林斯頓的,John Wheeler 和兩位學生推出了代表作,厚達千頁的《Gravitation》,使愛因斯坦的廣義相對論的研究,在物理學界又熱門起來。可以說是愛因斯坦重力理論最最重要的傳𠄘者。
Wheeler創造了"black hole"一詞,有許多超乎尋常近乎玄學的思維。可以説是物理學界的哲人或預言家、"玄學家".
Wheeler兩位重要徒弟:
1: Richard Feynman
以及
2: 在重力理論有成就的
Kip Thorne,指出兩個黑洞對撞合一,其產生的能量是全宇宙所有星球輻射能量加起來的一萬倍!!!
是僅次於Big Bang的能量。如此能量的重力波,才使此次的LIGO成為可能。
Thorne is a co-founder (with Weiss and Drever) of the LIGO Project and he chaired the steering committee that led LIGO in its earliest years (1984--87).
In the 1980s, 90s and 2000s he and his research group have provided theoretical support for LIGO, including identifying gravitational wave sources that LIGO should target, laying foundations for data analysis techniques ---
LIGO的成果,應該可以說是他一生最大的學術成就了。
以下是Dyson對Wheeler的推崇:
John Wheeler] rejuvenated general relativity; he made it an experimental subject and took it away from the mathematicians
— Freeman Dyson
The poetic Wheeler is a prophet, standing like Moses on the top of Mount Pisgah, looking out over the promised land that his people will one day inherit.
-Freeman Dyson
This landmark text offers a rigorous full-year graduate level course on gravitation physics, teaching students to:• Grasp the laws of physics in flat spacetime• Predict orders of magnitude• Calculate using the principal tools…
WWW.AMAZON.COM


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惠勒自傳:物理歷史與未來的見證者, 2000, 惠勒/福特/蔡承志/Wheeler, John A/Ford, Kenneth, 台北:商周出版,

國普林斯頓大學物理學家惠勒John Wheeler)所說的:「一切事物都由位元資訊衍生而來。」 對於所有事物的運算法則來說,黑洞似乎是個例外。

"黑洞之父"約翰﹒惠勒去世

威爾勒博士(普林斯頓大學網站)
威爾勒博士在學界享有極高的聲望

首先以"黑洞"形容天體收縮現象的約翰﹒惠勒博士去世,享年96歲。他也曾經參加了二戰期間製造原子彈的"曼哈頓計劃"。
美國物理學界形容惠勒博士是學界巨人、學界的超級英雄。
這也反映了約翰﹒惠勒一生對學界所作的非凡貢獻。
約翰﹒惠勒曾經與愛因斯坦合作,並且試圖在愛因斯坦過世之後,完成愛因斯坦的理論。
約翰﹒惠勒還是研究核融合的先鋒,後來加入了"曼哈頓計劃"、製造出了世界第一枚原子彈。
美國總統布什形容約翰﹒惠勒是參與了一個"改變歷史"的計劃。
他和一些隨後後悔參與原子彈發展計劃的科學家不同。約翰﹒惠勒遺憾的是沒有及早完成原子彈,從而得以提前結束二戰歐洲的戰事。
惠勒生前時常提到沒能早點造出原子彈,所以他的弟弟才會在1944年戰死在歐洲。

黑洞
黑洞來自於一個學生的建議

不凡的一生
約翰﹒惠勒戰後在美國普林斯頓大學任教並且研究天體物理。
到他94歲那年,都還在普林斯頓大學保留著一間辦公室。
他教學手法靈活,時常鼓勵學生在學習過程當中扮演積極的角色。
有一次在課堂上,他問學生如何以一個詞來形容星球塌縮、密度緊密到無法透光的現象。
一名學生舉手回應說"黑洞!"。惠勒博士隨後把這個詞大加推廣,如今是連小學生也聽過"黑洞"這個詞。
他的同事說,約翰﹒惠勒非常瞭解把複雜的理論變得通俗易懂有多麼重要。

John A. Wheeler, Physicist Who Coined the Term ‘Black Hole,’ Is Dead at 96


The New York Times
John A. Wheeler at Princeton University in 1967.


Published: April 14, 2008

John A. Wheeler, a visionary physicist and teacher who helped invent the theory of nuclear fission, gave black holes their name and argued about the nature of reality with Albert Einstein and Niels Bohr, died Sunday morning at his home in Hightstown, N.J. He was 96.

The cause was pneumonia, said his daughter Alison Wheeler Lahnston.
Dr. Wheeler was a young, impressionable professor in 1939 when Bohr, the Danish physicist and his mentor, arrived in the United States aboard a ship from Denmark and confided to him that German scientists had succeeded in splitting uranium atoms. Within a few weeks, he and Bohr had sketched out a theory of how nuclear fission worked. Bohr had intended to spend the time arguing with Einstein about quantum theory, but “he spent more time talking to me than to Einstein,” Dr. Wheeler later recalled.
As a professor at Princeton and then at the University of Texas in Austin, Dr. Wheeler set the agenda for generations of theoretical physicists, using metaphor as effectively as calculus to capture the imaginations of his students and colleagues and to pose questions that would send them, minds blazing, to the barricades to confront nature.
Max Tegmark, a cosmologist at the Massachusetts Institute of Technology, said of Dr. Wheeler, “For me, he was the last Titan, the only physics superhero still standing.”
Under his leadership, Princeton became the leading American center of research into Einsteinian gravity, known as the general theory of relativity — a field that had been moribund because of its remoteness from laboratory experiment.
“He rejuvenated general relativity; he made it an experimental subject and took it away from the mathematicians,” said Freeman Dyson, a theorist at the Institute for Advanced Study across town in Princeton.
Among Dr. Wheeler’s students was Richard Feynman of the California Institute of Technology, who parlayed a crazy-sounding suggestion by Dr. Wheeler into work that led to a Nobel Prize. Another was Hugh Everett, whose Ph.D. thesis under Dr. Wheeler on quantum mechanics envisioned parallel alternate universes endlessly branching and splitting apart — a notion that Dr. Wheeler called “Many Worlds” and which has become a favorite of many cosmologists as well as science fiction writers.
Recalling his student days, Dr. Feynman once said, “Some people think Wheeler’s gotten crazy in his later years, but he’s always been crazy.”
John Archibald Wheeler — he was Johnny Wheeler to friends and fellow scientists — was born on July 9, 1911, in Jacksonville, Fla. The oldest child in a family of librarians, he earned his Ph.D. in physics from Johns Hopkins University at 21. A year later, after becoming engaged to an old acquaintance, Janette Hegner, after only three dates, he sailed to Copenhagen to work with Bohr, the godfather of the quantum revolution, which had shaken modern science with paradoxical statements about the nature of reality.
“You can talk about people like Buddha, Jesus, Moses, Confucius, but the thing that convinced me that such people existed were the conversations with Bohr,” Dr. Wheeler said.
Their relationship was renewed when Bohr arrived in 1939 with the ominous news of nuclear fission. In the model he and Dr. Wheeler developed to explain it, the atomic nucleus, containing protons and neutrons, is like a drop of liquid. When a neutron emitted from another disintegrating nucleus hits it, this “liquid drop” starts vibrating and elongates into a peanut shape that eventually snaps in two.
Two years later, Dr. Wheeler was swept up in the Manhattan Project to build an atomic bomb. To his lasting regret, the bomb was not ready in time to change the course of the war in Europe and possibly save his brother Joe, who died in combat in Italy in 1944.
Dr. Wheeler continued to do government work after the war, interrupting his research to help develop the hydrogen bomb, promote the building of fallout shelters and support the Vietnam War and missile defense, even as his views ran counter to those of his more liberal colleagues.
Dr. Wheeler was once officially reprimanded by President Dwight D. Eisenhower for losing a classified document on a train, but he also received the Atomic Energy Commission’s Enrico Fermi Award from President Lyndon B. Johnson in 1968.
When Dr. Wheeler received permission in 1952 to teach a course on Einsteinian gravity, it was not considered an acceptable field to study. But in promoting general relativity, he helped transform the subject in the 1960s, at a time when Dennis Sciama, at Cambridge University in England, and Yakov Borisovich Zeldovich, at Moscow State University, founded groups that spawned a new generation of gravitational theorists and cosmologists.
One particular aspect of Einstein’s theory got Dr. Wheeler’s attention. In 1939, J. Robert Oppenheimer, who would later be a leader in the Manhattan Project, and a student, Hartland Snyder, suggested that Einstein’s equations had made an apocalyptic prediction. A dead star of sufficient mass could collapse into a heap so dense that light could not even escape from it. The star would collapse forever while spacetime wrapped around it like a dark cloak. At the center, space would be infinitely curved and matter infinitely dense, an apparent absurdity known as a singularity.
Dr. Wheeler at first resisted this conclusion, leading to a confrontation with Dr. Oppenheimer at a conference in Belgium in 1958, in which Dr. Wheeler said that the collapse theory “does not give an acceptable answer” to the fate of matter in such a star. “He was trying to fight against the idea that the laws of physics could lead to a singularity,” Dr. Charles Misner, a professor at the University of Maryland and a former student, said. In short, how could physics lead to a violation itself — to no physics?
Dr. Wheeler and others were finally brought around when David Finkelstein, now an emeritus professor at Georgia Tech, developed mathematical techniques that could treat both the inside and the outside of the collapsing star.
At a conference in New York in 1967, Dr. Wheeler, seizing on a suggestion shouted from the audience, hit on the name “black hole” to dramatize this dire possibility for a star and for physics.
The black hole “teaches us that space can be crumpled like a piece of paper into an infinitesimal dot, that time can be extinguished like a blown-out flame, and that the laws of physics that we regard as ‘sacred,’ as immutable, are anything but,” he wrote in his 1999 autobiography, “Geons, Black Holes & Quantum Foam: A Life in Physics.” (Its co-author is Kenneth Ford, a former student and a retired director of the American Institute of Physics.)
In 1973, Dr. Wheeler and two former students, Dr. Misner and Kip Thorne, of the California Institute of Technology, published “Gravitation,” a 1,279-page book whose witty style and accessibility — it is chockablock with sidebars and personality sketches of physicists — belies its heft and weighty subject. It has never been out of print.
In the summers, Dr. Wheeler would retire with his extended family to a compound on High Island, Me., to indulge his taste for fireworks by shooting beer cans out of an old cannon.
He and Janette were married in 1935. She died in October 2007 at 99. Dr. Wheeler is survived by their three children, Ms. Lahnston and Letitia Wheeler Ufford, both of Princeton; James English Wheeler of Ardmore, Pa.; 8 grandchildren, 16 great-grandchildren, 6 step-grandchildren and 11 step-great-grandchildren.
In 1976, faced with mandatory retirement at Princeton, Dr. Wheeler moved to the University of Texas.
At the same time, he returned to the questions that had animated Einstein and Bohr, about the nature of reality as revealed by the strange laws of quantum mechanics. The cornerstone of that revolution was the uncertainty principle, propounded by Werner Heisenberg in 1927, which seemed to put fundamental limits on what could be known about nature, declaring, for example, that it was impossible, even in theory, to know both the velocity and the position of a subatomic particle. Knowing one destroyed the ability to measure the other. As a result, until observed, subatomic particles and events existed in a sort of cloud of possibility that Dr. Wheeler sometimes referred to as “a smoky dragon.”
This kind of thinking frustrated Einstein, who once asked Dr. Wheeler if the Moon was still there when nobody looked at it.
But Dr. Wheeler wondered if this quantum uncertainty somehow applied to the universe and its whole history, whether it was the key to understanding why anything exists at all.
“We are no longer satisfied with insights only into particles, or fields of force, or geometry, or even space and time,” Dr. Wheeler wrote in 1981. “Today we demand of physics some understanding of existence itself.”
At a 90th birthday celebration in 2003, Dr. Dyson said that Dr. Wheeler was part prosaic calculator, a “master craftsman,” who decoded nuclear fission, and part poet. “The poetic Wheeler is a prophet,” he said, “standing like Moses on the top of Mount Pisgah, looking out over the promised land that his people will one day inherit.” Wojciech Zurek, a quantum theorist at Los Alamos National Laboratory, said that Dr. Wheeler’s most durable influence might be the students he had “brought up.” He wrote in an e-mail message, “I know I was transformed as a scientist by him — not just by listening to him in the classroom, or by his physics idea: I think even more important was his confidence in me.”
Dr. Wheeler described his own view of his role to an interviewer 25 years ago.
“If there’s one thing in physics I feel more responsible for than any other, it’s this perception of how everything fits together,” he said. “I like to think of myself as having a sense of judgment. I’m willing to go anywhere, talk to anybody, ask any question that will make headway.
“I confess to being an optimist about things, especially about someday being able to understand how things are put together. So many young people are forced to specialize in one line or another that a young person can’t afford to try and cover this waterfront — only an old fogy who can afford to make a fool of himself.
“If I don’t, who will?”

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