March 12, 2002
SCIENTIST AT WORK / JOHN ARCHIBALD WHEELER
Peering Through the Gates of Time
By DENNIS OVERBYE
Don Standing for The New York Times
In his Princeton office, Dr. John Wheeler, 90, touches up a vision of cosmic uncertainty.
PRINCETON, N.J., March 5 — It's all come down to this.
In one corner is Dr. John Archibald Wheeler, 90, professor emeritus of physics at Princeton and the University of Texas, armed with a battery of hearing aids, fistfuls of colored chalk, unfailing courtesy, a poet's flair for metaphor, an indomitable sense of duty and the company of a ghost army of great thinkers.
In the other is a "great smoky dragon," which is how Dr. Wheeler refers sometimes to one of the supreme mysteries of nature. That is the ability, according to the quantum mechanic laws that govern subatomic affairs, of a particle like an electron to exist in a murky state of possibility — to be anywhere, everywhere or nowhere at all — until clicked into substantiality by a laboratory detector or an eyeball.
Dr. Wheeler suspects that this quantum uncertainty, as it is more commonly known, is the key to understanding why anything exists at all, how something, the universe with its laws, can come from nothing. Or as he likes to put it in the phrase that he has adopted as his mantra: "How come the quantum? How come existence?"
Standing by the window in his third-floor office in Princeton's Jadwin Hall recently, Dr. Wheeler pointed out at the budding trees and the green domes of the astronomy building in the distance. "We're all hypnotized into thinking there's something out there," he said.
Twice a week he takes a bus from his retirement home in nearby Hightstown to sit here under portraits of Albert Einstein and Niels Bohr, the twin poles of his scientific life, and confront the dragonlike ephemerality of the world, dictating his thoughts to his secretary, Emily Bennett.
"The time left for me on earth is limited," he wrote recently. "And the creation question is so formidable that I can hardly hope to answer it in the time left to me. But each Tuesday and Thursday I will put down the best response that I can, imagining that I am under torture."
He is under no illusions about who will win the confrontation. A heart attack last year has taken its toll, and he acknowledges that his thoughts are fragmentary, ideas for ideas, as he likes to put it, and not for his present-day colleagues but for the generations of colleagues down the line.
It's what he has been doing his whole life. Dr. Wheeler helped explain nuclear fission with Bohr, argued quantum theory with Einstein, helped build the atomic and hydrogen bombs and pioneered the study of what he later dubbed black holes. Along the way, he indulged his taste for fireworks and mischief and became the hippest poet physicist of his generation, using metaphor as effectively as calculus to capture the imaginations of his students and colleagues and to send them, minds blazing, to the barricades to confront nature.
The phrases Dr. Wheeler has coined constitute a kind of vapor trail marking the path of the aspirations of physics in the last few decades: black hole, quantum foam, law without law, to name a few.
"A major piece of him is that he is a visionary," said Dr. Kip Thorne, a physics professor at California Institute of Technology who was Dr. Wheeler's graduate student at Princeton. "He tries to see farther over the horizon than most people by way of his physical intuition."
"He brought the fun back into physics," said Dr. Max Tegmark, a cosmologist at the University of Pennsylvania who has recently collaborated with Dr. Wheeler, ticking off the reasons scientists love him. Physicists, he said, are usually reluctant to talk about Really Big Questions, like the why of existence, for fear of being branded flaky.
"He taught us not to be afraid," Dr. Tegmark said.
It is a season of celebration for Dr. Wheeler and of reaping the harvest from generations of seeds of inspiration. The Battelle Memorial Institution of Columbus, Ohio, has donated $3 million to endow a physics chair in Dr. Wheeler's name at Princeton, which celebrated his birthday with one-day symposium last July, and plans a larger event.
On March 15, the Really Big Questions that Dr. Wheeler loves will be on the table when prominent scientists gather at a conference center here in his honor for a symposium modestly titled "Science and Ultimate Reality" sponsored by the John Templeton Foundation and the Peter Gruber Foundation Cosmology Prize.
The Philosopher King
Leave Indelible Mark
Dr. Wheeler once compared himself to Daniel Boone, who, the story goes, felt compelled to move on to new territory every time someone moved within a mile of him. It was in nuclear physics, the science of the buzzing dense cores of atoms, that he first made his mark. Born July 9, 1911, in Jacksonville, Fla., the oldest child in a family of librarians, he earned his Ph.D. in physics from Johns Hopkins at age 21.
A year later, after becoming engaged to an old acquaintance, Janette Hegner, after only three dates — they have been married 67 years and have three children, eight grandchildren and nine great-grandchildren — Dr. Wheeler took a boat to Copenhagen. There, Bohr was presiding over a small research institute and serving as the philosopher king of a revolution that had shaken physics and common sense to the marrow in the previous decade.
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 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, a smoky dragon. In some sense no particle or other phenomenon was real, Bohr said, until it was an observed phenomenon.
The year spent in Copenhagen watching Bohr wrestle with the paradoxes of the quantum world was the beginning of a lifelong relationship that left an indelible mark.
"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 later said.
In January 1939 when Bohr arrived for a visit in the United States, Dr. Wheeler, a young Princeton professor, met the boat.
Within a few weeks the two had sketched out a theory of how nuclear fission, recently discovered in Germany, worked. In their model the nucleus is like a liquid drop that starts vibrating when a neutron hits it, elongating into a peanut shape that then snaps in two, shooting out energy and particles.
(Page 2 of 2)
Dr. Wheeler was later swept up in the Manhattan Project to build an atomic bomb. But he still blames himself for a two-year delay between the time in 1939 that Einstein wrote a letter urging President Franklin D. Roosevelt to start a bomb project and when it got going. Had the war ended two years earlier, he says, millions of lives might have been saved, including that of a younger brother, Joe, who died fighting in Italy, but knew enough about what was going on in physics to have sent his older brother a card in 1944, saying simply, "Hurry up!"
Dr. Wheeler interrupted a sabbatical in Paris in 1950 to come back to the United States and help Dr. Edward Teller develop a hydrogen bomb. For his pains Dr. Wheeler was once officially reprimanded by President Dwight D. Eisenhower for losing a classified document on a train, but he was later honored by President Lyndon B. Johnson in a White House ceremony.
Gates of Time
Of Cosmic Dead End
Back in academia, Dr. Wheeler found himself being lured away from nuclear physics by the theories of another Princeton resident, Einstein. The two occasionally talked about quantum theory, which Einstein found abhorrently random, but what intrigued Dr. Wheeler was Einstein's theory of relativity.
Gravity, according to Einstein's vision, was just the geometry of space-time, warped or "curved" in the presence of matter or energy, the way a mattress sags under a hefty sleeper.
The part that interested Dr. Wheeler most was an apocalyptic prediction contained within the equations: matter, say in a dead star, could collapse into a heap so dense that light could not even escape from it, eventually squeezing itself out of existence. At the center, space would be infinitely curved, and as Dr. Wheeler likes to say, "smoke pours out of the computer." Space, time and even the laws of physics themselves would break down at this cosmic dead end, called a singularity.
Dr. Wheeler made it his mission to alert the rest of his colleagues to the paradoxical vision of physics predicting its own demise. Dr. Wheeler made Princeton the center of research in general relativity, a field that had been moribund because of its remoteness from laboratory experiment, in the United States.
"He rejuvenated general relativity," said Dr. Freeman Dyson, a theorist at the Institute for Advanced Study, across town in Princeton.
It was not until 1967, at a conference in New York City, that Dr. Wheeler, adopting a suggestion shouted from the audience, hit upon 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 later said in his 1998 autobiography, "Geons, Black Holes & Quantum Foam: A Life in Physics," written with Dr. Kenneth Ford, a former student and the retired director of the American Institute of Physics.
Moreover, Dr. Wheeler preached, the breakdown of physics could not be sealed away in a distant dead star. He pointed out that even space and time had to pay their dues to the uncertainty principle. When viewed on very small scales or in the compressed throes of the Big Bang, what looked so smooth and continuous, like an ocean from an airplane, would become discontinuous, dissolving like a dry sand castle into a mess of unconnected points and worm holes that Dr. Wheeler dubbed "quantum foam."
In a sense, black holes, or "gates of time," as he later called them, were everywhere, under our fingernails, courtesy of the uncertainty principle, and thus so was the issue of where the laws of physics came from.
By the 1970's Dr. Wheeler was ready to move on. Faced with mandatory retirement from teaching at Princeton, he moved to the University of Texas, where he turned to the very small, that is to say, the quantum, with the energy and eloquence that he had once lavished on black holes.
"Relativity is exciting but it's not surprising, it's not peculiar," he once told Dr. Ford. "Quantum theory remains a mystery; it's a greater challenge for the 21st century."
One idea that he and his Texas colleagues investigated was the notion that the universe is a giant computer and that quantum theory can somehow be derived from information theory, the logic of bits and bytes.
The work goes on, and will be one of the main items of discussion in Princeton this weekend.
It From Bit
Are Set in Stone
Told that he had to slow down after bypass surgery, Dr. Wheeler moved to a retirement home near Princeton in 1986.
On his way to lunch recently Dr. Wheeler took a visitor on a detour through the old brick building once known as Fine Hall, now Jones Hall, pointing out the offices that he, Einstein and Bohr had occupied in 1939.
Across the hall was a lounge with rows of windows, leather couches and a fireplace with an inscription from Einstein on the mantelpiece. "Raffiniert ist der Herr Gott, aber Boshaft ist er nicht," Dr. Wheeler said, reading. Then he translated, roughly, "God is clever, but he's not malicious."
Asked if he agreed, Dr. Wheeler nodded, then pumped his fist in affirmation.
Back in his office Dr. Wheeler busied himself at the blackboard with a diagram that is emblematic of quantum weirdness, and of his hope for constructing the universe and its laws "higgledy-piggledy," as he likes to call it, out of nothing.
It is called double slit experiment. In it an electron or any other particle flies toward a screen with a pair of slits. Past the screen is a physicist with a choice of two experiments. One will show that the electron was a particle and passed through one or another slit; the other will show that it was a wave and passed through both slits, producing an interference pattern. The electron will turn out to be one or the other depending on the experimenter's choice.
That was weird enough, but in 1978 Dr. Wheeler pointed out that the experimenter could wait until after the electron would have passed the slits before deciding which detector to employ and thus whether it had been a particle or wave. In effect, in this "delayed choice" experiment, the physicists would be participating in creating the past.
In a 1993 paper Dr. Wheeler likened such a particle to a "great smoky dragon," whose tail was at the entrance slits of the chamber and its teeth at the detector, but in between — before it had been "registered" in some detector as a phenomenon — was just a cloud, smoky probability.
Perhaps the past itself is such a smoky dragon awaiting our perception.
He wonders if the delayed choice experiment is a prescription for how the universe can be built up from information, as in a cosmic game of 20 questions, a series of yes-no decisions resulting from billions upon billions of quantum observations. It's a concept that has gone by many names over the last few decades from "genesis by observership" to "participatory universe" to the current fashion, "it from bit."
Typically there is a diagram, a cartoon actually, which consists of a giant U with an eyeball on top of one stem looking back at the other. The skinny unadorned end of the U is the Big Bang, he explained, tracing his finger along the loop.
"The model of the universe starts out all skinny and then gets bigger," he said. "Finally it gives rise to life and the mind and the power to observe, and by the act of observation of those first days, we give reality to those first days."
An excerpt dated Jan. 29, 2002, from Dr. Wheeler's journal reads: "No space, no time, no gravity, no electromagnetism, no particles. Nothing. We are back where Plato, Aristotle and Parmenides struggled with the great questions: How Come the Universe, How Come Us, How Come Anything? But happily also we have around the answer to these questions. That's us."
It's a gaudy notion even for an adventurer like Dr. Wheeler.
But as Dr. Thorne pointed out, Dr. Wheeler's track record with crazy ideas is surprisingly good. One such idea had led to a Nobel Prize for Dr. Wheeler's graduate student Dr. Richard Feynman, the noted Caltech physicist. Dr. Thorne recalled Dr. Feynman's telling him once, "Some people think Wheeler's gotten crazy in his later years, but he's always been crazy."