St. John’s College Speaker Series - Dr. Brian Greene

Roll Over, Einstein:
"Strings" May Reveal Origins of Universe, Physicist Declares at St. John’s Lecture

Sure, Albert Einstein offered revolutionary ideas to help lesser mortals grasp how the universe works.

But even Einstein fell short of the prize scientists have sought for centuries - namely, an elegant, convincing theory for the origins of reality itself.

"The big issues haven’t been fully addressed by any means," declared renowned physicist Brian Greene on Monday, April 3, before an audience of nearly 200 students, alumni and faculty at St. John's University.

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"Though Einstein undeniably had a dramatic impact on the way we think about things," he added, "one goal eluded him - finding a ‘unified theory’ of the universe."

Today, Dr. Greene said, that theory may be closer than ever, thanks to a mysterious substance physicists call "strings" - tiny particles of vibrating energy. Their worm-like wriggling in the fabric of reality may be the key to questions that stumped Einstein, Newton and other giants of physics.

"These are lofty questions," Dr. Greene noted. "What is space? What is time? What are the basic ‘entities’ that make up the ‘stuff’ in the world around us? And what are the laws by which those entities . . . drive the evolution of the cosmos?"

A "Cutting-Edge" Idea
Combining video clips, a disarming sense of humility and frequent bursts of humor, Dr. Greene held the audience as he explored these issues in "Explaining the Elegant Universe," the lecture he delivered in Marillac Auditorium on St. John’s Queens campus.

The presentation was part of a new lecture series sponsored by St. John’s College of Liberal Arts and Sciences.

A professor of physics and mathematics at Columbia University, Dr. Greene is one of the world’s leading proponents of "Superstring Theory" - an attempt to find the "Theory of Everything" that eluded Einstein.

"You have to bear in mind," he said, "that this is not a ‘theory’ in a traditional sense. These are cutting edge ideas, not yet tested by the experimental community."

What are superstrings? They are, Dr. Greene proposed, the tiny particles we would find if we could slice open electrons or quarks. These "infinitesimally small filaments" vibrate "like the strings of a violin or cello." The vibrations create something far different from sound.

"Strings do not produce music," Dr. Green explained. "They produce particles. When a ‘string’ vibrates in one pattern, it forms an electron. When it vibrates in another pattern, it forms a quark."

Dr. Greene readily admitted that no one has ever observed superstrings. "They’re too darned small," he said. But, he added, the concept is "sufficiently rich and compelling that it’s worth the journey, worth thinking about them and reaching some conclusion in the not-too-distant future."

Dr. Greene based the lecture on his New York Times-bestselling book, "The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory" (1999). A Pulitzer-Prize finalist and winner of the Aventis Prize for Science Books, "The Elegant Universe" became a PBS television special that Dr. Greene narrated. Another book, "The Fabric of the Cosmos" (2004), also was a New York Times bestseller.

Attesting to Dr. Greene’s popularity with the general public, his St. John’s lecture attracted people of all ages - even children. During a lively question-and-answer session after the lecture, one boy eagerly waved his hand until Dr. Greene pointed to him. "How did the Big Bang get there out of nothing?" the boy asked.

Without missing a beat, Dr. Greene smiled and said, "I don’t know - nobody does. At Columbia, I direct the Institute for String, Cosmology and Astroparticle Physics. We’re trying to put String Theory and cosmology together to hopefully answer your question, to figure out what the nothingness is and how the 'somethingness' we know today emerged from it."

Though the concept of "super strings" is far from a "proven theory," said Dr. Greene said, many physicists believe it can lead to the unified theory that Einstein so passionately sought. 

A "Theory of Everything"
To explain, Dr. Green showed a film clip with an animated representation of the Big Bang - the mammoth explosion physicists say created the known universe.

"The universe came into existence as a very small, very dense entity," he said. "Then it went through an explosion, in which matter, space and time were thrown outward. As everything got bigger, it cooled. Structures congealed out of the primordial plasma... the stars and galaxies we see today."

"Here’s the thing," he said. "We can make use of the known laws of physics to turn this film back to a fraction of a second after the beginning. But if we try to go any further back, the laws of physics break down, giving us noise, static - a complete lack of understanding at what happened at time zero itself."

The reason is reality’s increasingly bizarre behavior as objects become smaller. Ordinary physical laws no longer apply to objects as small as scientists believe the universe was before the Big Bang. To understand what happened, scientists need a "theory of everything" to unify two seemingly conflicting theories of reality.

The first, said Dr. Greene, is Einstein’s "Special Theory of Relativity," a mathematically precise explanation for "the beautiful, geometric way" that gravity affects how objects move in the observable universe. The second is quantum mechanics, which physicists developed in the 1920s and 1930s to explain the very different behavior of atoms, molecules and sub-atomic particles.

"The older theories - including Einstein’s - gave wrong predictions for what was being observed on the smallest scales," said Dr. Greene. "This alerted a generation of scientists that they needed to develop laws for the micro-world. Quantum mechanics is what they came up with."

This new theory depicts a "micro reality" seemingly at odds with the more orderly reality described by Einstein and earlier theorists. For example, conventional theories maintain that objects like electrons can never penetrate an apparently solid barrier. "Quantum mechanics says it can," said Dr. Greene. "The experiments found that every so often, electrons shot at a barrier will penetrate it."

The Big, the Small and Uncertainty
Unlike the seemingly predictable "big" universe, the "micro-world" follows principles strangely at odds with observed reality. In experiments with particles, said Dr. Greene, scientists who plot an electron’s location suddenly are unable to calculate its speed. Likewise, calculating an electron’s speed seems to interfere with calculating its location.

Dr. Greene referred to a mealtime dilemma familiar to many New Yorkers. "Since we’re in the vicinity of Chinatown," he said, "let’s use the analogy of a special order menu. You have Column ‘A’ and Column ‘B.’ If you order a dish from Column ‘A,’ the manager will say you can’t order a corresponding dish from the other column."

"That," he continued, "is the principle in microscopic realm. The more you know about an element from the first list, the more that knowledge fundamentally compromises your ability to understand features from the corresponding list."

In other words, he said, "the more you know about an electron’s position, the less you can know about its speed; the more you know about its speed, the less you can know of its position."

"Due to quantum uncertainty, there is a fundamental limit to what we can know." Though this is especially true on the micro-level, Dr. Greene added, uncertainty does exist in the observable universe, but its effects decrease as we enlarge our scale.

Resolving the Conflict
To understand the Big Bang, and what came before it, scientists must reconcile the different physical laws governing the big and small. "Superstring Theory" appears to do just that.

"I think we are not merely trying to model the universe," said Dr. Greene. "We are trying to figure out the truth about how it works. If there’s a clash in theories about the universe -- a point where known laws break down -- then there must be a deeper story to tell."

Identifying "the finest entities making up matter," said Dr. Greene, is the place to start. Conventional theories hold that the smallest particles of matter are quarks - "tiny dots with nothing inside."

"String theory challenges that," he said. "Inside those quarks, those tiny dots, is something finer: a tiny filament of string-like energy that vibrates in different patterns, like strings on a cello." The ways the filaments vibrate create the next smallest level of particles, like quarks, electrons and protons.

Moreover, said Dr. Green, the shape of the tiniest particles can build bridge the gulf between relativity and quantum mechanics. "How does it unify the laws of big and small?" said Dr. Greene. "When you have a string rather than a dot as the smallest particle, you spread it out. When you spread something out, you dilute it, the way ink dilutes as it spreads out in water."

This "spreading out" can explain why physical laws at the smallest levels of reality are so volatile - "jittery," in Dr. Greene’s words - while the larger-scale, observable universe seems more orderly. "Spreading out particles dilutes the ‘jitters’ in space," he said. "It becomes less severe." The more volatile physical reality of the smallest reality can reach "the right intensity" to fit the larger scale universe.

According to Dr. Greene, the theory also can explain a more esoteric aspect of reality. To hold together, the mathematics of string theory requires ten dimensions rather than three. The existence of ten dimensions - "curled up" realities presumably two small for human beings to observe - might explain another discovery that physicists have made.

"Over the last 100 years," said Dr. Greene, "physicists and other scientists have measured the features" that seem to make up reality. As a result, they have identified "twenty key numbers, encapsulating such features as the mass of electrons, the strength of gravity."

"No one knows why the numbers have the precise values they do," he continued. "But if we were to change any of those numbers by even a small percent, the universe as we know it would go away. Fiddle with the value of those numbers, and nuclear processes could not happen, and stars would not light up."

The concept of ten dimensions, said Dr. Greene, could explain why those critical numbers possess the values they do. The shape of the dimensions - "complex manifolds, with a rich geometry" - could influence the vibrations of strings "just as the shape of a French horn influences the sound patterns" produced by breath moving through the instrument’s valves.

Just the Beginning
After the lecture, Dr. Greene made time to autograph copies of his books and to pose for photographs with admirers. Before breaking for a special reception, however, he answered a barrage of audience questions - including one from Dr. Jeffrey Fagen, Dean of St. John’s College of Liberal Arts and Sciences.

"If ‘String Theory’ does prove to be true," asked Dean Fagen, "will I still need a physics department?"
Laughing, Dr. Greene assured the audience that finding a "Theory of Everything" would not end the quest for learning more about the universe.

"To my mind," he said, "this is a beginning, not an end. We’re trying to figure out the rules of the universe... when we have those rules, that’s where the fun begins. So yes, I still think you’ll need a physics department."

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This lecture by one of the world’s leading physicists offers a striking example of the intellectual discourse available to students, faculty and alumni of St. John’s University. We invite you to relive the excitement of the event by viewing our Photo Gallery.