One of the most exciting scientific adventures of all time is the search for the ultimate nature of physical reality, a hunt that in the past century has yielded such breakthroughs as Einstein's theory of relativity and quantum mechanics, two theories that radically altered our picture of space, time, gravity, and the fundamental building blocks of matter.
The latest advance in this epic quest is string theory—known as superstring or M-theory in its most recent versions. The "M" of M-theory is an arbitrary label, but some physicists believe it stands for mysterious or magical. Marvelous also qualifies, because there is something quite wonderful about this beautiful and startling idea.
Based on the concept that all matter is composed of inconceivably tiny filaments of vibrating energy, string theory has potentially staggering implications for our understanding of the universe.
Wouldn't you love to understand string theory at a deeper level than is available from popular articles or even book-length treatments? Aren't you eager to look over the shoulder of a prominent string theorist at work—one who has a gift for explaining the subject to nonscientists and who has created computer-generated images to help make the concepts clear?
A Challenging Course in a Fascinating Field
The Teaching Company offers just such a guide in Professor S. James Gates Jr., director of the Center for String and Particle Theory at the University of Maryland. Professor Gates is an old hand in this very young field. In 1977 he wrote the Massachusetts Institute of Technology's first-ever doctoral dissertation on supersymmetry, the precursor to string theory.
In the midst of teaching, pursuing research, and writing scores of scientific papers over the past two decades, Dr. Gates has also presented nearly 100 public talks on string theory, honing a set of visual aids designed to convey the difficult mathematical ideas that underlie this subject to a lay audience.
The 24 lectures in Superstring Theory: The DNA of Reality incorporate Dr. Gates's field testing of this matchless set of graphics, which are the most technically lavish that The Teaching Company has ever presented. Prepare to be intrigued, enlightened, and amazed.
Because the goal of string theory is to unite relativity and quantum mechanics in a comprehensive "theory of everything," this course nicely complements two other Teaching Company courses: Professor Richard Wolfson's Einstein's Relativity and the Quantum Revolution: Modern Physics for Non-Scientists, 2nd Edition, and Professor Steven Pollack's Particle Physics for Non-Physicists: A Tour of the Microcosmos.
Combined with Superstring Theory: The DNA of Reality, this trio of Teaching Company courses traces the development of physics in the 20th century—from well-tested theories such as relativity and quantum mechanics, to the more abstract research of late 20th-century particle physics, to the strange world of string theory, which is still in an intense state of flux.
The essence of string theory is that the smallest, most fundamental objects in the universe are not little balls knocking around like billiards, as had been thought for about 2,000 years. Instead, these small objects are supermicroscopic filaments—like tiny strands of spaghetti—whose different vibrational modes produce the multitude of particles that are observed in the laboratory.
So when a string vibrates in one way, it might appear to be an electron. If it vibrates in a different manner, it would look like a quark. It could vibrate in a third way and display the properties of a photon. Or perhaps it vibrates in a fourth mode and physicists say, "That's a graviton!" This gives strings an inherent ability to unify phenomena that had always been assumed to be different. If string theory ultimately proves correct, then strings are truly the DNA of reality.
One of the most celebrated features of the string approach is that it predicts more dimensions than the three of our familiar spatial world plus one of time. Currently, the most comprehensive version of string theory—M-theory—calls for a total of 11 dimensions. These extra dimensions could be hidden away, compacted into exotic shapes like the "Calabi-Yau manifold," or they could be forever out of reach in high-dimensional membranelike objects called branes.
But some physicists—Dr. Gates among them—see strings as entirely consistent with the four-dimensional world as we experience it. He explains this intriguing interpretation in Lecture 16.
Explore Ideas through Images
Each lecture draws on the illustrative power of computer-generated imagery (CGI). For years Dr. Gates has been asked to write a nontechnical book on string theory, but he has always declined, convinced that words alone cannot convey to the public the mathematical ideas that provide the foundation of this field. But these video lectures can. "The format of courses followed by The Teaching Company provides an exquisite platform for the utilization of CGI technology to augment conventional static lectures and books," he says.
Here are some of the mathematical ideas that you will explore through images in this course:
- Dark matter: Two animations of galaxies in the process of forming show that something is wrong with the scene that is based on the observable mass of an average galaxy: There is not enough matter for it to hold its shape. On the other hand, the galaxy with added "dark" matter does just fine. String theory accounts for the existence of this dark matter.
- What would happen if the sun disappeared? If the sun suddenly vanished, Earth would have 8 minutes before going dark, since it takes that long for the sun's light to reach us. But what about the sun's gravity? Would there be a similar delay, or would Earth go flying out of its orbit immediately? The answer to this question inspired one of the major theoretical goals of string theory.
- Designer atoms: The configuration of subatomic particles in an atom is specified by a set of equations. These can be visualized, showing that if you alter the equations to change one type of particle into another, the atom collapses, rendering all life impossible.
- Sizzling black holes: Physicist Stephen Hawking proposed that black holes do more than just bend light around them; they also give off a "sizzle" of static. Even though a black hole is itself invisible, these effects can be detected and visualized with computer graphics. Hawking's brilliant insight eventually led others to develop the first string theory.
- Einstein's hypotenuse: Many of the ideas developed by Einstein, including E = mc², can be understood by analyzing a geometric figure called Einstein's hypotenuse. Use of this concept in early versions of string theory led to a bizarre particle called the tachyon.
This course is an immensely rich experience, filled with unexpected delights and mysterious encounters. You will often feel like a tourist in an exotic country, where the sights, sounds, aromas, and incidents are at times baffling but always invigorating and educational, leaving you with a desire to understand this complex world better.
If you've ever wanted to know what string theory is all about; or what theoretical physicists discuss over dinner; or how mathematical ideas guide our exploration of inconceivably tiny realms; or if you've ever wanted a glimpse of cutting-edge ideas about the fundamental structure of reality—then, by all means, we invite you to let Professor Gates be your guide into the amazing world of strings.