For the Love of Physics (42 page)

The fact that most of us find their works beautiful now shows that the artists triumphed over their age: their new way of seeing, their new way of looking at the world, has become our world, our way of seeing. What was just plain ugly a hundred years ago can now be beautiful. I love the fact that a contemporary critic called Matisse the apostle of ugliness. The
collector Leo Stein referred to his painting of Madame Matisse,
Woman with a Hat
, as “the nastiest smear I have ever seen”—but he bought the painting!

In the twentieth century artists used found objects—sometimes shocking ones, like Marcel Duchamp’s urinal (which he called “fountain”) and his Mona Lisa, on which he wrote the provocative letters L.H.O.O.Q. Duchamp was the great liberator; after Duchamp anything goes! He wanted to shake up the way we look at art.

No one can look at color in the same way after van Gogh, Gauguin, Matisse, and Derain. Nor can anyone look at a Campbell’s soup can or an image of Marilyn Monroe in the same way after Andy Warhol.

Pioneering works of art can be beautiful, even stunning, but most often—certainly at first—they are baffling, and may even be ugly. The real beauty of a pioneering work of art, no matter how ugly, is in its meaning. A new way of looking at the world is never the familiar warm bed; it’s always a chilling cold shower. I find that shower invigorating, bracing, liberating.

I think about pioneering work in physics in this same way. Once physics has taken another of its wonderfully revelatory steps into previously invisible or murky terrain, we can never see the world quite the same way again.

The many stunning discoveries I’ve introduced through this book were deeply perplexing at the time they were made. If we have to learn the mathematics behind those discoveries, it can be truly daunting. But I hope that my introduction of some of the biggest breakthroughs has brought to life just how exciting and beautiful they are. Just as Cézanne, Monet, van Gogh, Picasso, Matisse, Mondrian, Malevich, Kandinsky, Brancusi, Duchamp, Pollock, and Warhol forged new trails that challenged the art world, Newton and all those who have followed him gave us new vision.

The pioneers in physics of the early twentieth century—among them Antoine Henri Becquerel, Marie Curie, Niels Bohr, Max Planck, Albert Einstein, Louis de Broglie, Erwin Schrödinger, Wolfgang Pauli, Werner
Heisenberg, Paul Dirac, Enrico Fermi—proposed ideas that completely undermined the way scientists had thought about reality for centuries, if not millennia. Before quantum mechanics we believed that a particle is a particle, obeying Newton’s laws, and that a wave is a wave obeying different physics. We now know that all particles can behave like waves and all waves can behave like particles. Thus the eighteenth-century issue, whether light is a particle or a wave (which seemed to be settled in 1801 by Thomas Young in favor of a wave—see
chapter 5
), is nowadays a non-issue as it is both.

Before quantum mechanics it was believed that physics was deterministic in the sense that if you do the same experiment a hundred times, you will get the exact same outcome a hundred times. We now know that that is not true. Quantum mechanics deals with probabilities—not certainties. This was so shocking that even Einstein never accepted it. “God does not throw dice” were his famous words. Well, Einstein was wrong!

Before quantum mechanics we believed that the position of a particle and its momentum (which is the product of its mass and its velocity) could, in principle, simultaneously be determined to any degree of accuracy. That’s what Newton’s laws taught us. We now know that that is not the case. Nonintuitive as this may be, the more accurately you can determine its position, the less accurately can you determine its momentum; this is known as Heisenberg’s uncertainty principle.

Einstein argued in his theory of special relativity that space and time constituted one four-dimensional reality, spacetime. He postulated that the speed of light was constant (300,000 kilometers per second). Even if a person were approaching you on a superfast train going at 50 percent of the speed of light (150,000 kilometers per second), shining a headlight in your face, you and he would come up with the same figure for the speed of light. This is very nonintuitive, as you would think that since the train is approaching you, you who are observing the light aimed at you would have to add 300,000 and 150,000, which would lead to 450,000 kilometers per second. But that is not the case—according to Einstein, 300,000 plus 150,000 is still 300,000! His theory of general relativity was perhaps
even more mind-boggling, offering a complete reinterpretation of the force holding the astronomical universe together, arguing that gravity functioned by distorting the fabric of spacetime itself, pushing bodies into orbit through geometry, even forcing light to bend through the same distorted spacetime. Einstein showed that Newtonian physics needed important revisions, and he opened the way to modern cosmology: the big bang, the expanding universe, and black holes.

When I began lecturing at MIT in the 1970s, it was part of my personality to put more emphasis on the beauty and the excitement rather than the details that would be lost on the students anyway. In every subject I taught I always tried where possible to relate the material to the students’ own world—and make them see things they’d never thought of but were within reach of touching. Whenever students ask a question, I always say, “that’s an excellent question.” The absolute last thing you want to do is make them feel they’re stupid and you’re smart.

There’s a moment in my course on electricity and magnetism that’s very precious to me. For most of the term we’ve been sneaking up, one by one, on Maxwell’s equations, the stunningly elegant descriptions of how electricity and magnetism are related—different aspects of the same phenomenon, electromagnetism. There’s an intrinsic beauty in the way these equations talk to one another that is unbelievable. You can’t separate them; together they’re one unified field theory.

So I project these four beautiful equations on different screens on all the walls of the lecture hall. “Look at them,” I say. “Inhale them. Let them penetrate your brains. Only once in your life will you see all four of Maxwell’s equations for the first time in a way that you can appreciate them, complete and beautiful and talking to each other. This will never happen again. You will never be the same. You have lost your virginity.” In honor of this momentous day in the lives of the students, as a way of celebrating the intellectual summit they’ve reached, I bring in six hundred daffodils, one for each student.

Students write me many years afterward, long after they’ve forgotten the details of Maxwell’s equations, that they remember the day of the
daffodils, the day I marked their new way of seeing with flowers. To me this is teaching at the highest level. It’s so much more important to me for students to remember the beauty of what they have seen than whether they can reproduce what you’ve written on the blackboard. What counts is not what you cover, but what you uncover!

My goal is to make them love physics and to make them look at the world in a different way, and that is for life! You broaden their horizon, which allows them to ask questions they have never asked before. The point is to unlock the world of physics in such a way that it connects to the genuine interest students have in the world. That’s why I always try to show my students the forests, rather than take them up and down every single tree. That is also what I have tried to do in this book for you. I hope you have enjoyed the journey.

ACKNOWLEDGMENTS

W
ithout the intelligence, foresight, business sense, and moral support of our exceptional literary agent, Wendy Strothman,
For the Love of Physics
would have remained little more than wishful thinking. She brought the two of us together, found the right home for this book at Free Press, read numerous draft chapters with an editorial eye honed by her years as a publisher, gave the book its title, and helped keep us focused on the end product. We are also the happy and fortunate recipients of her staunch friendship, which buoyed us throughout the project.

It would be hard to overstate the contributions of our editor, Emily Loose, at Free Press, whose vision for this book proved infectious and whose extraordinarily close attention to prose narrative provided an education for both of us. Despite the enormous pressure in the publishing industry to cut corners on behalf of the bottom line, Emily insisted on really editing this book, pushing us always to greater clarity, smoother transitions, and tighter focus. Her skill and intensity have made this a far better book. We are grateful as well to Amy Ryan for her deft copyediting of the manuscript.

Walter Lewin:

Every day I receive wonderful, often very moving email from dozens of people all over the world who watch my lectures on the web. These lectures were made possible due to the vision of Richard (Dick) Larson. In
1998 when he was the director of the Center for Advanced Educational Services and a professor in the Department of Electrical Engineering at MIT, he proposed that my rather unconventional lectures be videotaped and made accessible to students outside MIT. He received substantial funding for this from the Lord Foundation of Massachusetts and from Atlantic Philanthropies. Dick’s initiative was the precursor of e-learning! When MIT’s OpenCourseWare opened its doors in 2001, my lectures reached all corners of the world and are now viewed by more than a million people each year.

During the past two years, even during the seventy days that I was in the hospital (and almost died), this book was always on my mind. At home I talked about it incessantly with my wife, Susan Kaufman. It kept me awake many nights. Susan patiently endured all this and managed to keep my spirits up. She also trained her astute editorial eye on a number of chapters and improved them markedly.

I am very grateful to my cousin Emmie Arbel-Kallus and my sister, Bea Bloksma-Lewin, for sharing with me some of their very painful recollections of events during World War II. I realize how difficult this must have been for both of them, as it was for me. I thank Nancy Stieber, my close friend for thirty years, both for always correcting my English and for her invaluable comments and suggestions. I also want to thank my friend and colleague George Clark, without whom I would never have become a professor at MIT. George let me read the original American Science and Engineering proposal submitted to the Air Force Cambridge Research Laboratories that led to the birth of X-ray astronomy.

I am grateful to Scott Hughes, Enectali Figueroa-Feliciano, Nathan Smith, Alex Filippenko, Owen Gingerich, Andrew Hamilton, Mark Whittle, Bob Jaffe, Ed van den Heuvel, Paul Murdin, George Woodrow, Jeff McClintock, John Belcher, Max Tegmark, Richard Lieu, Fred Rasio, the late John Huchra, Jeff Hoffman, Watti Taylor, Vicky Kaspi, Fred Baganoff, Ron Remillard, Dan Kleppner, Bob Kirshner, Paul Gorenstein, Amir Rizk, Chris Davlantes, Christine Sherratt, Markos Hankin, Bil Sanford, and Andrew Neely for helping me, when help was needed.

Finally I can’t thank Warren Goldstein enough for his patience with me and for his flexibility; at times he must have felt overwhelmed (and perhaps frustrated) with too much physics in too little time.

Warren Goldstein:

I would like to thank the following people for their willingness to talk with me about Walter Lewin: Laura Bloksma, Bea Bloksma-Lewin, Pauline Broberg-Lewin, Susan Kaufman, Ellen Kramer, Wies de Heer, Emanuel (Chuck) Lewin, David Pooley, Nancy Stieber, Peter Struycken. Even if they are not quoted in
For the Love of Physics
, each one added substantially to my understanding of Walter Lewin. Edward Gray, Jacob Harney, Laurence Marschall, James McDonald, and Bob Celmer did their best to keep Walter and me from making mistakes in their fields of expertise; as much as we’d prefer to put the onus on them, we take full responsibility for any remaining errors. I also want to thank William J. Leo, a 2011 graduate of the University of Hartford, for his assistance at a critical moment. Three of the smartest writers I know—Marc Gunther, George Kannar, and Lennard Davis—all gave me invaluable advice early in the project. In different ways Dean Joseph Voelker and Assistant Provost Fred Sweitzer of the University of Hartford made it possible for me to find the time to finish this book. I am deeply grateful to my wife, Donna Schaper—minister and organizer extraordinaire, and author of thirty books at last count—for understanding and celebrating my immersion in a foreign world. Our grandson, Caleb Benjamin Luria, came into the world October 18, 2010; it has been a delight to watch him undertake his own series of remarkable experiments in the physics of everyday life. Finally, I want here to express my deep gratitude to Walter Lewin, who taught me more physics in the last few years than either of us would have thought possible and rekindled a passion in me that had lain dormant far too long.

APPENDIX 1