For the Love of Physics (5 page)

I was afraid a lot. And I know it sounds ridiculous, but I was the only male, so I sort of became the man of the house, even at age seven and eight. In The Hague, where we lived, there were many broken-down houses on the coast, half-destroyed by the Germans who were building bunkers on our beaches. I would go there and steal wood—I was going to say “collect,” but it was stealing—from those houses so that we had some fuel for cooking and for heat.

To try to stay warm in the winters we wore this rough, scratchy, poor-quality wool. And I still cannot stand wool to this day. My skin is so sensitive that I sleep on eight-hundred-thread-count cotton sheets. That’s also why I order very fine cotton shirts—ones that do not irritate my skin. My daughter Pauline tells me that if I see her wearing wool, I still turn away; such is the effect the war still has on me.

My father returned while the war was still going on, in the fall of 1944. People in my family disagree about just how this happened, but as near as I can tell it seems that my wonderful aunt Lauk, my mother’s sister, was in Amsterdam one day, about 30 miles away from The Hague, and she caught sight of my father! She followed him from a distance and saw him go into a house. Later she went back and discovered that he was living with a woman.

My aunt told my mother, who at first got even more depressed and upset, but I’m told that she collected herself and took the boat to Amsterdam (trains were no longer operating), marched right up to the house, and rang the bell. Out came the woman, and my mother said, “I want to speak to my husband.” The woman replied, “
I
am the wife of Mr. Lewin.” But my mother insisted: “I want my husband.” My father came to the door, and she said, “I’ll give you five minutes to pack up and come back with me or else you can get a divorce and you’ll never see your children again.” In three minutes he came back downstairs with his things and returned with her.

In some ways it was much worse when he was back, because people knew that my father, whose name was also Walter Lewin, was a Jew. The Resistance had given him false identification papers, under the name of Jaap Horstman, and my sister and I were instructed to call him Uncle Jaap. It’s a total miracle, and doesn’t make any sense to Bea and me to this very day, but no one turned him in. A carpenter made a hatch in the ground floor of our house. We could lift it up and my father could go down and hide in the crawl space. Remarkably, my father managed to avoid capture.

He was probably at home eight months or so before the war ended,
including the worst time of the war for us, the winter of 1944 famine, the
hongerwinter
. People starved to death—nearly twenty thousand died. For heat we crawled under the house and pulled out every other floor joist—the large beams that supported the ground floor—for firewood. In the hunger winter we ate tulip bulbs, and even bark. People could have turned my father in for food. The Germans would also pay money (I believe it was fifty guilders, which was about fifteen dollars at the time) for every Jew they turned in.

The Germans did come to our house one day. It turned out that they were collecting typewriters, and they looked at ours, the ones we used to teach typing, but they thought they were too old. The Germans in their own way were pretty stupid; if you’re being told to collect typewriters, you don’t collect Jews. It sounds like a movie, I know. But it really happened.

After all of the trauma of the war, I suppose the amazing thing is that I had a more or less normal childhood. My parents kept running their school—the Haagsch Studiehuis—which they’d done before and during the war, teaching typing, shorthand, languages, and business skills. I too was a teacher there while I was in college.

My parents patronized the arts, and I began to learn about art. I had an academically and socially wonderful time in college. I got married in 1959, started graduate school in January 1960, and my first daughter, Pauline, was born later that year. My son Emanuel (who is now called Chuck) was born two years after that, and our second daughter, Emma, came in 1965. Our second son, Jakob, was born in the United States in 1967.

When I arrived at MIT, luck was on my side; I found myself right in the middle of the explosion of discoveries going on at that time. The expertise I had to offer was perfect for Bruno Rossi’s pioneering X-ray astronomy team, even though I didn’t know anything about space research.

V-2 rockets had broken the bounds of the Earth’s atmosphere, and a whole new vista of opportunity for discoveries had been opened up.
Ironically, the V-2 had been designed by Wernher von Braun, who was a Nazi. He developed the rockets during World War II to kill Allied civilians, and they were terribly destructive. In Peenemünde and in the notorious underground Mittelwerk plant in Germany, slave laborers from concentration camps built them, and some twenty thousand died in the process. The rockets themselves killed more than seven thousand civilians, mostly in London. There was a launch site about a mile from my mother’s parents’ house close to The Hague. I recall a sizzling noise as the rockets were being fueled and the roaring noise at launch. In one bombing raid the Allies tried to destroy V-2 equipment, but they missed and killed five hundred Dutch civilians instead. After the war the Americans brought von Braun to the United States and he became a hero. That has always baffled me. He was a war criminal!

For fifteen years von Braun worked with the U.S. Army to build the V-2’s descendants, the Redstone and Jupiter missiles, which carried nuclear warheads. In 1960 he joined NASA and directed the Marshall Space Flight Center in Alabama, where he developed the Saturn rockets that sent astronauts to the Moon. Descendants of his rockets launched the field of X-ray astronomy, so while rockets began as weapons, at least they also got used for a great deal of science. In the late 1950s and early 1960s they opened new windows on the world—no, on the universe!—giving us the chance to peek outside of the Earth’s atmosphere and look around for things we couldn’t see otherwise.

To discover X-rays from outer space, Rossi had played a hunch. In 1959 he went to an ex-student of his named Martin Annis, who then headed a research firm in Cambridge called American Science and Engineering, and said, “Let’s just see if there are X-rays out there.” The ASE team, headed by future Nobelist Riccardo Giacconi, put three Geiger-Müller counters in a rocket that they launched on June 18, 1962. It spent just six minutes above 80 kilometers (about 50 miles), to get beyond the Earth’s atmosphere—a necessity, since the atmosphere absorbs X-rays.

Sure enough, they detected X-rays, and even more important, they were able to establish that the X-rays came from a source outside the
solar system. It was a bombshell that changed all of astronomy. No one expected it, and no one could think of plausible reasons why they were there; no one really understood the finding. Rossi had been throwing an idea at the wall to see if it would stick. These are the kinds of hunches that make a great scientist.

I remember the exact date I arrived at MIT, January 11, 1966, because one of our kids got the mumps and we had to delay going to Boston; the KLM wouldn’t let us fly, as the mumps is contagious. On my first day I met Bruno Rossi and also George Clark, who in 1964 had been the first to fly a balloon at a very high altitude—about 140,000 feet—to search for X-ray sources that emitted very high energy X-rays, the kind that could penetrate down to that altitude. George said, “If you want to join my group that would be great.” I was at exactly the right place at the right time.

If you’re the first to do something, you’re bound to be successful, and our team made one discovery after another. George was very generous; after two years he turned the group completely over to me. To be on the cutting edge of the newest wave in astrophysics was just remarkable.

I was incredibly fortunate to find myself right in the thick of the most exciting work going on in astrophysics at that time, but the truth is that all areas of physics are amazing; all are filled with intriguing delights and are revealing astonishing new discoveries all the time. While we were finding new X-ray sources, particle physicists were finding ever more fundamental building blocks of the nucleus, solving the mystery of what holds nuclei together, discovering the W and Z bosons, which carry the “weak” nuclear interactions, and quarks and gluons, which carry the “strong” interactions.

Physics has allowed us to see far back in time, to the very edges of the universe, and to make the astonishing image known as the Hubble Ultra Deep Field, revealing what seems an infinity of galaxies. You should not finish this chapter without looking up the Ultra Deep Field online. I have friends who’ve made this image their screen saver!

The universe is about 13.7 billion years old. However, due to the fact
that space itself has expanded enormously since the big bang, we are currently observing galaxies that were formed some 400 to 800 million years after the big bang and that are now considerably farther away than 13.7 billion light-years. Astronomers now estimate that the edge of the observable universe is about 47 billion light-years away from us in every direction. Because of the expansion of space, many faraway galaxies are currently moving away from us faster than the speed of light. This may sound shocking, even impossible, to those of you raised on the notion that, as Einstein postulated in his theory of special relativity, nothing can go faster than the speed of light. However, according to Einstein’s theory of general relativity, there are no limits on the speed between two galaxies when space itself is expanding. There are good reasons why scientists now think that we are living in the golden age of cosmology—the study of the origin and evolution of the entire universe.

Physics has explained the beauty and fragility of rainbows, the existence of black holes, why the planets move the way they do, what goes on when a star explodes, why a spinning ice skater speeds up when she draws in her arms, why astronauts are weightless in space, how elements were formed in the universe, when our universe began, how a flute makes music, how we generate electricity that drives our bodies as well as our economy, and what the big bang sounded like. It has charted the smallest reaches of subatomic space and the farthest reaches of the universe.

My friend and colleague Victor Weisskopf, who was already an elder statesman when I arrived at MIT, wrote a book called
The Privilege of Being a Physicist.
That wonderful title captures the feelings I’ve had being smack in the middle of one of the most exciting periods of astronomical and astrophysical discovery since men and women started looking carefully at the night sky. The people I’ve worked alongside at MIT, sometimes right across the hall from me, have devised astonishingly creative and sophisticated techniques to hammer away at the most fundamental questions in all of science. And it’s been my own privilege both to help extend humankind’s collective knowledge of the stars and the universe
and to bring several generations of young people to an appreciation and love for this magnificent field.

Ever since those early days of holding decaying isotopes in the palm of my hand, I have never ceased to be delighted by the discoveries of physics, both old and new; by its rich history and ever-moving frontiers; and by the way it has opened my eyes to unexpected wonders of the world all around me. For me physics is a way of seeing—the spectacular and the mundane, the immense and the minute—as a beautiful, thrillingly interwoven whole.

That is the way I’ve always tried to make physics come alive for my students. I believe it’s much more important for them to remember the beauty of the discoveries than to focus on the complicated math—after all, most of them aren’t going to become physicists. I have done my utmost to help them see the world in a different way; to ask questions they’ve never thought to ask before; to allow them to see rainbows in a way they have never seen before; and to focus on the exquisite beauty of physics, rather than on the minutiae of the mathematics. That is also the intention of this book, to help open your eyes to the remarkable ways in which physics illuminates the workings of our world and its astonishing elegance and beauty.

CHAPTER 2

Measurements, Uncertainties, and the Stars

My Grandmother and Galileo Galilei

Physics is fundamentally an experimental science, and measurements and their uncertainties are at the heart of every experiment, every discovery. Even the great theoretical breakthroughs in physics come in the form of predictions about quantities that can be measured. Take, for example, Newton’s second law,
F
=
ma
(force equals mass times acceleration), perhaps the most important single equation in physics, or Einstein’s
E
=
mc
²
(energy equals mass times the square of the speed of light), the most renowned equation in physics. How else do physicists express relationships except through mathematical equations about measurable quantities such as density, weight, length, charge, gravitational attraction, temperature, or velocity?