Fear of Physics

Table of Contents

 

 

 

 

 

I was quite excited when my editors at Basic contacted me, asking if I would be interested in revising and updating
Fear of Physics
. In the fifteen years since this book first appeared, a tremendous amount has changed in our understanding of forefront concepts in the world of physics, and even some of our guiding principles have altered. In addition, my own perspective on what issues are important, especially vis-à-vis public interest in science, has also evolved, both due to my own evolution as a scientist, but also to my subsequent experiences as a writer.

At the same time, I was surprised about ten years ago when I was delivering a series of lectures to high school physics teachers to discover that this book had become something of a “cult classic,” often handed out to promising high school students to help turn them on to modern topics in physics. One physics club sent me a copy of a T-shirt they had designed with a cow as a sphere in honor of the book. Thus, in spite of the fact that I originally intended this book for an audience with little or no background in
science, indeed to include many who might otherwise feel intimidated by physics, I realized that something about the connection between forefront physics and fundamental ideas excited budding young scientists too, as well it should.

With these thoughts in mind, I have revised the book from beginning to end, keeping within the original framework, but updating it with new material to make it more accessible to some, more exciting for others, and to capture the evolving nature of science right up to the present moment as we explore the distant reaches of the universe. I hope that you enjoy this new version as much as I have enjoyed revisiting it.

 

Lawrence M. Krauss
Cleveland, Ohio
November 2006

When someone at a party learns that I am a physicist, he or she immediately either (1) changes the subject, or (2) asks about the big bang, other universes, warp drive, quarks, or one of the trilogy of recent “super” developments: superconductors, superstrings, or supercolliders. Even people who freely admit having avoided physics in high school and never looked back are still sometimes fascinated with the esoteric phenomena at the forefront of the field, although they often don’t realize it is physics they are interested in. Physics deals with many of the cosmic questions that, in one way or another, everyone has mused about. However, physics often appears foreign and inaccessible, due in part to the fact that research at the forefront is at times far removed from everyday experience.

But there is a more basic obstacle that gets in the way of appreciating where modern physics is going. The way physicists approach problems, and the language they use, is also removed from the mainstream of modern-day activity for most people. Without a common gestalt to guide the observer, the menagerie
of phenomena and concepts attached to modern physics remains disconnected and intimidating.

To present modern physics as I understand it, I thought I would concentrate not on particular theories but rather on the tools that guide physicists in their work. If one wants to gain an appreciation for the current directions of modern physics, both as a human intellectual activity and as the basis for our modern picture of the universe, it is much easier to do so if you first have some notion of how the enterprise is carried out. What I want to present here, then, is not so much a trail guide through the modern physics jungle as a guide on how to hike in the first place: what equipment to bring, how to avoid cliffs and dead ends, what kind of trails are likely to be the most exciting, and how to get home safely.

Physicists themselves can follow modern developments only because they are largely based on the same handful of fundamental ideas that have been successfully applied to study the everyday world. Physical theory at present deals with phenomena occurring on scales of space and time varying by over sixty orders of magnitude—meaning that the ratio of the largest to the smallest is 1 followed by 60 zeros. Experiments cover a somewhat smaller range, but not much smaller. Yet amid this menagerie, any phenomenon described by one physicist is generally accessible to any other through the use of perhaps a dozen basic concepts. No other realm of human knowledge is either so extensive or so simply framed.

Partly for this reason, this book is short. The tools that guide physics are few in number, and while it may take an advanced degree to master them, it doesn’t require a massive tome to elucidate them. So as you wander through each of the six chapters (once you BUY it, of course!), you will find a discussion of a key
idea or theme that guides physicists in their search. To illustrate these ideas, I have chosen examples that run the gamut in physics, from the basics to the stuff the New York Times science writers will cover this week. The choice may seem at times eclectic. But, while concentrating at the beginning on what has guided physicists to get where we are, I will be concentrating by the end on what is leading us to go where we are going.

Also, for this reason, I have taken the liberty to introduce concepts that are quite modern to illustrate a theme. Some readers may find these a pleasant relief from ideas they are already familiar with. Others may find them momentarily elusive. Some of these ideas, while fundamental, have never before been presented in the popular literature. No matter. You won’t be tested. My intent is more to present the flavor of physics than it is to master its substance. I think it is insight, rather than a working knowledge, that is most useful and is needed by nonscientists in today’s world, and so it is insight that I am aiming at.

Most important, there are subtle and wonderful connections between many of the short vignettes I shall present that run below the surface. It is these connections that form the fabric of physics. It is the joy of the theoretical physicist to discover them, and of the experimentalist to test their strength. In the end, they make physics accessible. If you get interested enough to crave more comprehensive discussions, there are lots of further resources.

Finally, I want to stress that physics is a human creative intellectual activity, like art and music. Physics has helped forge our cultural experience. I am not sure what will be most influential in the legacy we pass on, but I am sure that it is a grave mistake to ignore the cultural aspect of our scientific tradition. In the end, what science does is change the way we think about the world
and our place within it. To be scientifically illiterate is to remain essentially uncultured. And the chief virtue of cultural activity—be it art, music, literature, or science—is the way it enriches our lives. Through it we can experience joy, excitement, beauty, mystery, adventure. The only thing that I think really differentiates science from the other things on this list is that the threshold is a little bit higher before the feedback starts. Indeed, the major justification for much of what we physicists do is the personal pleasure we get from doing physics. There is universal joy in making new connections. There is excitement and beauty in both the diversity of the physical world and the simplicity of its fundamental workings. So, with apologies to Erica Jong, this book is dedicated to the question: Is it possible for the average person to shed inhibitions, let go, and just enjoy the basic, simple pleasure of physics? I hope so.

This book would not have appeared at all, or at least would not have appeared in its present form, were it not for a number of people. First, Martin Kessler, president of Basic Books, conned me over breakfast almost twenty years ago into turning my ideas about how physicists think about physics into what sounded like an ambitious book. Within a year we had signed a contract, which he kindly put on hold so that I could write another book for Basic on a subject that I then thought was more timely. My editor for that project, Richard Liebmann-Smith, became a good friend, and before he left Basic Books our conversations about this book helped refine my vision about what I wanted to accomplish.

Fear of Physics became something quite different from what I had originally envisaged. It became something I hoped my wife, Kate, would want to read. And, in fact, she provided constant input as I tested out my ideas and presentations on her. Indeed, the first chapter was not sent out to the publisher until it had earned her seal of approval for readability and interest. Finally, Susan Rabiner, senior science editor at Basic Books, played a vital role in bringing the first edition to completion. It was she who
convinced me that my new vision was workable and, more important, that Basic Books was prepared to produce and sell a book of this type. Once we had this settled and I had finally produced a chapter that conveyed what I wanted in the style I wanted, Susan was indefatigable. Her enthusiastic support for this book provided constant motivation. In particular, her scheduling of such things as the cover and the copyediting well in advance made my commitment seem ever more real and helped me complete the manuscript more or less on time—something new for me.

During the course of the writing, I have had the opportunity to discuss various ideas contained here with different people. As I have said, my wife often provided a filter through which things did not pass. I wish also to thank the numerous students I have taught over the years in physics courses for “nonscientists” who have helped me refine my thoughts by making it clear when something did not work. I fear I may have gained more from this process than they did. I also had the opportunity, through my work long ago at the Ontario Science Centre, to help build an appreciation of what nonphysicists might find comprehensible and what they might want to comprehend—often two different things. Finally, my teachers, and later my colleagues and collaborators, have influenced this work both directly and indirectly. There are too many individuals in this group to list by name. They know who they are, and I thank them. Next, as anyone who reads this book will quickly realize, Richard Feynman played an influential role in my thinking about a number of areas of physics, as I am sure he did for many physicists. I also want to thank Subir Sachdev for useful discussions that helped me refine my discussion of phase transitions in matter, Martin White and Jules Coleman for reading the manuscript and providing comments, and Jatila Van der Veen-Davis and Jennifer Elizabeth Marsh in her introductory
physics class at UCSB for using the draft version and finding an error.

Last but not least, I want to thank my daughter, Lilli, for lending me her computer during several periods when mine was broken. In a very real sense, this book would not have appeared now without her help. Both Lilli and Kate sacrificed precious time we could have spent together while I worked on this book, and I hope to make it up to them.

—Louise Bogan,
Journey Around My Room

PART ONE

ONE

A physicist, an engineer, and a psychologist are called in as consultants to a dairy farm whose production has been below par. Each is given time to inspect the details of the operation before making a report.

The first to be called is the engineer, who states: “The size of the stalls for the cattle should be decreased. Efficiency could be improved if the cows were more closely packed, with a net allotment of 275 cubic feet per cow. Also, the diameter of the milking tubes should be increased by 4 percent to allow for a greater average flow rate during the milking periods.”

The next to report is the psychologist, who proposes:

“The inside of the barn should be painted green. This is a more mellow color than brown and should help induce greater milk flow. Also, more trees should be planted in the fields to add diversity to the scenery for the cattle during grazing, to reduce boredom.”

Finally, the physicist is called upon. He asks for a blackboard and then draws a circle. He begins: “Assume the cow is a sphere. . . .”