A high school junior, I walked into a Syracuse movie theater in May 1977. When I walked out, nothing was the same. That opening shot, in which a star destroyer flew endlessly out of the screen, sent my heart racing. I had never before visited such a bizarre, exhilarating, awe-inspiring, fully realized universe. I wanted to live in that "galaxy far, far away." And so I did, for two hours at a time. Many, many times.

I was already fascinated by the idea of space travel, and Star Wars fueled my interest in space exploration and the possibility of alien life. As I went through college studying astrophysics, though, I was taught again and again the scientific truths that made Star Wars impossible. We cannot travel faster than the speed of light. Life on Earth arose through such an unlikely combination of factors that the chance that all these factors would exist on another planet to create alien life is vanishingly small. Sophisticated robots, when we can build them, will not act human and emotional, but will be logical. And the Force? Pure fantasy.

There was an occasional dissenting voice, but for the most part scientists found the universe of George Lucas incompatible with what they knew.

To be fair, I don't think George Lucas was particularly concerned with science when he created Star Wars. Those opening words quoted above sound more like the beginning of a fairy tale than a science fiction saga. And in many ways Star Wars feels like fantasy, with the mystical power of the Force; great wizards, called Jedi Knights, who wield it; and great powers of good and evil locked in an epic battle. In creating the part science fiction/part fantasy/part myth that is Star Wars, George Lucas did not seek to create a futuristic universe that agreed perfectly with our current understanding of science. If he had, it would have made for some very slow-moving movies. Instead, he sought to combine elements from many different sources and alchemize them into something completely new. And he succeeded.

Yet Star Wars contains spaceships, aliens, bizarre planets, and high-tech weapons-- all the ingredients of science fiction. These "scientific" elements make the fantastic seem more plausible. Yet how realistic, how possible, is this "galaxy far, far away"?

The answer when A New Hope first came out was "not at all." But a strange thing has happened in the years since Star Wars first came out. Science is beginning to catch up with George Lucas.

Physicists have come up with theoretical methods of rapid interstellar space travel. Recent discoveries suggest alien planets and alien life are much more common than we previously believed. Many robotocists now think emotions may be a key component in creating intelligent robots. And the Force? A few scientists have theories that can incorporate it.

We have discovered that the universe is a far, far stranger place than we had thought, full of surprises and ever-new mysteries. Say something is impossible today, and you will be explaining how it can be done tomorrow. So while George Lucas may not have attempted to create a scientifically accurate universe, science may actually be turning his vision into truth.

That's not to say Star Wars doesn't occasionally screw up big time in its science. Han Solo's boast that he made the Kessel Run in less than twelve parsecs is perhaps the most notorious scientific error in the Star Wars films. Since the parsec is a unit of distance, Han is bragging, in essence, that he got to Kessel in twelve miles. Not terribly impressive, if it's twelve miles from here to Kessel.

But the purpose of this book is not to nitpick. The purpose is to scientifically explore the Star Wars universe we love so deeply. What can the latest research and theories tell us about making the jump to hyperspace, dueling with light sabers, meeting an alien like Jar Jar Binks, sending an Artoo unit on a secret mission, or levitating an object with the Force? The incredible discoveries science is making can bring us some fascinating insights. And examining the possibilities raised in the movies leads us to some of the most compelling frontiers of science, areas where our very conception of reality breaks down, where mysteries remain unanswered, and where we come up against the ultimate questions of existence.

This book is written so that no particular science background is necessary to understand it. Each topic builds on what has come before, so you'll probably get the most enjoyment out of the book if you read it in order. If you need a reminder about what a particular term means, look in the index to find the page on which the term is first mentioned. That page should provide an explanation. All the measurements in the book are given in the U.S. customary system, with length in feet or miles and temperature in degrees Fahrenheit, unless otherwise stated.

The book covers the four Star Wars films: A New Hope (originally titled Star Wars), The Empire Strikes Back, The Return of the Jedi, and The Phantom Menace. You should be aware, though, that I am writing this book before The Phantom Menace is released. I have gathered information about the movie from a variety of sources, but I haven't yet seen it. I also occasionally include issues from the Star Wars books or comics, when they seem to shed light on an issue. If you haven't seen the movies recently, you may want to watch them again as you read the book (as if you need a reason to watch them again!).

The book also contains the opinions, expertise, and reactions of some of the top scientists in the fields discussed. What I found in talking with many of them was not only a true love for Star Wars, but the belief that a future involving many of the elements we see in the movies may well someday be possible.

When George Lucas first brought Star Wars to the screen in 1977, he was a dreamer. After watching Star Wars, I-- like many fans-- wanted to live that dream, to live in "a galaxy far, far away." The discoveries of science may actually one day allow that dream to become a reality.