I n this book, I aim to give you a clear understanding of Einstein’s beautiful work. Everyone knows that Einstein invented the theory of relativity and that he came up with that famous E = mc 2 equation. And everyone thinks that you need to be almost an Einstein to understand either one.
I am here to tell you that the theory of relativity isn’t really that difficult to understand. (Actually, there are two theories of relativity, the special and the general, and neither one is beyond your grasp.) And as for the famous equation, it too can be understood without using math.
In this book, I use Einstein’s own simple examples to explain his discovery that time slows down and distances shorten when you move fast. (I mean really fast — not just a steady jog.) I also tell you why, even if no one can ever reach the speed of light, a future astronaut may be able to circumnavigate the entire galaxy in a human lifetime. (Her lifetime, that is; hundreds of millions of years will pass for the Earthlings who stay behind.) That’s a form of time travel to the future, without the possibility of returning to the present. I also discuss whether it’s possible to really travel to the past or future and get back to the present.
About This Book
This book is intended as a guide to all of Einstein’s work, not just relativity and E = mc2. Einstein did much more than invent his theory of relativity and discover his famous equation. He started quantum physics, invented the principle of the laser, came up with the first model of the universe, and showed us that space is curved. And these are just the big-ticket items. There’s hardly any field in physics that’s untouched by his discoveries.
My aim with this book is to present and explain all the scientific contributions that Einstein made in his life in plain and simple English. My aim is also to tell you why Einstein’s discoveries are so important and why he deserves to be as famous as he is.
Einstein’s life was fascinating, so as I discuss his work I also give you an overview of the main events during different periods of his life. I tell you about Einstein’s views on religion and philosophy, as well as his interactions with the women in his life.
What You’re Not to Read
You don’t need to read this book from cover to cover. I’ve tried to make the chapters self-contained, so you can read about a specific topic in Einstein’s work and be able to follow the discussion.
Don’t read anything you don’t want to read. If you’re reading the book because you’re curious about what Einstein did, read about what you’d like to know. If you’re reading it because you’re taking a physics class and need to complement your textbook, read the parts that match your text.
You may just want to know about special relativity or what the E = mc2 equation means. Or you may be interested in what Einstein did during his miracle year. By all means, read what piques your interest. I promise I won’t test you on what you are learning. And I hope you’ll enjoy reading whatever you decide to read.
Of course, if you do decide to read this book from cover to cover, nobody will stop you. And no one will complain about how much you know about Einstein’s work.
Foolish Assumptions
I’m assuming that you bought the book (or borrowed it or maybe got it as a gift) because you always wanted to know about Einstein’s theories but you don’t necessarily want to read about them in a more standard science book. I’m also assuming that, right now, you don’t care to read a physics-type book with math or complicated diagrams in it. I’m also assuming that you are someone who enjoys learning new things. If this is the case, I hope you enjoy this voyage through Einstein’s universe.
How This Book Is Organized
The book follows Einstein’s life, to a certain extent. It starts with his miracle year and his unbelievable outburst into the world of physics, almost out of nowhere. During that year, Einstein started two revolutions in physics, the theory of relativity and quantum physics. The book follows the development of these two theories in a chronological order, and it ends with the impact of these two theories on the world of science.
Part I: A Genius Awakens
This first part tells you who Einstein was and introduces Einstein’s genius by following his life from birth to the search for a job after college graduation. This period in Einstein’s life ends with his miracle year, which I present in Chapter 3.
Part II: On the Shoulders of Giants: What Einstein Learned in School
This part is an overview of physics from its early development, back when it wasn’t called physics. I introduce the ancient Greeks’ very modern ideas about the world, and I present the important developments through Einstein’s time. I make stops to visit Galileo Galilei and Johannes Kepler, as well as a longer stay to see what the great Isaac Newton did. I follow the development of ideas on heat and energy, which Einstein changed. After that, I pay a visit to James Clerk Maxwell, the other great influence on Einstein. (Einstein skipped classes to read Maxwell’s papers in the library, and he developed relativity from his studies of Maxwell’s theories.) The part ends with what was known about the behavior of light before Einstein entered the picture.
Part III: The Special Theory of Relativity
You get to the real thing in this part: Einstein’s special theory of relativity. First, I introduce you to the original idea of relativity, the relativity of Galileo. I then explain what Einstein’s relativity is all about and how Einstein, at 26, went about developing it in a few weeks. In this part, you also see what E = mc2 really means. (It’s more than saying “energy equals mass times the square of the speed of light.”)
Part IV: The General Theory of Relativity
The general theory of relativity is Einstein’s masterpiece. Its math is complicated (even Einstein needed help with it), but the idea behind it is simple. I don’t touch the math here. No need to. The ideas are beautiful, and you’ll be able to see how it all works.
I show you how Einstein’s ideas on time and space actually work and why Stephen Hawking says that black holes aren’t really completely black. You can also read Einstein’s theories about time travel. Finally, this part presents the major tests that NASA and other labs around the world have performed to check Einstein’s theories.
Part V: The Quantum and the Universe
Quantum physics started with one revolutionary paper that Einstein wrote during his miracle year. You’ll see why it was revolutionary and what it did to our understanding of reality. In this part, I also discuss Einstein’s famous letter to President Franklin Delano Roosevelt about the possibility of an atomic bomb and Einstein’s limited involvement with the bomb’s development. Finally, I explain the relevance of Einstein’s work and the important role it’s still playing today in the current theories of the universe and in the unification of all of physics, Einstein’s lifelong dream.
Part VI: The Part of Tens
This part is a staple in the For Dummies series. In this part, I explain ten views that Einstein held on religion and philosophy, and I give you short biographies of ten women who had an important influence on his life.
Icons Used in This Book
Throughout the book, you’ll notice icons in the margins that are designed to help you navigate the text. Here’s what they mean:
Our understanding of the physical world would be stagnant if scientists didn’t occasionally think about things in a new way. This icon alerts you that a stroke of genius is nearby.
I think all the information in this book is important, but some nuggets are worth putting into your mental filing cabinet for future reference. This icon points them out.
Einstein had a knack for explaining his theories using simple pictures and examples. I aspire to do the same in this book, and when you see this icon, you know a helpful hint is close at hand.
This icon points out information that goes beyond the basics — information that may be tough to digest or go into more detail than you need. If your gray matter isn’t up for the challenge, just skip past these paragraphs.