The beauty of physics is summed up in one simple fact: a child can ask questions that no professor can answer. Indeed, searching out the “big questions” in physics is rather like looking for hay in a haystack. When it comes to physics, it appears there is no such thing as a small question. A seemingly insignificant query or experiment can often lead to profound insight.
It is a short step, for instance, from asking whether the laws of physics can ever change or be broken to wondering whether there is room for a creator. It doesn’t stop there, either. Physics tells us a creator need not be divine; it could be that we live nested within an infinite number of universes, each created by a species only slightly more intelligent than its greatest creation. We may even be destined to become creators of a universe ourselves.
With such big issues at its fingertips, it is small wonder that the most iconic scientists of our generation have been immersed in physics. Albert Einstein became a celebrity almost overnight when his theory of relativity changed our conception of the universe. Carl Sagan’s TV program Cosmos remains the most-watched series on public television. Richard Feynman’s cool appraisal of the physics behind the Challenger shuttle disaster revealed how powerful a working knowledge of the subject can be. Stephen Hawking’s work, laid out in his bestseller A Brief History of Time, created a thirst for scientific insight in people who had never given the sciences a thought. Only the discoverers of DNA, perhaps, can stand alongside these giants.
And yet, it has to be said, people also tend to recoil from physics. If I mention in casual conversation that I am a physicist by training, the announcement is met with a strange mixture of admiration and embarrassment. While expressing awe at anyone who would attempt to understand the universe, many also seem to consider the subject completely beyond them. “Oh,” they say, “I never did understand physics.”
If you recognize yourself in that statement, then hopefully this book will change your perspective. Perhaps the best-kept secret in physics is that there is too much there for anyone to understand. This is not a problem, however: this is the root of its allure.
Physics has so much to explore that, once it captures your imagination, it is hard to tear yourself away. The clock on the wall becomes a tease about the elusive nature of time. Sunshine is what results from a beautiful, intricate dance of particles known as nuclear fusion. When raindrops fall to the ground, you can ask yourself a simple “why?” Exploring the answer will keep you occupied through the longest thunderstorm. The way a sunflower grows speaks of the conservation of energy and how the nature of light has shaped life on Earth. Go a step further and ask what light is, and you are peering into something widely considered to be the deepest mystery in nature.
This book is designed to show how simple questions lead to some of the most profound discoveries that humanity has ever made. They encompass the physics you probably didn’t learn in class: the real point of the subject; its implications; what we understand about the universe—and what we don’t. Carl Sagan once said, “Somewhere, something incredible is waiting to be known.” Hopefully, that process can begin here.