Knocking on Heaven's Door - Lisa Randall [3]
The last few years have provided me with some unique experiences and with conversations that have taught me a great deal, and I want to share these as launching points to explore some important ideas. Although I’m not a specialist in all the areas I cover and there is not enough space to do them all full justice, my hope is that this book will lead readers in more productive directions, while elucidating some exciting new developments along the way. It should also help readers identify the most reliable sources of scientific information—or misinformation—when they look for further answers in the future. Some of the ideas this book presents might appear very basic, but a more thorough understanding of the reasoning that underlies modern science will help pave a better approach both to research and to important issues the modern world currently faces.
In this era of movie prequels, you can think of Knocking on Heaven’s Door as the origin story to my previous book, Warped Passages, combined with an update of where we are now and what we are anticipating. It fills in the gaps—going over the basics about science that underlie new ideas and new discoveries—and explains why we’re on the edge of our seats waiting for new data to emerge.
The book alternates between details of science being done today and reflections on the underlying themes and concepts that are integral to science but that are useful for understanding the broader world as well. The first part of the book, Chapters 11 and 12 in the second part, Chapters 15 and 18 in the third part, and the final (Roundup) part are more about scientific thinking, whereas the remaining chapters focus more on physics—where we are today and how we got there. In some respects, it is two books in one—but books that are best read together. Modern physics might appear to some to be too far removed from our daily lives to be relevant or even readily comprehensible, but an appreciation of the philosophical and methodological underpinnings that guide our thinking should clarify both the science and the relevance of scientific thinking—as we’ll see in many examples. Conversely, one will only fully grasp the basic elements of scientific thinking with some actual science to ground the ideas. Readers with a greater taste for one or the other might choose to skim or skip one of the courses, but the two together make for a well-balanced meal.
A key refrain throughout the book will be the notion of scale. The laws of physics provide a consistent framework for how established theoretical and physical descriptions fit together into a coherent whole, from the infinitesimal lengths currently explored at the LHC to the enormous size of the entire cosmos.2 The rubric of scale is critical to our thinking, as well as to the specific facts and ideas we will encounter. Established scientific theories apply to accessible scales. But those theories become absorbed in increasingly precise and more fundamental ones as we add newly gained knowledge from previously unexplored distances—small or large. The first chapter focuses on the defining element of scale, explaining how categorizing by length is essential to physics and to the way in which new scientific developments build upon prior ones.
The first part also presents and contrasts different ways of approaching knowledge. Ask people what they think about when they think about science, and the answers are likely to be as varied as the individuals you ask. Some will insist on rigid, immutable statements about the physical world. Others will define it as a set of principles that are