Physics is often referred to as the mother of all the Sciences because it explores natural laws that underly all physical phenomena at the most fundamental level. If physics were a person, it would perhaps speak in the words of one of the most famous physicists, Albert Einstein: “I want to know God's thoughts — the rest are mere details.”
Over the past centuries, we have learned a great deal about the physical world. As physics expands our understanding of the universe, one needs more time and effort to acquire a broad perspective of the field — while having one’s imagination constantly stretched to its limits. Yet, as the impact of physics on society also expands — from applications in space, electronics, to information technologies — it becomes ever more important that this knowledge base of the fundamental sciences is widely shared and appreciated.
This electronic book is a unique project that has taken several years to complete. It leverages the latest technologies to present a modern and mature qualitative exposition of physics. Anyone with a high school degree is capable of accessing the material thanks to the 70+ “applets” that replace the traditional role played by mathematical equations. Applets are small apps that run interactively within the ebook and make sophisticated ideas accessible without requiring extensive background in mathematics. In many of the cases, these applets consist of fully developed numerical simulations of physics equations that run in real time within the ebook!
So far, I believe ebooks have not lived up to their full potential in that they have been loose unions of traditional text and interactive/multimedia content. This ebook breaks new ground as it is written from the bottom up with the integration of the latest interactive visual tools directly into the narrative. Prior to these technologies, it would be impossible to imagine tackling physics at this level of sophistication while targeting a general audience. Indeed, Apple’s powerful iBooks platform is currently the only one that makes this possible. I hope this effort opens up a whole new direction in electronic book development that extends the traditional book — instead of trying to replace the wonderful and time tested technologies of ink and paper.
I’ll end with another of my favorite quotes, this one by Enrico Fermi: “Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level.” I hope this ebook manages to confuse you at a higher level.
This chapter provides the conceptual scaffolding for understanding the ideas discussed in this book. In a few broad strokes it sketches out the basic axiomatic assumptions and outlines a set of beliefs that guides the process of discovery in theoretical physics.
Quantum physics is, arguably, the greatest success story of contemporary science. Yet, it remains one of the most counterintuitive theories that bewildered the minds of the greatest 20th century thinkers. It continues to baffle us today, even while we apply its ideas in modern technology. This chapter outlines the main principles of quantum theory, describes what it helps us understand about the microscopic world, and discusses the puzzles to which it leads.
Black holes are the most extreme phenomena in the universe. They push the limits of our imagination and drive our formulations of the laws of nature to their breaking point. This chapter discusses relativity —both special and general — which allows us to understand a cornucopia of puzzles associated with black holes.
Understanding the cosmos is arguably the most profound endeavor in physics. It leads to questions about the nature of space and time, the origins of all matter and energy, the ultimate fate of the universe, and grand coincidences associated with our presence in this world. In this chapter, we explore all these topics and the puzzles they lead to.
String theory may be viewed as a framework for exploring new exotic ideas on the frontier of theoretical physics. At its heart, the subject aims to reconcile quantum mechanics with gravity; it also attempts to unify and complete the Standard Model of particle physics at short length scales. In this chapter, we give a brief overview of the main premise of string theory, and then focus on several of the key ideas that it leads to.