Jim Al‑Khalili on The World According to Physics

Jim Al‑Khalili on The World According to Physics

By Jim Al-Khalili

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Shining a light on the most profound insights revealed by modern physics, Jim AlKhalili invites us all to understand what this crucially important science tells us about the universe and the nature of reality itself. Al‑​​​​​​​Khalili begins by introducing the fundamental concepts of space, time, energy, and matter, and then describes the three pillars of modern physics—quantum theory, relativity, and thermodynamics—showing how all three must come together if we are ever to have a full understanding of reality.

This smaller format book – almost pocket-sized – is interesting. What’s the idea behind it?

JA-K: If you look at the popular science shelves in bookshops today, they seem full of great tomes that, while thorough, beautifully written and aimed at a non-specialist audience, are nevertheless rather hefty. I know how much more my rucksack weighs when I am carrying one around with me. In contrast, I loved Carlo Rovelli’s Seven Brief Lessons on Physics, which also has this attractive compact, smaller format. I think of The World According to Physics as being in a similar style but giving the reader a little more information than Rovelli did, and I try to say something about the latest theories and ideas at the very limits of what we currently know.

Your previous book also happens to be your first novel, Sunfall—a scifi techno-thriller that the writer Stephen Baxter referred to as “The Day After Tomorrow meets Neuromancer.” Given its success—in the UK at least—why have you gone back to writing non-fiction?

JA-K: Writing Sunfall was a fantastic experience, but the project took three years from conception to publication and fiction writing proved to be an enjoyable yet steep learning curve. Over the course of the writing and several edits I picked up a lot of story-telling skills that naturally I don’t want to go to waste. But at the same time, there has been this growing urge inside me to write about some of the exciting new ideas in physics, particularly since there is currently a big shift in thinking among theoretical physicists – not that we have made any particularly exciting breakthroughs – we’re still waiting for the next Einstein to come along – but rather that our attitudes towards the status of our current theories in fundamental physics and our understanding of the nature of reality is starting to shift.

Many academic physicists-turned popularisers have published mass-market books on their latest ideas in cosmology or quantum physics, so isn’t your book joining a crowded market?

JA-K: I really believe this book is different. I refer to it as my ode to physics. You can think of our scientific knowledge of the workings of the universe as a vast island – there are still unexplored areas inland, but beyond its shores is still a vast ocean of the unknown. As we increase our understanding, so the shoreline extends outwards and the island grows in size. Many books on physics take the reader on a journey of exploration around the island, explaining what we know and telling the stories of how the island has grown over the years. I wanted instead to take my readers on a field trip around the shoreline itself, maybe taking off our shoes and socks, rolling up our trouser legs and wading out into the unknown to explore what might be under the surface waiting to be discovered.

I also very much wanted this book to be a personal journey – to infect the reader with my own love of the physics I have spent four decades studying and thinking about and to try to find new ways of explaining it to others. There are even occasions when I get rather polemical in the book, not holding back on my views about the direction physics research has taken in recent years. This is particularly the case when it comes to the meaning of quantum mechanics. Too many physicists use their books as a means of expounding one worldview at the expense of others, turning science into an ideological belief, almost like a religion. That is not what science is about. I state at the beginning of the book that I do not want to get embroiled in philosophical arguments or metaphysics – the real world is out there and it is the job of physicists to try and understand it.

You say you get polemical in the book, so then are you also expounding a particular ideological stance?

JA-K: Hmmm… well, I do try hard to be neutral, but yes, every now and then, one of my bugbears surfaces and have to stop myself from descending into a rant. But it’s sort of fun – it’s as though my foray into fiction writing has released me from the rigid constraints of explaining stuff in a particular traditional way. So, I try to find new and fresh analogies or ways of looking at deep problems, such as what is the nature of space? Does it exist if it is completely empty? And do we really understand what time is? Such questions are not new, but I hope that by being as clear as possible in my explanations and descriptions, this book will help readers better understand concepts they have only vaguely heard of. Of course, a lay person is not going to understand the intricacies of quantum field theory or cosmology by reading this small book, but he or she will, I hope, be infected with my enthusiasm and at least appreciate what some of the fundamental issues are: what we are confident about and what we are not. In true Rumsfeldian style I wanted to layout the most intriguing known knowns, known unknowns and even make some guesses at the unknown unknowns.

So, can you give a summary of what is currently so exciting in research at the forefront of physics?

Well, there is so much going on that I cannot include it all in the book, let alone in this brief answer to your question. But for me it’s all about the big picture – that we no longer think we are nearing the end of physics. At the beginning of the 21st century there was this feeling that we were getting close to that holy grail of physics: a theory of everything. The leading candidate was (well, it still is I suppose) called superstring theory, or M-theory, and it was regarded as the leading candidate theory that would give us a unified picture of quantum mechanics and general relativity (Einstein’s theory of gravity). Now, we’re not so sure. Many physicists, including me, feel that a new approach is needed, and it is one that brings together lots of ideas in modern physics from different fields. It’s these ideas that I explore with a light touch in the book. For example, it is looking increasingly likely that to reach a final theory we will have to combine not just quantum mechanics and relativity, but thermodynamics and information theory too. In fact, making progress might even require us to find the ‘correct’ interpretation of quantum mechanics – something we have been arguing about for almost a century. Some concepts may sound esoteric and abstract, such as entropy, entanglement or inflation, and some may have reached popular culture even though we physicists don’t yet fully understand them, like dark matter or dark energy. What is most exciting for me is that there is still so much to explore along the shoreline between the known and unknown.

Jim Al-Khalili is professor of physics at the University of Surrey. He is one of Britain’s best-known science communicators and has written numerous books, including Quantum: A Guide for the PerplexedThe House of Wisdom: How Arabic Science Saved Ancient Knowledge and Gave Us the Renaissance; and Life on the Edge: The Coming of Age of Quantum Biology. He is a fellow of the Royal Society and lives in Southsea, England. Twitter @jimalkhalili