In search of time: journeys along a curious dimension

327 Pages·2009·2.45 MB·English

by  Dan Falk

In memory of my grandparents
Ignacy and Leonia Falk
Moshe Raviv and Dr. Rosalie Shein
That great mystery of TIME, were there
no other; the illimitable, silent,
never-resting thing called Time, rolling,
rushing on, swift, silent, like an
all-embracing ocean tide, on which we and
all the Universe swim like exhalations,
like apparitions which are, and then
are not: this is forever very literally
a miracle; a thing to strike us dumb,
– for we have no word to speak about it.
– Thomas Carlyle, Heroes and Hero Worship (1840)
Contents
Preface
Introduction
01 HEAVENLY CLOCKWORK
Time’s natural cycles
02 YEARS, MONTHS, DAYS
The quest for the perfect calendar
03 HOURS, MINUTES, SECONDS
Dissecting the day
04 IN TIME’S GRASP
Time and culture
05 THE PERSISTENCE OF MEMORY
A bridge across time
06 ISAAC’S TIME
Newton, Leibniz, and the arrow of time
07 ALBERT’S TIME
Spacetime, relativity, and quantum theory
08 BACK TO THE FUTURE
The science of time travel
09 IN THE BEGINNING
The search for the dawn of time
10 BEYOND THE BIG BANG
The frontiers of physics and the origin of time’s arrow
11 ALL THINGS MUST PASS
The ultimate fate of life, the universe, and everything
12 ILLUSION AND REALITY
Physics, philosophy, and the landscape of time
Notes
Bibliography
PREFACE
“You’re writing a book about what?”
Tell people you’re working on a book about time, and you get some interesting
reactions. Some look confused, or give a dismissive shrug – “What about time,” they ask,
as though there could hardly be enough interesting things to say about it to fill an entire
book. (“Doesn’t it just sort of tick by?”) Others seem to understand the appeal right
away, and wonder about particular topics. “Will you talk about time travel?” Yes, I
affirm – it gets a whole chapter to itself. (Even if time travel is impossible, I tell them, it
raises fascinating questions about the nature of time, space, and the laws of nature.)
Some people guess that I must be writing a “physics book” – highly technical, with
much talk of entropy and world lines and such. Not so, I assure them. Or at least not
“just” a physics book. My goal is to take a broader approach, tackling the enigma of
time from several different directions, each with its own perspective and insights – and
its own track record of successes and frustrations.
In fact, one has to approach time from many such angles, because no one discipline
has “the answer.” That fact was apparent whenever I glanced at the books that line the
shelves in my apartment. (There would, of course, be many trips to many libraries, but
one of the joys of building up a decent home collection is that quite a good chunk of
research can be done before one even braves the elements.) My first couple of shelves
cover the history and philosophy of science: this is where I reach for classics like
Bronowski and Boorstin and Gamow, a cluster of Carl Sagan titles, and more recent
works by Timothy Ferris and Dennis Danielson, to name a few. Beneath that, the
scientific biographies: Drake and Sobel on Galileo; Westfall and Gleick on Newton; Pais,
Fölsing, and Isaacson on Einstein; and other more narrowly focused titles on the
theories crafted by those great minds. Under that, a shelf of modern physics and
cosmology titles: Hawking, Weinberg, Greene, Davies, Rees, Krauss, and others. On the
next shelf, books on evolution and the nature of the human animal: Diamond, Tattersall,
Dawkins, Hauser. Below that, books on consciousness and the mind: Pinker, Penrose,
Dennett, Crick, Damasio, Edelman. Not to mention some very thorough books on clocks,
calendars, and timekeeping: Whitrow, Aveni, Landes, Duncan, Steel.
And time – well, time reaches across all of those fields. In fact, one of the challenges is
that each of these disciplines is to some degree intertwined with each of the others.
Interconnectedness is fine if you’re building a spider web, but it can actually hamper the
writing of a book, which demands a single flowing narrative – a story. To tell that story,
I’ve had to be selective. Where there was a choice between more science and more
philosophy, the science usually won out – not because the philosophy is uninteresting,
but merely because I found it to have less power to advance the story. (“What, no
Heidegger? No Bergson?” Sadly, no; we will have to make do with Plato, Aristotle,
Leibniz, McTaggart, and a handful of other key players.) Even within the sciences, there
is far too much current research to assess in a single volume; indeed, each of my twelve
chapters could easily have been a book in its own right, for an author so inclined. For
those who do wish to probe deeper, I hope that detailed notes and a full bibliography of
sources will aid in further reading. In the text itself, I have tried to make my selections
as carefully as possible, giving the most attention to those areas where science has made
the most tangible advances in recent years.
Research begins with books and journals and libraries, but it does not end there: over
the last few years, it has been my great privilege to meet with some of the deepest
thinkers of our time, in some cases for multiple interviews. “It will only take an hour,” I
would tell them, knowing full well that it would run much longer – and most of them
generously allowed me to keep asking away, microphone in hand. I am especially
grateful to Roger Penrose, Julian Barbour, David Deutsch, Lee Smolin, and Paul Davies;
their grasp of some of the most difficult problems in all of science is truly inspiring.
Many more scholars sat down with me and patiently described their research; others
guided me through laboratories, museum exhibits, and archeological sites. They are
named in the chapters ahead, and I am indebted to them all. (Most of these interviews
were conducted specifically for the present book, but I have also occasionally drawn on
research for various earlier projects, including several documentaries that I made for the
CBC Radio program Ideas.)
A number of people generously looked over portions of the manuscript at various
stages; Ivan Semeniuk, George Musser, and Natalie Munro made especially valuable
comments, while Elizabeth Howell was kind enough to read the entire text. (Of course,
any errors that remain are my responsibility alone.) I also benefited greatly from
discussions with James Robert Brown, Glenn Starkman, and Eugenie Scott.
The idea of writing a book about time had been in the back of my mind since the
completion of my first book, Universe on a T-Shirt: The Quest for the Theory of Everything
(2002). This book is by no means a sequel; the subject matter is, in general, quite
different. But certain key topics – special relativity, for example – do come up again; on
occasion, I refer the reader to more detailed explanations in the earlier book.
This project would not have come to fruition without the help of my agents, Don
Sedgwick and Shaun Bradley of the Transatlantic Literary Agency, and especially the
tireless work of my editor, Jenny Bradshaw at McClelland & Stewart, who helped hone
the manuscript into its finished form. I am also grateful to Stephanie Fysh for her copy
editing skills.
Where measurements crop up, I have once again primarily used metric units; I trust that
my U.S. readers will not have too much trouble with meters, kilometers, and the like.
On the other hand, I have used American spellings, which I hope will not alienate my
Canadian audience.
Readers’ comments are welcome; I can be reached through my website at
www.danfalk.ca.
INTRODUCTION
If we are aware of anything we are aware of the passage of time.
– J.R. Lucas, A Treatise on Time and Space
Time passes. Listen. Time passes.
– Dylan Thomas, “Under Milk Wood”
’ve completely solved the problem,” a young Albert Einstein said excitedly to
“I
his friend Michele Besso in May of 1905. “My solution was to analyze the
concept of time.”
Besso, a colleague of Einstein’s at the patent office in Bern, Switzerland, was the first
to be let in on the secret. A month later, the whole world would know. (Or at least,
those who read the Annalen der Physik on a regular basis. Another fourteen years would
pass before the scientist would become a household name.) Einstein’s groundbreaking
paper, the result of ten years of intense study and ingenious “thought experiments,” was
an attempt to reconcile Maxwell’s theory of electromagnetism with long-established
ideas about relative motion dating back to Galileo. It was an urgent problem that had
stumped the brightest minds of the day. The paper appeared under the innocuous title
“On the Electrodynamics of Moving Bodies” – and it changed everything. Suddenly time
was flexible, like rubber. Space and time were intimately linked. And simple words like
“now” seemed to lose their meaning entirely.
Einstein’s paper was shocking precisely because time is – or was supposed to be – so
simple. It still seems simple, more than a hundred years after Einstein’s breakthrough.
Time, after all, surrounds us. It envelops and defines our world; it echoes through our
every waking hour. Time is the very foundation of conscious experience.
Above all, time flows – or appears to flow. A river is the favorite metaphor; we
imagine time as a relentless stream, bringing the future toward us and carrying past
events off behind us. Equivalently, we can imagine time as a fixed landscape, with
ourselves sailing through it. A more modern metaphor is the movie projector: events can
be likened to frames of film, each illuminated ever so briefly in the light of an
instantaneous “now,” after which they recede into the past. Future events – later frames
– rush toward the lens, each to experience its own brief “now” in due course.
By either metaphor, time appears to flow in just one direction, leading from the fixed
events of the past toward an unknown future. It is unrelenting. No sooner have we
uttered the word “now” than another “now” has taken its place. That previous “now” is
lost to the past, gone forever. We cannot change the events of five seconds ago any
more than we can revisit the Battle of Hastings. The future, for its part, is hurtling
toward us, unstoppable. We may be unsure of what it will bring – but of its arrival there
can be no doubt.
If these statements seem obvious, perhaps even juvenile, it is a reflection of just how
deeply ingrained such feelings are. Young children quickly learn the meaning of words
like “yesterday,” “today,” and “tomorrow”; of “past,” “present,” and “future.” We think
of time as a commodity: we try to save time; we hate to waste time; we say we’ll make
time for some favorite activity. When we need to catch our breath, we call a time-out. We
say that time flies when we’re having fun and slows to a crawl at the dentist’s office –
but deep down we know better. We trust the keeping of “true” time to our clocks,
which, in a world peppered with semiconductor-laden gadgets, are more ubiquitous
than ever. Yet we also suspect that time would go by just as relentlessly even if no
clocks were around to mark its passing. As Aristotle remarked some 2,300 years ago,
“Even when it is dark, and we are not being affected through the body, if any process
goes on in the mind, immediately we think that some time has elapsed too.” Isaac
Newton suspected that time would flow just the same even if nothing were around to
mark its passing – but, as we will see, Newton does not have the last word on such
matters. Nor, for that matter, does Einstein: the problem that he “completely solved” in
1905 was just one of time’s many mysteries. Time has not yet given up all its secrets.
The great paradox of time is that it is at once intimately familiar and yet deeply
mysterious: nothing is more central and yet so remote. To be human is to be aware of
the passage of time; no concept lies closer to the core of our consciousness. Yet who can
say just what time is? It is thoroughly intangible. We cannot see, hear, smell, taste, or
touch it. Yet we do feel it. Or at least we think we feel it. This, as we shall see, is not just
wordplay: scientists and philosophers continue to debate just what we mean when we
utter a simple phrase like “time passes.”
Time is linked to change. At one time, we observe this; at a later time, we observe
that; and we associate that change with time’s passing. No wonder that time is
sometimes defined as “nature’s way of keeping everything from happening at once.”
And yet to equate time with change seems to be missing something. The passage of time
seems, somehow, to be more fundamental. No wonder poets, writers, philosophers, and