B00B7H7M2E EBOK (43 page)

There are those, including Hawking, who like to quote the dictum of quantum theory that what is not forbidden can and will occur. It isn’t surprising, then, to hear Hawking say that under high enough magnification the quantum fluctuation becomes such that there’s a probability we’ll find it doing ‘anything’. The cosmic balloon might develop a minuscule bulge in it, and that in turn could become another tiny balloon,
attached
to the parent balloon by a narrow neck. The neck is a wormhole; the balloon is a baby universe.

It hardly needs saying that there are no experimental or observational data to support this speculative theory. Hawking is pessimistic about any tests revealing the existence of wormholes. No one expects ever to find direct observational evidence, for wormholes exist only in imaginary time, and even if that were not the case, their size rules out seeing them.

However, the newborn universe attached to this umbilical cord need not continue to exist only in imaginary time or stay small. If the theory is correct, our own presumably didn’t. The new universe might end up something like ours, extending many billions of light years. Of course, with one universe spawning many more universes, and those many more yet, there must be a never-ending labyrinth of them. Successfully measuring the dimensions of our own universe would give us no clue what portion of the whole this represents.

These brief introductions to four models of the universe and beyond supply plenty of material for speculation, but the images described here do not allow us to say that the universe
is
or even
may be
shaped like a horn, or a sphere, or a pea, or a cone, or a parabola. These shapes are the closest theorists can come to representing in ordinary descriptive language what is only completely describable in the language of mathematics.

Einstein said that the gift of fantasy was essential to his work. Certainly these intellectual descendants of his who speculate about how the universe fits into a larger context have that gift. In one sense they are all remarkably inventive yarn-spinners. Yet their proposals are not science fiction. This is fantasy tethered to the known world by hefty guy-wires of mathematical equations. Nevertheless, no one knows whether these theories will be remembered only as curiosities, like Kepler’s linking the planetary orbits to melodic lines, or whether like his laws of
planetary
motion they might turn out to be among the most significant advances in all the history of science. With present technology, it isn’t even possible to make an educated guess which it will be.

EPILOGUE

Far and few, far and few

Are the lands where the Jumblies live.

Their heads are green, and their hands are blue,

And they went to sea in a sieve.

from ‘The Jumblies’ by Edward Lear

IN THE SPRING
of 1997, one of the most breathtaking views of the Hale-Bopp comet was from the Lofoten Islands off the coast of Norway, north of the Arctic Circle. Fog often shrouds this remote, jagged land and seascape. But that spring when the mists cleared they revealed the comet suspended against a background of stars above an eerie billowing drapery of Northern Lights – all reflected in the water. Every now and then a streak of colour shot into the sky, soared in an arc over the comet, and disappeared among the stars.

Over the comet? Among the stars? So it might have seemed to those watching from the Lofoten Islands had they not known that the stars above them were much further away than the comet, not friendly sparkles but enormous, blazing infernos. The comet and its tail, that we could hide with our thumb held
at
arm’s length . . . experts had told us that that was 50–60 million miles of light, dwarfing the earth. The Northern Lights are on our own doorstep by comparison and do not come anywhere near soaring in an arc ‘over the comet’.

In these chapters we’ve followed human beings as they’ve pondered the magnificent enigma of that same sky for thousands of years with wonder, loneliness, and, as Galileo put it, ‘with intense longing’. Men and women have written poems, sung about its beauty, worshipped it, found evidence there of a Creator God or no God at all, scrutinized it with telescopes, ventured a little way out. And, with remarkable success, they’ve measured the universe.

All tamed then? Is that how the story ends? The great mystery reduced to numbers and graphs?

My favourite analogy for the progress of science is one I learned from Herman Bondi: our scientific knowledge is an island – an island of ‘What We Know’ – that lies in the midst of a vast sea of the Unknown. As long as human beings have lived on the earth, they have been adding to that island, and the labour continues still at a frenzied pace. That just seems to be something humans
do
. They add to their island, as surely as squirrels gather nuts. So the island of What We Know grows larger and larger, spreading in all directions. Sometimes a cliff crumbles back into the sea, or we forfeit acreage in a hurricane, or a tidal wave sweeps away a promontory . . . and someone cautions Mr Elmendorf that a large portion of the land could shift alarmingly any day. But the island does grow inexorably, and it is astounding how much we now know! Unless the Sea of the Unknown is infinite, it surely must be shrinking.

Perhaps. But we notice something strange happening. Every time we add to the island of What We Know, the coastline – the line where we run up against the Unknown – grows longer. There are more and more locations where we encounter what we
don’t
know.

In this book we’ve witnessed the living out of this parable
over
the course of more than two millennia. We’ve seen evidence of it in the burgeoning cast of characters as the story progressed. In the early chapters, though these dealt with very long time spans, there were only a handful of men on the water’s edge. We were able to enjoy leisurely biographical sketches of them. Later chapters discussed much shorter periods of time, but the number of persons involved grew. The biographies were shorter and more numerous. In chapters 7 and 8 it was barely possible to list all the names of those building on to the headlands, peering at the horizon, and putting out to sea in both small craft and exceedingly expensive contraptions.

The increase in sheer numbers is, of course, partly due to a growing world population and the availability of university-level education. The progression, as it manifests itself in this book, is also somewhat explained by the fact that the more hindsight we have, the better we’re able to discern which were the significant insights and discoveries. Had we lived at the time of Copernicus, our discussion of contemporary astronomy would have had to include many more researchers, books and ideas than those mentioned in
Chapter 2
, and we might have chosen the wrong persons to profile. Four hundred years later it’s easy to tell what work in the 16th century was leading to a dead end and what opened a door to the future, and to see that Copernicus dwarfed his contemporaries.

But the expanding number of people and projects also bears witness to the fact that the coast of our island is growing. There is more room on the shoreline every day, and people are eager to fill it. We’re aware of so many more questions than our ancestors thought to ask, so many more areas that need investigation, so many more trails of evidence to be followed, anomalous details to make sense of, complexity to be unravelled, paradoxes to get our stubbornly intuitive minds around. Ptolemy, Copernicus, Galileo had no idea how mysterious this universe would turn out to be!

If the mystery isn’t lost, perhaps the simplicity and single-mindedness of earlier science is? Has the coastline become too long? Too many names, too many teams, too much specialization, too many directions to go? Has it become nothing else but the exponential accumulation of arcane knowledge – more than anyone can ever fit together in a coherent picture?

Nature herself has made certain it isn’t like that. We have learned that this reaching into the unknown, while it certainly encounters bewildering complications, always seems to grasp simplicity. The story appears to work backwards: at the end of the Hellenistic era, Ptolemy’s explanation of the heavens was as complicated as the mechanics of Disneyland. Copernicus’s description was a move towards simplicity. Kepler’s more so. Newton’s understanding was even more concise. Einstein’s, simpler yet. Observations like those Galileo made with his telescope and those we are making with the Hubble telescope can be puzzling, can seem almost beyond possibility of explanation. Human genius searches for and often finds the beautiful symmetry that underlies and makes sense of the confusion.

We began this book by measuring a windmill, but nine chapters have shown us something subtly different from what my father, my brother and I did that day in Texas. We measured the windmill in an old-fashioned way, with hindsight, if you will. We knew that there were ways to measure it more directly, that its height was a number that could be found out precisely. We were not pushing our mathematics and technology to the limits by any means. The men and women in this saga of cosmic measurement
have
been doing that and more.

It is a particular fascination of mine to try to put myself in the place of those in earlier centuries who
didn’t know what was coming next
. When we try to do this with the characters in this book, we are immediately reminded that at every stage of history, it was impossible for them to anticipate that what they could not do, their descendants
would
be able to do. Perhaps that’s why they were so often willing to go out on a limb, to
build
on shaky assumptions, to fashion a precarious ladder, to put their faith in ill-understood calibrators . . . because they had no way of knowing whether it ever would be possible to stand on firmer ground.

Whatever the motivations, we have been an impatient and irrepressible lot . . . measuring the parallax of Mars in full knowledge that the uncertainty of the measurement would imperil the results . . . scrambling up the scaffolding to a giant telescope before it was safely braced . . . battling to measure stellar parallax long before the technological moment arrived . . . grasping at Cepheids as handholds into the universe without knowing the distance to even one of them . . . devising a formula for omega while our understanding of what goes into the formula is still worse than vague. In each epoch we have hoped that the impossible would later become easy. But we couldn’t know, and we weren’t willing to wait.

It might all have been less messy had we waited. It might in fact have more resembled what we would like to think the history of cosmic measurement has been. Many accounts give the impression that after Copernicus we ‘knew’ the arrangement of the solar system. After Cassini we ‘had’ the measurements to the planets and ‘were sure of’ the length of the base line afforded by Earth’s orbit. In the 1950s we finally ‘discovered’ the size of the universe. It all moved by solid increments.

It hasn’t been like that. We have groped, guessed, doubted one another, made missteps, built the rungs of the ladder too close together, felt it buckle beneath our feet, fought for a hold. In this book we’ve ended our tale not on the coastline of the island of What We Know but on jetties built far out from shore . . . even on small, frail craft almost out of sight of land . . . at sea in a sieve. But that is nothing new. Indeed that is precisely where we have been in every chapter of this book, at every stage of this history.

The nature we’ve striven to understand has fought back by showing us our place. Sometimes that’s been a severe comeup
pance
, but it isn’t all bad news. To be sure, human beings are not the centre of the universe, and they are not large by universal standards, but they aren’t small either. Not the largest nor the smallest things around by a long shot. Draw a line from the smallest to the largest, and from our vantage point the ends of the line stretch in both directions to numbers beyond our ability to comprehend. As far as we can tell, we are somewhere near the midpoint of the line, approximately equidistant from the ends as we now perceive them.

There’s another way to measure us. If we draw a line from the simplest to the most complex, we are not sitting at the midpoint. We’re at one end. We are the most complex thing we have yet discovered in the universe. The human mind is still largely unexplained. The human situation is unfathomable. How paradoxical that with motives and longings and limitations rooted in the confusion of who we are, we probe the depths and heights, often with complex mathematics as our only tool . . . on a quest to discover not more complication, but simplicity!

‘Who hath stretched a measuring line across it?’ God taunts Job in the scriptures. Shall we raise a timid hand and venture, ‘I think . . . well . . . actually . . .
we
have’? Maybe. Maybe not. For it is still a great mystery how large our island is – this treasured, hard-won, incalculably valuable, perhaps tiny island of human knowledge – compared with the sea.

ADDENDUM (2012)