Coming of Age in the Milky Way (55 page)
Read Coming of Age in the Milky Way Online
Authors: Timothy Ferris
Tags: #Science, #Philosophy, #Space and time, #Cosmology, #Science - History, #Astronomy, #Metaphysics, #History
Imaginary time in Hawking’s view was the once and future time, and time as we know it but the broken-symmetry shadow of that original time. When a hand calculator cries “error” upon being asked the value of the square root of —1, it is telling us, in its way, that it belongs to
this
universe, and knows not how to inquire into the universe as it was prior to the moment of genesis. And that is the state of all science, until we have the tools in hand to explore the very different regime that pertained when time began.
Another quantum approach to genesis, championed by John Wheeler, emphasized the quantization of space itself. Just as matter and energy are made of quanta, went this line of reasoning, so space itself ought to be quantized at its foundations. Wheeler liked to compare quantum space to the sea: Viewed from orbit, the surface of the ocean looks smooth, but if we set out in a rowboat on the surface, “we see foam and froth and breaking waves. And that foam and froth is how we picture the structure of space down at the very smallest scales.”
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In the present-day universe, the foamy structure of space manifests itself in the constant blooming forth of virtual particles. In the extremely early universe—meaning prior to the Planck time—space would have been a very rough sea indeed, and its storm-tossed quantum flux might have dominated all particle interactions. How, here, do we find our bearings?
Wheeler—an elder statesman who learned his science from Einstein and Bohr and in turn educated a whole generation of physicists—thought the answer lay in spacetime geometry: “What else is there out of which to build a particle except geometry itself?”
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he asked. Wheeler compared the quantum flux of the early universe to a complicated sailor’s knot of a kind that looks impossibly tangled, yet will fall apart if one can find the end of the rope and give it a tug in the right way. The knot in his simile is the hyperdimensional geometry of the original universe, the untangled rope the universe we inhabit today. Penrose had said, “I do not believe that a real understanding of the nature of elementary partides
can ever be achieved without a simultaneous deeper understanding of the nature of spacetime itself.”
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For Wheeler, this was true of the universe as a whole:
“Space is a continuum.” So bygone decades supposed from the start when they asked, “Why does space have three dimensions?” We, today, ask instead, “How does the world manage to give the impression it has three dimensions?” How can there be any such thing as a spacetime continuum except in books? How else can we look at “space” and “dimensionality” except as approximate words for an underpinning, a substrate, a “pre-geometry,” that has no such property as dimension?
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To answer such questions, Wheeler argued, science would somehow have to bootstrap itself into a new realm, a world of “law without law,” in which, as taught by the quantum indeterminacy principle, the answer depends upon the question asked. Wheeler recalled being the subject in a game of twenty questions. He left the room for a period during which the answer was to be decided upon by the other players, then returned and started asking questions. The answers were progressively slower in coming, until Wheeler finally guessed, “Cloud,” and was told, to general amusement, that he was right. When his friends stopped laughing they explained that they had been playing a trick on Wheeler: There had originally
been
no right answer; his friends had agreed to formulate their answers so that each would be consistent with the answers given to his previous questions. “What is the symbolism of the story?” asked Wheeler.
The world, we once believed, exists “out there” independent of any act of observation. The electron in the atom we once considered to have at each moment a definite position and a definite momentum. I, entering, thought the room contained a definite word. In actuality the word was developed step by step through the questions I raised, as the information about the electron is brought into being by experiment that the observer chooses to make; that is, by the kind of registering equipment that he puts into place. Had I asked different questions or the same questions in a different order I would have ended up with a different word as the experimenter would have ended up with a different story for the doings of the
electron. … In the game no word is a word until that word is promoted to reality by the choice of questions asked and answers given. In the real world of quantum physics,
no elementary phenomenon is a phenomenon until it is a recorded phenomenon
.
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We are left, then, with an image of genesis as a soundless and insubstantial castle, where our eyes cast innovative, Homeric beams and the only voices are our own. Having ushered ourselves in and having reverently and diligently done our scientific homework, we ask, as best we can frame the question, how creation came to be. The answer comes back, resounding through vaulted chambers where mind and cosmos meet. It is an echo.
*
“Initial” conditions in cosmology are seldom absolutely initial, since nobody yet knows how to calculate the state of matter and space-time prior to the Planck time, which culminated at about 10
−43
second ABT. One instead designates as “initial” some point subsequent to the Planck epoch. For most purposes this is regarded as quite initial enough.
*
The sphere can be in many dimensions; that is another question, addressed by the supersymmetry theories, which did not as yet prescribe a timetable describing when the young universe allegedly collapsed its ten or so dimensions into three of space and one of time.
*
Inflation theory indicates that the universe is many billions of times greater in volume than had been estimated in the old big bang model. The
observable
universe, however, is thought to constitute but a fraction of the universe as a whole: Its limits are determined less by space than by time, in that we can see only those events the light from which has had time to reach Earth. If, for instance, the first stars began to shine thirteen billion years ago, then no observer will see stars any farther than thirteen billion light-years away, regardless of how large the universe as a whole may be.
M
IND
AND
M
ATTER
Life, like a dome of many-colored glass, Stains the white radiance of Eternity.
—Shelley
A sad spectacle. If they be inhabited, what a scope for misery and folly. If they not be inhabited, what a waste of space.
—Thomas Carlyle
T
he scientific developments we have been discussing in this book have worked, however inadvertently, to implicate and involve our species in the wider universe. Astronomy, in shattering the crystalline spheres that had been said to seal off the earth from the aethereal realms above the moon, placed us
in
the universe. Quantum physics cracked the metaphorical pane of glass that had been assumed to separate the detached observer from the observed world; we are, we found, unavoidably entangled in that which we study. Astrophysics, in determining that matter is the same everywhere and that it everywhere obeys the same rules, laid bare a cosmic unity that extends from nuclear fusion in stars to the chemistry of life. Darwinian evolution, in indicating that all species of earthly life are related and that all arose from ordinary matter, made it clear that there is no wall dividing us from our fellow creatures
on Earth, or from the planet that gave us all life—that we are such stuff as worlds are made of.
The conviction that we are in some sense at one with the universe had of course been promulgated many times before, in other spheres of thought. Yahweh fashioned Adam out of dust; Heraclitus the Greek wrote that “all things are one;” Lao-tzu in China depicted man and nature alike as ruled by a single principle (“I call it the Tao”); and a belief in the unity of humankind with the cosmos was widespread among preliterate peoples, as evidenced by the Suquamish Indian chief Seattle, who declared on his deathbed that “all things are connected, like the blood which unites one family. It is all like one family, I tell you.” But there is something striking about the fact that the same general view has arisen from sciences that pride themselves on their clearheaded pursuit of objective, empirical fact. From the chromosome charts and fossil records that chart the interrelatedness of all living things on Earth to the similarity of the cosmic chemical abundance to that of terrestrial biota, we find indications that we really are a part of the universe at large.
This scientific verification of our involvement in the workings of the cosmos has of course many implications. One of them—the subject of this chapter—is that, if intelligent life has evolved on this planet, it may have also done so elsewhere.
*
Darwin’s theory of evolution, though it does not explain away the ancient conundrum of why there is such a thing as life, does make it clear that life may arise from ordinary matter and evolve into an “intelligent” form, at least on an Earthlike planet orbiting a sunlike star. As there are plenty of sunlike stars (over ten billion of them in the Milky Way galaxy alone), and, presumably, more than a few Earthlike planets, we can speculate that we are not the only species ever to have studied the universe and wondered about our role in it.
Our comprehension of the relationship between mind and the universe may depend upon whether we can make contact with another intelligent species with which to compare ourselves. Seldom has science done very well at studying phenomena of which
but a single example was available: Newton’s and Einstein’s laws would have been far more difficult—perhaps impossible—to formulate had there been only one planet to test them against, and it is often said that the central problem of cosmology itself is that we have but a single universe to examine. (The discovery of cosmic evolution eases this difficulty, by proffering for our consideration the very different state of the universe during the first moments of cosmic evolution.) The question of extraterrestrial life, then, goes beyond such issues as whether we are alone in the universe or may look forward to cosmic companionship or need fear alien invasion; it is also a way of examining ourselves and our relationship to the rest of nature.
Though much here is new, recent interest in extraterrestrial life can be viewed as resulting from the latest upturn in the fortunes of materialism, the philosophical doctrine that events can be explained solely in terms of material interactions, without recourse to insubstantial conceptions such as that of spirit. Darwinism engendered a new respect for the potential of ordinary matter: A lump of mud in a puddle of rainwater begins to look quite magical, if one appreciates that its like once reared itself up into the whole panoply of earthly life, including that possessed by the individual who contemplates the mud. No longer could a thinking person, mindful that his or her ancestry stretches back through the mammals to the fishes to the amino acids and sugars of prebiotic matter, readily agree with Martin Luther that the earth is but “defiled and noxious,” or accept the verdict of the Christian Science service that “there is no life, truth, substance, nor intelligence in matter.”
Historically, materialists have been inclined to imagine that there is life on other worlds. Metrodorus the atomist wrote in the fourth century
B.C
. that “to consider the earth as the only populated world in infinite space is as absurd as to assert that in an entire field sown with millet only one grain will grow.”
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Five centuries later, Lucretius the Epicurean proposed that “there are infinite worlds both like and unlike this world of ours.”
2
The Roman Catholic Church, convinced that humans are essentially immaterial spirits, felt threatened by the materialistic point of view: When Giordano Bruno, the Renaissance doyen of pop mysticism, asserted that matter “is in truth all nature and the mother of all living things,”
3
and declared that God “is glorified not in one, but in countless suns;
not in a single earth, but in a thousand, I say, in an infinity of worlds,”
4
he was tied to an iron stake and burned alive, on February 19, 1600, in the Piazza Campo dei Fiori in Rome.
Nevertheless, as science ascended so did materialism, and with it the belief in a plurality of populated worlds. In England in 1638, a Protestant clergyman named John Wilkins published a book proposing that the moon was habitable. Descartes, whose theory of cosmic vortices foreshadowed aspects of Newton’s universal gravitation, wondered whether “elsewhere there exist innumerable other creatures of higher quality than ourselves.”
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But no writer did more to infuse the conception of a diverse, fertile universe with a sense of delight than the young French Cartesian Bernard de Fontenelle, whose
Conversations on the Plurality of Worlds
was published in 1686 and has enchanted readers ever since. The book takes the form of a dialogue between Fontenelle and a beautiful, unnamed countess with whom he walks in the gardens each evening at twilight, discussing the stars as they wink into view in the darkening sky. “Who can think long of the moon and stars, in the company of a pretty woman!” Fontenelle exclaims, but he soon gets down to business. “The earth swarms with inhabitants,” he tells the countess. “Why then should nature, which is fruitful to an excess here, be so very barren in the rest of the planets?”
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The moon, he thinks, may
be
inhabited, but he does not know by what sort of beings: “Put the case that we ourselves inhabited the moon, and were not men, but rational creatures; could we imagine, do you think, such fantastical people upon the earth, as mankind is?”
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