A twenty-year crossword puzzle
Hugh Lawson-Tancred
WRINKLES IN TIME by George Smoot and Keay Davidson Little Brown, £18.99, pp. 321
are invited to imagine an infinites- We imal pinpoint of limitless temperature and energy concentration which instantaneous- ly multiplies itself by a colossal factor to the size of a small melon some ten cen- timetres in diameter, whereafter it contin- ues to expand at a speed gracefully declining from that of light for approxi- mately 15 billion years. This remarkable event does not occur either in space or in time but is rather to be thought of as constitutive of both. The content of the explosive item is, initially, a wholly indiscriminate plasma of matter and energy from which all local features have been erased by the extraordinary rapidity of its early inflationary growth. For the first 300,000 years of its existence, this soup crystallised itself into the fundamental par- ticles of all matter and energy which, how- ever, persist in indissoluble immersion. Then, at just that instant at which the tem- perature of the whole reaches a mere 3,000 degrees, the particles of matter and radia- tion decouple, and in a cataclysmic efful- gence light is born.
The Standard Model of the origin of the Universe dominates the modern science of cosmology and at last, through the writings of Hawking and others, is beginning to play an appropriate role in the profounder ruminations of our wider culture. The
Model consumes critical super- latives with the appetite with which a collapsing supernova burns hydrogen. Its speculations are so vast that their signifi- cance can hardly be grasped even by those who can hold in their minds the elegant mathematics on which it rests. It is impossi- ble to predict the effects that its digestion, or indigestion, by the liberally educated mind is likely to have. Its prestige reposes not merely on the awesome elevation or its primordial theme but also on the extent to which it is a product not of the irresistible pattern of an overwhelming body of evidence but of the abstract deductive capacities of the human mathematical imagination as beautifully captured by Einstein's remark that, were his predictions to be falsified by experiment, he would be
sorry for God, since the calculations were correct. The worldview of 20th-century physics emerged from the womb of pure thought into the midwifely hands of experi- mental science.
Experiment has sat on the shoulder of theory, but without its guidance theory wanders in the dark. It is the conceptual boldness of the theoreticians that has fasci- nated, so far, the educated public, but it is experiment that entitles us to the Faustian sense of reaching out to reality. And the art of experimental confirmation poses extraordinary problems of its own to be overcome only by a combination of ingenuity, determination and fantasy. There could be no better illustration than the establishment, narrated in Wrinkles in Time, of one of the central requirements of the Standard Model. The suggestion that radiation separated from matter after 300,000 years was spectacularly confirmed by the accidental discovery of the so-called Cosmic Background Radiation in the 1960s. This strongly implied that there had indeed once been a massive energy release uniformly across the entire cosmos. The uniformity was very great, pointing indis- putably to a cosmogonical origin, but the complete absence of any unevenness posed a severe theoretical problem. For the even- ness of the energy at the point of decoupling must have been matched by that of the distribution of matter, but, if matter were really spread at its emergence so uniformly across the world, then entropy, the principle of the universal eter- nal and irreversible diminution of ordered structure, forbade the evolution of the dis- pensation in which we now live with its density and complexity variations on the order of many powers of ten between the ■ centres or black holes or the contents of the human cranium and the depths of the vast voids between galactic superciusters.
The credibility of the entire Standard Model was threatened by the anisotropy, the utter lack of any contour of the Back- ground Radiation. It could be saved only by still more meticulous scrutiny of the evi- dence. But the Background Radiation is extraordinarily faint and the circumambi- ent sources of disturbance are cacophonously intense. To detect the one against the other required exquisite experi- mental skill. Many were deterred by the seeming impossibility of the task, but oth- ers were attracted by the paramount signif- icance of the issue and for the last 20 years the race to find anisotropy has been on. This book tells the winner's story.
To have any hope of suitably inspecting the Background Radiation it is imperative to escape from the radio pollution of the earth's immediate atmosphere, and Smoot turned in succession to balloons, spy planes and satellites to achieve the stratospheric calm that his instruments required. He describes in detail the splendours and mis- eries of entrusting enormously elaborate machinery, the irreplaceable fruit of years of patient problem-solving, to the whimsi- cal ascent of a canvasful of helium, the des- perate gerrymandering of military technology or the ignition of 100 feet of high explosives. Nor of course were techni- cal difficulties the only ones to be over- come. Smoot is compelling in his description of the practical obstacles posed by the bureaucratic administration of sci- ence and the constraints of the public econ- omy. His case is an illustration of the fact that the completion of research pro- grammes in science is not, as has often been claimed, merely a function of the degree of political lobbying that the researchers can mobilise. It can sometimes be the effect of almost Wagnerian displays of determination by obsessed individuals.
Smoot's reward came when, in April last year, he stunned the world with the pro- duction not merely of proof of the anisotropies of the Background Radiation but with a relief map of their arrangement. His feelings at this point are engagingly described, one's admiration and sympathy considerable. Wrinkles in Time, then, is the account of an experimental adventure. The theatrical background is sketched, but for a survey of the state of current cosmophysics one is much better advised to turn to Steven Weinberg's masterly Dreams of a Final Theory. On the other hand, anyone fascinated but bemused by the esoteric ramifications of the theory will find this consistently readable account of the hand- dirtying business of experiment a salutary tonic. The book is not entirely without its stylistic naiveties, perhaps, and the tempta- tion to include the word 'Time' in the title might have been repressed, but the exhila- ration of solving a 20-year crossword puzzle is most effectively conveyed.
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