Of the Utmost Gravity to Didactic Completeness and Recent His Torical Development

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in impressive style with careful attention Of the utmost gravity to didactic completeness and recent his torical development. John D. Barrow Before dwelling on the highnotcs of the individual articles, however, I must first confess I found this volume disappointing 300 Years of Gravitation. Edited by S. W. Hawking and W. Israel. in some respects. Unfortunately, the con Cambridge University Press: 1987. Pp. 684. £45, $69.50. nection with Newton's work is not well explored - nine of the articles manage to IT all began one August day in 1684 when edifice of mathematical physics and avoid any mention of Newton or the Prin Dr Edmond Halley paid a visit to Isaac astronomy rests. Newton's laws of motion cipia, and one author has substituted a Newton's rooms in Cambridge; of that and gravitation, although superseded by brief essay written for another occasion meeting Abraham de Moivre tells us that Einstein's, provide an approximation to beneath a note that his real contribution them that hold good in all the situations was not ready in time. But most striking is After they had been some time together, the we encounter in everyday life. More the narrow scope of the articles commis Dr asked him what he thought the Curve would important than the formulation of these sioned. They are confined, with the excep be that would be described by the Planets sup rules by which Nature moves was the tion of Israel's meticulously researched posing the force of attraction history of white dwarfs, neu towards the Sun to be reciprocal tron stars and black holes, to to the square of their distance current research frontiers in from it. Sr Isaac replied imme general relativity. Where are diately that it would be an Ellip the articles on modern dy sis, the Doctor struck with joy & namics? Celestial mechanics? amazement asked him how he knew it, Why saith he I have The N-body problem? Galac calculated it, Whereupon Dr tic dynamics? The stability of Halley asked him for his calcula the Solar System? The ex tions without any further delay, ploration of the Solar Sys Sr Isaac looked among his papers tem's outer planets and the but could not find it, but he mysterious dynamics of their promised him to renew it, & then ring systems? All of these send it to him. subjects are just as interest ing, just as 'gravitational' and Three months later, true to P------,.,,...... - considerably more relevant his word, Newton sent a to the heritage of the Princi- document to Halley that pia than some subjects that made good his remarkable i~,:~SiJ:::,-,>111 have been included (and, in claim. Encouraged further by 1 the case of the inflationary Halley it took Newton but 14 - --==-=- · -;E=,-=- ---- ...... ,ic. universe, duplicated). And months to transform and ex- '-.o!IIITl"r"l"'M""r-- was there really not enough tend this manuscript into space for a real historical another entitled Philosophiae article on gravitation by a Natura/is Principia Mathe- professional historian? matica. It was destined to Although the book is not become Book I of the Princi- an entirely satisfactory cele- pia. Two further parts fol- l."l!liA~"lt:1-•;a.--~ bration of the Principia and lowed in March and April the last 300 years of gravita- 1687 just two and a half years ~--•••11:::._,_..iii -·~.-.~.-..-:..--- tion, it does provide an out- after Halley's first fortuitous standing survey of the last visit. Weighty matters - the condition of man from A, absolute gravity through decade of gravitation which The first edition of the £, horizontal or good sense and F, wit to I, absolute levity or stark fool. A every astrophysicist should monumental Principia, com- contemporary engraving from the collection at the British Museum. try to read from cover to prised of these three manuscripts, was thoroughly rigorous and 'modern' cover. The only blemish is the publisher's published in London on 5 July 1687 under approach that Newton introduced. The error in not providing an index, an econ the imprimatur of Samuel Pepys, the unity of Nature was displayed by his abil- omy that is made harder to appreciate by President of the Royal Society (whose ity to derive far-reaching and diverse the fact that they have been carried away diary-keeping days were by then far results about the extraterrestrial physical by the centenary implications to such an behind him). A second edition appeared world from a bundle of innocuous-sound- extent that the price of this book is pre in 1713, and the third (and last) in 1726. ingassumptionsthatstemmedfromobser- cisely one hundred times that of the first Three years later the only full English vations of mundane local objects such as edition of the Principia. translation ever made of the original Latin apples and prisms. The articles fall into four groups. The text was completed by Andrew Motte and Despite its vast scope, to most scientists first - Cook on gravitation experiments, published as a two-volume set. the Principia is synonymous with gravity Damour on equations of motion, Will on It is this chain of events that inspired the and with it the first statement of a uni- tests of gravitation theories and Thorne on appearance of this tercentenary volume as versa! law of gravitation. This fact is gravitational waves - covers subject a celebration of the most impressive and reflected in the title and contents of areas with long pedigrees which are firmly comprehensive work of science ever writ- Hawking and Israel's collection of 14 anchored to experiment and observations. ten. Today, no practising scientist reads articles. With only one or two exceptions, Each of these authors is a master at orga the Principia out of necessity but it is the the individual contributions are of the nizing and making sense of a bewildering foundation stone upon which the entire highest quality and expound their subjects array of material, and each has produced a

© 1987 Nature Publishing Group 7_7 _2 ______BOOK REVIEWS------N_A_T_u_R_E_v_o_L_.3_2_9 _29_o_c_T_o_B_ER_19_87 beautiful overview of his subject. charts the thinking and writings of astron In the second group are articles of an omers on 'dark stars' from the eighteenth Skimming through astrophysical nature by Blandford and century to the present, and includes inter Rees. They deal with complicated phe esting accounts of his own thoughts at space nomena that are only partially understood crucial stages in the interpretation of James Trefil and not so well suited to systematic expo mathematical results about black hole sition. Faced with a difficult and wide mechanics and thermodynamics during ranging task, both authors display not the 1960s and early 1970s. Space 2000: Meeting the Challenge of a only the important facts and theories of One of the strongest impressions to be New Era. By Harry L. Shipman. Plenum: high-energy astrophysics and cosmology, gained from these articles is of the divers 1987. Pp.431. $19.95. but also something of the special talents ity of work in modern gravitation physics that are required to work successfully in and the way in whicb gravitation is at last IN this book, University of Delaware these fields where all manner of different ceasing to be the aloof geometrical cousin astronomer Harry Shipman undertakes techniques - mathematical, statistical, of the rest of physics. In astrophysics it nothing less than a survey of space science physical, observational, speculative-are merges with the complexities of high and technology, both past and future, required to produce explanations of energy radiation processes to create spec along with an introduction to the basic phenomena where many different physi tacular physical phenomena. The search science (primarily astronomical) that is cal effects intermingle to confuse us. for gravitational waves exploits the latest being done above the Earth's atmosphere. In the third group are articles of a more technologies to provide astronomers with Despite the book's 400-plus pages, the speculative variety on the frontiers of the promise of a new vista on the Uni sheer volume of the subject matter theory: Penrose describes the paradoxes verse. And in the inner space-time of dictates that the coverage must of neces of quantum reality and the possible role of elementary particles there are the first sity be of the "broad and shallow" as gravity in the collapse of the wave function glimmerings of a convincing theory which opposed to the "deep and narrow" and the determination of the arrow of might conjoin gravity with the other forces variety. Thus, the book is not intended for time; Linde, and Guth and Blau discuss of Nature. those already familiar with the space pro the inflationary universe which the first Who can doubt that Newton would be gramme, but as an introduction for those two authors have done so much to develop pleased but not surprised at these who are not. and promote; Vilenkin manages to tell advances towards a unified description of The book is divided into three sections. you all you need to know about cosmic the physical world and all its forces. For The first concerns the basic physics of strings in a 23-page article that is a model we find that 300 years ago, in the Preface satellite motion, the history of the space of clarity; Schwarz supplies a comprehen to his stupendous book, he could write programme and an analysis of space tech sive yet readable contribution on super that, having determined "the motions of nology. As you might expect from an strings and where he hopes they are going the planets, the comets, the moon and the author who has been deeply involved in ( only time will tell whether they get there sea", he was unfortunately unable to the programme and was, in addition, the via Stockholm); Hawking gives an update determine the remaining structure of the public relations and education officer of of his programme to calculate and interp world from the same propositions because the American Astronomical Society, this ret the wave function of the Universe, and I suspect that they may all depend upon certain part is very well done. Shipman's exten explains his latest thinking about the forces by which the particles of bodies, by some sive experience with the space programme arrow of time and the necessity for the causes hitherto unknown, are either mutually comes through very clearly, and there are weak anthropic principle to be employed impelled towards one another, and cohere in many useful insights. To cite one among in quantum cosmology; and Crnkovic and regular figures, or are repelled and recede from many, he points out a fundamental differ Witten provide a brief and somewhat one another. These forces being unknown, ence between the proposed Space Station philosophers have hitherto attempted the technical exposition on canonical formal search of Nature in vain; but I hope the and the Shuttle - an obvious distinction ism. All the articles in this group deal with principles here laid down will afford some often overlooked by the Station's critics: theoretical subjects that are as yet devoid light either to this or some truer method of the Space Station is modular, which of experimental test or decisive observa philosophy. means that unlike the Shuttle it can tional contact. How right he was. D be built in stages; building it will not, Finally, in the last group are an essay on John D. Barrow is a Lecturer at the Astronomy therefore, necessarily drain money from newtonianism by Weinberg and the fasci Centre, University of Sussex, Brighton BNJ other programmes, as the all-or-nothing nating historical article by Israel. This 9QH, UK. Shuttle programme did in the 1970s. I

Gone but not f orgollen - the dodo head preserved in the Ashmolean Museum, Oxford, as depicted in H. E. Strickland and A.G. Melville's The Dodo and Its Kindred of 1848; the rest ofthe specimen (the right foot apart) was thrown out in 1755, by which time it could not be replaced. The picture is reproduced from Extinct Birds by Errol Fuller, published today in Britain by Viking! Rainbird, price £20. In the United States the book will be published by Facts on File.