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Applications of early astronomical records
Physics of the Earth and Planetary Interiors, 21(1980) 71—74 © Elsevier Scientific Publishing Company, Amsterdam — Printed in The Netherlands
71
BOOK REVIEWS Applications ofEarly AstronomicalRecords. F.R. Stephenson and D.H. Clark. Adam Hilger Ltd., Bristol, 1978, X + 114 pp., ISBN 0-85274-342-4, £9.50.
Due to the restriction in the length of present-day titles of books, the reviewer will find in most cases an additional more precise but longer description of the content. Here, the following could be suggested: “Early records of astronomical interest and their evaluation”. The book does not cover those applications in which astronomy serves as an auxiliary science for other purposes (e.g. dating of historical events). Within their general framework, the authors concentrate on three topics: (a) solar eclipses and the rotation of the Earth, (b) “new stars”, especially supernovae, and (c) indicators of solar activity, Only records in the sense of man-made records are dealt with explicitly. There is a slight departure from this rule in a less important case (14C as an indicator of solar activity), while the more important palaeontological evidence for the rotation of the Earth is not treated. We may hope that this kind of evidence will provide the topic for another monograph. Before entering discussion of the three themes mentioned above, the historical sources are reviewed. They all stem from the Old World, which is reasonable, since in the New World the order of priority is reversed: astronomy serves to elucidate history rather than vice-versa. It is refreshing that this introduction does give notwithstanding its brevity many examples of different types of observations. In this way the reader obtains immediate insight into the nature of the sources, allowing, of course, for the inevitable difficulties encountered in providing an “ideal” translation of the ancient texts. In the introduction one also finds examples of the one important subject not covered under the above three areas: objects of the planetary system other than the Earth, Sun and Moon. While configurations of planets might —
—
occasionally have had an immediate scientific value, the observations of comets and meteors with all their transient phenomena must also be regarded as important. With regard to the completeness of our historical knowledge, it is possible that further research might lead to the detection of important events after the end of the compilations of mediaeval chronicles (about AD 1250). The first group of observations of which the applications are described are those of the solar eclipses. They are an especially appropriate example for demonstrating the qualitatively different kinds of value to be attributed to such records. In assessing the value of an individual report, the following particular points are made: (a) the clarity of the report with regard to the totality of the eclipse is basic; (b) the quality of the information on time and longitude increases with the distance from the section of the totality path parallel to latitude circles on the Earth; (c) the remaining observations have to be treated with a consideration of such effects as, for example, “population bias”. Certainly, a large element of personal judgement enters also, as one can learn from the comparison of lists of “reliable” eclipses selected by Dr. Stephenson (the one eclipse from Novgorod has been exchanged, etc.). While the historical information concerning eclipses may be seen as an ensemble of data which is made valuable only through a simultaneous and homogeneous treatment, the situation is completely different for the second group of observations, that of “new stars”. Each mdividual case if definitely ascertained has its own value, and the main question is that of the correct interpretation of specific cases. The reader is most likely aware of the famous three galactic supernovae associated with historical events. It is less well known that historical studies, combined with present astrophysical searches for supernova remnants, have produced evidence for one more certain case and four more probable cases. With regard to Cas A and any remnants, where the motion of remnant filaments —
—
72
might be measured, the reviewer would draw attention to analogous measurements of the filament motions of the Crab nebula, which suggest a younger age than that indicated by the historical reports; therefore, decisions on the identification of historical reports with Cas A should not be based on the demand for an agreement between those dates. The last section is devoted to the recently renewed interest in historical indicators of solar activity. The main source of information in the period under consideration is provided by naked-eye observations of sunspots. The only quantity which can in practice be derived from this source is the number of such observations made within a given period of time. Due to the statistical nature of this quantity, the very many non-scientific reasons for the accumulation (or repression!) of sunspot sightings will influence our interpretation even more than in the fields mentioned before. The Arts and the Sciences have to cooperate in the utilization of the historical heritage. This book is one of the still rare examples of such a cooperation, and it is a commendable one. We may close with the last sentence of the preface: “In no science other than astronomy are the written records of the past so directly relevant to current research”. P. BROSCHE (Bonn)
The Encyclopaedia of Ignorance. Ronald Duncan and Miranda Weston-Smith (Editors). Pergamon Press, Oxford, 443 pp., ISBN 0-08 022426-1, £ 7.50 (flexicover).
We cannot know what we do not know. We can of course ask questions the answers to which are unknown. Some questions are unanswerable and belong to metaphysics and philosophy, where posing questions is an end in itself. This book is directed to some presently unanswered questions in the realm of science, the answers to many of which will doubtless emerge in the fullness of time. In a general way it is a rather disappointing exercise, as such questions are often concerned with the details of some existing theoretical model or paradigm. The questions tend to be aimed at picking holes, or crossing the “t’s” and
dotting the “i’s”, in such areas as evolutionary theory, quantum mechanics, or even plate tectonics. Nevertheless, the present collection of 50 articles by eminent scientists, Nobel laureates and so on makes stimulating reading. The first half of the book is concerned with the physical scierices and mathematics. As might be expected, the physical sciences section is largely concerned with subjects involving long distances in space or large intervals in time, or which are otherwise inaccessible cosmogony and cosmology, the evolution and structure of stars, the origin of the solar system. Philosophical matters, such as the nature of physical theories and scientists’ attitudes towards them, the purpose of physical processes, the existence of hidden variables behind the probablistic description of events and the asymmetry of time, are discussed. A number of articles deal with the geometry and connectivity of space, gravitation, the questions of the relationship between the microscopic and macroscopic worlds, or whether an observable has a value until it is measured. Heady stuff, but fortunately most contributions are quite short and the reader can rest between the highly stimulating intellectual doses. In many cases I would suspect that the contributions are at a too highly specialized level to be readily understood by the informed layman whom the editors had in mind in preparing the book. The second half of the book contains two articles on the Earth sciences. The questions asked by Preston Cloud in a short contribution concern the evolution and outgassing of the Earth’s crust,the nature of life during the first four thousand million years of the Earth’s history, the existence of folded and thrustfaulted mountains within plates, and the mechanism which makes “hot spots” come and go. The second article by N.L. Falcon is a plea for more boreholes by which many geological and geophysical problems would be resolved. The contributions on the life sciences include a number of comprehensible and fascinating articles on the theory of evolution, the origin of Man, the purpose of sleep, of pain, the nature of memory, symmetry and assymmetry in animals all essential reading for the would-be polymath! —
—
W. O’REILLY (Newcastle upon Tyne)
71
BOOK REVIEWS Applications ofEarly AstronomicalRecords. F.R. Stephenson and D.H. Clark. Adam Hilger Ltd., Bristol, 1978, X + 114 pp., ISBN 0-85274-342-4, £9.50.
Due to the restriction in the length of present-day titles of books, the reviewer will find in most cases an additional more precise but longer description of the content. Here, the following could be suggested: “Early records of astronomical interest and their evaluation”. The book does not cover those applications in which astronomy serves as an auxiliary science for other purposes (e.g. dating of historical events). Within their general framework, the authors concentrate on three topics: (a) solar eclipses and the rotation of the Earth, (b) “new stars”, especially supernovae, and (c) indicators of solar activity, Only records in the sense of man-made records are dealt with explicitly. There is a slight departure from this rule in a less important case (14C as an indicator of solar activity), while the more important palaeontological evidence for the rotation of the Earth is not treated. We may hope that this kind of evidence will provide the topic for another monograph. Before entering discussion of the three themes mentioned above, the historical sources are reviewed. They all stem from the Old World, which is reasonable, since in the New World the order of priority is reversed: astronomy serves to elucidate history rather than vice-versa. It is refreshing that this introduction does give notwithstanding its brevity many examples of different types of observations. In this way the reader obtains immediate insight into the nature of the sources, allowing, of course, for the inevitable difficulties encountered in providing an “ideal” translation of the ancient texts. In the introduction one also finds examples of the one important subject not covered under the above three areas: objects of the planetary system other than the Earth, Sun and Moon. While configurations of planets might —
—
occasionally have had an immediate scientific value, the observations of comets and meteors with all their transient phenomena must also be regarded as important. With regard to the completeness of our historical knowledge, it is possible that further research might lead to the detection of important events after the end of the compilations of mediaeval chronicles (about AD 1250). The first group of observations of which the applications are described are those of the solar eclipses. They are an especially appropriate example for demonstrating the qualitatively different kinds of value to be attributed to such records. In assessing the value of an individual report, the following particular points are made: (a) the clarity of the report with regard to the totality of the eclipse is basic; (b) the quality of the information on time and longitude increases with the distance from the section of the totality path parallel to latitude circles on the Earth; (c) the remaining observations have to be treated with a consideration of such effects as, for example, “population bias”. Certainly, a large element of personal judgement enters also, as one can learn from the comparison of lists of “reliable” eclipses selected by Dr. Stephenson (the one eclipse from Novgorod has been exchanged, etc.). While the historical information concerning eclipses may be seen as an ensemble of data which is made valuable only through a simultaneous and homogeneous treatment, the situation is completely different for the second group of observations, that of “new stars”. Each mdividual case if definitely ascertained has its own value, and the main question is that of the correct interpretation of specific cases. The reader is most likely aware of the famous three galactic supernovae associated with historical events. It is less well known that historical studies, combined with present astrophysical searches for supernova remnants, have produced evidence for one more certain case and four more probable cases. With regard to Cas A and any remnants, where the motion of remnant filaments —
—
72
might be measured, the reviewer would draw attention to analogous measurements of the filament motions of the Crab nebula, which suggest a younger age than that indicated by the historical reports; therefore, decisions on the identification of historical reports with Cas A should not be based on the demand for an agreement between those dates. The last section is devoted to the recently renewed interest in historical indicators of solar activity. The main source of information in the period under consideration is provided by naked-eye observations of sunspots. The only quantity which can in practice be derived from this source is the number of such observations made within a given period of time. Due to the statistical nature of this quantity, the very many non-scientific reasons for the accumulation (or repression!) of sunspot sightings will influence our interpretation even more than in the fields mentioned before. The Arts and the Sciences have to cooperate in the utilization of the historical heritage. This book is one of the still rare examples of such a cooperation, and it is a commendable one. We may close with the last sentence of the preface: “In no science other than astronomy are the written records of the past so directly relevant to current research”. P. BROSCHE (Bonn)
The Encyclopaedia of Ignorance. Ronald Duncan and Miranda Weston-Smith (Editors). Pergamon Press, Oxford, 443 pp., ISBN 0-08 022426-1, £ 7.50 (flexicover).
We cannot know what we do not know. We can of course ask questions the answers to which are unknown. Some questions are unanswerable and belong to metaphysics and philosophy, where posing questions is an end in itself. This book is directed to some presently unanswered questions in the realm of science, the answers to many of which will doubtless emerge in the fullness of time. In a general way it is a rather disappointing exercise, as such questions are often concerned with the details of some existing theoretical model or paradigm. The questions tend to be aimed at picking holes, or crossing the “t’s” and
dotting the “i’s”, in such areas as evolutionary theory, quantum mechanics, or even plate tectonics. Nevertheless, the present collection of 50 articles by eminent scientists, Nobel laureates and so on makes stimulating reading. The first half of the book is concerned with the physical scierices and mathematics. As might be expected, the physical sciences section is largely concerned with subjects involving long distances in space or large intervals in time, or which are otherwise inaccessible cosmogony and cosmology, the evolution and structure of stars, the origin of the solar system. Philosophical matters, such as the nature of physical theories and scientists’ attitudes towards them, the purpose of physical processes, the existence of hidden variables behind the probablistic description of events and the asymmetry of time, are discussed. A number of articles deal with the geometry and connectivity of space, gravitation, the questions of the relationship between the microscopic and macroscopic worlds, or whether an observable has a value until it is measured. Heady stuff, but fortunately most contributions are quite short and the reader can rest between the highly stimulating intellectual doses. In many cases I would suspect that the contributions are at a too highly specialized level to be readily understood by the informed layman whom the editors had in mind in preparing the book. The second half of the book contains two articles on the Earth sciences. The questions asked by Preston Cloud in a short contribution concern the evolution and outgassing of the Earth’s crust,the nature of life during the first four thousand million years of the Earth’s history, the existence of folded and thrustfaulted mountains within plates, and the mechanism which makes “hot spots” come and go. The second article by N.L. Falcon is a plea for more boreholes by which many geological and geophysical problems would be resolved. The contributions on the life sciences include a number of comprehensible and fascinating articles on the theory of evolution, the origin of Man, the purpose of sleep, of pain, the nature of memory, symmetry and assymmetry in animals all essential reading for the would-be polymath! —
—
W. O’REILLY (Newcastle upon Tyne)