- Email: [email protected]
Solar system radio astronomy
Book Reviews matical information theory and semantic theory. I t is difficult to hold a fair balance between unnecessary jargon and unintelligible rigor when seeking to introduce the reader to topics of extreme generality admixed with mathematical concepts of a sophisticated character. The authors have achieved a very satisfactory compromise between these two extremes and their book should prove helpful to many readers who wish to be apprized of the subject matter without becoming specialists. JOHN FORMBY
Department of Mathematics, College of Advanced Technology, Birmingham, England SOLAR SYSTEMRADIO ASTRONOMY,edited by Jules Aarons. 416 pages, diagrams, illustrations, 7 X 10 in. New York, Plenum Press, 1965. Price, $17.50. Although the sun is the principal subject, a considerable part of this book deals with planetary and lunar radio emissions and radar reflections. It represents the substance of the lectures given in Athens in 1964 at an Advance Study Institute sponsored by NATO. The result is a wealth of information covering a wide range of radio astronomical investigations of tl~e solar system. As frequently happens in a collection of articles from different authors the contributions vary widely in presentation. It was an excellent plan to start with Righini's admirable survey of the properties of the Sun derived from optical observations. The introductory paper on the solar radio emission by Denisse seems too brief, although the reader seeking more detail is referred to a previous survey by Wild, Smerd and Weiss. The next four chapters appear in the contents under the general heading "The Quiet Sun" but they are predominantly concerned with the slowly varying regions of activity. One of these chapters is an account of solar radio eclipse observations. The following three chapters deal with conclusions derived from systematic studies of the slowly varying components, and there is some tendency for overlap here (e.g. the same diagram appears twice, P. 88 and P. 113). The section on radio bursts begins with a short survey of the subject by McLean. Although the article by Warwick on spectral VoL 281, No. 2, February 1966
observations seems too detailed, it does bring home the complexity of the solar radio disturbances, and the importance of combining optical observations with the radio measurements. Further chapters on characteristic types of radio bursts follow. Many readers feeling saturated with the fascinating complexities of solar radio bursts, may welcome the second half of the book where the subject moves out to the solar corona and interplanetary ionization. Radio studies of these plasmas are opening an increasingly fruitful field of research. There are interesting articles by Hewish on the scattering influence of ionization irregularities on the waves from radio sources, and b y Eshleman on methods involving investigations of Doppler frequency and other wave characteristics using transmitters and receivers both on the ground and in space probes. The long chapter by Weaver on thermal emission from the Moon is a very comprehensive article starting from the basic equations of thermal and radio propagation and leading on to the results of research. This is accompanied by a further but shorter paper by PettengiU on lunar reflections. The final chapters on planetary emissions and radar echoes contain many points of interest. Although well up-to-date when they were prepared, two new results can now be mentioned. One is the time differences of the decametre Jupiter bursts received at separated stations giving fresh evidence of the effects of interplanetary ionization, and the second is the influence of Jupiter's satellite Io on the probability of the occurrence of Jupiter bursts. If perhaps one subject seemed lacking, it is a chapter on antenna systems. Information about new radio telescopes for solar radio and radar astronomy would have been a good addition. Many readers would have wished, for instance, to read about Wild's circular array, the Arecibo dish and other new instruments. The book can be recommended as a valuable aid in helping research workers, and others interested in the astronomy of the solar system, to keep abreast with research progress and the current state of knowledge. J. S. HEY
Ministry of Aviation Royal Radar Establishment Worcestershire, England
169
Department of Mathematics, College of Advanced Technology, Birmingham, England SOLAR SYSTEMRADIO ASTRONOMY,edited by Jules Aarons. 416 pages, diagrams, illustrations, 7 X 10 in. New York, Plenum Press, 1965. Price, $17.50. Although the sun is the principal subject, a considerable part of this book deals with planetary and lunar radio emissions and radar reflections. It represents the substance of the lectures given in Athens in 1964 at an Advance Study Institute sponsored by NATO. The result is a wealth of information covering a wide range of radio astronomical investigations of tl~e solar system. As frequently happens in a collection of articles from different authors the contributions vary widely in presentation. It was an excellent plan to start with Righini's admirable survey of the properties of the Sun derived from optical observations. The introductory paper on the solar radio emission by Denisse seems too brief, although the reader seeking more detail is referred to a previous survey by Wild, Smerd and Weiss. The next four chapters appear in the contents under the general heading "The Quiet Sun" but they are predominantly concerned with the slowly varying regions of activity. One of these chapters is an account of solar radio eclipse observations. The following three chapters deal with conclusions derived from systematic studies of the slowly varying components, and there is some tendency for overlap here (e.g. the same diagram appears twice, P. 88 and P. 113). The section on radio bursts begins with a short survey of the subject by McLean. Although the article by Warwick on spectral VoL 281, No. 2, February 1966
observations seems too detailed, it does bring home the complexity of the solar radio disturbances, and the importance of combining optical observations with the radio measurements. Further chapters on characteristic types of radio bursts follow. Many readers feeling saturated with the fascinating complexities of solar radio bursts, may welcome the second half of the book where the subject moves out to the solar corona and interplanetary ionization. Radio studies of these plasmas are opening an increasingly fruitful field of research. There are interesting articles by Hewish on the scattering influence of ionization irregularities on the waves from radio sources, and b y Eshleman on methods involving investigations of Doppler frequency and other wave characteristics using transmitters and receivers both on the ground and in space probes. The long chapter by Weaver on thermal emission from the Moon is a very comprehensive article starting from the basic equations of thermal and radio propagation and leading on to the results of research. This is accompanied by a further but shorter paper by PettengiU on lunar reflections. The final chapters on planetary emissions and radar echoes contain many points of interest. Although well up-to-date when they were prepared, two new results can now be mentioned. One is the time differences of the decametre Jupiter bursts received at separated stations giving fresh evidence of the effects of interplanetary ionization, and the second is the influence of Jupiter's satellite Io on the probability of the occurrence of Jupiter bursts. If perhaps one subject seemed lacking, it is a chapter on antenna systems. Information about new radio telescopes for solar radio and radar astronomy would have been a good addition. Many readers would have wished, for instance, to read about Wild's circular array, the Arecibo dish and other new instruments. The book can be recommended as a valuable aid in helping research workers, and others interested in the astronomy of the solar system, to keep abreast with research progress and the current state of knowledge. J. S. HEY
Ministry of Aviation Royal Radar Establishment Worcestershire, England
169