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Preface to the First Edition
Preface t o the First Edition
The innermost regions of the Earth are inaccessible to man and no direct measurements of any of its physical properties can be made. Much attention has been given in the last few years to the “inverse problem in geophysicsthat of determining some physical parameter from a set of observations made at the surface of the Earth. Our knowledge of the core of the Earth comes from many different fields, of which seismology and geomagnetism are the most important and a discussion of these disciplines form a large part of this book. The role of the Earth’s core is essential to our understanding of many geophysical phenomena-it is the seat of the Earth’s magnetic field and coupling between the core and mantle is responsible for some of the variations in the length of the day. The advent of satellites and spacecraft to the moon and terrestrial planets has given an added interest to the internal properties of these bodies-measurements of their magnetic field has already given us some clues on their constitution and possible cores. The question of cores in the other planets is discussed in the last chapter. J. A. JACOBS J u l y 1975 ”
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The innermost regions of the Earth are inaccessible to man and no direct measurements of any of its physical properties can be made. Much attention has been given in the last few years to the “inverse problem in geophysicsthat of determining some physical parameter from a set of observations made at the surface of the Earth. Our knowledge of the core of the Earth comes from many different fields, of which seismology and geomagnetism are the most important and a discussion of these disciplines form a large part of this book. The role of the Earth’s core is essential to our understanding of many geophysical phenomena-it is the seat of the Earth’s magnetic field and coupling between the core and mantle is responsible for some of the variations in the length of the day. The advent of satellites and spacecraft to the moon and terrestrial planets has given an added interest to the internal properties of these bodies-measurements of their magnetic field has already given us some clues on their constitution and possible cores. The question of cores in the other planets is discussed in the last chapter. J. A. JACOBS J u l y 1975 ”
V