This book is the first thorough and overdue biography of one of the giants of science in the twentieth century, Jan Hendrik Oort. His fundamental contributions had a lasting effect on the development of our insight and a profound influence on the international organization and cooperation in his area of science and on the efforts and contribution of his native country. This book aims at describing Oort's life and works in the context of the development of his branch of science and as a tribute to a great scientist in a broader sense. The astronomer Jan Hendrik Oort from the Netherlands was founder of studies of the structure and dynamics of the Milky Way Galaxy, initiator of radioastronomy and the European Southern Observatory, and an important contributor to many areas of astronomy, from the study of comets to the universe on the largest scales.
The Andromeda Galaxy – Messier’s M31 – has an almost romantic appeal. It is the most distant object and the only extragalactic object that is visible to the unaided human eye. Now known to be about 21⁄2 million light-years away, it appears in the sky to be several times the width of the full Moon under good seeing conditions. The Andromeda Galaxy and the Rise of Modern Astronomy examines the astronomical studies of Andromeda and its importance to our developing knowledge of the universe. The book discusses how M31 was described both by the Ancients, but more importantly, by astronomers from the nineteenth century to the present. While at the start of the twentieth century the universe was thought of as a finite cosmos dominated by the Milky Way, the study of Andromeda galaxy shattered that image, leading ultimately to the conception of an infinite universe of countless galaxies and vast distances. Even today, M31 is a major focal point for new astronomical discoveries, and it also remains one of the most popular (and rewarding) celestial objects for amateur astronomers to observe and study. This book reveals the little-known history of M31 and the scientists who study it. For all who are interested in astronomy, the skies, and perhaps even the origins of the universe, The Andromeda Galaxy and the Rise of Modern Astronomy provides a first-of-its-kind accessible, informative, and highly readable account of how the study and observation of this celestial object has driven the development of astronomy from ancient times to the present.
This book is an outgrowth of the notes made for the semester lectures on 'Problems of Extragalactic Astronomy' given almost annually during two decades at the Ob servatorio Astronomico of the Universidad de Cordoba. Shorter versions were also given at La Plata, Santiago de Chile, Sao Paulo, Rio de Janeiro and Paraiba. E. Scalise made a Portuguese language version of the notes and encouraged me to publish them; although my friend J. Kleczek is to be blamed for the idea of this book. Not every subject on Extragalactic Astronomy has been touched in this book: instead I have followed those which interested me during 25 years of professional practice in this part of the world. I acknowledge helpful suggestions from M. Pastoriza and G. Carranza, the com prehension of Director L. Milone, and the collaboration of the staff of the Observa tory in Cordoba. R. Tschamler's humor and wit made light the task of producing the English version and M. Pizarro's devotedness produced the edited MS. To both of them I am in deep gratitude. "A book is published out of necessity, otherwise the author would spend his entire life polishing the originals" was the answer given by J. L. Borges to an inquisi tive journalist. These words explain why this book is so different from the lecture notes, and also from the book I was hoping for. I thank B. McCormac and the D. Reidel Publ. Co. for my salvation from Borges' inferno.
Although less well known outside the field than Edwin Hubble, Walter Baade was arguably the most influential observational astronomer of the twentieth century. Written by a fellow astronomer deeply familiar with Baade and his work, this is the first biography of this major figure in American astronomy. In it, Donald Osterbrock suggests that Baade's greatest contribution to astrophysics was not, as is often contended, his revision of Hubble's distance and age scales for the universe. Rather, it was his discovery of two distinct stellar populations: old and young stars. This discovery opened wide the previously marginal fields of stellar and galactic evolution--research areas that would be among the most fertile and exciting in all of astrophysics for decades to come. Baade was born, educated, and gained his early research experience in Germany. He came to the United States in 1931 as a staff member of Mount Wilson Observatory, which housed the world's largest telescope. There, he pioneered research on supernovae. With the 100-inch telescope, he studied globular clusters and the structure of the Milky Way, every step leading him closer to the population concept he discovered during the wartime years, when the skies of southern California were briefly darkened. Most Mount Wilson astronomers were working on weapons-development crash programs devoted to bringing Baade's native country to its knees, while he, formally an enemy alien in their midst, was confined to Los Angeles County but had almost unlimited use of the most powerful telescope in the world. After his great discovery, Baade continued his research with the new 200-inch telescope at Palomar. Always respected and well liked, he became even more famous among astronomers as they shifted their research to the fields he had opened. Publicity-shy and seemingly unconcerned with publication, however, Baade's celebrity remained largely within the field. This accomplished biography at last introduces Baade--and his important work--to a wider public, including the newest generation of skywatchers.
This book contains the noted discussions of a conference on the co-ordination of galactic research, which was held in the Netherlands, in June 1953 by the International Astronomical Union. Topics include: 'Overall structure: nuclear region and halo', 'Local structure: distribution of different types of stars in the plane' and 'Proper motions and radial velocities'.
The present book is a translation of the original German edition (published in 1982) with some minor corrections and improvements. The guide to sup plementary and advanced literature given in the Appendix, however, has been brought up to date. This book is addressed primarily to students taking astronomy as a prin cipal or subsidiary subject, and to scientists of related fields, but amateur as tronomers should also be able to profit from it. For most chapters an elementary knowledge of mathematics and physics will be sufficient, however, Chaps. 5 and 6 impose somewhat greater requirements. In addition the reader should already be acquainted with the basic concepts of stellar physics as treated in introduc tory books, including the spectral types, the system of stellar magnitudes and colours, absolute magnitudes and luminosities, the Herlzsprung-Russell dia gram and its interpretation. A modem textbook should use SI units. On the other hand, the use of the cgs system is still the prevailing custom in astrophysics - together with the special units of astronomy: length is quoted in parsecs [pc], mass in solar masses [M0] and time in years [a]. We have therefore compromised and employed both cgs and SI units in this book, whichever was the appropriate choice in each instance. A table for conversion of cgs units into SI units and vice versa is given in the Appendix.