This classic text, aimed at senior undergraduates and beginning graduate students in physics and astronomy, presents a wide range of astrophysical concepts in sufficient depth to give the reader a quantitative understanding of the subject. Emphasizing physical concepts, the book outlines cosmic events, but does not portray them in detail - it provides a series of astrophysical sketches. For this third edition, nearly every part of the text has been reconsidered and rewritten; new sections have been added to cover recent developments, and most of the rest has been revised and brought up to date. The book begins with an outline of the scope of modern astrophysics and the elementary problems concerning the scale of cosmic objects and events. The basic physics needed to answer these questions is developed in the next chapters, using specific astronomical processes as examples. The second half of the book enlarges on the topics introduced at the beginning and shows how we can obtain quantitative insights into the structure and evolution of stars, the dynamics of cosmic gases, the large-scale behavior of the universe, and the origins of life. supernovae, comets, quasars) are mentioned throughout the text whenever the relevant physics is discussed rather than in individual sections. To compensate, there is an appendix that gives a brief background of astronomical concepts for students unfamiliar with astronomical terminology, as well as a comprehensive index. The extensive bibliography refers to other sources that treat individual topics in detail.

Martin Harwit, author of the influential book Cosmic Discovery, asks key questions about the scope of observational astronomy. Humans have long sought to understand the world we inhabit. Recent realization of how our unruly Universe distorts information before it ever reaches us reveals distinct limits on how well we will ultimately understand the Cosmos. Even the best instruments we might conceive will inevitably be thwarted by ever more complex distortions and will never untangle the data completely. Observational astronomy, and the cost of pursuing it, will then have reached an inherent end. Only some totally different lines of approach, as yet unknown and potentially far more costly, might then need to emerge if we wish to learn more. This accessible book is written for all astronomers, astrophysicists, and those curious about how well we will ever understand the Universe and the potential costs of pushing those limits.

Astrophysicist and scholar Martin Harwit examines how our understanding of the cosmos advanced rapidly during the twentieth century and identifies the factors contributing to this progress. Astronomy, whose tools were largely imported from physics and engineering, benefited mid-century from the US policy of coupling basic research with practical national priorities. This strategy, initially developed for military and industrial purposes, provided astronomy with powerful tools yielding access - at virtually no cost - to radio, infrared, X-ray, and gamma-ray observations. Today, astronomers are investigating the new frontiers of dark matter and dark energy, critical to understanding the cosmos but of indeterminate socio-economic promise. Harwit addresses these current challenges in view of competing national priorities and proposes alternative new approaches in search of the true Universe. This is an engaging read for astrophysicists, policy makers, historians, and sociologists of science looking to learn and apply lessons from the past in gaining deeper cosmological insight.

At 8:15 A.M., August 6, 1945, the Enola Gay released her load. For forty three seconds, the world's first atomic bomb plunged through six miles of clear air to its preset detonation altitude. There it exploded, destroying Hiroshima and eighty thousand of her citizens. No war had ever seen such instant devastation. Within nine days Japan surrendered. World War II was over and a nuclear arms race had begun. Fifty years later, the National Air and Space Museum was in the final stages of preparing an exhibition on the Enola Gay's historic mission when eighty-one members of Congress angrily demanded cancellation of the planned display and the resignation or dismissal of the museum's director. The Smithsonian tnstitution, of which the National Air and Space Museum is a part, is heavily dependent on congressional funding. The Institution's chief executive, Smithsonian Secretary I. Michael Heyman, in office only four months at the time, scrapped the exhibit as requested, and promised to personally oversee a new display devoid of any historic context. In the wake of that decision I resigned as the museum's director and left the Smithsonian."

Now in its 4th edition, this classic text presents a quantitative understanding of a range of astrophysical concepts. Emphasizing physical concepts, the book outlines cosmic events but does not portray them in detail. Instead, it provides a series of astrophysical sketches showing how to obtain quantitative insights into the structure and evolution of stars, the dynamics of cosmic gases, the large-scale behavior of the universe, and the origins of life. Nearly every part of the text has been reconsidered and rewritten for the new edition; new sections cover recent developments, and the remainder has been revised and brought up to date.

Martin Harwit's influential book, Cosmic Discovery, is rereleased after more than thirty-five years, with a new preface written by the author. The work chronicles the astronomical discoveries up to the late twentieth century and draws conclusions that major discoveries have often been unexpected, unrelated to prevailing astronomical theories and made by outsiders from other fields. One trend alone seems to prevail: major discoveries follow major technological innovations in observational instruments. The author also examines discovery in terms of its political, financial, and sociological contexts, including the role of industry and the military in enabling new technologies, and methods of funding. The challenges encountered by astronomy in the 1980s are remarkably similar to those astronomers face today. Difficulties persist in controlling recurrent cost overruns on planned missions, and in confronting mounting costs in developing observatories for detecting gravitational waves, high-energy cosmic rays, and particles that might explain dark matter.