This book features several of the significant scientific debates and controversies that helped develop space science in the early space era. The debates led to significant new understandings of the constituents and processes occurring beyond Earth’s atmosphere, and often opened new research directions. Scientific speculations with their resultant debates have played an important role in the development and furthering of research in general. The book thus has broad intellectual importance in illustrating how science advances. The book includes debates in the subject areas of heliophysics (physics in the cosmic region that covers particles and magnetic fields flowing from the Sun), Earth’s moon, solar system asteroids and comets, and the origin of cosmic gamma-ray bursts. A final chapter describes two important and surprising early scientific discoveries that involved no debates. The target audience for this book includes (a) active and retired space scientists, (b) space enthusiasts, and (c) students as supplemental (or even prime) reading in an introductory astronomy and/or space science course. The topics of the debates and controversies, their resolutions, and their pointing to further research and understanding of nature are of both historical and contemporary interest, appeal, and value.

"The Value of Space Science provides a rigorous assessment of the value of scientific knowledge and understanding in the context of contemporary space exploration. It argues that traditional spaceflight rationales are deficient, and that the strongest defense of spaceflight comes from its potential to produce intrinsically and instrumentally valuable knowledge and understanding. It engages with contemporary epistemology to articulate an account of the intrinsic value of scientific knowledge and understanding. It also parleys with recent work in science policy and social philosophy of science to characterize the instrumental value of scientific research, identifying space research as an effective generator of new knowledge and understanding. These values found an ethical obligation to engage in scientific examination of the space environment. This obligation has important implications for major space policy discussions, including debates surrounding planetary protection policies, space resource exploitation, and human space settlement. Whereas planetary protection policies are currently employed to prevent biological contamination only of sites of interest in the search for extraterrestrial life, it contends that all sites of interest to space science ought to be protected. Meanwhile, space resource exploitation and human space settlement would result in extensive disruption or destruction of pristine space environments. The overall ethical value of these environments in the production of new knowledge and understanding is greater than their value as commercial or real commodities, and thus, exploitation and settlement of space should be avoided until the scientific community adequately understands these environments"--

Early in 1984, NASA asked the Space Science Board to undertake a study to determine the principal scientific issues that the disciplines of space science would face during the period from about 1995 to 2015. This request was made partly because NASA expected the Space Station to become available at the beginning of this period, and partly because the missions needed to implement research strategies previously developed by the various committees of the board should have been launched or their development under way by that time. A two-year study was called for. To carry out the study the board put together task groups in earth sciences, planetary and lunar exploration, solar and space physics, astronomy and astrophysics, fundamental physics and chemistry (relativistic gravitation and microgravity sciences), and life sciences. Responsibility for the study was vested in a steering group whose members consisted of the task group chairmen plus other senior representatives of the space science disciplines. To the board's good fortune, distinguished scientists from many countries other than the United States participated in this study.

Space Science and Public Engagement: 21st Century Perspectives and Opportunities critically examines the many dimensions of public engagement with space science by exploring case studies that show a spectrum of public engagement formats, ranging from the space science community's efforts to communicate developments to the public, to citizenry attempting to engage with space science issues. It addresses why public engagement is important to space science experts, what approaches they take, how public engagement varies locally, nationally and internationally, and what roles "non-experts" have played in shaping space science. Space scientists, outreach specialists in various scientific disciplines, policymakers and citizens interested in space science will find great insights in this book that will help inform their future engagement strategies. Critically examines how expert organizations and the space science community have sought to bring space science to the public Examines how the public has responded, and in some cases self-organized, to opportunities to contribute to space science Outlines future engagement interests and possibilities

This textbook provides an introduction to gravitational lensing, which has become an invaluable tool in modern astrophysics, with applications that range from finding planets orbiting distant stars to understanding how dark matter and dark energy conspired to form the cosmic structures we see today. Principles of Gravitational Lensing begins with Einstein’s prediction that gravity bends light, and shows how that fundamental idea has spawned a rich field of study over the past century. The gravitational deflection of light was first detected by Eddington during a solar eclipse in May 1919, launching Einstein and his theory of relativity into public view. Yet the possibility of using the phenomenon to unlock mysteries of the Universe seemed remote, given the technology of the day. Theoretical work was carried out sporadically over the next six decades, but only with the discovery of the system Q0957+561 in 1979 was gravitational lensing transformed from a curiosity of general relativity into a practical observational tool. This book describes how the three subfields known as strong lensing, weak lensing, and microlensing have grown independently but become increasingly intertwined. Drawing on their research experience, Congdon and Keeton begin with the basic physics of light bending, then present the mathematical foundations of gravitational lensing, building up to current research topics in a clear and systematic way. Relevant background material from physics and mathematics is included, making the book self-contained. The derivations and explanations are supplemented by exercises designed to help students master the theoretical concepts as well as the methods that drive current research. An extensive bibliography guides those wishing to delve more deeply into particular areas of interest. Principles of Gravitational Lensing is ideal for advanced students and seasoned researchers looking to penetrate this thriving subject and even contribute research of their own.

Space is again in the headlines. E-billionaires Jeff Bezos and Elon Musk are planning to colonize Mars. President Trump wants a "Space Force" to achieve "space dominance" with expensive high-tech weapons. The space and nuclear arms control regimes are threadbare and disintegrating. Would-be asteroid collision diverters, space solar energy collectors, asteroid miners, and space geo-engineers insistently promote their Earth-changing mega-projects. Given our many looming planetary catastrophes (from extreme climate change to runaway artificial superintelligence), looking beyond the earth for solutions might seem like a sound strategy for humanity. And indeed, bolstered by a global network of fervent space advocates-and seemingly rendered plausible, even inevitable, by oceans of science fiction and the wizardly of modern cinema-space beckons as a fully hopeful path for human survival and flourishing, a positive future in increasingly dark times. But despite even basic questions of feasibility, will these many space ventures really have desirable effects, as their advocates insist? In the first book to critically assess the major consequences of space activities from their origins in the 1940s to the present and beyond, Daniel Deudney argues in Dark Skies that the major result of the "Space Age" has been to increase the likelihood of global nuclear war, a fact conveniently obscured by the failure of recognize that nuclear-armed ballistic missiles are inherently space weapons. The most important practical finding of Space Age science, also rarely emphasized, is the discovery that we live on Oasis Earth, tiny and fragile, and teeming with astounding life, but surrounded by an utterly desolate and inhospitable wilderness stretching at least many trillions of miles in all directions. As he stresses, our focus must be on Earth and nowhere else. Looking to the future, Deudney provides compelling reasons why space colonization will produce new threats to human survival and not alleviate the existing ones. That is why, he argues, we should fully relinquish the quest. Mind-bending and profound, Dark Skies challenges virtually all received wisdom about the final frontier.