An insider's look at the science of near-Earth comets and asteroids Of all the natural disasters that could befall us, only an Earth impact by a large comet or asteroid has the potential to end civilization in a single blow. Yet these near-Earth objects also offer tantalizing clues to our solar system's origins, and someday could even serve as stepping-stones for space exploration. In this book, Donald Yeomans introduces readers to the science of near-Earth objects—its history, applications, and ongoing quest to find near-Earth objects before they find us. In its course around the sun, the Earth passes through a veritable shooting gallery of millions of nearby comets and asteroids. One such asteroid is thought to have plunged into our planet sixty-five million years ago, triggering a global catastrophe that killed off the dinosaurs. Yeomans provides an up-to-date and accessible guide for understanding the threats posed by near-Earth objects, and also explains how early collisions with them delivered the ingredients that made life on Earth possible. He shows how later impacts spurred evolution, allowing only the most adaptable species to thrive—in fact, we humans may owe our very existence to objects that struck our planet. Yeomans takes readers behind the scenes of today’s efforts to find, track, and study near-Earth objects. He shows how the same comets and asteroids most likely to collide with us could also be mined for precious natural resources like water and oxygen, and used as watering holes and fueling stations for expeditions to Mars and the outermost reaches of our solar system.

The United States spends approximately $4 million each year searching for near-Earth objects (NEOs). The objective is to detect those that may collide with Earth. The majority of this funding supports the operation of several observatories that scan the sky searching for NEOs. This, however, is insufficient in detecting the majority of NEOs that may present a tangible threat to humanity. A significantly smaller amount of funding supports ways to protect the Earth from such a potential collision or "mitigation." In 2005, a Congressional mandate called for NASA to detect 90 percent of NEOs with diameters of 140 meters of greater by 2020. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies identifies the need for detection of objects as small as 30 to 50 meters as these can be highly destructive. The book explores four main types of mitigation including civil defense, "slow push" or "pull" methods, kinetic impactors and nuclear explosions. It also asserts that responding effectively to hazards posed by NEOs requires national and international cooperation. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies is a useful guide for scientists, astronomers, policy makers and engineers.

Scientists classify comets and asteroids that pass within 28 million miles of Earth's orbit as near-Earth objects (NEOs). Asteroids that collide and break into smaller fragments are the source of most NEOs, and the resulting fragments bombard the Earth at the rate of more than 100 tons a day. Although the vast majority of NEOs that enter Earth's atmosphere disintegrate before reaching the surface, those larger than 100 meters (328 feet) may survive the descent and cause destruction in and around their impact sites. Furthermore, even smaller objects that disintegrate before reaching Earth's surface can cause significant damage. This book examines NASA's NEO Program and assesses the Agency's progress toward meeting statutory and other Program goals. Specifically, it reviews NASA's allocation and use of resources and plans for the future of the Program.

Two hundred years after the first asteroid was discovered, asteroids can no longer be considered mere points of light in the sky. Spacecraft missions, advanced Earth-based observation techniques, and state-of-the-art numerical models are continually revealing the detailed shapes, structures, geological properties, and orbital characteristics of these smaller denizens of our solar system. This volume brings together the latest information obtained by spacecraft combined with astronomical observations and theoretical modeling, to present our best current understanding of asteroids and the clues they reveal for the origin an,d evolution of the solar system. This collective knowledge, prepared by a team of more than one hundred international authorities on asteroids, includes new insights into asteroid-meteorite connections, possible relationships with comets, and the hazards posed by asteroids colliding with Earth. The book's contents include reports on surveys based on remote observation and summaries of physical properties; results of in situ exploration; studies of dynamical, collisional, cosmochemical, and weathering evolutionary processes; and discussions of asteroid families and the relationships between asteroids and other solar system bodies. Two previous Space Science Series volumes have established standards for research into asteroids. Asteroids III carries that tradition forward in a book that will stand as the definitive source on its subject for the next decade.

Presents a realistic, workable plan for defusing a potentially lethal threat from a rogue asteroid or comet. The explosion of a large meteor over Chelyabinsk, Siberia, in February 2013 is just the latest reminder that planet Earth is vulnerable to damaging and potentially catastrophic collisions with space debris of various kinds. In this informative and forward-looking book, veteran aerospace writer William E. Burrows explains what we can do in the future to avoid far more serious impacts from "Near-Earth Objects" (NEOs), as they are called in the planetary defense community. The good news is that humanity is now equipped with the advanced technology necessary to devise a long-term strategy to protect the planet. Burrows outlines the following key features of an effective planetary defense strategy- * A powerful space surveillance system capable of spotting a serious threat from space at least a year in advance * A space craft "nudge" that would throw a collision-course asteroid off target long before it poses the threat of imminent impact * A weapons system to be used as a last-ditch method to blast an NEO should all else fail. The author notes the many benefits for world stability and increasing international cooperation resulting from a united worldwide effort to protect the planet. Combining realism with an optimistic can-do attitude, Burrows shows that humanity is capable of overcoming a potentially calamitous situation.

"More than forty chapters detail our current astronomical, compositional, geological, and geophysical knowledge of asteroids, as well as their unique physical processes and interrelationships with comets and meteorites"--Provided by publisher.

It is known that large asteroids and comets can collide with the Earth with severe consequences. Although the chances of a collision in a person's lifetime are small, collisions are a random process and could occur at any time. This book collects the latest thoughts and ideas of scientists concerned with mitigating the threat of hazardous asteroids and comets. It reviews current knowledge of the population of potential colliders, including their numbers, locations, orbits, and how warning times might be improved. The structural properties and composition of their interiors and surfaces are reviewed, and their orbital response to the application of pulses of energy is discussed. Difficulties of operating in space near, or on the surface of, very low mass objects are examined. The book concludes with a discussion of the problems faced in communicating the nature of the impact hazard to the public.

Leading specialists in various disciplines were first invited to a multidisciplinary workshop funded by ICSU on the topic to gain a better appreciation and perspective on the subject of comet/asteroid impacts as viewed by different disciplines. This volume provides a necessary link between various disciplines and comet/asteroid impacts.

Planetary defense from near-Earth objects such as asteroids is a far more nuanced and challenging topic than it might seem. Each day, technology is making it easier to detect asteroid impact threats in advance, but at present, there is still no easy way to design and implement any form of global defense. This book examines how various asteroid deflection methods can change global political affairs. The authors believe that the final policy for potential Earth impacts should be based on practical engineering solutions and innovative architectural structures, while at the same time reflecting the most recent political science contributions in ethical security studies and security cosmopolitanism. Their focus is not limited to effective engineering solutions, but rather extends to how such proposals resonate in possible political structures of the future. Planetary defense cannot be achieved with technology alone; the chapters in this volume highlight the issues that arise when space science and technology intersect with political science. This complex interdisciplinary project not only demands global participation and collaboration, but also proposes the way we can achieve it. The authors explore various concepts of governance and their far-reaching implications for planetary defense and vice versa—how scientific progress in Solar System observations and asteroid collision engineering influence political science and put pressure on the international legal framework. The text is intentionally written for a diverse scholarly and diplomatic audience in a style accessible to non-specialists and practitioners and can be read by those across diverse disciplinary backgrounds.

The United States is currently the only country with an active, government-sponsored effort to detect and track potentially hazardous near-Earth objects (NEOs). Congress has mandated that NASA detect and track 90 percent of NEOs that are 1 kilometer in diameter or larger. These objects represent a great potential hazard to life on Earth and could cause global destruction. NASA is close to accomplishing this goal. Congress has more recently mandated that by 2020 NASA should detect and track 90 percent of NEOs that are 140 meters in diameter or larger, a category of objects that is generally recognized to represent a very significant threat to life on Earth if they strike in or near urban areas. Achieving this goal may require the building of one or more additional observatories, possibly including a space-based observatory. Congress directed NASA to ask the National Research Council to review NASA's near-Earth object programs. This interim report addresses some of the issues associated with the survey and detection of NEOs. The final report will contain findings and recommendations for survey and detection, characterization, and mitigation of near-Earth objects based on an integrated assessment of the problem.