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.

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.

Comets and asteroids are in some sense the fossils of the solar system. They have avoided most of the drastic physical processing that shaped the planets and thus represent more closely the properties of the primordial solar nebula. What processing has taken place is itself of interest in decoding the history of our solar neighborhood. Near-Earth objects are also of interest because one or more large ones have been blamed for the rare but devastating events that caused mass extinctions of species on our planet, as attested by recent excitement over the impending passage of asteroid 1997 XF11. The comets and asteroids whose orbits bring them close to Earth are clearly the most accessible to detailed investigation, both from the ground and from spacecraft. When nature kindly delivers the occasional asteroid to the surface of Earth as a meteorite, we can scrutinize it closely in the laboratory; a great deal of information about primordial chemical composition and primitive processes has been gleaned from such objects. This report reviews the current state of research on near-Earth objects and considers future directions. Attention is paid to the important interplay between ground-based investigations and spaceborne observation or sample collection and return. This is particularly timely since one U.S. spacecraft is already on its way to rendezvous with a near-Earth object, and two others plus a Japanese mission are being readied for launch. In addition to scientific issues, the report considers technologies that would enable further advances in capability and points out the possibilities for including near-Earth objects in any future expansion of human exploration beyond low Earth orbit.

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.

"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.