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.
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.
Proceedings of the Fourth International Conference on Large Meteorite Impacts and Planetary Evolution held at the Vredefort Dome, South Africa, in Aug. 2008.
As end-of-the-world scenarios go, an apocalyptic collision with an asteroid or comet is the new kid on the block, gaining respectability only in the last decade of the 20th century with the realisation that the dinosaurs had been wiped out by just such an impact. Now the science community is making up for lost time, with worldwide efforts to track the thousands of potentially hazardous near-Earth objects, and plans for high-tech hardware that could deflect an incoming object from a collision course – a procedure depicted, with little regard for scientific accuracy, in several Hollywood movies. Astrophysicist and science writer Andrew May disentangles fact from fiction in this fast-moving and entertaining account, covering the nature and history of comets and asteroids, the reason why some orbits are more hazardous than others, the devastating local and global effects that an impact event would produce, and – more optimistically – the way future space missions could avert a catastrophe.
'Astonishing' - New Scientist Icy, rocky, sometimes dusty, always mysterious – comets and asteroids are among the Solar System's very oldest inhabitants, formed within a swirling cloud of gas and dust in the area of space that eventually hosted the Sun and its planets. Locked within each of these extra-terrestrial objects is the 4.6-billion-year wisdom of Solar System events, and by studying them at close quarters using spacecraft we can coerce them into revealing their closely-guarded secrets. This offers us the chance to answer some fundamental questions about our planet and its inhabitants. Exploring comets and asteroids also allows us to shape the story of Earth's future, enabling us to protect our precious planet from the threat of a catastrophic impact from space, and maybe to even recover valuable raw materials from them. This cosmic bounty could be as useful in space as it is on Earth, providing the necessary fuel and supplies for humans as they voyage into deep space to explore more distant locations within the Solar System. Catching Stardust tells the story of these enigmatic celestial objects, revealing how scientists are using them to help understand a crucial time in our history – the birth of the Solar System, and everything contained within it.
New Natures broadens the dialogue between the disciplines of science and technology studies (STS) and environmental history in hopes of deepening and even transforming understandings of human-nature interactions. The volume presents richly developed historical studies that explicitly engage with key STS theories, offering models for how these theories can help crystallize central lessons from empirical histories, facilitate comparative analysis, and provide a language for complicated historical phenomena. Overall, the collection exemplifies the fruitfulness of cross-disciplinary thinking. The chapters follow three central themes: ways of knowing, or how knowledge is produced and how this mediates our understanding of the environment; constructions of environmental expertise, showing how expertise is evaluated according to categories, categorization, hierarchies, and the power afforded to expertise; and lastly, an analysis of networks, mobilities, and boundaries, demonstrating how knowledge is both diffused and constrained and what this means for humans and the environment. Contributors explore these themes by discussing a wide array of topics, including farming, forestry, indigenous land management, ecological science, pollution, trade, energy, and outer space, among others. The epilogue, by the eminent environmental historian Sverker Sorlin, views the deep entanglements of humans and nature in contemporary urbanity and argues we should preserve this relationship in the future. Additionally, the volume looks to extend the valuable conversation between STS and environmental history to wider communities that include policy makers and other stakeholders, as many of the issues raised can inform future courses of action.
Impact cratering is arguably the most ubiquitous geological process in the Solar System. It has played an important role in Earth’s history, shaping the geological landscape, affecting the evolution of life, and generating economic resources. However, it was only in the latter half of the 20th century that the importance of impact cratering as a geological process was recognized and only during the past couple of decades that the study of meteorite impact structures has moved into the mainstream. This book seeks to fill a critical gap in the literature by providing an overview text covering broad aspects of the impact cratering process and aimed at graduate students, professionals and researchers alike. It introduces readers to the threat and nature of impactors, the impact cratering process, the products, and the effects – both destructive and beneficial. A series of chapters on the various techniques used to study impact craters provide a foundation for anyone studying impact craters for the first time.
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.
In 1908, thunderous blasts and blazing fires from the sky descended upon the desolate Tunguska territory of Siberia. The explosion knocked down an area of forest larger than London and was powerful enough to obliterate Manhattan. The mysterious nature of the event has prompted a wide array of speculation and investigation, including from those who suspected that aliens from outer space had been involved. In this deeply researched account of the Tunguska explosion and its legacy in Russian society, culture, and the environment, Andy Bruno recounts the intriguing history of the disaster and researchers' attempts to understand it. Taking readers inside the numerous expeditions and investigations that have long occupied scientists, he foregrounds the significance of mystery in environmental history. His engaging and accessible account shows how the explosion has shaped the treatment of the landscape, how uncertainty allowed unusual ideas to enter scientific conversations, and how cosmic disasters have influenced the past and might affect the future.
