Shapes And Dynamics Of Granular Minor Planets

This book develops a general approach that can be systematically refined to investigate the statics and dynamics of deformable solid bodies. These methods are then employed to small bodies in the Solar System. With several space missions underway and more being planned, interest in our immediate neighbourhood is growing. In this spirit, this book investigates various phenomena encountered in planetary science, including disruptions during planetary fly-bys, equilibrium shapes and stability of small rubble bodies, and spin-driven shape changes. The flexible procedure proposed here will help readers gain valuable insights into the mechanics of solar system bodies, while at the same time complementing numerical investigations. The technique itself is built upon the virial method successfully employed by Chandrasekhar (1969) to study the equilibrium shapes of spinning fluid objects. However, here Chandrasekhar’s approach is modified in order to study more complex dynamical situations and include objects of different rheologies, e.g., granular aggregates, or “rubble piles”. The book is largely self-contained, though some basic familiarity with continuum mechanics will be beneficial.

"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.

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.

This book focuses on the impact dynamics and cratering of soft matter to describe its importance, difficulty, and wide applicability to planetary-related problems. A comprehensive introduction to the dimensional analysis and constitutive laws that are necessary to discuss impact mechanics and cratering is first provided. Then, particular coverage is given to the impact of granular matter, which is one of the most crucial constituents for geophysics. While granular matter shows both solid-like and fluid-like behaviors, neither solid nor fluid dynamics is sufficient to fully understand the physics of granular matter. In order to reveal its fundamental properties, extensive impact tests have been carried out recently. The author reveals the findings of these recent studies as well as what remains unsolved in terms of impact dynamics. Impact crater morphology with various soft matter impacts also is discussed intensively. Various experimental and observational results up to the recent Itokawa asteroid’s terrain and nanocrater are reviewed and explained mainly by dimensional analysis. The author discusses perspectives of the relation between soft matter physics and planetary science, because it is an important step towards unifying physics and planetary science, in both of which fields crater morphology has been studied independently.

The small bodies in planetary systems are indicative of the material evo- tion, the dynamical evolution, and the presence of planets in a system. Recent astronomicalresearch,spaceresearch,laboratoryresearch,andnumericals- ulationsbroughtawealthofnewandexciting?ndingsonextra-solarplanetary systems and on asteroids, comets, meteoroids, dust, and trans-Neptunian - jects in the solar system. Progress in astronomical instrumentation led to the discovery and investigation of small bodies in the outer solar system and to observations of cosmic dust in debris disks of extra-solar planetary systems. Space research allowed for close studies of some of the small solar system bodies from spacecraft. This lecture series is intended as an introduction to the latest research results and to the key issues of future research. The ch- ters are mainly based on lectures given during a recent research school and on research activities within the 21st Century COE Program “Origin and Evolution of Planetary Systems” at Kobe University, Japan. In Chap. 1, Taku Takeuchi discusses the evolution of gas and dust from protoplanetary disks to planetary disks. Using a simple model, he studies v- cous evolution and photoevaporation as possible mechanisms of gas dispersal. He further considers how the dust grows into planetesimals. Motion of dust particles induced by gas drag is described, and then using a simple analytic model, the dust growth timescale is discussed.

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.

This book is a thorough and engaging presentation of the key concepts in planetary ring science informed by the latest research findings.