Bøger af Hans Rickman

The exploration of our Solar System is rapidly growing in importance as a scientific discipline. During the last decades, great progress has been achieved as the result of space missions to planets and small bodies - as- teroids and comets - and improved remote-sensing methods, as well as due to refined techniques of laboratory measurements and a rapid progress in theoretical studies, involving the development of various astrophysical and geophysical models. These models are based, in particular, on the approach of comparative planetology becoming a powerful tool in revealing evolu- tionary processes which have been shaping the planets since their origin. Comets and asteroids, being identified as remnants of planetary formation, serve as a clue to the reconstruction of Solar System history because they encapsulated the primordial material from which the planets were built up. At the same time, these interplanetary carriers of original matter and mes- sengers from the past, being triggered by dynamical processes well outside our neighboring space, were responsible for numerous catastrophic events when impacting on the planets and thus causing dramatic changes of their natural conditions. In the crossroads of astronomy and geophysics, recent years have seen a growing understanding of the importance of collisional processes through- out the history of the Solar System and, therefore, the necessity to get more insight into the problem of interactions of planets and small bodies.

Planet Earth is part of our Galactic environment, not just the product of it, and it is still today influenced by phenomena related to Galactic forces. Specifically, our planet is affected by its near environment, in particular the small bodies in the Solar System. This book reviews the processes which cause the collisions of these small bodies with the Earth as well as the consequences of such collisions. The various articles take the reader through the Galaxy-Solar System connection to the orbital dynamics of the small bodies and to their number and distribution in near-Earth space. The hazards of the impacts of small bodies on Earth are evaluated, and the geophysical records of such impacts are discussed. The book takes the reader to the forefront of research on both impact cratering and the origin and evolution of small bodies in the Solar System. Thus it brings together two subjects, geophysics and astronomy, which are usually discussed in separate volumes but are closely knit together in this particular area of research.