Titlebook: Comets and the Origin and Evolution of Life; Paul J. Thomas,Christopher F. Chyba,Christopher P. Book 19971st edition Springer Science+Busi

生来

漂白

Comets and the Origin and Evolution of Life,The historical development of the study of comets and the origins of life is reviewed.

GULF

The Origin of the Atmosphere and of the Oceans,The atmosphere of the Earth, its oceans as well as most carbon contained in its carbonates and in organic matter, seem to have been brought by a large bombardment of comets that lasted almost one billion years before diminishing drastically to its present-day value.

言行自由

Absenteeism

Introduction: Comets and the Origin of Life,iosphere: they were both deliverers of organic material and volatiles, and also destroyers of organic material, by the heat and shock of violent impact. The study of the origins of life on Earth attempts to uncover the physical processes operating during this earliest, very turbulent era in the hist

技术

Bereavement

micturition

疏忽

Comets as a Source of Prebiotic Organic Molecules for the Early Earth,em, was subjected to an intense bombardment of comets and asteroids. This bombardment may have rendered the Earth’s surface inhospitable for life for hundreds of millions of years subsequent to terrestrial formation. It may also have delivered to the Earth’s surface the bulk of the current terrestri

formula

Cometary Impacts on the Biosphere,idence includes impact craters formed close to boundary events, iridium and other siderophile element/isotope anomalies, microtektites, and shocked quartz. Mass extinctions, crater excavations, and various geologic upheavals all seem to follow a common periodicity of ~30 Myr. Another cycle of ~250 M