Free Download of : Asteroids, Comets and Meteorites – Cosmic Invaders of the Earth by Jon Erickson
Asteroids, comets, and meteorites have been objects of fascination,speculation, and fear for most of recorded human history. Early peoples thought that fiery streaks in the sky were omens of ill fortune and sought refuge from their evil powers. Impacts of comets and meteorites
with Earth are now recognized as the main cause for several periods of mass extinction on the planet, including termination of the dinosaurs 66 million years ago. Comets and meteorites may also have brought much of the water, air, and perhaps even life to Earth. The planets themselves coalesced from numerous smaller asteroids, comets, and interplanetary dust.Asteroids, comets, and meteorites were therefore essential for the formation of Earth and life and were also responsible for the end of the line for many species.
In this book, Jon Erickson brilliantly presents the reader with a fascinating and readable treatise on asteroids, comets, and meteorites.The book starts with a discussion on the origin of the solar system, Sun, and planets and then looks at the role of these planetsimals in the formation of Earth. Erickson then examines the importance of impacting meteorite and comets in the heavy bombardment period that marks the first 500 million years of Earth’s history.
This is followed by a survey of different impact craters recognized on other planets in the solar system……..