Comets

Over forty authorities present sections on the nucleus, dust, coma, and tails of comets, along with sections on their origin, and relationships to other solar system bodies. . . . An excellent book.ÑSpace News "The volume is highly recommended to all interested in comets and the Solar System."ÑJournal of the British Astronomical Association "A good representation of the studies that are currently being done on comets, and it is an extremely good source of information on a wide variety of topics."ÑInternational Comet Quarterly "Extremely well-written and informative. . . . A must for library collections."ÑThe Observatory

What are these graceful visitors to our skies? We now know that they bring both life and death and teach us about our origins. Comet begins with a breathtaking journey through space astride a comet. Pulitzer Prize-winning astronomer Carl Sagan, author of Cosmos and Contact, and writer Ann Druyan explore the origin, nature, and future of comets, and the exotic myths and portents attached to them. The authors show how comets have spurred some of the great discoveries in the history of science and raise intriguing questions about these brilliant visitors from the interstellar dark. Were the fates of the dinosaurs and the origins of humans tied to the wanderings of a comet? Are comets the building blocks from which worlds are formed? Lavishly illustrated with photographs and specially commissioned full-color paintings, Comet is an enthralling adventure, indispensable for anyone who has ever gazed up at the heavens and wondered why. Praise for Comet "Simply the best." —The Times of London "Fascinating, evocative, inspiring." —The Washington Post "Comet humanizes science. A beautiful, interesting book." —United Press International "Masterful . . . science, poetry, and imagination." —The Atlanta Journal & Constitution

Radiating fire and ice, comets as a phenomenon seem part science, part myth. Two thousand years ago when a comet shot across the night sky, it convinced the Romans that Julius Caesar was a god. In 1066, Halley’s Comet was interpreted as a foreshadowing of the death of Harold the Second in the Battle of Hastings. Even today the arrival of a comet often feels auspicious, confirming our hopes, fears, and sense of wonder in the universe. In Comets, P. Andrew Karam takes the reader on a far-ranging exploration of these most beautiful and dramatic objects in the skies, revealing how comets and humanity have been interwoven throughout history. He delves into the science of comets and how it has changed over time; the way comets have been depicted in art, religion, literature, and popular culture; and how comets have appeared in the heavens through the centuries. Comprehensive in scope and beautifully illustrated throughout, the book will appeal not only to the budding astronomer, but to anyone with an appreciation for these compelling and remarkable celestial bodies.

David Levy brings these "ghostly apparitions" to life. With fascinating scenarios both real and imagined, he shows how comets have wreaked their special havoc on Earth and other planets. Beginning with ground zero as comets take form, we track the paths their icy, rocky masses take around our universe and investigate the enormous potential that future comets have to directly affect the way we live on this planet and what we might find as we travel to other planets. In this extraordinary volume, David Levy shines his expert light on a subject that has long captivated our imaginations and fears, and demonstrates the need for our continued and rapt attention.

Since comet Shoemaker-Levy collided with the planet Jupiter with stupendous force in 1994 there has been an upsurge of amateur interest in comets. Most comets are first discovered by amateur astronomers because there are so many amateurs looking for them, and techniques and instruments have improved dramatically in the past few years. After a short but detailed introduction to the comets themselves Nick James and Gerald North describe comet hunting, photographing and imaging comets, and digital image processing. The use of computers for orbital calculations and even helping to discover new comets is given a full chapter, as are advanced techniques including comet photometry and spectroscopy. This comprehensive book has an accompanying CD-ROM and is at once a "primer" for comet hunters and a reference text for more advanced amateur astronomers.

Comets are celestial objects that orbit the sun. They're comprised of frozen gases, rock, and dust. When a comet hurtles near the sun, its dusts and gases heat up and form a halo and a tail. Your intrepid explorers will learn the scientific history of discovering and identifying comets and the difference between comets and other space objects. Photographs and artist renderings of comets and their paths help readers understand these amazing astronomical phenomena.

As this excellent book demonstrates, the study of comets has now reached the fas cinating stage where we understand comets in general simple tenns while, at the same time, we are uncertain about practically all the details of cometary nature, structure, processes, and origin. In every aspect, even including dynamics, a choice among several or many competing theories is made impossible simply by the lack of detailed knowledge. The space missions, snapshot studies of two comets, partic ularly the one that immortalizes the name of Sir Edmund Halley, have produced a huge mass of valuable new infonnation and a number of surprises. Nonetheless, we face the tantalizing realization that we have obtained only a fleeting glance at two of perhaps a hundred billion (lOll) or more comets with possibly differing natures, origins, and physical histories. To my personal satisfaction, comets seem to have discrete nuclei made up of dirty snowballs, as I concluded four decades ago, but perhaps they are more like frozen rubbish piles.

THE MEETING The IAU Symposium 160 ASTEROIDS COMETS METEORS 1999 has been held at Villa Carlotta in Belgirate, on the shore of Lago Maggiore (Italy), from June 14 to June 18, 1993. It has been organized by the Astronomical Observatory of Torino and by the Lunar and Planetary Institute of Houston. It has been a very large meeting, with 323 registered participants from 38 countries. The scientific program included 29 invited reviews, 106 oral communications, and 215 posters. The subjects covered included all the aspects of the studies of the minor bodies of the solar system, including asteroids, comets, meteors, meteorites, interplanetary dust, with special focus on the interrelationships between these. The meeting was structured as follows. 5 morning plenary sessions have been devoted to invited reviews on: (1) search programs (2) populations of small bodies (3) dynamics (4) physical observations and modelling (5) origin and evolution. Two afternoon plenary sessions have been devoted to space missions to small bodies and to interrelationships between the different populations. The afternoon parallel sessions have been devoted to: dynamics of comets; Toutatis, Ida, Gaspra; physical processes in cometary comae and tails; meteorites; the cosmogonic message from cometary nuclei; physics of asteroids; the interplanetary dust complex; comet nuclei; meteors; composition and material properties of comets; dynamics of asteroids.