Although the development of ideas about the motion and trajectory of comets has been investigated piecemeal, we lack a comprehensive and detailed survey of ph- ical theories of comets. The available works either illustrate relatively short periods in the history of physical cometology or portray a landscape view without adequate details. The present study is an attempt to review - with more details - the major physical theories of comets in the past two millennia, from Aristotle to Whipple. My research, however, did not begin with antiquity. The basic question from which this project originated was a simple inquiry about the cosmic identity of comets at the dawn of the astronomical revolution: how did natural philosophers and astronomers define the nature and place of a new category of celestial objects - comets - after Brahe's estimation of cometary distances? It was from this turning point in the history of cometary theories that I expanded my studies in both the pre-modern and modern eras. A study starting merely from Brahe and ending with Newton, without covering classical and medieval thought about comets, would be incomplete and leave the fascinating achievements of post-Newtonian cometology unexplored.
From the reviews:Until very recently, comets have been consistently misunderstood and often considered as flaming apparitions thrown at a sinful Earth from the right hand of an avenging God. Today they are considered as icy remnants of the solar system formation process - but still capable of striking Earth. Dr. Heidarzadeh has provided a comprehensive, scholarly and yet interesting history as to how comets have been perceived from ancient times through the mid twentieth century. It is highly recommended for scientists and layman alike." Donald K. Yeomans, Senior Research Scientist at the California Institute of Technology's Jet Propulsion LaboratoryHeidarzadeh's book offers a comprehensive, scholarly survey of physical theories of comets from antiquity to the present day. He offers considerable new detail on Newton's theories and their reception, a topic that has received surprisingly little attention. And he also covers the crucial period in which Laplace and his contemporaries reduced comets from the size of planets to near the size we believe they are today. This is a remarkable trove of information to find in a single book, and it will be invaluable to anyone interested in the history of the physical sciences and especially the history of astronomy and cosmology. -- Peter Barker, University of Oklahoma"Tofigh Heidarzadeh covers over two thousand years of cometary theory in this book. ... does a fine job of examining how theories about the natural world combined with theories about comets ... . this book is a valuable and original addition to the literature on the history of astronomy. It provides useful images and tables and Heidarzadeh's descriptions ... are detailed and clear. His book ... will appeal to both the specialist and to those new to the topic." (Elizabeth Burns, Journal for the History of Astronomy, Vol. xli, August, 2010)