Astronomy: The Evolving Universe - Michael Zeilik

Zeilik's book is one of the earliest systematic astronomy texts I ever read, beginning with the third edition back in 1982. That edition had four primary sections – Part I: Changing Concepts of the Cosmos; Part II: The Planets, Past and Present; Part III: The Universe of Stars and Galaxies; and Part IV: Cosmic Evolution.

Part I looks at the general structure of the universe, how it was conceived in the past, and how it is viewed today. ...
...general heading of cosmology. Zeilik has an interest in the history of astronomy, and it shows clearly in the text. He explores, among other topics, the Anasazi prehistoric astronomy discoveries, the Ptolemaic geocentric model, Tycho Brahe/Kepler's achievements, the discoveries of Newton and Galileo, and finally the birth of modern astrophysics. Some basic physics is introduced along the way, to make sense of radiation and optics, as well as gravitation ... more

Zeilik's book is one of the earliest systematic astronomy texts I ever read, beginning with the third edition back in 1982. That edition had four primary sections – Part I: Changing Concepts of the Cosmos; Part II: The Planets, Past and Present; Part III: The Universe of Stars and Galaxies; and Part IV: Cosmic Evolution.

Part I looks at the general structure of the universe, how it was conceived in the past, and how it is viewed today. Much of what is covered here falls under the general heading of cosmology. Zeilik has an interest in the history of astronomy, and it shows clearly in the text. He explores, among other topics, the Anasazi prehistoric astronomy discoveries, the Ptolemaic geocentric model, Tycho Brahe/Kepler's achievements, the discoveries of Newton and Galileo, and finally the birth of modern astrophysics. Some basic physics is introduced along the way, to make sense of radiation and optics, as well as gravitation and space-time concepts.

There is a good deal of history in this section, which makes the study of science generally, through the lens of astronomy, part of the overall cultural development of civilisation. This involve both the development of observations and the development of ideas; the reader will get a sense of how technological advances and advancement in the realm of theory and ideas goes hand-in-hand. Telescopes are only one of the tools of the trade. The shift from a geocentric (earth at the centre) universe to a solar-centric (sun at the centre) to the galaxy to the local group of galaxies and beyond had great impact on how human beings have perceived their place in the universe.

Part II looks at the nine planets of our solar system, including their satellites (moons), and the asteroids and other solar system objects (comets, etc.). Planetary sciences are among the fastest developing sciences around, so a lot of the information contained here is basic, and some updating is required. There is no mistake that the most current version of this text is now in its ninth edition. The final chapter in this subject looks at some of the theories of the origin and development of the solar system.

There are broad categories here – the earth is in a class by itself, as the only inhabited world with a diverse ecosystem. Some celestial bodies (the moon, Mercury) are considered 'dead worlds'; some like Venus and Mars inspire science fiction because of their proximity and, particularly in the case of Mars, information about the details of the surface available to us early (the 'canals' on Mars have been known from telescopic observation for quite some time. The gaseous giants with rings and extensive satellite systems have inspired wonder since Galileo first saw the moons of Jupiter and the extensions on Saturn later identified as rings.

Part III looks at the universe beyond the planets, looking first at the sun as a typical small star, and then going further afield to look at the Milky Way, our local galaxy in some detail. This includes a look at other major formations and stars within the galaxy – some named stars of interest as well as celestial objects such as nebulae, and a discussion of interstellar distances and distribution (Hertzsprung-Russell diagram, etc.). The structure, kinematics and dynamics of spiral galaxies are explored, and then other types of galaxies (elliptical, etc.) and galactic clusters.

The final section, Part IV, looks at general evolution and development of the universe. Stellar evolution is the first subject, as one of the primary vehicles of universal development. The different ways in which a star dies are explored – white dwarves, neutron stars, supernovae, black holes, pulsars. The larger ideas of the origins and ultimate fate of the universe (cosmology again, at the end) are explored, including a brief discussion of the origins of life in the universe, and short discussions on topics such as SETI (called CETI here, Communication with ExtraTerrestrial Intelligence).

These last two sections look at the universe on the broadest possible scale, reaching back in time and forward into the future. This is point of science that edges close to philosophy and theology, as we reach the limits of what observation and theoretical science can deliver. The origins of the universe and the origins of life are explored separately and then connected; some elements of biology and chemistry enter in here. The possible ramification for future development are also discussed – what happens at the end of the universe, or does it go on forever? Is there an end of time?

One of the useful aspects of this text is the 'Beyond the Book' sections after each chapter. These include information about periodicals (often the best way to find the latest information on astronomy topics), additional books and other resources. There are learning objectives listed at the beginning of each chapter, and convenient summaries, and some short exercises at the end of each chapter also.

There are several useful appendices, including lists of stars, planetary data, periodic table, and other such information. A very good glossary and index round out the book, making it an excellent text book for both classroom and independent use.

Being someone who likes history and large-scale ideas in philosophy and theology, the first and final sections are my favourites. With the continuing exploration of the planets, new data is being accumulated to change our perceptions of the planets – this book has a 'Saturn Update' to incorporate some more recent discoveries; in future editions of the book I would expect other updates from later planetary probes. Similarly, we are on the edge of radical new formulations about the structure and origins of the cosmos; some of these ideas are too new for incorporation into current textbooks, but understanding the common-held situation provides a good grounding for understanding the most recent theories, some of which may prove incorrect, but some of which may lead to new ways of thinking that could once again change our perception of who we are as a people in the universe.
 

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