The Extravagant Universe: Exploding Stars, Dark Energy, and the Accelerating Cosmos

Robert Kirshner's book, `The Extravagant Universe: Exploding Stars, Dark Energy and the Accelerating Cosmos', is another in a series of interesting texts on cosmology written essentially for those who are science-illiterate, or at least only somewhat informed, and who wish to know some of the key insights and discoveries of our time regarding astronomy. Particularly at the end of this text, where Kirshner explains the importance of this kind of scientific research (why would the government or private agencies want to spend money on research that has little if anything to do with addressing the desires of humanity, encapsulated by Kirshner, as wanting to `rich, safe and immortal'?) for the average person - it is not just for intellectual fancy or whim, but the long-term implications of understanding the universe can affect our lives in ways we can't even contemplate today.Kirshner's narrative looks at many of the key discoveries, controversies, and personalities of the field of astrophysics, theoretical physics and cosmology in the twentieth century. Kirshner lays the groundwork not with Einstein (as so many texts do) but rather goes behind Einstein to the earlier work of Gauss and Riemann, with mathematics that, at the time, would not have been considered useful in the ways Einstein's general relativity made it. Kirshner looks at observation (Hubble Telescope, observations of background radiation through various methods, etc.) as well as theoretical conjectures to show the strand of thinking from the early universal constructs to present day theories.Kirshner traces the history of recent astronomy and cosmology through researchers in history such as Einstein and Hubble as well as persons he knows personally and professionally at work in the field today. Particularly in the last half-to-third of the book, where Kirshner brings in this personal level of acquaintance with the people involved, the science comes alive in a very human way. Kirshner is good at showing the limitations, as well - sometimes you just get lucky, or your gifts complement others. With regard to Hubble and Hale, for example, Kirshner recounts the evidence that they did not really understand Einstein's general relativity or the mathematics of his cosmological thinking; nonetheless, they continued their observational researches, and when Hubble discovered the expansion of the universe, Kirshner states that you don't have to know all of the mathematical and technical details involved in science, but rather `you just have to face in the right direction and go forward' with those things that you can do!Some of the key concepts Kirshner develops include the life-cycle of stars, the overall shape and structure of the universe, the idea of dark matter/dark energy that has gone unknown for so long, and the ideas of reaching back to the origins of the universe and drawing conclusions for the acceleration of the universal expansion. Kirshner does not develop the areas of planetary

Most cosmologists long believed that the universe would expand at a decelerating rate. Contrary to this belief, two teams of astronomers independently announced in 1998 the observational results that indicated the accelerating expansion of the universe since about 5 billion years ago. One of the two teams was called the Supernova Cosmology Project and led by Saul Perlmutter of Lawrence Berkeley National Laboratory in California, and the other was the High-z Supernova Team led by Brian Schmidt of Mount Stromlo and Siding Springs Observatories in Australia and the author of this book, Robert Kirshner of Harvard-Smithsonian Center for Astrophysics.Before reading this book I already learned much about this astounding finding from the following books: Amir D. Aczel, "God's Equation" (1999); Donald Goldsmith, "The Runaway Universe (2000); and Mario Livio, "The Accelerating Universe" (2000). The person who read one or more of these books like me might think the earlier chapters of "The Extravagant Universe" not so attractively written. As distinct from the other authors, however, Kirshner includes some passages useful to students and young scientists. For example, he writes in chapter 4, "You don't always have to understand the details of the mathematics to contribute to the advance of science"; and in chapter 6 he heuristically discusses various possible sources of observational errors.From chapter 9 on, the narrative becomes quite absorbing. We get such high excitement of the intellectual work leading to the discovery that can be conveyed only by the person who actually engaged in it. It is wonderful that mankind can learn something about the fate of the universe, though we do not yet know what dark energy, i.e., the source of acceleration, really is.I like the last pages of this book, on which the author describes why cosmology is important to us. Decision makers of science policy should read these pages at least. All the readers who are interested in the wonders of nature and the universe will surely be interested in this book. Vividly describing scientists' life filled with collaboration, competition, annoyance, confidence, etc., this is a good book especially for young people.

Professor Kirshner has provided a fascinating insight into the latest findings and conclusions associated with the investigation of the universe. Written in a non-technical way and sprinkled with humor, the average layman can understand the associated mathematics and physics. The Extravangant Universe will be a welcome addition to anyone interested in cosmology.

Bob Kirshner's book summarizes the exciting recent discovery of the accelerating Universe. Although as a professional astronomer I am familiar with the topic I could not stop reading this book. This is one of those rare books which give the reader a detailed insight into the hard and competitive work of a scientist who is always in danger of making a fool out of himself or isolating himself by not agreeing with the standard paradigm while at the same time being driven by curiosity and the joy and satisfaction of a new discovery. I recommend this book to everyone who wants to understand how scientists work and why this job is so fascinating for us.