Titles | Authors | Subjects

David Koerner and Simon LeVay


The Scientific Quest for Extraterrestrial Life

Book review by Anthony Campbell. Copyright © Anthony Campbell (2002).

One of the authors (Koerner) is an astronomer, the other (LeVay) a biologist. Together they set off to interview a wide range of people with opinions about the likelihood or otherwise of life outside our planet. The book is aimed at a "general" audience and is very readable; it provides a pretty up-to-date review of the subject.

The book begins with a rather tongue-in-cheek account of a visit to the Museum of Creation and Earth History, devoted to a Biblical fundamentalist view of the matter. Fortunately there isn't much of this, and we then pass on to the opposite extreme, with a discussion of scientific attempts to explain how life may have originated on the Earth. In spite of a good deal of theorizing and experimentation, no firm conclusions about this are possible, and it may be that life did not originate here at all but was seeded from outer space (which, of course, would simply push the mystery back in time without actually solving it).

Of all the planets in the solar system apart from Earth, only Mars seems to have a reasonable prospect of harbouring life, either now or in the remote past. However, even if life is found on Mars, it could have arrived there from Earth via meteorites; the reverse is also possible. In neither case would we know whether life could have developed completely independently. If Mars turns out to be sterile, Europa (one of the moons of Jupiter) might be an alternative site for life, and so might Titan, one of the eighteen moons of Saturn.

If none of these turn out to have any form of life, what about other solar systems? How common is it for planetary systems to develop when stars form? Koerner is in a good position to write about this because he has made a special study of the evolution of circumstellar disks. Large gas planets like Jupiter have been detected orbiting stars but it is still uncertain how frequently hard rocky planets like the Earth will form. Improvements in technology will soon be able to provide more authoritative answers to the question, and the techniques are described in some detail.

Turning from astronomy to biology, the authors ponder how likely it is that life, once started, will lead to more complex forms and ultimately to intelligence. Some, like the late Stephen Jay Gould, hold that there is no particular reason to expect intelligence to arise, while others think there is a more or less inevitable trend in that direction. The authors give a lot of space to Stuart Kauffman, who for many years has been applying sophisticated mathematical techniques to evolution. His work suggests that there are definite patterns in the way systems, including living systems, evolve, but some biologists find these ideas to be abstract and unconvincing.

If intelligent life does exist elsewhere in the galaxy, perhaps we can detect it directly. SETI (Search for Extraterrestrial Intelligence) is regarded as dubiously scientific by some critics, such as the astronomer Ben Zuckerman; and the SETI Institute ceased to receive federal government aid in 1993. However it still receives a lot of private support and its work continues. The SETI@home project was still at the planning stage when this book was written though it is now in operation.

Reverting once more to the fantasy realm for a bit of light relief, the authors look briefly at the UFO phenomenon. The book concludes with a couple of chapters on possible life forms not based on carbon and on the anthropic principle (is the universe in some sense designed for life?). They seem fairly unconvinced by claims that modern cosmology provides evidence for a Creator and conclude by quoting Steven Weinberg's opinion: "The more we learn about the universe, the more it seems to me that it is not governed by any principle in which morality or human life or love or justice, play any special role."

In a final section the authors offer their own conclusions. After reviewing the evidence they stick their necks out and say that they think "the search will be rewarded, and soon". We shall have to see; I have to admit to being somewhat less sanguine myself, even though I have SETI@home running on my computer (after all, you never know).

Regular readers of scientific books and magazines will not find much here that they did not know already, but the authors' discussion is balanced and skeptical and it is convenient to have the main facts and arguments collected together. There are suggestions for further reading at the end of each chapter and sources are provided in the notes.

%T Here Be Dragons
%S The Scientific Quest for Extraterrestrial Life
%A Koerner, David
%A LeVay, Simon
%I Oxford University Press
%C New York
%D 2000
%G ISBN 0-19-512852-4
%P 264 pp
%K science, cosmology
%O illustrated
Titles | Authors | Subjects