A fascinating book by Peter D. Ward and Donald Brownlee which defies the myths of popular culture by explaining, scientifically, why Earth may be unique after all.

For the last several decades, after scientists caught their first glimpse of the uncountable number of galaxies and trillions of stars surrounding the milky way, and after realizing just how insignificant Earth seemed to be in light of the vastness of the universe – it has become common knowledge that there must be other life out there, somewhere.

After all, what is Earth that it would be so fortunate to be the only planet in such a vast universe to hold intelligent life?

With that in mind, humans have been searching the skies for any trace of extraterrestrial life. Any sign that they are not alone in the universe. After all, it’s only a matter of time, is it not?

Why Life is Uncommon

According to Peter Ward and Donald Brownlee, Science Professors at the University of Washington in Seattle, it may not be just a matter of time, because there very well may not be any complex life out there at all (besides on Earth, of course).

This book, which retains scientific credibility throughout (no unwarranted speculation or personal author bias is readily evident), takes the reader step by step through an explanation of just how difficult it truly would be for life as it is currently understood to arise in the universe.

While Carl Sagan and Frank Drake famously used the “Drake Equation” to estimate how many habitable planets might exist within the universe, “Rare Earth” is a re-examination of these principles, and concludes that there are many factors that Sagan and Drake did not include when coming to their conclusion.

Step by Step

Rare Earth contains a great deal of very detailed scientific reasoning, mixed in with a refreshing dose of narrative to help the complexity of the topic go down a bit easier.

Beginning with the qualifying assumption that while “life” in its most simple forms (such as extremophiles or proteins) may very well turn out to be widespread in the universe, assuming that the same can be said for complex life is much more difficult.

Rare Earth follows along a very clear, precise form of reasoning to achieve its groundbreaking conclusions – from the strict requirements regarding a star’s “habitable zone,” to the dangers and frequency of mass extinctions, to the necessity of a moon precisely the size of Earth’s moon, to the necessity of Jupiter, to the absolute requirement of plate tectonics for a planet to become habitable by complex organisms.

This book makes a strong argument for each of its propositions, and in the end, does an excellent job of persuading the reader that, while it may be possible for life to exist elsewhere in the universe, it certainly isn’t anywhere near as probable (or as certain) as many scientists and laymen alike have been led to believe.

Conclusion

While this book will certainly appeal to a standard “popular science” audience, the prose and often daunting science of it does have the potential to turn off readers who are seeking to be entertained, and not necessarily be called upon to think.

For anyone willing to truly stretch their intellect and to learn something new about the universe and about life itself; or for those who desire simply to fully appreciate the good fortune of humanity to have a planet like the Earth – this is an excellent, rewarding and enlightening read.

Book Details

“Rare Earth: Why Complex Life is Uncommon in the Universe”

Peter D. Ward and Donald Brownlee, 2000 (hardcover), 2004 (paperback)

Copernicus Books

ISBN: 0-387-95289-6