Here be Dragons
The Scientific Quest for Extraterrestrial Life
David Koerner and Simon LeVay
264 pages including index
published in 2000
Perhaps the greatest unanswered question for science is whether or not there's life beyond the boundaries of Earth. Here Be Dragons is an overview of the current state of affairs in resolving this question. What makes this book interesting is the way in which so many different fields in cosmology are tied together in the search for extraterrestial life.
Here Be Dragons starts off its quest by looking at how life originated on Earth and how life managed to spread everywhere, even under the most extreme conditions on the planet from the icy wastes of Antarctica to the heat scorched rocks of Death Valley. It also looks at the results in the search for life elsewhere int he solar system, paying particular attention to (whatelse) Mars. Some hypotheticals for life on Europa are also laid out. This all in the first three chapters.
The next two chapters seemingly take a detour from the search for extraterrestial life and look at the origin and life of stars, how solar systems and planetary systems are formed, then at the evidence for extrasolar planets. If planets routinely accompany stars, the chances of extrasolar life obviously soar. Similary, the type of star around which planets form is also important as is the question of whether organic molecules observed in outer space could survive the formation of a planetary system and help create a basis for life to arise from.
With the first discoveries of extrasolar planets in the last decade, the argument for extrasolar life got a big boost. At the moment what has mainly been discovered are jovian or superjovian planets, mostly because the methods for planet detection are still so primitive - but NASA and others have big plans.
The next step in determining the chances of extraterrestrial lifes is one of evolution. If evolution is difficult and dependent on contingency, the chances are low it will lead to life (at least recognisable life) elsewhere. If evolution is guided by (so far undiscovered) natural laws chances are it will lead to roughly similar life around other stars. Evidence for either of the two positions is inconclusive.
In the next chapter we finally come to SETI, the Search for ExtraTerrestrial Intelligence. This is done by various listening programs at several radio telescopes. I've always been a supporter of this: it's cheap and simple and the possible payoff is big enough to justify the costs. Others are more sceptical, thinking that advanced civilisations may have stopped using radio altogether, or even doubting alien intelligences could exist. If they do exist, why aren't they here?
Beyond this, the last three chapters handle the more exotic aspects of the search for extraterrestrial life: UFOlogy, exotic ways in which life could evolve (AI e.g.) and finally advanced theories of cosmology. The latter to partly answer the question of why our univers seems so eminently suited for life. Personally I always thought this was because life adapted to the universe, not that the universe itself was created so that life could arise.
For anybody interested in the question of extraterrestrial life, this book will have little new to tell. What makes it a worthwhile read is the way in which it brings together various topics. Extrasolar planets, string theory, the existence of clouds of organic molecules in deep space, etc, etc: I knew about them, but they existed for me as unconnected pieces of trivia. The great strength of this book is in typing all these pieces together in a coherent whole. In doing this, it went beyond the question it set out to answer.
