Brief

After hearin' many opinions statin' that thar are many intelligent civilizations in t' Milky Way Galaxy I thought it would be fun t' hear t' opposin' viewpoint.  I was nay disappointed.  With t' number o' newly discovered exo-planets increasin' everyday these speculations and view points will become more apparent in t' public awareness in t' years ahead.   I have seen a calculation usin' t' Drake equation showin' that thar are 10,000 intelligent civilizations in our galaxy alone.  Mr. Arrr! Gribbin feels that some o' t' factors in this equation have been set way too high.  In fact his interpretation is that t' number o' planets in t' Milky Way Galaxy is much lower.  T' number is one and we are that planet.  T' idea that we are alone is nay new.  Enrico Fermi stated t' premise many decades ago.  If thar are so many planets with intelligent civilizations, then where are they?

T' book is relatively short at about 205 pages and easy t' read.  I found many familiar concepts that I have read about in recent years in me favorite magazines Astronomy and Scientific American have been reviewed and used in t' book.  For example, arrr, me hearties, in general stars with elements heavier than helium (usually referred t' as metallic elements in this context) that are important for buildin' life are found only in t' inner part o' t' Milky Way Galaxy at about 20,000 light years from t' center.  T' rest o' t' galaxy tends t' be deficient in these higher elements.  T' author goes on t' say that thar may be many planets that are t' right distance from their sun t' be in t' habitable zone for life, matey, but they need t' be in that zone for a very long time and that zone in general moves with time.  Then, too, thar may be planets that have life, me hearties, but they may nay have intelligent life. 

Other factors that make our planet unique are its iron core and t' resultin' beneficial magnetic field along with our relatively large moon that helps lock in a beneficial stable long-lived rotation.  Oddly enough, arrr, t' events that helped formed these features may be related.  Our solar system be created about 4 billion years ago, but life exploded only about 500 million years ago durin' t' Cambrian era.  Prior t' that explosion o' life on earth only consisted o' single cell creatures, shiver me timbers, t' prokaryotes and t' eukaryotes, me hearties, and t' prokaryotes didn’t even have a nucleus.  T' oceans had these single-celled life forms for several billion years durin' t' Pre-Cambrian era and suddenly t' sophistication o' life took off.  Why?  And if more sophisticated life did nay arrive, then intelligent life on earth would nay have happened.

Durin' t' course o' creatin' our planet t' impact o' small asteroids and comets may have helped deliver water t' our biosphere.  T' timely arrival o' these impacts may have also triggered new branches o' evolution.  However, ya bilge rat, on an evolutionary time-scale how can one say that all impacts are beneficial?  Maybe these impacts may be beneficial or fortuitous for evolution.  On t' other hand, ya bilge rat, such collisions might be t' end o' all life on a planet.

This is an interestin' book with some interestin' closin' remarks.  We may be alone in t' universe and we should appreciate what we have.