Paul Davies’s subtitle might lead readers to suspect that he is one of the band of scientists out to prove the existence of God. This idea will be dispelled quickly as readers delve into the searching questions that Davies raises and into the scientific evidence he brings to this extraordinary study. Although he deals with extremely complex biogenetic and astronomical material, he writes with sufficient lucidity and vigor that reading The Fifth Miracle is akin to reading a fast-moving, compelling adventure story.
Davies, a theoretical physicist with over twenty books to his credit, was raised and educated in the environs of London, but now lives in South Australia. His guiding principle, stated well into the book, seems to be “the dictum that the absence of evidence is not the same as evidence of absence.” He approaches his subject with a healthy skepticism but always with a mind sufficiently open that it does not confuse absence of evidence with evidence of absence.
This attitude has led him to state the probability that there is life on Mars, and, possibly, on other planets as well. At present, conditions on Jupiter’s moon Europa appear to favor the presence of life on that planet, and the very vastness of space offers the possibility that life once existed or currently exists on planets other than Earth.
One must be cautioned that when Davies writes about life on Mars, he is not suggesting the presence of little green people with antennas protruding from their foreheads. He is talking about much lower forms of life, the very forms that inhabited the primordial ooze on Earth during its formative stages. Once these forms have been established, it may be merely a matter of time before more complex forms evolve, although all sorts of variables must be in place before this can happen.
In a most compelling chapter entitled “Mars: Red and Dead?” which for many will be the most interesting chapter in a thoroughly enticing book, Davies offers persuasive evidence that Mars, known to have had, far back in its history, both water and a relatively mild climate, may once have supported life. He goes so far as to speculate that certain life-forms, particularly bacteria, may still exist in the depths of the planet far below its ice caps, which may contain areas heated geothermally from the planet’s core.
In support of these highly controversial speculations, Davies cites the conclusions that Mars expert Chris McKay, who works as a researcher for the National Aeronautics and Space Administration (NASA), reached regarding the presence of petrified husks of microbes in a rock, ALH84001, that has definitely been identified as being from Mars. It has been established that it fell into Antarctica near Allan Hills some thirteen thousand years ago following an estimated sixteen-million-year journey through outer space. Roberta Score, a member of the United States Antarctica Search of Meteors team in 1984, found ALH84001 lying on the edge of an ice field.
The rock had never been touched by human hands and was fully protected from contamination before it was sent to Houston under frozen conditions for analyses that have continued during the intervening years. More sensitive instruments and a greater understanding of Mars and of outer space have provided increasingly sophisticated means of conducting the ongoing analyses.
Davies is well aware of the major arguments that some of his fellow scientists have formulated casting doubt on his contentions, but he responds to such arguments with verifiable scientific facts that generally counter, and at times obliterate, his opponents’ skepticism. In writing about the meteorite that fell near the Australian town of Murchison on September 28, 1969, and has been subjected to extensive scientific analysis ever since, he concludes categorically:
There are objects in space loaded with just the sort of organic compounds needed for life to get started. It does not require a primordial soup on Earth to synthesize the building blocks of life. These substances can fall from the sky, ready-made.
Analyses of the Murchison meteorite support Davies’s speculative theory that early forms of life may originally have come to Earth from other planets and, finding a hospitable environment, have flourished to the point of development that life on this planet has eventually reached. He cautions that one must not assume that life can exist only under conditions that are known to support life as most people know it. He refers to the vents in the bottom of Earth’s oceans that spew forth water at close to a thousand degrees Fahrenheit, but that have living organisms growing around them in heat that most people would consider much greater than that in which...
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