Free The Cosmic Serpent by Jeremy Narby

suggesting that the molecule of life was of extraterrestrial origin—in the same way that the “animist” peoples claimed that the vital principle was a serpent from the cosmos.

    Cover of Crick (1981), reproduced with permission from Little, Brown & Co.
    I had never heard of Crick’s hypothesis, called “directed panspermia,” but I knew that I had just found a new correspondence between science and the complex formed by shamanism and mythology.
    I sat down in the armchair and plunged into Life itself: Its origin and nature .
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    CRICK, writing in the early 1980s, criticizes the usual scientific theory on the origin of life, according to which a cell first appeared in the primitive soup through the random collisions of disorganized molecules. For Crick, this theory presents a major drawback: It is based on ideas conceived in the nineteenth century, long before molecular biology revealed that the basic mechanisms of life are identical for all species and are extremely complex—and when one calculates the probability of chance producing such complexity, one ends up with inconceivably small numbers.
    The DNA molecule, which excels at stocking and duplicating information, is incapable of building itself on its own. Proteins do this, but they are incapable of reproducing themselves without the information contained in the DNA. Life, therefore, is a seemingly inescapable synthesis of these two molecular systems. Moving beyond the famous question of the chicken and the egg, Crick calculates the probability of the chance emergence of one single protein (which could then go on to build the first DNA molecule). In all living species, proteins are made up of exactly the same 20 amino acids, which are small molecules. The average protein is a long chain made up of approximately 200 amino acids, chosen from those 20, and strung together in the right order. According to the laws of combinatorials, there is 1 chance in 20 multiplied by itself 200 times for a single specific protein to emerge fortuitously. This figure, which can be written 20 200 , and which is roughly equivalent to 10 260 , is enormously greater than the number of atoms in the observable universe (estimated at 10 80 ).
    These numbers are inconceivable for a human mind. It is not possible to imagine all the atoms of the observable universe and even less a figure that is billions of billions of billions of billions of billions (etc.) times greater. However, since the beginning of life on earth, the number of amino acid chains that could have been synthesized by chance can only represent a minute fraction of all the possibilities. According to Crick: “The great majority of sequences can never have been synthesized at all, at any time. These calculations take account only of the amino acid sequence. They do not allow for the fact that many sequences would probably not fold up satisfactorily into a stable, compact shape. What fraction of all possible sequences would do this is not known, though it is surmised to be fairly small.” Crick concludes that the organized complexity found at the cellular level “cannot have arisen by pure chance.”
    The earth has existed for approximately 4.5 billion years. In the beginning it was merely a radioactive aggregate with a surface temperature reaching the melting point of metal. Not really a hospitable place for life. Yet there are fossils of single-celled beings that are approximately 3.5 billion years old. The existence of a single cell necessarily implies the presence of DNA, with its 4-letter “alphabet” (A, G, C, T), and of proteins, with their 20-letter “alphabet” (the 20 amino acids), as well as a “translation mechanism” between the two—given that the instructions for the construction of proteins are coded in the language of DNA. Crick writes: “It is quite remarkable that such a mechanism exists at all and even more remarkable that every living