For a moment, I want you to think of your favorite alien on TV or in the movies. Do you have the image in mind? I'd bet that your alien is pretty darn smart. However, despite what we see in Star Wars and Star Trek, I don't expect intelligence to be an inevitable result of evolution on other worlds. Since the beginning of life on Earth, as many as 50 billion species have arisen, and only one of them has acquired technology. If intelligence has such has high survival value, why are so few creatures intelligent? Mammals are not the most successful or plentiful of animals. Ninety-five percent of all animal species are invertebrates. Most of the worm species on our planet have not even been discovered yet, and there are a billion insects wandering the Earth. If humankind were destroyed in some great cataclysm, there is very little possibility that our level of intelligence would ever be achieved on Earth again. The historian of science C. Owen Lovejoy regards cognition as a pure accident: "It is evident that the evolution of cognition is neither the result of an evolutionary trend nor an event of even the lowest calculable probability, but rather the result of a series of highly specific evolutionary events whose ultimate cause is traceable to selection of unrelated factors such as locomotion and diet." If human intelligence is an evolutionary accident, and mathematical, linguistic, artistic and technological abilities a very improbable bonus, then there is little reason to expect that life on other worlds will ever develop intelligence as far as we have. Both intelligence and mechanical dexterity appear to be necessary to make radio transmitting devices for communication between the stars. How likely is it that we will find a race having both traits? Very few Earth organisms have much of either. As evolutionary biologist Jared Diamond has suggested in Natural History, those that have acquired a little of one (smart dolphins, dexterous spiders) have acquired none of the other, and the only species to acquire a little of both (chimpanzees) has been rather unsuccessful. The most successful creatures on Earth are the dumb and clumsy rats and beetles, which both found better routes to their current dominance. If we do receive a message from the stars, it will undermine much of the current thinking about evolutionary mechanisms.


One of evolution's most fascinating enigmas is why Earthly creatures prefer to form their proteins from just one of two types of building blocks. Amino acids, the subunits of proteins, come in two mirror-image shapes that have identical chemical compositions but differ from each other much like your left hand differs from your right. In fact, when amino acids are created in a laboratory, the batch invariably contains equal numbers of left- and right-handed molecules. Presumably the same was true inside the Earth's primordial ooze. So why did life favor the left-handed form? These questions are unanswered. If life originates from nonliving chemicals, there seems to be no convincing reason for one amino acid form to be selected and not the other. In 1997, researchers discovered that the predominance of one amino acid shape isn't unique to life on Earth: It also shows up in meteorites dropping from outer space. Much of the recent research focuses on a meteorite that fell to Earth in 1969, near Murchison, 80 miles north of Melbourne, Australia. The Murchison meteorite is a "carbonaceous chondrite." It is generally believed to be a remnant of a spent comet. The meteorite contains 55 amino acids that have no terrestrial counterparts. Eight of the 23 amino acids occur in proteins on Earth. The recent discovery that an excess of one mirror form of amino acid did not evolve on Earth, as many scientists had believed, suggests that the asymmetry may have been the result of chemical processes in interstellar gases at the time the solar system was formed. Still, it is possible that ancient Earth contained equal amounts of the two amino acid forms, labeled L and D, and that evolution eventually resulted in the dependence of most organisms on the L form. It is also possible that before life began on Earth, the chemical soup already contained mostly L amino acids, and organisms evolved to use that form. No matter what the source, new findings make it difficult to discriminate between organic compounds produced by Earthly organisms and those produced by aliens elsewhere in the solar system. Researchers have long hoped that the preponderance of L amino acids would be a fingerprint for Earthlings. But if the chemical asymmetry was laid down before the evolution of all life, then aliens may bear the same fingerprint.
CyberDroid