Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization
© 1975-1979, 2008 Robert A. Freitas Jr. All Rights Reserved.
Robert A. Freitas Jr., Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization, First Edition, Xenology Research Institute, Sacramento, CA, 1979; http://www.xenology.info/Xeno.htm
8.1 The Argument for Diversity
The word chauvinism is derived from the cognomen of a highly jingoistic French soldier by the name of Nicolas Chauvin, born at Rochefort in the late 18th century. In 1815 Chauvin gained great notoriety by his obstinate, bellicose attachment to the lost cause of Napoleon’s crumbling imperium. The term has since become identified with the absurd, unreasoning, single-minded devotion to one’s own race, nationality, sex, or, most recently, to one’s own point of view.
Chauvinisms are predictably common in xenology. For example, we have argued against what might be called "G-star chauvinism," the idea that a home sun exactly like Sol is a prerequisite for life.15 Although our sun is class G, F stars and K stars undoubtedly are also hospitable to life. But stars may not be necessary at all. The possibility exists that interstellar space may contain a large number of starless planets, objects having jovian or superjovian mass. Neglecting such an alternative could be condemned as "solar chauvinism."1470
There have been discussions of "planetary chauvinism," the belief that life can only exist on the surface of planets. Fred Hoyle exposes this parochialism in his science fiction novel The Black Cloud. After humans manage to open a communications link with the gaseous lifeform, the interstellar electromorph is quite astonished. "Your first transmission," says the Cloud, "came as a surprise, for it is most unusual to find animals with technical skills inhabiting planets -- which are in the nature of extreme outposts of life."62
And atmospheric chauvinism? Carl Sagan has imagined organisms trapped on a planet whose air is slowly leaking away to space. Over time, such creatures might evolve mechanisms to cope with what is essentially an interstellar environment.15 Another possibility might be an advanced spacefaring civilization that had set up outposts in deep space or on airless worlds.
There are many biochauvinisms in xenology, various preconceptions relating to indigenous alien lifeforms. For instance, one biochauvinism this author finds exceedingly difficult to overcome is "phase separation chauvinism."2371,2393 The requirement that all organisms must retain some sort of boundary layer between themselves and their surroundings seems to follow directly from the basic thermodynamic nature of life processes.
Other things seem not so fundamental. The extremes of life on Earth are well documented; microorganisms are especially hardy.
Acontium velatum and Thiobacillus thiooxidans flourish in some of the strongest acids known (pH = 0.0), while a blue-green algae known as Plectonema nostocorum thrives in the strongest bases (pH =13.0). (Normal water is neutral, with pH = 7.0).
Microbes can tolerate poisons of many kinds in their environment, such as corrosive sublimate (mercuric chloride), sulfuric acid, and arsenic. The tardigrades can stand prolonged periods of virtually complete desiccation,* and organisms have survived pressures ranging from the vacuum of space to more than 8000 atm (the barotolerant deep sea bacteria).
Growth and reproduction have been demonstrated from -24 °C (psychrophilic bacteria) up to 104 °C, and a few organisms (tardigrades, spores) have been frozen to near absolute zero, or heated to more than 120 °C, and survived the ordeal.
Radiation resistance is low in mammals and other higher lifeforms -- whole body lethal dose for man is a few hundred roentgens. But Deinococcus radiodurans and certain algae have endured as much as ten million roentgens of neutron bombardment, owing in part to special protective chemicals contained within their cells. Ultraviolet chauvinists claim that life is impossible on Mars because of the intense, unshielded solar radiation (UV) there, but many protective adaptations readily can be imagined.15,26,1238
Perhaps one of the most persistent biochauvinisms is "oxygen chauvinism." A few decades ago, before the matter was given the serious thought it deserves, it was alleged that any planet lacking this "vital" gas was ipso facto uninhabitable. However, O2 is not a requirement for survival for many organisms alive on Earth today (e.g., yeasts, tetanus bacillus, etc.) and was not present in appreciable quantities on the primitive Earth when the origin of life occurred.
It has been shown that the present level of O2 is not optimal for plant growth. Greenery evidently grows more luxuriantly in an atmosphere containing only about half the normal amount of oxygen.53 Human scuba divers are poisoned by the pure gas at more than a couple atmospheres of pressure. The presence of O2 in the nuclear regions of contemporary living cells is usually fatal.
Oxygen is basically a reactive, toxic gas which chemically combines with and degrades virtually all useful biomaterials. The disastrous and widespread contamination of Earth’s atmosphere with O2 a few eons ago (the first real "smog crisis") might have spelled the end of life on this world had nature not been able to quickly readjust to the new situation. It is as Arthur Clarke says: "Oxygen needs life," rather than the other way around.609
The mere absence of oxygen on a planet cannot, by itself, argue against the presence of life there.
Perhaps a more general biochemical question is whether or not the chemistry of life must occur in the liquid state. Most biologists would probably insist on a liquid solvent.
But life in the gaseous state cannot categorically be ruled out. One can imagine a "soap-bubble beast," laced with innumerable compartments and sub-compartments throughout. Probably a creature of the air, its metabolism might consist of chemical redox reactions taking place within its many "cells" in a controlled manner with the reaction products slowly diffusing outward. Because of the lower concentration of chemicals in such a gaseous medium, the organism’s structure, complexity, size and behavior would be sharply limited.
Solid life, too, is not out of the question. Although it has been alleged that reaction rates would be too slow for such lifeforms to exist, we know that timescales are relative and highly subjective. Trees often take hundreds of years to grow to full maturity, and many are thousands of years old. There is nothing a priori absurd in positing a form of life which has extremely slow negentropic processes.
Of course, it must be admitted that the liquid phase seems rather more convenient than the solid, gaseous or plasmic phases. Ions form easily, transport is greatly simplified, the breakup and recombination of chemical bonds is facilitated, and crude environmental stability is assured. The liquid phase is probably the preferred mode of existence for extraterrestrial lifeforms.
* The kangaroo rat, a common resident of American deserts, never needs to drink water. Its metabolism breaks down chemical compounds in sufficient quantities to enable it to live on the water manufactured from the food it eats. Other animals, such as the flour beetle, are known to have similar abilities, and camels can sustain themselves for weeks in this fashion. In the plant world, the Spanish moss can grow without contact with any groundwater -- when humidity is high, it can extract the needed moisture directly from the air.
Last updated on 6 December 2008