Mars is the seventh in size among the planets of the solar system. Its diameter is 60 percent of earth's, but its mass is only 10 percent of our planet's. Once every 26 months we come as close as 35 million miles to Mars, and at such times the planet glows, with a reddish hue, more brightly than the brightest star. Viewed through a telescope, the Martian surface appears reddish-orange with irregular greenish patches and two glistening white polar caps. A number of astronomers, beginning with the Italian Schiaparelli in 1877, reported thin, artificial-looking lines ("canals") traversing the planet. To many, the greenish regions suggested the existence of vegetation, and the "canals" hinted the intriguing possibility of intelligent life on Mars.
Of all earth's neighbors in the solar system, Mars is considered to be most suitable to support life as we know it. The temperature of its surface is never excessively hot, never higher than 30 C.; and the average surface temperature is only 50 C. colder than on earth. Martian conditions are less severe than those of the boiling hot springs of Yellowstone National Park or of the water 30,000 feet below the surface of the Pacific Ocean, yet microorganisms have been found thriving in both of these areas. If life is there, under those conditions, why not also on Mars?
Between 1965 and 1972 a number of spacecraft were launched by the United States to obtain photographs of the red planet's surface from the proximity of a few thousand miles and to send back other information vital for a direct landing. The pictures revealed a desolate, comparatively featureless planet with craters, sand dunes, and ridges reminiscent of the lunar surface.
Telemetric data also indicated the presence of an atmosphere much thinner than ours, consisting mostly of carbon dioxide with some water vapor, carbon monoxide, oxygen, and atomic hydro gen. No traces of nitrogen, ammonia, or methane were found by the Mariner space probes.
The close-up photographs did not verify the existence of canals on Mars, nor were explanations obtained for the sup posed green areas of earlier, earth-based, observations. The absence of nitrogen and ammonia and the low water-vapor content of the Martian atmosphere discouraged speculation about the possibility of life there.
The theory behind the search
One currently popular postulate within the theory of evolution assumes that the initial processes that eventually led to the appearance of primitive life forms on our earth begin in the atmosphere of any planet that has the necessary ingredients and adequate radiation. The necessary ingredients of such a "life-producing" atmosphere, according to this postulate, are water vapors and gases containing carbon and nitrogen. Under the influence of ultraviolet radiation (or perhaps other energy sources), the components of this atmosphere combine to form bio logically significant compounds. Amino acids, simple sugars, and fats produced in this manner in the atmosphere collect on the surface of the planet. Given sufficiently long periods of time, these simple substances assemble themselves into proteins, complex sugars, nucleic acids, and eventually into living entities.
Laboratory experiments have been performed in which various mixtures of gases have been irradiated by ultraviolet or other types of radiation, and simple biologically important substances have indeed formed in this manner. These results have encouraged evolutionary theorists to elevate their theories to the level of dogma. In essence, they have been saying that given the proper ingredients of a planetary atmosphere, and the proper surface temperature and surface composition plus a few billion years, it is inevitable that life will appear on such a planet.
A perfect test case of the correctness of these theories would have been Mars, were it not for the reported absence of nitrogen-containing substances in the Martian atmosphere. Nevertheless, early in 1971 scientists at the Jet Propulsion Laboratory in Pasadena, California, exposed a gaseous mixture of carbon dioxide, water vapors, and carbon monoxide to ultraviolet radiation, and ob served the formation of formaldehyde, acetaldehyde, and glycolic acid. These organic molecules could potentially convert into biologically important sub stances if they interacted with the nitrogen of the Martian soil. Thus came the announcement from Pasadena that the existence of primitive life on Mars was possible.
A billion-dollar effort
This development paved the way for an all-out effort to find life on Mars. Several years of planning and instrument building and the expenditure of one billion dollars followed. Then, in the fall of 1975. two unmanned spaceships were launched from the Kennedy Space Center toward Mars. Each of the 7,700 pound Viking units contained a Mars-or biting satellite and a lander vehicle. The orbiter portion was equipped with two-way communication facilities, computers, solar-energy panels, jet-propulsion engines, and reservoirs of propellant fuel. The lander, a hexagonal-shaped, three-legged aluminum structure, housed computers, power units, cameras, and scientific instruments.
Cruising through space at about 30,000 miles per hour, the first spaceship touched on the Martian surface 335 days after the launching. Prior to landing, the spacecraft were placed in orbit around Mars. Potential landing sites were photographed by the orbiting vehicles for a closer look, and it was then that space scientists realized that the terrain of the initially selected site was too hazardous for a soft landing. Four weeks of intensive photographic search followed be fore a suitable spot was located on the Chryse Planitia basin. Then on July 20, 1976. at about 4:00 P.M. local Mars time, the Viking I lander successfully touched down close to the designated site and began transmitting data back to earth. A month and a half later, Viking II lander was also placed on Mars, at a region known as Utopia Planitia, some 4,600 miles from the location of the first robot. These lander vehicles had been designed to conduct significant chemical and biological experiments to test for the presence of life. Based on our experience with living matter here on earth, it is safe to generalize that living matter is relatively rich in the elements carbon and hydrogen, while in nonliving matter oxygen is relatively abundant. Among the instruments aboard the Viking I and II landers were combinations of gas chromatograph - mass spectrometers. These units could analyze the molecular and atomic components of gaseous sub stances.
The tests begin
A mechanical arm scooped up a small amount of Martian soil and placed it in an inner chamber. The soil was heated to 200 C. to drive off any relatively volatile substances, and the vapors were analyzed. Only water vapors were detected, believed to come from hydrated minerals in the soil. Next the soil was heated to 350 C. and then to 500 C. At these temperatures all carbon-containing molecules break down to gaseous fragments, suitable for analysis by the gas chromatograph- mass spectrometer units. The results of these experiments by both Viking units were negative. No carbon-containing substances were found in the Martian soil, within the sensitivity of these instruments, which was ten parts per billion. By comparison, surface samples from the biologically destitute regions of Antarctica have yielded some organic matter when similarly treated, of levels of several thousand parts per billion.
The subsequent experiments, designed to probe the biological activities of the Martian soil, Were anticlimactic, though their results were very surprising to scientists. One of these experiments tested the ability of the Martian soil to convert radioactively labeled carbon dioxide and carbon monoxide to larger carbon-containing substances both in the dark and in the presence of light. This is routinely done by some earthbound microorganisms and by all plants. Another experiment examined the ability of Martian-soil organisms to break down and metabolize compounds labeled with radioactive carbon. A third type of experiment consisted of monitoring the release of oxygen and other gases from soil samples, as they were incubated in a complex growth medium.
The results obtained were extremely puzzling in view of the total absence of carbon-containing substances, thought to be indispensable components of living organisms. All of the experiments yielded positive data, which in our earth-based laboratories would have been interpreted as unequivocal proof of biological activity and of the presence of life.
First, the Martian soil converted carbon dioxide to larger organic compounds to a slight extent. This ability of the soil was destroyed when the sample was heated prior to the addition of carbon dioxide. The Martian soil could also break down complex organic molecules to carbon dioxide, and pretreatment of the soil with heat destroyed this capacity of the soil as well. Third, when soil samples were moistened with water vapors, a rapid release of significant quantities of oxygen was noted. Along with this oxygen, carbon dioxide, carbon monoxide, nitrogen, and argon also evolved. Preheating the soil before the addition of water abolished the observed phenomena.
Why?
Reviewing these results, the preliminary scientific opinion was that in view of the absence of carbon-containing substances, all of these data can be best explained by purely chemical reasoning. It was postulated that extensive ultraviolet radiation of the sun interacted with the inorganic minerals of the Martian surface to create exotic and highly reactive substances that were responsible for the observed results of the biological experiments. But the first attempts to duplicate the Viking data in earth-based laboratories were unsuccessful. The first interim report by the project scientists concluded rather optimistically: "Thus, despite all hypotheses to the contrary, the distinct possibility remains that bio logical activity has been observed on Mars."
In July of 1977, Dr. Cyril Ponnamperuma's laboratory at the University of Maryland reported the results of experiments in which all of the positive results of Viking's biological experiments had been duplicated using metal peroxides or the iron oxide, hematite, exposed to ultraviolet radiation in the presence of carbon dioxide. (See Science 197:455- 457, 1977.) These findings provided the basis for the most reasonable explanation of all the observations.
The answer and its meaning
Late in 1977, project scientists of the National Aeronautics and Space Administration and of the Space Board of the National Academy of Sciences met to confer on the results of the Viking probes, with particular emphasis on the chemistry and biology of the Martian surface. After a thorough review of the data, the consensus was that Mars lacks every form of life, including micro organisms, and the search for life on that planet may be abandoned. Gerald Soffen of NASA's Langley Research Center was quoted: "I may have been prepared for the lack of life on Mars, but it never occurred to me that there would be no organic chemistry as well. Before the landings, most of the scientists at this meeting would have expected to find some sort of microorganisms in the Martian soil, but now I think just about everybody would have to say that, given the data we've received, it's highly unlikely that there is any life at all on Mars."
Through decades of continual reiteration, prominent scientists have persuaded the population in general to accept evolutionary theories as historical facts. Science and its practitioners have earned the confidence of the general public by their numerous novel discoveries and startling technological breakthroughs. This public confidence has enabled scientists to "sell" evolution successfully.
The theories of chemical evolution are said to be valid not only for earth but for any planet in the universe that possesses the needed raw materials and a continuous supply of energy from a nearby star. Mars admirably fits this category. Simulated Martian environment in the laboratory produced organic molecules with potential biological significance. Successful laboratory simulations of primordial synthesis of biologically important substances serve as the foundation for chemical evolutionary theories.
What the Viking results clearly show is that the laboratory synthesis of these substances in a simulated environment does not necessarily mean their actual accumulation on a planetary surface. In the case of Mars, highly reactive peroxides in its soil quickly degrade any organic molecule that may form in the Martian atmosphere. Prior to the Viking experiments, no one had seriously worried about the effect of unceasing ultra violet radiation on exposed inorganic mineral surfaces. Now the evidence points to the creation of a chemically highly reactive type of matter that can confound the best schemes of chemical evolution.
Was it worth a billion dollars to learn that there is neither life nor organic chemistry on Mars? It is not up to me to say. However, it was not at all a waste of money to find out that chemical evolution does not operate on our planetary neighbor. These results will cause more thinking people to realize that if chemical evolution is an invalid hypothesis for Mars, it is also invalid for earth. And they just may turn to the other alternative option for understanding our origins, the Biblical account of Special Creation.
