Extraterrestrial Civilizations (9 page)

Lowell’s role in making advanced Martian life popular was outpaced, however, by the English science fiction writer, H. G. Wells.

In 1897, Wells published a novel,
War of the Worlds
, in serial form in a magazine, and the next year it appeared in book form. It combined the view of Mars as presented by Lowell with the situation as it had existed on Earth over the preceding twenty years.

In those decades, the European powers—chiefly Great Britain and France, but including also Spain, Portugal, Germany, Italy, and
Belgium—had been carving up Africa. Each nation established colonies with virtually no regard for the wishes of the people already living there. Since the Africans were dark skinned and had cultures that were not European, the Europeans considered them inferior, primitive, and barbarous, and felt they had no rights to their own territory.

It occurred to Wells that if the Martians were as far advanced scientifically over Europeans as Europeans were over Africans, the Martians might well treat Europeans as Europeans treated Africans.
War of the Worlds
was the first tale of interplanetary warfare involving Earth.

Until then, tales of visitors to Earth from outer space had pictured those visitors as peaceful observers. In Wells’s novel, however, the outsiders came with weapons. Fleeing a Mars on which they could barely keep alive, they arrived at lush, watery Earth and prepared to take over the planet to make a new home for themselves. Earth people were merely animals to them, creatures whom they could destroy and devour. Nor could human beings defeat the Martians or even seriously interfere with them, any more than the Africans could deal with the European armed forces. Though the Martians were defeated in the end, it was not by human beings, but by Earthly decay bacteria, which the Martians’ bodies were not equipped to resist.

It proved a popular novel and set off a wave of imitations, so that for the next half-century human beings took it for granted that any invasion of extraterrestrial intelligence would lead to the extermination of humanity.

On October 30, 1938, for instance, nearly forty years after
War of the Worlds
was published, Orson Welles (1915–), only twenty-three years old at the time, produced a radio dramatization of the story. He chose to bring the story up to date, and had the Martians land in New Jersey rather than in Great Britain. He told the events in as realistic a fashion as possible, with authentic-sounding news bulletins, eye-witness reports, and so on.

Anyone who had turned the program on at the start would have been informed that it was fiction, but some weren’t listening closely enough and others turned it on after the start and were transfixed at the events that were apparently taking place—especially those who were near the sites of the reported landings.

A surprising number of people did not pause to question whether it was at all likely that there was an invasion of Martians, or whether there were even Martians at all. They took it for granted that Martians existed and had arrived to conquer Earth and were succeeding. Hundreds got into their automobiles and fled in terror. Like the Moon Hoax of just a century before, it was a remarkable example of how ready people were to accept the notion of extraterrestrial intelligence.

Though Lowell and his theories concerning the Martian canals were successful with the general public, professional astronomers were extremely doubtful. At least the large majority were.

A number insisted that though they looked at Mars carefully, they never saw any canals, and they were not soothed by Lowell’s lofty assurance that their eyes and telescopes just weren’t good enough. The American astronomer Asaph Hall (1829–1907), whose eyes had been good enough in 1877 to discover the tiny Martian satellites, never saw a canal.

One American astronomer, Edward Emerson Barnard (1857–1923), was a particularly keen observer. In fact, he is often cited as the astronomer with the sharpest eyes on record. In 1892, he discovered a small fifth satellite of Jupiter, one that was so small, and so close to the brightness of Jupiter itself, that to see it required eyes of almost superhuman keenness; yet Barnard insisted that no matter how carefully he observed Mars, he could never see any canals. He said flatly that he thought it was all an optical illusion; that small, irregular patches of darkness were made into straight lines by eyes straining to see objects at the very edge of vision.

This notion was taken up by others. An English astronomer, Edward Walter Maunder (1851–1928), even put it to the test in 1913. He set up circles within which he put smudgy irregular spots and then placed schoolchildren at distances from which they could just barely see what was inside the circles. He asked them to draw what they saw, and they drew straight lines such as those Schiaparelli had drawn of the Martian canals.

Meanwhile, astronomers continued to study the habitability of Mars. As the twentieth century advanced, instruments were devised that could detect and measure tiny quantities of heat. If these heat detectors were placed at the focus of a telescope and the light from
Mars were allowed to fall upon it, the temperature of Mars could be deduced.

This was first done in 1926 by two American astronomers, William Weber Coblentz (1873–1962) and Carl Otto Lampland (1873–1951). From such measurements, it seemed that at the Martian equator the temperature would rise above the melting point of ice at times. In fact, it was even possible for the equatorial temperatures to rise as high as 25° C (77° F) on rare occasions.

The temperature dropped sharply during the night, however. There was no way of following the temperature at night, for the night side of Mars was always on the side away from Earth. However, the temperature of the early morning could be taken at the western edge of the Martian globe where the surface of the planet was just emerging from night and into the dawn. After twelve and a quarter hours of dark, the temperature could be as low as –100° C (–150° F).

In short, it looked as though the temperature of Mars was too low for water to exist as anything but ice, except in a narrow region around the equator and for brief times around midday. Elsewhere, the climate on Mars was colder than that in Antarctica.

Worse yet, the great difference between dawn temperatures and noon temperatures meant that the Martian atmosphere was probably thinner than had been thought till then. An atmosphere acts as a blanket, absorbing and transferring heat, and the thinner it is the more rapidly temperatures go up and down.

What’s worse is that a thin atmosphere does not absorb much of the energetic radiation of the Sun. On Earth, the relatively thick atmosphere acts as an efficient blanket absorbing the energetic radiation that bombards our planet from the Sun and elsewhere.

All these energetic radiations would be fatal to unprotected life if they fell upon Earth’s surface in full strength. Mars is farther from the Sun than we are and it receives a smaller concentration of ultraviolet light, for instance. However, that smaller concentration reaches the Martian surface in far greater quantities, it would appear, than it reaches the terrestrial surface.

By the 1940s, it became possible to analyze the infrared radiation from Mars to analyze the content of its atmosphere. This was done in 1947 by the Dutch-American astronomer Gerard Peter Kuiper (1905–1973). He found that what little there was of the
Martian atmosphere was almost entirely carbon dioxide. There was very little water vapor and apparently no oxygen at all.

Considering the frigidity of Mars, some astronomers began to wonder if there was any water on Mars at all. Might the ice caps not be frozen water, but frozen carbon dioxide instead?

Taking all things into consideration—a thin atmosphere of carbon dioxide, ultraviolet light bombarding the Martian surface, temperatures of deep frigidity—it seemed unlikely that the kind of complex life forms one would expect to have developed intelligence would have evolved on Mars.

The feeling grew that if the canals existed at all, they were natural phenomena, not the product of a race of advanced engineers.

But then, if not intelligent life, what about primitive life? On Earth, there are bacteria that can live on chemicals poisonous to other forms of life. There are lichens that can grow on bare rock, and on mountaintops where the air is so thin and the temperature is so low that one might almost imagine one’s self to be on Mars.

Beginning in 1957, experiments were conducted to see if any simple life forms that were adapted to severe conditions on Earth might survive in an environment that, as far as possible, duplicated what was then known of the Martian environment. Over and over again it was shown that some life forms would survive.

Perhaps, in that case, we ought not abandon all hope of complex life forms either. After all, life on Earth has evolved to fit the terrestrial environment. To us, therefore, conditions on Earth seem pleasant, and conditions that are considerably different from those on Earth seem unpleasant. On Mars, however, life forms would have evolved to suit the conditions there, and it would then be those conditions that would seem pleasant to them.

The question appeared moot right into the 1960s.

In the 1960s, rocket-powered probes were being launched that were intended to pass near the planet and send back information (like the ones I have already mentioned in connection with Mercury and Venus).

On November 28, 1964, the first successful Mars probe,
Mariner 4
, was launched. As
Mariner 4
passed Mars it took a series of twenty photographs that were turned into radio signals beamed back to Earth, where they were turned into photographs again.

What did they show? Canals? Any signs of a high civilization or, at least, of life?

What the photographs showed turned out to be completely unexpected, for as they were received, astronomers saw what were clearly craters—craters that looked very much like those on the Moon.

The craters, at least as they showed up on the
Mariner 4
pictures, seemed so many and so sharp that the natural conclusion was that there had been very little erosion. That seemed to mean not only thin air, but very little life activity. The craters shown in the photographs of
Mariner 4
seemed to be the mark of a dead world.

Mariner 4
was designed to pass behind Mars (as viewed from Earth) after its flyby, so that its radio signals would eventually pass through the Martian atmosphere on their way to Earth. From the changes in the signals, astronomers could deduce the density of the Martian atmosphere.

It turned out that the Martian atmosphere was even thinner than the lowest estimates. It was less than 1/100 as dense as Earth’s atmosphere. The air pressure at the surface of Mars is about equal to that of Earth’s atmosphere at a height of 32 kilometers (19 miles) above the Earth’s surface. This was another blow to the possibility of advanced life on Mars.

In 1969, two more rocket probes,
Mariner 6
and
Mariner 7
, were sent past Mars. They had better cameras and instruments, and took more photographs. The new and much better photographs showed that there was no mistake about the craters. The Martian surface was riddled with them—as thickly, in places, as the Moon.

The new probes, however, showed that Mars was not entirely like the Moon. There were regions in the photographs in which the Martian surface seemed flat and featureless and others where the surface seemed jumbled and broken in a way that was not characteristic of either Moon or Earth. There were still no signs of canals.

On May 30, 1971,
Mariner 9
was launched and sent on its way to Mars. This probe was not merely going to pass by Mars, it was to go into orbit about it. On November 13, 1971, it went into orbit. Mars
was at that time in the midst of a planet-wide dust storm and nothing could be seen, but
Mariner 9
waited. In December, 1971, the dust storm finally settled down and
Mariner 9
got to work taking photographs of Mars. The entire planet was mapped in detail.

The first thing that was settled, once and for all, was that there were no canals on Mars. Lowell was wrong after all. What he had seen was an optical illusion.

Nor were the dark areas either water or vegetation. Mars seemed all desert, but here and there one found dark streaks that usually started from some small crater or other elevation. They seemed to be composed of dust particles blown by the wind and tended to collect where an elevation broke the force of the wind, on the side of the elevation away from the wind.

There were occasional light streaks, too, the difference between the two resting perhaps in the size of the particles. The possibility that the dark and light areas were differences in dust markings and that the dark areas expanded in the spring because of seasonal wind changes had been suggested a few years earlier by the American astronomer Carl Sagan (1935–).
Mariner 9
proved him to be completely correct.

Only one of the hemispheres of Mars was cratered and Moonlike; the other was marked by giant volcanoes and giant canyons, and seemed geologically alive.

One feature of the Martian surface roused considerable curiosity. These were markings that wiggled their way across the Martian surface like rivers and that had branches that looked for all the world like tributaries. Then, too, both polar ice caps seemed to exist in layers. At the edge, where they are melting, they looked just like a slanted stack of thin poker chips.

It is possible to suppose that Mars’s history is one of weather cycles. It may now be in a frigid cycle, with most of the water frozen in the ice caps and in the soil. In the past, and possibly again in the future, it may be in a mild cycle, in which the ice caps melt, releasing both water and carbon dioxide, so that the atmosphere becomes thicker and the rivers grow full.

In that case, even if there is no apparent life on Mars now there may have been in the past, and there may again be in the future. As for the present, life forms could be hibernating in the frozen soil, in the form of spores.