Faint Echoes, Distant Stars Read online

  Although many of the most respected astronomers of the nineteenth century gave serious thought to the possibilities of life on Mars, the association with science fiction toward the end of that century gave a bad odor to the search for life. Science fiction was considered to be lurid, semiliterate trash by the general public, and even worse by the conservative leaders of academia. Wells himself denigrated his own early work and moved on to more conventional fiction. He wrote twice as many “straight” novels as science fiction books, yet the world remembers The Time Machine and The War of the Worlds much better than Tono-Bungay or The World of William Clissold.

  THE FASCINATION OF MARS

  Wells did not pick Mars as the home of his invading aliens on a whim. Through much of the nineteenth century the world’s leading astronomers were very interested in Mars, and their fascination was passed on to the general public through books written about their observations—and their speculations on the possibilities of life on the red planet. Many believed that if there was one place in the wide and starry universe beyond our own Earth that might harbor life, even intelligent life, Mars would be that place.

  What made astronomers so interested in Mars?

  Mars has been known from time immemorial as one of the brightest lights in the night sky. Its obvious red tinge reminded people of blood and death, which led most cultures to name it after their god of war.

  Mars is the only planet whose surface can be seen in any detail from earthbound telescopes. Venus is slightly closer to Earth than Mars is, but Venus is perpetually covered from pole to pole by thick clouds; they make Venus glow beautifully in our sky but hide its surface from even the most powerful optical telescopes. The distant gas giant worlds of Jupiter and beyond are also covered with clouds and totally unlike our world. Mercury is barely discernable from Earth because it is so close to the Sun; far-off Pluto is a mere speck of light. Our own Moon, airless and waterless, is a barren ball of rock.

  Mars is a nearby neighbor, as planets go. About every twenty-six months the red planet comes to within 56 million kilometers of Earth. Only Venus gets closer, about 40 million kilometers. Today’s spacecraft make the journey to Mars in nine months or less; with only a modest extension of existing technology, humans could explore Mars in person.

  AN EARTH-LIKE WORLD?

  Mars is the most Earth-like planet in the solar system. Its axial tilt is similar to Earth’s. It spins about its axis in just a little more than twenty-four hours. It has obvious polar caps, which melt in the summer and form again in the winter. Mars has seasons, and nineteenth-century astronomers saw that when the polar cap melted in the spring, that hemisphere underwent a “wave of darkening,” as if foliage were sprouting as water from the pole made its way toward the equator.

  Does life exist there?

  In 1877, the Italian astronomer Giovanni Schiaparelli reported seeing straight-line markings on the rust-red face of Mars. He called them canale, meaning “channels.” Other astronomers also saw such markings across the ruddy face of Mars. However, in France, Eugene M. Antoniadi, using one of the biggest telescopes available at the time, saw only irregular dark blotches and spots that might look like straight lines in the smaller instruments that Schiaparelli and others were using. Yet despite Antoniadi’s skepticism, many astronomers who peered at the red planet reported seeing straight lines running across the ruddy disk of Mars.

  Recognize their difficulties. The big telescope that Antoniadi used was an eighty-four-centimeter refractor, puny in comparison to the five-, eight-, and ten-meter “light buckets” of modern observatories. Never closer than 56 million kilometers, the disk of Mars averages only a hundredth of the diameter of the full Moon. In those modest telescopes of the nineteenth century, Mars was a faint reddish disk that faded in and out of focus. Eyestrain was a persistent problem, because astronomers had not yet started to use cameras to record what they saw; they peered through their telescopes for long hours and drew sketches of what they observed. Indeed, when they began to photograph Mars, their pictures failed to show canals.15

  INTELLIGENT MARTIANS?

  Although Schiaparelli and most other astronomers interpreted what they saw quite conservatively, they could not overlook the possibility that those straight lines criss-crossing the face of Mars were indeed the work of intelligent engineers. In those days before wireless radio, some suggested that we should attempt to communicate with the hypothetical Martians. One scheme was to plant giant stands of trees in the shapes of geometrical figures, such as triangles and squares, then see if the Martians duplicated the feat on their world.

  Enter Percival Lowell.

  Born to a wealthy Boston family in 1855, Lowell attended Harvard and was described as a brilliant student of mathematics. Although astronomy had been a boyhood passion of his, from his Harvard graduation in 1874 until 1893 he occupied himself with the family business and traveling. He wrote books about Asia that were very well received by the reading public and made him something of a hero in Japan.

  In 1893, inspired by Schiaparelli’s description of the canale on Mars, Lowell set up an observatory in the clear mountain air of Flagstaff, Arizona. He spent the rest of his life studying Mars and writing popular books about what he saw.

  Lowell saw CANALS on Mars. Lots of them. He was not content with the conservative attitudes of Schiaparelli and most of the other astronomers who, at best, claimed nothing more than observing straight-line features on the red planet. Lowell created an explanation for those straight lines. He postulated that Mars was a dying world, its supply of water and air slowly leaking away into space. Intelligent Martian engineers had built the canal system, Lowell believed, to carry water from the polar caps to their cities in the encroaching global desert.

  “That Mars is inhabited by beings of one sort or other,” he wrote, “is as certain as it is uncertain what those beings may be.”

  Most astronomers pointed out that Mars was too cold and dry for liquid water to exist on its surface. They even claimed that the polar caps were not water ice at all, but frozen carbon dioxide: dry ice.

  Still Lowell and his staff doggedly produced extensive maps of Martian canal systems for several decades. When skeptics pointed out that canals would be much too thin to be discerned over the distance between the two planets, Lowell and his followers ingeniously countered that what the telescopes detected was not the canals themselves, but the bands of vegetation—farmlands—on either side of the canals.

  Faced with the contention that water would quickly evaporate in the dry, thin Martian atmosphere, the “canalists” proposed that the Martians were clever enough to cover the water’s surface with a slick of oil or perhaps even build roofs over their canals.

  It was Lowell’s vision of Mars that inspired H. G. Wells’ War of the Worlds. When Wells published his novel in 1898, it was not beyond reason to believe (thanks to Lowell) that Mars might possibly be inhabited by creatures of high intelligence, mighty engineers who were desperately striving to save their dying world.

  The success of Wells’ novel inspired many other writers to produce stories about Mars and Martians. Most of them were dreadful, featuring “bug-eyed monsters” (BEMs), and bore scant relation to what was known of Mars. The subject of Martian life acquired a distinctly unsavory odor in the halls of academia. Astronomer James Keeler, speaking at the 1897 dedication of the Yerkes Observatory in Wisconsin, said sternly:

  “It is to be regretted that the habitability of the planets, a subject of which astronomers profess to know little, has been a chosen theme for exploitation by the romancer . . . The result of his ingenuity is that fact and fiction become inextricably tangled in the mind of the layman . . .”

  The “romancer” that Keeler objected to was probably not Wells, whose novel would not be published until the following year, but Lowell, who was turning out extremely popular books about his views of Mars and Martians. Lowell’s picture of a dying Mars peopled by brave and industrious canal-builders caught the public’s imagin
ation, much to the discomfort of most academic astronomers. It was Lowell’s version of Mars that inspired Edgar Rice Burroughs, the creator of Tarzan, to start a long series of lushly romantic novels set on Mars, beginning with A Princess of Mars in 1917. Burroughs’ fiction is not well regarded today, but his “Martian” novels inspired a youngster named Carl Sagan to dedicate his career to searching for life beyond Earth.

  THE “GIGGLE FACTOR”

  Under the pressure of disdain from the leaders of the field, many astronomers turned away from studies of Mars and the question of intelligent alien life. The entire matter of searching for extraterrestrial life became burdened with a heavy “giggle factor.” Department heads in schools of astronomy branded the very thought of alien life as nonsense, in large part because it had become associated with that dreadful tripe called science fiction.

  Moreover, new and bigger telescopes were coming online, and they gave astronomers a new capability for studying the stars, far beyond our solar system. As the twentieth century progressed, the forefront of astronomical research dealt with the stars, not the planets, and the new realization that the so-called “spiral nebulae” were not clouds of gas within the Milky Way but independent galaxies millions of light-years beyond the Milky Way, each of them containing hundreds of billions of stars. The big questions in astronomy during the first half of the twentieth century dealt with cosmology—the study of the nature and origins of the entire universe. Planetary astronomy was largely neglected and became a backwater of astronomical research. Discussions of extraterrestrial life were couched in the most conservative terms possible, when they were countenanced at all.

  Yet Mars was still popular in the public’s imagination. In 1900, a French widow, Clara Goguet Guzman, established a foundation to award a prize of 100,000 francs to the first person to make contact with creatures on another planet and receive a response. A board of scientists was enrolled to administer the award, which was named after Mme. Guzman’s son, Pierre. It became known as the Guzman Prize. The board decided to rule Mars out of contention for the prize money, because Mars was too easy! They expected communications to be established with Martians in the near future.

  In 1924, astronomer David Todd of Amherst College organized a nationwide program among amateur radio operators to listen for possible signals from Mars during the red planet’s close approach that year. He even talked the U.S. Army and Navy, possessors of the most powerful radio equipment in America, into joining the hunt. Todd asked the fledgling commercial radio stations across the nation to go silent during the “listen-in,” so that faint signals from Mars might be detected. Few complied with his request; even then, commercial radio stations were more interested in commerce than science. Nothing was heard by the thousands of radio “hams” and military radio operators except interference from terrestrial radio broadcasts.

  A few astronomers persisted in studying the planets. As their instruments improved, they found that Mars was even colder and drier than they had previously assumed and its atmosphere even thinner. Still, there were seasonal changes of color on Mars. Could they be caused by life, some form of vegetation blooming as precious water seeped down from the poles in the Martian springtime? If any forms of life could survive in such a planet-wide freezing desert, it was thought that they could only be simple, rugged organisms such as single-celled algae or “primitive” lichens, which on Earth are symbiotic combinations of algae and fungi. While some stubborn souls maintained that only highly adapted organisms could survive in the bitter Martian environment, the “algae and lichen” argument held sway. No one but science fiction enthusiasts still talked about canals on Mars, and even that was mostly wishful thinking.

  As late as 1955 the highly respected Dutch-American astronomer Gerard Kuiper (1905–1973) said, “The hypothesis of plant life . . . appears still the most satisfactory explanation of the various shades of dark markings and their complex seasonal . . . changes.”

  It was none other than the young Carl Sagan who showed in the early 1960s that the seasonal color changes across the face of Mars might be caused by dust storms, not springtime blooming. Even the most optimistic astronomers concluded that if Mars is an abode of life, the “Martians” must be simple plant life, nothing more.

  Yet all this would change with the advent of the space age.

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  Exploring Mars

  From this point on, there is life on Mars—an extension of our sensibilities. Man is reaching across space and reaching Mars. Our life is on Mars now.

  —Ray Bradbury

  BRADBURY, author of the science fiction classic The Martian Chronicles, was speaking excitedly at the moment that NASA’s Viking 1 lander touched down on Mars, July 20, 1976.

  Not everyone was so enthusiastic.

  Many scientists had complained bitterly about NASA’s Apollo project. They asserted that the $20 billion spent to send a dozen astronauts to the Moon’s surface would have been put to much better use in funding science on Earth. Moreover, they contended, Apollo was basically an engineering program aimed at planting “flags and footprints” on the Moon without doing much science. Of the twelve astronauts who walked on the lunar surface, only one was a scientist: geologist Harrison Schmitt of Apollo 17, the last Moon mission. The other eleven were test pilots and fighter jocks.

  The scientists were being short-sighted. Their basic argument was that they wished the government would spend that kind of money on their research projects. What they overlooked was that Apollo created the technology to reach any planet in the solar system and the technical/administrative organization to use that technology creatively.

  Much of this capability resides at the Jet Propulsion Laboratory in Pasadena. Founded during World War II, JPL became a part of NASA when the space agency was created in 1958. JPL is administered by the California Institute of Technology, and it is responsible for most of NASA’s scientific planetary missions.

  Sagan and the leaders at JPL, together with a few others, understood NASA’s capability, and as the Apollo program caught the public’s imagination, they urged decision-makers in Congress and the White House to use spacecraft to explore the solar system. The politicians, who had by then killed further Apollo missions to the Moon, demanded something “sexy” to show to the voters as an excuse for spending more money on space.

  Sagan and “the JPL crowd” suggested looking for life on other planets. What could be more exciting than finding life on another world? And what world would be more logical to search than nearby beckoning Mars?

  At that time, the Cold War was still very bitter, with American involvement in Vietnam and Soviet pressure in Berlin and elsewhere. Success in space was still valuable propaganda in the global battle for prestige. The Soviet Union launched a long series of spacecraft at Mars and Venus. Their Venera 7 was the first spacecraft to land on another planet—Venus, in 1970—and transmit pictures from its surface.

  DEAD MARS

  Partly to compete against the Russians and partly because Sagan and others held out the allure of finding life, Washington agreed to fund several robotic spacecraft missions to Mars in the 1960s and 1970s.

  That decision almost killed the scientific exploration of the solar system.

  The first space probe to send close-up imagery of the Martian surface was NASA’s Mariner 4, which flew to within 9,780 kilometers of the red planet on July 15, 1965. The twenty-two photographic images sent by Mariner 4 ended forever any speculations about Martian canals and convinced most observers that Mars could not possibly be an abode for any kind of life. Mariner 4’s imagery showed a stark dry desert, pockmarked with meteor craters.

  In 1969, Mariner 6 and 7 sent back more disheartening images, and in 1971, Mariner 9 became the first spacecraft to successfully establish itself in orbit around another planet.

  No canals. No Martians. Not the slightest sign of life.

  In a sense, the Martian canals had indeed been created by intelligent minds: the minds of Lowell and other hum
an observers who believed they saw canals. With the telescopes available in their day, those astronomers were peering out at the far edge of observability. They saw a faint, ruddy disk shimmering in and out of focus because of the turbulence in Earth’s atmosphere. Their minds connected faint blobs of markings into straight lines—partially an optical illusion, partially a classic case of seeing what you dearly want to see.

  When spacecraft began observing Mars from close-up, the canals disappeared. They were never there. The pitiless cameras aboard a succession of NASA Mariner spacecraft showed no canals, no cities, no Martians, not even algae or lichen, only an utterly barren, sandy waste of desert—and lots of craters. Mars looked more like the battered sterile face of the Moon than a planet that could spawn invading aliens.

  A SPECTACULAR PLANET

  Yet what the spacecraft pictures were showing was exciting in its own way. For the first time, we were seeing the true face of another planet, and although it may not be the world Lowell, Wells, Burroughs, and Bradbury envisioned, it was a fascinating new world nonetheless.

  Mars is a truly spectacular world. The tallest mountain in the solar system is there, Olympus Mons, three times taller than Everest. It is a huge volcano that seems to be silent now, although its mighty lava flows have covered an area the size of Washington state. Olympus Mons is part of a group of giant shield volcanoes that have risen on an uplifted section of Mars called the Tharsis Bulge. What caused the bulge and gave rise to such massive volcanoes? Mars seems too small and its core too cold to have active plate tectonics. This leads geologists to surmise that the volcanoes must have formed very early in Mars’ history, when its interior was still molten. But there are other possibilities.