TCS Daily

Close Encounter

By Sallie Baliunas - August 15, 2003 12:00 AM

This year Mars and the earth will be extraordinarily close -- on August 27 the earth will sweep closer than 35 million miles to Mars. It's enough to give earthlings Mars Fever.


Not since the deep ice of the last glaciation swept across much of cold northern Europe and North America, not since the wooly rhinoceros ran through southern France, not since modern man's close relative Neandertalensis dominated the caves of western Europe, not for more than 59,000 years has Mars been so near the earth.


Mars appears now and for the next several months in the southern night sky as a reddish star, brighter than the other stars. Mars gets its notable hue from iron oxides in its surface soils. We can only guess what myths our forebears made to explain the bright red-orange light some sixty millennia ago. Our modern word for the fiery red planet comes from Roman mythology of the war-god Mars.


Modern man, too, has Mars myths, inspired by telescope views. Galileo and his contemporaries gazed at Mars with early, small-aperture telescopes, but the planet is small - it is one-tenth the mass of the earth and around one-half the diameter - revealing little detail, even at closest approach to the earth. However, as telescope light-gathering power and magnification increased, a new strain of Mars Fever erupted in the mid-19th century


While mapping the Martian surface in 1858, Father Angelo Secchi named one feature the Atlantic Canale. He intended the Italian word canale to mean channel. In 1869, with the completion of the Suez Canal the public became familiar with the idea of constructing great artificial waterways. In 1877 Giovanni Schiaparelli borrowed Fr. Sechhi's term and mapped the canali, or channels, seen emanating from the darkish areas on the surface of Mars. During the close approach of 1879, Schiaparelli noticed something new: closely-spaced parallel canali, which surely had to be artificial. All such straight-line markings on Mars are illusions, but the mistranslation of canali from Italian to canals in English triggered an epidemic of Mars Fever.


Speculation about the canal builders spread wildly. The public wished to believe that advanced civilizations existed on Mars. Their ancient oceans gone, their planet dying, Martians had built elaborate canal systems to survive. Brackish areas like Syrtis Major, whose edges changed over the years, were thought of as seasonal plant growth and retreat irrigated by the canals, instead of the shifting sands they are.


Camille Flammarion's popular La Planète Mars et ses Conditions d'Habitabilité was published in 1892 and read by many. Plans were devised for signaling the Martians, despite what was sure to be a formidable impediment in translating between Martian and English.


A re-infection of Mars Fever happened in 1894 when charismatic Percival Lowell built the eponymous Observatory in northern Arizona. Lowell sensationalized the myth of artificial canals, declaring that they changed with Martian seasons on the arid plains, as if they were, he wrote, "constructed for the express purpose of fertilizing the oases." His 1895 book Mars captivated many who wished to believe in ancient Martians, for which there was absolutely no evidence. Lowell's 1906 Mars and Its Canals maintained public excitement so that in 1907 the Wall Street Journal asserted that "astronomical observations" proved "that conscious, intelligent human life exists upon the planet Mars." In 1911 The New York Times ran the story, "Martians Build Two Immense Canals in Two Years." Edgar Rice Burroughs' 11-book science fiction series began in 1911 with Princess of Mars.


But other astronomers could neither see nor photograph the chimerical canali. E. E. Barnard at Lick Observatory, E. W. Maunder in England, Charles A. Young at Princeton, Asaph Hall at the U.S. Naval Observatory and G. E. Hale, founder of Mount Wilson Observatory, were skeptical throughout the popular frenzy. Hale, using the largest reflecting telescope in the world at one of the finest sites for image stability, described in 1909 that the Martian surface markings mistaken for straight lines "were vague and diffuse and by no means narrow and sharp," and were "made up of interlacing and curved filaments." The wisps are natural surface features.


As telescopes and instrumentation improved, the canals evaporated. The air pressure on Mars is less than one percent that of the earth's at sea level, and the air is extremely arid. But NASA spacecraft images show signs of past rivers, volcanic activity and a once-thicker atmosphere. Water yet exists, frozen in the polar caps and perhaps in subsurface reservoirs. Given water and a thicker atmosphere, would ancient Mars have incubated primitive life? Possibly.


Find a telescope in the next few months and gaze at Mars' polar caps and changing surface. While sweeping over the sands of Mars, remember that just a century ago Mars Fever led to the popular myth of an old alien civilization that excavated massive canals on drying Mars. But Mars Fever still lingers, and may return as the latest scientific chapter in the saga of the search for life on Mars is written by new research conducted from spacecraft. As you watch the Martian desert glimmer and imagine the songs of the shifting sand dunes, you might hear a soft sigh in your mind, "John Carter of Earth, Dejah Thoris of Mars awaits."


Recommended reading: The Planet Mars: A History of Observation and Discovery, William Sheehan, University of Arizona Press, 1996


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