Friday, August 6, 2010

Martian Life: Canals on Mars Evidence of Past Glories

Prof. Percival Lowell is certain that the canals on Mars are artificial. And nobody can contradict him. —Clipping from unidentified newspaper (summer 1905)

Canals on Mars
On May 19, 1910, less than two months before his death, Schiaparelli publicly stated that natural forces could account for the dark lines seen on Mars. However, he went on to suggest that someone assemble all evidence related to the existence of intelligent life on the planet. In the concluding paragraphs of his final communication on Mars, Schiaparelli mentions his admiration for the work of Percival Lowell. This praise for Lowell raises doubts about Schiaparelli’s acceptance of a natural explanation of the canali. Lowell was an outspoken defender of canals built by Martians throughout his scientific career (1894– 1916). Percival Lowell (1855– 1916) was the most powerful champion within the scientific community for the idea of intelligent Martian life. His claim that the Martian landscape included a global irrigation system influenced the conception of Mars held by scientists, government officials, and the general public well into the second half of the twentieth century. Unlike Schiaparelli, Lowell wrote popular books and magazine articles and lectured widely on Martians as canal builders. Lowell was an energetic and effective publicist for his views on Martian life. Some writers have called Lowell a newcomer to astronomy, an outsider, and even an amateur. When Lowell began his scientific career, entrance into the profession did not require an advanced degree in astronomy. A number of distinguished early twentieth-century astronomers, including directors of major observatories, never received advanced training in astronomy. Lowell’s credentials as an astronomer were not unusual for his times. Lowell studied mathematics at Harvard University under America’s premier mathematician, Benjamin Peirce. Peirce fully expected his brilliant student to succeed him as a professor of mathematics. Lowell had different plans for the future. After spending a year abroad, and the next six years attending to the business holdings of his illustrious and wealthy family, Lowell left America to study the Far East. In 1882 Lowell had attended a lecture on Japanese culture by zoologist Edward S. Morse. Morse’s lecture inspired Lowell to travel to Asiatic countries recently opened to the West. The dark regions of the planet observed by astronomers were areas of vegetation, not bodies of water. The melting of the polar ice caps during the warm season freed water to flow through the canal system. The flowing water irrigated the desiccated planet and brought life to its vegetation. Lowell’s theory, completed after a short stay at Flagstaff, changed little over the next twenty years. In describing the orderly arrangement of the Martian canals, Lowell compared them to trigonometric figures. Lowell’s maps of the canals are simpler and more geometrical than Schiaparelli’s. There are two explanations for Lowell’s schematic maps. First, Lowell studied Mars using Schiaparelli’s maps as his guide. Second, according to Carl Sagan, Lowell was a poor draftsman who drew polygonal blocks linked by many straight lines. Pickering and Douglass were no better at rendering details of the Martian surface than Lowell.

Ancient Martian City?
The unique physical conditions of the planet, Lowell declared, explained the social behavior and technology of the intelligent creatures who lived there. Lowell claimed that because Mars was smaller than the Earth, it evolved faster. Mars continued on its rapid evolutionary path and soon reached the final stages of planetary development. Lowell believed that Mars was older than the Earth. All planets, Lowell argued, become drier as they age. At one time, the Earth had much more water than land. On Mars, land had largely replaced water, leaving the planet covered with vast desert regions of a reddish-ochre color. This color reminded Lowell of the Sahara region of northern Africa or the Painted Desert of Arizona. Mars was dry but not without water. Lowell drew attention to Martian polar caps that melted during the warm seasons. As the polar caps retreated, a deep blue band appeared around the poles. This band was ice that melted with the rising temperature of the Martian spring and summer. Lowell dismissed the hypothesis that the polar caps were largely frozen carbon dioxide, not snow and ice. A desert planet with water frozen in polar ice caps is an unlikely habitat for life. However, Lowell assured us that Mars had enough water to sustain life. It also had an adequate supply of air, another crucial ingredient of life. Lowell’s telescopic study of the disk of Mars convinced him, if not other astronomers, that Mars had an atmosphere. Water circulated throughout the atmosphere in a vaporous form and condensed at the poles of the planet. The freezing and melting of water at the polar caps convinced Lowell that the average temperature of Mars was comparable to the Earth’s, if not higher. Hence, Martian polar caps shrink back far more drastically during the warm seasons than do the ice caps at the Earth’s poles. The existence of water and air on Mars, along with its mild climate, were essential to Lowell’s picture of the planet as a place of constant change. It was not static like the airless, waterless, and lifeless Moon. Lowell first described the physical characteristics of Mars. Then he was ready to introduce life there. The Martian climate, smooth terrain, and adequate supply of water and air indicated life could thrive on the planet. If astronomers properly examined Mars through their telescopes, evidence of life would emerge.

Lowell claimed that the dark, bluish green regions of Mars turn to shades of gray and brown seasonally. The dark areas are plants that flourished with warmth and moisture and faded when the frosts of the Martian autumn arrived. The changing colors of Martian vegetation reminded Lowell of American forests seen from a distance.

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