Tuesday, September 27, 2011

Is there Life or Water on Mars?

Posted by Darin Hayton on 09/27 at 10:42 PM

Mars and its possible water seem to be a perennial topic for astronomers since 1877 when the Italian astronomer Giovanni Schiaparelli first noticed “canali”—a network of straight lines across the surface of the planet. Although Schiaparelli did not infer from these that the planet was inhabited, for the next thirty years his canali sparked the imagination of numerous astronomers and popularizers. Even today astronomers continue to argue about whether or not the evidence indicates flowing water on the Mars. Most recently, in August and then September two separate articles appeared arguing for and against water on Mars.1

In the early 1890s Percival Lowell was looking around for a new hobby to occupy his time and wealth. He had spent much of the previous decade traveling around and writing about the far east, especially Japan. After reading Camille Flammarion’s La planète mars, Lowell decided to dedicate his fortune to studying the planet in an effort to demonstrate that it was inhabited by intelligent life. In 1894 he established his astronomy in Flagstaff, AZ just in time to study the planet during its next opposition. He immediately wrote a popular book on Mars, Mars (Boston: Houghton, Mifflin and Company, 1896) in which he claimed that the canal structures he saw on Mars were evidence of intelligent life. Further, he claimed that the planet was slowly dying, and that these canals were efforts by the Martians to irrigate their planet during the summer months, when the polar icecaps melted.

Two years later Lowell published the first book-length scientific study of the canals of Mars, The Annals of the Lowell Observatory, vol. 1 (1898).

Lowell’s Annals of the Lowell Observatory, in which he presented the evidence for the canals on Mars (Source: Author’s collection)

Here he surveyed the phenomena—seasonal variations in the polar icecaps, dark regions that grew as the icecaps shrank, the long lines that seemed to extend great distances across the planet, oases that formed at the conjunctions of canals—and concluded unambiguously: “Upon the above results of the observations is based the deduction I have here put forward,— (1) of the general habitability of the planet; (2) of its actual habitation at the present moment by some form of local intelligence.”

Lowell’s color drawings showing the Martian seas as they expand during the summer season (Source: Author’s collection)

Lowell went on to establish himself as the authority on Mars, publishing numerous scientific articles as well as two more popular books, Mars and Its Canals (New York: The Macmillan Company, 1906) and Mars as the Abode of Life (New York: The Macmillan Company, 1910). He continued his program of observation. Seemingly with each new observation he found yet another canal or oasis. He dedicated subsequent volumes of the Annals of the Lowell Observatory to his observations, mapping the canals across the entire globe, more than 700 canals in all.

A later map of Mars showing some of the the many canals Lowell discovered (Source: Author’s collection)

His conviction that there was intelligent life on Mars never wavered. Between 1906 and his death in 1916 articles on Mars appeared regularly in the popular press. Although the press rarely missed an opportunity to celebrate Lowell’s accomplishments, it also reported on some of the controversy: Harvard’s Edward Pickering thought the canal-like structures were naturally occurring fissures resulting from the planet’s shrinking; A.S. Eddington, Assistant to the Astronomer Royal agreed with Pickering. The director of the Lick Observatory, W. M. Campbell published a paper in Science in 1909 in which he argued that spectral analysis of the Martian atmosphere revealed no water vapor—Lowell rejected this evidence.

In 1907 the British naturalist Alfred Russel Wallace joined the fray, attacking Lowell and his claims in a short book: Is Mars Habitable? A Critical Examination of Professor Percival Lowell’s book “Mars and its canals,” With An Alternative Explanation (London: Macmillan and Co., 1907). Wallace analyzed the Martian atmosphere and the climate, especially the temperature, and consulted experts. In the end, he found Lowell’s studies flawed. Wallace had recently published his essay Man’s Place in the Universe, an anthropocentric philosophical reflection arguing that only on earth was there intelligent life. His anthropomorphic philosophy prompted him to reject Lowell’s theory.

Percival Lowell

Although by 1913 the tide seemed to be turning against Lowell’s Martians and their dying planet, by sheer force of will and economic resources, Lowell was able to keep the question of Martians a viable scientific and popular problem until his death in 1916. After his death, the questions shifted from intelligent, human-like Martians to more general speculation about animal life on Mars. Shortly after the discovery of Pluto—another of Lowell’s hobbies—Popular Science published a short article speculating on the type of creature that might inhabit Mars: “Do Beavers Rule on Mars?”

An article in Popular Science speculates that Martians are some sort of beaver-like creature (Source: T. Elway, “Do Beavers Rule on Mars?” Popular Science (May 1930): 36–37)

A century later, in March 2004, the English bookmaker Ladbrokes stopped taking bets on life on Mars because the space rover Opportunity had found sulfates, which might indicate that the Martian surface had previously had water on it. Now, in late 2011 scientists are still arguing about whether or not they see evidence for water on Mars. Where one sees evidence of water, another sees evidence of vulcanism. As one commentator said back in 1913, “the question, therefore, becomes one of psychological optics rather than astronomy.”2

1 Alfred S. McEwen et al., “Seasonal Flows on Warm Martian SlopesScience 333 (5 August 2011): 740–43 argues tentatively for liquid water on Mars. David W. Leverington, “A volcanic origin for the outflow channels of Mars: Key evidence and major implicationsGeomorphology 132 (15 September 2011): 51–75 argues for volcanic origins of channel-like features.
2“Theory that Martians Exist Strongly Corroborated” NY Times (9 Nov. 1913), SM6.

Tags: a.s. eddington, alfred russel wallace, edward pickering, m.w. campbell, mars, percival lowell