Mars—Beyond the Red Horizon (4): Chapter 1 Observations and Theories—Science Driven by Mars (2)
1.6 Schiaparelli's "Canali"—The Beginning of the Canal Controversy
In 1877, Italian astronomer Giovanni Schiaparelli (1835–1910) observed the close approach of Mars at the Brera Observatory in Milan.
Mars was about 56 million kilometers from Earth that year, providing ideal conditions for telescopic observation. Using a 22-centimeter aperture refracting telescope, Schiaparelli sketched the Martian surface in detail.
What he saw were bright regions, dark regions, and thin, linear patterns connecting them.
Schiaparelli gave these systematic names. He assigned names derived from Greek mythology to the bright regions, such as "Hellas," "Elysium," and "Arcadia," and classical names to the dark regions, such as "Syrtis Major" and "Mare Cimmerium." He called the linear patterns "canali."
The word "Canali"
The Italian word "canali" is a neutral term meaning "channels" or "straits." Schiaparelli did not make a definitive claim as to whether these were natural terrain or artificial structures.
However, as the word was transmitted to the English-speaking world, it was translated as "canal"—an artificial waterway. This mistranslation triggered the Martian canal controversy.
A Period of Transition to Mechanical Objectivity
Schiaparelli's observations were situated at a turning point in the concept of objectivity in science.
In "Objectivity," science historians Lorraine Daston and Peter Galison argue that the concept of scientific objectivity has historically transformed.
In the 18th century, scientific depiction was based on the ideal of "Truth-to-Nature." This was the idea of excluding individual, accidental features to depict an idealized archetype—the essence. Botanists drew the typical form of a species rather than a specific individual.
But from the mid-19th century, a new ideal of objectivity emerged: "Mechanical Objectivity." This is the idea of achieving objectivity by excluding human intervention and having machines record automatically. The advent of photographic technology made this ideal possible.
Schiaparelli's observations were precisely at this transitional period.
The image of Mars seen through a telescope was always unstable due to atmospheric turbulence, optical aberrations, and the limitations of the observer's eye. Mars was only clearly visible for fleeting moments, and for the most part, it was blurred.
The observer's job was to integrate these fragmented images and extract constant patterns. This required training. One had to peer through a telescope for hundreds of hours, memorize the fleeting images, repeat sketches, and refine the patterns.
Schiaparelli was such a trained observer. He used a machine (the telescope), but human judgment was essential in the process of interpreting what that machine recorded and extracting it as a meaningful pattern.
However, this mode of observation was already being challenged by the "mechanical objectivity" of photographic technology.
The Concept of Albedo Features
What Schiaparelli recorded was not actual terrain. It was an "albedo feature"—an apparent terrain based on the brightness and darkness of the surface.
There are regions on the Martian surface with different solar reflectance (albedo). Bright regions are areas covered in sand and dust, while dark regions are areas where rock is exposed. Sandstorms occur seasonally, and as the sand moves, the patterns of light and dark change.
In other words, the "terrain" Schiaparelli saw was not fixed terrain, but a changing surface pattern. It was real, but it was a different kind of reality than geological terrain.
In the latter half of the 20th century, as high-resolution observations by space probes progressed, the correspondence between albedo features and actual terrain became clear. For example, "Syrtis Major" is actually a basaltic plain. "Hellas" is a massive impact basin. The linear terrain corresponding to Schiaparelli's "canali" did not exist.
Even so, Schiaparelli's nomenclature is still partially used today. The International Astronomical Union (IAU) manages Martian terrain names, but some names for albedo features have been preserved due to historical circumstances.
The Complexity of "Seeing"
What Schiaparelli's observations show is the complexity of "seeing."
He did not report falsehoods. He tried to record exactly what he saw. But the act of "seeing" itself already involved interpretation. Integrating fragmented images, extracting patterns, and giving them meaning.
Schiaparelli's map of Mars was the result of human observation during the transition to mechanical objectivity. And that map paved the way for the next stage—Lowell's canal theory.
1.7 Lowell and the Verification of Canals
Schiaparelli's observations were translated into French by the French astronomer Camille Flammarion (1842–1925). Here, a problem arose. Flammarion translated "canali" as "canal." In French and English, "canal" is a word that strongly suggests an artificial "waterway."
American businessman Percival Lowell (1855–1916), who read this translation, thought that intelligent life might exist on Mars and that they had built canals to transport water.
In 1894, Lowell invested his own fortune to build an observatory in Flagstaff, Arizona: the Lowell Observatory. He observed Mars intensively and "discovered" hundreds of canals. He sketched them precisely and created a map of a canal network covering the entire planet. Then, in 1895, he published a book titled "Mars."
The Intuition of an "Old Planet"
In this book, Lowell described Mars as follows:
"Mars is much older and more evolved than Earth. Because of this, its oceans have dried up, and it is arid and desertified. The intelligent life on Mars built a planet-wide canal network to transport limited water resources from the poles to the equator."
Lowell's image of Mars was a mixture of scientific observation, speculation, and imagination. But the important point is that Lowell sincerely believed in what he "saw."
Lowell's observations, like Schiaparelli's, were a product of observation during the transition to mechanical objectivity. He observed Mars for hundreds of hours, repeated sketches, and refined the patterns. Constructing meaningful patterns from fragmented images seen through a telescope was recognized as a skill for astronomers at the time.
Lowell had trained his eyes to find geometric patterns on the Martian surface. And to those eyes, the canals were "real."
Photographic Technology and Mechanical Objectivity
Other astronomers could not confirm Lowell's canals.
British astronomer Edward Walter Maunder (1851–1928) conducted an interesting experiment in 1903. He showed children a diagram of random spots on the Martian surface from a distance. The children perceived the spots as "lines."
This experiment suggested that human vision has a tendency to construct linear patterns from fragmented information. It suggested that Lowell's canals might be a product of human visual and cognitive pattern recognition rather than actual terrain on the Martian surface.
Even more important was the development of photographic technology. From the end of the 19th century to the beginning of the 20th century, astronomical photography was put into practical use. Photographic plates could be exposed for longer periods than the human eye and could record even faint light.
As Daston and Galison point out, the advent of photographic technology brought about a new ideal of "mechanical objectivity." The idea that excluding human subjectivity and having a machine record automatically is true objectivity.
However, Lowell's canals could not be confirmed in Martian observations using photographic plates. The photos showed mottled patterns of light and dark, but no clear linear structures were seen.
Mechanical objectivity was considered closer to the "truth" than observation by the human eye. Machines do not lie. Machines do not have expectations. Machines are objective.
The controversy lasted for decades, but it was settled by Mariner 4 in 1965. No canals were confirmed in the images sent back by Mariner 4. The Martian surface was covered in craters.
It seemed like a victory for mechanical objectivity. As we will see in Chapter 2, this "victory" was also not simple. The first images from Mariner 4 were hand-colored by technicians with colored pencils. Even in the age of mechanical objectivity, human hands and eyes were involved.
Scientific Error and Structural Correctness
Lowell's canal theory was scientifically incorrect.
But what is interesting is that the part of Lowell's description of Mars—"much older and more evolved than Earth, and because of this, its oceans have dried up, and it is arid and desertified"—strangely aligns with the findings of modern Martian science.
Mars is indeed a planet that "aged" faster than Earth. It lost its magnetic field, dissipated its atmosphere, and its water cycle collapsed. The canals did not exist, but ancient riverbeds did. There were no intelligent life forms, but there is a possibility that traces of life existed.
Lowell was wrong in the details, but correct in the structure.
Herein lies the complexity of observation. Lowell did not lie. He observed sincerely and interpreted sincerely. Observation and interpretation always take place in the interaction between technology and judgment. And that interaction sometimes produces false patterns.
Entering the 20th century, Martian observation moved into the era of "mechanical objectivity." But as we will see in Chapter 2, machines were not neutral recording devices either. Mars continues to appear in the interaction between observation technology and human judgment.
However, once we return to Lowell's era, another observation technology will support Lowell's hypothesis.
(Published 2026.2.23, Revised 3.3)