odditiesanalysisThe Public Domain Review1877–1908 · Milan and Flagstaff
Percival Lowell's canals on Mars were probably a collective illusion of the eye
In 1877 Giovanni Schiaparelli mapped Mars and drew dim linear features he called canali, an Italian word that can mean either natural channels or man-made canals. Percival Lowell, a wealthy Bostonian, took the idea further in books from 1895 onward, arguing the lines were irrigation canals built by an advanced civilisation. Other observers with the same telescopes could not see them, and experiments showed people reproducing thin lines on Martian drawings that had none. The canals were most likely an illusion of human pattern recognition, with the Italian-to-English translation and the recent Suez Canal feeding the myth. Lowell's observatory in Flagstaff, Arizona, was still a major centre for planetary research and the search for Planet X.
Human vision looks for patterns and edges, especially when an image is faint and near the limit of resolution. When observers expect a feature, they tend to connect faint specks into lines. Repeated tests showed that people drawing from memory added lines that were not in the original image.
It is a clean example of how strong expectations can shape what careful observers report, and why independent confirmation matters in science. Lowell's ideas also fed H.G. Wells's and Orson Welles's Martian invasion stories.
Dramatic claims from a single observer have often failed to hold up when other researchers tried to replicate them, from Martian canals to later claimed discoveries. Independent verification is the usual safeguard.
Pluto's name partly honours Percival Lowell, whose initials are P L.
background
During the late 19th and early 20th centuries, it was erroneously believed that there were "canals" on the planet Mars. These were a network of long straight lines on Mars, observed by astronomers using early telescopes without photography, that were believed to be engineering works or waterways via the mistranslation of Schiaparelli’s term canali ("channels") into English as “canals.” Modern historians of science widely agree that the Martian canals were a perceptual and linguistic artifact, arising from telescope limitations combined with optical illusions.
They were first described by the Italian astronomer Giovanni Schiaparelli during the opposition of 1877, and attested to by later observers. The Irish astronomer Charles E. Burton made some of the earliest drawings of straight-line features on Mars, although his drawings did not match Schiaparelli's. Around the turn of the century there was even speculation that they were engineering works, irrigation canals constructed by a civilization of intelligent aliens indigenous to Mars.
From Wikipedia: Martian canals (CC BY-SA 4.0) ↗
Image: The Public Domain Review
