Sunday, November 11, 2012

Percival Lowell and the Blood Vessels of Venus

Percival Lowell, shown during the middle of the
longest unwitting eye exam in history
 Astronomer Percival Lowell died 96 years ago on November 12, 1916. Everything I've ever read about him lauds his enormous contributions to the field of astronomy, but I'm really not quite sure what those contributions were.

Lowell was a rich guy, descended from a family of rich guys who arrived in Massachusetts about 15 years behind the Mayflower. Let me just give you an idea of how rich the Lowell family was: Percival's brother Lawrence was the president of Harvard University, and his sister Amy had enough free time to become a professional poet.

Percival graduated Harvard University in 1876, with a degree in mathematics. For ten years, he traveled the Orient writing and publishing three books about the history, psychology, and culture of Japan. By 1893 he had grown bored of travel, and turned his interests to planetary astronomy.

Planetary astronomy was all the rage in the 1890s, especially terrestrial planets like Venus and Mars. Lowell was especially taken by the writings of the Italian astronomer Giovanni Schiaparelli, who believed he viewed lines of channels or canals on Mars. Lowell believed in these canals as well, and built an observatory in Flagstaff, Arizona to confirm these sightings.
Lowell's Martian canals, 1896.

Percival Lowell cranked out three books about Mars, each volume loaded with dozens of sketches of the elaborate Mars canal system. He interpreted the canals as a last gasp construction of the dying Mars race, built to move dwindling water supplies from the polar ice caps to the parched equatorial regions. The whole idea seems maudlin and melodramatic, but after all, this was the Victorian age.

Lowell's observations of extraterrestrial canals weren't limited to the planet Mars. He also spotted a hub and spoke system constructed on the surface of Venus. Unlike Schiaparelli's Martian canals, Lowell was the only astronomer to note such features on Venus. In fact, Lowell only spotted these features when he narrowed the objective lens of his telescope to a mere half millimeter in front of his eye.

Not astronomy - - it's anatomy.
In 2003, retired optometrist Sherman Schultz figured out what Percival Lowell was actually seeing: the objective lens was reflecting shadows of blood vessels inside Lowell's eye. The map of Venus was in reality a map of the back of Percival Lowell's eyeball. It's quite likely that the canals of Mars were also a side effect of Percival Lowell's optical blood vessels. In any case, Mariner 4 eliminated the question of canals on Mars during its flyby of the Red Planet in 1965.

So, if Lowell's observation of canals on Mars was a bust, and the structures on Venus were a delusion, did he make any contribution in the field of planetary astronomy? An argument could be made that he helped in the discovery of the dwarf planet Pluto – – except, even in that adventure he was horribly mistaken on a planetary scale. Lowell, the mathematician, found a glaring gap in the gravity equations governing the motions of planets Uranus and Neptune. To account for the discrepancy, it seemed as though there was a third, more distant planet tugging on Neptune. This mysterious "Planet X" was Lowell's focus in the final decade of his life. Hundreds of photographic plates were made at the Lowell Observatory in Flagstaff, searching for a tiny dot in the sky to resolve the equation. The search continued long after Lowell had passed away, ending finally with the discovery by Clyde Tombaugh of the dwarf planet Pluto in 1930. Revisiting earlier photography, Tombaugh noted that Pluto had been imaged previously during Lowell's lifetime in 1916, but the tiny speck of Pluto had been overlooked.

It turns out that the entire search for Pluto had been a mathematical mistake in the first place. Spacecraft Voyager 2 confirmed that the planet Neptune was much less massive than Lowell had estimated, making the search for an additional planet unnecessary. Although the data was erroneous, Lowell's mistake set in motion the process of discovery that allowed Tombaugh to find Pluto.

Percival wasn't the only person in the Lowell household to see things that weren't there. His wife, Constance Lowell, was sued by a neighbor for "false arrest and malicious prosecution" after she claimed the neighbor had stolen twelve chickens (and a chicken coop). The neighbor was acquitted, and I can't find a record of how the civil suit turned out.
 Even though Lowell's astronomical work didn't do much to advance the science of astronomy his romantic notions of Martian canals gave birth to the science fiction stories of H.G. Wells and Ray Bradbury. Bad astronomy makes for great science fiction.

Lowell's tomb is in the shape of an observatory.
John Carter would approve.

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