Percival Lawrence Lowell (March 13, 1855 – November 12, 1916) was an American businessman, author, mathematician, and astronomer who fueled speculation that there were canals on Mars, founded the Lowell Observatory in Flagstaff, Arizona, and formed the beginning of the effort that led to the discovery of Pluto fourteen years after his death. The choice of the name Pluto and its symbol were partly influenced by his initials PL.

 

Percival Lowell was a scion of the Boston, Massachusetts Lowell family. His brother A. Lawrence was the president of Harvard University, and his sister Amy was an imagist poet, critic, and publisher.

 

Percival graduated from the Noble and Greenough School in 1872 and Harvard University in 1876 with distinction in mathematics. At his college graduation, he gave a speech, considered very advanced for its time, on the "Nebular Hypothesis." He was later awarded honorary degrees from Amherst College and Clark University.

 

In the 1880s, Lowell traveled extensively in the Far East. In August 1883, he served as a foreign secretary and counsellor for a special Korean diplomatic mission to the United States. He also spent significant periods of time in Japan, writing books on Japanese religion, psychology, and behavior. His texts are filled with observations and academic discussions of various aspects of Japanese life, including language, religious practices, economics, travel in Japan, and the development of personality. Books by Percival Lowell on the Orient include Chosön: The Land of the Morning Calm (1886, Boston), Noto: An Unexplored Corner of Japan (1891) and Occult Japan, or the Way of the Gods (1894); the latter from his third and final trip to the region. The most popular of Lowell's books on the Orient, The Soul of the Far East, (1888) contains an early synthesis of some of his ideas, that in essence, postulated that human progress is a function of the qualities of individuality and imagination.

 

He was elected a Fellow of the American Academy of Arts and Sciences in 1892. Beginning in the winter of 1893-94, using his wealth and influence, Lowell dedicated himself to the study of astronomy, founding the observatory which bears his name. For the last 23 years of his life astronomy, Lowell Observatory, and his and others' work at his observatory were the focal points of his life. He lived to be 61 years of age.

 

World War I very much saddened Lowell, a dedicated pacifist. This, along with some setbacks in his astronomical work (described below), undermined his health and contributed to his death from a stroke on November 12, 1916. Lowell is buried on Mars Hill near his observatory.

 

Lowell became determined to study Mars and astronomy as a full-time career after reading Camille Flammarion's La Planète Mars. He was particularly interested in the canals of Mars, as drawn by Italian astronomer Giovanni Schiaparelli, who was director of the Milan Observatory.

 

In 1894 Lowell chose Flagstaff, Arizona Territory as the home of his new observatory. At an altitude of over 2100 meters (7000 feet), with few cloudy nights, and far from city lights, Flagstaff was an excellent site for astronomical observations. This marked the first time an observatory had been deliberately located in a remote, elevated place for optimal seeing.

 

For the next fifteen years he studied Mars extensively, and made intricate drawings of the surface markings as he perceived them. Lowell published his views in three books: Mars (1895), Mars and Its Canals (1906), and Mars As the Abode of Life (1908). With these writings, Lowell more than anyone else popularized the long-held belief that these markings showed that Mars sustained intelligent life forms.

 

His works include a detailed description of what he termed the 'non-natural features' of the planet's surface, including especially a full account of the 'canals,' single and double; the 'oases,' as he termed the dark spots at their intersections; and the varying visibility of both, depending partly on the Martian seasons. He theorized that an advanced but desperate culture had built the canals to tap Mars' polar ice caps, the last source of water on an inexorably drying planet.

 

While this idea excited the public, the astronomical community was skeptical. Many astronomers could not see these markings, and few believed that they were as extensive as Lowell claimed. As a result, Lowell and his observatory were largely ostracized. Although the consensus was that some actual features did exist which would account for these markings, in 1909 the sixty-inch Mount Wilson Observatory telescope in Southern California allowed closer observation of the structures Lowell had interpreted as canals, and revealed irregular geological features, probably the result of natural erosion.

 

The existence of canal-like features were definitively disproved in the 1960s with NASA Mariner missions. Mariner 4, 6, 7, and the Mariner 9 orbiter (1972) did not capture images of canals but instead showed an ancient cratered Martian surface. Today, the surface markings taken to be canals are regarded as an optical illusion.

 

Although Lowell was better known for his observations of Mars, he also drew maps of the planet Venus. He began observing Venus in detail in the summer of 1896 soon after the 61-centimeter (24-inch) Alvan Clark & Sons refracting telescope was installed at his new Flagstaff, Arizona observatory. Lowell observed the planet high in the daytime sky with the telescope's lens stopped down to 3 inches in diameter to reduce the effect of the turbulent daytime atmosphere. Lowell observed spoke-like surface features including a central dark spot, contrary to what was suspected then (and known now): that Venus has no surface features, being covered in an atmosphere that is opaque. It has been noted in a 2003 Journal for the History of Astronomy paper and in an article published in Sky and Telescope in July 2003 that Lowell's stopping down of the telescope created such a small exit pupil at the eyepiece, it may have become a giant ophthalmoscope giving Lowell an image of the shadows of blood vessels cast on the retina of his eye.

 

Lowell's greatest contribution to planetary studies came during the last decade of his life, which he devoted to the search for Planet X, a hypothetical planet beyond Neptune. Lowell believed that the planets Uranus and Neptune were displaced from their predicted positions by the gravity of the unseen Planet X. Lowell started a search program in 1906 using a camera 5 inches (13 cm) in aperture. The small field of view of the 42-inch (110 cm) reflecting telescope rendered the instrument impractical for searching. From 1914 to 1916, a 9-inch (23 cm) telescope on loan from Sproul Observatory at Swarthmore, PA was used to search for Planet X.

 

In 1930 Clyde Tombaugh, working at the Lowell Observatory, discovered an object that was quickly dubbed Pluto near the location expected for Planet X. Partly in recognition of Lowell's efforts, a stylized P-L monogram – the first two letters of the new planet's name and also Lowell's initials – was chosen as Pluto's astronomical symbol. However, it would subsequently emerge that the Planet X theory was mistaken.

 

Pluto's mass could not be determined until 1978, when its satellite Charon was discovered. This confirmed what had been increasingly suspected: Pluto's gravitational influence on Uranus and Neptune is negligible, certainly not nearly enough to account for the discrepancies in their orbits. In 2006, the International Astronomical Union reclassified Pluto as a dwarf planet, part of a growing category of Pluto-sized objects in the outer solar system.

 

In addition, it is now known that the discrepancies between the predicted and observed positions of Uranus and Neptune were not caused by the gravity of an unknown planet. Rather, they were due to an erroneous value for the mass of Neptune. Voyager 2's 1989 encounter with Neptune yielded a more precise value of its mass, and the discrepancies disappear when using this value.

 

Although Lowell's theories of the Martian canals, of surface features on Venus, and of Planet X are now discredited, his practice of building observatories at the position where they would best function has been adopted as a principle. He also established the program and setting which made the discovery of Pluto and the superclustering of galaxies by Clyde Tombaugh possible. Craters on the Moon and on Mars, and the minor planet (1886) Lowell have been named after him. Lowell has been described by other planetary scientists as "the most influential popularizer of planetary science in America before Carl Sagan".

 

While eventually disproved, Lowell's vision of the Martian canals as an artifact of an ancient civilization making a desperate last effort to survive, significantly influences the development of science fiction – starting with H.G. Wells' influential The War of the Worlds, which made the further logical inference that creatures from a dying planet might seek to invade Earth.

 

Lowell's influence on science fiction remains strong. The canals figure prominently in Red Planet by Robert A. Heinlein (1949) and The Martian Chronicles by Ray Bradbury (1950).

 

Percival Lowell was elected an Honorary Fellow of the Royal Astronomical Society of Canada at a special meeting at Toronto's Central Technical School on 1916-04-27 on the occasion of his special visit. Five other honorary fellows were elected at the same meeting: Backlund, Baillaud, Dyson, Schlesinger and Turner. Lowell passed away less than seven months later.