Percival Lawrence Lowell (March 13,1855 - November 12,1916) was an American businessman, author, mathematician and an astronomer.
In 1894, Lowell used his fortune to quickly build an observatory near Flagstaff in the clear, dry Arizona sky. He set up two borrowed refracting telescopes and set to work sketching the surface features of Mars, and he continued sketching and making measurements of Mars for more than 15 years. His observatory eventually housed an impressive 24-inch refractor made by Alvan Clark. The telescope remains in use at Lowell observatory to this day.
Percival Lowell will probably be best remembered as a really strong supporter of the theory that an advanced alien civilisation irrigated crops on Mars's surface with water drawn from the planets poles along a canal network.
Historians now believe the canals Lowell mapped were faint surface features or even his imagination.
In the 19th and early 20th century Americans astronomer Percival Lowell predicted Pluto's existence.
Percival Lowell 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.
Lowell also predicted a ninth planet– which he called Planet X– based on oddities in the orbits of Uranus and Neptune. He searched for Planet X himself until his death in 1916. The observatory’s staff continued the search until 1930, when Clyde Tombaugh discovered Pluto at Lowell Observatory. Though it turns out Pluto was too small to be Planet X, and the whole issue disappeared when, much later, accurate determination of the mass of Neptune showed the outer planets moved as expected.