While a young researcher working for the Lowell Observatory in Flagstaff, Arizona, Tombaugh was given the job to perform a systematic search for a trans-Neptunian planet ( also called Planet X ), which had been predicted by Percival Lowell and William Pickering.

He said he became interested in the concept after reading a translation of the work of Percival Lowell as a child.

Before the Mariner 4 spacecraft arrived at Mars in July 1965 and dispelled some of the more exotic theories about the planet, the conventional image of Mars was shaped by the observations of the astronomers Giovanni Schiaparelli and Percival Lowell.

* In Mass Effect ( 2007 ), an expedition launched by the European Space Agency discovers an ancient cache of advanced technology leftover from an alien race known as the Protheans ( The capitol of Mars is called " Lowell city " probably named after Percival Lowell who fueled the believe in possibility of alien structures on Mars ).

* 1916 – Percival Lowell, American amateur astronomer ( b. 1855 )

The search began in the mid-19th century and culminated at the start of the 20th with Percival Lowell's quest for Planet X. Lowell proposed the Planet X hypothesis to explain apparent discrepancies in the orbits of the gas giants, particularly Uranus and Neptune, speculating that the gravity of a large unseen ninth planet could have perturbed Uranus enough to account for the irregularities.

In 1894, with the help of William Pickering, Percival Lowell, a wealthy Bostonian, founded the Lowell Observatory in Flagstaff, Arizona.

Constance Lowell, Percival Lowell's widow, subsequently embroiled the observatory in a long legal battle to secure its million-dollar portion of Lowell's legacy for herself, which meant that the search for Planet X could not resume for several years.

The decision to name the object Pluto was intended in part to honour Percival Lowell, as his initials made up the word's first two letters.

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 14 years after his death.

Percival Lowell was a descendant of the Boston Lowell family.

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.

* November 12 – Percival Lowell, American astronomer ( b. 1855 )

* March 13 – Percival Lowell, American astronomer ( d. 1916 )

Based on this and other evidence, the idea that Mars was inhabited by intelligent life was put forward by a number of prominent scientists around the turn of the century, notably American astronomer Percival Lowell.

The idea of intelligent Martians was popularized by Percival Lowell and in fiction, especially by Edgar Rice Burroughs's John Carter ( Barsoom ) series, H. G.

In 1894, Massachusetts astronomer Percival Lowell hired A. E. Douglass to scout an ideal site for a new observatory.

The background of Mars presented in the novel, as a desert planet crisscrossed by giant canals built by an ancient civilization to bring water from the polar ice caps, is a common scenario in science fiction novels of the early 20th century, and was actually put forward as a plausible theory by some astronomers around the turn of the century, notably Percival Lowell mentioned in the novel.

* Amy Lowell ( 1874 – 1925 ), poet, critic, publisher, and sister of Abbott Lawrence and Percival Lowell

John Percival Hackworth, almost without thinking about it and without appreciating the ramifications of what he was doing, devised a trick and slipped it in under the radar of the Judge and Dr. X and all of the other people in the theatre, who were better at noticing tricks than most other people in the world.

Among the most fervent supporters of the artificial-canal hypothesis was the American astronomer Percival Lowell, who spent much of his life trying to prove the existence of intelligent life on the red planet.

Although ETH, as a unified and named hypothesis, is a comparatively new concept-one which owes a lot to the saucer sightings of the 1940s – 1960s, it can trace its origins back to a number of earlier events such as the now discredited Martian canals and ancient Martian civilization promoted by astronomer Percival Lowell, popular culture including the writings of H. G. Wells and fellow science fiction pioneers such as Edgar Rice Burroughs, who likewise wrote of Martian civilizations, and even to the works of figures such as the Swedish philosopher, mystic and scientist Emanuel Swedenborg, who promoted a variety of unconventional views that linked other worlds to the afterlife.

Lowell himself, despite his close association with Pickering, dismissed Planet O out of hand, saying, " This planet is very properly designated " O ", it is nothing at all.

" The object lay just six degrees from one of two locations for Planet X Lowell had suggested ; thus it seemed he had at last been vindicated.

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 in aperture.

In 1930 Clyde Tombaugh, working at the Lowell Observatory, discovered Pluto near the location expected for Planet X.

The generic description of the Martian met by Lowell is similar to the description of the Martians depicted in Stranger in a Strange Land and Red Planet.

Leuschner was one of the first astronomers to dispute Pluto as being Planet X as predicted by Lowell.

The first locomotives on the B & L were copies of the successful Planet class 2-2-0 built locally in Lowell.

* Project X Zone ( Yuri Lowell )

The constant involved in the big O notation was estimated in 1976 by Lowell Schoenfeld: assuming the Riemann hypothesis,

As stated by Jim Gettys, originator of X:

It is the originator of the phrasal template " X is the new Y ".

Kenneth E. Iverson, the originator of the APL programming language, believed that the Sapir – Whorf hypothesis applied to computer languages ( without actually mentioning the hypothesis by name ).

More recently Humboldt has also been credited as an originator of the linguistic relativity hypothesis ( more commonly known as the Sapir – Whorf hypothesis ), developed by linguists Edward Sapir or Benjamin Whorf a century later.

He is the originator and main proponent of the language bioprogram hypothesis according to which the similarity of creoles is due to their being formed from a prior pidgin by children who all share a universal human innate grammar capacity.

* 1966 – Derek Sherinian, American keyboard player, composer, and producer ( Planet X, Dream Theater, and Black Country Communion )

* 1960 – Tony MacAlpine, American guitarist, composer, and producer ( Planet X, CAB, Ring of Fire, and Seven the Hardway )

Tombaugh discovered nearly 800 asteroids during his search for Pluto and years of follow-up searches looking for another candidate for the postulated Planet X. Tombaugh is also credited with the discovery of comet C / 1931 AN, though its orbit is currently unknown.

Some realistic references to ARPA in fiction are in Tom Swift and the Visitor from Planet X ( DARPA consults on a technical threat ), in episodes of television program The West Wing ( the ARPA-DARPA distinction ), the television program Numb3rs ( DARPA research into creating the first self-aware computer ), and in the motion picture Executive Decision ( use of a one-of-a-kind experimental prototype in an emergency ).

** Leather Goddesses of Phobos 2: Gas Pump Girls Meet the Pulsating Inconvenience from Planet X!

In Batman: The Brave and the Bold TV series, a character named Rohtul ( Luthor spelled backwards ) appears in the episode " The Super-Batman of Planet X " portrayed by Clancy Brown.

Today, the astronomical community widely agrees that Planet X, as originally envisioned, does not exist, but the concept of Planet X has been revived by a number of astronomers to explain other anomalies observed in the outer Solar System.

In popular culture, and even among some astronomers, Planet X has become a stand-in term for any undiscovered planet in the outer Solar System, regardless of its relationship to Lowell's hypothesis.

In 1906, convinced he could resolve the conundrum of Uranus's orbit, he began an extensive project to search for a trans-Neptunian planet, which he named Planet X.

The X in the name represents an unknown and is pronounced as the letter, as opposed to the Roman numeral for 10 ( At the time, Planet X would have been the ninth planet ).

Lowell's hope in tracking down Planet X was to establish his scientific credibility, which had eluded him thanks to his widely derided belief that channel-like features visible on the surface of Mars were canals constructed by an intelligent civilisation.

In 1915, he published his Memoir of a Trans-Neptunian Planet, in which he concluded that Planet X had a mass roughly seven times that of the Earth — about half that of Neptune — and a mean distance from the Sun of 43 AU.

He assumed Planet X would be a large, low-density object with a high albedo, like the gas giants.

Lowell's sudden death in 1916 temporarily halted the search for Planet X.