US astronomer who predicted the existence of a planet beyond Neptune, starting the search that led to the discovery of Pluto 1930. In 1894 he founded the Lowell Observatory in Flagstaff, Arizona, where he reported seeing 'canals' (now known to be optical effects and natural formations) on the surface of Mars.
Lowell was born in Boston, Massachusetts, and studied mathematics at Harvard. He spent 16 years in business and diplomacy, mainly in the Far East, before taking up astronomy, becoming professor at the Massachusetts Institute of Technology 1902.
Influenced strongly by the work of Italian astronomer Giovanni Schiaparelli, Lowell set up his observatory at Flagstaff originally with the sole intention of confirming the presence of advanced life forms on Mars. He thought he could make out a complex and regular network of canals and regular seasonal variations that to him indicated agricultural activity. He led an expedition to the Chilean Andes in 1907 which produced the first high-quality photographs of the planet.