born March 13, 1855, Boston, Mass., U.S.
died Nov. 12, 1916, Flagstaff, Ariz.
U.S. astronomer.
He was born into a distinguished Boston family. In the 1890s he built a private observatory in Flagstaff, Ariz., to study Mars . He championed the now-abandoned theory that intelligent inhabitants of a dying Mars had constructed a planetwide system of irrigation. He thought that the so-called canals of Mars (see Mars, canals of ) were bands of cultivated vegetation dependent on this irrigation. Lowell's theory, long vigorously opposed, was finally put to rest by images received from the U.S. Mariner spacecraft. His prediction of a planet beyond Neptune was vindicated when Pluto was discovered in 1930.