Lowell, Percival

(1855–1916) US astronomer: predicted existence and position of Pluto.

Son of a wealthy Boston family, Lowell travelled extensively after graduating from Harvard. His sister Amy was a major poet and his brother became president of Harvard. Lowell’s interest in astronomy was first stimulated by report in 1877 of ‘canali’ on Mars. He became convinced that Mars was inhabited by an intelligent race and wrote books on the subject. At the beginning of this century such views were not so ridiculous as they appear today, and the excellent observatory he built in Arizona in 1894 at a height of 2200 m became an important centre for planetary studies. However, Lowell’s most important contribution was the prediction (based on its gravitational influence on Uranus), of a ninth planet beyond Neptune. Although he himself searched for it from 1905 until 1914, Pluto was not detected until 1930 by, working at Lowell’s own observatory. It was named after the Greek god of outer darkness.