Percival Lowell

After graduating from Harvard, he spent years traveling in East Asia and wrote books about Japan and Korea before turning fully to astronomy. In the 1890s he founded Lowell Observatory in Flagstaff, Arizona, choosing the site for its clear, high skies and using it as a base for his studies of Mars and the wider solar system.

He became famous for arguing that the lines he saw on Mars were canals, a claim that captured the public imagination even though later observations did not support it. He also promoted the idea of an unseen planet beyond Neptune and began a search for it at his observatory.

Lowell died in 1916, but the institution he built continued that work. In 1930, Clyde Tombaugh discovered Pluto at Lowell Observatory, linking Lowell's name permanently with one of the most famous chapters in planetary astronomy.