- Astronomer Clyde Tombaugh was born #OTD in 1906. He discovered Pluto in 1930, then traveled there in 2015 when NASA's New Horizons mission made its flyby with some of his ashes onboard. 🧪 🔭 Images: Lowell Observatory Archive; NASA/JHUAPL/SwRIFeb 4, 2026 15:29