United States
On February 18, 1930, Clyde Tombaugh discovered Pluto at Lowell Observatory in Flagstaff, Arizona. Using photographic plates and a blink comparator, Tombaugh identified the faint planet beyond Neptune. The discovery expanded humanity’s understanding of the solar system and inspired decades of exploration. Although reclassified as a dwarf planet in 2006, Pluto remains a symbol of American astronomical achievement. The discovery also demonstrated how technological advances revolutionized planetary science.
