Live Science
By
June 27, 2023
In 1906, astronomer and businessman Percival Lowell launched a search for “Planet X,” a hypothetical giant planet orbiting the sun beyond Neptune. Lowell was convinced that Planet X existed based on some supposed irregularities he had observed in the orbits of Neptune and Uranus. His belief eventually led to the discovery of Pluto in 1930, though scientists later determined that the dwarf planet was too small to have a gravitational impact on Neptune’s orbit (let alone Uranus’).