As early as 1905, Percival Lowell thought there was a planet (mysterious planet x’) beyond theĀ orbit of Neptune and he continued to search for it up until his death in 1916. Pluto…
As early as 1905, Percival Lowell thought there was a planet (mysterious planet x’) beyond theĀ orbit of Neptune and he continued to search for it up until his death in 1916. Pluto…