1781 William Herschel, the British astronomer, discovered the planet Uranus, marking the first planet ever identified through a telescope. 1881 Russian Tsar Alexander II was assassinated in St. Petersburg by members of the revolutionary organization Narodnaya Volya. 1930 The planet Pluto, discovered by astronomer Clyde Tombaugh, was officially announced by the Lowell Observatory. 1940 The … Continue reading This Day in History