Today is the birthday of astronomer Johann Gottfried Galle, born near Gräfenhainichen, Germany in 1812. He taught math and physics before taking a job at the Berlin Observatory. In September 1846 Galle received a letter from Urbain Le Verrier. The French mathematician and astronomer had analyzed perturbations in the orbit of Uranus and concluded that there was another planet in the solar system. Le Verrier asked Galle to look for this new planet in a certain part of the sky. On September 23, 1846 Galle spotted an uncharted object about 1° from the predicted location. He became the first person to knowingly observe the planet Neptune.
