On the night of 23 September 1846, Johann Gottfried Galle identified a new planet in the solar system, fulfilling mathematical predictions by Urbain Le Verrier. By comparing his observations against the Berliner Akademischen Sternkarte, he located the celestial body within one degree of the projected coordinates, marking a seminal moment in nineteenth-century celestial mechanics.
Early Career and Berlin Observatory
Born in 1812 near Radis, Galle attended the Friedrich-Wilhelms-Universität Berlin between 1830 and 1833. After serving as a teacher in Guben and Berlin, he joined the Berlin Observatory in 1835 as an assistant to Johann Franz Encke. Over sixteen years, he utilized a 22.5 cm Fraunhofer-refractor to conduct research. In 1838, he identified an inner dark ring of Saturn and discovered three comets between late 1839 and early 1840.
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Take the IQ test →The Neptune Discovery
In 1845, Galle earned his Dr. phil degree. Following his doctoral research, he communicated with Urbain Le Verrier, who had analyzed Uranus's orbital perturbations to infer the existence of an unknown planet. Upon receiving Le Verrier's coordinates on 23 September 1846, Galle and his assistant, Heinrich Louis d'Arrest, initiated a search. They identified an 8th-magnitude star not listed in the star charts. Subsequent tracking confirmed the object’s motion, establishing it as a planet. Despite his pivotal role, Galle consistently credited Le Verrier with the discovery.
Academic Leadership in Wrocław
In 1851, Galle transitioned to the Breslau Observatory in present-day Wrocław, becoming a professor at the Schlesischen Friedrich-Wilhelms-Universität Breslau in 1856. During his 45-year tenure, he focused on planetary orbit calculations, meteor trajectories, and the properties of the aurorae. He compiled data on 414 comets and authored over 200 scientific publications. He also served as the university Rector for the 1875/76 academic year.
Final Years and Legacy
Galle retired to Potsdam in 1897 and died there in 1910. Throughout his career, he received recognition including the Lalande Prize, the Order of the Red Eagle, and the rank of Knight of the Legion of Honour. His contributions are commemorated by the asteroid 2097 Galle, craters on both Mars and the Moon, and a ring of Neptune.
Fast facts
- Born: 1812, Radis, Kingdom of Prussia
- Died: 1910, Potsdam
- Education: Humboldt-Universität zu Berlin
- Discovery of Neptune: 23 September 1846
- Notable Awards: Lalande Prize (1846), Order of the Red Eagle
- Academic Positions: Professor, University of Wrocław
- Professional Affiliations: Bavarian Academy of Sciences and Humanities
- Final Resting Place: Wrocław
Questions readers ask
Did Galle consider himself the primary discoverer of Neptune?
No, he consistently refused the title, attributing the accomplishment to the theoretical work of Urbain Le Verrier.
What subjects did Galle investigate besides planetary science?
He studied climatology, the Earth's magnetic field, the path of meteors, and the height of the aurorae.
Achievements
- Knight of the Legion of Honour
- Notable work: discovery of Neptune
- Held posts at University of Wrocław
- Educated at Humboldt-Universität zu Berlin
- Fields of research: astronomy
