Johann Gottfried Galle (Essay)

Johann Gottfried Galle

Born in June 9, 1812, to J. Gottfried Galle and Henriette Pannier Johann grew up in the small German town, Dübener Heide. Galle attended school in Radis, Germany, and was then selected by local Clergymen for secondary school at Wittenberg. Galle studied at Wittenberg from April 1825 until April 1830, when he moved on to study at the Berlin Academy of Sciences. One of his teachers, Encke, would prove to be vital to his future. In 1833 Gall began teaching mathematics; in March the following year he was made assistant teacher at the Friedrich-Werder Gymnasium.  While still teaching secondary school, Galle kept in touch with his old educator, Encke. In 1835, Encke had become the director of the newly rebuilt Berlin Observatory, and invited Galle to be his assistant.

            Galle spent the next 16 years of his life dedicated to astronomy, more specifically astrometry. Galle was a dedicated observer of comets, including Halley’s Comet’s 1835 passing, Boguslavky’s comet, and Encke’s comet. In 1839 to 1840, Galle discovered three of his own comets –this feat attracted attention from both experts and royalty. In 1836, Alexander von Humbolt invited Galle to assist him in computing the astronomical material he had collected while on his journeys. For about 30 years, Galle also frequently did computational work concerning the minor planets, especially Pallas. In 1838, Galle observed the crepe ring of Saturn (though he did not publish this discovery).

            With government funding, Galle received his doctorate in theoretical studies on March 1, 1845. His thesis, Olai Roemeri triduum observationum astronomicarum, was based upon unanalyzed data from three days of meridian observations made by the Danish astronomer Roemer in 1706. Thinking the observations could be of value to Urbain Le Verrier, Galle sent him a copy. Le Verrier replied with the presumed position of a planet beyond Uranus –computed mathematically by Le Verrier and John Couch Adams from Uranus’s motion. Le Verrier did not have access to adequate telescopes in Paris, so he asked Galle to confirm his predictions. Galle was the first to see the planet, less than 1 degree from the predicted position. With his assistant Heinrich d’Arrest, Galle located the planet within the first few minutes of searching. Galle wrote, “I discovered a star of the eighth magnitude—not at first glance, to tell the truth, but after several comparisons. Its absence from the chart was so obvious that we had to try to observe it. Encke, who had been informed of all the details, took part in the observation on the same night. We observed the star until early morning; but, despite all duplications of effort, we did not succeed in discerning a definite motion, although a trace of change in the required sense seemed to occur. Full of excitement, we had to wait for the evening of 24 September, when our research was also favored by the weather and when the existence of the planet was proved”. The planet was at first named “Le Verrier’s planet” but was changed to Neptune to fit the Greek mythological names. Galle was modest about this discovery, refusing to capitalize from it.

            After the Neptune discovery, Galle continued his research in Berlin under Encke. Along with several other findings, Galle made several distance measurements of double stars. In 1847, Galle published a list of all comet orbits computed up to that time. Accepting an opportunity to start an independent career, Galle took the position of director of the observatory at Breslau. Galle continued his work in Breslau for 46 years. Galle taught all aspects of astrometry and meteorology. Though he dedicated most of his efforts to studying comets and planetoids, Galle became an avid lecturer who attracted large audiences. Galle found out that there is a relationship between the meteor showers recorded over the centuries and the appearance of comets. This led him to attempt computing the orbit of the Lyrid meteor shower around the sun to show its connection to Comet 1861 I. Galle successfully established the relation between meteor showers and the decomposition of a parent comet, which he classified as hyperbolic. Galle determined solar parallax by using corresponding data on minor planets. Although he specifically didn’t make the discovery, Galle’s methods were used to discover Eros.   

The poor equipment available at Breslau prevented Galle from making any pioneering discoveries. However, he was still able to participate in astronomical-geodetical tasks. Galle assisted in the determinations of longitude between berlin and Breslau. A streetcar line further limited his visibility and led him to turn to examining the magnetism of the Earth in relation to the Northern Lights and other terrestrial and even cosmic conditions. Galle went on to publish a series of works on climatology and weather forecasting. Later works by Galle dabbled in several minor matters in an array of fields.

In 1857, Galle married C. E. M. Regenbrecht, a daughter of a Breslau professor. Before she died in 1887, the couple had two sons. One, Andreas, went on to be an astronomer and geodesist at Potsdam. During his life, Galle received many honors and memberships to numerous scientific societies around the globe. Galle died in Potsdam, Germany on July 10^th, 1910 at the incredible age of 98. His teachings left his legacy far from over.