Celsius, Anders

Born Uppsala, Sweden, 27 November 1701

Died Uppsala, Sweden, 25 April 1744

Anders Celsius is known not only for “degrees Celsius” but also for degrees of latitude that helped verify the Newtonian universe.

Celsius succeeded his father Nils Celsius as Uppsala University’s professor of astronomy in 1730. (Both grandfathers were Uppsala professors.) Early publications discussed terrestrial surveying. In 1732 he undertook a tour of European observatories that ultimately resulted in obtaining instruments for a modern astronomical observatory at Uppsala University in 1741. Celsius began his astronomy career in earnest while at Nuremberg, with the publication of his 1732 auroral observations. His travels also led to participation in Pierre de Maupertuis ’s 1736 Lapland expedition.

One prediction of Isaac Newton ’s gravitational theory was that the Earth was an oblate spheroid in shape. Thus, measuring the length of 1° of latitude in both far northern Sweden and near the Equator should result...