Anders Celsius

Anders Celsius was born on November 27, 1701, in Uppsala into a distinguished family of mathematicians and scientists. Appointed Professor of Astronomy at Uppsala University in 1730, he embarked on an extensive scientific tour across Europe, collaborating with leading astronomers in Paris, London, and Rome.

In 1736, Celsius joined French astronomer Pierre Louis Maupertuis on the famous Lapland Geodetic Expedition to the Torne Valley. Their precise measurements of the length of a degree of meridian near the Arctic Circle confirmed Isaac Newton's theory that the Earth is an oblate spheroid flattened at the poles. In 1742, he presented his epoch-making centigrade temperature scale to the Royal Swedish Academy of Sciences, proposing 100 degrees as freezing and 0 as boiling (inverted after his death by Linnaeus). He built Sweden's first modern astronomical observatory in Uppsala before succumbing to tuberculosis at age forty-two.