ANDERS CELSIUS: BIOGRAPHY, CONTRIBUTIONS AND INVENTIONS, PUBLISHED WORKS - BIOGRAPHIES - 2024

Anders Celsius (1701-1744) was a physicist and astronomer of Swedish origin, recognized for creating the centesimal scale of the thermometer known as 'degree Celsius', a name that was adopted in his memory.

He was the grandson of two great mathematicians, astronomers and university professors: his paternal grandfather was Magnus Celsius and, on the maternal side, Anders Spole. He was also the promoter of the construction of the observatory in his hometown, which was the first modern facility of its kind in Sweden.

Anders Celsius. Source: Olof Arenius

In addition to dedicating himself for 14 years to teaching astronomy, his participation in an expedition in Lapland was also highlighted, which sought to confirm Isaac Newton's belief that the shape of the earth is an ellipsoid flattened at the poles.

Along with Emanuel Swedenborg, Carl von Linné, and Carl Wilhelm Scheele, Celsius was one of the great scientists who introduced new trends in the natural sciences, the Newtonian worldview, and experimental research to Sweden.

Biography

Early years

On November 27, 1701, Anders Celsius was born in the Swedish city of Uppsala, located about 78 km northwest of Stockholm. His parents were Nils Celsius and Gunilla Maria Spole who had two other children, in addition to Anders. He was born into a family of astronomers and mathematicians, which exerted great influence from an early age.

His paternal grandfather was Magnus Celsius, a mathematics teacher, who made great contributions in simplifying the runic alphabet. On the maternal side, his grandfather was Anders Spole, professor of astronomy, who even built an astronomical observatory in his house, although it was destroyed by a fire in 1702.

Celsius's father was also a professor of mathematics and wrote a dissertation in which he stated that empirical observations and not theological doctrine were the pillars of astronomy. It was no wonder that Celsius soon followed in his family's footsteps.

At the age of twelve he managed to solve all the mathematical problems in a university textbook. He also grew up with access to the great family library of his grandfather Spole, who managed to survive the fire of 1702.

College beginnings

After graduating from high school, Anders studied astronomy, mathematics, and experimental physics. From the early 1720s he made observations for the astronomy professor Erik Burman and by 1724 he had published his first two articles, related to barometers. That year he also became assistant secretary of the Royal Society of Sciences in Uppsala.

After graduating Celsius became a substitute professor of mathematics at Uppsala University, and subsequently in 1730 he was assigned the chair of astronomy.

European trip and expedition to Torneå

Between 1732 and 1736 this Swedish astronomer traveled to various countries visiting societies and academies, in order to expand his knowledge and establish links for the Royal Society of Sciences in Uppsala. He visited Berlin, Nuremberg, Bologna, Rome, and Paris.

In the latter city he met Pierre de Maupertuis, who was preparing an expedition to measure a meridian in the north and check Newtonian theory. Celsius joined the expedition.

Previously, in 1735 he went to London to provide himself with the necessary instruments. The following year and up to 1737, the French expedition to Torneå, in northern Sweden (now Finland) was successfully carried out.

However, the French astronomer and geographer Jacques Cassini and his followers questioned the accuracy of the observations made during the expedition. Celsius participated in the debate that followed and published one of his great works, refuting the accusations and in defense of what was achieved.

His arguments and the findings of the expedition in Lapland were confirmed by a later measurement in Peru.

Return to Uppsala and last years

Upon his return to Uppsala, Celsius took a turn in teaching astronomy at the university, thanks to his new experiences and insights. This made it possible to improve the position of astronomy in Sweden, which had been in decline. As secretary of the Royal Society of Sciences in Uppsala, a position he held until his death, he was in charge of updating and keeping the institution alive.

His participation in the Lapland expedition earned him great fame and respect from the Swedish government. This undoubtedly worked in his favor when he requested a donation of the necessary resources to build a modern observatory in Uppsala.

With the acquisition of new instruments acquired abroad, he supervised the construction of this new observatory on Svatbäck Street, where his grandfather's had been. In 1740 he was appointed director of the astronomical observatory and two years later he moved into the building, the first modern facility of its kind in Sweden.

On April 25, 1744 in Uppsala, Anders Celsius died of tuberculosis, at the age of 42.

Contributions and inventions

Comparison of degrees Celsius and degrees Fahrenheit. Source: 85fce

During his travels through Europe, Celsius had studied the numerous temperature scales of the time, with the purpose of creating an international reference and making one simpler than that of the German physicist Daniel Gabriel Fahrenheit. For this he achieved the centesimal scale.

The great contribution of Celsius was his famous observation about the two "constant degrees" in a thermometer, easily reproducible. Although a 100-degree scale had previously been used, he manages to establish the benchmark for the freezing and boiling points of water.

The point corresponding to the temperature 0 ° C coincided with its boiling point of water at sea level, while the temperature of 100 ° C, was equivalent to the freezing temperature of water at sea level, so that a number indicated colder. Celsius originally called its scale centigrade, derived from Latin for "one hundred steps," but for years it was simply called a Swedish thermometer.

He took a series of experiments to justify his choice. It showed that the freezing point did not change with varying latitude or pressure and that the boiling point did not depend on the length of the boiling time or the origin of the water.

He further assured that the boiling point of water was reliable as a fixed point only with a defined barometric pressure, which he proposed to be 25.3 inches of mercury.

The original Celsius scale indicated a decrease in degrees when the heat increased and an increase when the cold increased, contrary to how it is known today. The scientist Carl von Linné (known as Carlos Linnaeus) would reverse this scale three years later and it would be adopted as the standard scale used today.

Expedition and other observations

In addition to inventing the Celsius temperature scale, he participated in an organized expedition to measure the arc of a meridian in Lapland. This allowed to verify Newton's theory that posed the flattening of the Earth at the poles.

Also in 1740 he tried to determine the magnitude of the stars in the constellation of Aries, using a purely photometric method that consisted of filtering the light through glass plates. This was the first attempt to measure the intensity of starlight with a tool other than the human eye.

He also studied the timing of the eclipses of Jupiter's moons and proposed a theory for the evolution of stars, indicating that the stars were planets like Mars that began to shine once all the water had evaporated.

It is also notable for being one of the first to find a correlation between deviations of the compass and changes in the Earth's magnetic field. He looked at the variations of a compass needle and found that larger deviations correlated with stronger auroral activity.

Published works

Among his outstanding works are in 1730 Dissertatio de Nova Methodo Distantiam Solis a Terra Determinandi (A dissertation on a new method for determining the distance of the Sun from the Earth) and in 1738 De Observationibus pro Figura Telluris Determinanda in Gallia Habitis, Disquisitio (Disquisition of observations made in France to determine the shape of the Earth).

In between his two great works, in the year 1732 in Nuremberg, Celsius published a collection of 316 observations of the aurora borealis that he had made over 16 years with the collaboration of other astronomers.

That same year he published an astronomical magazine with Michael Adelbulner, a German mathematician, physicist, physician and astronomer. It was entitled Commercium litterarium ad astronomiae incrementum inter huius scientiae amatores communi consilio institutum. It included information on future astronomical phenomena, news, and reviews. It was maintained for two years, achieving the publication of 45 issues.

In 1733, while in Italy, he helped with his observations to Eustachio Manfredi, who published a book with part of his contributions under the title Liber de gnomon meridian Bononiensi (Free from the shadow of the meridians of Bologna).

He also strove to create a catalog of stars and for this he wrote Constellatione Tauri 17 (Constellations of Taurus) and Constellatione Leonis (Constellations of Leo), among other works.

It was in 1742 that he described his thermometer in a document read before the Swedish Academy of Sciences.

References

1. Encyclopædia Britannica (2019, April 21). Anders Celsius. Recovered from britannica.com
2. "Celsius, Anders." Complete Dictionary of Scientific Biography. Recovered from Encyclopedia.com
3. NNDB (2019). Anders Celsius. Recovered from nndb.com
4. O'Connor, J and Robertson, E. (nd). Anders Celsius. MacTutor History of Mathematics archive, University of St Andrews. Recovered from history.mcs.st-andrews.ac.uk
5. Anders Celsius. (2019, September 3). Wikipedia, The Free Encyclopedia. Recovered from es.wikipedia.org
6. Degree Celsius. (2019, August 12). Wikipedia, The Free Encyclopedia. Recovered from es.wikipedia.org