See also: Centigrade

Summary biography

Anders Celsius is a erudite Swedish born with Uppsala the November 27th 1701 and died of the Tuberculose in the same city the April 25th 1744. He was professor of astronomy to the Université of Uppsala (founded in 1477). He is especially known general public to be at the origin of a relative scale of the Température S of which the unit, the Degree Celsius (ºC) honors its name.

Anders Celsius belonged to a family comprising of many scientists originating in Ovanåker, small town located in the province of Hälsingland at the north of Uppsala. As it was of use at the time in the Germanic and Scandinavian countries to Latinize family names, that of Centigrade is a Latinized version of the name of the presbytery (Högen). His/her grandfather on the paternal side as his grandfather on the maternal side was both of the professors at the university of Uppsala: Magnus Celsius was professor of astronomy, and Anders Spole was professor of astronomy. His/her father, the Nile Centigrade, were him-also professor of astronomy. As for Anders, very young famous for its bump of mathematics, he was salaried professor of astronomy in 1730, at the 29 years age.

Two years later, in 1732, it undertook a long voyage of studies through Europe (Germany, Italy, France) which lasted four years. In 1733, during this voyage, it published in Nuremberg a whole of 316 observations of northern lights made by itself and others between the years 1716 and 1732. He visited almost all the famous observatories of the time, and he worked there with many known astronomers, in particular with the Observatoire of Paris. He was made there lawyer of a measurement of the arc of the meridian line in Lapland. He thus went from oneself that little time after its return to Uppsala, in 1736, the Swedish authorities requires of him to take part in the forwarding of Lapland organized by the Academy of Science of Paris and directed by the French astronomer Pierre Louis Maupertuis. This one took place in the valley of the Torne, in the most septentrional part of the Sweden. Its goal was to measure the length of an arc of meridian line of 1º, in order to be able to validate or cancel the theory of the gravitation of Isaac Newton, which provided that the Earth was flattened with the poles, contrary to the geodetic observations of Jean-Dominique and Jacques Cassini in France, who seemed to indicate the shape of the Earth lengthened to the poles. In addition to Maupertuis and Celsius also in this famous forwarding the French academicians of great reputation Alexis Claude Clairaut and Pierre Charles took part Monnier.

The results obtained confirmed in a final way that Newton was right and that the Figure of the Earth was well a spheroid flattened with the poles. The participation of Centigrade in this forwarding was very advantageous for astronomy in Sweden. Indeed, become celebrates, Celsius succeeds in interesting the Swedish authorities in the construction of a modern astronomical observatory with Uppsala and providing the required funds. The observatory the Centigrade one was completed in 1741 and was equipped with the instruments that Celsius had bought during its long voyage abroad. Those counted among the best than the technology of the time could provide.

Today one hardly any more considers of the geodetic measurements, the meteorological observations and other work of the same kind like astronomical occupations, but of time Centigrade that formed well part of the work of an astronomer. Thus, Celsius took many geodetic measurements for the General Chart of Sweden and was one of the first to notice slow the rising fenno-Scandinavian above the sea level. However, it was mistaken on the origin in this general rising. It is known now that it is caused by a slow handing-over with balance of the Earth's crust depressed by enormous masses of Glace at the time of large the Glaciation S of the Quaternaire. On the other hand, Celsius believed that the sea water evaporated.

To carry out its meteorological observations, Celsius built a Thermomètre which was going to ensure a glory on a worldwide scale to him. The thermometer the Centigrade one was graduated so that 0 corresponded to the point of boiling of water, and 100 at the freezing point. The scale the Centigrade one is thus graduated in opposite direction of the scale centigrade which we currently know. It is only after the early death the Centigrade one, which has occurred in 1744, that his colleagues (it is thought that the initiative is allocated from there especially to the famous Swedish naturalist Carolus Linnaeus (Carl von Linné, 1707 - 1778) reversed the scale of Centigrade to give him its current form, namely 0 for the temperature of congelation of water, and 100 for its boiling point.

Assisted of Olof Hiorter, Anders Celsius studied the northern lights and was the first to explain the auroral phenomenon by the terrestrial magnetism. It arrived has this conclusion by observing the slope of a needle of compass and while realizing that more the strongest deviations were correlated with a more intense auroral activity.

In Astronomie Celsius observed many eclipse S and extremely varied objects astrnomic. It published catalogs magnitudes carefully given for a total of 300 stars, while making use of its own photometric system to which the average error is close to 0,4 magnitude. This one is based on the use of plates transparent glass identical: Centigrade compared the magnitudes of various stars by counting the number of such plates that it was necessary to superimpose so that the light of star looked through them dies out. Thus, for example, so that no light passes more for Sirius, the most brilliant star of the sky, it was necessary to superimpose twenty-five plates.

Centigrade implied itself much so that Sweden, protesting state, adopt finally the Gregorian calendar, even if this one were the work of a catholic pope. He hardly had success seemingly since the Gregorian calendar replaced the Julien calendar in Sweden only in 1753, more than nine years after the death of the large scientist.

The majority of work the Centigrade one were published, either in the publications of the Royal Company of Sciences of Uppsala, or in the publications of the Royal Academy of Sciences of Sweden. The first, founded in 1710, forms the oldest scientific company in Sweden and Celsius was the secretary of 1725 to its death in 1744, the second was only founded in 1739. He wrote a popularizing work of Arithmétique for the youth which reflects well the spirit of its time.

Anders Celsius rests beside his/her Magnus grandfather, in the church of Gamla Uppsala located at approximately five kilometers in the north of the center of Uppsala. A crater of the Moon bears its name.

Works

  • Nova Methodus distantiam solis has will terra determinandi (a new method to determine the distance from the Sun to the Earth), 1730.
  • Collection of 316 observations of northern lights , 1716 - 1732. Published in Nuremberg in 1733.
  • Of observationibus pro appeared telluris determinanda (On observations to determine the figure of the Earth), 1738.
  • Arithmetics for the Swedish Youth , 1741.

References

P. Collinder (1970). Swedish Astronomers 1477-1900 . Acta Universitatis Upsaliensis, Ser. C. 19.

External bonds

This text is based mainly on the biography published in English by the astronomical observatory of the University of Uppsala:
  • Biography from Uppsala Astronomical Observatory

See too

Simple: Centigrade Anders

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