He invited Celsius to join the expedition, which began in and took the group through northernmost Sweden. Involvement with the project gained Celsius significant recognition and, upon his return to Uppsala, he was granted the authority and funds to establish a modern observatory there, which he completed in In addition to his early observations of the aurora borealis, Celsius carried out many other astronomical studies.
He developed a photometric method of measuring the intensity of starlight and assiduously cataloged the results he obtained for hundreds of stars. He also kept meteorological records, but was unhappy with the inaccuracy of thermometers in use at the time. Celsius devised a centigrade temperature scale for use with mercury thermometers that fixed the boiling point of water at zero and the freezing point of water at the degree mark.
Anders Celsius was born in Uppsala, Sweden, on November 27, The son of an astronomy professor and the grandson of a mathematician and an astronomer, Celsius chose a life in the world of academics. He studied at the University of Uppsala, where his father taught, and in he, too, was awarded a professorship there.
His earliest research concerned the aurora borealis also known as the northern lights, which are an unusually spectacular illumination of the night sky , and he was the first to suggest a connection between these lights and changes in the Earth's magnetic field. Celsius traveled for several years, including an expedition into Lapland with French astronomer Pierre-Louis Maupertuis — to measure a degree of longitude an angular distance of the earth.
Upon his return he was appointed steward manager to Uppsala's new observatory, a building designated for studying the universe. He began a series of observations using colored glass plates to record the magnitude size of certain stars.
This was the first attempt to measure the intensity of starlight with a tool other than the human eye. The work for which Celsius is best known is his creation of a hundred-point scale for temperature; although he was not Anders Celsius. Reproduced by permission of Archive Photos, Inc. What set Celsius's scale apart from all of the others was his decision to assign the freezing and boiling points of water as the constant temperatures at either end of the scale.
When Celsius introduced his scale in , it was the reverse of today's scale, with the boiling point of water being zero degrees and the freezing point being one hundred degrees.
A year later the two constants were switched, creating the temperature scale used today. Celsius originally called his scale centigrade from the Latin for "hundred steps". For years it was simply referred to as the Swedish thermometer. Albert Einstein was a physicist who developed the general theory of relativity. He is considered one of the most influential scientists of the 20th century.
Charles Darwin was a British naturalist who developed a theory of evolution based on natural selection. James C. Maxwell was a 19th-century pioneer in chemistry and physics who articulated the idea of electromagnetism. Anders Celsius was a Swedish astronomer who built the Uppsala Observatory and invented the Celsius or centigrade thermometer scale.
Together with his assistant Olof Hjorter he also was the first to realize that the aurora phenomenon has magnetic causes through observing the inclination of a compass-needle and finding that the larger deviations correlated with stronger aurora activity.
In astronomy he made observations of eclipses and various astronomical objects. The idea of his system consists of using identical transparent glass plates and viewing the ray of light from a star through them. He could then compare the magnitudes of the stars by the number of glass plates needed to extinguishe the light. The star Sirius, the brightest star in the sky, needed 25 of his plates to be extinguished.
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