Astronomer and Swedish physicist who was born 27 November 1701 - where he/she remained all his life - in Uppsala, and died in the same city a 25 April 1744. He/She was director of the Astronomical Observatory of Uppsala, which he/she created, since 1740. There he/she managed to demonstrate the relationship between polar lights and the magnetic field. He/She studied the satellites of Jupiter and observed the variation in the sea level that occurs on the Swedish coasts.
Celsius is known as the inventor of the centesimal scale of the thermometer. Although this instrument is a very old invention, the history of their gradation is more whimsical. During the 16th century it was graduated as "cold" by placing it in a cave and "hot" exposing him to the rays of the summer sun or on the hot skin of a person. Later French Reaumur and the German Fahrenheit in 1714, graduated it based on the temperature of the ice in its melting point and the steam of water boiling, but the German scale ranged from 32 to 212 degrees, while the French did it from 0 to 80 degrees. In 1742, Celsius proposed to replace the German scientist by another whose operation was simple scale. So he/she created the centesimal scale that ranged from 0 to 100 degrees and invented the Mercury thermometer as is known in the countries that use the Celsius scale. The point corresponding to the temperature 0 coincided with the boiling point of the water while the temperature to 100 ° C was tantamount to freezing of water at sea level. Scale, therefore, indicated a drop in temperature when the heat increased, instead of as it is known at present. Fellow scientist Karl von Linné (known as Linnaeus) would invest this scale three years later. Celsius thermometer was known for years as "Swedish thermometer" by the scientific community, and only became popular 'thermometer Celsius' name from the s. XIX.
Celsius also worked in other scientific fields related to astronomy. So, during the years 1736 and 1737, demonstrated in collaboration with Pierre Louis Moreau de Maupertuis in a geophysical expedition to Lapland, the hypothesis about the flattening of the Earth that was established previously by Isaac Newton, was correct.
Among his most important works are: Dissertatio de methodo distantiam solis a terra (1730), Disputatio dimetiendi novo of novo fluviis Nerlandorum in piscandi mode (1738), Disquisitio of observationibus pro appears telluris determinanda i Gallia habitis (1738), lunan non habitabili (1741), letter concerning comets (1744) and observations made in France to determine the figure of the Earth.