Knut Johan Ångström (12 January 18574 March 1910) was a

Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate caus ...

. He was the son of physicist

Anders Jonas Ångström Anders Jonas Ångström (; 13 August 181421 June 1874) was a Swedish physicist and one of the founders of the science of spectroscopy.P.Murdin (2000): "Angstrom" chapter in ''Encyclopedia of Astronomy and Astrophysics''. Ångström is also wel ...

and studied in

Uppsala Uppsala (, or all ending in , ; archaically spelled ''Upsala'') is the county seat of Uppsala County and the List of urban areas in Sweden by population, fourth-largest city in Sweden, after Stockholm, Gothenburg, and Malmö. It had 177,074 inha ...

from 1877 to 1884, when he received his ''licentiat''-degree, before going for a short time to the

University of Strassburg The University of Strasbourg (french: Université de Strasbourg, Unistra) is a public research university located in Strasbourg, Alsace, France, with over 52,000 students and 3,300 researchers. The French university traces its history to the ea ...

(

Strasbourg Strasbourg (, , ; german: Straßburg ; gsw, label=Bas Rhin Alsatian, Strossburi , gsw, label=Haut Rhin Alsatian, Strossburig ) is the prefecture and largest city of the Grand Est region of eastern France and the official seat of the Eu ...

) to study with

August Kundt August Adolf Eduard Eberhard Kundt (; 18 November 183921 May 1894) was a Germans, German physicist. Early life Kundt was born at Schwerin in Mecklenburg. He began his scientific studies at Leipzig, but afterwards went to Berlin University. At fi ...

. Coming back to Uppsala, he completed his doctoral degree and was appointed lecturer in physics at the new university college in Stockholm (now

Stockholm University Stockholm University ( sv, Stockholms universitet) is a public research university in Stockholm, Sweden, founded as a college in 1878, with university status since 1960. With over 33,000 students at four different faculties: law, humanities, so ...

) in 1885. After a few years working there, he returned to Uppsala in 1891 and received the professorship of

Physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...

in 1896. He focused his research work on investigating the

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: * ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visi ...

of heat from the sun, terrestrial nocturnal emission and its absorption by the Earth's atmosphere, and to that end devised various delicate methods and instruments, including his electric compensation

pyrheliometer A pyrheliometer is an instrument for measurement of direct beam solar irradiance. Sunlight enters the instrument through a window and is directed onto a thermopile which converts heat to an electrical signal that can be recorded. The signal v ...

, invented in 1893, apparatus for obtaining a photographic representation of the infra-red spectrum (1895) and

pyrgeometer A pyrgeometer is a device that measures near-surface infra-red radiation spectrum in the wavelength spectrum approximately from 4.5 μm to 100 μm. It measures the resistance/voltage changes in a material that is sensitive to the net e ...

(abt. 1905). In 1900, Herr J. Koch, laboratory assistant to Knut Ångström, did not observe any appreciable change in the absorption of infrared radiation by decreasing the concentration of up to a third of the initial amount. This result, in addition to the observation made a couple of years before that the superposition of the water vapour absorption bands, more abundant in the atmosphere, over those of CO₂, convinced some geologists for a time that calculations by

Svante Arrhenius Svante August Arrhenius ( , ; 19 February 1859 – 2 October 1927) was a Swedes, Swedish scientist. Originally a physicist, but often referred to as a chemist, Arrhenius was one of the founders of the science of physical chemistry. He received ...

for warming were wrong; though subsequent work in following decades eventually vindicated Arrhenius. The experiment, however, was careless seen from the current perspective with erroneous result but of a historical significance in the development of the theory of the

greenhouse effect The greenhouse effect is a process that occurs when energy from a planet's host star goes through the planet's atmosphere and heats the planet's surface, but greenhouse gases in the atmosphere prevent some of the heat from returning directly ...

amplified by CO₂. He was elected a member of the

Royal Swedish Academy of Sciences The Royal Swedish Academy of Sciences ( sv, Kungliga Vetenskapsakademien) is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special ...

in 1893.

References

* Ångström K, 1900, "Ueber die Bedeutung des Wasserdampfes und der Kohlensäure bei der Absorption der Erdatmosphäre", ''Annalen der Physik'' Bd 3. 1900, p720-732. http://www.realclimate.org/images/Angstrom.pdf

External links

Olof Beckman, Anders Jonas and Knut Ångström
(in Swedish) {{DEFAULTSORT:Angstrom, Knut 1857 births 1910 deaths 19th-century Swedish physicists Uppsala University alumni 19th-century Swedish inventors Members of the Royal Swedish Academy of Sciences Burials at Uppsala old cemetery 20th-century Swedish physicists