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

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 cau ...

. He was the son of physicist

Anders Jonas Ångström Anders Jonas Ångström (; ; 13 August 1814 – 21 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 a ...

and studied in

Uppsala Uppsala ( ; ; archaically spelled ''Upsala'') is the capital 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 inhabitants in 2019. Loc ...

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

Strasbourg Strasbourg ( , ; ; ) is the Prefectures in France, prefecture and largest city of the Grand Est Regions of France, region of Geography of France, eastern France, in the historic region of Alsace. It is the prefecture of the Bas-Rhin Departmen ...

) to study with

August Kundt August Adolf Eduard Eberhard Kundt (; 18 November 1839 – 21 May 1894) was a German physicist known for developing Kundt's tube, an appartus used to measure the speed of sound in gases and solids. Early life Kundt was born in Schwerin, Meckle ...

. 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 (SU) () is a public university, 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, social ...

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

Physics Physics is the scientific study of matter, its Elementary particle, 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 whi ...

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 a material medium. This includes: * ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...

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 that can measure 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 vol ...

, invented in 1893, apparatus for obtaining a photographic representation of the infra-red spectrum (1895) and pyrgeometer (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 Swedish scientist. Originally a physicist, but often referred to as a chemist, Arrhenius was one of the founders of the science of physical chemistry. In 1903, 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 occurs when greenhouse gases in a planet's atmosphere insulate the planet from losing heat to space, raising its surface temperature. Surface heating can happen from an internal heat source (as in the case of Jupiter) or ...

amplified by CO₂. He was elected a member of the

Royal Swedish Academy of Sciences The Royal Swedish Academy of Sciences () 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 responsibility for promoting nat ...

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