Anders Jonas Ångström (; 13 August 181421 June 1874) 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 ...

and one of the founders of the science of

spectroscopy Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter ...

.P.Murdin (2000): "Angstrom" chapter in ''Encyclopedia of Astronomy and Astrophysics''. Ångström is also well known for his studies of

astrophysics Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline said, Astrophysics "seeks to ascertain the nature of the h ...

, heat transfer, terrestrial magnetism, and the

aurora borealis An aurora (plural: auroras or aurorae), also commonly known as the polar lights, is a natural light display in Earth's sky, predominantly seen in high-latitude regions (around the Arctic and Antarctic). Auroras display dynamic patterns of bri ...

. In 1852, Ångström formulated in ''Optiska undersökningar'' (Optical investigations), a law of absorption, later modified somewhat and known as

Kirchhoff's law of thermal radiation In heat transfer, Kirchhoff's law of thermal radiation refers to wavelength-specific radiative emission and absorption by a material body in thermodynamic equilibrium, including radiative exchange equilibrium. It is a special case of Onsage ...

Biography

Anders Jonas Ångström was born in Medelpad to Johan Ångström, and schooled in

Härnösand Härnösand () is a locality and the seat of Härnösand Municipality in Västernorrland County, Sweden with 17,556 inhabitants in 2010. It is called "the gate to the High Coast" because of the world heritage landscape just a few miles north of H ...

. He moved to

Uppsala Uppsala (, or all ending in , ; archaically spelled ''Upsala'') is the county seat of Uppsala County and the fourth-largest city in Sweden, after Stockholm, Gothenburg, and Malmö. It had 177,074 inhabitants in 2019. Located north of the ca ...

in 1833 and was educated at

Uppsala University Uppsala University ( sv, Uppsala universitet) is a public research university in Uppsala, Sweden. Founded in 1477, it is the oldest university in Sweden and the Nordic countries still in operation. The university rose to significance during ...

, where in 1839 he became

docent The title of docent is conferred by some European universities to denote a specific academic appointment within a set structure of academic ranks at or below the full professor rank, similar to a British readership, a French " ''maître de conf ...

in physics. In 1842 he went to the

Stockholm Observatory The Stockholm Observatory ( sv, Stockholms observatorium, 050) is an astronomical observatory and institution in Stockholm, Sweden, founded in the 18th century and today part of Stockholm University. In 1931, the new Stockholm Observatory ( sv, ...

to gain experience in practical astronomical work, and the following year he was appointed keeper of the Uppsala Astronomical Observatory. Intrigued by terrestrial magnetism he recorded observations of fluctuations in magnetic intensity in various parts of Sweden, and was charged by the Stockholm Academy of Sciences with the task, not completed until shortly before his death, of working out the magnetic data obtained by on her voyage around the world in 1851 to 1853. In 1858, he succeeded Adolph Ferdinand Svanberg in the chair of physics at Uppsala. His most important work was concerned with

heat In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is ...

conduction and

. In his

optical Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultravio ...

researches, ''Optiska Undersökningar'', presented to the

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

in 1853, he not only pointed out that the electric spark yields two superposed spectra, one from the metal of the electrode and the other from the gas in which it passes, but deduced from

Leonhard Euler Leonhard Euler ( , ; 15 April 170718 September 1783) was a Swiss mathematician, physicist, astronomer, geographer, logician and engineer who founded the studies of graph theory and topology and made pioneering and influential discoveries ...

's theory of resonance that an incandescent gas emits luminous rays of the same refrangibility as those it can absorb.See: * Note: Although Ångström submitted his paper to the Swedish Royal Academy of Science on 16 February 1853, it was published in the volume for Academy's proceedings of 1852. * * This statement, as Sir

Edward Sabine Sir Edward Sabine ( ; 14 October 1788 – 26 June 1883) was an Irish astronomer, geophysicist, ornithologist, explorer, soldier and the 30th president of the Royal Society. He led the effort to establish a system of magnetic observatories in ...

remarked when awarding him the

Rumford medal The Rumford Medal is an award bestowed by Britain's Royal Society every alternating year for "an outstandingly important recent discovery in the field of thermal or optical properties of matter made by a scientist working in Europe". First awar ...

of the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

in 1872, contains a fundamental principle of spectrum analysis, and though overlooked for a number of years it entitles him to rank as one of the founders of spectroscopy. From 1861 onward, he paid special attention to the solar spectrum. His combination of the spectroscope with photography for the study of the

Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...

resulted in proving that the Sun's atmosphere contains

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-to ...

, among other elements (1862), and in 1868 he published his great map of the normal

solar spectrum Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when th ...

in ''Recherches sur le spectre solaire'', including detailed measurements of more than 1000

spectral line A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to ident ...

s, which long remained authoritative in questions of wavelength, although his measurements were inexact by one part in 7000 or 8000, owing to the metre he used as a standard being slightly too short. Recherches sur le spectre solaire

He was the first, in 1867, to examine the spectrum of the

, and detected and measured the characteristic bright line in its yellow-green region; but he was mistaken in supposing that this same line, which is often called by his name, is also to be seen in the

zodiacal light The zodiacal light (also called false dawn when seen before sunrise) is a faint glow of diffuse sunlight scattered by interplanetary dust. Brighter around the Sun, it appears in a particularly dark night sky to extend from the Sun's direction ...

. He was elected a member of a number of learned societies, including the

in 1850, the

in 1870 and the

Institut de France The (; ) is a French learned society, grouping five , including the Académie Française. It was established in 1795 at the direction of the National Convention. Located on the Quai de Conti in the 6th arrondissement of Paris, the institut ...

in 1873. He died in Uppsala on 21 June 1874. His son,

Knut Knut ( Norwegian and Swedish), Knud (Danish), or Knútur (Icelandic) is a Scandinavian, German, and Dutch first name, of which the anglicised form is Canute. In Germany both "Knut" and "Knud" are used. In Spanish and Portuguese Canuto is used ...

(1857–1910), was also a physicist.

Honours

The

Ångström The angstromEntry "angstrom" in the Oxford online dictionary. Retrieved on 2019-03-02 from https://en.oxforddictionaries.com/definition/angstrom.Entry "angstrom" in the Merriam-Webster online dictionary. Retrieved on 2019-03-02 from https://www.m ...

unit (1 Å = 10⁻¹⁰ m) in which the

wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tr ...

s of light and interatomic spacings in condensed matter are sometimes measured is named after him. The unit is also used in

crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids. Crystallography is a fundamental subject in the fields of materials science and solid-state physics ( condensed matter physics). The wor ...

as well as spectroscopy. The crater

on the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

is named in his honour. One of the main building complexes of

, the Ångström Laboratory, is named in his honour. This building houses various departments including the Department of Physics and Astronomy, Department of Mathematics, Department of Engineering Sciences, Institute of Space Physics, and the Department of Chemistry.

Death

Anders Ångström died in June 1874 from meningitis, shortly before his sixtieth birthday.

References

External links

* {{DEFAULTSORT:Angstrom, Anders Jonas 1814 births 1874 deaths Foreign Members of the Royal Society Members of the French Academy of Sciences Members of the Royal Swedish Academy of Sciences People from Timrå Municipality 19th-century Swedish astronomers 19th-century Swedish physicists Uppsala University alumni Spectroscopists Burials at Uppsala old cemetery Members of the Royal Society of Sciences in Uppsala

Biography

Honours

Death

See also

References

Further reading

External links