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.

Ångström is also well known for his studies of astrophysics, heat transfer, terrestrial magnetism, and the aurora borealis. 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.

Biography Anders Jonas Ångström was born in Medelpad to Johan Ångström, and schooled in Härnösand. He moved to Uppsala in 1833 and was educated at Uppsala University, where in 1839 he became docent in physics. In 1842, he went to the Stockholm Observatory 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 conduction and spectroscopy. In his optical researches, Optiska Undersökningar, presented to the Royal Swedish Academy of Sciences 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's theory of resonance that an incandescent gas emits luminous rays of the same refrangibility as those it can absorb. She was the daughter of Jean Henric Bedoire and Catharina Henrietta Littorin and belonged to the Bedoire family, a Stockholm merchant family of Huguenot origin.

His son, Knut (1857–1910), was also a physicist.

Honors The Ångström unit (1 Å = 10−10 m) in which the wavelengths of light and interatomic spacings in condensed matter are sometimes measured is named after him. The unit is also used in crystallography as well as spectroscopy.

The crater Ångström on the Moon is named in his honour.

One of the main building complexes of Uppsala University, 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.