Anders Jonas Angstrom and solar spectroscopy

Anders Jonas Angstrom and solar spectroscopy

Anders Jonas Angstrom was born on August 13, 1814 in Lodgo, Sweden. He studied at the University of Uppsala. After graduating, he taught physics at that same university from 1839 until his death. Since 1867 he was secretary of the Royal Science Society of Uppsala. He worked in the observatories of Uppsala and Stockholm.

His most important work was done in the subject of spectroscopy. It was his research that led him to discover that the wavelengths absorbed by a body are the same as those emitted when heated.

The combination of spectroscopy and photography was the key to its success. In 1862, studying the solar spectrum, he found hydrogen in his atmosphere. Angstrom was the first to analyze the spectrum of the aurora borealis, in 1867. Then, in 1868, he published a complete spectrographic map of the sun: "Recherches sur le specter solaire", which includes detailed measurements of more than 1000 spectral lines.

In a paper presented to the Stockholm Academy in 1853, he not only pointed out that an electric spark produces two superimposed spectra, one of the metal of the electrode and the other of the gas in which it occurs, but that it deduced, from the theory of resonance by Leonhard Euler, that an incandescent gas emits light rays with the same refractive capacity as those it can absorb. This statement by Anders Angstrom contains one of the fundamental principles of spectrum analysis.

To express the wavelengths he used as a unit of measurement the ten-millionth part of a millimeter and which, as a tribute to him, is known as Angstrong. It is used in atomic measurements and for wavelengths of electromagnetic radiation. The symbol of the angstrom is Å.

He studied the thermal conductivity of the bodies and correlated it with their electrical conductivity. He carried out multiple work measuring geomagnetic forces in different parts of Sweden.

He died in Uppsala in 1874.

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