13 August 1814 21 June 1874 The Swedish physicist Anders Jonas Angstrom was born in August, in Sweden, on 13 August 1814. Today he is remembered as one of the founders of the science of spectroscopy. In 1843 just 29 years he was appointed Director of the Astronomical Observatory of the city of Uppsala; in 1858, he became Professor of Physics in the same city.
The studies
Anders Jonas Angstrom is famous in the field of science for his work on magnetism, on heat and on optics, but above all to study the phenomenon of Aurora Borealis.
The Sun and hydrogen
Angstrom demonstrated in 1862 that the Sun's atmosphere contains hydrogen: to do this, he used a combination of the spectroscope with photography. He published his research on the solar spectrum in Recherches sur le spectre solaire (1868), including detailed measurements of more than 1000 spectral lines.
Spectral analysis
In a paper presented at the Academy of Stockholm 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 for 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 refractive capacity than it can absorb. This statement contains a fundamental principle of spectrum analysis: although for several years his studies were neglected, today science is unanimous in indent Angstrom among the founders of spectroscopy. For these studies received the Rumford Medal by the Royal Society, 1872.
The Aurora Borealis
He was the first physicist to examine the spectrum of the aurora borealis (in 1867): ne identified, measured, the characteristic bright line in its yellow-green region.
The unit of measure that bears his name
In recognition of his contributions to spectroscopy theunit of measurement of wavelengths of the rows is defined Ångström: (1 Å = 0.1 nm). This unit is used in crystallography as well as spectroscopy. Anders Jonas Angstrom died shortly before he turned 60 years old, in Uppsala, 21 June 1874.
The scientific legacy passed on to son
His son, Knut Ångström (1857-1910), he was known for his research at Uppsala University on solar radiation, heat radiation from the Sun and its absorption by the Earth's atmosphere. For his research, he devised various delicate methods and instruments, including Knut on electric compensation pyrheliometer, invented in 1893, and an apparatus for obtaining a photographic representation of the infrared spectrum, in 1895.