Background
Anders Jonas Ångström was born August 13, 1814, at Lögdö, Sweden. Angstrom was the second son of Johan Angstrom, a minister.
Anders Jonas Ångström, 1814 – 1874, Swedish physicist and one of the founders of the science of spectroscopy.
Angstrom attended elementary and secondary schools in Hamosand, then began his studies in mathematics and physics at the University of Uppsala in 1833. In 1839 he received a doctorate with a dissertation on the optics of conical refraction.
A part of the original construction drawing by Way, 1844 (Uppsala Observatory).
Anders Jonas Ångström, Swedish physicist, first to explore the spectrum of Aurora Borealis in 1867.
Anders Jonas Ångström, 1814 – 1874, Swedish physicist and one of the founders of the science of spectroscopy.
Anders Jonas Ångström, 1814 – 1874, Swedish physicist and one of the founders of the science of spectroscopy.
Anders Jonas Ångström, 1814 – 1874, Swedish physicist and one of the founders of the science of spectroscopy.
Angstrom attended elementary and secondary schools in Hamosand, then began his studies in mathematics and physics at the University of Uppsala in 1833. In 1839 he received a doctorate with a dissertation on the optics of conical refraction.
In 1872 Angstrom was awarded the Rumford Medal of the Royal Society of London.
A part of the original construction drawing by Way, 1844 (Uppsala Observatory).
Anders Jonas Ångström, Swedish physicist, first to explore the spectrum of Aurora Borealis in 1867.
Anders Jonas Ångström, 1814 – 1874, Swedish physicist and one of the founders of the science of spectroscopy.
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Astronomer physicist scientist spectroscopist
Anders Jonas Ångström was born August 13, 1814, at Lögdö, Sweden. Angstrom was the second son of Johan Angstrom, a minister.
Angstrom attended elementary and secondary schools in Hamosand, then began his studies in mathematics and physics at the University of Uppsala in 1833. In 1839 he received a doctorate with a dissertation on the optics of conical refraction.
After receiving a doctorate degree in 1839 from the University of Uppsala, Angstrom went to Stockholm Observatory in 1842 in order to gain experience in practical astronomy, and the following year he was appointed assistant professor of astronomy at Uppsala Observatory. He was professor of physics at Uppsala from 1858 until his death.
His most important physical papers are those on spectroscopy, but he also wrote on terrestrial magnetism and the conduction of heat. In February 1853 Angstrom presented his “Optiska undersdkningar” (“Optical Researches”) before the Stockholm Academy of Science. In this work, he observed that the spectrum of an alloy of two metals contained the spectrum of each of the constituent metals and that an electric spark yielded two superimposed spectra, one from the metal of the electrodes and the other from the gas through which it passed. He also compared terrestrial emission spectra with the dark lines of the solar spectrum and concluded that a terrestrial spectrum was essentially a reversal of a portion of the solar spectrum. Proceeding from Euler’s resonance theory, Angstrom deduced that an incandescent gas should emit spectral lines of the same wavelengths as those it absorbed, thus proposing a relationship between the emission and absorption spectra of a chemical element that was more fully and effectively presented by Gustav Robert Kirchhoff several years later.
After 1861 Angstrom intensively studied the spectrum of the sun, noting the presence of hydrogen in the solar atmosphere and confirming the probable existence there of a number of other elements. In 1868 he published his monumental Recherches sur le spectre solaire, which contained an atlas of the solar spectrum with measurements of the wavelengths of approximately a thousand lines determined by the use of diffraction gratings. Angstrom expressed his results in units of one ten-millionth of a millimeter—a unit of length that has been named the angstrom unit in his honor.
In order to have a precise basis for the new science of spectroscopy, accepted standards were needed. In 1861 Kirchhoff made a map of the solar spectrum and labeled lines with the corresponding scale readings of his own prismatic instrument. These rapidly became the almost universally accepted manner of designating spectral lines, but they were inconvenient because each observer had to correlate his own readings with those of the arbitrary Kirchhoff scale. Angstrom’s wavelength measurements provided a more precise and convenient reference and, after 1868, became a competing authoritative standard. Unfortunately, as was noted later, the length of the Uppsala meter was not 999.81 millimeters, the value used by Angstrom, but 999.94 millimeters. Eventually Angstrom’s scale was replaced as the accepted standard by the more precise tables published by Henry Augustus Rowland between 1887 and 1893.
In 1867 Angstrom was the first to examine the spectrum of the aurora borealis. A work on the spectra of the metalloids, which was begun some years previously, was completed by Tobias Robert Thalén, who actively assisted Angstrom for many years, and was published in 1875.
He died in Uppsala on 21 June 1874.
Angstrom’s most important physical paper titled “Optiska undersdkningar” (“Optical Researches”) was presented on February of 1853 before the Stockholm Academy of Science. In this work, he observed that the spectrum of an alloy of two metals contained the spectrum of each of the constituent metals and that an electric spark yielded two superimposed spectra, one from the metal of the electrodes and the other from the gas through which it passed. He also compared terrestrial emission spectra with the dark lines of the solar spectrum and concluded that a terrestrial spectrum was essentially a reversal of a portion of the solar spectrum. This work establishes Angstrom as one of several significant predecessors of Kirchhoff in formulating the foundations of modern spectroscopy.
He also was the first to examine the spectrum of the aurora borealis in 1867. Ångström’s studies of the solar spectrum led to his discovery, announced in 1862, that hydrogen is present in the Sun’s atmosphere. He was the first, who detected and measured the characteristic bright line of oxygen in its yellow-green region at 5577 angstroms, but he was mistaken in supposing that this same line is also to be seen in the zodiacal light. In 1868 he published his great map of the solar spectrum in Recherches sur le spectre solaire (“Researches on the solar spectrum”), in which wavelength values were given in units of 10−10 metre, a unit that came to be called the angstrom.
Angstrom’s scientific merit was widely recognized. He twice shared the Wallmarsh Prize of the Royal Academy of Stockholm, and in 1872 he was awarded the Rumford Medal of the Royal Society of London. Late in Angstrom’s life, his scientific work had to compete with various administrative duties. He was secretary of the Uppsala Scientific Society (1867-1874), a member of the Administrative Council of the city of Uppsala (1868-1873), and served the university as president of the Council of Economic Administration (1869-1874) and rector (1870-1871).
In opposition to the view that a given chemical element had a multiplicity of spectra, depending upon conditions, Angstrom remained a strong defender of the opinion that each chemical element had a single characteristic spectrum that remained essentially unchanged.
Angstrom was a member of scientific societies in Uppsala, Stockholm, Copenhagen, Berlin, Paris, and London, among others.
Anders Jonas Ångström married Augusta Bedoire (1820-1906) in 1845. He was the father of Augusta and Knutngström, and a grandfather of the meteorologist Andersngström. His son, Knut (1857–1910), was also a physicist.
Ångström’s son Knut Johan Ångström was also a physicist who worked in spectroscopy and taught at Uppsala University.
A work on the spectra of the metalloids, which was begun some years previously, was completed by Tobias Robert Thalén, who actively assisted Angstrom for many years, and was published in 1875.
