Anders Ångström

Born on 13 August 1814 in Lögdö, Sweden, Anders Ångström was a physicist, solar astronomer, and pioneer in the field of spectroscopy. Ångström studied physics and astronomy at the University of Uppsala, earning his PhD in 1839. Upon graduation, he joined the faculty at the university, where he would remain for the rest of his career. In 1843 Ångström became an astronomical observer at the Uppsala Observatory, and in 1858 he became chair of the university’s physics department. One of his earliest research projects focused on heat conductivity, which he showed was proportional to electrical conductivity. His most important work involved spectral analysis. Ångström was the first to find hydrogen in the Sun’s atmosphere, and he published a detailed map of the solar spectrum in 1868. He was also the first to examine the spectrum of the aurora borealis, in 1867. Finding that the two spectra were different, he proposed that every substance has a unique spectrum. To express the wavelengths of electromagnetic radiation, he used a unit of length equal to 10^–10 m, which was later called the ångström in his honor. He and his collaborator Robert Thalén would go on to measure the spectral lines of many chemical elements. Ångström was elected to a number of scientific societies, including the Royal Swedish Academy of Sciences in 1850, the Royal Society of London in 1870, and the French Institute in 1873. He was awarded the Royal Society’s Rumford Medal in 1872. Ångström died in 1874 at age 59. (Image credit: AIP Emilio Segrè Visual Archives, W. F. Meggers Collection)

Date in History: 13 August 1814