Jožef Stefan En

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Each year around 24 March the Institute organises the Days of Jožef Stefan to mark the birthday of this great Slovenian physicist. Over a period of one week, high-level scientific and cultural meetings are combined with open days at the Institute.

Jožef Stefan was also a poet. His earliest poems date from the years when his high school in Celovec started to teach the Slovene language. The poetry played an important role in his life.


Jožef Stefan (1835--1893) was one of the most distinguished physicists of the nineteenth century. Born to Slovenian parents in Sveti Peter near Celovec (Klagenfurt, Austria), he graduated in mathematics and physics at the University of Vienna. He was also interested in poetry and published a number of poems in Slovene. He taught physics at the University of Vienna, was Director of the Physical Institute, Vice-President of the Vienna Academy of Sciences and a member of several scientific institutions in Europe.

He is most famous for the law that relates the total radiation from a black body to the 4th power of its absolute temperature. This phenomenon was later derived theoretically by Ludwig Boltzmann and is universally known as the Stefan Boltzmann law.

Jožef Stefan was born on 24 of March 1835 in the village of Sv. Peter near Celovec. He attended the primary school in Celovec and his aptitude ensured that he was advised to continue with his schooling. In 1853 he went to Vienna to study mathematics and physics. He also attended courses on chemistry, anatomy and plant physiology. His was interested in philosophy, history, French and English. In 1858 he received his PhD, and in 1860 at the age of 25, he became a correspondent member of the Academy of Sciences in Vienna. In 1863 he became a professor of mathematisc and physics at the University of Vienna, and so became the youngest professor in Austro-Hungary. At the age of 30 he was a director of the Institute of Physics of the Vienna University and was appointed a full member of the Academy of Sciences.

Jožef Stefan was a widely respected individual. He held the post of dean at the Faculty of Arts and the post of rector at the university. He was also Secretary General and Vice-President of the Academy of Sciences and a president of the first Austrian Electrotechnical Association. Towards the end of 1892, while he was visiting a friend, he had a stroke. He died on 7 January 1893 and was buried in Vienna's central cemetery .

J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia, Telephone: +386 1 477 39 00, Fax: +386 1 251 93 85