Joseph Stefan

It’s the birthday of Joseph Stefan, who was born in 1835 in Klagenfurt, Austria. Stefan studied mathematics and physics at the University of Vienna. He rose through the ranks of the Austrian science establishment to become the director of the Physical Institute and vice-president of the Vienna Academy of Sciences. His most famous contribution to physics is the law that he derived experimentally in 1879 and that Ludwig Boltzmann derived theoretically in 1884: the Stefan-Boltzmann law, which states that the total energy emitted by a black body is proportional to the 4th power of its temperature. An ethnic Slovene, Stefan wrote poetry in his native language and promoted its use. Here’s a verse from his poem Hrasti (oaks): Vse tiho je okoli, le hrasti šepetajo, bog ve, kaj si toliko povedati imajo. All quiet around only whispering oaks, God knows what you so much have to say. Google Translate could not fully translate the rest of the poem.

Date in History: 24 March 1835