# Fotoeins Fotografie

## Fotoeins Friday at Uni Vienna: Josef Stefan

Throughout the month, I’m highlighting notable physicists who’ve been memorialized within the Arcade Courtyard in the main building of the University of Vienna:

2 Apr: Lise Meitner;
9 Apr: Christian Doppler, Erwin Schrödinger;
16 Apr: Joseph Littrow, Karl Littrow;
23 Apr: Josef Stefan;
30 Apr: Ludwig Boltzmann.

These are all names whose work and discovery form the historical and scientific basis of my university education in the field of physics.

The memorial to Josef Stefan (Jožef Štefan) includes a small inscription:

Josef Stefan
Professor of physics, 1863-1893
Born 1835, died 1893

An important physics equation is the Stefan-Boltzmann Law, which describes how an object that absorbs all radiation falling on its surface emits radiative intensity I (radiation energy per unit time per unit area) that is proportional to the fourth power in temperature T; the other two quantities are constants: emissivity ε between 0 and 1, and the Stefan-Boltzmann constant σ:

$I \,=\, \epsilon \sigma T^4$

Both Stefan and Boltzmann are buried in Vienna’s Central Cemetery. Boltzmann’s gravestone includes his entropy equation. Stefan does not have his own grave; instead, his descendants in the Munk family have a gravestone.

The university’s historical main building is inside the city’s Old Town which has been inscribed as UNESCO World Heritage Site since 2001. I made the photo above on 16 May 2018 with a Fujifilm X70 fixed-lens prime and the following settings: 1/60-sec, f/3.2, ISO1000, and 18.5mm focal length (28mm full-frame equivalent). This post appears on Fotoeins Fotografie at fotoeins DOT com as https://wp.me/p1BIdT-iGt.

### One Response to “Fotoeins Friday at Uni Vienna: Josef Stefan”

This site uses Akismet to reduce spam. Learn how your comment data is processed.