Aarhus University Seal / Aarhus Universitets segl

Ole Rømer

Ole Rømer (1644 - 1710) was a Danish astronomer, engineer and commissioner of police, and the first person to measure a fundamental physical constant, namely the speed of light, in 1676. "Hesitation of Light” was a sensation, which was not immediately accepted in the scientific community. Drawing of Ole Rømer

Ole Rømer was born in Aarhus, and he graduated from Aarhus Katedralskole and the University of Copenhagen. He was involved in a publication of Tycho Brahe's observation journals, and assisted in locating Brahe’s observatory on the island of Hven. His work helped interpret Brahe’s observations more accurately. Although Ole Rømer accomplished quite a lot during his lifetime - he introduced the Gregorian calendar in Denmark, and directed the Round Tower Observatory - his determination of "the hesitation of light" is the achievement, he is remembered for.