On Sept. 25, 1644, Ole Roemer was born in Aarhus, Denmark. Beginning in 1662, he studied at the University of Copenhagen with physicist Erasmus Bartholin, who tasked him with editing the manuscripts of Tycho Brahe; then, after a 1672 move to Paris, he spent eight years at the Paris Observatory and tutored the crown princeContinue reading "Sept. 25, 1644: The birth of Ole Roemer"