Why is the sky dark at night? The 200-year history of a question that transformed our understanding of the universe

As dawn rose over the German city of Bremen on May 7, 1823, Heinrich Olbers put the finishing touches to an article that left his name in history. After the deaths of his wife and daughter, Dr. Olbers had recently given up his work as an opthalmologist to devote himself to his nocturnal passions: the stars, the moon, meteorites and comets.