Harald Bohr who was born on April 22nd 1887, was a mathematician and footballer. While studying mathematics at the University of Copenhagen, he played for the Danish national football team in the 1908 summer Olympics. Bohr returned home with a silver medal, after the Danes lost the final 2-0 to the host team, Great Britain, and became a Danish sporting hero. It’s said that when he defended his dissertation in 1910 there were more football fans in the audience than mathematicians!
Bohr’s mathematical work was studying ‘almost periodic functions’. A function is like a rule for translating between one group of numbers to another, and a periodic function is one that eventually repeats itself. As the name suggests, an almost periodic function comes close to repeating, but doesn’t quite manage it. They’re useful for studying planetary orbits, because the Earth doesn’t follow the exact same path around the sun each year.
Surprisingly, Harald wasn’t the only footballer in the family. His brother Niels Bohr was a decent goalkeeper, and the pair played together for the Danish club Akademisk Boldklub in 1905. However, Niels didn’t always keep his mind on the game, as he once admitted to his teammates that he had missed an easy save because his mind was on an interesting mathematical problem. He never made it to the Olympics like his brother, but Niels was awarded the Nobel Prize for Physics in 1922 for his work investigating the structure of atoms.