Alasdair Wilkins in io9:
A solar eclipse in 1560 inspired Brahe to become an astronomer, and he quickly realized the burgeoning science could only progress if it had observations that were systematic, accurate, and, above all, nightly. To that end, he refined old instruments and built new ones, and spent the rest of his life assembling one of the largest bodies of astronomical data in human history…and more on that in a moment.
But Brahe was far from a dry scholar. In 1566 at the age of 20, he lost part of his nose in a duel with another Danish nobleman named Manderup Parsbjerg. The duel is said to have started over a disagreement about a mathematical formula. Because 16th century Denmark didn't have resources like the internet to figure out who was right, the only solution was to try to kill each other. For the rest of his life, Brahe wore a prosthetic nose. His fake nose was likely made of copper, although he probably also had gold and silver noses around for special occasions.