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In the late 16th century, Tycho Brahe built an observatory on an island and collecting some of the most accurate data ever. He also lost his nose in a duel with a classmate -- over who was the better mathematician.

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Good astronomy means you need good data, and before the invention of the telescope in the 17th century, good data was hard to come by.  16th century astronomer Tycho Brahe tried to make his observations as accurate as possible anyway, and ended up revolutionizing how we think about astronomy.  He was also a little...unusual?


Brahe was born to rich, Danish nobles in 1546, and was kidnapped by his paternal uncle when he was around two.  His parents just let the man keep him.  When he was a teenager, he went to study law at the University of Copenhagen, but after seeing a solar eclipse in 1560, he decided to become an astronomer instead.  Then, in 1566, at the age of 20, he lost part of his nose in a duel with a classmate over who was a better mathematician, which is why he wore a metal, prosthetic nose for the rest of his life.  

Six years later, a new object appeared in the sky in the constellation Casseiopeia.  At the time, people thought space was unchangeable, so if anything new showed up in the sky, they assumed it was happening in Earth's atmosphere.  But Brahe noticed this new object, which we now know as a supernova, never appeared to change position relative to the stars around it.  He understood parallax, that's the closer an object is to an observer, the more it appears to change position when either it or the observer moves.  It's like when you're driving down the road, the tree in the foreground flies past you while the mountain range in the background stays put.  

When Brahe saw that the supernova didn't move separately from the other stars, he realized it couldn't be as close as the atmosphere.  A few years later, while observing a comet, Brahe saw that it did have parallax, but less than the moon, so it had to farther away.  That was another obvious change in the supposedly unchangeable outer space.  

By now, Brahe had been hired by King Frederick the II of Denmark, who gave him an entire island to do his science.  There, Brahe built an observatory called Uraniborg, and filled it with fancy equipment.  He improved upon simple instruments like quadrants and sextants for measuring angles and armillary spheres for modeling the sky by building giant elaborate versions of them and recalibrating them a lot.  It also helped that he collected data constantly, studying the sky not just every once in a while, but almost every single night.  He ended up cataloging more than 1,000 new stars, and his meticulous observations showed that they didn't seem to move at all, relative to one another.

This meant either the stars were so far away that the parallax was too slight to see, or there was no parallax at all, because Earth didn't move.  He thought it would make a lot more sense if Earth was sitting still, so he formed his own model of the solar system, a sort of intermediate step between Ptolemy's Earth-centric model and Copernicus' sun-centric model.   According to Brahe's idea, Earth stayed put at the center of the universe, orbited by the moon and the sun and stars, while the other planets in the solar system orbited the sun.

We now know that that wasn’t true -- obviously -- but it was a step in the right direction. When he wasn’t busy watching the sky, Brahe was busy being a sixteenth-century Gatsby. He was incredibly wealthy, and liked to spend his money on parties and novelties, like the pet that people called an elk but may have actually been a moose. Unfortunately, the elk-moose died after getting drunk at Brahe’s friend’s house and falling down some stairs. Then, rumors started going around that Brahe had an affair with Denmark’s queen, and her son Christian IV didn’t appreciate it. So when the young king took power in 1588, Brahe ran away to Prague, where he became the official imperial mathematician to Holy Roman Emperor Rudolph II.

There, he hired an assistant, a young German astronomer named Johannes Kepler, who you might know as the guy who went on to change how we think about orbits. In 1601, at the age of 54, Brahe went to his last party. He drank way too much, and supposedly refused to leave the banquet to relieve himself, because it would’ve been considered rude. Then, after 11 days of bladder pain, he died. It seems he ruptured his bladder from holding in his pee.

Even though Kepler was his assistant, Brahe kept most of his observations secret. So for a while, some people thought Kepler poisoned Brahe to get access to his data, and the pee thing was just a cover story. But when Brahe’s body was exhumed in 2010, researchers found no evidence of poisoning, so Kepler’s off the hook. Brahe’s observation catalogs were meant to be passed to his children, but Kepler took advantage of some confusion about the inheritance and took the data before his kids had a chance to. When Kepler looked over Brahe’s detailed observations on the motion of the planets, he realized that planets orbit the sun not in circles, but in ellipses. Being a part of this breakthrough was probably Brahe’s most important astronomical contribution of all. It’s just too bad he wasn’t alive for it.

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