Profile of Tycho Brahe, Danish Astronomer

Imagine having a boss who was a well-known astronomer, got all his money from a nobleman, drank a lot, and eventually had his nose bit off in the Renaissance equivalent of a bar fight? That would describe Tycho Brahe, one of the more colorful characters in the history of astronomy. He may have been a feisty and interesting guy, but he also did solid work observing the sky and conning a king into paying for his own personal observatory. Among other things, Tycho Brahe was an avid sky observer and built several observatories. He also hired and fostered the great astronomer Johannes Kepler as his assistant. In his personal life, Brahe was an eccentric man, often getting himself into trouble. In one incident, he ended up in a duel with his cousin. Brahe was injured and lost part of his nose in the fight. He spent his later years fashioning replacement noses from precious metals, usually brass. For years, people claimed he died of blood poisoning, but it turns out that two posthumous examinations show that his most likely cause of death was a burst bladder. However he died, his legacy in astronomy is a strong one.   Brahes Life Brahe was born in 1546 in Knudstrup, which currently is in southern Sweden but was a part of Denmark at the time. While attending the universities of Copenhagen and Leipzig to study law and philosophy, he became interested in astronomy and spent most of his evenings studying the stars. Contributions to Astronomy One of Tycho Brahe’s first contributions to astronomy was the detection and correction of several grave errors in the standard astronomical tables in use at the time. These were tables of star positions as well as planetary motions and orbits. These errors were largely due to the slow change of star positions but also suffered from transcription errors when people copied them from one observer to the next. In 1572, Brahe discovered a supernova (the violent death of a supermassive star) located in the constellation of Cassiopeia. It became known as Tychos Supernova and is one of only eight such events recorded in the historical records prior to the invention of the telescope. Eventually, his fame at observations led to an offer from King Frederick II of Denmark and Norway to fund the construction of an astronomical observatory. The island of Hven was chosen as the location for Brahes newest observatory, and in 1576, construction began. He called the castle Uraniborg, which means fortress of the heavens. He spent twenty years there, making observations of the sky and careful notes of what he and his assistants saw. After the death of his benefactor in 1588, the kings son Christian took the throne. Brahes support slowly dwindled due to disagreements with the king. Eventually, Brahe was removed from his beloved observatory. In 1597, Emperor Rudolf II of Bohemia intervened and offered Brahe a pension of 3,000 ducats and an estate near Prague, where he planned to construct a new Uraniborg. Unfortunately, Tycho Brahe fell ill and died in 1601 before construction was complete. Tychos Legacy During his life, Tycho Brahe did not accept Nicolaus Copernicus’s model of the universe. He attempted to combine it with the Ptolemaic model (developed by ancient astronomer Claudius Ptolemy), which had never been proved accurate. He proposed that the five known planets revolved around the Sun, which, along with those planets, revolved around Earth each year. The stars, then, revolved around Earth, which was immobile. His ideas were wrong, of course, but it took many years of work by Kepler and others to finally refute the so-called Tychonic universe.   Although Tycho Brahe’s theories were incorrect, the data he collected during his lifetime was far superior to any others made prior to the invention of the telescope. His tables were used for years after his death, and remain an important part of astronomy history. After Tycho Brahe’s death,  Johannes Kepler used his observations to calculate his own three laws of planetary motion. Kepler had to fight the family to get the data, but he eventually prevailed, and astronomy is much the richer for his work on and continuation of Brahes observational legacy.   Edited and updated by Carolyn Collins Petersen.