Tycho Brahe

Tycho Brahe (/ˈtaɪkoʊ ˈbrɑː(h)i, - ˈbrɑː(hə)/ TY-koh BRAH-(h)ee, -⁠ BRAH(-hə); Danish: [ˈtsʰykʰo ˈpʁɑːə] ^ⓘ; born Tyge Ottesen Brahe, Danish: [ˈtsʰyːjə ˈʌtəsn̩ ˈpʁɑːə]; 14 December 1546 – 24 October 1601), generally called Tycho for short, was a Danish astronomer of the Renaissance, known for his comprehensive and unprecedentedly accurate astronomical observations. He was known during his lifetime as an astronomer, astrologer, and alchemist. He was the last major astronomer before the invention of the telescope. Tycho Brahe has also been described as the greatest pre-telescopic astronomer.

In 1572, Tycho noticed a completely new star that was brighter than any star or planet. Astonished by the existence of a star that ought not to have been there, he devoted himself to the creation of ever more accurate instruments of measurement over the next fifteen years (1576–1591). King Frederick II granted Tycho an estate on the island of Hven and the money to build Uraniborg, the first large observatory in Christian Europe. He later worked underground at Stjerneborg, where he realised that his instruments in Uraniborg were not sufficiently steady. His unprecedented research program both turned astronomy into the first modern science and also helped launch the Scientific Revolution.

An heir to several noble families, Tycho was well educated. He worked to combine what he saw as the geometrical benefits of Copernican heliocentrism with the philosophical benefits of the Ptolemaic system, and devised the Tychonic system, his own version of a model of the Universe, with the Sun orbiting the Earth, and the planets as orbiting the Sun. In De nova stella (1573), he refuted the Aristotelian belief in an unchanging celestial realm. His measurements indicated that "new stars", stellae novae, now called supernovae, moved beyond the Moon, and he was able to show that comets were not atmospheric phenomena, as was previously thought.

In 1597, Tycho was forced by the new king, Christian IV, to leave Denmark. He was invited to Prague, where he became the official imperial astronomer, and built an observatory at Benátky nad Jizerou. Before his death in 1601, he was assisted for a year by Johannes Kepler, who went on to use Tycho's data to develop his own three laws of planetary motion.

Tycho Brahe was born as heir to several of Denmark's most influential noble families. In addition to his immediate ancestry with the Brahe and the Bille families, he counted the Rud, Trolle, Ulfstand, and Rosenkrantz families among his ancestors. Both of his grandfathers and all of his great-grandfathers had served as members of the Danish king's Privy Council. His paternal grandfather and namesake, Thyge Brahe, was the lord of Tosterup Castle in Scania and died in battle during the 1523 Siege of Malmö during the Lutheran Reformation Wars.

His maternal grandfather, Claus Bille, lord to Bohus Castle and a second cousin of Swedish king Gustav Vasa, participated in the Stockholm Bloodbath on the side of the Danish king against the Swedish nobles. Tycho's father, Otte Brahe, a royal Privy Councilor (like his own father), married Beate Bille, a powerful figure at the Danish court holding several royal land titles. Tycho's parents are buried under the floor of the church of Kågeröd, four kilometres west of Knutstorp Castle.

Tycho was born on 14 December 1546, at his family's ancestral seat at Knutstorp (Knudstrup borg; Knutstorps borg), about 8 kilometres (5.0 mi) north of Svalöv in then Danish Scania. He was the oldest of 12 siblings, 8 of whom lived to adulthood, including Steen Brahe and Sophia Brahe. His twin brother died before being baptized. Tycho later wrote an ode in Latin to his dead twin, which was printed in 1572 as his first published work. An epitaph, originally from Knutstorp, but now on a plaque near the church door, shows the whole family, including Tycho as a boy.

When he was only two years old Tycho was taken away to be raised by his uncle Jørgen Thygesen Brahe and his wife Inger Oxe, sister to Peder Oxe, Steward of the Realm, who were childless. It is unclear why Otte Brahe reached this arrangement with his brother, but Tycho was the only one of his siblings not to be raised by his mother at Knutstorp. Instead, Tycho was raised at Jørgen Brahe's estate at Tosterup and at Tranekær on the island of Langeland, and later at Næsbyhoved Castle near Odense, and later again at the Castle of Nykøbing on the island of Falster. Tycho later wrote that Jørgen Brahe "raised me and generously provided for me during his life until my eighteenth year; he always treated me as his own son and made me his heir".