Tycho Brahe

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Tycho Brahe

Monument of Tycho Brahe and Johannes Kepler in Prague

Tycho Brahe, born Tyge Ottesen Brahe (December 14 1546 – October 24 1601), was a Danish nobleman from the region of Scania (in modern-day Sweden). Today he is remembered as an early astronomer, though in his lifetime, he was also well known as an astrologer and alchemist.

Tycho Brahe was granted an estate on the island of Hven and the funding to build the Uraniborg, an early research institute, where he built large astronomical instruments and took many careful measurements. As an astronomer, Tycho worked to combine what he saw as the geometrical benefits of the Copernican system with the philosophical benefits of the Ptolemaic system into his own model of the universe, the Tychonic system. From 1600 until his death in 1601, he was assisted by Johannes Kepler, who would later use Tycho's astronomical information to develop his own theories of astronomy.

He is credited with the most accurate astronomical observations of his time. The data he generated were used by his assistant Kepler to derive the laws of planetary motion. No one before Tycho had attempted to make so many redundant observations, and the mathematical tools to take advantage of them had not yet been developed. He did what others before him were unable or unwilling to do — to catalogue the planets and stars with enough accuracy so as to determine whether the Ptolemaic or Copernican system was more valid in describing the heavens.

Life

Early years

Tycho Brahe was born Tyge Ottesen Brahe (de Knutstorp), adopting the Latinised form Tycho around age fifteen (sometimes written Tÿcho). He is often misnamed Tycho de Brahe. He was born at his family's ancestral seat of Knutstorp Castle, Denmark to Otte Brahe and Beate Bille. His twin brother died before being baptized. (Tycho wrote a Latin ode (Wittendorf 1994, p. 68) to his dead twin which was printed as his first publication in 1572). He also had two sisters, one older (Kirstine Brahe) and one younger (Sophia Brahe). Otte Brahe, Tycho's father, was a nobleman and an important figure in the Danish King's court. His mother, Beate Bille, also came from an important family that had produced leading churchmen and politicians. In his youth he lived at Hvedborg Manor, Funen, Denmark with his uncle and attended Horne Church in nearby Horne.

Tycho later wrote that when he was around two, his uncle, Danish nobleman Jørgen Brahe, "... without the knowledge of my parents took me away with him while I was in my earliest youth." Apparently this did not lead to any disputes nor did his parents attempt to get him back. Tycho lived with his childless uncle and aunt, Jørgen Brahe and Inger Oxe, in the Tostrup Castle until he was six years old. Around 1552 his uncle was given the command of Vordingborg Castle to which they moved, and where Tycho began a Latin education until he was 12 years old.

On April 19 1559, Tycho began his studies at the University of Copenhagen. There, following the wishes of his uncle, he studied law but also studied a variety of other subjects and became interested in astronomy. It was, however, the eclipse which occurred on August 21 1560, particularly the fact that it had been predicted, that so impressed him that he began to make his own studies of astronomy helped by some of the professors. He purchased an ephemeris and books such as Sacrobosco's Tractatus de Sphaera, Apianus's Cosmographia seu descriptio totius orbis and Regiomontanus's De triangulis omnimodis.

I've studied all available charts of the planets and stars and none of them match the others. There are just as many measurements and methods as there are astronomers and all of them disagree. What's needed is a long term project with the aim of mapping the heavens conducted from a single location over a period of several years. — Tycho Brahe, 1563 (age 17).

Tycho realized that progress in the science of astronomy could be achieved not by occasional haphazard observations, but only by systematic and rigorous observation, night after night, and by using instruments of the highest accuracy obtainable. He was able to improve and enlarge the existing instruments, and construct entirely new ones. Tycho's naked eye measurements of planetary parallax were accurate to the arcminute. His sister, Sophia, assisted Tycho in many of his measurements. These jealously guarded measurements became the possessions of Kepler following his death. Tycho was the last major astronomer to work without the aid of a telescope, soon to be turned toward the sky by Galileo.

While a student, Tycho lost part of his nose in a duel with rapiers with Manderup Parsbjerg, a fellow Danish nobleman. This occurred in the Christmas season of 1566, after a fair amount of drinking, while the just turned 20-year-old Tycho was studying at the University of Rostock in Germany. Attending a dance at a professor's house, he quarreled with Parsbjerg. A subsequent duel (in the dark) resulted in Tycho losing the bridge of his nose. A consequence of this was that Tycho developed an interest in medicine and alchemy. For the rest of his life, he was said to have worn a replacement made of silver and gold blended into a flesh tone, and used an adhesive balm to keep it attached. However, in 1901 Tycho's tomb was opened and his remains were examined by medical experts. The nasal opening of the skull was rimmed with green, a sign of exposure to copper, not silver or gold. Some historians have speculated that he wore a number of different prosthetics for different occasions, noting that a copper nose would have been more comfortable and less heavy than one of precious metals.

Death of his father

His foster father, uncle Jørgen Brahe, died in 1565 of pneumonia after rescuing Frederick II of Denmark from drowning. In April 1567, Tycho returned home from his travels and his father wanted him to take up law, but Tycho was allowed to make trips to Rostock, then on to Augsburg (where he built a great quadrant), Basel, and Freiburg. At the end of 1570 he was informed about his father's ill health, so he returned to Knudstrup, where his father died on May 9 1571. Soon after, his other uncle Steen Bille helped him build an observatory and alchemical laboratory at Herrevad Abbey.

Family life

In 1572, in Knudstrup, Tycho fell in love with Kirsten Jørgensdatter, a commoner whose father, Pastor Jorgen Hansen, was the Lutheran clergyman of Knudstrup's village church. Under Danish law, when a nobleman and a common woman lived together openly as husband and wife, and she wore the keys to the household at her belt like any true wife, their alliance became a binding morganatic marriage after three years. The husband retained his noble status and privileges; the wife remained a commoner. Their children were legitimate in the eyes of the law, but they were commoners like their mother and could not inherit their father's name, coat of arms, or land property. (Skautrup 1941, pp. 24-5)

Kirsten Jørgensdatter gave birth to their first daughter, Kirstine (named after Tycho's late sister who died at 13) on October 12 1573. Together they had eight children, six of whom lived to adulthood. In 1574, they moved to Copenhagen where their daughter Magdalene was born. Kirsten and Tycho lived together for almost thirty years until Tycho's death.

Tycho's Moose

Tycho was said to own one percent of the entire wealth of Denmark at one point in the 1580s and he often held large social gatherings in his castle. He kept a dwarf named Jepp (who Tycho believed was clairvoyant) as a court jester who sat under the table during dinner. Pierre Gassendi wrote that Tycho also had a tame Moose, and that his mentor the Landgraf Wilhelm of Hesse-Kassel asked about an animal faster than a deer. Tycho replied writing there were none, but he could send his tame Moose. When Wilhelm replied he would accept one in exchange for a horse, Tycho replied with the sad news that the Moose just died on a visit to entertain a nobleman at Landskrona. Apparently during dinner the Moose had drunk a lot of beer, fell down the stairs, and died.

Death

Tycho died on October 24, 1601, eleven days after suddenly becoming very ill during a banquet. At the time, it was generally thought that he had strained his bladder as a result of voluntary water retention. Subsequently, a complete cessation of urinary functions, attributed to a blockage or obstruction, manifested itself. Tycho died after suffering for the next week and a half, of what was variously described as intestinal fever or a burst bladder. At the same time, or soon thereafter, a rumour began to make the rounds that Tycho had been poisoned. These rumours were generally dismissed by historians.

But then in the 1990s, modern forensic tests were conducted on some hair samples of Tychos which had not decomposed completely. These tests showed that there was a large relative increase in the concentrations of Mercury 13 hours before Tycho's death. Following this, in a book published in 2004 (Heavenly Intrigue, by Joshua and Anne-Lee Gilder), contemporary and modern theories concerning the cause of Tycho's death were examined and rebutted. The Gilder's asserted, based on all the evidence, that Tycho had indeed died of Mercury poisoning.

Tycho Brahe's body is currently interred in a tomb in the Church of Our Lady in front of Týn near Old Town Square near the Astronomical Clock in Prague.

Scientific achievements

Supernova of 1572

On November 11, 1572, Tycho observed (from Herrevad Abbey) a very bright star which unexpectedly appeared in the constellation Cassiopeia, now named SN 1572. Since it had been maintained since antiquity that the world beyond the orbit of the moon, i.e. that of the fixed stars, was eternal and unchangeable (a fundamental axiom of the Aristotelian world view: celestial immutability), other observers held that the phenomenon was something in the Earth's atmosphere. Tycho, however, observed that the parallax of the object did not change from night to night, suggesting that the object was far away. Tycho argued that a nearby object should appear to shift its position with respect to the background. He published a small book, De Stella Nova (1573), thereby coining the term nova for a "new" star (we now know that Tycho's star in Cassiopeia was a supernova 7500 light years from earth, today known as SN 1572). This discovery was decisive for his choice of astronomy as a profession. Tycho was strongly critical of those who dismissed the implications of the astronomical appearance, writing in the preface to De Stella Nova: "O crassa ingenia. O caecos coeli spectatores" ("Oh thick wits. Oh blind watchers of the sky").

Tycho's discovery was the inspiration for Edgar Allan Poe's poem, Al Aaraaf. In 1998, Sky & Telescope magazine published an article by Donald W. Olson, Marilynn S. Olson and Russell L. Doescher arguing, in part, that Tycho's supernova was also the same "star that's westward from the pole" in Shakespeare's Hamlet.

Great Comet of 1577

In 1577, a brilliant comet appeared in the skies over Europe, exciting much wonder and attention. Tycho's observations of this comet were the most detailed and accurate observations up to that time. Not only did he take repeated position measurements of the object on every day when it was observable, but, in order to better determine its position, he re-determined the celestial coordinates of all of the nearby reference stars as well.

In 1588, Tycho published these observations together with an analysis (and critique) of the cometary observations of others, in a large volume entitled De mundi aetherei recentioribus phaenomenis (Concerning the recent phenomena of the aetherial world). In this book, he showed convincingly that the comet exhibited no diurnal parallax and hence was located beyond the "sphere" of the Moon. Prior to this time, cometary phenomena were thought to be atmospheric in origin. This posed a direct challenge to the Aristotelian view that change in the heavens was the domain of the sub-lunary sphere and that the heavens (the aetherial regions), being perfect, could not undergo and real change.

In addition to his observations on the comet, Tycho for the first time published a description of his cosmological system (the Tychonic system) in this volume.

Tycho's system of cosmology

In this depiction of the Tychonic system, the objects on blue orbits (the moon and the sun) rotate around the earth. The objects on orange orbits (Mercury, Venus, Mars, Jupiter, and Saturn) rotate around the sun. Around all is sphere of fixed stars.

Kepler tried, but was unable, to persuade Tycho to adopt the heliocentric model of the solar system. Tycho believed in a modified geocentric model known as the Tychonic system, for the same reasons that he argued that the supernova of 1572 was not near the Earth. He argued that if the Earth were in motion, then nearby stars should appear to shift their positions with respect to background stars. In fact, this effect of parallax does exist; but it could not be observed with the naked eye, or even with the telescopes of the next two hundred years, because even the nearest stars are much more distant than most astronomers of the time believed possible. The Tychonic system is very similar to the Copernican one, except that it has a static earth instead of a static sun.

In the years following Galileo's observation of the phases of Venus in 1610, which made the Ptolemaic system intractable, the Tychonic system became the major competitor with Copernicanism, and was adopted by the Roman Catholic Church for many years as its official astronomical conception of the universe.

Tycho himself was not a Copernican, but proposed a system in which the Sun orbited the Earth while the other planets orbited the Sun. His system provided a safe position for astronomers who were dissatisfied with older models but were reluctant to accept the Earth's motion. It gained a considerable following after 1616 when Rome decided officially that the heliocentric model was contrary to both philosophy and Scripture, and could be discussed only as a computational convenience that had no connection to fact. His system also offered a major innovation: while both the geocentric model and the heliocentric model as set forth by Copernicus relied on the idea of transparent rotating crystalline spheres to carry the planets in their orbits, Tycho eliminated the spheres entirely.

Uraniborg, Stjerneborg, and Benátky nad Jizerou

Watercolor plan of Uraniborg

King Frederick II of Denmark and Norway, impressed with Tycho's 1572 observations, financed the construction of two observatories for Tycho on the island of Hven in Oresund. These were Uraniborg and Stjerneborg. Uraniborg also had a laboratory for his alchemical experiments.

Because Tycho disagreed with Christian IV, the new king of his country, he left Hven in 1597 and moved to Prague in 1599. Sponsored by Rudolf II, the Holy Roman Emperor, he built a new observatory in a castle in Benátky nad Jizerou, 50 km from Prague, and he worked there for one year. The emperor then had him move back to Prague, where he stayed until his death.

In return for their support, Tycho's duties included preparing astrological charts and predictions for his patrons on events such as births, weather forecasting, and providing astrological interpretations of significant astronomical events such as the comet of 1577 and the supernova of 1572.

Instruments and observational techniques

Mural quadrant (Tycho Brahe 1598)

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Danish stamp of 1946 featuring Tycho Brahe.

Tycho was the preeminent observational astronomer of the pre-telescopic period, and his observations of stellar and planetary positions achieved unparalleled accuracy for their time. For example, Tycho measured Earth's axial tilt as 23 degrees and 31.5 minutes, which he claimed to be more accurate than Copernicus by 3.5 minutes. After his death, his records of the motion of the planet Mars enabled Kepler to discover the laws of planetary motion, which provided powerful support for the Copernican heliocentric theory of the solar system.

He was aware that a star observed near the horizon appears with a greater altitude than the real one, due to atmospheric refraction, and he worked out tables for the correction of this source of error.

To perform the huge number of products needed to produce much of his astronomical data, Tycho relied heavily on the then-new technique of prosthaphaeresis, an algorithm for approximating products based on trigonometric identities that predated logarithms.

Astrology and alchemy

Like the fifteenth century astronomer Regiomontanus, Tycho Brahe appears to have accepted astrological prognostications on the principle that the heavenly bodies undoubtedly influenced (yet did not determine) terrestrial events, but expressed skepticism about the multiplicity of interpretative schemes, and increasingly preferred to work on establishing a sound mathematical astronomy. Two early tracts, one entitled Against Astrologers for Astrology, and one on a new method of dividing the sky into astrological houses, were never published and are unfortunately now lost.

Tycho also worked in the area of weather prediction, produced astrological interpretations of the supernova of 1572 and the comet of 1577, and furnished his patrons Frederick II and Rudolph II with nativities and other predictions (thereby strengthening the ties between patron and client by demonstrating value). An astrological worldview was fundamental to Tycho's entire philosophy of nature. His interest in alchemy, particularly the medical alchemy associated with Paracelsus, was almost as long-standing as his study of astrology and astronomy simultaneously, and Uraniborg was constructed as both observatory and laboratory.

In an introductory oration to the course of lectures he gave in Copenhagen in 1574, Tycho defended astrology on the grounds of correspondences between the heavenly bodies, terrestrial substances (metals, stones etc.) and bodily organs (medical astrology). He was later to emphasise the importance of studying alchemy and astrology together with a pair of emblems bearing the mottoes: Despiciendo suspicio ("By looking down I see upward") and Suspiciendo despicio ("By looking up I see downward"). As several scholars have now argued, Tycho's commitment to a relationship between macrocosm and microcosm even played a role in his rejection of Copernicanism and his construction of a third world-system.

Further reading

Original source material

• Brahe, Tycho. Tychonis Brahe Dani Opera Omnia (in Latin). Vol 1-15. 1913-1929. Edited by I.L.E. Dreyer.
• Astronomiae instauratae mechanica, 1602 edition - Full digital facsimile, Lehigh University.
• Astronomiae instauratae mechanica, 1602 edition - Full digital facsimile, Smithsonian Institution.
• Astronomiae instauratae mechanica, 1598 edition - Full digital facsimile, the Royal Library, Denmark. Includes Danish and English translations.

Biographies and studies

• Christianson, John Robert: On Tycho's Island: Tycho Brahe, science, and culture in the sixteenth century. Cambridge: Cambridge University Press, 2000 ISBN 0-521-65081-X
• Dreyer, J.L.E., Tycho Brahe: a Picture of Scientific Life and Work in the Sixteenth Century
• Ferguson, Kitty: The nobleman and his housedog: Tycho Brahe and Johannes Kepler: the strange partnership that revolutionised science. London : Review, 2002 ISBN 0-7472-7022-8 (published in the US as: Tycho & Kepler: the unlikely partnership that forever changed our understanding of the heavens. New York: Walker, 2002 ISBN 0-8027-1390-4)
• Gilder, Joshua and Gilder, Anne-Lee Heavenly intrigue. New York: Doubleday, 2004 ISBN 0-385-50844-1
• Olson, Donald W.; Olson, Marilynn S.; Doescher, Russell L., "The Stars of Hamlet," Sky & Telescope (November 1998)
• Skautrup, Peter, 1941 Den jyske lov: Text med oversattelse og ordbog. Aarhus: Universitets-forlag.
• Thoren, Victor E.: The Lord of Uraniborg: a biography of Tycho Brahe. Cambridge: Cambridge University Press, 1990 ISBN 0-521-35158-8
• Thoren, Victor E.: "Tycho Brahe" in Planetary Astronomy from the Rennaissance to the rise of astrophysics, volume 2A (Cambridge University Press, 1989)
• Thoren, Victor E. and Hetherington, Norriss S., "Tycho Brahe" and "Brahe's Cosmology", in the Encyclopedia of Cosmology (Garland Publishing Company, New York, 1993)
• Wittendorff, ALex. 1994. Tyge Brahe. Copenhagen: G. E. C. Gad.

External links

• Brahe, Tycho MacTutor History of Mathematics
• Tycho Brahe pages by Adam Mosley at Starry Messenger: An Electronic History of Astronomy, University of Cambridge
• Brahe Bio