Tuesday, March 20, 2012

Tycho Brahe (1546-1601): The Noble Dane

by G. Jack Urso

Early Years

Fig. 1: Tycho Brahe.
Tycho Brahe was born in Skane, then in Denmark and now a part of Sweden. The eldest son of parents with a noble heritage, he was brought up by his paternal uncle, Jörgen Brahe. Jörgen was better off financially then his brother and provided for his nephew by sponsoring his education and providing him with an inheritance. Brahe attended the Universities of Copenhagen and Leipzig, as well as the Universities of Wittenberg, Rostock, and Basel. It was during this time that he began his studies in alchemy and astronomy. A quick-tempered young man, Brahe lost his nose in a sword duel with another student in Wittenberg in 1566. Thereafter, he wore a metal nose as a replacement (Van Helden). He is noted to history for his adherence to a geocentric model of the universe despite the overwhelming evidence provided by Copernicus for the heliocentric model.

De Nova Stella 

Brahe's first published work is De Nova Stella (The New Star), printed in Copenhagen, 1573, details his observations of a star that went nova in the constellation of Cassiopeia and first observed on November 11, 1572. The sudden manifestation of what appeared to be a new star demanded explanation. Rumors, inaccurate observations, and mistaken deductions were freely tossed about in the search for an answer.  Brahe, in an effort to set the record straight, decided to publish his own findings (Dreyer 43).  

Brahe made highly accurate observations and calculations regarding the star's magnitude, position, distance and color. Still under the sway of the Aristotelian-Ptolemic idea that the planets and stars were somehow "fixed" to a crystalline celestial sphere, he put the location of the star on the celestial sphere of fixed stars (Dreyer 48). He was among of the last die-hard adherents of this ancient idea, which slowly phased out of mainstream scientific thought between 1575 and 1625. Brahe also spends part of the book discussing the astrological implications of the new star, an illustration that even among the most noted scholars of the Sixteenth century, astronomy and astrology were still linked (Van Helden).  

As previously noted, Brahe did not accept the Copernican view of a heliocentric universe. Why then should we consider his work worthy of academic study? Brahe's passion was in accurate and detailed observations during a time before the invention of the telescope. Although he never accepted the heliocentric model, its proof would be built on detailed, quantifiable facts, some of which Brahe would provide himself through his own observations. 

Despite his intellect, Brahe was still mired in the pseudo-science of the Catholic Church that then relied on a literal interpretation of scripture. Brahe could not reconcile a moving Earth with biblical texts. In his view, Copernicus had merely used his "trigonometry" to show that it was possible to calculate planetary motions without having the Earth as a fixed center-point. In an extraordinary effort involving decades of nightly observations Brahe wrote his greatest work, Introduction to the New Astronomy. Never quite finished, the work can be viewed as a transitional work between the old Ptolemic view of the universe and the new Copernican world-view (Dreyer 175, 178, 181).  

A Stare-Way to Heaven

Fig. 2: Brahe's observatory at Uraniberg.
In 1576, Danish King Fredrick II presented Brahe with title to the island of Hveen in recognition of Brahe's work. The king made Brahe into a sort of feudal lord of the manor, a role perfectly suited for an astronomer of noble heritage. Here, Brahe constructed an observatory of his own design that would be regarded as the best in Europe. In a time before the telescope, Brahe, like Copernicus, used his eye, astrolabes, sextants and other navigational aides as his tools of observation. He designed his observatory, Uraniberg, in alignment with the paths of the various planets across the night sky to maximize his observations in the time before telescopes. One tribute to Brahe's intelligence and skill is that the accuracy of his observations often exceeded the design limitations of his instruments (Dreyer 86-87, 328). 

Fig. 3: Drawing of a
sextant used by Brahe.
Brahe's research done at Uraniberg contributed towards his publications De Mundi Aetherei Recentioribus Phaenomenis (Concerning the New Phenomena in the Ethereal World-Uraniburg, 1588), Astronomiae Instauratae Mechanica (Instruments for the Restored Astronomy-Wandsbeck, 1598), and Astronomiae Instauratae Progymnasmata (Introductory Exercises Toward a Restored Astronomy-Prague, 1602) (Van Helden). In Astronomiae Instauratae Mechanica, Brahe leaves valuable details regarding his instruments and methods of observation. The quest for ever more reliable observations led him to construct large sextants and quadrants as well as several clocks, whose reliability he was never satisfied with (Brahe 8-9). However, it is with his last work, Astronomiae Instauratae Progymnasmata (commonly known as The New Astronomy) that the Copernican Revolution took its next step. 

Restoring Astronomy      

Fig. 4: The Tychonic
Geocentric Universe.
In Introductory Exercises Toward a Restored Astronomy, Brahe works out a new geocentric model of the universe. In the Ptolemic model the Sun and the planets each orbited the Earth attached to their own celestial sphere. Observations by both Brahe and Copernicus showed problems with that model after accurate calculations of the planets' orbits were made. Copernicus established the theory that all the planets revolved around the sun as his response to this problem. Brahe, who could not accept a heliocentric view of the universe, resolved the problems, in his own mind, by creating the Tychonic geocentric model of the universe (Brahe 168-169). In this version, Brahe compromises between the two competing world-views; the Earth is still the center of the universe and the Sun orbits the Earth, but the planets and comets orbit the Sun. This way, Brahe could explain the motions of the planets within a geocentric model. 

Brahe's contributions to the scientific tradition include a greater emphasis on accuracy in the instruments and the observations of astronomers. He introduced transverse divisions between graduated scales on scientific instruments and improvements to the sighting mechanisms (Brahe 331-332) and left a voluminous amount of astronomical observations and calculations that would serve as raw data for generations of astronomers. Tycho Brahe's assistant, Johannes Kepler, would build on this data and make his own contribution to the Copernican Revolution. 

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Works Cited 

Brahe, Tycho. Description of His Instruments and Scientific Work as
        Given in Astronomiae Instrautae Mechanica. Trans., Eds. Hans
        Ræder, Elis and Bengt Strömgren. Copenhagen: Bianco Lunos
        Bogtrykkeri, 1946. Print. 

Dreyer, J.L.E., Ph.D. Tycho Brahe: A Picture of Scientific Life and
        Work in the Sixteenth Century. New York: Dover Publications,
        Inc., 1963. Print. 

Van Helden, Albert. Tycho Brahe. The Galileo Project. Rice
      University, 1995. Web. 16 Nov. 2000. <http://es.rice.edu/
      ES/humsoc/Galileo/ People/tycho_brahe.html>.

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