Tycho Brahe

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Tycho Brahe

1546-1601

Astronomer

Beginnings. Born into Denmark’s high nobility, Tycho Brahe opted to become a prince of scientific researchers instead of pursuing a military or diplomatic career, as befit his aristocratic heritage. Like many of his noble peers, he was tutored in Latin at home and traveled widely in his youth, visiting various European universities—enrolling at Copenhagen, Leipzig, and Rostock—and making the acquaintance of natural philosophers and noblemen wherever he went. Astronomy captured his interest early, and he bought books and instruments for private study of the subject. When he realized that his observations in Leipzig of the conjunction of Jupiter and Saturn did not agree with the date predicted by the astronomical tables then in use, he determined to reform astronomy and bring it up to date with new observations. Such tables were of great importance in Renaissance Europe because the accuracy of astrological prediction depended on them, and such predictions affected medical diagnostics and therapy as well as providing the widely popular horoscopes that guided kings and commoners alike. The needs of state, in particular, made astrology a suitable science for an aristocrat to dabble in, as was alchemy, which Brahe also studied in Germany. When his father’s death forced him to return to Denmark and settle his inheritance, Brahe sold his share of the family estate to his brother and moved into the former Herrevad Abbey, which was in the possession of his aunt and uncle. There he built a laboratory and set about what would become his lifelong pursuit of both alchemy and astronomy.

Birth of a Star. In fact, Brahe viewed alchemy and astrology as two aspects of a single science. He believed that there was a sympathetic correspondence between the stars and planets, metals, minerals, stones, and plants, and also the organs of the human body. The operations of the cosmos could therefore be studied in the observatory, by means of what he called “celestial astronomy,” or in the laboratory, by “terrestrial astronomy,” which referred to alchemy. Brahe recalled that he was returning to the main house from his laboratory at Herrevad in 1572 when he first noticed a new star in the sky, a phenomenon that is still called a nova (new). Such a thing was unknown to Europeans and was presumed not to be possible in the celestial realm, since the region of the stars and planets was generally thought to be perfect and incapable of any novelty or decay. Accordingly, astronomers throughout Europe were eager to observe the new star and publish their interpretations of what it might be and what its appearance portended. Brahe carefully observed the new star and determined it to be a long distance from the Earth, and therefore not simply an atmospheric phenomenon of some sort, as Aristotle had taught.

Uraniborg. Brahe published his findings and interpretations in De nova stella (The New Star) in 1573. The small volume demonstrated that he was a competent and well-educated astronomer, bringing him to the attention of Europe’s scholars and encouraging the king of Denmark to offer him a feudal endowment if he would build a research facility on royal land and reside in Denmark as an aristocrat in service to the crown. This position was the kind that suited a member of one of Denmark’s most powerful families. The result was Uraniborg, a Renaissance villa that Brahe erected on the island of Hven, within sight of Copenhagen and the royal fortresses of Kronborg and Landskrona, between which every ship entering the Baltic Sea from the Atlantic must pass. The location was in many respects ideal: it was central to the kingdom, within easy reach of the capital and the court, and yet isolated by water, providing a measure of privacy and undisturbed study. The island rises abruptly out of the Danish sound that today separates Sweden from Denmark, and often enjoys clear weather when the nearby shores are clouded over, making it a suitable location for an observatory.

Laboratory. Uraniborg was not expansive by Danish aristocratic standards, but expensive to build and maintain. It featured the latest Dutch and Italianate architectural styles, statuary, Dutch paintings, and a stone-faced earthen perimeter wall with gate houses, surrounded by an elaborate garden with gazebos and walkways. Uraniborg was more than an aristocrat’s house, though. Its clever design also accommodated a library, where the research staff could gather, sleeping rooms for his assistants, and observation decks with removable roof sections on the north and south ends of the second story. On these decks Brahe placed various devices for measuring the angles between stars and planets, which enabled him to record their positions. In the basement he built a well-equipped alchemical laboratory, which in complexity rivaled those owned by kings and princes elsewhere in Europe. Although he claimed to have spent an equal amount of time and money on alchemical research, no records of his work in that area have survived, except for a couple of recipes for medical elixirs. Nevertheless, reports from visitors to the island support Brahe’s description of an elaborate facility with many kinds of furnaces and condensers.

Accurate Data. As his need for greater astronomical precision developed, he constructed another observatory nearby, one that was dug into the ground in order to provide a protected place to mount even larger instruments out of the wind, which vibrated them and introduced errors. Several large observation pits, with stable stone foundations on which to set various enormous quadrants and armillary astrolabes, had removable covers to shield them from the rain and permit sighting of the major celestial phenomena. With the best of these instruments, Brahe was able to double the accuracy of previous astronomical data. He commemorated the irony of observing the heavens from underground in a Latin poem, one of many that revealed his training as a Renaissance scholar.

Quest for Perfection. Construction of Uraniborg commenced in 1576 and was largely completed by 1580, but Brahe was an incessant builder and tireless researcher, always trying to improve his research methods and tinkering with the design of his villa and his instruments. Besides the underground observatory, which he intended to connect to Uraniborg by tunnel, he built a printing house and a paper mill, so that he could publish his work on location. The mill was water powered, but since there was no sufficient stream of water on Hven, Brahe created a system of fish ponds that acted as reservoirs to collect rainwater to drive the water wheel. He also built a workshop and a glassworks to supply his instruments, alchemical glassware, and household needs.

Published Work. Brahe accumulated an immense amount of observational data while resident on Hven, which was eventually published as the Rudolphine astronomical tables in the next century. Besides positional data, from which he hoped to construct a new theory of planetary motion, he made an important observation on a comet in 1577, which proved that it was a celestial and not an atmospheric phenomenon, as the Aristotelians believed. Tycho’s realization that comets crossed through the orbs that were supposed to carry the Sun, Moon, and planets around Earth suggested to him that the celestial spheres were not substantial enough to hinder penetration. On this basis, he created his own planetary model, in which the Sun and Moon revolved around Earth, as was the case in ancient astronomy, but the other planets revolved around the Sun, as in the Copernican system. Brahe published the details of this new model in 1588 and it became quite influential in the seventeenth century.

Rudolf II. That same year King Frederik of Denmark, Brahe’s patron and friend, died and was succeeded by his son Christian IV. For various reasons, he fell out of favor with the new king and his advisers, who began to revoke his royal endowments. The result was that Brahe abandoned Uraniborg in 1597 and eventually secured an appointment at the court of Rudolf II, the Holy Roman Emperor, where he hoped to reproduce the research facilities he had developed in Denmark. To that end, he moved his household into Benatky Castle outside Prague, the imperial capital, shipped his instruments from Denmark, build a new observatory and laboratory, and continued his work. To help him with the tedious mathematical work of correlating observations with theory, Brahe recruited a German mathematician named Johannes Kepler. When Brahe died in 1601, Kepler took possession of the tomes of data that Brahe and his students had produced over the course of three decades and used them to establish a brand new theory: that all planets—including the Earth—traversed elliptical orbital paths around the Sun.

Legacy. Brahe’s many-sided research effort reflected a complex Renaissance view of the cosmos and a commitment to understanding it through systematic study. Besides astronomy and alchemy, he also kept a meteorological record, with which he hoped to grasp the relationship between astrology and weather conditions, he wrote Latin poetry, and began to make accurate maps of Hven and its surroundings. All of these activities were woven together into life at Uraniborg, which is regarded as Europe’s first dedicated research institute. Uraniborg itself fell into ruin in the decades after Brahe left it, cannibalized for building material for local projects. Brahe’s program, however, lived on in Copenhagen, where the king established a royal observatory where his student Christian Sørensen (Longomontanus) was installed as royal astronomer, and a royal laboratory, where a Paracelsian physician was hired to distill elixirs and make other chemical medicines.