The 100 Most Influential Scientists of All Time (8 page)

The new star in the constellation Cassiopeia caused Tycho to dedicate himself to astronomy; one immediate decision was to establish a large observatory for regular observations of celestial events. His plan to establish this observatory in Germany prompted King Frederick II to keep him in Denmark by granting him title in 1576 to the island of Ven (formerly Hven), in the middle of The Sound and about halfway between Copenhagen and Helsingør, together with financial support for the observatory and laboratory buildings. Tycho called the observatory Uraniborg, after Urania, the Muse of
astronomy. Surrounded by scholars and visited by learned travelers from all over Europe, Tycho and his assistants collected observations and substantially corrected nearly every known astronomical record.

Tycho was an artist as well as a scientist and craftsman, and everything he undertook or surrounded himself with had to be innovative and beautiful. He established a printing shop to produce and bind his manuscripts in his own way, he imported Augsburg craftsmen to construct the finest astronomical instruments, he induced Italian and Dutch artists and architects to design and decorate his observatory, and he invented a pressure system to provide the then uncommon convenience of sanitary lavatory facilities. Uraniborg fulfilled the hopes of Tycho's king and friend, Frederick II, that it would become the centre of astronomical study and discovery in northern Europe. But Frederick died in 1588, and under his son, Christian IV, Tycho's influence dwindled; most of his income was stopped, partly because of the increasing needs of the state for money. Spoiled by Frederick, however, Tycho had become both unreasonably demanding of more money and less inclined to carry out the civic duties required by his income from state lands.

At odds with the three great powers—king, church, and nobility—Tycho left Ven in 1597, and, after short stays at Rostock and at Wandsbek, near Hamburg, he settled in Prague in 1599 under the patronage of Emperor Rudolf II, who also in later years supported the astronomer Johannes Kepler.

The major portion of Tycho's lifework—making and recording accurate astronomical observations—had already been done at Uraniborg. To his earlier observations, particularly his proof that the nova of 1572 was a star, he added a comprehensive study of the solar system and his proof that the orbit of the comet of 1577 lay beyond the Moon.
He proposed a modified Copernican system in which the planets revolved around the Sun, which in turn moved around the stationary Earth. What Tycho accomplished, using only his simple instruments and practical talents, remains an outstanding accomplishment of the Renaissance.

Tycho attempted to continue his observations at Prague with the few instruments he had salvaged from Uraniborg, but the spirit was not there, and he died in 1601, leaving all his observational data to Kepler, his pupil and assistant in the final years. With these data Kepler laid the groundwork for the work of Sir Isaac Newton.

(b. 1548, Nola, near Naples—d. Feb. 17, 1600, Rome)

G
iordano Bruno was an Italian philosopher, astronomer, mathematician, and occultist whose theories anticipated modern science. The most notable of these were his theories of the infinite universe and the multiplicity of worlds, in which he rejected the traditional geocentric astronomy and intuitively went beyond the Copernican heliocentric theory, which still maintained a finite universe with a sphere of fixed stars. Bruno is, perhaps, chiefly remembered for the tragic death he suffered at the stake because of the tenacity with which he maintained his unorthodox ideas at a time when both the Roman Catholic and the Reformed churches were reaffirming rigid Aristotelian and Scholastic principles in their struggle for the evangelization of Europe.

In the spring of 1583 Bruno moved from Paris to London and was soon attracted to Oxford, where, during the summer, he started a series of lectures in which he expounded
the Copernican theory maintaining the reality of the movement of the Earth. In February 1584 he was invited to discuss his theory of the movement of the Earth with some doctors from the University of Oxford. However, the discussion degenerated into a quarrel, and a few days later he started writing his Italian dialogues, which constitute the first systematic exposition of his philosophy. There are six dialogues, three of which are cosmological—on the theory of the universe.

In the
Cena de le Ceneri
(1584; “The Ash Wednesday Supper”), he not only reaffirmed the reality of the heliocentric theory but also suggested that the universe is infinite, constituted of innumerable worlds substantially similar to those of the solar system. In the same dialogue he anticipated his fellow Italian astronomer Galileo Galilei by maintaining that the Bible should be followed for its moral teaching but not for its astronomical implications. He also strongly criticized the manners of English society and the pedantry of the Oxford doctors.

In the
De la causa, principio e uno
(1584;
Concerning the Cause, Principle, and One
) he elaborated the physical theory on which his conception of the universe was based: “form” and “matter” are intimately united and constitute the “one.” Thus, the traditional dualism of the Aristotelian physics was reduced by him to a monistic conception of the world, implying the basic unity of all substances and the coincidence of opposites in the infinite unity of Being.

In the
De l'infinito universo e mondi
(1584;
On the Infinite Universe and Worlds
), he developed his cosmological theory by systematically criticizing Aristotelian physics; he also formulated his Averroistic view of the relation between philosophy and religion, according to which religion is considered as a means to instruct and govern ignorant people, philosophy as the discipline of the elect who are able to behave themselves and govern others.

In October 1585 Bruno returned to Paris, but found himself at odds with the political climate there. As a result, he went to Germany, where he wandered from one university city to another, lecturing and publishing a variety of minor works, including the
Articuli centum et sexaginta
(1588; “160 Articles”) against contemporary mathematicians and philosophers, in which he expounded his conception of religion—a theory of the peaceful coexistence of all religions based upon mutual understanding and the freedom of reciprocal discussion. At Helmstedt, however, in January 1589 he was excommunicated by the local Lutheran Church. He remained in Helmstedt until the spring, completing works on natural and mathematical magic (posthumously published) and working on three Latin poems—
De triplici minimo et mensura
(“On the Threefold Minimum and Measure”),
De monade, numero et figura
(“On the Monad, Number, and Figure”), and
De immenso, innumerabilibus et infigurabilibus
(“On the Immeasurable and Innumerable”)—which reelaborated the theories expounded in the Italian dialogues and developed Bruno's concept of an atomic basis of matter and being.

To publish these, he went in 1590 to Frankfurt am Main, where the senate rejected his application to stay. Nevertheless, he took up residence in the Carmelite convent, lecturing to Protestant doctors and acquiring a reputation of being a “universal man” who, the Prior thought, “did not possess a trace of religion” and who “was chiefly occupied in writing and in the vain and chimerical imagining of novelties.”

In August 1591, at the invitation of the Venetian patrician Giovanni Mocenigo, Bruno made the fatal move
of returning to Italy. During the late summer of 1591, he composed the
Praelectiones geometricae
(“Lectures on Geometry”) and
Ars deformationum
(“Art of Deformation”). In Venice, as the guest of Mocenigo, Bruno took part in the discussions of progressive Venetian aristocrats who, like Bruno, favoured philosophical investigation irrespective of its theological implications. Bruno's liberty came to an end when Mocenigo—disappointed by his private lessons from Bruno on the art of memory and resentful of Bruno's intention to go back to Frankfurt to have a new work published—denounced him to the Venetian Inquisition in May 1592 for his heretical theories. Bruno was arrested and tried. He defended himself by admitting minor theological errors, emphasizing, however, the philosophical rather than the theological character of his basic tenets. The Roman Inquisition demanded his extradition, and on Jan. 27, 1593, Bruno entered the jail of the Roman palace of the Sant'Uffizio (Holy Office).

During the seven-year Roman period of the trial, Bruno at first developed his previous defensive line, disclaiming any particular interest in theological matters and reaffirming the philosophical character of his speculation. This distinction did not satisfy the inquisitors, who demanded an unconditional retraction of his theories. Bruno then made a desperate attempt to demonstrate that his views were not incompatible with the Christian conception of God and creation. The inquisitors rejected his arguments and pressed him for a formal retraction. Bruno finally declared that he had nothing to retract and that he did not even know what he was expected to retract. At that point, Pope Clement VIII ordered that he be sentenced as an impenitent and pertinacious heretic. On Feb. 8, 1600, when the death sentence was formally read to him, he addressed his judges, saying, “Perhaps your fear in passing judgment on me is greater than mine in
receiving it.” Not long after, he was brought to the Campo de' Fiori, his tongue in a gag, and burned alive.

Bruno's theories influenced 17th-century scientific and philosophical thought and, since the 18th century, have been absorbed by many modern philosophers. As a symbol of the freedom of thought, he inspired the European liberal movements of the 19th century, particularly the Italian Risorgimento (the movement for national political unity). Because of the variety of his interests, modern scholars are divided as to the chief significance of his work. Bruno's cosmological vision certainly anticipates some fundamental aspects of the modern conception of the universe. His ethical ideas, in contrast with religious ascetical ethics, appeal to modern humanistic activism, and his ideal of religious and philosophical tolerance has influenced liberal thinkers. On the other hand, his emphasis on the magical and the occult has been the source of criticism as has his impetuous personality. Bruno stands, however, as one of the important figures in the history of Western thought, a precursor of modern civilization.

(b. Feb. 15, 1564, Pisa [Italy]—d. Jan. 8, 1642, Arcetri, near Florence)

G
alileo Galilei was an Italian natural philosopher, astronomer, and mathematician who made fundamental contributions to the sciences of motion, astronomy, and strength of materials and to the development of the scientific method. His formulation of (circular) inertia, the law of falling bodies, and parabolic trajectories marked the beginning of a fundamental change in the study of motion. His insistence that the book of nature was
written in the language of mathematics changed natural philosophy from a verbal, qualitative account to a mathematical one in which experimentation became a recognized method for discovering the facts of nature. Finally, his discoveries with the telescope revolutionized astronomy and paved the way for the acceptance of the Copernican heliocentric system, but his advocacy of that system eventually resulted in an Inquisition process against him.

In the spring of 1609 Galileo heard that in the Netherlands an instrument had been invented that showed distant things as though they were nearby. By trial and error, he quickly figured out the secret of the invention and made his own three-powered spyglass from lenses for sale in spectacle makers' shops. Others had done the same; what set Galileo apart was that he quickly figured out how to improve the instrument, taught himself the art of lens grinding, and produced increasingly powerful telescopes.

In the fall of 1609 Galileo began observing the heavens with instruments that magnified up to 20 times. In December he drew the Moon's phases as seen through the telescope, showing that the Moon's surface is not smooth, as had been thought, but is rough and uneven. In January 1610 he discovered four moons revolving around Jupiter. He also found that the telescope showed many more stars than are visible with the naked eye. These discoveries were earthshaking, and Galileo quickly produced a little book,
Sidereus Nuncius
(
The Sidereal Messenger
), in which he described them. He dedicated the book to Cosimo II de Medici (1590–1621), the grand duke of his native Tuscany, whom he had tutored in mathematics for several summers, and he named the moons of Jupiter after the Medici family: the Sidera Medicea, or “Medicean Stars.”