GALILEO,

born Feb. 15, 1564, Pisa died Jan. 8, 1642, Arcetri, near Florence in full Galileo Galilei Italian mathematician, astronomer, and physicist, considered a founder of the experimental method. Galileothe son of Vincenzo Galilei, a musicianwas educated at a monastery near Florence before studying medicine at the University of Pisa and mathematics with a private tutor. After completing a treatise on the centre of gravity in solids, he became lecturer in mathematics at the university at the age of 25. Later he went to the University of Padua as a professor of mathematics. The story of his dropping weights from the Leaning Tower of Pisa has no basis in fact. A substantial part of Galileo's work is related to mechanics, and he was the first to apply mathematics to its analysis. He suggested the use of pendulums for clocks and proposed the law of uniform acceleration for falling bodies. Galileo developed the astronomical telescope, with which he discovered craters on the Moon, sunspots, phases of Venus, and the satellites of Jupiter. He showed that the Milky Way is composed of stars. His astronomical observations led him to espouse the Copernican theory that the planets revolve around the Sun. This conflicted with the teachings of the Roman Catholic church, however, and Galileo was forced to recant his findings and was placed under house arrest for the final eight years of his life for having held and taught Copernican doctrine. In 1992 the church formally acknowledged its error in condemning Galileo. Galileo's major works were Dialogue Concerning the Two Chief World SystemsPtolemaic and Copernican (1632) and Dialogue Concerning Two New Sciences (1638). born Feb. 15, 1564, Pisa died Jan. 8, 1642, Arcetri, near Florence Galileo, oil painting by Justus Sustermans, c. 1637; in the Uffizi Gallery, Florence. in full Galileo Galilei 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. Additional reading The standard edition of Galileo's works is Le opere di Galileo Galilei, 20 vol. in 21, ed. by Antonio Favaro (18901909, reissued 1968). There are now English editions of all Galileo's works published during his lifetime. Galileo Against the Philosophers in His Dialogue of Cecco di Ronchitti (1605) and Considerations of Alimberto Mauri (1606), trans. by Stillman Drake (1976), contains two early dialogues thought to have been written by Galileo. His defense of the priority of his military compass appears as Operations of the Geometric and Military Compass, 1606, trans. by Stillman Drake (1978). There are several English translations of Sidereus Nuncius (1610): The Sidereal Messenger of Galileo Galilei and a Part of the Preface to Kepler's Dioptrics Containing the Original Account of Galileo's Astronomical Discoveries, trans. by Edward Stafford Carlos (1880, reprinted 1959); Sidereus Nuncius; or, The Sidereal Messenger, trans. by Albert Van Helden (1989); and Stillman Drake, Telescopes, Tides, and Tactics: A Galilean Dialogue About the Starry Messenger and Systems of the World (1983), which contains a complete translation interspersed in the dialogue. Discorso . . . intorno alle cose, che stanno in s l'acqua, che in quella si muovono (1612) appears in English as Discourse on Bodies in Water, trans. by Thomas Salusbury and ed. by Stillman Drake (1960); and is interspersed in a dialogue in Stillman Drake, Cause, Experiment, and Science: A Galilean Dialogue, Incorporating a New English Translation of Galileo's Bodies That Stay Atop Water, or Move in It (1981). Galileo's letter to the grand duchess Christina on the relationship of science to religion, written in 1615, was published in Latin in Strasbourg in 1636 without Galileo's permission; English translations are Letter to Madame Christina . . . , in Discoveries and Opinions of Galileo, trans. by Stillman Drake (1957, reissued 1990), pp. 175216, which also includes abridged translations of Sidereus Nuncius, the letters on sunspots (Istoria e dimostrazioni intorno alle macchie solari e loro accidenti, 1613), and Il saggiatore; and Galileo's Letter to the Grand Duchess Christina (1615), in Maurice A. Finocchiaro (ed. and trans.), The Galileo Affair: A Documentary History (1989), pp. 87118, which also includes the translated documents of Galileo's trial. A translation of Il saggiatore (1623) is The Assayer, in The Controversy on the Comets of 1618, trans. by Stillman Drake and C.D. O'Malley (1960), pp. 151336. The standard translation of Dialogo sopra i due massimi sistemi del mondo tolemaico, e copernicano (1632) is Dialogue Concerning the Two Chief World Systems, Ptolemaic & Copernican, trans. by Stillman Drake, 2nd ed. (1967). Galileo's Discorsi e dimostrazioni matematiche, intorno due nuove scienze . . . (1638) appears as Dialogues Concerning Two New Sciences, trans. by Henry Crew and Alfonso de Salvio (1914, reissued 1968); and Two New Sciences, trans. by Stillman Drake, rev. ed. (1989).Of Galileo's works that remained unpublished during his lifetime, a number have been published in English translation. The early tracts on Aristotelian philosophy and scientific method are published and commented on in William A. Wallace, Galileo and His Sources: The Heritage of the Collegio Romano in Galileo's Science (1984), and Galileo's Logic of Discovery and Proof: The Background, Content, and Use of His Appropriated Treatises on Aristotle's Posterior Analytics (1992); and in William A. Wallace (trans.), Galileo's Early Notebooks: The Physical Questions (1977), and Galileo's Logical Treatises: A Translation, with Notes and Commentary, of His Appropriated Latin Questions on Aristotle's Posterior Analytics (1992). The early notebooks on motion have been published as On Motion, and On Mechanics, trans. by I.E. Drabkin and Stillman Drake (1960); and selections appear in Mechanics in Sixteenth-Century Italy, trans. by Stillman Drake and I.E. Drabkin (1969). Galileo's cryptic notes on his experiments on motion contained in vol. 72 of the Galileo manuscripts but not published in the Opere have been published in facsimile: Galileo's Notes on Motion, arranged by Stillman Drake (1979). The correspondence between Galileo and one of his daughters is available in Mary Allan-Olney (compiler), The Private Life of Galileo: Compiled Principally from his Correspondence and That of His Eldest Daughter, Sister Maria Celeste (1870).Several biographies of Galileo have been written by Stillman Drake: Galileo at Work: His Scientific Biography (1978, reissued 1995), Galileo: Pioneer Scientist (1990), and Galileo (1980). James Reston, Jr., Galileo (1994), is a well-documented popular biography. Portraits and other depictions of Galileo can be found in J.J. Fahie, Memorials of Galileo Galilei, 15641642 (1929).Studies of various aspects of Galileo's life and career include Lane Cooper, Aristotle, Galileo, and the Tower of Pisa (1935, reissued 1972); Erwin Panofsky, Galileo as a Critic of the Arts (1954); Pasquale M. d'Elia, Galileo in China: Relations Through the Roman College Between Galileo and the Jesuit Scientist-Missionaries (16101640) (1960; originally published in Italian, 1947); Antonio Favaro, Galileo Galilei e lo studio di Padova, 2 vol. (1883, reissued 1966), and Galileo Galilei a Padova: ricerche e scoperte, insegnamento, scolari (1968); Carlo L. Golino (ed.), Galileo Reappraised (1966), a collection of papers delivered at a commemorative conference in 1965; Ernan McMullin (ed.), Galileo, Man of Science (1968, reissued 1988), consisting chiefly of papers presented at the Galileo Quatercentenary Congress in 1964; Stillman Drake, Galileo Studies: Personality, Tradition, and Revolution (1970); William R. Shea, Galileo's Intellectual Revolution: Middle Period, 16101632, 2nd ed. (1977); Dudley Shapere, Galileo: A Philosophical Study (1974); Maurice Clavelin, The Natural Philosophy of Galileo: Essay on the Origins and Formatino of Classical Mechanics (1974; originally published in French, 1968); Alexandre Koyr, Galileo Studies (1978; originally published in French, 3 vol., 1939); Maurice A. Finocchiaro, Galileo and the Art of Reasoning: Rhetorical Foundations of Logic and Scientific Method (1980); Silvio A. Bedini, The Pulse of Time: Galileo Galilei, the Determination of Longitude, and the Pendulum Clock (1991); Michael Segre, In the Wake of Galileo (1991); Victor Coelho (ed.), Music and Science in the Age of Galileo (1992); Joseph C. Pitt, Galileo, Human Knowledge, and the Book of Nature: Method Replaces Metaphysics (1992); Mario Biagioli, Galileo, Courtier: The Practice of Science in the Culture of Absolutism (1993); Jean Dietz Moss, Novelties in the Heavens: Rhetoric and Science in the Copernican Controversy (1993); and Cesare S. Maffioli, Out of Galileo: The Science of Waters, 16281718 (1994).Works specifically treating Galileo and the Roman Catholic church include Karl von Gebler, Galileo Galilei and the Roman Curia (1879, reprinted 1977; originally published in German, 2 vol., 187677); Giorgio de Santillana, The Crime of Galileo (1955, reprinted 1981); Jerome J. Langford, Galileo, Science, and the Church, 3rd ed. (1992); Pietro Redondi, Galileo Heretic (1987; originally published in Italian, 1983); Richard S. Westfall, Essays on the Trial of Galileo (1989); Richard J. Blackwell, Galileo, Bellarmine, and the Bible (1991); Rivka Feldhay, Galileo and the Church: Political Inquisition or Critical Dialogue? (1995); and Annibale Fantoli, Galileo: For Copernicanism and for the Church, 2nd ed., rev. and corrected (1996; originally published in Italian, 1993). Albert Van Helden