Galileo Galilei

Born
15 February 1564
Pisa, Duchy of Florence
Died
8 January 1642 (aged 77)
Arcetri, Grand Duchy of Tuscany, Italy
Residence
Grand Duchy of Tuscany
Nationality
Italian
Alma mater
University of Pisa 1580–1585 (no degree)
Known for
Kinematics
Dynamics
Telescopic observational astronomy
Heliocentrism
Scientific career
Fields
Astronomy, physics, engineering, natural philosophy, mathematics
Institutions
University of Pisa 1589–1592
University of Padua 1592–1610
Patrons
Cardinal del Monte
Fra Paolo Sarpi
Prince Federico Cesi
Cosimo II de Medici
Ferdinando II de Medici
Maffeo Barberini
Academic advisors
Ostilio Ricci[1]
Notable students
Benedetto Castelli
Mario Guiducci
Vincenzo Viviani[2]
Signature
Galileo Galilei Signature 2.svg
Notes
His father was the musician Vincenzo Galilei. Galileo Galilei's mistress Marina Gamba (1570 – 21 August 1612?) bore him two daughters (Maria Celeste (Virginia, 1600–1634) and Livia (1601–1659), both of whom became nuns), and a son, Vincenzo (1606–1649), a lutenist.
Galileo studied speed and velocity, gravity and free fall, the principle of relativity, inertia, projectile motion and also worked in applied science and technology, describing the properties of pendulums and "hydrostatic balances", inventing the thermoscope and various military compasses, and using the telescope for scientific observations of celestial objects. His contributions to observational astronomy include the telescopic confirmation of the phases of Venus, the observation of the four largest satellites of Jupiter, the observation of Saturn's rings, and the analysis of sunspots.

Galileo's championing of heliocentrism and Copernicanism was controversial during his lifetime, when most subscribed to geocentric models such as the Tychonic system.[11] He met with opposition from astronomers, who doubted heliocentrism because of the absence of an observed stellar parallax.[11] The matter was investigated by the Roman Inquisition in 1615, which concluded that heliocentrism was "foolish and absurd in philosophy, and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture".[11][12][13] Galileo later defended his views in Dialogue Concerning the Two Chief World Systems (1632), which appeared to attack Pope Urban VIII and thus alienated him and the Jesuits, who had both supported Galileo up until this point.[11] He was tried by the Inquisition, found "vehemently suspect of heresy", and forced to recant. He spent the rest of his life under house arrest.[14][15] While under house arrest, he wrote Two New Sciences, in which he summarized work he had done some forty years earlier on the two sciences now called kinematics and strength of materials.[16][17]Galileo Galilei (/ˌɡælɪˈleɪoʊ/ GAL-il-AY-oh, also US: /-ˈliːoʊ/ -⁠EE-oh, Italian: [ɡaliˈlɛːo ɡaliˈlɛi]; 15 February 1564[3] – 8 January 1642) was an Italian astronomer, physicist and engineer, sometimes described as a polymath.[4] Galileo has been called the "father of observational astronomy",[5] the "father of modern physics",[6][7] the "father of the scientific method",[8] and the "father of modern science".[9][10]