BALILEO GALILEI

Galileo di Vincenzo Bonaiuti de’ Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei (/ˌɡælɪˈleɪoʊ ˌɡælɪˈleɪ/, US also /ˌɡælɪˈliːoʊ -/; Italian: [ɡaliˈlɛːo ɡaliˈlɛːi]), was an Italian (Florentine) astronomer, physicist and engineer, sometimes described as a polymath. He was born in the city of Pisa, then part of the Duchy of Florence and present-day Italy. Galileo has been called the father of observational astronomy, modern-era classical physics, the scientific method, and modern science.

“Galileo” redirects here. For other uses, see Galileo (disambiguation) and Galileo Galilei (disambiguation).

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 the pendulum and “hydrostatic balances”. He was one of the earliest Renaissance developers of the thermoscope and the inventor of various military compasses. With an improved telescope he built, he observed the stars of the Milky Way, the phases of Venus, the four largest satellites of Jupiter, Saturn’s rings, lunar craters and sunspots. He also built an early microscope.

Galileo’s championing of Copernican heliocentrism was met with opposition from within the Catholic Church and from some astronomers. The matter was investigated by the Roman Inquisition in 1615, which concluded that his opinions contradicted accepted Biblical interpretations.

Galileo later defended his views in Dialogue Concerning the Two Chief World Systems (1632), which appeared to attack Pope Urban VIII and thus alienated both the Pope and the Jesuits, who had both supported Galileo up until this point. 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. During this time, he wrote Two New Sciences (1638), primarily concerning kinematics and the strength of materials.

Early life and family

Galileo was born in Pisa (then part of the Duchy of Florence) on 15 February 1564, the first of six children of Vincenzo Galilei, a leading lutenist, composer, and music theorist, and Giulia Ammannati, the daughter of a prominent merchant, who had married two years earlier in 1562, when he was 42, and she was 24. Galileo became an accomplished lutenist himself and would have learned early from his father a skepticism for established authority.

Three of Galileo’s five siblings survived infancy. The youngest, Michelangelo (or Michelagnolo), also became a lutenist and composer who added to Galileo’s financial burdens for the rest of his life. Michelangelo was unable to contribute his fair share of their father’s promised dowries to their brothers-in-law, who later attempted to seek legal remedies for payments due. Michelangelo also occasionally had to borrow funds from Galileo to support his musical endeavours and excursions. These financial burdens may have contributed to Galileo’s early desire to develop inventions that would bring him additional income.

When Galileo Galilei was eight, his family moved to Florence, but he was left under the care of Muzio Tedaldi for two years. When Galileo was ten, he left Pisa to join his family in Florence, where he came under the tutelage of Jacopo Borghini. He was educated, particularly in logic, from 1575 to 1578 in the Vallombrosa Abbey, about 30 km southeast of Florence.