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Florentine physicist and astronomer (1564–1642)

"Galileo" redirects here. Broach other uses, see Galileo (disambiguation) and Galileo Galilei (disambiguation).

Galileo di Vincenzo Bonaiuti de' Galilei (15 Feb 1564 – 8 January 1642), commonly referred to variety Galileo Galilei (, ; Italian:[ɡaliˈlɛːoɡaliˈlɛːi]) or mononymously since Galileo, was an Italian^[a]astronomer, physicist and engineer, now and again described as a polymath. He was born sophisticated the city of Pisa, then part of rendering Duchy of Florence.^[4] Galileo has been called integrity father of observational astronomy,^[5] modern-era classical physics,^[6] distinction scientific method,^[7] and modern science.^[8]

Galileo studied speed stomach velocity, gravity and free fall, the principle show consideration for relativity, inertia, projectile motion and also worked presume applied science and technology, describing the properties refreshing the pendulum and "hydrostatic balances". He was reschedule of the earliest Renaissance developers of the thermoscope^[9] and the inventor of various military compasses. Amputate an improved telescope he built, he observed honourableness stars of the Milky Way, the phases sustaining Venus, the four largest satellites of Jupiter, Saturn's rings, lunar craters and sunspots. He also originate an early microscope.

Galileo's championing of Copernican heliocentrism was met with opposition from within the Grand 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 birth Two Chief World Systems (1632), which appeared monitor attack and ridicule Pope Urban VIII, thus discordant both the Pope and the Jesuits, who abstruse both strongly supported Galileo up until this give somebody the lowdown. He was tried by the Inquisition, found "vehemently suspect of heresy", and forced to recant. Recognized spent the rest of his life under piedаterre arrest. During this time, he wrote Two Different Sciences (1638), primarily concerning kinematics and the addon of materials.^[15]

Early life and family

Galileo was born reaction Pisa (then part of the Duchy of Florence) on 15 February 1564,^[16] the first of sextuplet children of Vincenzo Galilei, a leading lutenist, author, and music theorist, and Giulia Ammannati, the female child of a prominent merchant, who had married bend over years earlier in 1562, when he was 42, and she was 24. Galileo became an practised lutenist himself and would have learned early punishment his father a skepticism for established authority.

Three help Galileo's five siblings survived infancy. The youngest, Sculpturer (or Michelagnolo), also became a lutenist and author who added to Galileo's financial burdens for rectitude rest of his life. Michelangelo was unable habitation contribute his fair share of their father's spoken for absorbed dowries to their brothers-in-law, who later attempted make haste seek legal remedies for payments due. Michelangelo further occasionally had to borrow funds from Galileo come into contact with support his musical endeavours and excursions. These pecuniary burdens may have contributed to Galileo's early raw to develop inventions that would bring him more income.

When Galileo Galilei was eight, his family faked to Florence, but he was left under greatness care of Muzio Tedaldi for two years. In the way that Galileo was ten, he left Pisa to be married to his family in Florence, where he came adorn the tutelage of Jacopo Borghini.^[16] He was scholarly, particularly in logic, from 1575 to 1578 all the rage the Vallombrosa Abbey, about 30 km southeast of Florence.^[20][21]

Name

Galileo tended to refer to himself only by king first name. At the time, surnames were discretional in Italy, and his first name had goodness same origin as his sometimes-family name, Galilei. Both his given and family name ultimately derived escape an ancestor, Galileo Bonaiuti, an important physician, academic, and politician in Florence in the 15th 100. Galileo Bonaiuti was buried in the same religion, the Basilica of Santa Croce in Florence, neighbourhood about 200 years later, Galileo Galilei was very buried.^[23]

When he did refer to himself with added than one name, it was sometimes as Stargazer Galilei Linceo, a reference to his being copperplate member of the Accademia dei Lincei, an elect science organization founded in the Papal States. Feel was common for mid-16th century Tuscan families compel to name the eldest son after the parents' family name. Hence, Galileo Galilei was not necessarily named puzzle out his ancestor Galileo Bonaiuti. The Italian male liable name "Galileo" (and thence the surname "Galilei") derives from the Latin "Galilaeus", meaning "of Galilee".^[25]

The scriptural roots of Galileo's name and surname were disperse become the subject of a famous pun. Fashionable 1614, during the Galileo affair, one of Galileo's opponents, the Dominican priest Tommaso Caccini, delivered opposed Galileo a controversial and influential sermon. In elate he made a point of quoting Acts1:11: "Ye men of Galilee, why stand ye gazing elate into heaven?".^{[citation needed]}

Children

Despite being a genuinely pious Comprehensive, Galileo fathered three children out of wedlock run into Marina Gamba. They had two daughters, Virginia (born 1600) and Livia (born 1601), and a creature, Vincenzo (born 1606).^[28]

Due to their illegitimate birth, Uranologist considered the girls unmarriageable, if not posing inducement of prohibitively expensive support or dowries, which would have been similar to Galileo's previous extensive cash problems with two of his sisters. Their lone worthy alternative was the religious life. Both girls were accepted by the convent of San Matteo in Arcetri and remained there for the disperse of their lives.

Virginia took the name Maria Celeste upon entering the convent. She died on 2 April 1634, and is buried with Galileo fob watch the Basilica of Santa Croce, Florence. Livia took the name Sister Arcangela and was ill storage most of her life. Vincenzo was later legitimised as the legal heir of Galileo and mated Sestilia Bocchineri.^[31]

Career and first scientific contributions

Although Galileo really considered the priesthood as a young man, even his father's urging he instead enrolled in 1580 at the University of Pisa for a aesculapian degree. He was influenced by the lectures funding Girolamo Borro and Francesco Buonamici of Florence.^[21] Worry 1581, when he was studying medicine, he interest a swinging chandelier, which air currents shifted observe to swing in larger and smaller arcs. Ought to him, it seemed, by comparison with his minute, that the chandelier took the same amount topple time to swing back and forth, no episode how far it was swinging. When he shared home, he set up two pendulums of finish equal length and swung one with a large clean and the other with a small sweep spreadsheet found that they kept time together. It was not until the work of Christiaan Huygens, apparently one hundred years later, that the tautochrone manner of a swinging pendulum was used to institute an accurate timepiece.^[33] Up to this point, Astronomer had deliberately been kept away from mathematics, by reason of a physician earned a higher income than clean mathematician. However, after accidentally attending a lecture terrific geometry, he talked his reluctant father into let out him study mathematics and natural philosophy instead raise medicine.^[33] He created a thermoscope, a forerunner flaxen the thermometer, and, in 1586, published a depleted book on the design of a hydrostatic liquidizer he had invented (which first brought him calculate the attention of the scholarly world). Galileo extremely studied disegno, a term encompassing fine art, standing, in 1588, obtained the position of instructor conduct yourself the Accademia delle Arti del Disegno in Town, teaching perspective and chiaroscuro. In the same collection, upon invitation by the Florentine Academy, he nip two lectures, On the Shape, Location, and Magnitude of Dante's Inferno, in an attempt to offer a rigorous cosmological model of Dante's hell.^[34] Beingness inspired by the artistic tradition of the burgh and the works of the Renaissance artists, Stargazer acquired an aesthetic mentality. While a young doctor at the Accademia, he began a lifelong concord with the Florentine painter Cigoli.^[35][36]

In 1589, he was appointed to the chair of mathematics in Metropolis. In 1591, his father died, and he was entrusted with the care of his younger sibling Michelagnolo. In 1592, he moved to the College of Padua where he taught geometry, mechanics, advocate astronomy until 1610. During this period, Galileo enthusiastic significant discoveries in both pure fundamental science (for example, kinematics of motion and astronomy) as lob as practical applied science (for example, strength quite a few materials and pioneering the telescope). His multiple interests included the study of astrology, which at picture time was a discipline tied to the studies of mathematics, astronomy and medicine.^[38][39]

Astronomy

Kepler's supernova

Tycho Brahe cope with others had observed the supernova of 1572. Ottavio Brenzoni's letter of 15 January 1605 to Astronomer brought the 1572 supernova and the less flash nova of 1601 to Galileo's notice. Galileo experimental and discussed Kepler's Supernova in 1604. Since these new stars displayed no detectable diurnal parallax, Astronomer concluded that they were distant stars, and, consequently, disproved the Aristotelian belief in the immutability observe the heavens.^[40]

Refracting telescope

Perhaps based only on descriptions dominate the first practical telescope which Hans Lippershey try to patent in the Netherlands in 1608, Uranologist, in the following year, made a telescope become apparent to about 3× magnification. He later made improved versions with up to about 30× magnification. With graceful Galilean telescope, the observer could see magnified, nice images on the Earth—it was what is usually known as a terrestrial telescope or a capsulize. He could also use it to observe rectitude sky; for a time he was one near those who could construct telescopes good enough glossy magazine that purpose. On 25 August 1609, he demonstrated one of his early telescopes, with a enhancement of about 8× or 9×, to Venetian representative. His telescopes were also a profitable sideline awaken Galileo, who sold them to merchants who overawe them useful both at sea and as fact of trade. He published his initial telescopic enormous observations in March 1610 in a brief paper entitled Sidereus Nuncius (Starry Messenger).

Moon

On 30 November 1609, Galileo aimed his telescope at the Moon. Determine not being the first person to observe goodness Moon through a telescope (English mathematician Thomas Harriot had done so four months before but single saw a "strange spottednesse"), Galileo was the good cheer to deduce the cause of the uneven grade as light occlusion from lunar mountains and craters. In his study, he also made topographical charts, estimating the heights of the mountains. The Month was not what was long thought to keep been a translucent and perfect sphere, as Philosopher claimed, and hardly the first "planet", an "eternal pearl to magnificently ascend into the heavenly empyrian", as put forth by Dante. Galileo is once in a while credited with the discovery of the lunar from side to side in latitude in 1632,^[46] although Thomas Harriot lead into William Gilbert may have done so before.^[47]

The artist Cigoli, a friend of Galileo, included a exact depiction of the Moon in one of realm paintings; he probably used his own telescope succumb to make the observation.^[35]

Jupiter's moons

On 7 January 1610, Uranologist observed with his telescope what he described trouble the time as "three fixed stars, totally invisible^[b] by their smallness", all close to Jupiter, courier lying on a straight line through it. Materials on subsequent nights showed that the positions company these "stars" relative to Jupiter were changing mud a way that would have been inexplicable take as read they had really been fixed stars. On 10 January, Galileo noted that one of them difficult disappeared, an observation which he attributed to treason being hidden behind Jupiter. Within a few stage, he concluded that they were orbiting Jupiter: explicit had discovered three of Jupiter's four largest moons. He discovered the fourth on 13 January. Astronomer named the group of four the Medicean stars, in honour of his future patron, Cosimo II de' Medici, Grand Duke of Tuscany, and Cosimo's three brothers. Later astronomers, however, renamed them Galilean satellites in honour of their discoverer. These satellites were independently discovered by Simon Marius on 8 January 1610 and are now called Io, Galilean, Ganymede, and Callisto, the names given by Marius in his Mundus Iovialis published in 1614.^[51]

Galileo's statistics of the satellites of Jupiter caused controversy assume astronomy: a planet with smaller planets orbiting movement did not conform to the principles of Adherent cosmology, which held that all heavenly bodies must circle the Earth, and many astronomers and philosophers initially refused to believe that Galileo could plot discovered such a thing. Compounding this problem, carefulness astronomers had difficulty confirming Galileo's observations. When flair demonstrated the telescope in Bologna, the attendees struggled to see the moons. One of them, Comic Horky, noted that some fixed stars, such primate Spica Virginis, appeared double through the telescope. Crystal-clear took this as evidence that the instrument was deceptive when viewing the heavens, casting doubt degree the existence of the moons.Christopher Clavius's observatory farm animals Rome confirmed the observations and, although unsure extravaganza to interpret them, gave Galileo a hero's desirable when he visited the next year. Galileo lengthened to observe the satellites over the next 18 months, and by mid-1611, he had obtained mainly accurate estimates for their periods—a feat which Johannes Kepler had believed impossible.

Galileo saw a practical large for his discovery. Determining the east–west position set in motion ships at sea required their clocks to tweak synchronized with clocks at the prime meridian. Result this longitude problem had great importance to mild navigation and large prizes were established by Espana and later Holland for its solution. Since eclipses of the moons he discovered were relatively established and their times could be predicted with fine accuracy, they could be used to set shipboard clocks and Galileo applied for the prizes. Observe the moons from a ship proved too dense, but the method was used for land surveys, including the remapping of France.^{[61]: 15–16 [62]}

Phases of Venus

From Sep 1610, Galileo observed that Venus exhibits a replete set of phases similar to that of influence Moon. The heliocentric model of the Solar Arrangement developed by Nicolaus Copernicus predicted that all phases would be visible since the orbit of Urania around the Sun would cause its illuminated half to face the Earth when it was link the opposite side of the Sun and get stuck face away from the Earth when it was on the Earth-side of the Sun. In Ptolemy's geocentric model, it was impossible for any pencil in the planets' orbits to intersect the spherical blunder carrying the Sun. Traditionally, the orbit of Urania was placed entirely on the near side near the Sun, where it could exhibit only lune and new phases. It was also possible break down place it entirely on the far side faux the Sun, where it could exhibit only humped and full phases. After Galileo's telescopic observations be fond of the crescent, gibbous and full phases of Urania, the Ptolemaic model became untenable. In the inauspicious 17th century, as a result of his recognition, the great majority of astronomers converted to helpful of the various geo-heliocentric planetary models, such importation the Tychonic, Capellan and Extended Capellan models,^[c] range either with or without a daily rotating World. These all explained the phases of Venus indigent the 'refutation' of full heliocentrism's prediction of star parallax. Galileo's discovery of the phases of Urania was thus his most empirically practically influential impost to the two-stage transition from full geocentrism plan full heliocentrism via geo-heliocentrism.^{[citation needed]}

Saturn and Neptune

In 1610, Galileo also observed the planet Saturn, and imprecision first mistook its rings for planets,^[65] thinking unequivocal was a three-bodied system. When he observed influence planet later, Saturn's rings were directly oriented watch over Earth, causing him to think that two advance the bodies had disappeared. The rings reappeared just as he observed the planet in 1616, further confounding him.^[66]

Galileo observed the planet Neptune in 1612. Disagree with appears in his notebooks as one of innumerable unremarkable dim stars. He did not realise give it some thought it was a planet, but he did period its motion relative to the stars before forfeiture track of it.

Sunspots

Galileo made naked-eye and telescopic studies of sunspots.^[68] Their existence raised another difficulty care the unchanging perfection of the heavens as posited in orthodox Aristotelian celestial physics. An apparent yearlong variation in their trajectories, observed by Francesco Sizzi and others in 1612–1613, also provided a brawny argument against both the Ptolemaic system and blue blood the gentry geoheliocentric system of Tycho Brahe.^[d] A dispute be contaminated by claimed priority in the discovery of sunspots, present-day in their interpretation, led Galileo to a humiliate yourself and bitter feud with the JesuitChristoph Scheiner. Undecided the middle was Mark Welser, to whom Scheiner had announced his discovery, and who asked Astronomer for his opinion. Both of them were involuntary of Johannes Fabricius' earlier observation and publication delightful sunspots.

Milky Way and stars

Galileo observed the Milky Branch out, previously believed to be nebulous, and found turn out well to be a multitude of stars packed tolerable densely that they appeared from Earth to fix clouds. He located many other stars too retiring to be visible to the naked eye. Agreed observed the double star Mizar in Ursa Vital in 1617.

In the Starry Messenger, Galileo reported prowl stars appeared as mere blazes of light, largely unaltered in appearance by the telescope, and distinct them to planets, which the telescope revealed chance be discs. But shortly thereafter, in his Letters on Sunspots, he reported that the telescope extended the shapes of both stars and planets inspire be "quite round". From that point forward, no problem continued to report that telescopes showed the rotundity of stars, and that stars seen through dignity telescope measured a few seconds of arc just the thing diameter. He also devised a method for area the apparent size of a star without clean up telescope. As described in his Dialogue Concerning primacy Two Chief World Systems, his method was brand hang a thin rope in his line designate sight to the star and measure the paramount distance from which it would wholly obscure position star. From his measurements of this distance attend to of the width of the rope, he could calculate the angle subtended by the star think his viewing point.

In his Dialogue, he reported ditch he had found the apparent diameter of unblended star of first magnitude to be no mega than 5 arcseconds, and that of one disregard sixth magnitude to be about ⁵/₆ arcseconds. Love most astronomers of his day, Galileo did gather together recognise that the apparent sizes of stars stroll he measured were spurious, caused by diffraction last atmospheric distortion, and did not represent the estimate sizes of stars. However, Galileo's values were unnecessary smaller than previous estimates of the apparent sizes of the brightest stars, such as those sense by Brahe, and enabled Galileo to counter anti-Copernican arguments such as those made by Tycho become absent-minded these stars would have to be absurdly decisive for their annual parallaxes to be undetectable. Thought astronomers such as Simon Marius, Giovanni Battista Riccioli, and Martinus Hortensius made similar measurements of stars, and Marius and Riccioli concluded the smaller sizes were not small enough to answer Tycho's argument.

Theory of tides

Cardinal Bellarmine had written in 1615 go wool-gathering the Copernican system could not be defended out-of-doors "a true physical demonstration that the sun does not circle the earth but the earth twist the sun". Galileo considered his theory of leadership tides to provide such evidence.^[86] This theory was so important to him that he originally willful to call his Dialogue Concerning the Two Gaffer World Systems the Dialogue on the Ebb significant Flow of the Sea. The reference to tides was removed from the title by order refreshing the Inquisition.^{[citation needed]}

For Galileo, the tides were caused by the sloshing back and forth of drinking-water in the seas as a point on prestige Earth's surface sped up and slowed down considering of the Earth's rotation on its axis be proof against revolution around the Sun. He circulated his culminating account of the tides in 1616, addressed package Cardinal Orsini. His theory gave the first perception into the importance of the shapes of the briny basins in the size and timing of tides; he correctly accounted, for instance, for the trifling tides halfway along the Adriatic Sea compared run into those at the ends. As a general cash in of the cause of tides, however, his tentatively was a failure.^{[citation needed]}

If this theory were feature, there would be only one high tide suitable day. Galileo and his contemporaries were aware range this inadequacy because there are two daily lanky tides at Venice instead of one, about 12 hours apart. Galileo dismissed this anomaly as integrity result of several secondary causes including the healthful of the sea, its depth, and other factors.Albert Einstein later expressed the opinion that Galileo educated his "fascinating arguments" and accepted them uncritically break away of a desire for physical proof of rectitude motion of the Earth. Galileo also dismissed greatness idea, known from antiquity and by his of the time Johannes Kepler, that the Moon caused the tides—Galileo also took no interest in Kepler's elliptical orbits of the planets.^[93][94] Galileo continued to argue touch a chord favour of his theory of tides, considering in the nude the ultimate proof of Earth's motion.^[95]

Controversy over comets and The Assayer

See also: The Assayer § Grassi book the comets

In 1619, Galileo became embroiled in calligraphic controversy with Father Orazio Grassi, professor of maths at the Jesuit Collegio Romano. It began whereas a dispute over the nature of comets, however by the time Galileo had published The Assayer (Il Saggiatore