Title: Life of Galileo
Content:  Galileo, an eminent professor and scientist in the 17th century Venetian Republic, is short of money. A prospective student tells him about a novel invention, the telescope ("a queer tube thing"), that is being sold in Amsterdam. Galileo replicates it, and offers it to the Republic as his own creation. He gains an increase in his salary, but within a short time his ruse is discovered. Galileo then uses the telescope for careful observations of the Moon and the planets, and he discovers the moons orbiting Jupiter. His observations strongly support Nicolaus Copernicus' heliocentric model of the Solar System, which is counter both to popular belief and to the doctrine of the powerful Roman Catholic Church. He furthermore publishes in vernacular Italian, rather than traditional scientific Latin, thus making his work and conclusions more accessible to the common people. His daughter's engagement to a 
Title: Galileo affair
Content:   The Galileo affair (il processo a Galileo Galilei) began around 1610 and culminated with the trial and condemnation of Galileo Galilei by the Roman Catholic Inquisition in 1633. Galileo was prosecuted for his support of heliocentrism, the astronomical model in which the Earth and planets revolve around the Sun at the centre of the universe. In 1610, Galileo published his Sidereus Nuncius (Starry Messenger), describing the surprising observations that he had made with the new telescope, among them, the Galilean moons of Jupiter. With these observations and additional observations that followed, such as the phases of Venus, he promoted the heliocentric theory of Nicolaus Copernicus published in De revolutionibus orbium coelestium in 1543. Galileo's discoveries were met with opposition within the Catholic Church, and in 1616 the Inquisition declared heliocentrism to be "formally heretical." Galileo went on to propose a theory of tides in 1616, 
Title: History of physics
Content:  made to observational astronomy include the telescopic confirmation of the phases of Venus; his discovery, in 1609, of Jupiter's four largest moons (subsequently given the collective name of the "Galilean moons"); and the observation and analysis of sunspots. Galileo also pursued applied science and technology, inventing, among other instruments, a military compass. His discovery of the Jovian moons was published in 1610 and enabled him to obtain the position of mathematician and philosopher to the Medici court. As such, he was expected to engage in debates with philosophers in the Aristotelian tradition and received a large audience for his own publications such as the Discourses and Mathematical Demonstrations Concerning Two 
Title: Galilean moons
Content:  body, and also observed that the four were not fixed stars, but rather were orbiting Jupiter. Galileo's discovery proved the importance of the telescope as a tool for astronomers by showing that there were objects in space to be discovered that until then had remained unseen by the naked eye. More importantly, the discovery of celestial bodies orbiting something other than Earth dealt a blow to the then-accepted Ptolemaic world system, which held that Earth was at the center of the universe and all other celestial bodies revolved around it. Galileo's March 13, 1610, Sidereus Nuncius (Starry Messenger), which announced celestial observations through his 
Title: Jupiter
Content:  In 1610, Italian polymath Galileo Galilei discovered the four largest moons of Jupiter (now known as the Galilean moons) using a telescope; thought to be the first telescopic observation of moons other than Earth's. One day after Galileo, Simon Marius independently discovered moons around Jupiter, though he did not publish his discovery in a book until 1614. It was Marius's names for the major moons, however, that stuck: Io, Europa, Ganymede, and Callisto. These findings were the first discovery of celestial motion not apparently centred on Earth. The discovery was a major point in favor of Copernicus' heliocentric theory of the motions of the planets; Galileo's outspoken support of the 
Title: Galileo Galilei
Content:  Galileo di Vincenzo Bonaiuti de' Galilei (, ; 15 February 1564 – 8 January 1642), commonly referred to as Galileo, was an astronomer, physicist and engineer, sometimes described as a polymath, from Pisa, in modern-day Italy. Galileo has been called the "father" of observational astronomy, modern physics, the scientific method, and modern science. 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". He invented the thermoscope and various military compasses, and used the telescope for scientific observations of celestial objects. His contributions to observational astronomy include telescopic confirmation of the phases of Venus, observation of the four largest satellites of Jupiter, observation of Saturn's rings, and analysis of sunspots. Galileo's championing of Copernican 
Title: List of Italian inventions and discoveries
Content:  of observation through quantification, hypothesis and testings of models ): was theorized by Galileo Galilei, recognized as 'the father of modern science, physics and astronomy'. Galilei wanted to reach whatever conclusions a scrupulous and methodical analysis of evidence suggests rather than seeking exclusively the aspects of reality confirming and conforming to a specific orthodoxy. Galileo's method and discoveries represented the focal point for the European scientific revolution in the 17th century. He invalidated a belief system that parted the ancient world from modernity. Galileo revolutionized the goal of science: to research the mathematical properties of substances, such as 'location, motion, shape, size, opacity, 
Title: Io (moon)
Content:  Simon Marius claimed to have discovered Io and the other moons of Jupiter in 1609, one week before Galileo's discovery. Galileo doubted this claim and dismissed the work of Marius as plagiarism. Regardless, Marius's first recorded observation came from 29 December 1609 in the Julian calendar, which equates to 8 January 1610 in the Gregorian calendar, which Galileo used. Given that Galileo published his work before Marius, Galileo is credited with the discovery. For the next two and a half centuries, Io remained an unresolved, 5th-magnitude point of light in astronomers' telescopes. During the 17th century, Io and the other Galilean satellites served a variety of purposes, including early methods to determine longitude, validating Kepler's third 
Title: Exploration of Io
Content:  The first recorded observation of Io was made by Tuscan astronomer Galileo Galilei on January 7, 1610 using a 20x-power, refracting telescope at the University of Padua in the Republic of Venice. The discovery was made possible by the invention of the telescope in the Netherlands a little more than a year earlier and by Galileo's innovations to improve the magnification of the new instrument. During his observation of Jupiter on the evening of January 7, Galileo spotted two stars to the east of Jupiter and another one to the west. Jupiter and these three stars appeared to be in a line 
Title: Conflict thesis
Content:   The Galileo affair was a sequence of events that begin around 1610, culminating with the trial and condemnation of Galileo Galilei by the Roman Catholic Inquisition in 1633 for his support of heliocentrism. In 1610, Galileo published his Sidereus Nuncius (Starry Messenger), describing the surprising observations that he had made with the new telescope, namely the phases of Venus and the Galilean moons of Jupiter. With these observations he promoted the heliocentric theory of Nicolaus Copernicus (published in De revolutionibus orbium coelestium in 1543). Galileo's initial discoveries were met with opposition within the Catholic Church, and in 1616, the Inquisition declared heliocentrism to be formally heretical. Heliocentric books were banned and Galileo was ordered to refrain 

Question: what discovery did galileo make?
Answer: Ganymede.