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Birth of Galileo Galilei

15/02/1564View on timeline

Galileo Galilei (Italian: [ɡaliˈlɛːo ɡaliˈlɛi]; 15 February 1564 – 8 January 1642) was an Italian polymath. Known for his work as astronomer, physicist, engineer, philosopher, and mathematician, Galileo has been called the "father of observational astronomy", the "father of modern physics", the "father of the scientific method", and even the "father of 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", 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 and the analysis of sunspots.

Galileo's championing of heliocentrism and Copernicanism was controversial during his lifetime, when most subscribed to either geocentrism or the Tychonic system. He met with opposition from astronomers, who doubted heliocentrism because of the absence of an observed stellar parallax. 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."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. 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. 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.

Portrait of Galileo Galilei (1636), by Justus Sustermans


1543 – Nicolaus Copernicus publishes De revolutionibus orbium coelestium as an alternative world system to the Ptolemy's geocentric model causing subsequent questions to be raised about Aristotelian physics following Copernicus' death

1563 – Parents Vincenzo Galilei and Giulia Ammannati marry

1564 – Birth in Pisa, Italy

1570 – Thomas Digges publishes Pantometria describing a telescope built between 1540–1559 by his father Leonard Digges

1573 – Tycho Brahe publishes De nova stella (On the new star) refuting Aristotelian belief in immutable celestial spheres and an eternal, unchanging, more perfect heavenly realm of celestial aether above the moon

1576 – Giuseppe Moletti, Galileo's predecessor in the mathematics chair at Padua, reports falling bodies of the same shape fall at the same speed, regardless of material

1581 – His father, Vincenzo Galilei publishes Dialogo della musica antica et moderna formulating musical theories

1581 – Enrols as medical student at University of Pisa

1582 – Attends mathematics lecture by Ostilio Ricci and decides to study math and science

1585 – Leaves University of Pisa without degree and works as tutor

1586 – Invents hydrostatic balance; wrote La Balancitta (The little balance)

1586 – Simon Stevin publishes results for dropping lead weights from 10 meters

1588 – Tycho Brahe publishes work on comets containing a description of the Tychonic system of the world

1589 – Appointed to Mathematics Chair, University of Pisa

1590 – Partially completes De Motu (On Motion), which is never published

1591 – Death of his father, Vicenzo Galilei

1592 – Appointed professor of mathematics at University of Padua, remains 18 years

1593 – Invents early thermometer that unfortunately depended on both temperature and pressure

1595 – Invents improved ballistics calculation geometric and military compass, which he later improves for surveying and general calculations and earns income from tutoring on its use

1597 – Letter to Kepler indicates his belief in the Copernican System

1600 – First child, Virginia is born; ~1600 Le Meccaniche (Mechanics)

1600 – William Gilbert publishes On the Magnet and Magnetic Bodies, and on That Great Magnet the Earth with arguments supporting the Copernican system

1600 – Roman Inquisition finds Giordano Bruno, Copernican system supporter, guilty of heresy for opinions on pantheism and the eternal plurality of worlds, and for denial of the Trinity, divinity of Christ, virginity of Mary, and Transubstantiation; burned at the stake by civil authorities

1601 – Daughter Livia is born

1604 – Measures supernova position indicating no parallax for the new star

1605 – Sued by brothers-in-law for nonpayment of sisters' dowries

1606 – Son Vincenzo born

1606 – Publishes manual for his calculating compass

1607 – Rotilio Orlandini attempts to assassinate Galileo's friend, Friar Paolo Sarpi

1608 – Hans Lippershey invents a refracting telescope

1609 – Independently invents and improves telescopes based on description of invention by Hans Lippershey

1609 – Kepler publishes Astronomia nova containing his first two laws and for the first time demonstrates the Copernican model is more accurate than the Ptolemaic for uses such as navigation and prediction

1609 – Thomas Harriot sketches the Moon from telescopic observations made four months before Galileo's

1610 – Publishes Sidereus Nuncius (Starry Messenger); views our moon's mountains and craters and brightest 4 of Jupiter's moons

1610 – Martin Horky publishes Brevissima Peregrinatio Contra Nuncium Sidereum, opposing Galileo

1610 – Kepler requests one of Galileo's telescopes or lenses, but Galileo replies he is too busy to build one and has no extras

1610 – Lifetime appointment to mathematics position at University of Padua, and as mathematician and philosopher for Cosimo II, Grand Duke of Tuscany

1611 – Discovers phases of Venus; granted audience with Pope; made member of Lincean Academy

1611 – Awarded an honorary degree by the Jesuit College in Rome

1611 – David Fabricius publishes Narration on Spots Observed on the Sun and their Apparent Rotation with the Sun prior to Christoph Scheiner and Galileo's published works on the subject

1612 – Proposed Jupiter's moons could be used as a universal clock for possible determination of longitude

1612 or 1613 – Francesco Sizzi discovers annual variations in sunspots' motions

1613 – Letters on Sunspots

1613 – Letter to Benedetto Castelli discussing the rotation of the sun and Galileo's support of the Copernican system. Using Biblical inerrancy as a basis, Galileo writes that Joshua's command for the sun to stand still in Joshua 10:13 proves the "impossibility of the Aristotelian and Ptolemaic world system, and on the other hand agrees very well with the Copernican one."He went on to write that "the sun gives not only light (as it obviously does) but also motion to all the planets that revolve around it" by its rotation

1615 – Letter to Grand Duchess Christina (not published until 1636)

1616 – Officially warned by the Church not to hold or defend the Copernican System

1616 – The Catholic Church places De revolutionibus orbium coelestium on the List of Prohibited Books, pending correction

1616 – Private letter "Discourse on the Tides"

1617 – Moves into Bellosguardo, west of Florence, near his daughters' convent; observes double star Mizar in Ursa Major

1619 – Kepler publishes Harmonices Mundi which introduces his third law

1619 – Discourse on the Comets

1623 – Maffeo Barberini becomes Pope Urban VIII

1623 – Publishes The Assayer

1624 – Visits Pope who praises and honours him, leaving with assumed permission to publish work on the Copernican vs. Ptolemaic Systems; used a compound microscope

1625 – Illustrations of insects made using one of Galileo's microscopes published

1630 – Completes Dialogue Concerning the Two Chief World Systems and subsequently receives approval of Church censor

1630 - Invited by Grand Duke Ferdinand II of Tuscany to advise on proposed engineering works on the Bisenzio River

1631 - Produces report on the Bisenzio engineering proposals, arguing against them

1632 – Publishes Dialogue Concerning the Two Chief World Systems

1633 – sentenced by the Inquisition to imprisonment, commuted to house arrest, for vehement suspicion of heresy in violating the 1616 injunction

1633 – Catholic Church places Dialogue Concerning the Two Chief World Systems on the List of Prohibited Books

1638 – Publishes Dialogues Concerning Two New Sciences

1642 – Death in Arcetri, Italy

1668 – Isaac Newton builds his reflecting telescope

1687 – Newton publishes Philosophiæ Naturalis Principia Mathematica deriving Kepler's laws from the Universal Law of Gravitation and the Laws of Motion

2016 – The American Juno spacecraft, carrying a plaque and a Lego minifigure dedicated at Galileo, arrives at Jupiter's orbit

Galileo Galilei Documentary The World Changes



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Published in 5/10/2018

Updated in 19/02/2021

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