Galileo Galilei was born in the city of Pisa, in the northern Italian region of Tuscany, on February 15, 1564. His father was Vincenzo Galilei, an accomplished musician who worked as a wool trader. Galileo’s mother came from a higher social station than her husband, and she has been described as a shrewish, demanding woman, ever resentful of Vincenzo’s failure to rise above his lower-class origins. Galileo being a great Italian astronomer, mathematician, and physicist laid foundations for modern experimental science, and by the construction of astronomical telescopes he greatly enlarged humanity’s vision of the universe.
Timeline and Facts about Galileo’s Life
February 18, 1564 : When and where was Gelileo born? birth of Galileo Galilei in the Tuscan city of Pisa
1581 : Where did galileo go to school? Galileo enrolls in the University of Pisa to pursue a degree in medicine
1585 : Galileo leaves the University of Pisa without having obtained a degree
1589 : Galileo hired as a lecturer in mathematics at the University of Pisa
1589-1592 : Galileo teaches in Pisa, and reportedly makes his famous velocity experiment, dropping objects off the leaning tower to disprove Aristotle’s theory that heavier objects fall faster than lighter ones
1604 : Appearance of Kepler’s Nova in the sky; Galileo debates its significance with conservative scholars.
March 1610 : Publication of Sidereus Nuncius, dedicated to the Grand Duke of Tuscany, Cosimo II
June 1610 : Galileo leaves Padua to take a new, more lucrative position in Tuscany
1612 : Galileo Galilei was the first astronomer to observe the planet Neptune when it was in conjunction with Jupiter. Neptune was not truly discovered until 1846, about 234 years after Galileo first sighted it with his telescope.
December 1614 : Father Tommasso Caccini attacks Galileo in sermon in Florence, and later denounces him to the Inquisition
March 1615 : Papal commission issues edict against Copernican theory; Cardinal Bellarmine orders Galileo to cease in his support of heliocentricity
October 1623 : Galileo’s treatise on comets, The Assayer, is published with Urban VIII’s blessing
1624-1629 : Galileo works on his Dialogue Concerning the Two Chief World Systems from his home outside Florence
February 1632 : Dialogue Concerning the Two Chief World Systems published in Florence, with tentative Papal approval
August 1632 : Inquisition bans further printing of the Dialogue
September 23, 1632 : Galileo summoned to Rome
February 13, 1633 : Galileo arrives in Rome
April 12, 1633 : Galileo interrogated for the first time. Afterwards, he is imprisoned in the Vatican for three weeks.
April 30, 1633 : Galileo interrogated again, and allowed to return to the home of the Tuscan ambassador
May 10, 1633 : Third interrogation; Galileo begs for mercy.
June 21, 1633 : Final interrogation and Galileo is officially charged with heresy; he is forced to confess his errors, renounce the Copernican system, and accept the Church’s judgment.
1638 : Galileo’s Dialogues Concerning Two New Sciences is published in Holland. John Milton visits Galileo in Arcetri.
January 8, 1642 : When did galileo galilei die? Death of Galileo
1822 : Galileo Galilei’s “Dialogue” taken off the Index Librorum Prohibitorum, the Roman Catholic Church’s list of banned books.
1983 : Pope John Paul II retracts the ban on Galileo Galilei.
1992 : Pope John Paul II issues an apology, and lifts the edict of the Inquisition against Galileo Galilei.
- “I do not feel obliged to believe that the same God who has endowed us with sense, reason, and intellect has intended us to forgo their use.”
- “The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the Universe to do.”
- “I have never met a man so ignorant that I couldn’t learn something from him.”
- “In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual.”
- “Where the senses fail us, reason must step in.”
- “The Bible shows the way to go to heaven, not the way the heavens go”
- “Nature is relentless and unchangeable, and it is indifferent as to whether its hidden reasons and actions are understandable to man or not.”
- “So far as I know, no one has yet pointed out that the distance travelled in equal intervals of time, by a body falling from rest, stand to one another in the same ratio as the odd number beginning with 1′.”
- “I’ve loved the stars too fondly to be fearful of the night”
Galileo’s Contributions to Physics
It is said that at the age of 19, in the cathedral of Pisa, he timed the oscillations of a swinging lamp by means of his pulse beats and found the time for each swing to be the same, no matter what the amplitude of the oscillation, thus discovering the isochronal nature of the pendulum, which he verified by experiment.
Galileo soon became known through his invention of a hydrostatic balance and his treatise on the center of gravity of solid bodies. He found that bodies do not fall with velocities proportional to their weights, but he did not arrive at the correct conclusion until perhaps 20 years later.
The famous story in which Galileo is said to have dropped weights from the Leaning Tower of Pisa is apocryphal. The actual experiment was performed by Simon Stevin several years before Galileo’s work.
However, Galileo did find that the path of a projectile is a parabola, and he is credited with conclusions foreshadowing the laws of motion by Isaac Newton.
Galileo’s Contributions to Astronomy
There, in 1609, having heard reports of a simple magnifying instrument put together by a lens-grinder in Holland, he constructed the first complete astronomical telescope.
Exploring the heavens with his new aid, Galileo discovered that the moon, shining with reflected light, had an uneven, mountainous surface and that the Milky Way was made up of numerous separate stars.
In 1610 he discovered the four largest satellites of Jupiter, the first satellites of a planet other than Earth to be detected.
He observed and studied the oval shape of Saturn, the phases of Venus, and the spots on the sun.
His investigations confirmed his acceptance of the Copernican theory of the solar system.