Galileo Galilei Biography

(Known as “Father” of Observational Astronomy who Invented the ‘Thermoscope’ and Various Military Compasses)

Birthday: February 15, 1564 (Aquarius)

Born In: Pisa, Italy

Often remembered as the ‘Father of Observational Astronomy,’ Galileo Galilei was one of the most celebrated and illustrious astronomers, mathematicians, and physicists in the history of mankind. He played a major role and was instrumental in establishing the scientific revolution. Galileo is credited for developing much of the modern concepts, which have proved to be the foundation for the present-day research on various fields. Throughout his life, Galileo greatly contributed to astronomical observatory. He bettered the telescope, which assisted him in his discoveries. He also dismissed the Aristotelian view, which was dominant in that era, and supported Copernicanism. His contribution in the field of astronomy includes the telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter, and the observation and analysis of sunspots. Furthermore, he invented an improved military compass and other instruments in the field of applied science and technology. He championed the heliocentric view and supported Copernicanism which irked the Roman Catholic Church. Nevertheless, with the dawn of the 20th century, the Church lifted the ban imposed on Galileo’s books and acclaimed him as the ‘Father of Modern Sciences.’

Quick Facts

Italian Celebrities Born In February

Also Known As: Galileo di Vincenzo Bonaiuti de' Galilei

Died At Age: 77


father: Vincenzo Galilei

mother: Giulia Ammannati

siblings: Benedetto Galilei, Giulia Galilei, Livia Galilei, Michelagnolo, Virginia Galile

children: Livia, Maria Celeste, Vincenzo Gamba

Partner: Marina Gamba

Born Country: Italy

Quotes By Galileo Galilei Physicists

Died on: January 8, 1642

place of death: Arcetri, Italy

City: Pisa, Italy

Notable Alumni: University Of Pisa

discoveries/inventions: Ganymede, Europa, Callisto, Io, Rings Of Saturn

More Facts

education: University Of Pisa

Childhood & Early Life
Galileo Galilei was born Galileo di Vincenzo Bonaulti de Galilei on 15 February 1564, in Pisa, Duchy of Florence, to Vincenzo Galilei and Giulia Ammannati. His father was a lutenist, composer, and music theorist by profession. At an early age, Galileo learned the technicalities involved in lute and became an accomplished lutenist.
He aspired to take up priesthood when he grew up. However, his father wanted Galileo to be in the field of medicine as it promised a secured financial future. Complying with the wishes of his father, Galileo took to studying at the ‘University of Pisa’ for a medical degree.
There were two incidents which led Galileo to move from being a physician to a mathematician. The first was in 1581 when Galileo noticed that a chandelier took almost the same time to swing back and forth regardless of its swing varying from smaller to larger arcs. Amused by it, he set up two pendulums of equal length and swung them with a variation in sweep. Interestingly, both the pendulums, irrespective of their sweeps, took the same amount of time to return to the starting position and synchronized with each other.
The second incident was a lecture of geometry which he attended accidentally. Both the incidents made Galileo realize his true calling and he finally convinced his father to allow him to study mathematics and natural philosophy.
Galileo was exposed to the Aristotelian view of the world during his years in Pisa. Though not entirely correct, it was the then leading scientific theory, and the only one to be sanctioned by the Roman Catholic Church.
Though Galileo, like any other intellectual of that age, supported the Aristotelian view initially, he eventually drifted away from the same. Financial difficulties cut short Galileo’s education at the university, which he left in 1585, before earning his degree.
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Academic Career
Upon leaving the university, Galileo set his mind to create a thermoscope, which was a precursor to the presently used thermometer. He then published a small book titled ‘The Little Balance’ which highlighted his work on hydrostatic balance. It was this work that brought Galileo recognition and name in the scholarly world.
To support himself, Galileo took up the job as an instructor at ‘Accademia delle Arti del Disegno’ in Florence; his profile included teaching perspective and chiaroscuro. Simultaneously, he studied disegno and became quite interested in the artistic traditions of the city. Galileo also developed a profound interest in the works of the Renaissance artists.
No sooner than in 1589, Galileo was promoted to the chair of mathematics at the ‘University of Pisa.’ During his term at Pisa, Galileo conducted his famous experiment of dropping items of varied weight from the top of the Leaning Tower.
It was through the findings of the experiments that Galileo rejected Aristotle’s claim that speed of the falling object is directly proportional to its weight. He mentioned the outcome of the experiment in his paper titled ‘De Motu’ (On Motion). Instead of taking Aristotle’s view of motion, Galileo took Archimedean approach to the problem.
Due to his rejection of Aristotelian view, Galileo gained an unpopular status within the society. In 1592, his contract was not renewed at the ‘University of Pisa,’ due to which he lost his position. However, Galileo’s patrons helped him secure the chair of mathematics at the ‘University of Padua,’ which he served for 18 years.
At the ‘University of Padua,’ Galileo taught young students geometry, mechanics, and astronomy. The appointment came at a perfect time as Galileo had to support his family due to the death of his father.
Since the salary earned at the university was not enough to cover all the expenses of the family and for the treatment of his younger brother Michelagnolo, Galileo started imparting private lessons to well-to-do boarding students.
His Discoveries
It was during his years at the University of Padua that Galileo made significant discoveries in the field of pure fundamental science as well as practical applied science.
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Based on Hans Lippershey's uncertain descriptions of a practical telescope, Galileo constructed a telescope with 3x magnification in 1609. He not only invented his own version of the telescope, but also bettered his own technique to improve the instrument.
Galileo learned the art of lens grinding, which helped him produce increasingly powerful telescope. He presented the same to the Venetian Senate, which was impressed by the invention. Subsequently, his salary was doubled, thanks to his invention.
Working further on the functioning of the telescope, Galileo bettered the instrument, so much so that it could magnify up to 20 times. The telescope helped him have a clear vision of the Moon and its surface. It was through Galileo’s telescope that the Moon’s rocky and uneven surface was first noticed.
In 1610, Galileo discovered the moons revolving around Jupiter. He also claimed that there was more number of stars in the universe than those visible through naked eyes. He even discovered that Venus goes through phases just as the Moon does and that Saturn looks different from that of other planets.
These ground-breaking discoveries made by Galileo were written in a small book titled 'Sidereus Nuncius' (The Starry Messenger). He dedicated the book to Cosimo II de’ Medici, the grand duke of his native, Tuscany.
Impressed by the research made by Galileo, the Grand Duke of Tuscany rewarded him with an appointment as mathematician and philosopher.
Galileo’s discoveries did not prove the fact that Earth was a planetary body and that it revolved around the Sun. However, it did dismiss Aristotelian cosmology and favored Copernicus theory which stated that the Sun is the center of the universe and that the Earth is a planet. Also Aristotle’s claim of each body in the universe other than the Earth being perfect and unchanging was also challenged and proven wrong.
Next, Galileo turned his attention towards what made certain objects float in water. Once again, he negated Aristotle’s opinion that objects floated due to their flat shape. Instead, he argued that the flotation was caused due to the weight of the object in relation to the water it displaced. He mentioned the same in his 1612 published work ‘Floating Bodies.’
The following year, Galileo came up with his theory of sunspots, which he explained in his book 'Istoria e dimostrazioni intorno alle macchie solari' (History and Demonstrations Concerning Sunspots and Their Properties). In the book, Galileo contradicted Aristotelian doctrine that the Sun was perfect.
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Galileo further stated that Copernican theory did not refute the Biblical passages. Instead, it provided a different, more accurate perspective about things. However, he was banned from the Church for defending the Copernican theory. The Church also prohibited him from teaching or holding the theory, to which he conceded.
Each of Galileo’s discoveries proved his disapproval of the Aristotelian view and his approval of Copernicanism, so much so that by the end of it all, Galileo converted to Copernicanism, which proved to be a key turning point in the scientific revolution.
With the emergence of a new Pope Urban VIII, who fortunately was a friend, admirer, and patron of Galileo, Galileo resumed his works on astronomy. He was even allowed to publish books, given that his books provide an objective view instead of advocating Copernican theory.
In 1632, Galileo came up with his book 'Dialogue Concerning the Two Chief World Systems.’ The book dealt with views and opinions of three people. While the first person supported Copernicus' heliocentric theory of the universe, the second argued against it. The third person was objective and had an unbiased line of belief.
Though Galileo claimed that the book was neutral and impartial, it spiked a negative reaction from the Church, and Galileo was summoned to Rome by the Church. During the proceedings of his inquisition, Galileo was treated with respect and was never imprisoned. In fact, he stayed at the house of the Tuscan ambassador to the Vatican.
It was only during the final attempt that Galileo admitted that he supported the Copernican theory. Post the inquisition, Galileo was convicted of heresy and put under house arrest.
He spent the first six months at the palace of Ascanio Piccolomini, after which he moved to a villa near Arcetri, in the hills above Florence, where he spent the last few days of his life.
In his last days, Galileo worked on his final book 'Two New Sciences,' which summarized all of his discoveries made on the science of motion and strength of material. The book was printed in Holland in 1638.
Personal Life & Legacy
Galileo was in a relationship with a Venetian woman named Marina Gamba. The couple was blessed with three children; two daughters named Virginia and Livia; and a son named Vincenzo.
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Both the daughters were enrolled at the convent of ‘San Matteo’ in Arcetri, where they lived for the rest of their lives. They became nuns, while Vincenzo took up the profession of a lutenist.
Galileo left for the heavenly abode on January 8, 1642, after suffering from fever and heart palpitations.
Ferdinando II, the Duke of Tuscany, wished to bury Galileo’s body next to his ancestors in the main body of the Basilica of Santa Croce. However, he was unable to do so as the then Pope and his nephew Cardinal Francesco Barberini condemned Galileo on account of heresy. His body was thus buried in a small room next to the novices' chapel.
In 1737, his mortal remains were reburied in the main body of the basilica. A monument, present till date, was erected in his honor. During the transfer, three fingers and a tooth were removed from his remains. One of these fingers is currently on exhibition at the ‘Museo Galileo’ in Florence, Italy.
It was only in the 20th century that several Popes acknowledged the great work and contribution of Galileo in the field of astronomy. For playing a major role in the scientific revolution, Galileo earned the nickname ‘Father of Modern Science.
A number of things have been named after him, including the Galilean moons of Jupiter, the Galileo spacecraft, Asteroid 697 Galilea, the proposed Galileo global satellite navigation system, and Galilean transformation, the change between inertial systems in classical mechanics. In addition, the International Year of Astronomy collector's coin features a picture of him.
Galileo has been honored in popular culture. There are numerous plays, novels, and movies that have depicted his life and scientific philosophy.
He is known as the ‘Father of Modern Science’ for playing a major role in the scientific revolution.
His heliocentric view of the solar system contradicted with the views of the Roman Catholic Church which believed that the earth was stationary.
This great scientist, with the help of his telescope, discovered that the Moon had uneven and rocky surface, dismissing the general Aristotelian belief that it was a perfect sphere.
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