Biography of Galileo Galilei

Galileo Galilei was the pioneer of the experimental scientific method and the first to use a reflex telescope, with which he made important astronomical discoveries.

Galileo eventually became one of the most important astronomers of the Renaissance because of his special interest in mathematics.Galileo Galilei

He begins to study gravity, the oscillations of the heavy pendulum and develops the heart rate monitor.

Galilei is mainly known for:

  1. Defend, through the scientific method and at the risk of his own life, the heliocentric theory of Nicolas Copernicus.
  2. Contribute to the development of the telescope.
  3. Discover Jupiter’s four main satellites (now called the”Galilean satellites” in his honour).

Where Galileo was born

Galileo Galilei was born in Pisa (Italy) on 15 February 1564. He was an astronomer, physicist, mathematician, Italian philosopher, and engineer.

Renowned for being one of the most emblematic and influential figures in history, for his work in science and knowledge. He was the son of Giulia Ammannati and Florentino Vincenzo Galilei.

In 1574, when his parents moved to Florence, he was in charge of a religious neighbor named Jacobo Borhini.

The little boy entered the convent of Santa María de Vallombrosa, where he received a pious formation and thought of joining the religious life.

His father was very skeptical and took advantage of the fact that Galileo had an infection in his eye and took him out of the convent, citing a lack of care.

What music was heard in the time of Galileo Galilei


The University of Pisa

By 1581, Galileo entered the University of Pisa, where he enrolled as a medical student by his father’s will.

Galileo would have discovered the isochrony of the pendulum by observing the movements of a lamp in the cathedral of Pisa.

In spite of continuing his studies, Galileo was not inclined towards the medical profession, and in 1583 he interrupted his medical studies.

He moved to Florence to study Euclid’s geometry under the direction of Florentine court mathematician Ostilio Ricci.

He left the university without having obtained any degree, although with a good knowledge of Aristotle.

That was the moment when Galileo realized that his true passion was science, especially philosophy and mathematics.

The return to Florence

In 1585 he returned to Florence and spent several years studying mathematics. Galileo was also interested in philosophy and literature, where he gave priority to Ariosto over Tasso.

His first work on the barycentre of bodies and the creation of a hydrostatic balance for the determination of specific weights dates from this period.

Two contributions in the line of Archimedes, whom Galileo would not hesitate to call superhuman.

He also began by demonstrating many theorems about the center of gravity of certain solids, continuing his studies on the oscillations of the heavy pendulum and invented the pulsometer.

This device helps to measure the pulse and provides a time scale, which did not exist at that time.

In 1588, he was invited by the Florentine Academy to present two lessons on”the form, place, and dimension of Dante Alighieri’s hell”.

In 1589 he began to work as a mathematics professor at the University of Pisa. Three years later he moved to Padua to teach geometry, mechanics, and astronomy at the university until 1610.

The Inquisition did not have much power in Padua and this gave it more freedom to investigate.

Professor Galileo

At the same time as his activities, he looked for a job as a professor at a university and met great people.

Like Jesuit Father Christopher Clavius, excellence in mathematics at the Pontifical College, and with the mathematician Guidobaldo del Monte, who recommended Galileo to the Duke Ferdinand I of Medici, to be appointed to the chair of mathematics at the University of Pisa.

Between 1590 and 1591, Galileo Galilei discovered the Cycloid and used it to drawbridge arches.

He also carried out experiments on the fall of bodies and wrote his first mechanical work, entitled”Motu”.

In 1592 he moved to the University of Padua and worked as a professor of geometry, mechanics, and astronomy until 1610. There he invented the calculus compass with which to solve practical mathematical problems.

The marriage of Galilei

In 1599, at the age of 35, he began his love affair with Marina Gamba, 21, whom he met on one of his frequent trips to Venice.

Marina Gamba moves to Galileo’s house to live with him, but without marrying him. With her, he had two daughters and one son: Virginia (1600), Livia (1601) and Vincenzo (1606).

Marina Gamba married Giovanni Bartoluzzi in 1613, having already taken care of her daughters and son Galileo before.

Later his two daughters will enter a convent, probably because of Galileo’s financial difficulties to guarantee them a sufficient dowry for a marriage suitable for their status in the Medici Court.

His son, on the other hand, will enter the service of the Grand Duke of Tuscany.

First discoveries of Galilei

The year 1604 was successful for Galileo Galilei, as in July he tested his water pump in the garden of Padua; in October, he discovered the law of uniformly accelerated motion which he associated with a law of erroneous velocities; and in December, he began his observations of a nova star.

In February 1605 he published: “Dialogo de Cecco da Ronchitti da Bruzene in Perpuosito de la Stella Nova” together with Girolamo Spinelli.

During these years he developed tools such as the thermoscope, as well as continued studying astronomy. Its greatest advance was the construction of a telescope that was able to avoid deforming the objects and achieve 6x magnification.

In 1606, Galileo Galilei built his first Thermoscope, the first device in history to objectively compare the level of heat and cold.

That same year, he and two of his friends contracted an infectious disease from which only Galileo survived, which is why he remained crippled with rheumatism for the rest of his life. Over the next two years, he studied the structures of the magnets.

The famous Telescope

In May 1609, he received a letter from the Frenchman Jacques Badovere, one of his former students, confirming an insistent rumour: the existence of a telescope that allowed him to see distant objects.

This telescope would have made it possible to see stars invisible to the naked eye by now. With this unique description, Galileo built his first telescope.

Unique in his time, he was able to obtain a straight image thanks to the use of a divergent lens in his eyepiece, and this invention took an important turn in his life.

Galileo Galilei continued to develop his telescope and in November of that same year, he made an instrument that increases twenty times, placed it in the sky observing the phases of the Moon with mountains and craters discovering the four major satellites of Jupiter, later published his book”The messenger of the stars”.

The stars of Jupiter

On January 7, 1610, Galileo made a major discovery: he noticed three small stars on the periphery of Jupiter. But after observing many nights, he discovered that there are four of them and that they revolve around the planet.

On 4 March of that year, he published his discoveries in Florence as part of”The Messenger of the Stars”. On July 25th, he also directed his telescope towards Saturn and discovered its strange appearance, then found a way to observe the Sun on the telescope and discovered sunspots.

The telescope changed his life. He improved his economic and research life. He was able to build one with up to twenty magnifications with which he could observe the lunar phases and the surface of the star.

The telescope allowed him to observe the Milky Way, the rings of Saturnos, stars and other stars. He discovered the satellites orbiting Jupiter.

His discovery allowed him to affirm that all celestial bodies do not revolve around the Earth. Not everyone (like satellites) revolves around the Sun either, as Copernican theories claimed. His theories were very successful.

The phases of Venus

Galileo Galilei continued to discover things, and in September 1610, he discovered the phases of Venus, which was for him, a new test of the truth of the Nicolas Copernicus system.

Galileo begins to convince everyone and the defenders of geocentric theory become his greatest enemies. They begin to attack him and reject his claims. In 1611, Cardinal Roberto Belarmino ordered the Inquisition to discreetly investigate Galileo.

Invitation to Rome

On March 29, 1611, he was invited by Cardinal Maffeo Barberini to present his discoveries to the Pontifical College of Rome and the Academy of the Wildcats. Galileo remained in the pontifical capital for a full month, during which time he received all the honors.

By April 24 of that same year, the Roman College confirmed to Cardinal Roberto Belarmino that Galileo’s observations were accurate.

On 4 June, Galileo Galilei returned to Florence with the aim of continuing his investigations.

For years, the astronomer has proved difficult to attack scientifically. In 1616, the Inquisition and Pope Paul V censured Copernican theories as being considered foolish, absurd and heretical.

You are asked to present your thesis as a hypothesis and not as a proven fact, which causes you discomfort.

This situation caused his health to deteriorate. However, Galileo continued to defend his theses for years.

The astronomer was the highest representative of the Roman intellectuals who rebelled against the conformism of the Jesuits, their main opponents.

In March 1628, Galileo Galilei became seriously ill but managed to recover after a while to continue his work.

Galileo’s heretic

On February 21, 1632, he published in Florence his dialogue of the”Massimi Sistemi”.
The publication of his work in the vulgar language upset the Church, as this allowed the people on the street to have access to it. His work, accused of being heretical, had passed the Inquisition’s censorship and was therefore in a bad place.

He was summoned to Rome in 1632 when he was 68 years old. He was threatened with torture to confess and renounce his ideas and be sentenced to life imprisonment. The pope commuted the prison but ordered house arrest for life.

In February 1633 he travels to Rome to testify before the court of the Inquisition but is allowed to reside in the palace of the ambassador of Tuscany, although he must remain isolated.

From 12 to 30 April he was formally interrogated by the court and, after several painful events, abjured his mistakes in a ceremony held in the church of Santa Maria Sopra Minerva.

The house arrest

He will then be placed under house arrest at his residence in Arcetri, near Florence, where he will serve his sentence.

In the same year, 1633, Galileo Galilei was sentenced to life imprisonment with house arrest. The other part of the ruling ordered the burning of all copies of some of his books and the sentence against him was to be read publicly in all universities.

His health is progressively worsening. In 1634 he requested permission from the ecclesiastical authorities to be treated by the doctors in Florence but was refused permission, with the warning that if he asked for another permit again, he would be imprisoned.

That same year his first daughter, Virginia, died in a convent near Arcetri, where she professed her habits under the name of Sister Maria Celeste, and with whom she had corresponded regularly since 1623.

Despite these circumstances and the progressive loss of vision, Galileo continues its activities.

In 1638 he completely lost his sight and made a request for his sentence to be lifted and he was released, a request which was denied, but he was allowed to settle in his home in Florence so that he could be treated medically for his ailments.

The blind Galileo

His last book was published in 1638, in which he discussed and improved his early studies in movement and the principles of physics.

This book began a slow journey that would later follow none other than Isaac Newton. Galileo lost his sight before his last book was published.

Shortly before he died, he had to recant and deny the truth in order not to end up burned at the stake. Some historians say that in a low voice, just after he abjured, he muttered the famous phrase: “Eppur si muove” (and yet, it moves) referring to the movement of the Earth around the sun.

Galileo’s death

Galileo Galilei died on January 8, 1642, in Arcetri, at the age of 77, his body was buried in Florence on January 9.

His remains are buried in the well-known Basilica of the Holy Cross of Italy.
His tomb is undoubtedly a great allegory to his own life: Father of modern astronomy”, Father of modern physics and Father of science.

In this impressive church, the one of Santa Croce you can visit other famous tombs such as those of Machiavelli, Lorenzo Ghiberti, Michelangelo or the Tomb of Danti Aligherio.

How to get to the cemetery where Galileo Galilei is located

To find out which cemetery Galileo Galilei is buried in and how to get to the site you have the following helpful information to visit Galileo Galilei.
Name of the cemetery: Basilica of the Holy Cross
Address: Piazza di Santa Croce, 16, 50122 Firenze FI, Italy

A great book I recommend is this.

Who Was Galileo?
  • Sin descripción
  • Patricia Brennan Demuth, Who Hq
  • Publisher: Penguin Workshop
  • Edition no. 0 (02/05/2015)
  • Pasta blanda: 112 pages

What Galileo Saw With His Telescope

What are the works of Galileo Galilei?

  1. 1586:La Bilancetta (posthumously published).
  2. 1590: De motu.
  3. 1606: The operations of geometric and military compasses.
  4. 1600: Le meccaniche.
  5. 1610: Sidereal Messenger, Siderus nuncius.
  6. 1615: Letter to Mrs. Cristina de Lorena, Grand Duchess of Tuscany (published in 1636).
  7. 1616: Speech of the flow and reflux of the sea.
  8. 1619: Discorso delle comete (published by Mario Guiducci).
  9. 1623: Il. Saggiatore.
  10. 1632: Dialogue on the two maximum systems of the world, Dialogue on the two mass systems of the Ptolemaic and Copernican mode.
  11. 1638: Speech and Mathematical Demonstration, in return to two new sciences, Discorsi e dimostrazioni matematiche, intorno a due nuove scienze attenenti alla meccanica & i movimenti locali.

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