Galileo Galilei

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Galileo Galili was an Italian astronomer who is famous for his many contributions to astronomy and physics. He was born February 15, 1564 in Pisa, Italy and he Died on January 08, 1642 in Arcetri, Italy. Through his life Galileo was hated by the church for his beliefs which were contradictory to the church. He proved theories long forbidden, created formulas, discovered more about space than anyone had for a long time, and created his own theory that changed the world forever.

In Galileo's early years, Galileo watched the stars and planets at night. The Catholic church and most people believed that the Earth was the center of everything and the sun, planets and stars revolved around it. In reality the Earth and all the planets revolve around the sun. But no one dared to say this. While Galileo was watching the stars he noticed the moons around Jupiter and stars moving. This is what lead Galileo to believe the truth. The church was wrong.

To Learn And To Teach


In 1581 Galileo enrolled at the University of Pisa as a student of medicine. However, Galileo's mathematical interest lead him to seek to change topics in school but financial difficulties caused him to leave before he got his degree in 1885.


After the University, Galileo spent 3 years searching for a teaching job in vein. He was more successful in mathematics and geometry by producing two treatises (Papers) on balance and center of gravity. Galileo's fame grew on as a mathematician and he eventually got a job at the University of Pisa in 1589. In his teaching years Galileo gained a reputation as a controvert to normal teachings that would become famous later in his lifetime.

A Mathematician By Right

Free Fall

Shortly after his declaration of faith, Galileo wrote a letter to Father Paolo Sarpi which stated the law of free fall which is s = 1/2(gt2). This mathematical formula was a major breakthrough in math because of its significance. This law stated the speed of an object if gravity was the only factor affecting it. To this day, this law has proven accurate.

Other Equations

Galileo's study in free fall was only one kind of equation or formula. Also, Galileo was not the only famous mathematician who developed a formula, there was also Albert Einstein and Isaac Newton.


In 1609 Galileo began to study the moon, stars and planets in great detail. Over the course of the next couple months Galileo's studies lead him to amazing discoveries about the mountains on the moon, the moons circling Jupiter and many stars. On March 12, 1610, Galileo's discoveries were published in Venice under the title Sidereus Nuncius.

How To Kill A God

Copernicus, Rome, Sunspots

In 1604 Galileo announced he was a Copernican. He said that a new star that had recently appeared supported the doctrine of Copernicus. In 1583 a friend of Galileo got Galileo interested in Archimedes. This interest lead him to further his research into the Copernican theory. In 1611 Galileo visited Rome. The next year Galileo's Discourse on Bodies in Water was published despite the church denying the idea. This lead the church to pay strong attention to Galileo. In 1613 Galileo published his observations of sunspots. This resulted in controversy towards Galileo because a couple years ago another mathematician had published his observations on sunspots which were very different to Galileo's observations.

God Begins To Die

When he was in Rome, Galileo was determined to fight for the Copernican theory despite underhanded resistance from the Church. Eventually the church won and Galileo was not allowed to represent the Copernican theory in any way. But this near disaster to the church resulted in a large loss of faith towards god. Over the course of a couple years Galileo earned the right to represent Copernicus under his own name. This allowed him to continue to work on his greatest contribution yet.

Dialogue vs. Church

The Dialogue

In 1630 Galileo finished his book, the dialogue, after getting permission from the pope. But the pope did not realize the implications of the dialogue. The dialogue carried the idea that the sun was stationary and the Earth revolved around it, a much hated idea by the church.

The Catholic Church

Over the years the Catholic church had resisted Galileo's ideas which defied their own beliefs. Galileo was a friend of a couple popes' and several religious leaders but when Galileo went along with the dialogue all of them turned against him in desperation to save their faith. Underhanded resistance went from sending rude letters and trying to trick his publishers and supporters to death threats and illegal interruptions of his research that possibly included murder.

Heliocentric Theory

The forbidden heliocentric theory was suggested by people before Galileo. Copernicus was the one who got it into Galileo's head but Archimedes might have started the idea and many others had their hand in it all over the world. This idea contradicted the idea of the geocentric theory, which was much loved by the church. The theory declared that everything revolved around a planet in a solar system, including the sun.

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For more on the heliocentric theory click here.


The dialogue was resisted to be published by Rome, but the plague (Bubonic Plague A.K.A. The Black Death) caused communication between Florence and Rome to be severed so Galileo sent the book to Florence where it was published before the church could warn Florence to do otherwise. For more on the plague click here

Exile And Death

Trial By Church

The dialogue was practically considered an act of war by the Church and Galileo was summoned to the inquisition for trial in 1633. The crime was hearsay of the highest degree. He was to be executed by guillotine but at the last minute he was allowed to live in exile.

The Oddest Exile

In reality, Galileo's "imprisonment" was merely him living in a couple different houses with guards making sure he did not spread his hearsay. He was not allowed to exit the house without being guarded and anyone who visited him was threatened not to spread any of Galileo's words or they and their family would be beaten to death. Galileo was forced to live his life in these "safe houses" until he died so he could cause the church no more trouble. All of this because Galileo turned his telescope to the sky and saw the truth. The church was wrong.

Old Age

Through his years of imprisonment Galileo continued writing his books, some of which were published in other countries. By this time he had become blind and relied on friends to write his books.


In His Lifetime

Some of Galileo's accomplishments include the Dialogue, the formula for free fall and the publication of his many astronomical discoveries in the Sidereus Nuncius.

Post Death Awards

Galileo's investigation into the Copernican theory and discovery of several of Jupiter's moons (Io, Europa, Ganymede and Callisto) lead scientists to name those moons the Galilean moons. Also, the first spacecraft to orbit Jupiter was named the Galileo spacecraft. Also, the Gal (unit of acceleration) was named after Galileo. And Asteroid 697, Galilea is named after Galileo.


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