Galileo Galilei

Age of Revolution

Galileos Beginning

Galileo was an Italian physicist and astronomer. He was born in Pisa Italy on February 15, 1564. Vincenzo Galilei was Galileo's father and he was a well known musician. He decided that he wanted his son to become a doctor.

How He Started

In 1581 Galileo was sent to the University of Pisa to study medicine. While he was a student at the university he discovered that he had a talent for mathematics. He was able to convince his father to let him leave the university to become a tutor in mathematics. Then later he became a professor of mathematics.

Galileos First invention

In 1609 Galileo he heard about the invention of the spyglass. The spyglass was a device that made far away objects seem close. Galileo used his knowledge in mathematics and technical skills to improve the spyglass and build the first telescope.

Important Things Discovered While Using Telescope

Later the same year of the invention of the telescope, He became the first person to look at the moon through a telescope and it was his first astronomy discovery. He found out that the moon was not smooth but it was mountainous and pitted just like Earth. He also used the telescope to discover the four moons circling jupiter. he used it to study Saturn, to observe the phases of Venus, and also to study sunspots on the Sun.

What It Lead To

Galileo's observations strengthened his belief in Copernicus' theory that Earth and all other planets revolve around the Sun. Most people in Galileo's time believed that the Earth was the center of the universe and that the Sun and planets revolved around it.

What Galileo Believed in

The Catholic Church which was very powerful and influential in Galileo's day strongly supported the theory of a geocentric, or Earth-centered, universe. After Galileo began publishing papers about his astronomy discoveries and his belief in a heliocentric or Sun-centered Universe he was called to Rome to answer charges brought against him by the Inquisition (the legal body of the Catholic Church).

What the Church Thought About Galileo's Idea

Early in 1616 Galileo was accused of being a heretic or a person who opposed Church teachings. Heresy was a crime which people were sometimes sentenced to death. Galileo was cleared of his charges of heresy but was told that he should no longer publicly state his belief that Earth moved around the Sun.

Did Galileo Listen to the Church? (I Think Not)

Galileo continued his study of astronomy and became more and more convinced that all planets revolved around the Sun. In 1632 he published a book that stated among other things that the heliocentric theory of Copernicus was correct.

Galileos End

Galileo was once again called before the Inquisition and this time he was found guilty of heresy. Galileo was sentenced to life in prison or jail in 1633. Because of his age and poor health he was allowed to serve his imprisonment under house arrest. Galileo died on January 8, 1642.


Galileo was the best astronomer in his time period and spent most of his life trying to convince the church that all planets revolve around the sun. In the end he was right but he was still accused of being a heretic.