Galileo Galilei, 1564 - 1642, Tuscany, Italy
Mathematician, Astronomer, Natural Philosopher.

Galileo was the eldest son of Vincenzo and Giulia. His brother was Michelangelo, not the artist of the Sistine Chapel paintings.

Galileo attended a monastery school near Florence and in 1581 he was enrolled in medicine at the University of Pisa. This was his father's preference because he wanted to be sure his son would have a secure lifetime income. Nevertheless, after experiencing the boredom of anatomy as it was understood at the time by the Greeks, and with the help of Rici, a recognized mathematician, Galileo's father agreed that he could study mathematics and drop medicine, and Rici also offered to tutor Galileo. No doubt he could see the potential there.

Galileo Galilei

This allowed Galileo to concentrate on Euclid's geometry, "The Elements".
Rici introduced him to the work of Archimedes, and the laws of motion, which lead to the pendulum as a means of measuring time. This inspiration was supposed to have arisen from watching a candle swinging in the church. For small amplitude the pendulum was quite constant, enabling him to measure his heart rate.

When he finally left the university, it was without a degree!
It would seem he did not have time to study the mathematics as in the syllabus.

Now he needed to find a way to earn a living and decided to take in boarders and teach them mathematics. This gave him time to study the work of Archimedes and Aristotle.

According to Aristotle, an object that is heavy will fall faster than an object that is lighter, but Galileo disputed this theory. He was of the opinion that these two objects would fall at about the same rate. To support this claim he dropped objects from the Leaning Tower of Pisa.

Leaning Tower of Pisa

The teachings of Aristotle were generally accepted in universities in Europe, and Galileo's assertions were very unpopular. His contract with the university where he was teaching was canceled.
A year later, he was appointed as the chair of mathematics at the University of Padua, where he spent the next 18 years of his life.

Galileo had many areas of interest and made innovative discoveries in a diverse range of studies.
Determining the center of gravity of distributed objects had been an area of study for some time, and Galileo was able to shed some light on this subject.
There was also a lot of interest in the way pulleys worked, as well as how heavy loads could be lifted with little effort by using them.

Cannonball Parabola

The parabola was of particular interest to the military. The parabola is the path of a cannonball approximately, and although it looks complicated Galileo could show that it consisted of two motions combined. There was a constant sideways motion and at the same time there was a straight up and down motion.

In 1609 there was a sudden change in the life of Galileo. He discovered that a device had been made in the Netherlands which could make distant objects look much larger. It was a device that used glass lenses. After verifying that it worked, in a very short time, he was grinding his own lenses and was able to make a refracting telescope with a magnification of up to 20 times.

Refracting Galileo Telescope

As a result of showing the instrument to the university Senate, his position was made a life tenure, his salary was doubled, and his interest in astronomy intensified.

By 1610 he had observed 4 satellite moons of Jupiter, which he cleverly named after the Medici family, who then very graciously appointed him as the mathematician and philosopher of the grand duke of Tuscany.

Searching the skies

In his new and exalted position, Galileo had more time to explore the skies, discovering aspects of the planets and their motions to convince him that Copernicus was right, the sun was at the center and not the earth.

However, his discoveries led him to personal difficulties because the heliocentric theory was in conflict with parts of Scripture. As well, many of the Fathers of the Church complained to the Inquisition. Galileo was warned and told "not to hold, teach, or defend" the Copernican theory.

Galileo had an audience with Pope Urban VIII, a friend, and admirer, in Rome. He departed from Rome with the mistaken impression that he had permission to publish his book, provided he did not treat the theory of Copernicus. However, his book proved to be clearly provocative.

The book, "Dialogue Concerning the Two Chief World Systems, Ptolemaic & Copernican", was presented in 1632 to the Florentine censor, professing that the book was hypothetical.
Nevertheless, Galileo was summoned to Rome in 1633, to confront the Inquisition.

Presenting his arguments to the Inquisition

He was convicted of heresy, and condemned to life imprisonment.

That sounds harsh, but Galileo lived initially in a palace, then in a villa with the archbishop of Siena, then finally with his daughter. He died while still working on another book.

Click here for a reckless genius.

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