Galileo Galilei
1564 - 1642

Galileo was born in 1564, the year of Michelangelo's death and Shakespeare's birth. Because of this fact, some say that Galileo was destined to do great things. Galileo's father, Vincenzio Galilei was a musical theorist, who supported his family by selling cloth. Galileo's father, wanting him to prosper more so than himself, strongly encouraged him to attend the University of Pisa to study medicine.

While studying at the university, bored of medicine, he discovered something that fascinated him. Walking through the halls, he glanced in at a class so entranced with the lecturer that he was impelled to listen and watch. As he listened to the geometry lesson, Galileo realized what he really wanted to study. He kept studying medicine at the persistence of his father, but while still in his first year, convinced his father to allow him to study math with a private tutor. Eventually, he quit studying medicine to focus his interests in math. In his time, the study of math, astronomy and science were very closely related. These studies led him to many profound discoveries.

In 1582, while praying in a chapel, Galileo observed a lamplighter lighting the chandeliers. The lamplighter would pull the lamps nearer him with a rod, and after lighting them, let them swing until they hung in place. Timing the swings against his own heartbeat, Galileo discovered the law of pendulum. No matter how wide an arc the lamps made, the time it took to complete a cycle, swinging from one side to the other was the same, even as the size of the arc decreased.

In 1589, at age 25, Galileo was given the position of lecturer in math at the University and was selected as the Chair of Mathematics. During this time, he began to study the works of Aristotle. Challenging some of the ideas of the great scientist, Galileo began to experiment on his own. Many of his colleagues thought him mad and ignored his studies. Wanting to disprove Aristotle's theory of falling objects, Galileo devised an experiment. In order to gain the respect of his colleagues, he heavily advertised the upcoming experiment. With the aid of two of his students, Galileo took two metal balls, one of which weighed ten times as much as the other. Dropping them from the top of the Leaning Tower of Pisa, his students timed each of the balls' falls. When Galileo's theory was proven correct, that no matter the weight, the balls would fall at the same rate and land at the same time, his colleagues still did not believe him, accusing him of using magic to alter the falls.

A better position was available, and in 1592, he left Pisa and became professor of mathematics at the University of Padau near Venice. There, he remained until 1600 when, at age 45, he was asked by Grand Duke of Tuscany, Cosmo II to be the Chief Mathematician in his court in Florence.

In 1609, Galileo revised the spyglass to create a telescope, improving magnification from 9 times to 32. With this new creation, Galileo began his study of the ever-mysterious heavens. He discovered many things with his telescope, such as mountains on the moon, and moons around Jupiter. In 1610, Galileo's first scientific book The Starry Messenger was published, describing what he had seen. With his new findings, Galileo also began to compare the theories of Ptolemy (which stated that all planets, including the sun orbited the Earth) and Copernicus (which stated that the sun was the center of the universe). Galileo's findings supported Copernicus' theory, which was against the beliefs of the church. In 1616, Galileo was called to the Roman Inquisition and made to promise to no longer publish or defend the Copernican theory.

After two more calls to the Roman Inquisition, Galileo was convicted of heresy and incarcerated. Shortly after his incarceration, his sentence was lessened to house arrest. For the last 8 years of his life, Galileo lived in his estate at Arcetri. Still studying mathematics, and with the aid of several faithful students, he wrote more on his studies of motion. Forbidden to publish, at least one known book(Discourses on Two New Sciences) was smuggled from the country to be published elsewhere. In 1642, at age 78, having led a full life of discovery, Galileo died, apparently of natural causes.

Contributed by Lindsay Eastridge


  2. Calinger, Ronald (1995), Classics of Mathematics.
  3. Kline, Morris (1990), Mathematical Thought from Ancient to Modern Times.
  4. Reimer & Reimer (1992), Historical Connections in Mathematics

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