Galileo Galilei

The great scientist Galileo Galilei changed the universe. At least, he changed the way we human beings conceive of the universe. Galileo was an all-around genius; in his lifetime, he'd prove an accomplished inventor, writer, philosopher, astronomer, painter, and musician.

Coming of Age

Galileo was born near Pisa on February 15, 1564. Vincenzo Galilei, his father, was a wool trader and famous musician, and Galileo had five younger siblings. The Galilei family moved to Florence when Galileo was 8, and Galileo’s father sent him to a Jesuit monastery when he was 11. At age 15, Galileo decided to become a monk. His father, however, wanted him to go into medicine, and he promptly withdrew his son from the monastery. Galileo would further his education at the University of Pisa. Initially, he tried to please his father by becoming a medical student. In time, however, he found himself increasingly drawn to the fields of mathematics and philosophy.

University Days

galileo.jpg It was as a medical student that Galileo first made waves within the wider scientific community. One day, he was inside the university’s cathedral and made the intriguing observation that the swinging chandeliers all moved at the same rate no matter their size. He even timed their swings using his pulse. Inspired, Galileo began studying objects in motion – pendulums in particular. This inquiry led him to conclude that objects of all masses fall at the same rate. Since at least the days of Aristotle, people had believed that heavier objects fell faster than lighter objects. Incidentally, an oft-repeated story is that Galileo dropped two weights from the top of the Leaning Tower of Pisa to prove this theory. However, though Galileo did muse about such an experiment in writing, it’s unlikely that he actually attempted it. Additionally, while studying the motion of objects, he found that whenever one is thrown into the air, the path that it takes is a parabola.

Professor and Father

Galileo left the University of Pisa without obtaining a degree and found employment as a math tutor. Then, despite the fact that he lacked a diploma, he became a mathematics professor at the University of Pisa in 1589. Reportedly, Galileo was sometimes abrasive when dealing with colleagues there. Three years later, he would take a new position teaching math at the University of Padua, and he stayed at that school until 1610. What's more, between 1600 and 1606, Marina Gamba, Galileo’s mistress, would bear their three children. Galileo, a Catholic and a leading citizen, did not publicly admit paternity during his lifetime. His two daughters would eventually enter the convent, and his son would become a musician; he played the lute.

Astronomer Extraordinaire

It was as an astronomer that Galileo made his greatest contributions to science. In 1609, Galileo found out that scientists in Holland had just invented the telescope, which was then called the “spyglass.” Galileo decided to create one of his own; he even ground his own lenses to do so. The telescope that he devised could magnify objects up to nine times. To put that into context, the most powerful spyglasses at that time could only magnify objects approximately three times. Galileo used his telescope to make a number of significant discoveries, including the moon’s craters and Jupiter’s four largest moons. He may even have been the first to see Neptune. Further, Galileo noticed that the way Venus appeared to be lit varied. These different formations of light, called “phases,” led him to deduce that Venus must always be closer to the sun than Earth. Otherwise, the phases of Venus would not be visible from Earth. Galileo realized, as he explained in a 1613 publication, that the phases of Venus were thus evidence of the Copernican theory. Astronomer Nicolaus Copernicus had proposed in 1543 that the sun never moved and that the planets revolved around it at speeds and distances that remained consistent.

Clashes with the Catholic Church

Galileo’s advances in astronomy earned him widespread renown, and city officials in Florence named him court mathematician. It was in this position, however, that he first ran afoul of the Catholic Church. Church officials objected to Galileo’s championing of the Copernican view of the galaxy; the Church maintained that God had created the Earth as the center of the universe. In 1616, the Church officially and expressly prohibited Galileo from advocating the Copernican position. Galileo obeyed that command until 1632, the year that he published “Dialogue Concerning the Two Chief World Systems.” In that landmark book, he relays a fictional conversation between two individuals: One man advocates the Copernican theory, and the other tries to dismiss it. Throughout this work, Galileo strove to support the Copernican theory mathematically. He believed that Catholic leaders would accept the book’s propositions if they were backed by mathematical formulas. Galileo was wrong: The Church ordered him to appear at Rome’s Inquisition, and he was found guilty of heresy and sentenced to life in prison. The Church later softened this sentence, and Galileo was given a punishment of house arrest for life. To escape the death penalty, however, the astronomer was forced to publicly withdraw his support for the Copernican theory.

Home Confinement

Galileo spent the rest of his life, which amounted to nine years, in his home in Arcetri, a region of central Italy. In the late 1630s, he started to go blind. That condition did not stop him from writing, however, and he published “Discourses Concerning Two New Sciences” in 1638, a book focusing on mechanics and motion. Galileo also worked on a pendulum clock, the first such clock ever. Pendulum clocks would have a major effect on society in that they would allow people to measure and mark time accurately and uniformly. Galileo Galilei died in Arcetri on January 8, 1642; he was 77 years old.

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