Galileo Galilei

1. Born on February 15, 1564, in Pisa, Italy, Galileo Galilei was a mathematics professor who made pioneering observations of nature with longlasting implications for the study of physics. He also constructed a telescope and supported the Copernican theory, which supports a suncentered solar system. Galileo was accused twice of heresy by the church for his beliefs, and wrote books on his ideas. He died in Arcetri, Italy, on January 8, 1642. .....

Early Life

2. Galileo Galilei was born on February 15, 1564, in Pisa in the Duchy of Florence, Italy. He was the first of six children born to Vincenzo Galilei, a wellknown musician and music theorist, and Giulia Ammannati. In 1574, the family moved to Florence, where Galileo started his formal education at the Camaldolese monastery in Vallombrosa.In 1583, Galileo entered the University of Pisa to study medicine. Armed with high intelligence and talent, he soo .....

Academic Career

3. Galileo continued to study mathematics, supporting himself with minor teaching positions. During this time he began his twodecade study on objects in motion and published The Little Balance, describing the hydrostatic principles of weighing small quantities, which brought him some fame. This gained him a teaching post at the University of Pisa, in 1589. There Galileo conducted his fabled experiments with falling objects and produced his manuscrip .....

Controversial Findings

4. In 1604, Galileo published The Operations of the Geometrical and Military Compass, revealing his skills with experiments and practical technological applications. He also constructed a hydrostatic balance for measuring small objects. These developments brought him additional income and more recognition. That same year, Galileo refined his theories on motion and falling objects, and developed the universal law of acceleration, which all objects in .....

Reaction by the Church

5. Church reaction against the book was swift, and Galileo was summoned to Rome. The Inquisition proceedings lasted from September 1632 to July 1633. During most of this time, Galileo was treated with respect and never imprisoned. However, in a final attempt to break him, Galileo was threatened with torture, and he finally admitted he had supported Copernican theory, but privately held that his statements were correct. He was convicted of heresy and .....

Personal Life

6. In 1600, Galileo met Marina Gamba, a Venetian woman, who bore him three children out of wedlock: daughters Virginia and Livia, and son Vincenzo. He never married Marina, possibly due to financial worries and possibly fearing his illegitimate children would threaten his social standing. He worried the two girls would never marry well, and when they were older, had them enter a convent. His sons birth was eventually legitimized and he became a succ .....

Law of the Pendulum

7. At age twenty, Galileo noticed a lamp swinging overhead while he was in a cathedral. Curious to find out how long it took the lamp to swing back and forth, he used his pulse to time large and small swings. Galileo discovered something that no one else had ever realized: the period of each swing was exactly the same. The law of the pendulum, which would eventually be used to regulate clocks , made Galileo Galilei instantly famous.Except for mathem .....

Mathematics

8. To earn a living, Galileo Galilei started tutoring students in mathematics. He did some experimenting with floating objects, developing a balance that could tell him that a piece of, say, gold was 19.3 times heavier than the same volume of water. He also started campaigning for his lifes ambition: a position on the mathematics faculty at a major university. Although Galileo was clearly brilliant, he had offended many people in the field, who woul .....

Dantes Inferno

9. Ironically, it was a lecture on literature that would turn Galileos fortunes. The Academy of Florence had been arguing over a 100yearold controversy: What were the location, shape, and dimensions of Dantes Inferno Galileo Galilei wanted to seriously answer the question from the point of view of a scientist. Extrapolating from Dantes line that [the giant Nimrods] face was about as long And just as wide as St. Peters cone in Rome, Galileo deduced t .....

The Leaning Tower of Pisa

10. At the time that Galileo arrived at the University, some debate had started up on one of Aristotles laws of nature, that heavier objects fell faster than lighter objects. Aristotles word had been accepted as gospel truth, and there had been few attempts to actually test Aristotles conclusions by actually conducting an experiment.According to legend, Galileo decided to try. He needed to be able to drop the objects from a great height. The perfect .....

Necessity is the Mother of Invention

11. Galileo Galilei moved on to the University of Padua. By 1593, he was desperate in need of additional cash. His father had died, so Galileo was the head of his family, and personally responsible for his family. Debts were pressing down on him, most notably, the dowry for one of his sisters, which was paid in installments over decades (a dowry could be thousands of crowns, and Galileos annual salary was 180 crowns). Debtors prison was a real threat .....

Spyglass

12. Galileo Galilei was determined to attempt to construct his own spyglass. After a frantic 24 hours of experimentation, working only on instinct and bits of rumors, never having actually *seen* the Dutch spyglass, he built a 3power telescope. After some refinement, he brought a 10power telescope to Venice and demonstrated it to a highly impressed Senate. His salary was promptly raised, and he was honored with proclamations. .....

The Moon

13. If he had stopped here, and become a man of wealth and leisure, Galileo Galilei might be a mere footnote in history. Instead, a revolution started when, one fall evening, the scientist trained his telescope on an object in the sky that all people at that time believed must be a perfect, smooth, polished heavenly bodythe Moon. To his astonishment, Galileo Galilei viewed a surface that was uneven, rough, and full of cavities and prominences. Many p .....

Jupiter

14. Months passed, and his telescopes improved. On January 7, 1610, he turned his 30 power telescope towards Jupiter, and found three small, bright stars near the planet. One was off to the west, the other two were to the east, all three in a straight line. The following evening, Galileo once again took a look at Jupiter, and found that all three of the stars were now west of the planet, still in a straight line.Observations over the following weeks .....

The Starry Messenger

15. Galileo Galilei published his findingsas a small book titled The Starry Messenger. 550 copies were published in March of 1610, to tremendous public acclaim and excitement. .....

Saturn

16. And there were more discoveries via the new telescope: the appearance of bumps next to the planet Saturn (Galileo thought they were companion stars; the stars were actually the edges of Saturns rings), spots on the Suns surface (though others had actually seen the spots before), and seeing Venus change from a full disk to a sliver of light. For Galileo Galilei, saying that the Earth went around the Sun changed everything since he was contradictin .....

Heresy Charges

17. Galileo Galilei was a religious man, and he agreed that the Bible could never be wrong. However, he said, the interpreters of the Bible could make mistakes, and it was a mistake to assume that the Bible had to be taken literally.This might have been one of Galileos major mistakes. At that time, only Church priests were allowed to interpret the Bible, or to define Gods intentions. It was absolutely unthinkable for a mere member of the public to do .....

The Final Trial

18. The following years saw Galileo move on to work on other projects. With his telescope he watched the movements of Jupiters moons, wrote them up as a list, and then came up with a way to use these measurements as a navigation tool. There was even a contraption that would allow a ship captain to navigate with his hands on the wheel. That is, assuming the captain didnt mind wearing what looked like a horned helmet.As another amusement, Galileo start .....

Copernican system

19. In Galileos lifetime, all celestial bodies were thought to orbit the Earth. Supported by the Catholic Church, teaching opposite of this system was declared heresy in 1615.Galileo, however, did not agree. His research including his observations of the phases of Venus and the fact that Jupiter boasted moons that didnt orbit Earth supported the Copernican system, which (correctly) stated that the Earth and other planets circle the sun.In 1616, .....

Death and Legacy

20. Galileo died in Arcetri, near Florence, Italy, on January 8, 1642, after suffering from a fever and heart palpitations. But in time, the Church couldnt deny the truth in science. In 1758, it lifted the ban on most works supporting Copernican theory, and by 1835 dropped its opposition to heliocentrism altogether.In the 20th century, several popes acknowledged the great work of Galileo, and in 1992, Pope John Paul II expressed regret about how the .....