Galileo Galilei: Life, Education, and Scientific Contributions

Early Life and Family Background

Galileo Galilei's father was Vincenzo Galilei, and his mother was Giulia Ammannati. Vincenzo was born in 1520 in Florence. He was a teacher of music and a fine arts enthusiast, as well as an accomplished flute player (O'Connor & Robertson, 2002). While studying music in Venice, Vincenzo conducted a series of experiments to support his musical theories. Galileo's mother, Giulia, was a native of Pescia. She married Vincenzo in 1563 and moved to the countryside near Pisa.

Galileo was the first-born child in the family and spent the early part of his life in Pisa. When he was barely nine years old, his family returned to Florence, his father's hometown (O'Connor & Robertson, 2002). Galileo, however, chose to remain in Pisa for two more years, staying with Muzio Tedaldi, a relation of his mother. Upon reaching the age of ten, he joined his family in Florence, where he was tutored by Jacopo Borghini.

Education and Academic Career

Once Galileo was old enough, his parents sent him to the Camaldolese Monastery at Vallombrosa, located 33 km southeast of Florence. The Camaldolese Order had separated from the Benedictine Order following a split in 1012 and combined the solitary life of a hermit with the strict discipline of a monk (O'Connor & Robertson, 2002). Young Galileo found this way of life very attractive and soon became a novice with the intention of joining the order. However, this did not please his father, who had decided that his eldest son should become a medical doctor. Galileo was called back to Florence, and his hopes of joining the Camaldolese order were abandoned. Back in Florence, he continued his schooling at a school run by the Camaldolese monks.

In 1581, his father sent him back to Pisa to stay with Muzio Tedaldi, and Galileo enrolled in a medical degree at the University of Pisa (O'Connor & Robertson, 2002). Although a medical career held little appeal for him, he regarded his father's wish as natural, given that there had been a distinguished physician in his family in the thirteenth century. He does not appear to have taken his medical studies seriously, attending only courses in his true areas of interest — mathematics and natural philosophy. His mathematics teacher at the university, Filippo Fantoni, also served as the chair of mathematics. During his summer vacations in Florence, Galileo continued to study mathematics independently.

The mathematician of the Tuscan Court, Ostilio Ricci — a former pupil of Tartaglia — taught Euclid's Elements at Pisa in 1582–83, and Galileo attended these lectures. His father Vincenzo encouraged him, whenever he returned to Florence on vacation, to read Galen in order to advance his medical studies (O'Connor & Robertson, 2002). Galileo, reluctant to pursue medicine, repeatedly invited Ricci to his home to meet his father. Ricci attempted to persuade Vincenzo to allow Galileo to study mathematics, given the boy's evident passion for it — something Vincenzo resisted strongly. Eventually, however, Vincenzo relented somewhat and permitted Galileo to study the works of Euclid and Archimedes from Italian translations that Tartaglia had made (O'Connor & Robertson, 2002).

Galileo left Pisa in 1585 without completing his medical degree. He then taught mathematics privately in Florence, and during 1585–86 he received a public teaching appointment in Siena. During the summer of 1586, he taught at Vallombrosa and wrote his first scientific work, The Little Balance, which described Archimedes' methods for finding the specific gravities of substances using a balance. In 1587, he travelled to Rome to meet the Professor of Mathematics at the Jesuit Collegio Romano, sharing his discoveries on centers of gravity — a subject of great interest to Jesuit mathematicians at the time (O'Connor & Robertson, 2002). Although Galileo made a favorable impression on Clavius, he was not granted a position at the University of Bologna; the two men did, however, maintain a correspondence.

In 1588, Galileo received a prestigious invitation to lecture at the Academy in Florence on the dimensions and location of hell as depicted in Dante's Inferno. When Fantoni vacated the chair of mathematics at the University of Pisa, Galileo was appointed to fill the post, with Clavius providing one of his strongest letters of recommendation (O'Connor & Robertson, 2002). He held the chair of mathematics at Pisa for three consecutive years, during which time he wrote De Motu, a series of essays on the theory of motion. Because a professorship in mathematics did not pay enough to support his family or provide dowries for his two younger sisters, Galileo sought more lucrative positions. Upon the recommendation of Guidobaldo del Monte, he was appointed Professor of Mathematics at the University of Padua in 1592, one year after his father's death. This institution is today known as the University of the Republic of Venice (O'Connor & Robertson, 2002).

The Telescope and Astronomical Discoveries

In 1609, Galileo received a letter from Paolo Sarpi describing a spyglass that had been constructed by a Flemish craftsman. Using this instrument, distant objects could be seen with remarkable clarity (O'Connor & Robertson, 2002). Galileo applied his skills as both a craftsman and a mathematician to produce a series of telescopes that far surpassed the optical performance of the original. His first telescope used lenses capable of magnifying objects four times. By grinding and polishing his own lenses, he improved the instrument to a magnification of approximately eight or nine times by the end of 1609. He kept Sarpi informed of his progress, and Sarpi arranged a demonstration before the Venetian Senate. Because telescopes had obvious commercial and military value — particularly for use at sea — the Senate was greatly impressed, and Galileo's salary was increased. He gave the Senate exclusive rights to manufacture his telescopes.

Galileo made numerous astronomical discoveries with his improved instrument, many of which are recorded in his short treatise Starry Messenger. On 25 July 1610, he turned his telescope on Saturn (Pantin, 1999). Saturn appeared to have three bodies, likely because the telescope's resolution was insufficient to clearly reveal the rings; instead, they appeared as lobes on either side of the planet. That same year, Galileo also observed that Venus displayed phases similar to those of the Moon, which indicated that Venus must orbit the Sun rather than the Earth.

References

Eastridge, L. (2002). Galileo Galilei 1564–1642. Retrieved from

O'Connor, J. J., & Robertson, E. F. (2002). Galileo Galilei. Retrieved from

Pantin, I. (1999). New philosophy and old prejudices: Aspects of the reception of Copernicanism in a divided Europe. Studies in History & Philosophy of Science, 30, 237–262.

Sharratt, M. (1994). Galileo: Decisive innovator. Cambridge University Press.