Galileo

Galileo was born in Pisa, in the Tuscany region of Italy, on February 15, 1564, the son of Vincenzo Galilei. Galileo was their first child out of seven (some people believe six). Most authorities say he was the most talented of the children.

Galileo was tutored from a very young age. Later, he attended the University of Pisa but was forced to halt his studies there for financial reasons. However, he was offered a position on its faculty in 1589 and taught mathematics. Soon after, he moved to the University of Padua and served on its faculty, teaching geometry, mechanics, and astronomy until 1610. During this period he concentrated on science, and made many significant discoveries.

Although he was a devout Roman Catholic, Galileo fathered three children out of wedlock with Marina Gamba. They had two daughters (Virginia and Livia) and one son (Vincenzio). Because of their illegitimate birth, both girls were sent to the convent of San Matteo in Arcetri at early ages and remained there for the rest of their lives. Virginia took the name Maria Celeste upon entering the convent. She was Galileo's eldest child, the most beloved, and inherited her father's sharp mind. She died on April 2, 1634, and is currently buried with Galileo at the Basilica di Santa Croce di Firenze. Livia (b. 1601) took the name Suor Arcangela, made no great impact on the world, and was ill for most of her life. Vincenzio (b. 1606) was later legitimized and married Sestilia Bocchineri.

In 1612, Galileo went to Rome, where he joined the Accademia dei Lincei and observed sunspots. In 1612, opposition arose to the Copernican theories, which Galileo supported. In 1614, from the pulpit of Santa Maria Novella, Father Tommaso Caccini (1574-1648) denounced Galileo's opinions on the motion of the Earth, judging them dangerous and close to heresy. Galileo went to Rome to defend himself against these accusations, but, in 1616, Cardinal Roberto Bellarmino personally handed Galileo an admonition enjoining him to neither advocate nor teach Copernican astronomy as religious doctrine. In 1622, Galileo wrote the The Assayer (Saggiatore), which was approved and published in 1623. In 1624, he developed the first known example of the microscope. In 1630, he returned to Rome to apply for a license to print the Dialogue Concerning the Two Chief World Systems, published in Florence in 1632. In October of that year, however, he was ordered to appear before the Holy Office in Rome. The court issued a sentence of condemnation and forced Galileo to abjure. As a result, he was confined in Siena and eventually, in December 1633, he was allowed to retire to his villa in Arcetri. In 1634, he was deprived of the support of his beloved daughter, Sister Maria Celeste (1600-1634), who died prematurely. In 1638, almost totally blind, Galileo published his final book, Two New Sciences, in Leiden. He died in Arcetri on the January 8, 1642, in the company of his student Vincenzo Viviani.

[edit] Scientific methods

In the pantheon of the scientific revolution, Galileo Galilei takes a high position because of his pioneering use of quantitative experiments with results analyzed mathematically. There was no tradition of such methods in European thought at that time; the great experimentalist who immediately preceded Galileo, William Gilbert, did not use a quantitative approach. However, Galileo's father, Vincenzo Galilei, a lutenist and music theorist, had performed experiments in which he discovered what may be the oldest known non-linear relation in physics, between the tension and the pitch of a stretched string. These observations were in the Pythagorean tradition of music, well-known to instrument makers, that whole-number mathematical relationships define harmonious (pleasing) scales. Thus, a limited form of mathematics had long made its way into physical science at the point of music, and young Galileo was in a position to see his own father's observations generalize that relationship still further. Galileo himself would find credit as the first to plainly state that the laws of nature are mathematical, and (as he said) the idea that "the language of God is mathematics." This was a sharp break with earlier traditions of science: up until this point, following Aristotle, logic, not mathematics had been seen to be the basic intellectual tool of science.

Galileo also contributed to the rejection of blind allegiance to authority (like the Church) or other thinkers (such as Aristotle) in matters of science and to the separation of science from philosophy or religion. These are the primary justifications for his description as the "father of science".

In the 20th century some authorities, in particular the distinguished French historian of science Alexandre KoyrÐ"©, challenged the validity of Galileo's experiments. The experiments reported in Two New Sciences to determine the law of acceleration of falling bodies, for instance, required accurate measurements of time, which appeared to be impossible with the technology of the 1600s. According to KoyrÐ"©, the law was arrived at deductively, and the experiments were merely illustrative thought experiments.

Later research, however, has validated the experiments. The experiments on falling bodies (actually rolling balls) were replicated using the methods described by Galileo (Settle, 1961), and the precision of the results were consistent with Galileo's report. Later research into Galileo's unpublished working papers from as early as 1604 clearly showed the validity of the experiments and even indicated the particular results that led to the time-squared law (Drake, 1973).

He had even attempted to measure the speed of light. He did it in an ingenious way.

He climbed up a hill and told someone else to climb up another hill. They both had lanterns with shutters.

He then opened the shutter of his lantern and counted to see how long it took for the other person to open theirs.

Using mathematics, he tried to work out how fast the light was travelling.

But when he tried to repeat the experiment with hills further apart, he still got the same time lapse. This was because he was measuring the reaction time of the person.

Galileo showed a remarkably modern appreciation for the proper relationship between mathematics, theoretical physics, and experimental physics. For example:

He understood the mathematical parabola, both in terms of conic sections and in terms of the square-law.

He asserted that the parabola was the theoretically-ideal