Galileo Galilei, Italian mathematician, astronomer, and physicist, made several significant contributions to modern scientific thought. As the first man to use the telescope to study the skies, he amassed evidence that proved the Earth revolves around the Sun and is not the centre of the universe, as had been believed. His position represented such a radical departure from accepted thought that he was tried by the Inquisition in Rome, ordered to recant, and forced to spend the last eight years of his life under house arrest. He informally stated the principles later embodied in Newton's first two laws of motion. Because of his pioneer work in gravitation and motion and in combining mathematical analysis with experimentation, Galileo often is referred to as the founder of modern mechanics and experimental physics.

Perhaps the most far-reaching of his achievements was his reestablishment of mathematical rationalism against Aristotle's logico-verbal approach and his insistence that the "Book of Nature is . . . written in mathematical characters." From this base, he was able to found the modern experimental method. Galileo was born at Pisa on February 15, 1564, the son of Vincenzo Galilei, a musician. He received his early education at the monastery of Vallombrosa near Florence, where his family had moved in 1574. In 1581 he entered the University of Pisa to study medicine. While in the Pisa cathedral during his first year at the university, Galileo supposedly observed a lamp swinging and found that the lamp always required the same amount of time to complete an oscillation, no matter how large the range of the swing. Later in life Galileo verified this observation experimentally and suggested that the principle of the pendulum might be applied to the regulation of clocks.

Until he supposedly observed the swinging lamp in the cathedral, Galileo had received no instruction in mathematics. Then a geometry lesson he overheard by chance awakened his interest, and he began to study mathematics and science with Ostilio Ricci, a teacher in the Tuscan court. But in 1585, before he had received a degree, he was withdrawn from the university because of lack of funds. Returning to Florence, he lectured at the Florentine academy and in 1586 published an essay describing the hydrostatic balance, the invention of which made his name known throughout Italy. In 1589 a treatise on the centre of gravity in solids won for Galileo the honourable, but not lucrative, post of mathematics lecturer at the University of Pisa.

Galileo then began his research into the theory of motion, first disproving the Aristotelian contention that bodies of different weights fall at different speeds. Because of financial difficulties, Galileo, in 1592, applied for and was awarded the chair of mathematics at Padua, where he was to remain for 18 years and perform the bulk of his most outstanding work. At Padua he continued his research on motion and proved theoretically (about 1604) that falling bodies obey what came to be known as the law of uniformly accelerated motion (in such motion a body speeds up or slows down uniformly with time). Galileo also gave the law of parabolic fall (e.g., a ball thrown into the air follows a parabolic path). The legend that he dropped weights from the leaning tower of Pisa apparently has no basis in fact.

Design and Graphics Copyright © 1996-2003, DeftCOM Systems Limited.
All Rights Reserved.