GALILEO Galileo (1564- 1642) was an Italian astronomer and physicist whose discoveries in mechanics and astronomy contribute greatly to the progression of Science. He started his Science career at the University of Pisa where he studied to be a physician. Galileo made his first important discovery while still studying in Pisa when he was only 19, it was when he was in the cathedral observing the swinging action of the hanging lamps, he wondered if the duration of their swings was always the same regardless of the distance they traveled. He used his pulse as a time keeper and found out he was right, so he set off back home to experiment.

In Galileo s third year at Pisa he began to study mathematics and he was so fascinated by it that he stopped studying medicine and decided to return to Florence. After only five years of studying math and physics in Florence he was nominated as professor of mathematics at the University of Pisa. Then, after only three years of teaching at Pisa he became professor of mathematics at Padua. Galileo spent 18 years of his life here. He met his wife Marina Gamba here and had three children. His lectures were an enormous success, and in his house he had a workshop in which he constructed mathematical instruments with the help of a mechanic.

He invented a device called the "geometrical and military compass", and also, an air thermometer. The telescope had been invented in Holland about 1608, and the following year Galileo made himself a small instrument with a lead tube. In August 1609 he showed it to the Doge of Venice and other powerful people from the top of the St. Mark s Cathedral. The enthusiasm shown by the Doge was enormous, and Galileo received an additional salary. In 1610 Galileo used a larger telescope and studied the Moon with it, he saw that the moon was not smooth as everyone thought it was but, covered with mountains and valleys and craters.

He then discovered that Venu has different phases like the Moon, and showed us that it revolves around the Sun. With this theory he proved that the Earth was not the centre of the universe. The importance of these discoveries added enormously to Galileo s fame, and Cosimo II called him to Florence to appoint him first philosopher and mathematician to be the Grand Duke of Tuscany. His discoveries which were published in 1610 in his book called Side reus Nuncios (The Sidereal Messenger), received recognition from the greatest scientists around the world.

On one of his journeys to Rome, around 1611, Galileo received honour by Pope Paul V. In the garden of the Quirinal he was able to demonstrate his discoveries to the Jesuits of the College of Rome and was enlisted in the Linnean academy. His astronomical discoveries were based on the Copernican system, and in four letters he tried to show that the theory of the Earth s movement around the Sun was not in opposition to the Bible. Copies of these letters were circulated and provoked violent attacks against him, so that he was finally denounced to the Inquisition. On Galileo s next visit to Rome, the Holy Office announced a censure against the Copernican system in 1616, and stopped Galileo from teaching, defending, or even discussing it.

Afraid of imprisonment, Galileo agreed. The last years of his life were spent at Arce tri where he lost his eyesight. He could not observe celestial bodies anymore but he continued to teach about them.