Description
Born: 1564
Died: 1642


Galileo was an Italian astronomer, mathematician and physicist whose discoveries in the 16th and 17th centuries helped to revolutionise many areas of science. Galileo was the first person to express the movements of objects in terms of mathematical formulas and helped to advance the practise of science by his use of experimentation to investigate scientific theory. One of his most famous experiments took place in Pisa cathedral where he is commonly believed to have timed a swinging lamp by his own heartbeat to discover that each swing of a pendulum takes the same amount of time independent of the size of the arc.

Galileo published research which contradicted the previously long accepted theories of Aristotle, using experimentation to show that the path of a projectile object is parabolic and that velocity is proportional to time and independent of weight and density. According to popular belief, this last theory was proved by famously dropping two objects off of the Leaning Tower of Pisa, this experiment however, was actually carried out by Simon Stevin, and not Galileo.

In 1609 Galileo built the first complete astronomical telescope after the design of a simple magnifying instrument by Sacharias Jansen from 1608. He used this to discover four of the moons of Jupiter and that the surface of Earth’s moon was mountainous. His observations of the movements of Venus and Saturn led Galileo to conclude that the solarcentric theories of people like Copernicus and Giodano Brunos were true. In 1613 he expressed his support for the theory that the Sun was the centre of the solar system in a work on sunspots. It was not until 1632, when he published ‘Dialogue on the two chief systems of the World’, that Galileo came in direct conflict with the church. The Copernican theory had been denounced by the Pope as harmful to the faith in 1616 and Galileo had been expressly warned not to favour the theory. His disregard for the warning led to his trial by the inquisition in 1633 where he was forced to retract his support. Galileo was placed under house arrest in Sienna but was later allowed to live in isolation in Arcetri where he continued his scientific work until his death in 1642.