1564-1642

In both his life and through the imprisonment which he was forced to endure in the years leading up to his death, Galileo more than any other figure personified the optimism and struggle of the scientific revolution. He was responsible for a series of discoveries which would change our understanding of the world, while struggling against a society dominated by religious dogma, bent on suppressing his radical ideas.

Galileo Galilei, was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution.

…A Mathematician

Although he was initially encouraged to study medicine, Galileo’s passion was mathematics, and it was his belief in this subject which underpinned all of his work. One of his most significant contributions was not least his application of mathematics to the science of mechanics, forging the modern approach to experimental and mathematical physics. He would take a problem, break it down into a series of simple parts, experiment on those parts, and then analyse the results until he could describe them in a series of mathematical expressions.

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One of the areas in which Galileo had most success with this method was in explaining the rules of motion. In particular, the Italian rejected many of the Aristotelian explanations of physics which had largely endured to his day. One example was Aristotle’s view that heavy objects fall towards earth faster than light ones. Through repeated experiments rolling different weighted balls down a slope (and, legend has it, dropping them from the top of the leaning tower of Pisa!), he found that they actually fell at the same rate. This led to his uniform theory of acceleration for falling bodies, which contended that in a vacuum all objects would accelerate at exactly the same rate towards earth, later proved to be true. Galileo also contradicted Aristotle in another area of motion  by contending that a thrown stone had two forces acting upon it at the same time; one which we now know as ‘momentum’ pushing it horizontally, and another pushing downwards upon it, which we now know as ‘gravity’. Galileo’s work in these areas would prove vital to Isaac Newton’s later discoveries.

…The Pendulum

Galileo’s earliest work involved the study of the pendulum, inspired by observing a lamp swinging in Pisa cathedral. Following further experiments, he concluded that a pendulum would take the same time to swing back and forth regardless of the amplitude of the swing. This would prove vital in the development of the pendulum clock, which Galileo designed and was constructed after his death by his son.

…Through The Telescope

One of the inventions Galileo is often mistakenly credited with today is the invention of the telescope. This is not true; there had been numerous early prototypes that had been mostly developed in Holland before him, and a Dutch optician called Hans Lippershey applied for a patent on his version in 1608. Galileo did, however, develop his own far superior astronomical telescope from just a description of Lippershey’s invention, and quickly employed it to make numerous discoveries. A strong advocate of the Copernican view of planetary motion, Galileo’s initial findings published in the Sidereal Messenger (1610) provided the first real physical evidence to back up this interpretation. As well as discovering craters and mountains in the moon, sunspots and the lunar phases of Venus for the first time, he also noted faint, distant stars which supported the Copernican view of a much larger universe than Ptolemy had ever considered. More importantly, he discovered Jupiter had four moons which rotated around it, directly contradicting the still commonly held view, including that of the Church, that all celestial bodies orbited earth, ‘the centre of the universe.’

…Galileo and Copernicus

Galileo’s Dialogue Concerning the Two Chief World Systems – Ptolemaic and Copernican, in which the Ptolemaic view was ridiculed, attracted the attention of the Catholic Inquisition when it was published in 1632. Threatened with torture, Galileo renounced the Copernican System. His work was placed on the banned ‘Index’ by the Church where it remained until 1835, and he was subject to house arrest for life. But the tide of scientific revolution Galileo had helped instigate proved too powerful to hold back.

After being forced to renounce his heliocentric view of the Earth, Galileo said:

… Nevertheless, it turns!