Galileo Galilei


Scientist and mathematician Galileo Galilei was born on February 15th, 1564, in Pisa, Italy. A pioneer of maths, physics and astronomy, Galileo’s career had long-lasting implications for the study of science.

In 1583, Galileo was first introduced to the Aristotelian view of the universe, which was a religion-based view of how the world worked. A strong Catholic, Galileo supported this view until 1604, when he developed theories on motion, falling objects, and the universal law of acceleration. He began to openly express his support of the controversial Copernican theory, which stated that the Earth and planets revolved around the sun, in direct contrast to the doctrine of Aristotle and the Church.

In July 1609, Galileo learned about a telescope which had been built by Dutch eyeglass makers. Soon he developed a telescope of his own, which he sold to Venetian merchants for spotting ships when at sea. Later that year, Galileo turned his telescope toward the heavens. In 1610 he wrote The Starry Messenger, where he revealed that the moon was not flat and smooth, but a sphere with mountains and craters. He discovered that Venus had phases like the moon, and that Jupiter had revolving moons, which didn’t go around the Earth at all.

With a mounting body of evidence that supported the Copernican theory, Galileo pushed his arguments against church beliefs further in 1613, when he published his observations of sunspots, which refuted the Aristotelian doctrine that the sun was perfect. That same year, Galileo wrote a letter to a student to explain how Copernican theory did not contradict Biblical passages, but that scripture was written from an earthly perspective, and that this implied that science provided a different, more accurate perspective.

In February 1616, a Church inquisition pronounced Galileo as heretical. He was ordered not to “hold, teach, or defend in any manner” the Copernican theory regarding the motion of the Earth. Galileo obeyed the order until 1623, when a friend, Cardinal Maffeo Barberini, was selected as Pope Urban VIII. He allowed Galileo to pursue his work on astronomy on condition it did not advocate Copernican theory.

In 1632, Galileo published the Dialogue Concerning the Two Chief World Systems, a discussion among three people: one supporting Copernicus’ heliocentric theory of the universe, one arguing against it, and one who was impartial. Though Galileo claimed Dialogues was neutral, the Church disagreed. Galileo was summoned to Rome to face another inquisition, which lasted from September 1632 to July 1633. During most of this time, Galileo wasn’t imprisoned, but, in a final attempt to break him, he was threatened with torture, and he finally admitted he had supported Copernican theory. Privately, though, he continued to say he was correct. This ultimately led to his conviction for heresy and as a result he spent his remaining years under house arrest.

Despite the fact he was forbidden to do so, Galileo still went on to write Two New Sciences, a summary of his life’s work on the science of motion and strength of materials. It was another work that has helped cement his place in history as the world’s most pioneering scientist, even if he was not fully appreciated in his own time. Galileo Galilei died on January 8th, 1642.

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Dr Kathryn Bates is a graduate of archaeology and history. She has excavated across the world as an archaeologist, and tutored medieval history at Leicester University. She joined the administrative team at Oxford Open Learning twelve years ago. Alongside her distance learning work, Dr Bates is a bestselling novelist, and an itinerant creative writing tutor for primary school children.

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