The people who changed our view of the world

Three biographical sketches

Copernicus was born in 1473 and went to university at Cracow before becoming a canon in a cathedral in Germany. One of his passions was astronomy and using his careful unaided observations of the night sky, he developed the idea that the Sun was at the centre of the universe (pre-dating the work of Galileo). However, he was reluctant to publish his work fearing the opposition of the Church. Copernicus' De Revolutionibus Orbium Coelestium, published a few days after his death, gave new currency to the ancient Pythagorean hypothesis that the Sun was at the centre of the universe and that the planets (including the Earth) orbited the Sun. The work was, however, published with a preface by Andreas Osiander, that declared that the theory of the Polish astronomer was a mere hypothesis whose value lay in the way that it simplified astronomical calculations.

Giordano Bruno went well beyond Copernicus (and the available evidence), suggesting that space was boundless and that the Sun and its planets were but one of any number of similar systems; why, there may be other inhabited worlds with rational beings equal or possibly superior to ourselves. For such blasphemy, Bruno was tried before the Inquisition, condemned and burned at the stake in 1600. There is a statue of him now in the Campo Del Fiore (the main square of Rome).

Galileo Galilei was born in Pisa in 1564, the son of Vincenzo Galilei, well known for his studies of music, and Giulia Ammannati. He was exceptionally clever from a young age, gaining a chair in mathematics at the University of Pisa at the age of 27. He was then appointed to the chair of mathematics at Padua where he remained until 1610. He built a telescope with which he made celestial observations, the most spectacular of which was his discovery of the satellites of Jupiter. In 1610 he was nominated the foremost mathematician of the University of Pisa and given the title of Mathematician to the Grand Duke of Tuscany. He studied Saturn and observed that Venus has phases like the Moon. The only explanation for these had to be that Venus was orbiting the Sun. In 1611 he became a member of the Accademia dei Lincei, and observed sunspots for the first time. In 1612 he began to encounter serious opposition to his theory of the motion of the Earth that he taught after Copernicus.

In 1614, Father Tommaso Caccini denounced the opinions of Galileo on the motion of the Earth from the pulpit of Santa Maria Novella, judging them to be incorrect. Galileo therefore went to Rome where he defended himself against these charges, but in 1616 he was admonished by Cardinal Bellarmino and told that he must not uphold Copernican astronomy because it went against the doctrine of the Church. In 1622 he wrote the Saggiatore (The Assayer) which was approved and published in 1623. In 1630 he returned to Rome from Florence to obtain the right to publish his dialogue on the two chief world systems, which was eventually published in Florence in 1632.

In October of 1632 he was summoned by the Holy Office to Rome. The tribunal passed a sentence condemning him and compelled Galileo to solemnly denounce his theory. He was sent to exile in Siena and finally, in December of 1633, he was allowed to retire to his villa in Arcetri. His health condition was steadily declining. By 1638 he was completely blind, and also by now bereft of the support of his daughter, Sister Maria Celeste, who died in 1634. Galileo died in Arcetri on 8 January 1642.