Galileo was born in 1564 A.D. at Pisa in Italy. He was the eldest of seven children. His father was a musician and scholar. Galileo himself played the organ and the flute, but it was his contribution to science that made him famous. At first young Galileo had a tutor at home in Pisa. Then he went to school in a monastery at Florence. His father later sent him to the University of Pisa to study medicine but Galileo was more interested in mathematics and physics. He left Pisa without finishing the medical course, but in 1589 A.D. at the age of 25, he became a professor of mathematics.
In 1609 Galileo made small telescope. When he turned his telescope on the sky, he gradually discovered four moons circling the planet Jupiter, craters on the moon, spots on the sun and rings round Saturn. He also observed that the planet Venus has phases like moon. This could only mean that Venus travels round the sun. Galileo became convinced that the Earth and all the other planets orbit the sun.
At that time, the Christian Church thought that any idea that the Earth was not the center of our universe went against the Bible. Church officially banned a book published by the astronomer, Copernicus, in 1543 A.D. setting out such a theory. Galileo’s views on the subject and the books he wrote put him into serious trouble with the church. As the church was very powerful in order to avoid torture and even death. Although he made this declaration, he never changed his real belief. Galileo died in 1642 A.D. at the age of seventy seven.