Galileo Galilei was born on the 15th of February, 1564 in Pisa, Italy. He died on the 8th of January 1642 in Arcetri, Italy.

Galileo became a mathematician, physicist,engineer and astronomer. He observed that the moon had mountains just like earth. He also discovered, using his telescope, that Jupiter has 4 moons. He also observed that the sun has sunspots which appear to be dark in colour. Galileo came to believed that the idea that sun and other planets orbited around the earth was not correct. He felt that astronomer Copernicus had a better idea, that the sun was the centre of the universe.

Nowadays we view Galileo as the 'father of observational astronomy or the father of modern physics'.