 Galileo Galilei ( Italian pronunciation : [ ɡaliˈlɛːo ɡaliˈlɛi ] ; 15 February 1564 – 8 January 1642 ) was an Italian astronomer , physicist , engineer , philosopher , and mathematician who played a major role in the scientific revolution of the seventeenth century . He has been called the " father of observational astronomy " , the " father of modern physics " , and the " father of science " . His contributions to observational astronomy include the telescopic confirmation of the phases of Venus , the discovery of the four largest satellites of Jupiter ( named the Galilean moons in his honour ) , and the observation and analysis of sunspots . Galileo also worked in applied science and technology , inventing an improved military compass and other instruments . 
