Sidereus nuncius magna longeque admirabiblia spectacula pandens, suspiciendaque proponens vnicuique praesertim vero philosophis

Galileo Galilei (1564–1642) was an Italian astronomer, mathematician, physicist, philosopher, and inventor. He revolutionized the sciences in the Western world by using mathematics and experimental evidence in the study of natural phenomena. Born in Pisa, Galileo studied in Pisa and Florence and in 1589 was appointed to the chair of mathematics at the University of Pisa. In 1591 he moved to the University of Padua, where he completed much of his most important scientific work. In late 1609, Galileo perfected a telescope of 30x magnification, with which he quickly made a number of startling astronomical discoveries. Galileo’s instrument revealed that the surface of the moon is mountainous, that the Milky Way is composed of separate stars, and that Jupiter is orbited by four satellites, which Galileo called the “Medicean Planets.” Galileo recounted these discoveries in his celebrated work Sidereus nuncius (Starry messenger), published in Venice in March 1610. The work was dedicated to Cosimo de Medici, grand duke of Tuscany, who later that year invited Galileo to come to Florence as court mathematician and philosopher. This appointment freed Galileo from the obligation to teach, but it also removed him from the relative freedom guaranteed by the government of Venice, making him more vulnerable to the proceedings of the Inquisition. Galileo’s support of the theories of Copernicus, which placed the sun rather than the Earth at the center of the universe, was viewed as heretical, and despite being forced to recant, he spent most of his last decade confined to his villa in Tuscany.