From his childhood in 16th-century Italy, Galileo Galilei had a thirst for science and knowledge. But no one would have thought this studious little boy would grow up to make discoveries that changed the way we view the universe itself. For Galileo discovered that the Earth was not the center of the universe as everybody thought, but that the Earth moved around the Sun. Because of this world-changing belief, Galileo faced the threat of imprisonment and even death.