His theory of relativity transformed theoretical physics andAstronomy during the 20th century. 'GPS', 'GLONASS', and theupcoming 'Galileo' must allow for relativistic effects such as theEarth's gravitational field in order to operate with precision.In 1905, he published a paper with the idea that light energy iscarried in discrete quantized packages to explain experimental datafrom the photoelectric effect, which aided the development ofquantum mechanics.Overall, he published more than 300 scientific papers, plus morethan 150 non-scientific works.