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Cox's 1926 study gave Galileo a childhood-records estimate substantially below the adult-corrected figure of 185, reflecting limited documentation of his early life in Pisa and Florence. As with Newton, the methodology rewards subjects whose precocity was recorded by contemporaries.

Galileo improved telescope design (3x magnification on his first instrument, 30x on later ones) and used it to make the observations that established Jupiter's four largest moons, the phases of Venus, and detailed surface features of the moon. His Dialogue Concerning the Two Chief World Systems (1632) defended heliocentrism and led to his Inquisition trial.

His later years were spent under house arrest at Arcetri, where he wrote Two New Sciences (1638), the founding text of modern physics-as-a-quantitative-discipline. The book was smuggled to a Dutch printer for publication because Galileo had been forbidden to publish.