Galileo Galilei, the father of mechanics and part time biomechanic was born 21 years after the death of Copernicus. Galileo spent many years in medical school and often questioned everything his professors taught. He found that the professors could not prove what they taught so he moved onto mathematics where everything had to be proven. Then, at the age of 25, he went to Pisa and taught mathematics. He was a very good lecturer and students would leave their other instructors to hear him speak, so he was forced to resign. He then became a professor at an even more prestigious school in Padua. His spirit and teachings would lead the world once again in the direction of science. Over his years of science, Galileo made a lot of biomechanical aspects known. For example, he discovered that  "animals' masses increase disproportionately to their size, and their bones must consequently also disproportionately increase in girth, adapting to loadbearing rather than mere size. The bending strength of a tubular structure such as a bone is increased relative to its weight by making it hollow and increasing its diameter. Marine animals can be larger than terrestrial animals because the water's buoyancy relieves their tissues of weight."