Isaac Newton

Sir Isaac Newton was an English physicist and mathematician. One of his most famous accomplishments was formulating the theory of gravity. The Fourth Doctor once claimed that he sat in Newton's tree dropping apples onto his head, then explained gravity to him over dinner. (TV: The Pirate Planet) It later came to light that Newton remained upset about that event, as his nose bled for three days afterward. (AUDIO: Summer)

At some point the Doctor took Newton on a trip to planet Practas Seven, but according to the Tenth Doctor, Newton didn't take the experience very well and "sat in a corner and whimpered". (COMIC: Final Sacrifice)