(4) Galileo vs. (12) Matt Groening
It's tough to imagine science without Galileo's contributions, as evidenced by this terrific reel of nicknames: "The Father of Science," "The Father of Modern Physics," and "The Father of Observational Astronomy." By vastly improving telescopes, Galileo was able to discover the phases of Venus, pick out the largest moons of Jupiter, and help prove that the solar system is heliocentric. His physics research laid the groundwork for the study of motion. On top of that, he survived an inquisition for discounting geocentric theories of the solar system.
(12) Matt Groening
Without creator Matt Groening, there's no The Simpsons. "D'oh!" never even enters your vocabulary. Mr. Burns never makes his millions. Milhouse never becomes a hero to kids whose moms think they're cool. Moe never gives us "Joe Pukepail" as a euphemism for ugliness. You wouldn't remember Troy McClure from anything. Even if you think the show has declined in recent years, pick any episode from the first ten seasons, watch it, and tell us Matt Groening's not a genius.
Galileo gave us improved telescopes, support for heliocentric ideas, fundamental ideas in physics, and discovered all sorts of astronomical truths. Let's not totally dismiss Groening's achievements, though. After all, the man gave us Ralph Wiggum, and you probably quote The Simpsons much more frequently than you look through a telescope. Groening also created the brilliant comic strip Life in Hell and the cult favorite show Futurama. One's a scientist for the ages; the other's a rare comedic talent. Which one's the bigger genius?
[See the whole bracket here.]