Two-part question:
1) If you wanted to estimate the number of times since Star Wars that people have referenced the movie by saying "That's no moon!" how would you go about making that calculation?
2) If you wanted to estimate the likelihood that someone has already done the math on that, how would you estimate that?
For part 2, please pretend you don't have direct knowledge of someone actually doing the math. Probability of 1 because demonstrated example case is out of scope.