One of the beautiful things about The Simpsons, from a certain perspective, is the characters never age. The years pass and they remain essentially as they were when the show premiered in 1989. They’ve changed in some ways, but they don’t grow older. Homer is still the archetypal middle-aged schlub; Bart is still the ultimate troublemaker.

But then you see a tweet like the one posted by The Simpsonslongtime producer and writer Al Jean, that reminds you that The Simpsonshas now been on the air for over 30 years.

Jean points out that if Homer is 39 years old on the show, then he now must have been born in 1980. But when the show began, Bart was supposedly born in ... 1980.