Peanuts by Charles Schulz for August 14, 1958
Transcript:
Linus is looking up in the sky. He asks Lucy as she walks by, "Lucy, why is the sky blue?"(BR) (BR) He jumps as she snaps, "Because It Isn't Green!!"(BR) (BR)He watches as she walks away.(BR) (BR) He resumes looking up in the sky and says, "That just shows how stupid I am..I thought there would be a more complicated reason..."(BR) (BR)
That means she doesn’t know.