Why Carl Sagan is Truly Irreplaceable

The adult Sagan always sounded like the smartest person in the room, but in the papers we encounter this interesting note in a 1981 file, right after “Cosmos” hit it big: “I think I’m able to explain things because understanding wasn’t entirely easy for me. Some things that the most brilliant students were able to see instantly I had to work to understand. I can remember what I had to do to figure it out. The very brilliant ones figure it out so fast they never see the mechanics of understanding.”