Twenty years ago I called Carl Sagan to ask him why people believed crazy stuff. Sagan—astronomer, creator of the “golden record” messages to any aliens who might find the Voyager space probes, creator and host of Cosmos, novelist, arguably one of the best-known scientists of the 20th century—would’ve been 83 years old today. Me, I was a fact-checker on the science desk at Newsweek, which meant I mostly did reporting for other people’s stories.