Happy Friday! If you're new to Now I Know, you'll notice that today's format differs from the rest of the week. On Fridays, I pause to write the "Weekender," my  "week in review" type of thing, or to share something else I think you may find interesting. Thanks for reading! — Dan

Hi!

Today is May 1st somehow — I swear it was December yesterday — which is also known as “May Day.” And last night, I began to wonder — why do we also have the word “mayday,” which has nothing to do with, well, May or days. So I got to exploring, and … there’s no relationship. Nothing worthy of a regular Now I Know story, for sure, but it’s Friday, and it’s May 1, so here we go.

The May Day holiday has two separate histories — for centuries, in many places, it was a way to celebrate the changing of seasons; spring is here and that’s reason enough to celebrate. It has also become to serve as a labor holiday honoring workers and their contributions, rooted in the events of the Haymarket affair, which became a symbol of the fight for fair working conditions. May Day isn’t a big deal in the United States — few employers give employees today off, and you’ll hardly find a May Day barbecue to go to — but it’s still, kind of, a thing.

The term “mayday” has nothing to do with any of that. It’s a term used to signify that you’re in distress and need help. It dates back to the 1920s, when the aviation industry was just getting off the ground. (Sorry, I couldn’t resist.) The term was coined by Frederick Stanley Mockford, the head of Croydon Airport in England. As Wikipedia editors note, “since much of the air traffic at the time was between Croydon and Le Bourget Airport in Paris, he proposed the term ‘mayday’, the phonetic equivalent of the French m'aider” which translates to “help me.”

The fact that the two terms are spelled and pronounced effectively identically is a coincidence. On the one hand, that’s disappointing — coincidences are everywhere and there’s nothing special about this coincidence other than the historical accident that they share the same name. But on the other hand, it also is a reminder — when you dig deeper and find a story that goes beyond mere coincidence, you’ve probably found something special. This just isn’t it.

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Monday: Orange They Glad He Did The Math: I made a mistake on this one — I said the white-painted tank was from the Apollo 12 mission, which makes no sense because the Space Shuttle wasn’t used for that. It’s from the STS-1 launch, which occurred on April 12, 1981. When I read the caption of the photo on Wikipedia, I saw “April 12” and my brain registered it as “Apollo 12,” which is, obviously, wrong.

Tuesday: The Part of Canada That Doesn't Want You: Gravity falls.

Wednesday: Why You Shouldn’t Take Advice From a Board Game: And especially not Monopoly.

Thursday: Operation Mincemeat: The major was a fraud.

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And thanks! — Dan

Here are a few things you may want to check out over the weekend:

1) “Man vs. Machine” (Toronto Life, 28 minutes, April 2026). The subhead: “For three weeks last spring, ChatGPT convinced Allan Brooks that he had discovered a revolutionary mathematical theory. Now he’s suing OpenAI, claiming its product dragged him down a rabbit hole of lies, caused him to spiral into delusion and destroyed his reputation.” As someone who has spent a lot more than my fair share in Claude Code recently, I can get how this could happen — kind of. LLMs aren’t your friends and you’re (obviously??) not going to make a universe-altering discovery just by having a conversation with one. But they definitely position their responses in ways that make you feel brilliant.

2) “Helium Is Hard to Replace” (Construction Physics, 10 minutes, April 2026). The title sums up the main idea of the story, and I’ve long known that helium is a lot more precious than we treat it. So I’m glad I dug into this one.

3) “Who Killed the Florida Orange?” (Slate, 27 minutes, April 2026). The subhead: “Deep in desiccated Southern groves, the powerhouse of American citrus is suffering a brutal, unrelenting decline. No one wants to face what that means.” I really like clementine oragnes; I hope they’re OK.

Have a great weekend!

Dan