Get the Popular Science daily newsletter💡 What’s the weirdest thing you learned this week? Well, whatever it is, we promise you’ll have an even weirder answer if you listen to PopSci’s hit podcast. The Weirdest Thing I Learned This Week hits Apple, Spotify, YouTube, and everywhere else you listen to podcasts every-other Wednesday morning. It’s your new favorite source for the strangest science-adjacent facts, figures, and Wikipedia spirals the editors of Popular Science can muster. If you like the stories in this post, we guarantee you’ll love the show. FACT: We don’t actually know why period cramps hurt  By Kate Downey  So for context, I get severe period cramps. I have since I was 14. For the last year, I’ve been making the podcast CRAMPED, where I tried to find answers to what I think are very basic questions about my body and my cramps. After all, 90% of menstruating people experience period pain. But it turns out when you try to look into these basic questions and get them answered… there may not be answers out there, largely because of how female bodies are treated in the medical system.  So obviously, if we’re talking about severe period pain, my question was: what’s causing it? And I’ve had this question for 22 years. Like truly what is happening inside my body? I went ahead and did the research, I looked up the medical papers, I found the best information that the internet could give me.  Most folks think they know what’s going on in there—the uterus is squeezing to get the blood out, right? But what’s causing the uterus to squeeze? Why do some people feel mild discomfort while others feel excruciating pain that can cause them to vomit or pass out? Surely science has answers for us…? As it turns out, NOPE! Current studies conducted by the GyRL Lab in Evanston, IL are discovering that, in fact, everything we thought we knew about period cramps might be wrong.  Listen to this week’s episode of Weirdest Thing to hear more about the shockingly recent history of scientific investigation into period pain, and check out CRAMPED for loads more info.  FACT: Rats could make surprisingly decent sommeliers  By Laura Baisas A rat may not be up to the task of selecting a great wine pairing for your dinner anytime soon, but some new research shows that these rodents can learn to differentiate between varieties of vino. The findings are detailed in a study published in the journal Animal Cognition in February.  It’s no secret that rats have great “smellers.” They have about 1,200 genes that function as smell receptors, compared to around 400 for humans. This new research put those receptors to the test. A team from the University of Trento, the University of Lincoln, the University of London and the University of Vienna took nine adult male domesticated rats and trained them to distinguish between sauvignon blanc and riesling. Turns out, they could tell the grape varietals apart fairly well—with one rat named Peanut sticking out. Find out more on this week’s episode.  FACT: People used to use pneumatic tubes to flirt at the club  One of the points I make in the dating and courtship chapter of my book “Been There Done That: A Rousing History of Sex,” is that whatever the hot new technology is, people will probably find a way to use it for dating (and also making porn, but that’s another story).  For instance, in the 80s people would go into little studios and record their bios on VHS tapes that could be sent around to prospective partners.  But what about dating with…pneumatic tubes??? In a 2017 Atlas Obscura article, Michael Waters shared how nightclub patrons in Berlin used pneumatic tubes to send messages to other tables starting in the 1920s. The Resi and the Femina were two clubs said to have spearheaded this trend.  The Resi had live music and space for 1,000 people, plus it apparently had this big water jet show with flashing lights, and it also had both phones and pneumatic tubes, plus paper for writing notes on. Tables had big glowing numbers to designate them, and you could call or send a message to any other table. You could even ask the switchboard to send another patron a gift from a list of available options (via tube, of course).  Listen to this week’s episode of The Weirdest Thing I Learned This Week for more on the thrilling history of pneumatic tube usage, from sending sick cats to the vet to package delivery systems that put our modern food delivery robots to shame. Also: at least one marriage proposal.