Science Space Deep Space

Plus loud rats and other weird things we learned this week.

Published Nov 5, 2025 9:13 AM EST

“Primordial Clam Chowder” would’ve been tastier.

Get the Popular Science daily newsletter💡

Breakthroughs, discoveries, and DIY tips sent every weekday.

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: “Cosmic latte” could be the aggregate color of our universe—depending on who you ask

*By *Rachel Feltman

In 2002, two astronomers analyzing data from more than 200,000 galaxies decided to answer a question nobody asked: if you could trap all the light in the universe (from the perspective of someone on Earth) in a box and look at it in a dark room, what color would it be? They crunched the numbers and announced the universe was a lovely turquoise. This made perfect sense to them, since the light of young blue stars mixed with an ever-increasing number of older red stars could create a greenish hue.

Right? Wrong. A color science expert named Mark Fairchild caught one glaring error in the fun little thought experiment: the astronomers came up with the color using free software that had been calibrated with the wrong white point. Basically, their results presumed that the viewer was looking at the universe while standing in a room with neon red lighting. When they corrected the issue, the real color turned out to be a slightly pinkish beige—so close to white that they insisted you probably couldn’t even tell the difference.

The researchers then held a public naming contest via email (this was 2002, after all). Submissions included “Big Bang Buff,” “Cosmic Cream,” “Astronomer Green” (someone didn’t get the memo about the correction), and the winning entry: “Cosmic Latte.” Though “Cappuccino Cosmico” actually got more votes, they went with Latte because it means milk in Italian (Galileo’s native tongue) and connects to the Milky Way. When some folks complained that the universe is actually mostly empty space, which reads as black to a human viewer, the researchers basically said that, since the parts of the universe we perceive as black contain zero information, calling the universe black would be boring and pointless.

Listen to learn why “Primordial Clam Chowder” only got four votes (!) and what the actual research project this silly experiment sprang out of taught us about star formation history.

FACT: New York City rats yell louder when ambulances pass by, and AI is helping us eavesdrop on their conversations

*By *Tom Lum

This week’s episode of The Weirdest Thing I Learned This Week features science communicator Tom Lum. He’s sort of been on the show before, thanks to his first viral TikTok back in 2021. Bee jet lag, anyone?

Tom recently made a video for Scientific American about new research on New York City rat communication. He took a deeper dive into that study for this week’s episode.

Brown rats have lived alongside humans for thousands of years, and arrived in NYC when the Big Apple was just getting off the ground. But as ubiquitous as they are in the five boroughs, studying their behavior in these urban wilds has always been tricky. How do you quantitatively analyze animal movements and behavior in one of the noisiest environments on Earth?

Enter computational ecology. Researchers used thermal imaging, ultrasonic microphones, and AI models to parse countless hours of footage and isolate rat squeaks.

They found that NYC rats are… a lot like human New Yorkers, actually. The rodents talk constantly—yapping in groups, yapping alone, and making “human audible vocalizations from aggressive interactions in the park.” Younger rats explore in groups and move slowly like NYU freshmen, while solo rats are much quicker. When an ambulance passed by during one recording, two rats increased their volume to be heard over the siren.

The results suggest that rats have adapted to city life in ways that feel pretty familiar—and remind us that AI can actually be used for awesome academic purposes and not just scammy startups and sloppy propaganda.

You can find more of Tom’s work on his website. And if you’re in the NYC area, you can catch his science game show Our Findings Show at Caveat on November 11! Streaming tickets are also available.

FACT: If you flip part of this single-celled organism backwards, its offspring will be born with the same wonky body plan—and we have no idea why

*By *Lauren Leffer

Imagine cutting off your hands and reattaching them backwards. If you went on to have kids one day, they would be born with their hands in the proper place, right? It turns out that’s not always how inheritance works.

We know this because, in the 1960s, a Baltimore scientist named Tracy Sonneborn decided to Frankenstein some parameciums (single-celled organisms covered in tiny hair-like appendages called cilia). He’d chop off part of a paramecium, rotate it 180 degrees, stick it back on, and watch what happened. Shockingly, the offspring of these collaged cells were born with the same deformities. Despite no changes to DNA whatsoever, flipped cilia stayed flipped for generations. And this isn’t just one guy’s weird experiment. It’s been replicated multiple times.

We still don’t really know why it happens, though there are some vague theories. And it’s not just parameciums, either: more recent studies showed that after being exposed to viruses, worms could inherit immune proteins not coded in their DNA for up to 100 generations.

All of this is kind of awkward for the people who write biology textbooks, because we’ve spent centuries dunking on Jean-Baptiste Lamarck and his theory of inheritance. If you’re not familiar, that’s the idea that, to name one infamous example, giraffes got long necks by stretching for tall leaves and passing the resulting increase in length to their offspring. While that’s not how inheritance actually works, broadly speaking, it does seem like Lamarck might deserve some retroactive credit. Between paramecium experiments and modern epigenetics, we now know of a surprising number of exceptions to our neat Mendelian genetics rules.

2025 Home of the Future Awards

Clever cooking tools, unique appliances, smart home systems, and everything else you’ll want in your home going forward.