your science briefing for 02.06.2025

The strange, ancient, continent-sized mystery under your feet, the world's oldest sex chromosomes, testing if apes have a theory of mind, and more...

The ground under your feet holds a bizarre secret. Deep inside the Earth’s mantle are two giant, continent sized blobs. One is under the Atlantic, the other under the Pacific, and we don’t really know what they are. Now, new research using echoes from over a hundred earthquakes shows that they’re not just short lived anomalies, but old, stable structures with a very unexpected composition. They might even be evidence of an impact with another planet at the dawn of our solar system… (Nature)

While politicians fight about the fate of TikTok, an expert in disinformation decided to look into whether there is any evidence of pro-Chinese bias on the platform. And his findings seem to match my, admittedly, anecdotal experience of never seeing videos critical of China or its human rights record on The Tok. It seems that the more you use TikTok, the more benign or even positive your view of what China does when it comes to human rights and foreign relations… (PsyPost)

A one hundred meter wide asteroid labeled 2024 YR4 is getting dangerously close to our planet. Unfortunately, it will not be putting us out of our misery in 2032 because a) it’s not nearly large enough for a cataclysmic impact, and b) the odds of an impact are too small, as there’s a more than 99% chance it will miss… (Bad Astronomy)

We’ve all heard about the X and Y chromosomes. In mammals, males can contribute either an X or a Y to determine an offspring’s biological sex. (Generally, if you ignore that all sorts of interesting edge cases exist.) In birds and reptiles, females contribute either a Z or W chromosome to do the same thing. This is why they’re called X/Y and Z/W systems, to pinpoint who has the most input the offspring’s sex. We know Z/W systems evolved first. We just didn’t know when until recently, thanks to octopuses which very likely carry sex chromosomes that evolved 480 million years ago, making them the oldest ones we’ve found so far… (ScienceAlert)

So, there’s a viral “science fact” that apes have never asked us a single question in all the time we’ve taught them sign language because they lack a theory of mind, or the notion that humans do not have the same information they do and will behave in very different ways. There are many problems with this claim, with the biggest one being the implicit assumption that apes and humans process language similarly. But how do we know if apes truly have a theory of mind outside of inference? Well, a recent study applied the same kind of test we give toddlers to test their grasp of theory of mind to a trio of bonobos with very promising results… (Ars Technica)