Earth’s inner corecore (I'm sorry)

What's inside Earth? A solid ball of metal, apparently.

As it turns out, Earth’s heart is most likely an infernally hot lump of solid metal. Sounds kinda like my own lately ;) 

Scientists have long suspected there may be a ball of metal buried at the center of Earth, within its inner core, but new findings based on the behavior of seismic waves seem to finally confirm it. Seismologists from The Australian National University analyzed data from roughly 200 earthquakes of magnitude 6 or higher that occurred in the last decade, measuring the differing speeds of seismic waves as they bounced back and forth through Earth like ping pong balls.

The waves’ activity suggested the presence of a 400-mile-thick (approx. 650 km) central ball of iron, supporting an earlier hypothesis about a possible “innermost inner core.” A pretty uninspired name, honestly, but that’s beside the point. It can now be thought that Earth’s structure contains five layers: the crust, the mantle, the outer core, the inner core, and the innermost inner core.

“This inner core is like a time capsule of Earth's evolutionary history — it’s a fossilized record that serves as a gateway into the events of our planet’s past,” said Professor Hrvoje Tkalčić, from the ANU Research School of Earth Science. “Events that happened on Earth hundreds of millions to billions of years ago.” This ultimate core, the core of all cores, he says, “could hold the secrets to piecing together the mystery of our planet’s formation.”

The research was published this week in Nature Communications. 

Credit: Drew Whitehouse, Son Phạm, and Hrvoje Tkalčic.

This next one’s a little gross…

Nature can be pretty horrifying sometimes, and a just-published video captured in southern England last summer shows exactly one such occasion. 

A noble false widow spider (Steatoda nobilis) was recorded feasting on a pygmy shrew (Sorex minutus), marking a first — at least, that we’ve observed — for any species of false widow. It happened right outside a bedroom window, documented by Chichester resident Dawn Sturgess who will presumably never sleep again. And, not to be dramatic, the footage is harrowing. I’ll drop a snippet below.

Here’s how it went down, per the paper published in Ecosphere:

In Chichester, West Sussex, southern England, on the morning of Thursday 4th August 2022, one of the authors (DS) found a small mammal entangled in a spider web constructed on the outside of a first-floor bedroom window, adjacent to a large bushy wisteria (Wisteria sp.) partially covering the exterior wall. The mammal was still alive, but only an initial few slight movements were observed. The spider was moving back and forth between the mammal and the rafter, and the mammal was hoisted upwards, approximately 25 cm. After approximately 20 min, the mammal had been lifted into the rafters, slightly out of view. The spider later wrapped the mammal in silk. Three days later, the spider released the mammal, which was found on the window ledge.

Credit: Dawn Sturgess

The pygmy shrew may be tiny to us, but it’s at least three times the size of that spider (just eyeballing it). That’s clearly no problem for the latter. Noble false widow spiders are equipped with a neurotoxic venom that can immobilize small vertebrates like this unfortunate creature, and overall they’re just “perfectly adapted to take down large prey,” said Dr. Michel Dugon, from the University of Galway, “combining potent venom, extremely strong silk, and complex hunting behavior.” 

The noble false widow is invasive globally, originating from Madeira and the Canary Islands. And it’s apparently broadening its diet. 

Before I go, PS recommends:

We Sold Our Souls (2018), Grady Hendrix. (Because there’s a hole at the center of the world, and inside that hole is Black Iron Mountain)

‘Til next time!