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Neanderthals were running a potentially lifesaving “fat factory” around 125,000 years ago in what is now Germany, a new study finds.

The research, published Wednesday (July 2) in the journal Science, reveals that these archaic human relatives had a process for extracting grease from animal bones — and it may have saved them from a lethal condition.

Astronomers using ESO’s Very Large Telescope (VLT) have imaged SNR 0509-67.5, a very young (300-350 years old) remnant of Type Ia supernova, and spotted patterns that confirm its star suffered a pair of explosive blasts.

“White dwarfs — the small, inactive cores left over after stars like our Sun burn out their nuclear fuel — can produce what astronomers call a Type Ia supernova,” said Priyam Das, a Ph.D. student at the University of New South Wales Canberra.

“Much of our knowledge of how the Universe expands rests on these supernovae, and they are also the primary source of iron on our planet, including the iron in our blood.”

“Yet, despite their importance, the long-standing puzzle of the exact mechanism triggering their explosion remains unsolved.”

All models that explain Type Ia supernovae begin with a white dwarf in a pair of stars.

If it orbits close enough to the other star in this pair, the dwarf can steal material from its partner.

In the most established theory behind Type Ia supernovae, the white dwarf accumulates matter from its companion until it reaches a critical mass, at which point it undergoes a single explosion.

However, recent studies have hinted that at least some Type Ia supernovae could be better explained by a double explosion triggered before the star reached this critical mass.

The new VLT image of SNR 0509-67.5 proves their hunch was right: at least some Type Ia supernovae explode through a ‘double-detonation’ mechanism instead.

In this alternative model, the white dwarf forms a blanket of stolen helium around itself, which can become unstable and ignite.

This first explosion generates a shockwave that travels around the white dwarf and inwards, triggering a second detonation in the core of the star — ultimately creating the supernova.

Until now, there had been no clear, visual evidence of a white dwarf undergoing a double detonation.

Recently, astronomers have predicted that this process would create a distinctive pattern or fingerprint in the supernova’s still-glowing remains, visible long after the initial explosion.

Research suggests that remnants of such a supernova would contain two separate shells of calcium.

Das and colleagues found this fingerprint in a supernova’s remains.

“The results show a clear indication that white dwarfs can explode well before they reach the famous Chandrasekhar mass limit, and that the ‘double-detonation’ mechanism does indeed occur in nature,” said Dr. Ivo Seitenzahl, an astronomer at Heidelberg Institute for Theoretical Studies.

The astronomers were able to detect these calcium layers in SNR 0509-67.5 by observing it with the Multi Unit Spectroscopic Explorer (MUSE) on VLT.

This provides strong evidence that a Type Ia supernova can occur before its parent white dwarf reaches a critical mass.

“This tangible evidence of a double-detonation not only contributes towards solving a long-standing mystery, but also offers a visual spectacle,” Das said.

“Revealing the inner workings of such a spectacular cosmic explosion is incredibly rewarding.”

The team’s results appear today in the journal Nature Astronomy.

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P. Das et al. Calcium in a supernova remnant as a fingerprint of a sub-Chandrasekhar-mass explosion. Nat Astron, published online July 2, 2025; doi: 10.1038/s41550-025-02589-5

It’s not easy to look at a sea spider and see an animal so representative of its kind that it may help scientists sort out the evolution of almost everything with eight legs. But that’s the potential a new study finds in these spindly, strikingly strange bottom-dwellers.

After all, once you’re done counting the legs, you quickly run out of resemblances between the 1,300-some known species of sea spider and their relatives like actual spiders, scorpions, ticks, mites and horseshoe crabs.

Sea spiders breathe through their skin, moving oxygen around their body using a kind of peristalsis (muscle contractions similar to how you squeeze food down your throat). When it’s time to make babies, the males cement the fertilized eggs onto themselves and carry them around on their bodies until they hatch. There isn’t even much body to speak of, because sea spiders look like plumbing schematics. They’re all tubes, mostly because they have no abdomen — that back end that bears the scorpion’s stinger, that stores all that blood in a well-fed tick, and that gives tarantulas their bulbous, hairy mass.

“They’re weird,” says Prashant Sharma, a researcher who specializes in that sort of thing. His University of Wisconsin–Madison lab is intermittently stocked with blind arachnids that live only in a handful of Eastern Mediterranean caves, scorpion-shaped vinegaroons that spray acid from their butts, and daddy longlegs that have … short legs.

“Sea spiders are just incredibly cool and understudied animals. So, that’s what draws us to them,” Sharma adds.

That interest has revealed a more scientific reason to be drawn to sea spiders. They are a useful anchor for the genetics of the chelicerates, a group that includes all of the charismatic and consequential, many-legged animals mentioned above.

Sharma, a UW–Madison professor of integrative biology, studies the evolution of chelicerates, digging deep into their genes to understand better how their varied, intricate bodies have developed. He’s studied how and when they picked up tricks like venom and shown that the horseshoe crab belongs to this cohort just as much as the house spider.

What many of his animal subjects have had in common over the years is a twist in their evolution that strikes geneticists as a bit of an advantage: free DNA real estate. Somewhere along their line, they went through a process called whole-genome duplication.

“There are a few mechanisms for whole-genome duplication,” Sharma says, including a misstep in cell division or combining genomes with a close relative. “But the result is a species getting an extra copy of all of its chromosomes. You can look at all those extra genes as more places where new traits, new functions could develop.”

Sharma and collaborators — including former lab members Siddharth Kulkarni and Emily Setton, and scientists at the Arctic University of Norway — published the first high-quality genome of a sea spider species today in the journal BMC Biology. The work was spearheaded by their colleagues at the University of Vienna, most notably Georg Brenneis, one of the very few people on the planet working on sea spider development.

The study centers on the knotty sea spider, Pycnogonum litorale, which is widespread on rocky sea beds across the North Atlantic Ocean and looks a lot like a tiny, tangled ginger root. The researchers found that this specific sea spider has never experienced whole-genome duplication.

Because whole genomes, once duplicated, tend to keep traces of that doubling of genes, this places P. litorale somewhere near the base of the entire chelicerate family tree relative to all those branches that include species with duplicated genomes. It’s a steady point to which scientists can trace back the progression of variation across modern spiders and related species.

“They are an important reference for the evolution of all these species, which include some of the most significant agricultural pests, like mites, and vectors for human disease, like ticks,” says Sharma, whose work is supported by the National Science Foundation.

The researchers also may have uncovered the reason sea spiders have no abdomen. They are missing a gene, handily called “Abdominal-A,” from a group of genes called the Hox cluster known for its importance to organizing body parts. As a result, sea spiders have stuffed all the usual contents of an abdomen — stomachs, reproductive organs, the stuff they use to breathe — into their legs.

Weirder still, there are fossil sea spiders from tens and hundreds of millions of years ago that do sport an abdomen.

“We don’t know quite when that structure was lost. We know they started out looking more like modern arthropods,” says Sharma, referring to the wider group of animals with exoskeletons and segmented bodies, including beetles and crustaceans and bees and his chelicerates. “And then, at some point, they just went totally bizarre. So weird.”

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This research was supported in part by a grant from the National Science Foundation (IOS-2016141).

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