Enlarge (credit: Derek Berwin)

Our planet is choking on plastics. Some of the worst offenders, which can take decades to degrade in landfills, are polypropylene—which is used for things such as food packaging and bumpers—and polyethylene, found in plastic bags, bottles, toys, and even mulch.

Polypropylene and polyethylene can be recycled, but the process can be difficult and often produces large quantities of the greenhouse gas methane. They are both polyolefins, which are the products of polymerizing ethylene and propylene, raw materials that are mainly derived from fossil fuels. The bonds of polyolefins are also notoriously hard to break.

Now, researchers at the University of California, Berkeley have come up with a method of recycling these polymers that uses catalysts that easily break their bonds, converting them into propylene and isobutylene, which are gasses at room temperature. Those gasses can then be recycled into new plastics.

Enlarge (credit: Hal Beral)

For many creatures, having a limb caught in a predator’s mouth is usually a death sentence. Not starfish, though—they can detach the limb and leave the predator something to chew on while they crawl away. But how can they pull this off?

Starfish and some other animals (including lizards and salamanders) are capable of autonomy (shedding a limb when attacked). The biology behind this phenomenon in starfish was largely unknown until now. An international team of researchers led by Maurice Elphick, professor of Animal Physiology and Neuroscience at Queen Mary University of London, have found that a neurohormone released by starfish is largely responsible for detaching limbs that end up in a predator’s jaws.

So how does this neurohormone (specifically a neuropeptide) let the starfish get away? When a starfish is under stress from a predatory attack, this hormone is secreted, stimulating a muscle at the base of the animal’s arm that allows the arm to break off.

Enlarge / Artist's conception of the state of the Earth during its global glaciations. (credit: NASA)

Earth has gone through many geologic phases, but it did have one striking period of stasis: Our planet experienced a tropical environment where algae and single-celled organisms flourished for almost 2 billion years. Then things changed drastically as the planet was plunged into a deep freeze.

It was previously unclear when Earth became a gargantuan freezer. Now, University College London researchers have found evidence in an outcrop of rocks in Scotland, known as the Port Askaig Formation, that show evidence of the transition from a tropical Earth to a frozen one 717 million years ago. This marks the onset of the Sturtian glaciation and would be the first of two "snowball Earth" events during which much of the planet’s surface was covered in ice. It is thought that multicellular life began to emerge after Earth thawed.

Found in the Scottish islands known as the Garvellachs, this outcrop within the Port Askaig Formation is unique because it offers the first conclusive evidence of when a tropical Earth froze over—underlying layers that are a timeline from a warmer era to a frigid one. Other rocks that formed during the same time period in other parts of the world lack this transitional evidence because ancient glaciers most likely scraped it off.

Enlarge / Artist's rendition of the LADEE mission above the lunar surface. (credit: NASA/ Dana Berry)

The Moon may not have much of an atmosphere, mostly because of its weak gravitational field (whether it had a substantial atmosphere billions of years ago is debatable). But it is thought to presently be maintaining its tenuous atmosphere—also known as an exosphere—because of meteorite impacts.

Space rocks have been bombarding the Moon for its 4.5-billion-year existence. Researchers from MIT and the University of Chicago have now found that lunar soil samples collected by astronauts during the Apollo era show evidence that meteorites, from hulking meteors to micrometeoroids no bigger than specks of dust, have launched a steady flow of atoms into the exosphere.

Though some of these atoms escape into space and others fall back to the surface, those that do remain above the Moon create a thin atmosphere that keeps being replenished as more meteorites crash into the surface.

Enlarge / The fossil in question, oriented with its head to the left. (credit: Yang Jie / Zhang Xiguang)

Around half a billion years ago, in what is now the Yunnan Province of China, a tiny larva was trapped in mud. Hundreds of millions of years later, after the mud had long since become the black shales of the Yuan’shan formation, the larva surfaced again, a meticulously preserved time capsule that would unearth more about the evolution of arthropods.

Youti yuanshi is barely visible to the naked eye. Roughly the size of a poppy seed, it is preserved so well that its exoskeleton is almost completely intact, and even the outlines of what were once its internal organs can be seen through the lens of a microscope. Durham University researchers who examined it were able to see features of both ancient and modern arthropods. Some of these features told them how the simpler, more wormlike ancestors of living arthropods evolved into more complex organisms.

The research team also found that Y. yuanshi, which existed during the Cambrian Explosion (when most of the main animal groups started to appear on the fossil record), has certain features in common with extant arthropods, such as crabs, velvet worms, and tardigrades. “The deep evolutionary position of Youti yuanshi… illuminat[es] the internal anatomical changes that propelled the rise and diversification of [arthropods],” they said in a study recently published in Nature.

Enlarge (credit: Peter Muller)

Singing off-key in front of others is one way to get embarrassed. Regardless of how you get there, why does embarrassment almost inevitably come with burning cheeks that turn an obvious shade of red (which is possibly even more embarrassing)?

Blushing starts not in the face but in the brain, though exactly where has been debated. Previous thinking often reasoned that the blush reaction was associated with higher socio-cognitive processes, such as thinking of how one is perceived by others.

After studying subjects who watched videos of themselves singing karaoke, however, researchers led by Milica Nicolic of the University of Amsterdam have found that blushing is really the result of specific emotions being aroused.

Enlarge / Renditions of a possible composition of LHS 1140 b, with a patch of ocean on the side facing its host star. Earth is included at right for scale. (credit: BENOIT GOUGEON, UNIVERSITÉ DE MONTRÉAL)

Of all the potential super-Earths—terrestrial exoplanets more massive than Earth—out there, an exoplanet orbiting a star only 40 light-years away from us in the constellation Cetus might be the most similar to have been found so far.

Exoplanet LHS 1140 b was assumed to be a mini-Neptune when it was first discovered by NASA’s James Webb Space Telescope toward the end of 2023. After analyzing data from those observations, a team of researchers, led by astronomer Charles Cadieux, of Université de Montréal, suggest that LHS 1140 b is more likely to be a super-Earth.

If this planet is an alternate version of our own, its relative proximity to its cool red dwarf star means it would most likely be a gargantuan snowball or a mostly frozen body with a substellar (region closest to its star) ocean that makes it look like a cosmic eyeball. It is now thought to be the exoplanet with the best chance for liquid water on its surface, and so might even be habitable.

Enlarge / One of the craters identified seismically, then confirmed through orbital images. (credit: NASA/JPL-Caltech/University of Arizona)

Mars trembles with marsquakes, but not all of them are driven by phenomena that occur beneath the surface—many are the aftermath of meteorite strikes.

Meteorites crash down to Mars every day. After analyzing data from NASA’s InSight lander, an international team of researchers noticed that its seismometer, SEIS, detected six nearby seismic events. These were linked to the same acoustic atmospheric signal that meteorites generate when whizzing through the atmosphere of Mars. Further investigation identified all six as part of an entirely new class of quakes known as VF (very high frequency) events.

The collisions that generate VF marsquakes occur in fractions of a second, much less time than the few seconds it takes tectonic processes to cause quakes similar in size. This is some of the key seismological data that has helped us understand the occurrence of earthquakes caused by meteoric impacts on Mars. This is also the first time seismic data was used to determine how frequently impact craters are formed.

Enlarge / A skeleton found during 1950's excavations at the Barman site. (credit: Université de Genève)

Did ancient people practice equality? While stereotypes may suggest otherwise, the remains of one Neolithic society reveal evidence that both men and women, as well as locals and foreigners, were all equal in at least a critical aspect of life: what they ate.

The Neolithic saw the dawn of agriculture and animal husbandry some 6,000 years ago. In what is now Valais, Switzerland, the type and amount of food people ate was the same regardless of sex or where they had come from. Researchers led by Déborah Rosselet-Christ of the University of Geneva (UNIGE) learned this by analyzing isotopes in the bones and teeth of adults buried in what is now called the Barmaz necropolis. Based on the 49 individuals studied, people at the Barmaz site enjoyed dietary equality.

“Unlike other similar studies of Neolithic burials, the Barmaz population appears to have drawn its protein resources from a similar environment, with the same access to resources for adults, whether male or female,” the researchers said in a study recently published in the Journal of Archaeological Science: Reports.

Enlarge / The Milky Way's central black hole is in a very crowded neighborhood. (credit: UMass/D.Wang/NASA/STScI)

Supermassive black holes are ravenous. Clumps of dust and gas are prone to being disrupted by the turbulence and radiation when they are pulled too close. So why are some of them orbiting on the edge of the Milky Way’s own supermassive monster, Sgr A*? Maybe these mystery blobs are hiding something.

After analyzing observations of the dusty objects, an international team of researchers, led by astrophysicist Florian Peißker of the University of Cologne, have identified these clumps as potentially harboring young stellar objects (YSOs) shrouded by a haze of gas and dust. Even stranger is that these infant stars are younger than an unusually young and bright cluster of stars that are already known to orbit Sgr A*, known as the S-stars.

Finding both of these groups orbiting so close is unusual because stars that orbit supermassive black holes are expected to be dim and much more ancient. Peißker and his colleagues “discard the en vogue idea to classify [these] objects as coreless clouds in the high energetic radiation field of the supermassive black hole Sgr A*,” as they said in a study recently published in Astronomy & Astrophysics.

Enlarge (credit: CHOKSAWATDIKORN / SCIENCE PHOTO LIBRARY)

The hydra is a Lovecraftian-looking microorganism with a mouth surrounded by tentacles on one end, an elongated body, and a foot on the other end. It has no brain or centralized nervous system. Despite the lack of either of those things, it can still feel hunger and fullness. How can these creatures know when they are hungry and realize when they have had enough?

While they lack brains, hydra do have a nervous system. Researchers from Kiel University in Germany found they have an endodermal (in the digestive tract) and ectodermal (in the outermost layer of the animal) neuronal population, both of which help them react to food stimuli. Ectodermal neurons control physiological functions such as moving toward food, while endodermal neurons are associated with feeding behavior such as opening the mouth—which also vomits out anything indigestible.

Even such a limited nervous system is capable of some surprisingly complex functions. Hydras might even give us some insights into how appetite evolved and what the early evolutionary stages of a central nervous system were like.

Enlarge / The echidna, an egg-laying mammal, doesn't develop teeth. (credit: Yvonne Van der Horst)

Outliers among mammals, monotremes lay eggs instead of giving birth to live young. Only two types of monotremes, the platypus and echidna, still exist, but more monotreme species were around about 100 million years ago. Some of them might possibly be even weirder than their descendants.

Monotreme fossils found in refuse from the opal mines of Lightning Ridge, Australia, have now revealed the opalized jawbones of three previously unknown species that lived during the Cenomanian age of the early Cretaceous. Unlike modern monotremes, these species had teeth. They also include a creature that appears to have been a mashup of a platypus and echidna—an “echidnapus.”

Fossil fragments of three known species from the same era were also found, meaning that at least six monotreme species coexisted in what is now Lightning Ridge. According to the researchers who unearthed these new species, the creatures may have once been as common in Australia as marsupials are today.

Enlarge / Later theropods had multiple adaptations to varied temperatures. (credit: SCIEPRO/SCIENCE PHOTO LIBRARY)

Dinosaurs were once assumed to have been ectothermic, or cold-blooded, an idea that makes sense given that they were reptiles. While scientists had previously discovered evidence of dinosaur species that were warm-blooded, though what could have triggered this adaptation remained unknown. A team of researchers now think that dinosaurs that already had some cold tolerance evolved endothermy, or warm-bloodedness, to adapt when they migrated to regions with cooler temperatures. They also think they’ve found a possible reason for the trek.

Using the Mesozoic fossil record, evolutionary trees, climate models, and geography, plus factoring in a drastic climate change event that caused global warming, the team found that theropods (predators and bird ancestors such as velociraptor and T. rex) and ornithischians (such as triceratops and stegosaurus) must have made their way to colder regions during the Early Jurassic. Lower temperatures are thought to have selected for species that were partly adapted to endothermy.

“The early invasion of cool niches… [suggests] an early attainment of homeothermic (possibly endothermic) physiology in [certain species], enabling them to colonize and persist in even extreme latitudes since the Early Jurassic,” the researchers said in a study recently published in Current Biology.