Category: 7. Science

Shortly after the Big Bang the universe was a hot, dense soup of particles. After a few seconds, it became cool enough for the first elements to form, mainly ionized hydrogen and helium. Around 380,000 years later, things had finally cooled enough for these ionized elements to combine with free electrons and form the first neutral atoms in the universe.

This led to a much more exciting period in the cosmos, facilitating the first chemical reactions. The universe was about to get its first molecule: the helium hydride ion (HeH⁺), composed of a neutral helium atom and an ionized hydrogen nucleus. 

“The first molecules were formed in the radiative association process H+ + He → HeH⁺ + hν,” the team explains in their paper, “and subsequently other small molecular ions and neutral molecules were formed, among them H₂⁺, H₂, H₃⁺, LiH, LiH⁺, and deuterated variants of those species.”

In this early stage of the universe, HeH⁺ and H² (molecular hydrogen or deuterium, the most abundant molecule in the universe) played important roles in cooling protostar clouds enough for them to collapse enough to begin fusion. 

“Simulations have shown that the existence of molecules is crucial at this stage. At temperatures below 10,000 K, the level spacing in all of the light atoms is too large to provide the necessary cooling (through photon emission) for a primordial protostar to collapse. Vibrational and rotational degrees of freedom in molecules, on the other hand, enable radiative cooling down to much lower temperature,” the team explains. “With a substantial dipole moment of 1.66 debye, the HeH⁺ ion becomes a valid cooling candidate.”

In new experiments, the team attempted to recreate the conditions of the early universe, and test whether HeH⁺ could provide the cooling needed to form the universe’s first stars. The team bombarded the molecule with deuterium at varying temperatures, simulated by varying the relative speed of the beams of particles. To their surprise, and contrary to previous predictions, the reaction rate did not slow as temperatures significantly decreased.

“Previous theories predicted a significant decrease in the reaction probability at low temperatures, but we were unable to verify this in either the experiment or new theoretical calculations by our colleagues,” Dr Holger Kreckel from the Max-Planck-Institut für Kernphysik (MPIK) explained in a statement. “The reactions of HeH⁺ with neutral hydrogen and deuterium therefore appear to have been far more important for chemistry in the early universe than previously assumed.”

These results could have profound implications for our understanding of the early universe, and may even force a bit of reevaluation. 

“Measurements at the [cryogenic storage ring] have recently shown that the electron recombination rate is very slow for rotationally cold HeH⁺ ions,” the team concludes. “Combined with the present finding, it is apparent that reactions of HeH⁺ with atomic hydrogen are more important for primordial molecular abundances than was previously assumed and that reevaluations of helium chemistry in the early Universe – as well as very recent modeling efforts of HeH⁺ detections in planetary nebulae – may be called for.”

The study is published in Astronomy & Astrophysics.

Scientists from The University of Manchester, in a collaboration led by ETH Zurich and including TU Wien and ICFO Barcelona, have achieved a major breakthrough by cooling the spinning motion of a nanoparticle to its quantum ground state, the coldest possible state of motion.

The study, published in Nature Physics, and carried out at ETH Zurich, demonstrates how researchers used a finely tuned laser and vacuum system to trap and cool a 100-nanometre glass disc composed of billions of atoms. The work sets a new benchmark for quantum purity, a measure of how closely a system behaves according to the rules of quantum mechanics.

Dr. Jayadev Vijayan, a Research Fellow in the Department of Electrical and Electronic Engineering at The University of Manchester, explains: “This high-purity quantum state of motion gives us the best starting point to test whether objects 10,000 times heavier than the current record-holder show wave-like behaviour characteristic of the quantum world.”

A new cold source for quantum experiments

In the quantum world, atoms can behave like both particles and waves at the same time, appearing to being “in two places at once” – an effect that only happens in the quantum world.

To observe these effects in larger objects, their motion must be cooled close to absolute zero – where the only remaining motion is due to quantum fluctuations, the jittering of empty space itself.

To achieve this for the first time, researchers used a laser beam to trap a nanoparticle and make it levitate inside a vacuum chamber. The vacuum chamber removes all the air, so nothing can bump into the particle and heat it up. Next, they placed the particle between two mirrors facing each other, forming a cavity to cool the motion of the particle.

Professor Carlos Gonzalez-Ballestero, Institute of Theoretical Physics at TU Wien, explains: “The laser can either supply energy to the nanoparticle or take energy away from it. By carefully adjusting the cavity mirrors, we can make sure that the laser almost always takes energy away. The particle then spins slower and slower until it reaches the quantum ground state.”

What makes this result remarkable is the record-breaking purity of the quantum state. High purity means the object is behaving in a way that is almost entirely quantum, with very little influence from the environment. That level of control and precision opens doors to experimental tests of quantum mechanics at completely new scales.

Putting large quantum systems to use

This breakthrough creates a pathway to revolutionary new technologies. The larger a quantum object is, the more sensitive it becomes to certain types of forces, potentially making them incredibly sensitive quantum sensors. For example, levitated nanoparticle-based sensors could provide: a new type of precise navigation system that does not need global satellite systems; early detection systems for earthquakes and volcanic activity; and mapping tools for subterranean topology.

University of Warwick astronomers have uncovered compelling evidence that a nearby white dwarf is in fact the remnant of two stars merging — a rare stellar discovery revealed through Hubble Space Telescope ultraviolet observations of carbon in the star’s hot atmosphere.

White dwarfs are the dense cores left behind when stars exhaust their fuel and collapse. They are Earth-sized stellar embers weighing typically half as much as the Sun, made up of carbon-oxygen cores with surface layers of helium and hydrogen. While white dwarfs are common in the universe, those with exceptionally high mass (weighing more than the Sun) are rare and enigmatic.

In a paper published today in Nature Astronomy , Warwick astronomers report on their investigations of a known high-mass white dwarf 130 light-years away, called WD 0525+526. With a mass 20% larger than our Sun, WD 0525+526 is considered “ultra-massive”, and how this star came to be is not fully understood.

Such a white dwarf could form from the collapse of a massive star. However, ultraviolet data from the Hubble Space Telescope revealed WD 0525+526 to have small amounts of carbon rising from its core into its hydrogen-rich atmosphere — suggesting this white dwarf did not originate from a single massive star.

“In optical light (the kind of light we see with our eyes), WD 0525+526 looks like a heavy but otherwise ordinary white dwarf,” said first author Dr Snehalata Sahu, Research Fellow at the University of Warwick. “However, through ultraviolet observations obtained with Hubble, we were able to detect faint carbon signatures that were not visible to optical telescopes.

“Finding small amounts of carbon in the atmosphere is a telltale sign that this massive white dwarf is likely to be a be the remnant of a merger between two stars colliding. It also tells us there may be many more merger remnants like this masquerading as common pure-hydrogen atmosphere white dwarfs. Only ultraviolet observations would be able to reveal them to us.”

Normally, hydrogen and helium form a thick barrier-like envelope around a white dwarf core, keeping elements like carbon hidden. In a merger of two stars, the hydrogen and helium layers can burn off almost completely as the stars combine. The resulting single star has a very thin envelope that no longer prevents carbon from reaching the surface — this is exactly what is found on WD 0525+526.

Antoine Bédard, Warwick Prize Fellow in the Astronomy and Astrophysics group at Warwick and co-first author said, “We measured the hydrogen and helium layers to be ten-billion times thinner than in typical white dwarfs. We think these layers were stripped away in the merger, and this is what now allows carbon to appear on the surface.

“But this remnant is also unusual: it has about 100,000 times less carbon on its surface compared to other merger remnants. The low carbon level, together with the star’s high temperature (nearly four times hotter than the Sun), tells us WD 0525+526 is much earlier in its post-merger evolution than those previously found. This discovery helps us build a better understand the fate of binary star systems, which is critical for related phenomena like supernova explosions.”

Adding to the mystery is how carbon reaches the surface at all in this much hotter star. The other merger remnants are later in their evolution and cool enough for convection to bring carbon to the surface. But WD 0525+526 is far too hot for that process. Instead, the team identified a subtler form of mixing called semi-convection, seen here for the first time in a white dwarf. This process allows small amounts of carbon to slowly rise into the star’s hydrogen-rich atmosphere.

“Finding clear evidence of mergers in individual white dwarfs is rare,” added Professor Boris Gänsicke, Department of Physics, University of Warwick, who obtained the Hubble data for this study. “But ultraviolet spectroscopy gives us the ability to detect these signs early, when the carbon is still invisible at optical wavelengths. Because the Earth’s atmosphere blocks ultraviolet light, these observations must be carried out from space, and currently only Hubble can do this job.

“Hubble just turned 35 years old, and while still going strong, it is very important that we start planning for a new space telescope that will eventually replace it.”

As WD 0525+526 continues to evolve and cool, it is expected that more carbon will emerge at its surface over time. For now, its ultraviolet glow offers a rare glimpse into the earliest stage of a stellar merger’s aftermath — and a new benchmark for how binary stars end their lives.

Chinese scientists from the Agricultural Genomics Institute at Shenzhen have revealed that the potato came from a chance natural interbreeding event between the ancestors of today’s tomatoes and those of a closely related group called Etuberosum.

The breakthrough, which came from an international project including input from taxonomy and evolutionary biology experts at the Natural History Museum, has discovered that the ancient roots of one of the world’s most important crops started with an extraordinary chance natural interbreeding event between two wild plants nine million years ago.

The discovery uncovers a missing piece of the potato’s evolutionary history and solves the mystery of where the world’s third most important staple crop comes from. The answers gleaned from this study means that scientists can turn the potato into a seed crop, with much faster breeding efficiency and a better resistance to disease and climate change.

The team analysed 450 potato genomes (including many domestic varieties) and 56 wild relatives to solve the mystery of why modern potato plants look very similar to the wild species of the Etuberosum group (despite the latter not carrying the structure we eat – the tubers) but are evolutionarily-speaking more closely related to tomatoes in some parts of their genomes. The analysis confirmed that the potato carries a balanced genetic legacy from its two ancestors, with key genes inherited from each that together made tuber formation possible.

One gene – SP6A, a signal for tuberisation – came from the tomato side of the family. But it was only when paired with IT1 – a gene regulating underground stem growth from Etuberosum – that the potato was able to evolve the thick, starchy underground storage organ we know today.

This evolutionary leap occurred as the Andes mountains were rapidly rising in a period of major environmental change caused by the Atlantic plate pushing beneath the South American plate. Phylogenetic analysis of today’s members of the two ‘parent plant’ lineages show how they each occupy distinct environmental niches: tomatoes (dry and hot) and Etuberosum (temperate).

Lead author of the study, Zhiyang Zhang, of the Agricultural Genomics Institute at Shenzhen, commented, “Wild potatoes are very difficult to sample, so this dataset represents the most comprehensive collection of wild potato genomic data ever analysed.”

Dr Sandy Knapp, botany researcher at the Natural History Museum and co-author, added, “Science never stops – it keeps asking the next interesting question. The group behind this study came together to see how we can use insights from evolution to speed up and improve breeding of cultivated and domesticated potatoes globally.

“By combining genomic excellence with an understanding of the 107 species of wild potatoes and their distribution, which comes from specimens held in collections like those at the Museum, the team have been able to uncover the very functional underpinning of the heightened diversification of the potato plant lineage – which is quite extraordinary.”

Dr Tiina Särkinen, a nightshade expert at the Royal Botanic Garden Edinburgh and another co-author, said: “These results make us look at our humble potato in a very different light: potato and all its wild relatives came to exist thanks to a chance encounter of two very different individuals. That’s actually quite romantic. The origin of many of our species isn’t a simple story, and it’s very exciting that we can now discover these tangled, complex origins thanks to the wealth of genomic data.”

Dawn Aerospace and Scout Space have completed their first demonstration flight carrying a space domain awareness (SDA) payload, marking a significant first step toward SDA capability using a sub-orbital spaceplane at supersonic speeds . The flight tested integration of Scout’s ‘Morning Sparrow’ sensor suite aboard the Aurora platform, flying from a conventional runway at Tawhaki National Aerospace Centre in New Zealand.

This flight also marks Scout as the first commercial operator to fly on Dawn Aerospace’s Aurora – a rocket-powered high-altitude aircraft, under a strategic partnership in which Scout will develop a first-of-its-kind tactically responsive Very Low Earth Orbit (VLEO) space domain awareness capability. The combination of supersonic flight testing and runway-based operations gives Scout a unique, accelerated path to proving new SDA technologies that are easier, more repeatable and more affordable.

‘Morning Sparrow’, flew to a maximum altitude of 67,000 ft, and maximum speed of Mach 1.03. In follow-on flights, Morning Sparrow’s sensor suite will then be used to gather data and demonstrate the sensor’s capability to track and image VLEO objects from below—offering a responsive platform for urgent, time-sensitive intelligence-gathering and a cost-efficient alternative to conventional satellite-based SDA.

“Rapidly deployable, high-performance, high-altitude platforms are notoriously few and far between.” said Philip Hover-Smoot, CEO of Scout Space. “Accelerating flexible access to VLEO represents a leap forward in how we think about  taskable surveillance and space security in rapidly evolving low orbit environments, and unlocks new options for operators looking for otherwise limited intelligence products across the increasingly important VLEO regime.”

The sensor, housed in the Aurora’s payload bay, was accessible up to moments before flight showcasing the ease of integration, rapid access, and easy hardware adjustments for space-class optics into aircraft-grade environments. Shortly after Aurora landing back on the runway, the crew had already begun transferring flight data, demonstrating the kind of rapid turnaround and responsiveness critical for SDA missions.

“This is exactly what the Aurora is designed for—repeatable, tactical access to near space, supporting payloads that can’t wait months or years for launch,” said Stefan Powell, CEO of Dawn Aerospace. “We believe spaceplanes can and will play an integral role in the future of responsive space operations by complementing traditional SDA assets.” 

Next Steps

• Scout and Dawn will continue their collaboration with a contract in place allowing Scout the option to fly Sparrow on Aurora for up to 30 flights.
• In parallel, Scout is developing two GEO-class Owl flight units for long-range object detection and autonomous SDA — extending its hosted-sensor heritage into full spacecraft operations.

By enabling high-cadence VLEO observation from suborbital altitudes, Scout’s approach could dramatically change how space is monitored by governments and commercial operators. Scout Space is well placed to lead this shift—demonstrating how urgent intelligence gathering for time-sensitive situations can be done faster and more flexibly than ever before.

A baby star is lighting up more than just its corner of space – it’s also revealing the raw ingredients that could eventually form life.

Astronomers have detected 17 complex organic molecules in the planet-forming disc around a young star called V883 Orionis. Among them are ethylene glycol and glycolonitrile – two molecules long suspected but never before seen in this kind of environment.

These findings come from a team at the Max Planck Institute for Astronomy (MPIA), using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.

The study offers new insight into how life’s chemistry might emerge well before planets fully form.

Star stirs up organic soup

V883 Orionis isn’t an ordinary young star. It’s in the middle of a growth spurt, pulling in gas and blasting out intense energy.

The outburst temporarily heats its surrounding disc of dust and ice, releasing complex molecules that frozen grains usually trap. These molecules become visible to astronomers using tools like ALMA, which can detect the radio signals they emit.

“Complex molecules, including ethylene glycol and glycolonitrile, radiate at radio frequencies,” said MPIA scientist Kamber Schwarz. “ALMA is perfectly suited to detect those signals.”

The detected molecules include precursors to amino acids like glycine and alanine, and even adenine, one of the building blocks of DNA. Ethylene glycol – the same compound used in antifreeze – also plays a role in prebiotic chemistry.

“We recently found ethylene glycol could form by UV irradiation of ethanolamine, a molecule that was recently discovered in space,” said Tushar Suhasaria, co-author and head of MPIA’s Origins of Life Lab.

“This finding supports the idea that ethylene glycol could form in those environments, but also in later stages of molecular evolution, where UV irradiation is dominant.”

Origins of life-friendly chemistry

Scientists have long wondered when and where life-friendly chemistry begins – and whether it starts before a star fully forms.

For a while, the assumption was that dramatic transitions – like the shift from a protostar to a fully formed star – would wipe out fragile organic molecules.

That led to a theory called the “reset” model, where any life-forming compounds would have to rebuild from scratch in newly forming planetary discs. But new evidence from V883 Orionis challenges that idea.

“Our finding points to a straight line of chemical enrichment and increasing complexity between interstellar clouds and fully evolved planetary systems,” said Abubakar Fadul of MPIA.

Star formation doesn’t erase life

Instead of being erased, complex molecules may survive early star formation and carry over into planet-forming regions.

“Now it appears the opposite is true,” explained Schwarz. “Our results suggest that protoplanetary discs inherit complex molecules from earlier stages, and the formation of complex molecules can continue during the protoplanetary disc stage.”

That would mean the seeds of biology – like amino acids, sugars, and nucleobases – are not just possible in one solar system but likely common across the universe.

How stars trigger molecule release

The chemistry behind these molecules starts small and cold. Dust grains in space act like tiny laboratories, where atoms and simple molecules stick to icy surfaces and gradually become more complex. These ice-bound compounds are nearly impossible to detect – unless something heats them up.

That’s where young stars like V883 Orionis come in. When the star pulls in more gas, it emits powerful radiation that warms even the outer parts of its disc.

“These outbursts are strong enough to heat the surrounding disc as far as otherwise icy environments, releasing the chemicals we have detected,” said Fadul.

The heating process is similar to what happens with comets in our own Solar System. As they approach the Sun, their icy surfaces vaporize, forming visible tails and releasing trapped organic molecules.

The search for life’s chemistry isn’t over

The MPIA team knows there’s more to uncover. Though this discovery is major, their spectral data still holds mysteries.

“While this result is exciting, we still haven’t disentangled all the signatures we found in our spectra,” said Schwarz. “Higher resolution data will confirm the detections of ethylene glycol and glycolonitrile – and maybe even reveal more complex chemicals we simply haven’t identified yet.”

“Perhaps we also need to look at other regions of the electromagnetic spectrum to find even more evolved molecules,” noted Fadul. “Who knows what else we might discover?”

Universe favors life’s chemistry

Finding these complex organic molecules in a young star’s disc reinforces a bigger idea: the universe might have wired itself chemically for life from the start.

If molecules like these are common in planet-forming regions, then life-friendly chemistry could be happening everywhere – and not just by chance.

This doesn’t mean we’ve found life, or even direct evidence of it. But it does mean the starting materials are out there, hiding in the ice, waiting for a star to wake them up.

The full study was published in the journal The Astrophysical Journal Letters.

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White sharks (Carcharodon carcharias) almost went bottom-up during the last ice age, when sea levels were much lower than they are today and sharks had to get by with less space. The most recent cold snap ended about 10,000 years ago, and the planet has been gradually warming ever since. As temperatures increased, glaciers melted, and sea levels rose, which was good news for great whites.

Results of a study published in the journal Proceedings of the National Academy of Sciences show that white sharks had been reduced to a single, well-mixed population somewhere in the southern Indo-Pacific Ocean. White sharks began genetically diverging about 7,000 years ago, suggesting that they had broken up into two or more isolated populations by this time.

This is new information but not particularly surprising. There are never many white sharks around even at the best of times, as befits their status at the top of the tapered food chain, where a lack of elbow room limits their numbers. Today, there are three genetically distinct white shark populations: one in the southern hemisphere around Australia and South Africa, one in the northern Atlantic and another in the northern Pacific. Though widespread, the number of white sharks still remains low.

“There are probably about 20,000 individuals globally,” said study co-author Gavin Naylor, director of the Florida Program for Shark Research at the Florida Museum of Natural History. “There are more fruit flies in any given city than there are great white sharks in the entire world.”

Organisms with small populations can be pushed dangerously close to the edge of extinction when times are tough. Mile-high glaciers extended from the poles and locked away so much water that by 25,000 years ago, sea levels had plunged by about 40 meters (131 feet), eliminating habitat and restricting great whites to an oceanic corral.

But something happened to great whites during their big comeback that remains as much of a mystery now as it was when it was first discovered more than 20 years ago. The primary motivation for this study was to lay out a definitive explanation, but despite using one of the largest genetic datasets on white sharks ever compiled, things did not go quite according to plan.

“The honest scientific answer is we have no idea,” Naylor said.

Female great white sharks wander off for years to feed but come back home to breed

Scientists first got a whiff of something strange in 2001, when a research team published a paper that opened with the line, “… information about … great white sharks has been difficult to acquire, not least because of the rarity and huge size of this fish.”

The authors of that study compared genetic samples taken from dozens of sharks in Australia, New Zealand and South Africa. They found that though the DNA produced and stored in the nuclei of their cells were mostly the same between individuals, the mitochondrial DNA of sharks from South Africa were distinctly different from those in Australia and New Zealand.

The seemingly obvious explanation was that great whites tend to stick together and rarely make forays into neighboring groups. Over time, unique genetic mutations would have accumulated in each group, which, if it went on long enough, would result in the formation of new species.

This would explain the observed differences in their mitochondrial DNA but not why the nuclear DNA was virtually identical among all three populations. To account for that, the authors suggested that male sharks traveled vast distances throughout the year, but females either never traveled far, or if they did, they most often came back to the same place during the breeding season, a type of migration pattern called philopatry.

This idea was based on the fact that nuclear and mitochondrial DNA are not inherited in equal proportion in plants and animals. The DNA inside nuclei is passed down by both parents to their offspring, but only one — most often the female — contributes mitochondria to the next generation. This is a holdover from the days when mitochondria were free-living bacteria, before they were unceremoniously engulfed and repurposed by the ancestor of eukaryotes.  

This was a good guess and had the added benefit of later turning out to be mostly accurate. Male and female great whites do travel large distances in search of food throughout the year, and females consistently make the return journey before it’s time to mate.

Thus, the nuclear DNA of great whites should have less variation, because itinerant males go around mixing things up, while the mitochondrial DNA in different populations should be distinct because philopatric females ensure all the unique differences stay in one place. This has remained the favored explanation for the last two decades, one that seemed to fit like a well-worn glove. Except, no one ever got around to actually putting it on to test its size. This is primarily because the data needed to do so was hard to get for the same reasons mentioned in the touchstone study: There aren’t many great white sharks, and when researchers do manage to find one, taking a DNA sample without losing any appendages in the process can be tricky business.

Shark migration cannot explain nuclear and mitochondrial discordance, so what can?

Naylor and his colleagues began collecting the necessary data back in 2012. “I wanted to get a white shark nuclear genome established to explore its molecular properties,” he said. “White sharks have some very peculiar attributes, and we had about 40 or 50 samples that I thought we could use to design probes to look at their population structure.”

Over the next few years, they also sequenced DNA from about 150 white shark mitochondrial genomes, which are smaller and less expensive to assemble than their nuclear counterparts. The samples came from all over the world, including the Atlantic, Pacific and Indian oceans.

When they compared the two types of DNA, they found the same pattern as the one discovered in 2001. At the population level, white sharks in the North Atlantic rarely mixed with those from the South Atlantic. The same was true of sharks in the Pacific and Indian oceans. At a molecular level, the nuclear DNA among all white sharks remained fairly consistent, while the mitochondrial DNA showed a surprising amount of variation.

The researchers were aware of the philopatric theory and ran a few tests to see if it held up, first by looking specifically at the nuclear DNA. If the act of returning to the same place to mate really were the cause of the strange mitochondrial patterns, some small signal of that should also show up in the nuclear DNA, of which females contribute half to their offspring.

“But that wasn’t reflected in the nuclear data at all,” Naylor said.

Next, they concocted a sophisticated test for the mitochondrial genomes. To do this, they first had to reconstruct the recent evolutionary history of white sharks, which is how they discovered the single southern population they’d been reduced to during the last ice age.

“They were really few and far between when sea levels were lowest. Then the population increased and moved northward as the ice melted. We suspect they remained in those northern waters because they found a reliable food source,” Naylor said. Specifically, they encountered seals, which are a dietary staple among white sharks and one of the main reasons why they have such a strong fidelity to specific locations.

“These white sharks come along, get a nice blubbery sausage. They fatten up, they breed, and then they move off around the ocean.”

Knowing when the sharks split up was key, as each group would have begun genetically diverging from each other at this time. All the researchers had to do was determine whether the 10,000 years between now and the last ice age would have been enough time for the mitochondrial DNA to have accumulated the number of differences observed in the data if philopatry was the primary culprit.

They ran a simulation to find the answer, which came back negative. Philopatry is undoubtedly a behavioral pattern among great whites, but it was not responsible for the large mitochondrial schism.

So Naylor and his colleagues went back to the drawing board to figure out what sort of evolutionary force could account for the differences.

“I came up with the idea that sex ratios might be different — that just a few females were contributing to the populations from one generation to the next,” Naylor said. This type of reproductive skew can be observed in a variety of organisms, including meerkats, cichlid fish and many types of social insects.

But yet another test showed that reproductive skew did not apply to white sharks.

There is a third, albeit less likely, option the team members said they can’t rule out at this stage, namely that natural selection is responsible for the differences. The reason why this is far-fetched has to do with the relative strength of evolutionary forces. Natural selection — the idea that the organisms best suited to leave behind offspring will, in fact, generally be the ones that have the most offspring — is always active, but it has the strongest effect in large populations. Smaller populations, in contrast, are more susceptible to something called genetic drift, in which random traits — even harmful ones — have a much higher chance of being passed down to the next generation.

Florida panthers, for example, are highly endangered, with only a few hundred individuals left in the wild. Most of them have a kink at the end of their tail, likely inherited from a single ancestor. In a large population, subject primarily to natural selection, this trait would have either remained uncommon or disappeared entirely over time. But in a small population, a single cat with a kinked tail can change the world purely by chance through the auspices of genetic drift.

By way of comparison, gravity exerts a force at all scales of matter and energy, but it is by far the weakest of the four fundamental physical forces. At the scale of planets and stars, gravity can hold solar systems and galaxies together, but it has very little influence on the shape or interactions of atoms, which are governed by the three stronger but more localized forces, such as electromagnetism.

According to the study’s results, genetic drift cannot explain the differences between mitochondria in great whites. Because it is a completely random process, it cannot selectively target one type of DNA and spare another. If it were the culprit, similar changes would also be evident in the nuclear DNA.

This leaves natural selection as the only other possibility, which seems unlikely because of the small population sizes among white sharks. If it is the causative agent, Naylor said, the selective force “would have to be brutally lethal.”

If you collect enough mass in a concentrated space, say on the order of a black hole, the otherwise benign force of gravity becomes powerful enough to devour light.

If natural selection is at play in this case, it would manifest itself in a similarly powerful way. Any deviation from the mitochondrial DNA sequence most common in a given population would likely be fatal, thus ensuring it was not passed on to the next generation.

But this is far from certain, and Naylor has his doubts about the validity of such a conclusion. For now, scientists are left with an open-ended question that can only be resolved with further study.

Reference: Laso-Jadart R, Corrigan SL, Yang L, et al. A genomic test of sex-biased dispersal in white sharks. Proc Natl Acad Sci USA. 2025;122(32):e2507931122. doi: 10.1073/pnas.2507931122

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The Tintina fault is a major geologic fault approximately 1,000 km long that trends northwestward across the entire territory. It has slipped laterally a total of 450 km in its lifetime but was previously believed to have been inactive for at least 40 million years. However, using new high-resolution topographic data collected from satellites, airplanes and drones, researchers have identified a 130-km-long segment of the fault near Dawson City where there is evidence of numerous large earthquakes in the much more recent geologic past (the Quaternary Period, 2.6 million years to present), indicating possible future earthquakes.

“Over the past couple of decades there have been a few small earthquakes of magnitude 3 to 4 detected along the Tintina fault, but nothing to suggest it is capable of large ruptures,” says Theron Finley, recent UVic PhD graduate and lead author of the recent article in Geophysical Research Letters. “The expanding availability of high-resolution data prompted us to re-examine the fault, looking for evidence of prehistoric earthquakes in the landscape.”

Currently, the understanding of earthquake rates and seismic hazard in much of Canada is based on a catalogue of earthquakes from oral Indigenous accounts, written historical records and modern seismic monitoring networks. Collectively, these records only cover the last couple hundred years. However, for many active faults, thousands of years can elapse between large ruptures.

When earthquakes are large and/or shallow, they often rupture the Earth’s surface and produce a linear feature in the landscape known as a fault scarp. These features, which can persist in the landscape for thousands of years, are typically tens to hundreds of kilometers long, but only a few metres wide and tall. They are difficult to detect in heavily forested regions like Canada, and require extremely high-resolution topographic data to identify.

The team, consisting of researchers from UVic, the Geological Survey of Canada and University of Alberta, used high resolution topographic data from the ArcticDEM dataset from satellite images, as well as from light detection and ranging (lidar) surveys conducted with airplanes and drones. They identified a series of fault scarps passing within 20 km of Dawson City.

Crucially, they observed that glacial landforms 2.6 million years in age are laterally offset across the fault scarp by 1000 m. Others, 132,000 years old, are laterally offset by 75 m. These findings confirm that the fault has slipped in multiple earthquakes throughout the Quaternary period, likely slipping several meters in each event. What’s more, landforms known to be 12,000 years old are not offset by the fault, indicating no large ruptures have occurred since that time. The fault continues to accumulate strain at an average rate of 0.2 to 0.8 millimetres per year, and therefore poses a future earthquake threat.

“We determined that future earthquakes on the Tintina fault could exceed magnitude 7.5,” says Finley. “Based on the data, we think that the fault may be at a relatively late stage of a seismic cycle, having accrued a slip deficit, or build-up of strain, of six meters in the last 12,000 years. If this were to be released, it would cause a significant earthquake.”

An earthquake of magnitude 7.5 or greater would cause severe shaking in Dawson City and could pose a threat to nearby highways and mining infrastructure. Compounding the hazard from seismic shaking, the region is prone to landslides, which could be seismically triggered. The Moosehide landslide immediately north of Dawson City and the newly discovered Sunnydale landslide directly across the Yukon River both show ongoing signs of instability.

Canada’s National Seismic Hazard Model (NSHM) includes the potential for large earthquakes in central Yukon Territory, but the Tintina fault is not currently recognized as a discrete seismogenic fault source. The recent findings by this team will ultimately be integrated into the NSHM, which informs seismic building codes and other engineering standards that protect human lives and critical infrastructure. The findings will also be shared with local governments and emergency managers to improve earthquake readiness in their communities.

This research occurred on the territory of the Tr’ondëk Hwëch’in and Na-Cho Nyäk Dun First Nations

KUNMING – A team of Chinese researchers has discovered a new dinosaur assemblage from the Lower Jurassic period in Wuding county, Southwest China’s Yunnan province, representing the oldest sauropodomorph found in East Asia, according to a recent article published in the journal Scientific Reports.

In 2020, a previously unknown dinosaur assemblage was found in the Lower Jurassic strata at Wande town in Wuding county. The researchers from the Institute of Vertebrate Paleontology and Paleoanthropologyc (IVPP), the Geological Museum of China, Yunnan University and the local natural resources bureau spent five years restoring and studying the fossils, ultimately naming the species Wudingloong.

The Wudingloong fossil consists of relatively well-preserved cranial bones, cervical and dorsal vertebrae, and forelimb bones.

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Both the phylogenetic analysis and stratigraphic horizon indicate that Wudingloong represents the earliest-diverging and stratigraphically oldest sauropodomorph dinosaur discovered in East Asia so far, said You Hailu, a researcher at the IVPP.

This dinosaur dates back to the earliest period of the Early Jurassic, about 200 million years ago, You added.

Building on previous research, this study developed a novel phylogenetic character matrix.

Compared with other named sauropodomorphs in East Asia, Wudingloong is notably smaller, with smoother tooth enamel, a more slender scapula, a higher radius-to-humerus length ratio, and longer fingers, suggesting it was likely a bipedal dinosaur.

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The discovery of this new taxon adds to the evidence that the sauropodomorph assemblage in Southwestern China ranks among the most taxonomically diverse and morphologically varied of the Early Jurassic worldwide, according to the research article.