Category: 7. Science

Summary: A large-scale global study shows that extreme heat affects not just our bodies, but also our emotions. Researchers analyzed over a billion social media posts and found that when temperatures exceeded 95°F (35°C), expressed sentiments became more negative, particularly in lower-income countries where effects were three times stronger.

The findings highlight how rising global temperatures shape daily emotional experiences worldwide. Looking ahead, climate models suggest that by 2100, extreme heat alone could worsen global emotional well-being by 2.3%.

Key Facts

• Scale of Analysis: 1.2 billion posts across 65 languages from 157 countries.
• Heat Effect: Sentiment became 25% more negative in lower-income countries vs. 8% in higher-income ones.
• Future Projection: By 2100, extreme heat could reduce global emotional well-being by 2.3%.

Source: MIT

Rising global temperatures affect human activity in many ways. Now, a new study illuminates an important dimension of the problem: Very hot days are associated with more negative moods, as shown by a large-scale look at social media postings.

Overall, the study examines 1.2 billion social media posts from 157 countries over the span of a year. The research finds that when the temperature rises above 95 degrees Fahrenheit, or 35 degrees Celsius, expressed sentiments become about 25 percent more negative in lower-income countries and about 8 percent more negative in better-off countries. Extreme heat affects people emotionally, not just physically.

“Our study reveals that rising temperatures don’t just threaten physical health or economic productivity — they also affect how people feel, every day, all over the world,” says Siqi Zheng, a professor in MIT’s Department of Urban Studies and Planning (DUSP) and Center for Real Estate (CRE), and co-author of a new paper detailing the results.

“This work opens up a new frontier in understanding how climate stress is shaping human well-being at a planetary scale.”

The paper, “Unequal Impacts of Rising Temperatures on Global Human Sentiment,” is published today in the journal One Earth.

The authors are Jianghao Wang, of the Chinese Academy of Sciences; Nicolas Guetta-Jeanrenaud SM ’22, a graduate of MIT’s Technology and Policy Program (TPP) and Institute for Data, Systems, and Society; Juan Palacios, a visiting assistant professor at MIT’s Sustainable Urbanization Lab (SUL) and an assistant professor Maastricht University; Yichun Fan, of SUL and Duke University; Devika Kakkar, of Harvard University; Nick Obradovich, of SUL and the Laureate Institute for Brain Research in Tulsa; and Zheng, who is the STL Champion Professor of Urban and Real Estate Sustainability at CRE and DUSP. Zheng is also the faculty director of CRE and founded the Sustainable Urbanization Lab in 2019.

Social media as a window

To conduct the study, the researchers evaluated 1.2 billion posts from the social media platforms Twitter and Weibo, all of which appeared in 2019. They used a natural language processing technique called Bidirectional Encoder Representations from Transformers (BERT), to analyze 65 languages across the 157 countries in the study.

Each social media post was given a sentiment rating from 0.0 (for very negative posts) to 1.0 (for very positive posts). The posts were then aggregated geographically to 2,988 locations and evaluated in correlation with area weather. From this method, the researchers could then deduce the connection between extreme temperatures and expressed sentiment.

“Social media data provides us with an unprecedented window into human emotions across cultures and continents,” Wang says.

“This approach allows us to measure emotional impacts of climate change at a scale that traditional surveys simply cannot achieve, giving us real-time insights into how temperature affects human sentiment worldwide.”

To assess the effects of temperatures on sentiment in higher-income and middle-to-lower-income settings, the scholars also used a World Bank cutoff level of gross national income per-capita annual income of $13,845, finding that in places with incomes below that, the effects of heat on mood were triple those found in economically more robust settings.

“Thanks to the global coverage of our data, we find that people in low- and middle-income countries experience sentiment declines from extreme heat that are three times greater than those in high-income countries,” Fan says. “This underscores the importance of incorporating adaptation into future climate impact projections.”

In the long run

Using long-term global climate models, and expecting some adaptation to heat, the researchers also produced a long-range estimate of the effects of extreme temperatures on sentiment by the year 2100.

Extending the current findings to that time frame, they project a 2.3 percent worsening of people’s emotional well-being based on high temperatures alone by then — although that is a far-range projection.

“It’s clear now, with our present study adding to findings from prior studies, that weather alters sentiment on a global scale,” Obradovich says.

“And as weather and climates change, helping individuals become more resilient to shocks to their emotional states will be an important component of overall societal adaptation.”

The researchers note that there are many nuances to the subject, and room for continued research in this area. For one thing, social media users are not likely to be a perfectly representative portion of the population, with young children and the elderly almost certainly using social media less than other people.

However, as the researchers observe in the paper, the very young and elderly are probably particularly vulnerable to heat shocks, making the response to hot weather possible even larger than their study can capture.

The research is part of the Global Sentiment project led by the MIT Sustainable Urbanization Lab, and the study’s dataset is publicly available. Zheng and other co-authors have previously investigated these dynamics using social media, although never before at this scale.

“We hope this resource helps researchers, policymakers, and communities better prepare for a warming world,” Zheng says.

Funding: The research was supported, in part, by Zheng’s chaired professorship research fund, and grants Wang received from the National Natural Science Foundation of China and the Chinese Academy of Sciences. 

About this temperature and mood research news

Author: Peter Dizikes
Source: MIT
Contact: Peter Dizikes – MIT
Image: The image is credited to Neuroscience News

Original Research: Closed access.
“Unequal impacts of rising temperatures on global human sentiment” by Jianghao Wang et al. One Earth

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Abstract

Unequal impacts of rising temperatures on global human sentiment

Climate change poses growing risks to human well-being, yet research on its emotional impact has primarily focused on developed nations, obscuring potential global inequalities in psychological vulnerability.

Here, we analyze over 1.2 billion social media posts from 157 countries to reveal how rising temperatures affect human sentiment worldwide and project future impacts under climate scenarios.

We find a non-linear relationship where moderate warming can improve sentiment in cooler regions, but temperatures above 35°C negatively impact emotional well-being globally, with effects three times greater in low- and middle-income countries (25.0% decline in sentiment) than in high-income countries (8.1%).

Even accounting for climate adaptation through income growth, we project global average sentiment will be 2.3% lower in 2100 than in 2019 due to future warming, indicating lasting psychological costs disproportionately burdening the world’s poorest populations.

These findings underscore the urgent need for climate policies that integrate emotional impacts and address inequalities in psychological climate vulnerability.

Sweet potato DNA decoded, revealing hybrid ancestry. Discovery aids future breeding and resilience.

The sweet potato is a staple food for millions of people worldwide, particularly in sub-Saharan Africa, where its ability to withstand climate extremes makes it essential for food security. Despite its importance, the crop’s genetic makeup has remained elusive for decades. Scientists have now succeeded in decoding its highly complex genome, uncovering a detailed evolutionary history and creating valuable resources to guide future crop improvement.

Unlike humans, who inherit two sets of chromosomes, sweetpotatoes carry six. This condition, known as hexaploidy, has made interpreting its genome especially difficult—similar to trying to organize six overlapping sets of encyclopedias that have been thoroughly mixed together.

A research team led by Professor Zhangjun Fei at the Boyce Thompson Institute has now overcome this challenge. As reported in Nature Plants, they used state-of-the-art DNA sequencing and other advanced methods to assemble the first fully resolved genome of ‘Tanzania,’ a sweet potato variety widely valued in Africa for its resistance to disease and its high dry matter content.

Solving the chromosome puzzle

The biggest obstacle was to sort through the plant’s 90 chromosomes and reconstruct them into their six original groups, known as haplotypes. The researchers accomplished a complete separation, or “phasing,” of this intricate genetic puzzle—an achievement never before reached.

“Having this complete, phased genome gives us an unprecedented level of clarity,” said Fei. “It allows us to read the sweet potato’s genetic story with incredible detail.”

What they uncovered was unexpectedly complex. The sweetpotato genome turned out to be a patchwork formed from several wild ancestors, some of which remain unknown. Roughly one-third of its genetic makeup derives from Ipomoea aequatoriensis, a wild species native to Ecuador that appears to be a direct descendant of an early sweetpotato ancestor. Another major portion closely resembles a Central American wild species known as Ipomoea batatas 4x, although the true contributor may still be unrecognized in the wild.

“Unlike what we see in wheat, where ancestral contributions can be found in distinct genome sections,” says Shan Wu, the study’s first author, “in sweetpotato, the ancestral sequences are intertwined on the same chromosomes, creating a unique genomic architecture.”

Evolutionary advantages of polyploidy

This intertwined genetic heritage means that sweetpotato can be tentatively classified as a “segmental allopolyploid”—essentially a hybrid that arose from different species but behaves genetically as if it came from a single one. This genomic merging and recombination gives sweet potato its remarkable adaptability and disease resistance, traits crucial for subsistence farmers worldwide.

“The sweetpotato’s six sets of chromosomes also contribute to its enhanced resilience,” adds Fei. “With multiple versions of important genes, the plant can maintain backup copies that help it survive drought, resist pests, and adapt to different environments—a feature known as polyploid buffering.”

Broader applications for agriculture

However, achieving a full understanding of sweetpotato’s genetic potential will require decoding multiple varieties from different regions, as each may carry unique genetic features that have been lost in others.

The work by Fei and his team represents more than just an academic milestone. Equipped with a clearer understanding of sweet potato’s complex genetics, breeders can now more efficiently identify genes responsible for key traits like yield, nutritional content, and resistance to drought and disease. This precision could accelerate the development of improved varieties.

Beyond sweetpotato, this research demonstrates how modern genomic tools can help decode other complex genomes. Many important crops, including wheat, cotton, and banana, have multiple sets of chromosomes.

As climates shift and pest and disease pressures increase, understanding these genetic puzzles is critical for breeding resilient crops and addressing challenges in food security.

Reference: “Phased chromosome-level assembly provides insight into the genome architecture of hexaploid sweetpotato” by Shan Wu, Honghe Sun, Xuebo Zhao, John P. Hamilton, Marcelo Mollinari, Gabriel De Siqueira Gesteira, Mercy Kitavi, Mengxiao Yan, Hongxia Wang, Jun Yang, G. Craig Yencho, C. Robin Buell and Zhangjun Fei, 8 August 2025, Nature Plants.
DOI: 10.1038/s41477-025-02079-6

Funding: Bill and Melinda Gates Foundation, National Institute of Food and Agriculture

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Hundreds of millions of years ago, Earth’s first forests helped pump oxygen into the deep seas, transforming once-barren waters into thriving habitats.

This permanent oxygen boost allowed fish with jaws and other marine animals to expand, diversify, and grow larger, sparking a revolution in ocean life.

Colonizing the Deep Seas

Around 390 million years ago, marine animals began moving into deep ocean zones that had previously been uninhabited. New research suggests this expansion was made possible by a lasting rise in deep-sea oxygen levels, fueled by the spread of woody plants on land (the early ancestors of Earth’s first forests).

This long-term oxygen increase took place during a remarkable burst of diversity among jawed fish, the group that would eventually give rise to nearly all vertebrates living today. The evidence points to oxygenation as a potential driver of evolutionary shifts in these ancient species.

Tracking Ancient Oxygenation

“It’s known that oxygen is a necessary condition for animal evolution, but the extent to which it is the sufficient condition that can explain trends in animal diversification has been difficult to pin down,” said co-lead author Michael Kipp, assistant professor of earth and climate sciences in the Duke University Nicholas School of the Environment. “This study gives a strong vote that oxygen dictated the timing of early animal evolution, at least for the appearance of jawed vertebrates in deep-ocean habitats.”

Scientists once believed that deep-ocean oxygenation occurred only once, at the start of the Paleozoic Era, roughly 540 million years ago. However, newer studies point to a stepwise pattern, beginning with oxygen making shallow coastal waters habitable and later extending into the deeper ocean.

Rock Clues From the Seafloor

Kipp and colleagues homed in on the timing of those phases by studying sedimentary rocks that formed under deep seawater. Specifically, they analyzed the rocks for selenium, an element that can be used to determine whether oxygen existed at life-sustaining levels in ancient seas.

In the marine environment, selenium occurs in different forms called isotopes that vary by weight. Where oxygen levels are high enough to support animal life, the ratio of heavy to light selenium isotopes varies widely. But at oxygen levels prohibitive to most animal life, that ratio is relatively consistent. By determining the ratio of selenium isotopes in marine sediments, researchers can infer whether oxygen levels were sufficient to support animals that breathe underwater.

Global Rock Samples and Analysis

Working with research repositories around the world, the team assembled 97 rock samples dating back 252 to 541 million years ago. The rocks had been excavated from areas across five continents that, hundreds of millions of years ago, were located along the outermost continental shelves — the edges of continents as they protrude underwater, just before giving way to steep drop-offs.

After a series of steps that entailed pulverizing the rocks, dissolving the resulting powder, and purifying selenium, the team analyzed the ratio of selenium isotopes that occurred in each sample.

Two Great Oxygenation Events

Their data indicated that two oxygenation events occurred in the deeper waters of the outer continental shelves: a transient episode around 540 million years ago, during a Paleozoic period known as the Cambrian, and an episode that began 393-382 million years ago, during an interval called the Middle Devonian, that has continued to this day. During the intervening millennia, oxygen dropped to levels inhospitable to most animals. The team published their findings in Proceedings of the National Academy of Sciences in August.

“The selenium data tell us that the second oxygenation event was permanent. It began in the Middle Devonian and persisted in our younger rock samples,” said co-lead author Kunmanee “Mac” Bubphamanee, a Ph.D. candidate at the University of Washington.

That event coincided with numerous changes in oceanic evolution and ecosystems — what some researchers refer to as the “mid-Paleozoic marine revolution.” As oxygen became a permanent feature in deeper settings, jawed fish, called gnathostomes, and other animals began invading and diversifying in such habitats, according to the fossil record. Animals also got bigger, perhaps because oxygen supported their growth.

Forests Rise, Oceans Change

The Middle Devonian oxygenation event also overlapped with the spread of plants with hard stems of wood.

“Our thinking is that, as these woody plants increased in number, they released more oxygen into the air, which led to more oxygen in deeper ocean environments,” said Kipp, who began this research as a Ph.D. student at the University of Washington.

The cause of the first, temporary oxygenation event during the Cambrian is more enigmatic.

“What seems clear is that the drop in oxygen after that initial pulse hindered the spread and diversification of marine animals into those deeper environments of the outer continental shelves,” Kipp said.

Lessons for Today’s Oceans

Though the team’s focus was on ancient ocean conditions, their findings are relevant now.

“Today, there’s abundant ocean oxygen in equilibrium with the atmosphere. But in some locations, ocean oxygen can drop to undetectable levels. Some of these zones occur through natural processes. But in many cases, they’re driven by nutrients draining off continents from fertilizers and industrial activity that fuel plankton blooms that suck up oxygen when they decay,” Kipp said.

A Warning Across Time

“This work shows very clearly the link between oxygen and animal life in the ocean. This was a balance struck about 400 million years ago, and it would be a shame to disrupt it today in a matter of decades.”

Reference: “Mid-Devonian ocean oxygenation enabled the expansion of animals into deeper-water habitats” by Kunmanee Bubphamanee, Michael A. Kipp, Jana Meixnerová, Eva E. Stüeken, Linda C. Ivany, Alexander J. Bartholomew, Thomas J. Algeo, Jochen J. Brocks, Tais W. Dahl, Jordan Kinsley, François L. H. Tissot and Roger Buick, 25 August 2025, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2501342122

Funding: MAK was supported by an NSF Graduate Research Fellowship and Agouron Institute Postdoctoral Fellowship. Additional support was provided by the NASA Astrobiology Institute’s Virtual Planetary Laboratory.

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On an overcast Tuesday in July, divers Mitch Johnson and Sean Taylor shimmy into their wetsuits on the back of the R/V Xenarcha, a 28ft boat floating off the coast of Rancho Palos Verdes, south of Los Angeles. Behind them, the clear waters of the Pacific are dotted with a forest of army-green strands, waving like mermaid hair underwater.

We are here to survey the giant Pacific kelp, a species that once thrived in these ice cold waters. But over the past two decades, a combination of warm ocean temperatures, pollution, overfishing and the proliferation of hungry sea urchins that devour the kelp has led to a 80% decline in the forest along the southern California coast.

In recent years, scientists have staged a comeback – mounting one of the largest and most successful kelp restoration projects in the world. To do so, they’ve recruited an army of hammer-wielding divers to smash and clean up the voracious urchins. Today’s trip is a chance to see that success up close.

video of kelp underwater

Seen from the boat’s edge, the kelp fronds are so thick and sturdy at places that they form mats at the ocean’s surface, sturdy enough for egrets and herons to perch on while they poked at the fish beneath. These waters host a multitude of species, from bright orange garibaldi fish and white sharks that silently cruise the coastline to blue whales which sail through the deep channel a few miles to our east.

Divers like Johnson and Taylor have a variety of tools at their disposal. Some days, they pick up rock hammers – like an underwater version of the seven dwarves – and dive to crack open the ravenous purple urchins that destroy the baby kelp. But today, they are armed only with a tape and a camera to survey the status of this gigantic concealed forest.

Gear on, the divers give a thumbs-up to Tom Ford, chief executive officer of the Bay Foundation, a non-profit dedicated to restoring Santa Monica Bay and its coastal waters, who is piloting the boat. With a small splash, they disappear into the water. Ford and I wait, with the quiet slapping of waves on the side of the Xenarcha, to see what they find.

Led by the Bay Foundation, divers in the Santa Monica Bay have spent 15,575 hours underwater over the past 13 years. To bring the kelp back, they focus on minimizing the impact of one voracious eater: the purple urchin. The effort has been successful, smashing 5.8 million purple urchins and clearing 80.7 acres (32.7 hectares, the size of 61 football fields), and allowing the kelp to return.

But with the results contained far offshore and underwater, has anyone noticed? Ford wonders the same thing. “We call it the forgotten forest,” he says.

Cathedrals in the sea

The fast-growing kelp ecosystems are known as the “sequoias of the sea” for good reason: they store large amounts of carbon, create habitat for more than 800 marine species and blunt the powerful force of storm waves. Technically, they are a macro-algae, and can grow as much as 2ft each day, reaching 100ft from reef bed to surface.

For those lucky enough to see the kelp from under the waves, it can feel like a fairytale – a forest, but instead of walking through it, you’re flying underwater.

Ford still remembers the first time he dived into the forest as a scuba diver. The sunlight looked like tongues of flame rippling through the blades from underwater, and the shafts of light peeked through the small holes in the canopy. “It looked like a cathedral, with light shooting through the stained glass,” he says. “And sometimes you float down through this and there’s thousands of fish of all sorts of colors just flitting around everywhere. It’s like flying through an unimaginably dense forest of life.”

a diver hammering urchins underwater

But for a time, these glorious environments were at risk of disappearing. When the Bay Foundation started working in these waters in 2012, the sea bed looked like carpets of purple – blanketed in endemic golf ball-sized spiky urchins.

It was a symptom of an ecosystem gone haywire, with multiple overlapping injuries: sea otters, which eat urchins as a staple of their diet, were almost wiped out by hunters in the 19th century. Then, from the 1940s to the 1970s, a large amount of DDT was discharged from a chemical plant into the sea off Palos Verdes. Sediment from landslides also buried the reefs in silt, preventing anything from growing. More recently, the local sea stars, which eat the urchins, were hit with a wasting disease, and turned to goo. All that was left was urchins, which eat kelp at an incredible rate, and scratched the reef bed so much that any kelp spores still circulating couldn’t grab a foothold.

Ford and the Bay Foundation did multiple tests to determine the optimal amount of urchins per square meter: two. Meanwhile, some areas of the barrens had 70-80 urchins per meter. Since they didn’t have much to eat, they were basically empty zombie urchins – hungry, empty of their meat, just hanging on and preventing kelp from growing. There was a lot to do.

The Bay Foundation applied for grants from the state and federal authorities and started hiring divers, gathering 75 volunteers, and even working with commercial fishers to help out. Ford points out that the team was not smashing the healthy urchins that people depend on for their livelihood. “We were paying the fishermen to put back the forest, and then they could then go back in and fish from there again,” he says.

That’s the case with Terry Herzik, a longtime red sea urchin fisher, who started working with the foundation in 2012, spending nine hours a day smashing urchins instead of collecting them for sale. “No one has more hours down there clearing urchins than Terry,” says Ford, gesturing to Herzik’s boat, the Sun Spot, which is anchored nearby. “We could not have achieved this without him.”

Slowly, methodically, divers ventured down out and smashed urchins week after week, clearing the plots. Hitting an urchin with a foot-long rock hammer gives “a satisfying crunch”, Johnson says. He is quick to point out that this is manual labor, just underwater (and while wearing a cumbersome scuba suit).

The divers talk about their job almost as if they are part of a construction crew – it’s repetitive work, but fulfilling, like filling potholes in the ocean. “You just tap, tap, and sometimes you have to reach into crevices to get the urchins out,” says Taylor. “Your forearms get super tired.”

But the real benefit is seeing how quickly the kelp returns when the urchins are under control – in some cases within a matter of months. That’s because the microscopic single-celled kelp spores are wafting in the water column all the time – much like seeds of a plant carried by the wind – waiting for the right conditions to attach to the reef and start growing.

Johnson remembers one spot along the coast that he worked on. “Within three months, the kelp came back,” he says. “I’ve never seen a kelp forest that dense – and it was insane to see how quickly it returned.”

With a little kelp from my friends

Taylor and Johnson, who both work for the Bay Foundation, resurface and haul themselves on to the back of the boat. Shaking the sea water out of their hair, they describe what they saw in the survey area: tons of fish, a small shark and a forest of green.

“There’s still a lot of kelp,” Johnson tells Ford, but it’s not all good news. “There’s still a pocket where the urchins are expanding out.” It’s still a mystery why some areas stay restored with kelp, while others return to barrens.

The boat moves on to another point on the coast, where the divers descend again. Here, the kelp forest is so thick that it forms a mat keeping the boat in place.

“I don’t know if we need to anchor,” Ford says. “I’ll just let the algae hold me.”

a close-up video of kelp

Ford and I lift up a kelp frond from the edge of the boat. It’s slippery, rubbery and slightly slimy. On the top, I can see a colony of bryozoans – tiny filter-feeding invertebrates that live on the surface of the kelp. Teensy shrimp and snails also gather on the fronds: evidence of its importance as a habitat for so many creatures. I run my fingers along the blades that are just starting to differentiate and grow the bulbs that keep the structure afloat. Even as a parent to fast-growing children, it’s hard to imagine the speed at which this algae moves – always upward, always out. “Everything flows from the kelp.” Ford says.

The project could be a model for other parts of the world where kelp is struggling. In Tasmania and South Korea, efforts are under way to save kelp. California’s Santa Barbara channel is also a target for future restoration work.

With blobs of warmer oceans in a climate-changed future, kelp may still be at risk – but there are hopeful signs. The sites that have been restored remain mostly intact. The foundation’s research shows that California spiny lobster have returned to the area, and fish such as kelp bass and sheepshead are more abundant now than before restoration work started. The kelp also improves water quality, absorbing excess nutrients, and keeps sediments in place in a similar way that trees hold the land from sliding after rains. And the improvements even benefited the valuable red sea urchins – in sites where the kelp has been restored, red sea urchin gonads (the prized parts, also known as uni) weigh 168% more.

While the effect of the urchins has been devastating, Ford points out that kelp has always faced challenges: from powerful waves that rip out the strands from the seabed, to summertime temperatures that kill off the nutrients needed to grow. That has made the kelp super-resilient – and ready to pounce at any opportunity to regrow. “Part of the reason why we see such a rapid response to the restoration is because the system has evolved to respond rapidly to beneficial conditions,” he says.

Perhaps the kelp will have a fairytale future after all – one that helps the planet, the people and the coastline into the next century.

The study finds life’s origin faces severe mathematical challenges. Chance alone may not be enough.

A new study addresses one of science’s most enduring questions: how did life first arise from nonliving matter on the early Earth? Using advanced mathematical methods, Robert G. Endres of Imperial College London developed a framework indicating that the spontaneous emergence of life may have been far more difficult than previously thought.

The research highlights the immense challenge of generating structured biological information under realistic prebiotic conditions, underscoring how unlikely it would have been for the first living cell to appear naturally. Think of it like trying to write an article about the origins of life for a well-renowned science website by randomly throwing letters at a page. The chances of success become astronomically small as the required complexity increases.

By applying information theory and algorithmic complexity, Endres analyzed what it would take for the earliest living cell, known as a protocell, to self-assemble from simple chemical components. This mathematical perspective demonstrates how improbable such a process would be if left to chance under natural conditions.

Barriers to life’s emergence

The findings indicate that chance alone, combined with natural chemical reactions, may not sufficiently account for the origin of life within the limited timeframe of early Earth. Because systems generally move toward disorder rather than order, the formation of the highly structured arrangements required for life faces serious barriers.

This does not imply that the emergence of life was impossible, but it suggests that current knowledge may be lacking. The research highlights that identifying the physical principles behind life’s rise from nonliving matter remains one of the greatest challenges in biological physics.

Considering alternative ideas

While maintaining scientific rigor, the paper acknowledges that directed panspermia, originally proposed by Francis Crick and Leslie Orgel, remains a speculative but logically open alternative. This hypothesis suggests that life might have been intentionally seeded on Earth by advanced extraterrestrial civilizations, though the author notes this idea challenges Occam’s razor, the scientific principle favoring simpler explanations.

This research doesn’t disprove the possibility of life emerging naturally on Earth, though. Instead, it quantifies the mathematical challenges involved and suggests that we may need to discover new physical principles or mechanisms that could overcome these informational barriers. The work represents an important step toward making the study of life’s origins more mathematically rigorous.

The study also reminds us that some of the universe’s greatest mysteries still await solutions, and that combining mathematical precision with biological questions can reveal new depths to age-old puzzles about our existence.

Reference: “The unreasonable likelihood of being: origin of life, terraforming, and AI” by Robert G. Endres, 24 July 2025, arXiv.
DOI: 10.48550/arXiv.2507.18545

Adapted from an article originally published on Universe Today.

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In CA 426’s exploration of the impact of the Viking Great Army on the north of England, we mentioned research that had shed light on the make-up of a Viking hoard discovered at Bedale, 56km (35 miles) from York. Here, we will dig deeper into this study, sharing its main findings (which were published in full in Archaeometry: https://doi.org/10.1111/arcm.70031) and exploring what they reveal about the probable provenances of the hoard.

The Bedale Hoard was discovered in 2012 by metal-detectorists and was subsequently excavated by Dr Adam Parker and Rebecca Griffiths of York Museums Trust. They recovered 36 silver objects and one gold sword pommel, all appearing to date to the Viking Age.

In order to explore the sources of this silver, a team led by Dr Jane Kershaw of the University of Oxford and involving researchers from the British Geological Survey examined geochemical information obtained from lead (Pb) isotope ratios and trace elements. It is known that the Vikings amassed silver and other precious metal ‘loot’ during their raids in western Europe, and they also established long-distance trade networks reaching as far as the Islamic Caliphate, along which they traded furs and slaves in exchange for silver coins known as dirhams. The relative importance of these sources of silver, however, was less clear.

The team used Pb isotope results to divide the Bedale artefacts into two groups. One comprised 14 objects which appear to have undergone cupellation – a refining process in which lead is added to precious metals and heated to extreme temperatures in order to remove non-noble metals. The other comprised 22 objects which had not been treated in this way. For elemental analysis, the team used both portable X-ray fluorescence (pXRF) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Tiny samples of material were also taken by drilling and analysed by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) in order to examine lead isotopes.

The results from these two analyses were then combined, revealing three different ‘sources’ for the refined (cupelled) silver. Among these objects, eight ingots and a ring are thought to have been refined using British lead and, based on the consistency of their isotope values, were probably cast at the same time. Because lead is added during the cupellation process, the original lead, which would point to the silver’s origin, is obscured. The team believe, however, that the source silver is unlikely to have come from the Islamic world as, during the 9th century, dirhams from this region were naturally low in gold and higher in bismuth. Carolingian and Anglo-Saxon coins, on the other hand, underwent a traceable change in gold content over the course of the 9th century. Early in the century, the coinage had low levels of gold which then steadily increased over the next 100 years, with the highest gold-to-silver ratios occurring after Alfred the Great’s coin reform in AD 875. The gold content in the eight items mentioned above is consistent with coins minted in western Europe during the mid- to late 9th century, which would have needed refining in order to raise their low silver content to acceptable levels.

The second set of objects made from refined silver – consisting of two neck-rings and an ingot – appears to have used lead from Melle in France (see CA 347, CA 411, and CA 412). Once again, the trace elements results are so similar that all three items were probably refined in the same location. This group also had gold and bismuth values that were more consistent with silver from Europe and particularly from Carolingian coinage of the mid-9th century. The last group of refined silver objects – two ingots – had Pb isotope ratios suggesting that they were made from a mixture of silver refined using British lead and silver from an eastern source.

Regarding the non-refined silver, the study identified two primary sources: one in western Europe and one in the Islamic world. Three items – the arm-ring, the bossed penannular brooch, and one ingot – were made using solely western European silver. Intriguingly, their isotope ratios are consistent with silver from the Galloway Hoard, which was deposited near Balmaghie in the early 10th century (CA 376); although the two collections were buried over 100 miles apart, it may be that they had a shared silver stock. In contrast, nine ingots appear to have been made from recycled Islamic coins, with their isotope signature consistent with dirhams deposited in Gotland hoards throughout the 9th century. They are not isotopically similar to Samanid dirhams, however, which came to dominate Scandinavian coin stocks by the end of the 9th century, indicating that they were most likely cast before this date. The last group of objects – made up of six ingots, two neck-rings, and the neck collar – had results falling on a continuum between the two, suggesting that they were made from a mix of the two sources.

Overall, the majority of the silver appears to have come from western sources or was mixed with western silver. While it may be that this silver stock arrived through trade, the researchers argue that this was probably from the ‘loot’ acquired during Viking raids across northern Europe from the 840s onwards. The presence of nine ingots made of Islamic silver – probably cast in Scandinavia – nevertheless demonstrates that the Vikings did not only take wealth out of England, they also brought it in.

Text: Kathryn Krakowka / Image: York Museums Trust