The two powerful earthquakes that struck Venezuela's northern coast, killing more than 180 people, were an event known as a "doublet."

Doublet earthquakes happen when a pair of similar-sized quakes hit close in location and time, according to the U.S. Geological Survey. On Wednesday evening, a 7.2 magnitude quake hit first, followed by a magnitude 7.5 just 39 seconds later.

The deadly one-two punch toppled buildings in Venezuela's capital, Caracas and beyond. Some 1,500 people were injured and thousands were reported missing. The coastal region of La Guaira, which is north of Caracas, experienced some of the heaviest damage and casualties, officials said.

How rare are doublets?
While not as common as a typical earthquake where a main shock is followed by much smaller aftershocks, doublets can happen anywhere in the world, Christine Goulet, director of the USGS earthquake science center in California, told The Associated Press.

Doublets indicate a complex fault structure, like the one in Venezuela. Known as the Bocono fault, it runs along the backbone of the Venezuelan Andes for about 300 miles (500 kilometers). A previous doublet—of magnitudes 6.2 and 6.3—struck an area west of Caracas in September 2025, killing at least one person and injuring more than 100 others. Most of the damage was reported in the states of Zulia and Lara.

The world's most powerful particle accelerator will shutter operations Monday for four years of renovations to dramatically boost its collision capacity and the potential for unlocking one of the greatest mysteries of the universe: dark matter.

The Large Hadron Collider (LHC)—a 27-kilometer (17-mile) proton-smashing circular tunnel at the heart of Europe's physics lab CERN near Geneva—has most famously been used to prove the existence of the Higgs boson, dubbed "the God particle."

In the tunnel, running about 100 meters (330 feet) below the French-Swiss border area, superconducting magnets and accelerating structures propel particles to extreme energies and then smash them together at phenomenal speeds.

But from Monday, activity will stop as the extraordinary device undergoes upgrades aimed at further increasing the precision and intensity of particle collisions.

Once completed, the enhanced particle smasher, bearing the new name High Luminosity LHC (HL-LHC), is scheduled to begin operations in June 2030 and to run for about a decade.

'Many discoveries' await
"This is a very important moment. From Monday, we will be entering a new phase," HL-LHC project chief Markus Zerlauth told reporters.

"We still have lots of physics questions without answers. There are still many discoveries to be made."

The goal is to increase the "luminosity"—that is, the total number of collisions produced over a given period—by a factor of 10 compared with the LHC.

⁣After 8 years travelling across the inner Solar System, BepiColombo has switched off its ion engines.
The ESA/JAXA mission is now entering its final approach to Mercury, with key arrival steps starting in September.

🔗 esa.int/Enabling_Suppo…

A policy paper argues that NASA’s planned moon base should include a biocontainment facility to help protect Earth from potentially hazardous biological contaminants brought back from space.

“Humanity is entering a new era of space exploration, but our planetary protection strategies have not kept pace with the risks associated with returning extraterrestrial samples to Earth,” said paper coauthor Frederick I. Moxley, Director of Strategic Threat Analysis and Research Laboratories, an Idaho-based consultancy.

“The proposed facility would essentially act as a firewall between Earth and any potentially hazardous live organisms that could accompany returning future space missions,” said Moxley, whose coauthor is Anthony Ricciardi, a James McGill Professor of Biology and the Director of the Bieler School of Environment at McGill University.

Samples would stop on the moon
In their paper, published in Ambio, Moxley and Ricciardi argue that material gathered from the moon, Mars or farther destinations should not be sent straight to Earth. Instead, they say extraterrestrial samples should first go to a secure quarantine and research facility on the moon.

Moxley and Ricciardi recommend that all incoming space samples be handled only by advanced robotic systems inside the lunar facility. That approach would reduce the chances of human exposure or an accidental release.

Invasive species offer a warning
Although no extraterrestrial life has been confirmed, Moxley and Ricciardi warn that any unfamiliar form of life entering Earth’s biosphere could have unpredictable ecological effects. They point to Earth’s long history of invasive species as a cautionary example.

Neanderthals lived in Europe and western Asia from at least around 430,000 years ago until around 40,000 years before present.

The high-quality nuclear genomes of four Neanderthals provided numerous insights into the diversity and population history of Neanderthals and their interactions with early modern humans.

The more recent Neanderthal from Croatia (45,000 years ago) showed higher genetic diversity and less evidence of recent inbreeding than do the older Neanderthals from Denisova and Chagyrskaya caves (120,000, approximately 110,000, and approximately 60,000 years ago) who lived in the easternmost part of the known Neanderthal range.
...
“The late Neanderthals from northwestern Europe appear to have been part of a connected regional population, rather than small, isolated groups with frequent mating between close relatives.”

Although modern humans had arrived in the region by around 47,000 years ago, none of the Neanderthal genomes showed traces of recent human DNA.

“Our results add to a striking asymmetry,” Bossoms Mesa said.

“We repeatedly find Neanderthal ancestry in early modern humans, but so far, we have not found clear evidence of recent modern human ancestry in late Neanderthals.”

The scientists also tested the theory that Neanderthals were gradually weakened by accumulating genetic defects.

Comparing early and late Neanderthals, they found no meaningful increase in harmful mutations over time, undermining the notion that genetic deterioration drove their extinction.

What ultimately doomed the Neanderthals remains an open question.

Researchers at the University of Chicago Pritzker School of Molecular Engineering (UChicago PME) have created a skin-like computing patch that can process health data using artificial intelligence directly on the body. Unlike conventional wearable devices, the patch performs AI calculations in milliseconds without needing to send information over a wireless connection.

Most smartwatches can monitor metrics such as heart rate and movement, but the actual data analysis takes place on external servers. That delay can be problematic in situations where every millisecond matters, such as detecting ventricular fibrillation, a life-threatening heart rhythm disorder.

Developed and tested with researchers at Argonne National Laboratory, the new device was made possible by manufacturing techniques that allow organic electrochemical transistors to be printed onto flexible materials.

“The future that we’re trying to realize is to make wearable and implantable devices smarter,” said Sihong Wang, an associate professor of molecular engineering at UChicago PME and co-senior author of the new study, published in Nature Electronics. “It’s helping people have a personal, instantaneous doctor integrated into their devices.”

Stretchable Neuromorphic Computing for Human Tissues
Wang’s laboratory has spent years developing electronic components that can stretch and flex like human skin, with the goal of creating intelligent devices that can attach directly to biological tissues. Previous achievements included stretchable transistor arrays and a stretchable OLED display.

For this project, the researchers aimed to build a stretchable neuromorphic computing circuit, a large network of transistors capable of analyzing health information. Earlier studies had shown that the idea could work with a limited number of transistors, but scaling it to a practical system remained a challenge.

What if consciousness has nothing to do with flesh and blood?

The possibility may sound like science fiction, but it is becoming an increasingly serious philosophical question as scientists search for alien life and artificial intelligence grows more sophisticated. A new analysis argues that consciousness may not be unique to Earth’s biology and could, in principle, emerge in life forms built from entirely different materials.

Eric Schwitzgebel, a distinguished professor of philosophy at the University of California, Riverside, and Jeremy Pober, a former UCR graduate student now a postdoctoral researcher at the University of Lisbon, contend that there is little reason to think conscious experience is tied exclusively to carbon-based life. Instead, they argue, consciousness could arise wherever evolution, or something like it, produces the right kind of complex system.

Rather than attempting to define consciousness itself, the researchers begin with the assumption that it is a real phenomenon. From there, they explore a deceptively simple question: Must consciousness depend on the biology found on Earth, or could it take forms unlike anything humanity has ever encountered?

Their paper arrives as debates over conscious artificial intelligence grow more urgent, inspiring both hopeful visions and alarming scenarios. Schwitzgebel and Pober address AI only briefly and do not offer a shared conclusion. In fact, their views differ. Still, their argument leaves room for the possibility that AI could be conscious someday, even if current systems may not be.

The central idea in the paper is “substrate flexibility.” A property is substrate flexible when it can be produced by more than one type of material. A cup, for example, can be made from glass, plastic or many other substances. A book can exist on paper or in digital form. Music can be stored on vinyl or compact discs.

Schwitzgebel and Pober argue that consciousness may work in a similar way.

“The universe may contain minds stranger than we can imagine,” Schwitzgebel said.

Uranus and Neptune remain two of the most mysterious objects in the solar system, primarily because they’ve only been visited by NASA’s Voyager 2 spacecraft in 1986 and 1989, respectively. Their “ice giant” moniker comes from longstanding hypotheses that their interiors are comprised of an icy mantle beneath their hydrogen/helium atmospheres. While Jupiter and Saturn are also comprised primarily of hydrogen and helium, Uranus and Neptune are hypothesized to have a layered structure comprised of icy elements within their interiors.

Despite decades of models, studies, and hypotheses, the debate over the longtime “ice giant” nickname for Uranus and Neptune is heating up. This is because a recently submitted study to The Astrophysical Journal could show this nickname might not be as frozen solid as scientists have long believed. In either case, a team of researchers from the University of California, Los Angeles (UCLA) could cause longstanding scientific passions to melt away.

For the study, the researchers used a series of computer models to simulate and ascertain the interior compositions and processes of Uranus and Neptune. The primary motivation behind the study was to confirm or refute the longstanding models and hypotheses regarding the “ice giant” status of Uranus and Neptune. While long standing models have given both worlds a hydrogen/helium atmosphere covering a vast mantle of “ices” comprised of water, ammonia, and methane, and finally a rocky core, studies into both worlds’ magnetic fields and heat distribution have puzzled scientists.

The researchers note that not only could this study explain the interiors of Uranus and Neptune, but that they could be used as analogs for sub-Neptune exoplanets. They are the most common type of exoplanet in our galaxy and have radii between 1 to 4.5 of Earth. Due to a lack of similar planet in our solar system, the formation and evolution of these exoplanets remain a mystery.

In the end, this study determined that the interiors of Uranus and Neptune are potentially comprised of a magma ocean, as opposed to an icy composition. The planetary layers the study proposes include a hydrogen/helium atmosphere that transports heat to the upper atmosphere and radiates it to space. Below this layer is a boundary layer comprised of several elements, including hydrogen, helium, magnesium, silicon monoxide (SiO), and oxygen. Finally, the bottom layer is a magma ocean comprised of silicate, iron, and hydrogen.

During several recent conversations, people have told me that they've stopped checking their phones in the morning. Not because nothing was happening, but because everything was. They described the feeling as standing under a waterfall of perpetual bad news.

This experience is far from an isolated one. According to Reuters Institute's 2025 Digital News Report, 69% of Canadians at least occasionally avoid the news now.

Globally, 40% report they at least sometimes or often do the same, the highest figure ever recorded. People shared consistent reasons for this: the news put them in a bad mood, they felt overwhelmed and powerless to act.

As a researcher in developmental psychology, focusing on social development and psychological well-being, I argue that news fatigue is not laziness, weakness or a generational decline in civic interest. It's the predictable response of a human brain meeting an environment it was never designed to navigate.

Wired for bad news
Long before smartphones or even the printing press, our cognitive architecture was shaped by a single problem: stay alive long enough to reproduce. Our ancestors whose attention drifted past the rustle in the grass left fewer descendants than those who froze, looked and listened.

The brain that paid attention to threats was the brain that survived.

This is the foundation of what psychologists call the negativity bias, one of the most replicated findings in cognitive science. Across decades of research, the human mind has been shown to weigh negative information more heavily than positive, attend to it faster and remember it longer.

A University of Alberta research team has designed a promising alternative for treating antimicrobial-resistant infections, a pressing global health issue. In a paper recently published in Cell Biomaterials, the team describes preclinical testing results for its human-derived peptide treatment, D-GK17. The peptide is stable and nontoxic to humans and is synthesized to attack the surfaces of bacterial or fungal cells that create biofilms, a sticky matrix that is often impenetrable to antibiotic treatments.

"Antimicrobial resistance is the biggest pandemic threatening humanity, so we really need potent antibiotic alternatives to which bacteria are unable to develop resistance," says principal investigator Dr. Prasanna Neelakantan, associate professor in the Mike Petryk School of Dentistry and Alberta Dental Association & College Chair in Oral Health Research, who did the work with collaborators at the University of Hong Kong and the University of Pennsylvania.

"Our peptide shredded bacterial biofilms, which cause up to 75% of life-threatening infections," Neelakantan explains. "We used skin infection models to show how our antibiotic alternative not only rescues from devastating bacterial infections, but also reduces inflammation and promotes wound healing."

Antimicrobial resistance is estimated to have directly caused 1.27 million deaths and contributed to 4.95 million deaths in 2019, according to the World Health Organization.

The team's treatment is based on a human-produced host defense peptide that provides rapid, broad-spectrum protection against bacteria, viruses and fungi. Most such peptides are toxic in the high concentrations needed to eradicate biofilms, and more importantly, they are unstable in body fluids, so it has been hard to harness their power as drugs.

The team serendipitously discovered a small subunit of the human peptide LL-37 known as GK17 that is stable and nontoxic, first publishing its findings three years ago.

"It checked the box for killing bacteria and fungi. It checked the box for preventing the development of resistance. But one box that it did not check was whether it could eradicate biofilms, which would be critical. So, we made a mirror version of our peptide, hoping it would break down biofilms," Neelakantan says.

They tested it against the biofilms created by the so-called ESKAPE group of the world's most critical pathogens, and it worked.

Why does the Sun throw stuff at us?

The Sun’s surface is a churning soup of energetic electrons and ions called plasma.

The motion of those charged particles creates magnetic field loops that are larger than the Earth. These loops twist, turn, and trap plasma.

The featured time-lapse, taken over 2 hours on April 24th, 2026 by the Solar Dynamics Observatory, shows what happens when those magnetic fields become too stressed: they snap and expel billions of tons (trillions of kilograms) of plasma into space at millions of miles (or kilometers) per hour in what is called a coronal mass ejection (CME).

The Sun releases a few CMEs each day when it is at the peak of its activity cycle, which passed in 2025. Some of these eruptions hit Earth and can disrupt power grids, disable satellites, and endanger astronauts, which is why space weather monitoring is so important.

Artificial intelligence is being adopted across policing and the wider criminal justice system of England and Wales faster than the rules designed to govern it, according to major new research published by Northumbria University.

The study—the most comprehensive mapping exercise of its kind to date—identifies 70 AI tools already deployed, trialed or under development across the criminal justice system, from contact-center triage and witness statement drafting to digital forensics and facial recognition.

Led by Northumbria University in partnership with the Universities of Glasgow, Northampton, Leicester, Newcastle and Cambridge, the four-year PROBabLE Futures project was funded by Responsible AI UK as a 4.2 million-pound Keystone Project. The team spent the past year building an interactive mapping tool and conducting interviews between May 2025 and January 2026 with police officers, government officials, legal professionals, oversight bodies, academics and technology vendors.

Of the 70 tools identified, 27 are already live, with around 34 at the trial or pilot stage. More than half, 52%, come from commercial vendors, with most activity concentrated at the community policing, intelligence and investigation stages of the criminal process.

The research delivers a clear central finding: AI is already generating real value in transcription, redaction, crime analysis, vulnerability identification and officer welfare—but only where it has been carefully designed, matched to clearly defined operational problems and robustly evaluated. Across the wider system, adoption is outpacing the institutional, evidential and governance frameworks needed to support it.

A particular focus of the report is the concept of the "human in the loop"—the principle that a person should review and remain accountable for AI outputs. The research finds this principle often exists in name only, providing a false sense of assurance rather than a genuine safeguard.

The report also highlights a counterintuitive risk: As a tool approaches near-perfect accuracy, people may stop checking its outputs, meaning rare errors are more likely to go undetected and carry serious consequences. This danger grows when AI systems are linked together in sequence, with each stage potentially inheriting and compounding errors introduced earlier.

Even a relatively small asteroid can have a surprisingly dramatic history. During a close flyby of the asteroid Donaldjohanson, NASA’s Lucy spacecraft discovered an oddly shaped world that wobbles through space, bears scars from an ancient collision, and even preserves evidence that liquid water briefly existed on its parent body long ago.

The asteroid formed about 155 million years ago when fragments from a violent impact slowly came back together. Since then, sunlight has steadily altered its rotation through a subtle but powerful process, leaving behind clues to its long and eventful evolution.

Lucy’s Close Encounter With Donaldjohanson
On April 20, 2025, Lucy flew within 650 miles of Donaldjohanson while traveling through the main asteroid belt on its way to the Jupiter Trojan asteroids. The spacecraft captured the first detailed images and scientific measurements of this previously unexplored object.

Rather than rotating around a single axis like most planets and asteroids, Donaldjohanson was found to have a much more complicated motion involving two separate rotational movements. The flyby also revealed its distinctive peanut-like shape along with numerous craters and ridges covering its surface.

The encounter served as a full-scale rehearsal before Lucy begins exploring the Trojan asteroids, starting with its flyby of Eurybates on Aug. 12, 2027. Everything aboard the spacecraft operated as planned, while scientists gained an unexpected opportunity to compare Donaldjohanson with two better-known asteroids, Bennu and Ryugu. Those two bodies have similar compositions but followed very different evolutionary paths after their formation.

The Lucy team’s initial findings were published June 18 in the journal Science.

Sound does not fossilize, making it difficult to trace the vocal origins of song, speech, and language,” said University of Warwick researcher Chiara De Gregorio and colleagues.

“Comparative studies of the behavior of (non-human) great apes — our closest living relatives — provide the only extant model of extinct vocal capacities and adaptive functions among human ancestors.”

“While all major branches of the hominid family have evolved distinct call repertoires shaped by their species-specific socio-ecologies, one vocalization has been conserved across species and age-sex classes: laughter.”

In the study, the researchers recorded laughter from 17 individuals across all five great ape species in both tickling and social play situations.

The study involved four orangutans, two gorillas, three bonobos, four chimpanzees, and four humans, including children between six months and seven years old.

Their analysis revealed that laughter across all species is isochronous — that is, the bursts occur at regular, evenly spaced intervals — a property also observed in music and speech rhythm.

According to the scientists, this basic rhythmic structure was already present in a shared common ancestor 15 million years ago and has remained remarkably conserved with all living great apes still show the same underlying pattern.

But they also found meaningful differences along the evolutionary tree: as species grow closer to humans on the family tree, their laughter becomes faster, more variable in timing, and more sensitive to social context.

Humans stood out as the only species to adjust their laughter tempo depending on whether they were being tickled or engaged in free play.

The authors also noted that in human laughter, variable timing is perceived as more emotionally warm and socially positive than rigid, robotic-sounding laughter, suggesting that rhythmic flexibility carries real social meaning.

Despite continual habitability headlines, the debate over whether Mars ever had or currently has life still rages. At every new planetary conference, someone presents data that often for a few weeks at least appears to change the calculus of Martian astrobiology. But for well over two decades now, one of the biggest mysteries remains --- the origin of the putative methane detections made by the Tunable Laser Spectrometer (TLS) on NASA's Curiosity rover which has repeatedly reported several detections of methane.

This methane flap actually began with the European Space Agency’s Mars Express spacecraft which started orbital science operations in 2004. During Mars Express’ first year of observations and analysis, a small spectrometer on the spacecraft detected a very low-resolution spectral bump which indicated the tenuous infrared absorption of methane in the red planet’s atmosphere.

Yet the detections were at the limits of the instrument’s (the Planetary Fourier Spectrometer) sensitivity, ESA notes.

It's not that convincing, but at the very same time, two different independent research groups using ground-based telescopes were also claiming that they could see Mars methane through Earth's atmosphere, Kevin Olsen, a planetary scientist at the University of Oxford and a co-investigator of the ExoMars Trace Gas Orbiter's Atmospheric Chemistry suite instrument, told me in the U.K.

Habitability is the key.

The most important thing people care about is whether Mars has been or is habitable, and whether there's microbial life, and in the atmosphere the big thing is methane, which we don't see, says Olsen.

As for the ExoMars TGO?
The Trace Gas Orbiter primary objective is to definitively detect trace gasses such as compounds with sulfur, chlorine, and methane.

If methane is coming from a biosphere, then either living things are producing methane as they go about their daily life and use energy, says Olsen. Or maybe they're not living anymore, and there remains an ancient source of biologically created methane.

If methane is not coming from a biological source; then the most likely thing is active rock metamorphosis, he says.

This is where rock changes from one type into another, which would happen deep underground, at high pressure, with lots of heat, water and chemical energy. But after eight years of observations with TGO’s instruments working at nominal levels, the ESA team still has not found evidence for methane.

We have a thousand times better sensitivity than the Mars sample analysis suite on NASA’s Curiosity rover, but we do not see any sign of the absorption of methane in the Martian atmosphere, says Olsen.

Every time electricity flows through a wire, some of its energy is inevitably lost as heat because electrons collide with one another and with the material around them. But just how much can these collisions increase electrical resistance? A new study suggests there is a fundamental limit.

To investigate, researchers from the University of Toronto, L’École Normale Supérieure in Paris, and Lehigh University turned to an unusual stand-in for electrons: ultracold potassium atoms cooled to temperatures just above absolute zero.

By precisely controlling how often the atoms collided, they found that resistance increased only up to a certain point before leveling off. The discovery provides rare experimental evidence for a microscopic limit to resistivity and could improve scientists’ understanding of electron behavior in quantum materials.

“Electron-on-electron collisions are known to increase resistivity in some pure materials,” explains Professor Joseph Thywissen in the Department of Physics and the Center for Quantum Information and Quantum Control in the Faculty of Arts & Science at the University of Toronto, senior author of a study published in Physical Review Letters. “The energy produced by electrical resistance shows up as heat. Transmission lines, for instance, lose up to 8% of the generated electrical power. Resistivity is also interesting to study because it can be a signature of new physics in materials.”

The smallest centipedes have 30 legs, while the largest ever discovered had 382 👀
🐛 Despite the name, no centipede with exactly 100 legs has ever been found. Surprising science explains why!

The liver is one of the body’s hardest-working organs, carrying out hundreds of vital jobs, from filtering toxins and metabolizing medications to producing proteins essential for blood clotting. Yet when it fails, the only definitive treatment is often a transplant, a solution limited by a chronic shortage of donor organs.

MIT engineers have now developed injectable “mini livers” that, in mice, survived for at least two months while performing many of the functions of healthy liver tissue.

“We think of these as satellite livers. If we could deliver these cells into the body, while leaving the sick organ in place, that would provide booster function,” says Sangeeta Bhatia, the John and Dorothy Wilson Professor of Health Sciences and Technology and of Electrical Engineering and Computer Science at MIT, and a member of MIT’s Koch Institute for Integrative Cancer Research and the Institute for Medical Engineering and Science (IMES).

or the very first time, biologists packed nonliving components into a cell-like membrane, piece by piece, and witnessed the bag of molecules start to behave like life. The lab-made synthetic cell grew, replicated its DNA, and divided, demonstrating the basic functions of a cell cycle.

It’s “an impressive step,” said Jack Szostak, who studies the origins of life at the University of Chicago and was not involved in the research. “I don’t know of any other effort to put together an artificial cell from biological components that has progressed so far.”

The cell is not alive by any definition. It can’t survive without constant deliveries of food and ribosomes, the machinery needed to make proteins. It has no defenses or a good waste removal system. But it’s the strongest demonstration yet that it is possible to generate life from nonlife, a goal that synthetic biologists have been chasing for decades.

“It’s a big step forward to this holy grail of making a living thing out of dead components,” said Sijbren Otto, a systems chemist at the Stratingh Institute for Chemistry in the Netherlands who was not involved in the work. “It’s not completely there yet, but it’s definitely getting quite close.”

Since these cells were pieced together from scratch, and all the molecular parts were crafted in the lab, scientists can tinker with the system and switch components in and out. “I have a blueprint, I have a full chemical ingredient list of every component,” said Kate Adamala, a synthetic biologist at the University of Minnesota who led the new study, which is not yet peer-reviewed. With such flexibility, this kind of synthetic cell could eventually be coaxed to create new materials, such as biofuels and drugs, and help researchers study disease.

A study is reframing a fundamental question in plant evolution: What made trees possible? Researchers from Cal Poly Humboldt, Yale University, the University of Hohenheim in Germany and the Czech Academy of Sciences set out to understand how trees evolved and what allowed them to become some of the largest and longest-living organisms on Earth.

The Current Biology study suggests that surviving drought may have been a powerful force shaping the evolution of trees. It challenges conventional ideas about what defines a tree.

Rather than viewing trees simply as plants with trunks and wood, the researchers argue that a defining feature may be their ability to add and replace water transport tissues throughout their lives. Becoming tree-like and growing taller to compete for sunlight, they argue, required solving a critical challenge—moving water through a massive organism.

Water became the central challenge
To grow tall, trees must move water upward from their roots to their trunks, branches and leaves. But as they grew larger, keeping more and more water moving became increasingly difficult, especially when water became scarce.

Xylem, the microscopic tubes that carry water through plants, can become blocked by air bubbles called embolisms. If those blockages spread, they can cut off water to the rest of the plant and kill it. As plants evolved larger and more extensive water-transport systems, they became more vulnerable to embolisms and hydraulic failure.

But tree-like plants, the researchers propose, started to compartmentalize these systems to limit the spread of damage.

The strategy is similar to a power grid with circuit breakers or a ship with watertight compartments: If one section fails, the entire system doesn't go down with it.

That led the researchers to a new conclusion: The evolution of trees may have been driven by the need to move more water through their increasingly taller bodies and survive hydraulic failure...