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One bad rainstorm away from disaster: Why proposed changes to forestry rules won’t solve the ‘slash’ problem

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29/06/2025

One bad rainstorm away from disaster: Why proposed changes to forestry rules won’t solve the ‘slash’ problem

The biggest environmental problems for commercial plantation forestry in New Zealand’s steep hill country are discharges of slash (woody debris left behind after logging) and sediment from clear-fell harvests.

During the past 15 years, there have been 15 convictions of forestry companies for slash and sediment discharges into rivers, on land and along the coastline.

Such discharges are meant to be controlled by the National Environmental Standards for Commercial Forestry, which set environmental rules for forestry activities such as logging roads and clear-fell harvesting. The standards are part of the Resource Management Act (RMA), which the government is reforming.

The government revised the standards’ slash-management rules in 2023 after Cyclone Gabrielle. But it is now consulting on a proposal to further amend the standards because of cost, uncertainty and compliance issues.

We believe the proposed changes fail to address the core reasons for slash and sediment discharges.

We recently analyzed five convictions of forestry companies under the RMA for illegal discharges. Based on this analysis, which has been accepted for publication in the New Zealand Journal of Forestry, we argue that the standards should set limits to the size and location of clear-felling areas on erosion-susceptible land.

Why the courts convicted five forestry companies

In the aftermath of destructive storms in the Gisborne district during June 2018, five forestry companies were convicted for breaches of the RMA for discharges of slash and sediment from their clear-fell harvesting operations. These discharges resulted from landslides and collapsed earthworks (including roads).

There has been a lot of criticism of forestry’s performance during these storms and subsequent events such as Cyclone Gabrielle. However, little attention has been given to why the courts decided to convict the forestry companies for breaches of the RMA.

The courts’ decisions clearly explain why the sediment and slash discharges happened, why the forestry companies were at fault, and what can be done to prevent these discharges in future on erosion-prone land.

New Zealand’s plantation forest land is ranked for its susceptibility to erosion using a four-color scale, from green (low) to red (very high). Because of the high erosion susceptibility, additional RMA permissions (consents) for earthworks and harvesting are required on red-ranked areas.

New Zealand-wide, only 7% of plantation forests are on red land. A further 17% are on orange (high susceptibility) land. But in the Gisborne district, 55% of commercial forests are on red land. This is why trying to manage erosion is such a problem in Gisborne’s forests.

Key findings from the forestry cases

In all five cases, the convicted companies had consents from the Gisborne District Council to build logging roads and clear-fell large areas covering hundreds or even thousands of hectares.

A significant part of the sediment and slash discharges originated from landslides that were primed to occur after the large-scale clear-fell harvests. But since the harvests were lawful, these landslides were not relevant to the decision to convict.

Instead, all convictions were for compliance failures where logging roads and log storage areas collapsed or slash was not properly disposed of, even though these only partly contributed to the collective sediment and slash discharges downstream.

The court concluded that:

Clear-fell harvesting on land highly susceptible to erosion required absolute compliance with resource consent conditions. Failures to correctly build roads or manage slash contributed to slash and sediment discharges downstream.
Even with absolute compliance, clear-felling on such land was still risky. This was because a significant portion of the discharges were due to the lawful activity of cutting down trees and removing them, leaving the land vulnerable to landslides and other erosion.

The second conclusion is critical. It means that even if forestry companies are fully compliant with the standards and consents, slash and sediment discharges can still happen after clear-felling. And if this happens, councils can require companies to clean up these discharges and prevent them from happening again.

This is not a hypothetical scenario. Recently, the Gisborne District Council successfully applied to the Environment Court for enforcement orders requiring clean-up of slash deposits and remediation of harvesting sites. If the forestry companies fail to comply, they can be held in contempt of court.

Regulations are not just red tape

This illustrates a major problem with the standards that applies to erosion-susceptible forest land everywhere in New Zealand, not just in the Gisborne district. Regulations are not just “red tape”. They provide certainty to businesses that as long as they are compliant, their activities should be free from legal prosecution and enforcement.

The courts’ decisions and council enforcement actions show that forestry companies can face considerable legal risk, even if compliant with regulatory requirements for earthworks and harvesting.

Clear-felled forests on erosion-prone land are one bad rainstorm away from disaster. But with well-planned, careful harvesting of small forest areas, this risk can be kept at a tolerable level.

However, the standards and the proposed amendments do not require small clear-fell areas on erosion-prone land. If this shortcoming is not fixed, communities and ecosystems will continue to bear the brunt of the discharges from large-scale clear-fell harvests.

To solve this problem, the standards must proactively limit the size and location of clear-felling areas on erosion-prone land. This will address the main cause of catastrophic slash and sediment discharges from forests, protecting communities and ecosystems. And it will enable forestry companies to plan their harvests with greater confidence that they will not be subject to legal action.

Provided by The Conversation

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Natural hazards don’t disappear when the storm ends or the earthquake stops—they evolve

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29/06/2025

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Natural hazards don’t disappear when the storm ends or the earthquake stops—they evolve

Hurricane Helene lasted only a few days in September 2024, but it altered the landscape of the Southeastern U.S. in profound ways that will affect the hazards local residents face far into the future.

Mudslides buried roads and reshaped river channels. Uprooted trees left soil on hillslopes exposed to the elements. Sediment that washed into rivers changed how water flows through the landscape, leaving some areas more prone to flooding and erosion.

Helene was a powerful reminder that natural hazards don’t disappear when the skies clear—they evolve.

These transformations are part of what scientists call cascading hazards. They occur when one natural event alters the landscape in ways that lead to future hazards. A landslide triggered by a storm might clog a river, leading to downstream flooding months or years later. A wildfire can alter the soil and vegetation, setting the stage for debris flows with the next rainstorm.

I study these disasters as a geomorphologist. In a new paper in the journal Science, I and a team of scientists from 18 universities and the U.S. Geological Survey explain why hazard models—used to help communities prepare for disasters—can’t just rely on the past. Instead, they need to be nimble enough to forecast how hazards evolve in real time.

The science behind cascading hazards

Cascading hazards aren’t random. They emerge from physical processes that operate continuously across the landscape—sediment movement, weathering, erosion. Together, the atmosphere, biosphere and Earth are constantly reshaping the conditions that cause natural disasters.

For instance, earthquakes fracture rock and shake loose soil. Even if landslides don’t occur during the quake itself, the ground may be weakened, leaving it primed for failure during later rainstorms.

That’s exactly what happened after the 2008 earthquake in Sichuan Province, China, which led to a surge in debris flows long after the initial seismic event.

Earth’s surface retains a “memory” of these events. Sediment disturbed in an earthquake, wildfire or severe storm will move downslope over years or even decades, reshaping the landscape as it goes.

The 1950 Assam earthquake in India is a striking example: It triggered thousands of landslides. The sediment from these landslides gradually moved through the river system, eventually causing flooding and changing river channels in Bangladesh some 20 years later.

An intensifying threat in a changing world

These risks present challenges for everything from emergency planning to home insurance. After repeated wildfire-mudslide combinations in California, some insurers pulled out of the state entirely, citing mounting risks and rising costs among the reasons.

Cascading hazards are not new, but their impact is intensifying.

Climate change is increasing the frequency and severity of wildfires, storms and extreme rainfall. At the same time, urban development continues to expand into steep, hazard-prone terrain, exposing more people and infrastructure to evolving risks.

The rising risk of interconnected climate disasters like these is overwhelming systems built for isolated events.

Yet climate change is only part of the equation. Earth processes—such as earthquakes and volcanic eruptions—also trigger cascading hazards, often with long-lasting effects.

Mount St. Helens is a powerful example: More than four decades after its eruption in 1980, the U.S. Army Corps of Engineers continues to manage ash and sediment from the eruption to keep it from filling river channels in ways that could increase the flood risk in downstream communities.

Rethinking risk and building resilience

Traditionally, insurance companies and disaster managers have estimated hazard risk by looking at past events.

But when the landscape has changed, the past may no longer be a reliable guide to the future. To address this, computer models based on the physics of how these events work are needed to help forecast hazard evolution in real time, much like weather models update with new atmospheric data.

Thanks to advances in Earth observation technology, such as satellite imagery, drone and lidar, which is similar to radar but uses light, scientists can now track how hillslopes, rivers and vegetation change after disasters. These observations can feed into geomorphic models that simulate how loosened sediment moves and where hazards are likely to emerge next.

Researchers are already coupling weather forecasts with post-wildfire debris flow models. Other models simulate how sediment pulses travel through river networks.

Cascading hazards reveal that Earth’s surface is not a passive backdrop, but an active, evolving system. Each event reshapes the stage for the next.

Understanding these connections is critical for building resilience so communities can withstand future storms, earthquakes and the problems created by debris flows. Better forecasts can inform building codes, guide infrastructure design and improve how risk is priced and managed. They can help communities anticipate long-term threats and adapt before the next disaster strikes.

Most importantly, they challenge everyone to think beyond the immediate aftermath of a disaster—and to recognize the slow, quiet transformations that build toward the next.

Journal information: Science

Provided by The Conversation

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How night lizards survived the asteroid that ended the dinosaurs

PALEONTOLOGY

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29/06/2025

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How night lizards survived the asteroid that ended the dinosaurs

Yale University ecologists reveal a lizard lineage that rode out the dinosaur-killing asteroid event with unexpected evolutionary survival traits. Night lizards (family Xantusiidae) survived the Cretaceous–Paleogene (K-Pg) mass extinction event 66 million years ago (formerly known as the K-T extinction) despite having small broods and occupying limited ranges, a departure from the theory of how other species are thought to have persisted in the aftermath of the event.

Before K-Pg, Earth was a warm, thriving planet with lush forests and diverse ecosystems both on land and in the oceans. Dinosaurs were widespread, diverse, and dominant. Marine reptiles patrolled the seas and pterosaurs soared through the skies. Future humans were still shrew-like, tree-dwelling creatures, part of a small but growing evolutionary experiment into placental mammals.

An asteroid more than six miles across, moving around 43,200 miles per hour, struck the Chicxulub region of Yucatán, Mexico, releasing an incomprehensible 10²³ joules of energy. For context, if every explosive that humans have ever made all detonated at once, it still wouldn’t come close to the energy released by the Chicxulub asteroid.

A 1,000-mile radius of forest was instantly incinerated by the extreme heat, as the impact gouged a crater more than 100 miles wide and 12 miles deep. Tsunamis, roughly the height of the Eiffel Tower, propagated outward, ravaging shorelines and sea floors across the globe, and rang Earth’s mantle like a bell, setting off what today would be city-leveling mega-earthquakes greater than magnitude 10.

And just when the worst seemed to be over, it got even worse. Debris ejected from the impact that had risen above Earth’s atmosphere began raining back down. Superheated upon reentry, it pelted the planet with a deadly shower of molten projectiles that started global fires.

Vast amounts of soot, dust, and aerosols were left lingering in the stratosphere, blocking sunlight and plunging the planet into an “impact winter” with plummeting global temperatures. Without photosynthesis, plant life began to die off, and food chains from the smallest ocean plankton to largest dinosaurs were obliterated. Acid rain, produced by vaporized sulfur-rich rocks, induced rapid changes in ocean chemistry, which led to the widespread extinction of plankton, ammonites, and many marine reptiles.

When it was over, 75% of species, the products of billions of years of evolution, were gone. It is a wonder that anything at all survived the event, but life did find a way.

In the study, “Night lizards survived the Cretaceous–Paleogene mass extinction near the asteroid impact,” published in Biology Letters, researchers combined phylogenetic tip-dating with ancestral-trait reconstruction to determine whether xantusiid lizards originated before the K-Pg boundary and to identify features that may have aided their survival.

Genetic data from 34 living night-lizard species, integrated with fossils ranging from the Early Cretaceous to Miocene strata across North America, Central America, and Cuba, anchored the analyses.

Genetic clocks traced Cricosaura typica, a Cuban species, to the earliest branch in the family tree, splitting off before its North and Central American cousins emerged. Species of Lepidophyma and Xantusia diversified much later, in parallel radiations about 12 million years ago, long after the asteroid had reshaped their ancestral landscape.

On California’s Channel Islands, the giant island night lizard evolved from a mainland lineage that dispersed west roughly 10 million years back, crossing temporary land bridges before becoming isolated.

Researchers found the 34 living night-lizard species descended from at least two ancient lineages that began roughly 92 million years ago, and survived the K-Pg boundary. Unlike survivors among birds or mammals, these lizards carried forward a life strategy with comparatively small litters.

Statistical reconstruction estimated that ancestral females produced about two offspring at a time, a figure bounded by the single-egg clutches of Cricosaura and the more prolific broods seen in the larger-bodied island species. Body size and fecundity still move in tandem across the lineage, suggesting that bigger litters evolved later, possibly in response to island habitats.

Authors contend that the persistence of night lizards through the Cretaceous–Paleogene extinction event unsettles assumptions about which traits shield lineages from annihilation. Survival did not depend on broad geographic ranges or large broods, qualities often credited in mammals and birds. Instead, night lizards appear to have crossed the extinction threshold while occupying narrow habitats and producing only one or two offspring per reproductive event.

Because of the intensity of K-Pg, there can be no direct fossil evidence that Cretaceous night lizards (or anything else) occupied the immediate impact region. Instead, the inference of proximity rests on reconstructed ancestral ranges in North and Central America and molecular dating placing their common ancestor in the Late Cretaceous. Together, this offers indirect evidence of a front row seat for the most devastating event in Earth’s history.

Insights from these lizards’ survival may refine how scientists project which species are likely to weather rapid environmental shifts, especially as the current, human-driven mass extinction accelerates.

Written for you by our author Justin Jackson, edited by Lisa Lock , and fact-checked and reviewed by Robert Egan —this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You’ll get an ad-free account as a thank-you.

More information: Chase D. Brownstein et al, Night lizards survived the Cretaceous–Palaeogene mass extinction near the asteroid impact, Biology Letters (2025). DOI: 10.1098/rsbl.2025.0157

Journal information: Biology Letters

Ancient squids dominated the ocean 100 million years ago, fossil discovery technique reveals

PALEONTOLOGY

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27/06/2025

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Ancient squids dominated the ocean 100 million years ago, fossil discovery technique reveals

Squids first appeared about 100 million years ago and quickly rose to become dominant predators in the ancient oceans, according to a study published in the journal Science.

A team of researchers from Hokkaido University developed an advanced fossil discovery technique that completely digitizes rocks with all embedded fossils in complete 3D form. It allowed them to identify one thousand fossilized cephalopod beaks hidden inside Late Cretaceous rocks from Japan. Among these small and fragile beaks were 263 squid specimens, including about 40 different species that had never been seen before.

Squids are rarely preserved as fossils because they don’t have hard shells. Their origin and early evolution are the biggest questions in the 500 million-year history of cephalopods, which have been model animals for long-term evolution. Squid beaks, hard mouthparts that have a high fossilization potential, are therefore important clues for studying how squids evolved.

One of the study’s most striking discoveries was how common squids were in ancient oceans. The team found that squid fossils far outnumbered those of ammonites and bony fishes. Ammonites are extinct shelled relatives of squids and have been considered among the most successful swimmers of the Mesozoic era.

“In both number and size, these ancient squids clearly prevailed the seas,” said Dr. Shin Ikegami of the Department of Earth and Planetary Sciences at Hokkaido University, the study’s first author.

“Their body sizes were as large as fish and even bigger than the ammonites we found alongside them. This shows us that squids were thriving as the most abundant swimmers in the ancient ocean.”

Ancient squids dominated the ocean 100 million years ago — An example of grinding tomography images. Credit: Ikegami et al., *Science*, June 26, 2025

The research also revealed that the two main groups of modern squids, Myopsida, which live near the shore, and Oegopsida, found in the open sea, were already present around 100 million years ago.

Until now, scientists believed that squids only began to flourish after the mass extinction event that ended the age of dinosaurs about 65 million years ago. The new study shows that squids had already originated and explosively diversified long before then.

“These findings change everything we thought we knew about marine ecosystems in the past,” said Associate Professor Yasuhiro Iba of the Department of Earth and Planetary Sciences at Hokkaido University, who led the study.

“Squids were probably the pioneers of fast and intelligent swimmers that dominate the modern ocean.”

More information: Shin Ikegami et al, Origin and radiation of squids revealed by digital fossil-mining, Science (2025). DOI: 10.1126/science.adu6248. www.science.org/doi/10.1126/science.adu6248

Journal information: Science

Provided by Hokkaido University

Fossil fungi trapped in amber reveal ancient origin of parasitic zombie-ants

PALEONTOLOGY

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27/06/2025

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Fossil fungi trapped in amber reveal ancient origin of parasitic zombie-ants

Chinese Academy of Sciences researchers report that fossilized entomopathogenic fungi from mid-Cretaceous amber reveal some of the oldest direct evidence of parasitic relationships between fungi and insects, suggesting that Ophiocordyceps fungi originated approximately 133 million years ago and underwent early host shifts that shaped their evolution.

Entomopathogenic fungi have evolved extraordinary ways to turn insects into unwitting accomplices in their own demise. Among the most famous are the “zombie ant fungi,” Ophiocordyceps unilateralis, which infect carpenter ants in tropical rainforests. After infecting the ant’s body, the fungus hijacks the host’s nervous system, compelling it to abandon the safety of its nest.

The ant becomes a macabre six-legged marionette, compelled to climb a plant to a height above the colony, where it clamps its jaws onto a leaf. Locked into a final death grip, the ant dies while the fungus slowly consumes its tissues. After a while, a spore-producing stalk erupts grotesquely from the back of the ant’s head, scattering infectious spores down onto the forest floor to restart the cycle with fresh victims.

But ants are far from the only victims of fungal mind control. In grasslands and fields, entomopathogenic fungi like Entomophthora grylli invade grasshoppers and crickets, orchestrating a similar, chilling scenario known as “summit disease.” As infection progresses, the insect abandons its usual behavior, ascending to the tops of grasses or tall weeds. There, it perches in a characteristic posture, often gripping the plant with its legs stretched outward.

As the fungus bursts through the exoskeleton, it releases clouds of spores that drift down onto the unsuspecting insects below. In some cases, related fungi have been observed driving their hosts to wander aimlessly before ultimately walking into streams or ponds, where they drown, ensuring the fungus can grow in the moist environment that best suits it.

Flies, too, fall prey to fungal manipulation. Entomophthora muscae infects common houseflies, also driving them to climb to high spots, upper corners of windows or walls, just before death. There, the fly extends its proboscis to glue itself in place, creating the perfect platform for the fungus to erupt through the soft parts of the body. From the cadaver, spore-laden filaments radiate outward, releasing infectious particles into the air to settle onto new hosts.

Even spiders can be commandeered. Some Ophiocordyceps species compel infected spiders to attach themselves to leaves or twigs before succumbing, ensuring the fungus can safely grow a fruiting body that rains spores into the surrounding habitat.

These remarkable strategies highlight the astonishing evolutionary tactics of parasitic fungi. By reprogramming their hosts’ instincts for climbing, gripping, and walking, they orchestrate ideal conditions for their own reproduction. What appears to be mindless self-destruction by the insect is, in reality, the well-executed plan of a fungus perfectly adapted to exploit its host’s body and behavior.

Direct fossil evidence of these relationships has remained scarce, largely because soft fungal tissues rarely fossilize and their pathogenic nature can be difficult to discern in ancient specimens. Previous research has documented only a handful of tentative fossil records, and estimates of the evolutionary origins of Ophiocordyceps fungi relied on limited calibration points and indirect evidence.

In the study, “Cretaceous entomopathogenic fungi illuminate the early evolution of insect–fungal associations,” published in Proceedings of the Royal Society B: Biological Sciences, researchers described two newly identified fungal species preserved in approximately 99-million-year-old Kachin amber.

One of the two fossil fungi described in the study, Paleoophiocordyceps gerontoformicae, occurred in association with an infected ant pupa encased in mid-Cretaceous Kachin amber dated to about 99 million years ago. Researchers assigned the ant host to the extinct genus Gerontoformica, belonging to the subfamily Sphecomyrminae.

Infection likely began inside the nest, since ant larvae do not leave the nest. Workers may have transported fungal spores into the nest and removed the pupa to maintain colony hygiene just as modern ant colonies do. The fossil pupa possibly represents an early instance of such behavior, with disposal outside the nest preceding resin entombment.

Morphological features of P. gerontoformicae matched characteristics seen in extant myrmecophilous Ophiocordyceps species. A combination of laterally attached ascoma and asexual traits similar to the Hirsutella clade suggested a position near the base of both myrmecophilous hirsutelloid and O. sphecocephala lineages.

Results indicated that Ophiocordyceps likely emerged during the Early Cretaceous, about 133.25 million years ago, earlier than previously proposed estimates of ~100 million years. Ancestral state reconstructions suggest that the genus initially parasitized beetles before undergoing host shifts to Lepidoptera and Hymenoptera during the Cretaceous. Researchers inferred that these transitions coincided with the diversification of moths and ants, which offered new ecological opportunities for fungal specialization.

The authors concluded that the fossils not only document some of the oldest evidence of insect-pathogenic fungi but also support the view that Ophiocordyceps diversified in tandem with its insect hosts.

Written for you by our author Justin Jackson, edited by Lisa Lock , and fact-checked and reviewed by Robert Egan —this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You’ll get an ad-free account as a thank-you.

More information: Yuhui Zhuang et al, Cretaceous entomopathogenic fungi illuminate the early evolution of insect – fungal associations, Proceedings of the Royal Society B: Biological Sciences (2025). DOI: 10.1098/rspb.2025.0407

Journal information: Proceedings of the Royal Society B

Will asteroid 2024 YR4 hit the moon?

ASTRONOMY

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27/06/2025

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Asteroid 2024 YR4 made headlines earlier this year when its probability of impacting Earth in 2032 rose as high as 3%. While an Earth impact has now been ruled out, the asteroid’s story continues.

The final glimpse of the asteroid as it faded out of view of humankind’s most powerful telescopes left it with a 4% chance of colliding with the moon on 22 December 2032.

The likelihood of a lunar impact will now remain stable until the asteroid returns to view in mid-2028. In this FAQ, find out why we are left with this lingering uncertainty and how ESA’s planned NEOMIR space telescope will help us avoid similar situations in the future.

What is asteroid 2024 YR4?

Asteroid 2024 YR4 was discovered on 27 December 2024 at the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in Río Hurtado, Chile.

Shortly after its discovery, automated asteroid warning systems determined that the object had a small chance of potentially impacting Earth on 22 December 2032.

The asteroid is between 53 and 67 meters in diameter. An asteroid of this size impacts Earth on average only once every few thousand years and would cause severe damage to a city or region.

Follow-up observations saw the chance of impact rise to around 3%. As a result, the asteroid shot to the top of ESA’s asteroid risk list and captured global attention as it became the first asteroid to trigger a coordinated international planetary defense response.

https://youtube.com/watch?v=-tNE63GAU6s%3Fcolor%3Dwhite

Additional observations made over the next few months, including those made using the James Webb Space Telescope, allowed astronomers to more accurately measure the asteroid’s orbit around the sun.

By March 2025, they had enough information to rule out an Earth impact in 2032.

Why did we not detect 2024 YR4 sooner?

2024 YR4 was first discovered two days after it had already passed its closest point to Earth. It was not detected sooner because it approached Earth from the day side of the planet, from a region of the sky hidden by the bright light of the sun.

This region of the sky is hidden from the view of ground-based optical telescopes and is a blind spot for asteroid warning systems.

The significance of this blind spot was made clear on 15 February 2013, when the Chelyabinsk meteor, a 20-meter, 13,000-ton asteroid, struck the atmosphere over the Ural Mountains in Russia during the middle of the day. The resulting blast damaged thousands of buildings, and roughly 1,500 people were injured by shards of glass.

Could we have detected 2024 YR4 sooner?

ESA’s Near-Earth Object Mission in the InfraRed (NEOMIR) satellite, planned for launch in the early 2030s, will cover this important blind spot.

NEOMIR will be equipped with an infrared telescope and positioned at the first sun-Earth Lagrange Point. By relying on infrared light, rather than visible light, NEOMIR can spot asteroids in a region of the sky much closer to the sun. It will repeatedly scan this region for the thermal signatures of asteroids approaching Earth that are at least 20 meters across—like 2024 YR4 and the Chelyabinsk meteor.

“We looked into how NEOMIR would have performed in this situation, and the simulations surprised even us,” says Richard Moissl, Head of ESA’s Planetary Defense Office.

“NEOMIR would have detected asteroid 2024 YR4 about a month earlier than ground-based telescopes did. This would have given astronomers more time to study the asteroid’s trajectory and allowed them to much sooner rule out any chance of Earth impact in 2032.”

“As an infrared telescope, like Webb, NEOMIR would have also immediately given us a much better estimate of the asteroid’s size, which is very important for assessing the significance of the hazard.”

Will asteroid 2024 YR4 impact the moon?

By March 2025, astronomers had ruled out an Earth impact in 2032. However, the final observations of the asteroid failed to rule out another intriguing possibility: a lunar impact.

The probability that asteroid 2024 YR4 will strike the moon on 22 December 2032 is now approximately 4%, and this probability was still slowly rising as the asteroid faded out of view.

However, this means that there is a 96% chance that the asteroid will not impact the moon.

When will we know for sure?

We are left with an interesting situation: there is now a 60 m asteroid with a 4% chance of hitting the moon in 2032. As the asteroid is now too far away to study any further, this probability will remain unchanged until it returns into view in June 2028.

When it does return into view, new observations will be made and it will not take long for astronomers to confidently determine whether the asteroid will, or much more likely, will not, hit the moon on 22 December 2032.

What will happen if the asteroid hits the moon?

“A lunar impact remains unlikely, and no one knows what the exact effects would be,” says Richard Moissl.

“It is a very rare event for an asteroid this large to impact the moon—and it is rarer still that we know about it in advance. The impact would likely be visible from Earth, and so scientists will be very excited by the prospect of observing and analyzing it. I am sure that detailed computational simulations will be done over the next few years.”

“It would certainly leave a new crater on the surface. However, we wouldn’t be able to accurately predict in advance how much material would be thrown into space, or whether any would reach Earth.”

In the coming years, as humankind looks to establish a prolonged presence on the moon, monitoring space for objects that could strike Earth’s natural satellite will become increasingly important.

Small objects burn up in Earth’s atmosphere as meteors, but the moon lacks this shield. Objects just tens of centimeters in size could pose a significant hazard to astronauts and lunar infrastructure.

What else is ESA doing to improve Europe’s planetary defense capabilities?

The discovery of asteroid 2024 YR4 made it clear that time is of the essence when it comes to asteroid detection. In cases like that of 2024 YR4, the later an asteroid is detected, the less time is available for follow-up observations before it fades from view.

Decision makers need as much information as possible when considering potential mitigation strategies, such as deflection missions or evacuation plans: they do not want to be left with an uncertain but significant chance of Earth impact for multiple years.

By keeping watch for asteroids approaching Earth from the direction of the sun, ESA’s NEOMIR space telescope will fill an important blind spot in our current asteroid detection systems and significantly improve our preparedness for future hazards similar to 2024 YR4.

More information: Follow the links below to find out more about ESA’s other Planetary Defense activities, such as the Near-Earth Object Coordination Center (NEOCC); the Flyeye asteroid survey telescopes; the Hera mission, which will turn asteroid deflection into a well-understood and repeatable technique for planetary defense; and the Ramses mission to intercept and explore the infamous asteroid Apophis as it safely passes close to Earth in 2029.

Provided by European Space Agency

Cryovolcanism and resurfacing on Pluto’s largest moon, Charon

ASTRONOMY

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27/06/2025

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Cryovolcanism and resurfacing on Pluto’s largest moon, Charon

What processes during the formation of Pluto’s largest moon, Charon, potentially led to it having cryovolcanism, and even an internal ocean? This is what a recent study presented at the 56th Lunar and Planetary Science Conference (LPSC 2025) hopes to address as a team of researchers investigated the formation and evolution of Charon to ascertain whether it once possessed an internal ocean during its history and if this could have led to cryovolcanism based on images obtained by NASA’s New Horizons probe.

For the study, the researchers used a series of computer models to simulate the early conditions on Charon that could have resulted in creating an internal ocean and potentially cryovolcanism, resulting in the southern hemisphere, known as Vulcan Planitia, being resurfaced from cryovolcanism. It is currently hypothesized that Charon collided with Pluto and one goal of this work was to ascertain if Charon first formed before the collision or after.

While only a portion of Charon’s surface was briefly imaged by NASA’s New Horizons spacecraft in July 2015, this limited dataset has provided planetary scientists with intriguing insights into its formation and evolution. This includes kilometers-high scarps that run along the moon’s equator, with the southern hemisphere being more cratered than the northern hemisphere. In the end, the models estimated that Charon’s subsurface ocean likely formed between 370 million and 400 million years ago and fully froze between 2.12 billion years ago and 2.2 billion years ago.

The study notes, “Crucially, in no simulation across any parameter studied so far did the ocean fully freeze in a timeframe consistent with massive cryovolcanic eruptions before 4 Gyr ago. These results strongly suggest that if ocean freezing is the cause of the resurfacing of Vulcan Planitia at 4 Gyr ago, the details of the impact matter.”

Discovered in 1978, Charon is one of the most intriguing moons in the solar system due to being approximately half the diameter of Pluto, which is the largest known satellite relative to its parent body it’s orbiting. For context, Earth’s moon is approximately one-quarter the diameter of Earth. Several hypotheses regarding Charon’s formation and evolution have been proposed, with the most recent being both Pluto and Charon collided billions of years ago, were stuck together, and eventually came apart and formed the two planetary bodies we see today.

Given the enormous distance from Earth at just under 3.2 billion miles, traveling to the Pluto system takes many years, with NASA’s New Horizons taking more than 9.5 years to reach Pluto and Charon for its brief flyby in July 2015. This brief flyby provided scientists with enough data about Pluto and Charon that continues to be pored over today, with scientists continuing to learn more about this intriguing system and how both planetary bodies formed and evolved.

Both planetary bodies are part of the Kuiper Belt, which is a donut-shaped region of icy, rocky objects beyond the orbit of Neptune. While Pluto is the most well-known dwarf planet in the Kuiper Belt, other dwarf planets include Haumea, Makemake, and Eris.

While no follow-up missions to Pluto are currently being planned, several mission concepts are in development, ranging from an orbiter to a lander on Charon’s surface. If a subsurface ocean on Charon is confirmed, even a frozen one, this could challenge our understanding of how planetary bodies form and evolve, especially so far from the sun.

More information: Modeling Charon’s geochemical evolution: Implications for cryovolcanism. www.hou.usra.edu/meetings/lpsc2025/pdf/2267.pdf

Provided by Universe Today

How much water is left for nature? The search for the appropriate environmental flow

ENVIRONMENT

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26/06/2025

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How much water is left for nature? The search for the appropriate environmental flow

In many rivers, only a small amount of streamflow remains for nature after water is diverted for hydropower production. In light of climate change and biodiversity loss, this is having increasingly serious consequences. Researchers from WSL, UZH and Eawag have compiled an interdisciplinary overview and highlighted areas where knowledge gaps exist.

In many rivers, little streamflow remains because of anthropogenic water diversions for purposes such as energy production or agricultural irrigation. A legally required minimum flow, known as environmental flow, is intended to ensure the biological function of rivers. In the article “Restwasser. Die Suche nach der angemessenen Menge” (“Environmental flow. The search for the adequate amount,” German only) in the magazine Aqua & Gas, Tobias Wechsler from the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) describes why determining adequate environmental flows is so complex. “Environmental flow means a reduction in hydropower production, but a minimum subsistence level for aquatic ecology,” explains the hydrologist.

Since 1975, Switzerland’s constitution requires that “adequate environmental flows” be maintained after hydropower production. However, “when the environmental flow provisions were enshrined in the Water Protection Act in 1991, an approach prevailed that resulted in lower minimum environmental flows than recommended by ecological studies,” the authors write in their report.

Ecological relevance of environmental flow

Thirty years later, the ecology of our water bodies has not fared well. Aquatic organisms are overrepresented on Switzerland’s red lists of endangered species, with 65% of fish and cyclostomes and 47% of invertebrates listed. These groups provide a simplified way of assessing the ecological status of water bodies. Reduced water volumes can slow down streamflow velocity, promote algae growth, and cause greater fluctuations in water temperatures—conditions that are unsuitable for specialized species.

However, even organisms living in dry habitats in the riparian zone, such as on riverbanks, are affected, for example, species of dragonflies and shore plants, as well as birds such as the little ringed plover. “River organisms can cope with disturbances such as high or low water levels, but not with very small amounts of environmental flow or daily fluctuations, such as those caused by hydropower production,” says WSL ecologist Sabine Fink.

She is studying the ecological impacts of hydropeaking—the rapid fluctuations in streamflow caused by hydropower operations. Parts of the rivers almost dry up, while following sudden surges erode the stream bed and carve deep channels into it. Both have consequences for the organisms living in the riparian zones and on islands.

“In the Alpine rivers we have been observing over the last 10 years, that the species composition has changed and now corresponds to that found in classic dry habitats.”

It is becoming increasingly clear that climate change must also be taken into account. It affects stream flows and has a direct impact on water management, but also on biodiversity in rivers. At the same time, there is political will to expand hydropower generation.

“These changes raise the question of what constitutes an adequate amount of environmental flow,” emphasizes Wechsler. This is because the demands of nature and other water uses, such as for cooling water or irrigation, are also increasing.

“Environmental flow and streamflow fluctuations from individual power plants affect the survival of species and habitats in entire catchment areas,” says ecologist Fink, “which is why solutions are needed for entire river systems.”

Water rights should become more flexible

What could be the next steps? Wechsler sees these in particular in the design of water rights concessions. The right to use water, a public good, is currently granted for up to 80 years and allows little scope for adjustments during the term of the concession. “Adaptive management can help to respond better to changes such as climate change or hydropeaking—without losing planning security,” says Wechsler.

To better reconcile the various demands placed on rivers, transparent data is needed. Currently, there is no independent data on the impact of environmental flow requirements on hydropower production. However, “In the past, this influence has been overestimated,” write the authors of the study in Aqua & Gas. As scientists, ecologist Fink and hydrologist Wechsler aim to identify interrelationships and communicate them so that they can be incorporated into sustainable water resources management.

Limited flexibility in water concessions

For hydropower plants granted concessions before 1992, the environmental flow requirements (Art. 31–33 GSchG) only come into effect after new concessioning. This has led to long deadlines: as concessions were often granted for the maximum permissible period of 80 years, in some places almost a century can pass between the inclusion of adequate environmental flows in the constitution (1975), the entry into force of the water protection act “GSchG” (1992) and the actual implementation.

Provided by Swiss Federal Institute for Forest, Snow and Landscape Research

These Canadian rocks may be the oldest on Earth

PALEONTOLOGY

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26/06/2025

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These Canadian rocks may be the oldest on Earth

Scientists have identified what could be the oldest rocks on Earth from a rock formation in Canada.

The Nuvvuagittuq Greenstone Belt has long been known for its ancient rocks—plains of streaked gray stone on the eastern shore of Hudson Bay in Quebec. But researchers disagree on exactly how old they are.

Work from two decades ago suggested the rocks could be 4.3 billion years old, placing them in the earliest period of Earth’s history. But other scientists using a different dating method contested the finding, arguing that long-ago contaminants were skewing the rocks’ age and that they were actually slightly younger at 3.8 billion years old.

In the new study, researchers sampled a different section of rock from the belt and estimated its age using the previous two dating techniques—measuring how one radioactive element decays into another over time. The result: The rocks were about 4.16 billion years old.

The different methods “gave exactly the same age,” said study author Jonathan O’Neil with the University of Ottawa.

The new research was published Thursday in the journal Science.

Earth formed about 4.5 billion years ago from a collapsing cloud of dust and gas soon after the solar system existed. Primordial rocks often get melted and recycled by Earth’s moving tectonic plates, making them extremely rare on the surface today. Scientists have uncovered 4 billion-year-old rocks from another formation in Canada called the Acasta Gneiss Complex, but the Nuvvuagittuq rocks could be even older.

This photo provided by researcher Jonathan O’Neil shows the landscape at the Nuvvuagittuq Greenstone Belt in northeastern Canada. Credit: Jonathan O’Neil via AP
This photo provided by researcher Jonathan O’Neil shows the landscape at the Nuvvuagittuq Greenstone Belt in northeastern Canada. Credit: Jonathan O’Neil via AP
This photo provided by researcher Jonathan O’Neil shows the landscape at the Nuvvuagittuq Greenstone Belt in northeastern Canada. Credit: Jonathan O’Neil via AP
This photo provided by researcher Jonathan O’Neil shows the landscape at the Nuvvuagittuq Greenstone Belt in northeastern Canada. Credit: Jonathan O’Neil via AP

Studying rocks from Earth’s earliest history could give a glimpse into how the planet may have looked—how its roiling magma oceans gave way to tectonic plates—and even how life got started.

“To have a sample of what was going on on Earth way back then is really valuable,” said Mark Reagan with the University of Iowa, who studies volcanic rocks and lava and was not involved with the new study.

The rock formation is on tribal Inukjuak lands and the local Inuit community has temporarily restricted scientists from taking samples from the site due to damage from previous visits.

This photo provided by researcher Jonathan O’Neil shows a closeup of a rock from Canada’s Nuvvuagittuq Greenstone Belt dated to about 4.16 billion years old. Credit: Jonathan O’Neil via AP
This photo provided by researcher Jonathan O’Neil shows an outcropping of about 4.16 billion year old rocks at the Nuvvuagittuq Greenstone Belt in northeastern Canada, with a knife to indicate scale. Credit: Jonathan O’Neil via AP
This photo provided by researcher Jonathan O’Neil shows a closeup of a rock from Canada’s Nuvvuagittuq Greenstone Belt dated to about 4.16 billion years old. Credit: Jonathan O’Neil via AP
This photo provided by researcher Jonathan O’Neil shows an outcropping of about 4.16 billion year old rocks at the Nuvvuagittuq Greenstone Belt in northeastern Canada, with a knife to indicate scale. Credit: Jonathan O’Neil via AP

After some geologists visited the site, large chunks of rock were missing and the community noticed pieces for sale online, said Tommy Palliser, who manages the land with the Pituvik Landholding Corp. The Inuit community wants to work with scientists to set up a provincial park that would protect the land while allowing researchers to study it.

“There’s a lot of interest for these rocks, which we understand,” said Palliser, a member of the community. “We just don’t want any more damage.”

More information: C. Sole et al, Evidence for Hadean mafic intrusions in the Nuvvuagittuq Greenstone Belt, Canada, Science (2025). DOI: 10.1126/science.ads8461. www.science.org/doi/10.1126/science.ads8461

Journal information: Science

A new look at Colorado’s Dinosaur Ridge reveals what may be the largest known dinosaur mating dance arena

PALEONTOLOGY

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25/06/2025

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A new look at Colorado’s Dinosaur Ridge reveals what may be the largest known dinosaur mating dance arena

A team of paleontologists and researchers affiliated with several institutions in the U.S. has discovered what may be the largest known dinosaur mating dance arena ever found. For their study, published in the journal Cretaceous Research, the group used drone imagery to gain a new perspective on Colorado’s famous Dinosaur Ridge.

Dinosaur Ridge has been yielding dinosaur bones since the late 1800s. For this study, the research team got a new look at a part of the area at the base of the ridge that was once a tidal flat—one that was flooded periodically. Prior research had shown that there were a few dinosaur “lekking” spots, or leks, in the area.

Such spots, the researchers note, are similar to those still used by birds. They are places where males perform dances for females in hopes of winning a mate and in so doing tend to leave behind telltale footprints or scrape marks. To gain a better perspective, the researchers studied drone imagery of the area captured by the U.S. Geological Survey in 2019 and again in 2024.

Scientists find what may be the largest known dinosaur mating dance arena — Bedding plane surfaces at Dinosaur Ridge. (A) Main track site denoted by red arrow, surface 2b and 2h denoted by yellow arrows. (B–C) Orthomosaic and DSM of surface 2b with (D) radially arranged root traces preserved on the surface. (E) Field photograph of surface. Credit: *Cretaceous Research* (2025). DOI: 10.1016/j.cretres.2025.106176

In studying the images, the researchers found evidence of multiple dinosaur lekking spots, suggesting the whole site was once a single large lekking spot. The images also allowed the researchers to get a better view of the spots themselves—people, including scientists, are banned from walking in the area, lest they destroy historical evidence.

In their study, the research team found evidence of two distinct types of marks—bowl-like and long and thin. Such differences could speak to various behaviors, such as display and nest building. They also noted that prior digging at some of the dancing spots had revealed marks in different strata, suggesting a given site was used by different dinosaurs at different times. Different marks, they noted, also showed different dancing styles, such as dragging a claw.

The team also compared the lekking spots with others that have been identified in other sites in Colorado and Alberta, Canada, and found them to look much the same, adding more evidence of Colorado Ridge as the site of the largest dinosaur lek found to date.

Written for you by our author Bob Yirka, edited by Lisa Lock , and fact-checked and reviewed by Robert Egan —this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You’ll get an ad-free account as a thank-you.

More information: Rogers C.C. Buntin et al, A new theropod dinosaur lek in the Cretaceous Dakota Sandstone (Dinosaur Ridge, Colorado, USA), Cretaceous Research (2025). DOI: 10.1016/j.cretres.2025.106176

Journal information: Cretaceous Research