A giant star is changing before our eyes and astronomers are watching in real time

Astronomers discover a star changing on a human time scale.

Jacco Van Loon

Keiichi Ohnaka

Feb 6, 2026

By Jacco Van Loon and Keiichi Ohnaka

February 6, 2026

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Photo credit: SALT – The red supergiant with its suspected smaller, hotter twin living alongside it.

For decades, astronomers have been watching WOH G64, an enormous heavyweight star in the Large Magellanic Cloud, a galaxy visible with the naked eye from the Southern Hemisphere. This star is more than 1,500 times larger than the Sun and emitting over 100,000 times more energy. For a long time, red supergiant WOH G64 looked like a star steadily reaching the end of its life, shedding material and swelling in size as it began to run out of fuel.

Astronomers didn’t think its final demise would happen anytime soon, because no-one has ever seen a known red supergiant die. But in recent years astronomers – including our team working with the Southern African Large Telescope (SALT) – discovered that this star has started to change, growing dimmer than before and seemingly warmer. This has surprised scientists and suggests the star’s final stages of life may be more complicated, and perhaps unfold faster, than once thought.

Massive stars, more than about eight times the mass of the Sun, produce so much energy, which we see as light, that they run out of fuel within millions of years, instead of the billions of years of the Sun’s lifespan.

Most massive stars become gigantic, cool stars in the final million years or so of their life – so-called red supergiants. All red supergiants blow gaseous winds, losing weight as they do so. Some do this so strongly that the star becomes enveloped in a shroud of the ejected material containing gas and solid particles like tiny sand grains – called dust in astronomy. This makes them look dim in visual light, but very bright in the infrared where the dust shines.

In the 1960s Swedish astronomers Westerlund, Olander and Hedin discovered number 64 in their catalogue of red stars. They thought nothing of it, as it looked like an unremarkable red giant star, something the Sun and most other stars will become later in life. But when in the 1980s Nasa, the UK and The Netherlands launched the InfraRed Astronomical Satellite into space, astronomers Elias, Frogel and Schwering discovered that WOH G64 is the most luminous, coolest and dustiest red supergiant in the entire Large Magellanic Cloud, which harbours over a thousand red supergiants. More observations over the following decades showed the strong, steady modulations of the brightness expected of a pulsating star of that kind.

Then, in 2024, our team (both authors of this article and our collaborators in Germany and the US) succeeded in taking a close-up image of WOH G64 using the European Southern Observatory’s telescopes and revealed a fresh cloud of dust close to the star. It was the sharpest picture of a star in another galaxy ever taken (comparable to being able to spot an astronaut walk on the Moon from Earth). We discovered that in the last decade, unexpectedly, the star had started to eject much more dust than before. At that time, we did not have an idea about why and how.

It turns out, WOH G64 had also become dimmer, possibly because of the dust cloud it had ejected, and started to pulsate less and a little more quickly, suggesting it had shrunk. At the same time, the star seemed to look a lot warmer, leading some to believe it might have entered a new stage of its life – a so-called yellow hypergiant on its final path to doom.

All these phenomena are happening on a human time scale, which is usually not the case when we observe stars. This makes WOH G64 even more special. Is this star offering us an opportunity not to be missed to witness the final death throes of massive stars?

Now, as we start 2026, we have announced that observations we have obtained using the Southern African Large Telescope give us some clues about what is going on with WOH G64. The SALT observations show the overwhelming presence of ions in the vicinity of the star, which means that the gas is heated up to high temperatures by what must be a much hotter star. This should not have surprised anyone as the hot gas had been spotted in the 1980s and ever since. But we also found the imprint of molecules, implying cool gas (because molecules break up at high temperatures) likely in the atmosphere of the red supergiant. It did not appear to have changed into a yellow hypergiant, at least not yet.

For a long time, astronomers have suspected that the red supergiant has a smaller, hotter twin living alongside it, but they have somehow been reluctant to claim this in publications. And now it looks to be the elephant in the room. One way of making sense of our observations is that this hotter star, looking blue in contrast to its bigger, cooler, red sibling, heats gas it might have captured from the red supergiant’s wind. Now that the red supergiant has faded, the presence of the heated gas has just become more conspicuous.

If the orbit of the blue star is not a circle but quite elongated (Earth’s orbit around the Sun only slightly deviates from a circle), the distance between the blue star and the red supergiant varies. It may have got closer in recent years, and its gravity might have caused the atmosphere of the red supergiant to stretch out. This would make it more transparent overall, allowing us to see the warmer interior, but with cool, dark molecular patches left in places. That would also have made it easier for dust to form further out in its wind.

If that is true, then once the blue star starts to recede again on its orbit, WOH G64 might regain its former red supergiant glory. On the other hand, if it did throw off its coat entirely, then the molecules would disappear, and with it, the dust, and we would gain a clean view of the star. Then again, WOH G64 might do something else unexpected. It certainly teaches astronomers to be humble.

This article originally appeared on The Conversation. You can read it here.

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Photo credit: Jake C/Wikimedia Commons, CC BY-SA – Acid mine waste turns rocks orange along Shamokin Creek in Pennsylvania.

Environment, Science

America’s next big critical minerals source could be coal mine pollution – if we can agree on who owns it

Mine waste could power clean energy.

Good Partner

4/27/2026

Hélène Nguemgaing

Alan Collins

Across Appalachia, rust-colored water seeps from abandoned coal mines, staining rocks orange and coating stream beds with metals. These acidic discharges, known as acid mine drainage, are among the region’s most persistent environmental problems. They disrupt aquatic life, corrode pipes and can contaminate drinking water for decades.

However, hidden in that orange drainage are valuable metals known as rare earth elements that are vital for many technologies the U.S. relies on, including smartphones, wind turbines and military jets. In fact, studies have found that the concentrations of rare earths in acid mine waste can be comparable to the amount in ores mined to extract rare earths.

Scientists estimate that more than 13,700 miles (22,000 kilometers) of U.S. streams, predominantly in Pennsylvania and West Virginia, are contaminated with acid mine discharge.

We and our colleagues at West Virginia University have been working on ways to turn the acid waste in those bright orange creeks into a reliable domestic source for rare earths while also cleaning the water.

Experiments show extraction can work. If states can also sort out who owns that mine waste, the environmental cost of mining might help power a clean energy future.

Rare earths face a supply chain risk

Rare earth elements are a group of 17 metals, also classified as critical minerals, that are considered vital to the nation’s economy or security.

Despite their name, rare earth elements are not all that rare. They occur in many places around the planet, but in small quantities mixed with other minerals, which makes them costly and complex to separate and refine.

MP Materials’ Mountain Pass Rare Earth Mine and Processing Facility, in California near the Nevada border, is one of the few rare earth mines in the U.S. Tmy350/Wikimedia Commons, CC BY-SA

China controls about 70% of global rare earth production and nearly all refining capacity. This near monopoly gives the Chinese government the power to influence prices, export policies and access to rare earth elements. China has used that power in trade disputes as recently as 2025.

The United States, which currently imports about 80% of the rare earth elements it uses, sees China’s control over these critical minerals as a risk and has made locating domestic sources a national priority.

The U.S. Geological Survey has been mapping locations for potential rare earth mining, shown in pink. But it takes years to explore a locations and then get a mine up and running. USGS

Although the U.S. Geological Survey has been mapping potential locations for extracting rare earth elements, getting from exploration to production takes years. That’s why unconventional sources, like extracting rare earth elements from acid mine waste, are drawing interest.

Turning a mine waste problem into a solution

Acid mine drainage forms when sulfide minerals, such as pyrite, are exposed to air during mining. This creates sulfuric acid, which then dissolves heavy metals such as copper, lead and mercury from surrounding rock. The metals end up in groundwater and creeks, where iron in the mix gives the water an orange color.

Expensive treatment systems can neutralize the acid, with the dissolved metals settling into an orange sludge in treatment ponds.

For decades, that sludge was treated as hazardous waste and hauled to landfills. But scientists at West Virginia University and the National Energy Technology Laboratory have found that it contains concentrations of rare earth elements comparable to those found in mined ores. These elements are also easier to extract from acid mine waste because the acidic water has already released them from the surrounding rock.

Acid mine drainage flowing into Decker’s Creek in Morgantown, West Virginia, in 2024. Helene Nguemgaing

Experiments have shown how the metals can be extracted: Researchers collected sludge, separated out rare earth elements using water-safe chemistry, and then returned the cleaner water to nearby streams.

It is like mining without digging, turning something harmful into a useful resource. If scaled up, this process could lower cleanup costs, create local jobs and strengthen America’s supply of materials needed for renewable energy and high-tech manufacturing.

But there’s a problem: Who owns the recovered minerals?

The ownership question

Traditional mining law covers minerals underground, not those extracted from water naturally running off abandoned mine sites.

Nonprofit watershed groups that treat mine waste to clean up the water often receive public funding meant solely for environmental cleanup. If these groups start selling recovered rare earth elements, they could generate revenue for more stream cleanup projects, but they might also risk violating grant terms or nonprofit rules.

To better understand the policy challenges, we surveyed mine water treatment operators across Pennsylvania and West Virginia. The majority of treatment systems were under landowner agreements in which the operators had no permanent property rights. Most operators said “ownership uncertainty” was one of the biggest barriers to investment in the recovery of rare earth elements, projects that can cost millions of dollars.

Not surprisingly, water treatment operators who owned the land where treatment was taking place were much more likely to be interested in rare earth element extraction.

Map of acid mine drainage sites in West Virginia. Created by Helene Nguemgaing, based on data from West Virginia Department of Environmental Protection, West Virginia Office of GIS Coordination, and U.S. Geological Survey

West Virginia took steps in 2022 to boost rare earth recovery, innovation and cleanup of acid mine drainage. A new law gives ownership of recovered rare earth elements to whoever extracts them. So far, the law has not been applied to large-scale projects.

Across the border, Pennsylvania’s Environmental Good Samaritan Act protects volunteers who treat mine water from liability but says nothing about ownership.

Map of acid mine drainage sites in Pennsylvania. Created by Helene Nguemgaing, based on data from Pennsylvania Spatial Data Access

This difference matters. Clear rules like West Virginia’s provide greater certainty, while the lack of guidance in Pennsylvania can leave companies and nonprofits hesitant about undertaking expensive recovery projects. Among the treatment operators we surveyed, interest in rare earth element extraction was twice as high in West Virginia than in Pennsylvania.

The economics of waste to value

Recovering rare earth elements from mine water won’t replace conventional mining. The quantities available at drainage sites are far smaller than those produced by large mines, even though the concentration can be just as high, and the technology to extract them from mine waste is still developing.

Still, the use of mine waste offers a promising way to supplement the supply of rare earth elements with a domestic source and help offset environmental costs while cleaning up polluted streams.

Early studies suggest that recovering rare earth elements using technologies being developed today could be profitable, particularly when the projects also recover additional critical materials, such as cobalt and manganese, which are used in industrial processes and batteries. Extraction methods are improving, too, making the process safer, cleaner and cheaper.

Government incentives, research funding and public-private partnerships could speed this progress, much as subsidies support fossil fuel extraction and have helped solar and wind power scale up in providing electricity.

Treating acid mine drainage and extracting its valuable rare earth elements offers a way to transform pollution into prosperity. Creating policies that clarify ownership, investing in research and supporting responsible recovery could ensure that Appalachian communities benefit from this new chapter, one in which cleanup and clean energy advance together.

This article originally appeared on The Conversation. You can read it here.

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Photo credit: Canva – A group of people hiking in the mountains.

Exploration, Science

Humans nearly vanished 800,000 years ago, revealing a quiet truth: most family lines disappear

Your lineage is one of the few that never broke.

Mark Wales

4/24/2026

There was a moment in human history when our entire existence may have desperately clung to a thousand or so people. A DNA-based study found that between 800,000 and 900,000 years ago, our ancestors experienced a severe population crash.

This wasn’t humans dealing with a giant meteor like the one that wiped out the dinosaurs. It was a much slower stretch during which humanity teetered on the brink of disappearing completely. This bottleneck in the human gene pool, comprising roughly 1,280 breeding individuals, lasted about 117,000 years.

Removing representation of a human population group.
Photo credit: Canva

Human population levels plummet

According to Scientific American, the study analyzed modern human genomes to piece together what the early human population looked like. By constructing a complex family tree of genes from present-day humans, researchers were able to identify important evolutionary events.

During the Early-Middle Pleistocene, a period within the Ice Age, humans faced severe weather and intense glacial cycles. Most human ancestors may have died out, clearing the path for a new human species to take their place.

Focusing on Africa, the study showed that 813,000 years ago, human populations began to recover and grow again. With an estimated two-thirds of genetic diversity potentially lost, traits like brain size appear to have been among the important features that survived. “It represents a key period of time during the evolution of humans,” population geneticist and study co-author Ziqian Hao said. “So there are many important questions to be answered.”

DNA genome sequences.
Photo credit: Canva

Understanding evolution and ancestry

What we know about evolution reveals a different story than a simple, continuous line of human improvement. Over time, genetic lines disappear—not dramatically all at once. It’s a slow and steady change, generation after generation.

Human existence isn’t inevitable. Species strength or technical advancement doesn’t guarantee the future or explain our past. It’s contingent on narrow, accidental circumstances. A 2021 study showed that human evolution is better seen as a continuous flow of incremental fragments over time. Categorizing people into races and groups oversimplifies human history.

A diverse group of wooden figures.
Photo credit: Canva

What does the bottleneck study say about us?

The study reveals humanity didn’t simply decline; it nearly collapsed. With over 98% of our genetic diversity erased, entire branches of the human family tree permanently ceased to exist.

It’s quite possible that if even a few more of those genetic lines had ended, human history could have vanished with them. Most branches of life don’t continue. What we witness today reflects biological persistence and countless moments that could have gone another way.

A 2024 study conducted five billion simulations, revealing that as a species’ population shrinks, its risk of extinction rises. Even stable groups can quickly collapse if their numbers suddenly drop low enough.

A 2025 study found that small populations erode genetic diversity. Isolation increases inbreeding and elevates the risk of extinction. Once a lineage shrinks, recovery becomes vastly more challenging over time. Long-term survival is an exception, not the guiding rule.

Humanity likes to think of itself as the result of an incredibly unique progression. Perhaps studies like these suggest that we are actually what remains when everything else disappears. The reason any of us live today comes down to a small group of ancient outlasters: persevering individuals whose genetic lines are the building blocks of every human living today.

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Photo credit: Mickey Pullen/Smithsonian Environmental Research Center – A long-running experiment is testing tree mixes to develop the healthiest forests.

Environment, Science

Don’t just plant trees, plant forests to restore biodiversity for the future

Biodiversity makes planted forests stronger.

Good Partner

4/23/2026

John Parker

Justin Nowakowski

Around the world, people plan to plant more than 1 trillion trees this decade in an ambitious effort to slow climate change and reduce biodiversity loss. But if the past is prologue, many of those planted trees won’t survive. And if they do, they could end up as biological deserts that lack the richness and resilience of healthy forests.

It doesn’t have to be this way.

The United Nations declared 2021-2030 the Decade on Ecosystem Restoration to encourage efforts to repair degraded ecosystems. Tree planting has become a centerpiece of that effort, championed by initiatives such as the Bonn Challenge and the Trillion Trees Campaign.

However, many tree-planting commitments have a critical flaw: They rely too heavily on monoculture plantations – vast areas planted with just a single tree species.

A grove of commercially grown poplar trees, planted in lines with not much active beneath them. Mint Images via Getty Images

Monoculture plantations are generally one-way tickets to producing wood. But these high-yield plantations are high risk and can be surprisingly fragile. When drought, pests, or forest fires strike, entire monoculture plantations can fail at once. In one example, nearly 90% of 11 million saplings planted in Turkey died within three months due to drought and lack of maintenance.

Forests are more than just timber factories. They regulate water, store carbon, provide habitat for wildlife, cool the landscapes around them and even provide human health benefits.

Rather than gambling on a single species and hoping for the best, science now points to a smarter path that captures both ecological and economic benefits while minimizing risk: mixed-species plantings that mirror the biodiversity of a natural forest, ultimately creating forests that grow faster and are more resilient in the face of constant threats.

The long-running BiodiversiTREE study compares forest plots containing several tree species with single-species monocultures. The results, illustrated here, show that mixed-species plots, right, produce 80% larger trees compared with monocultures, left, resulting in denser canopy growth that creates cooler understory microclimates, leading to more abundant and species-rich communities of insects, spiders and birds. Sergio Ibarra/Smithsonian Environmental Research Center

We are community and landscape ecologists at the Smithsonian Environmental Research Center. Since 2013, we and our colleagues have been rigorously testing this idea in a large, ecosystem-scale experiment called BiodiversiTREE. The verdict is striking: Trees in mixed forests don’t just survive – they outgrow their monoculture counterparts and support dramatically more biodiversity.

Trees with diverse neighbors grow larger

Thirteen years ago, we teamed up with volunteers to plant nearly 18,000 tree seedlings on 60 acres of fallow fields on the Smithsonian Environmental Research Center campus near the Chesapeake Bay.

We didn’t plant just a single species. We planted 16 different native species from all walks of tree-life. Some species were fast-growing timber species, some were mid-story species, and some were slow-growing species that might not reach full size for a century or more.

Some plots we planted with just a single species – homogenous rows of the same species over and over again. But others were planted with random allotments of four and 12 species, reflecting the middle and upper ends of tree diversity in similar-sized areas of our local forests.

We asked a simple question: What would happen if we tried to mirror nature and plant a mixture of species instead of a monoculture?

A drone image shows some of the BiodiversiTREE plots, including monocultures, outlined in white, and mixture plantings, outlined in green. Mickey Pullen/Smithsonian Environmental Research Center

The differences over a decade later are striking.

The monoculture plots – those that survived – resemble traditional plantation forestry that historically has dominated rural lands in the Southeast and Pacific Northwest in the U.S. They contain rows of tall, narrow trees with sparse canopies and little life below.

The mixed-species plots, by contrast, are layered, complex and dynamic, with foliage filling the canopy and a diversity of plants and animals thriving underneath.

These visual contrasts reflect real ecological gains. Trees grown in mixtures, including important timber species like poplar and red oak, are up to 80% larger than the same species when grown alone. Mixed plots supported fewer leaf pathogens, more abundant caterpillar communities that provide food for birds, and increased phytochemical diversity in their leaves. We hypothesize that these leaf chemicals, some of which deter animals from eating them, reduced browsing damage from hungry deer, ultimately leading to higher tree growth in the mixed plots.

Plots with several tree species also had much fuller, denser leaf canopies, leading to cooler, shadier conditions that help understory plants flourish and support up to 50% more insects, spiders and birds.

The fuller canopy of 12-species forest plots like the one above supports more insects and birds than the monoculture plots. John Parker/Smithsonian Environmental Research Center

A sycamore monoculture plot at the BiodiversiTREE project provides little canopy cover. John Parker/Smithsonian Environmental Research Center

This pattern isn’t unique to our site. The BiodiversiTREE project is part of TreeDivNet, a global network of large-scale experiments spanning more than 1.2 million trees and hundreds of species. Across continents and climates, the results are consistent: Forests with a mix of species tend to grow larger, store more carbon and better withstand stress from drought, pests and disease.

So why are monocultures still common?

Despite decades of evidence, mixed-species plantings remain relatively rare in practice. Most commercial forestry operations still rely on monocultures, and these plantations are counted toward international planting campaigns aimed at slowing climate change and reversing biodiversity loss.

The reasons are generally practical: Mixed plantings can be more complex to design, more expensive to establish and harder to manage. Crucially, until recently, there has been limited evidence that they can match or exceed the economic returns of conventional plantations.

Technician Shelley Bennett uses high-resolution GPS to lay out plots for an experiment at the Smithsonian Environmental Research Center in Maryland. Regan Todd/Smithsonian Environmental Research Center

A new experiment at the Smithsonian Environmental Research Center called “Functional Forests” aims to bridge some of the gaps between science and practice. We’re developing intentionally designed combinations of trees to test whether specific mixtures of species can contribute ecological benefits while also providing timber and other services that humans need to support a thriving, sustainable economy.

Each of the 20 tree species in the Functional Forests project was chosen to provide one or more benefits, including timber, wildlife habitat, food for people, resistance to deer and climate resilience. But no single species provides all of these benefits.

Some of the nearly 200 plots will contain a single species, while others include carefully selected combinations of five species assembled based on the functions they provide. Some plots are protected from deer browsing, while others are left exposed.

The Functional Forests project includes trees with edible fruits like the pawpaw (Asimina triloba), one of 20 different tree species being planted there. Jamie Pullen/Smithsonian Environmental Research Center

By comparing these approaches, we can test how different planting strategies perform across a range of goals, from timber production to food production and from biodiversity to climate resilience.

Landowners and communities have different priorities, whether that’s producing wood, supporting wildlife or creating forests that can withstand a changing climate. The idea behind Functional Forests is to design plantings that can deliver these multiple benefits all at once, rather than optimizing for just one, essentially leveraging the positive effects of biodiversity to achieve real-world goals.

Planting 1 trillion trees wisely

The stakes are high. Restoration has become a major global investment, with hundreds of billions of dollars already being spent annually. Getting it wrong means wasted resources and missed opportunities to address some of the most pressing environmental challenges of our time.

If the world is going to plant a trillion trees, we believe it needs to do more than just put seedlings in the ground. It needs to rethink what a forest should be.

The goal isn’t just to grow trees. It’s to grow forests that last.

This article originally appeared on The Conversation. You can read it here.

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