Category: The Conversation – USA

Source: The Conversation – USA (2) – By Laura Toran, Professor of Environmental Geology, Temple University

In early January, a giant sinkhole formed at an intersection in the West Oak Lane neighborhood of North Philadelphia after a water main break. Just two weeks earlier, the city reopened a section of the Schuylkill River Trail in Center City that had been shut down for two months due to a sinkhole. Last summer, some residents of Point Breeze in South Philly also waited two months for a sinkhole on their block to be repaired.

Laura Toran is a hydrogeologist and professor emeritus of environmental geology at Temple University. The Conversation U.S. asked her what causes sinkholes, whether Philly is particularly prone to them, and why repairs can take so long.

What are sinkholes and how do they happen?

A sinkhole is a hole that opens up in the ground due to some change in the subsurface.

There are two categories of change that create sinkholes. One type is associated with carbonate rock. This is a type of rock that can develop caves because the rock dissolves when underground water is even slightly acidic. When the bridge over one of these caves collapses, a sinkhole occurs.

The second type is associated with water supply or sewage pipes buried underground. The sediment next to the pipes can erode or wash away when there is a leak in the pipes. That leaves a gap, and if the collapse at the surface becomes big enough, it becomes a sinkhole.

What do we know about the sinkholes in West Oak Lane and on the Schuylkill River Trail?

West Oak Lane experienced two recent water main breaks. Debris from the flowing water made it hard to get to the leak.

Fixing a big leak is a complex job. You have to stop the leak, clear out the debris, get the parts for repair, do the pipe repair, then repair the road. This example also shows that repair teams need to look around to see whether other sections of pipe might be aging and repair them while they have a hole opened up, so you don’t want to rush the job.

The sinkhole on the Schuylkill River Trail late last year, which took two months to fix, was also the result of a pipe leak. The water department had to get involved in the repair, alongside the parks and recreation department. I should point out that the city has a limited budget for pipe repair. As one of the oldest cities in the country, Philadelphia has a lot of work to keep up with.

That said, I would rather try to fix a pipe leak than a carbonate rock sinkhole. With the cavities in carbonate rock, you don’t really know how big they are, and a typical solution is to fill them with concrete. Sometimes you have a much bigger cavity than your supply of concrete.

Is Philly prone to sinkholes?

The Philadelphia region has both types of sinkholes. Within the city, there isn’t carbonate rock present, but just outside the city, such as the King of Prussia area, we see carbonate rock that is subject to sinkholes.

The sinkholes that occur in Philly are where pipes leak and the surrounding soil gets washed away. Because we have the right geology for sinkholes in our region and we have an extensive water network that is aging, sinkholes are somewhat common.

Some regions have even more sinkholes than we see here, however. Florida is entirely underlain by carbonate rock, and sinkholes are quite common.

Can nearby residents know when a sinkhole is forming?

We have a map of carbonate rock in the state, but not all carbonate rock develops sinkholes. Where and when in the carbonate rock a sinkhole is likely to develop is unpredictable.

Sinkholes in Philadelphia tend to also be unpredictable because the driving factor is happening underground and out of sight. We don’t know when a pipe leak is going to occur. Sometimes there is a sagging at the surface before a bigger hole opens up. Sometimes we see the leak before the sinkhole occurs. But not all leaks or sagging ground will lead to a sinkhole, and there won’t necessarily be any warning.

That said, it is important to report leaks and sagging ground so that they can be investigated before getting worse. Report leaks to the Philadelphia Water Department by calling their emergency hotline at 215-685-6300.

If we could replace all the aging infrastructure in the city, we would have fewer sinkholes. However, that would be costly and disruptive, so it really isn’t practical. In the meantime, the city just has to fix new sinkholes as they occur.

Read more of our stories about Philadelphia and Pennsylvania, or sign up for our Philadelphia newsletter on Substack.

Laura Toran receives funding from the National Science Foundation (federal), the Pennsylvania Department of Transportation, and the William Penn Foundation (private).

– ref. Why Philly has so many sinkholes – https://theconversation.com/why-philly-has-so-many-sinkholes-273082

Source: The Conversation – USA (2) – By Carrie Leach, Research Assistant Professor, Wayne State University

For the past 10 years, I have worked on closing the communication gaps that keep older adults at arm’s length from research that could improve their lives.

I worked with Detroiters to bridge the digital divide by developing tools that make it easier for older adults to get online, allowing them to connect to health information and learn about benefits they’re eligible for. I have also codesigned projects with members of the community to help improve older residents’ access to services.

My overriding goal is to help older minority adults connect with research so they are not left out of the very studies meant to reduce health disparities in aging. My work has focused on older adults in Detroit, a majority minority city, to help improve health for all residents.

Despite my best intentions, I recently had an experience where my work created unintended harm for vulnerable people.

I want to share my experience as a cautionary example of how researchers can fail to understand the government benefits that low-income older adults rely on, especially when it comes to research stipends.

Detroit seniors, unplugged

Recently, I completed a project that aimed to bridge both the digital divide and the divide between Detroit residents and researchers.

This project was inspired by the COVID-19 pandemic, when it became clear how hard it was going to be to connect with Detroit residents. Delivering environmental education and outreach is part of my work at the Center for Urban Responses to Environmental Stressors, also known as CURES. In response to the disconnect caused by the lockdown, our team was fortunate to get funding to deliver computers to 1,700 older Detroiters. Our community partners and advisory board members helped us distribute them.

But we soon learned many of the recipients didn’t know how to use the computers, and some couldn’t get online. At the time, Detroit had one of the lowest internet connectivity rates in the nation. Rates were as low as 40% in 2020.

Poor connectivity has been called a “super-determinant” of health. Not being able to access the internet harms individuals because they are cut off from resources that could make them healthier – such as telehealth appointments, for example. It also creates health inequities for groups of people when research lacks a diversity of perspectives.

Naturally, our next step was to develop tools to help the people who received computers get plugged in. We applied for funding, won it – and soon I was working alongside community health and aging advocates, researchers, service providers and housing administrators to develop and refine a technology tool kit.

Once the tool kit was ready, we distributed it widely. The tool kit is designed to cover the basics for older adults who are new computer users. For example, we included directions for connecting to Wi-Fi and creating an email account. We made this resource available for anyone who is interested in using it.

Intro to Research 101

Our community partners next gathered a cohort of 10 Detroiters who were 65 or older so they could learn how to get involved in virtual research. We developed an online research readiness curriculum to introduce them to the basics of how research is done.

Remembering the challenges of COVID-19, we set a goal of engaging the older adults entirely online. Our early meetings started with 45 minutes spent troubleshooting cameras and microphone connections. A few months later, we were all camera-ready in less than nine minutes.

Because I value their time, I budgeted to pay everyone involved in the project. It is difficult for people to take part in programs when they can’t afford to cover basic expenses, and payment can help relieve these financial pressures. What I didn’t realize is that these modest amounts of money could be treated by HUD as income and trigger increases in rent.

But that is exactly what happened.

The older adults involved in our project lived in HUD housing, and their rental costs are based on their income.

We paid residents $120 monthly. This stipend increased their incomes, which in turn led to increases in their rent, sometimes by the same amount as the stipend. Having higher housing costs left them in worse shape than before they joined our project. The stipends were designed to phase out after 10 months, but it was unclear when their rents would be adjusted again. By being involved, their finances became more precarious.

In my opinion, this illustrates how research involvement, even when designed to be fair and respectful, can create an unintended financial strain for people whose budgets leave no room for error.

My privilege was a blind spot.

Problem-solving through partnership

I would likely never have known about the problem if the housing administrator, who was one of my project partners, had not spoken up on behalf of the residents involved in the project. The residents did not come to me to report the issue. They went to a person they already knew and trusted to talk about the unexpected burden.

Some residents stopped accepting payments for their participation, but they still faced months of higher rental costs while we worked to get their money back.

That relief eventually came, thanks to a vigilant HUD administrator, weeks of calls and emails, and late nights spent reviewing HUD’s policies.

In the end, HUD emailed to say it had agreed to exempt the stipends from the residents’ income because we argued that the payments were “temporary, sporadic and nonrecurring.” In response, the HUD site administrator immediately made adjustments, and the overpayments were returned to the residents.

Everyone involved was hugely relieved.

Learning from my mistake

And that may have been the end of the story if one of my community partners, Zachary Rowe, hadn’t encouraged me to write about what happened so that others could learn from our experience.

In my view, this cautionary tale reveals a critical gap in how researchers engage and support people who are underrepresented in studies, including those who rely on housing assistance and other safety net programs. Without attention to these details, efforts to broaden participation in studies can unintentionally exclude or burden the very people researchers are working to include. Experiences like this reinforce that institutions must adapt their policies so paying people for their time never jeopardizes their basic needs.

Researchers, university research review boards and community partners could all benefit from plain‑language guidance about how earnings interact with safety net programs, benefits and income rules. Projects should start with collaborative efforts to anticipate the real-world implications of engagement.

This kind of persistent troubleshooting supports ethical practices and helps build the kind of trust that makes long‑term research partnerships possible.

I view the additional effort and advocacy required to take these precautions as part of the work of shaping who gets represented in research at all. If engaging people with complex lives and constrained resources were easy, our study samples would already be diversified.

Sharing these difficult experiences can be uncomfortable, but it can also help researchers, institutions and partners do better for those who might otherwise be harmed along the way.

Carrie Leach receives funding from NIH.

– ref. Some hard-earned lessons from Detroit on how to protect the safety net for community partners in research – https://theconversation.com/some-hard-earned-lessons-from-detroit-on-how-to-protect-the-safety-net-for-community-partners-in-research-271361

Source: The Conversation – USA (3) – By Jenni Shearston, Assistant Professor of Integrative Physiology, University of Colorado Boulder

I grew up in rural Colorado, deep in the mountains, and I can still remember the first time I visited Denver in the early 2000s. The city sits on the plain, skyscrapers rising and buildings extending far into the distance. Except, as we drove out of the mountains, I could barely see the city – the entire plain was covered in a brown, hazy cloud.

That brown, hazy cloud was mostly made of ozone, a lung-irritating gas that causes decreases in lung function, inflammation, respiratory symptoms like coughing, and can trigger asthma attacks.

Denver still has air pollution problems, due in part to its geography, which creates temperature inversions that can hold pollution near the ground. But since 1990, ozone has decreased 18% across the U.S., reducing the smog that choked many cities in the 1960s and 1970s. The concentration of tiny dustlike particles of air pollution called PM2.5 has also decreased, by 37% since 2000.

These decreases occurred largely because of one of the most successful public health policies ever implemented by the United States: the Clean Air Act, first passed in 1970. The Clean Air Act regulates air pollution emissions and authorizes the Environmental Protection Agency to set air quality standards for the nation.

For years, when the Environmental Protection Agency assessed the economic impact of new regulations, it weighed both the health costs for Americans and the compliance costs for businesses. The Trump administration is now planning to drop half of that calculation – the monetary health benefits of reducing both ozone and PM2.5 – when weighing the economic impact of regulating sources of air pollution.

I am an environmental epidemiologist, and one of the things I study is people’s exposure to air pollution and how it affects health. Measuring the impact of air quality policies – including quantifying how much money is saved in health care costs when people are exposed to less air pollution – is important because it helps policymakers determine if the benefits of a regulation are worth the costs.

What air pollution does to your body

Breathing in air pollution like ozone and PM2.5 harms nearly every major system in the human body.

It is particularly hard on the cardiovascular, respiratory and neurological systems. Numerous studies have found that PM2.5 exposure is associated with increased death from cardiovascular diseases like coronary heart disease. Even short-term exposure to either PM2.5 or ozone can increase hospitalizations for heart attacks and strokes.

In the respiratory system, PM2.5 exposure is associated with a 10% increased risk for respiratory diseases and symptoms such as wheezing and bronchitis in children. More recent evidence suggests that PM2.5 exposure can increase the risk of Alzheimer’s disease and other cognitive disorders. In addition, the International Agency for Research on Cancer has designated PM2.5 as a carcinogen, or cancer-causing agent.

Reducing air pollution has been proven to save lives, reduce health care costs and improve quality of life.

For example, a study led by scientists at the EPA estimated that a 39% nationwide decrease in airborne PM2.5 from 1990 to 2010 corresponded to a 54% drop in deaths from ischemic heart disease, chronic obstructive pulmonary disease, lung cancer and stroke.

In the same period, the study found that a 9% decline in ozone corresponded to a 13% drop in deaths from chronic respiratory disease. All of these illnesses are costly for the patients and the public, both in the treatment costs that raise insurance prices and the economic losses when people are too ill to work.

Yet another study found that nationally, an increase of 1 microgram per square meter in weekly PM2.5 exposure was associated with a 0.82% increase in asthma inhaler use. The authors calculated that decreasing PM2.5 by that amount would mean US$350 million in annual economic benefits.

Especially for people with lung diseases like asthma or sarcoidosis, increased PM2.5 concentrations can reduce quality of life by worsening lung function.

Uncertainty doesn’t mean ignore it

The process of calculating precisely how much money is saved by a policy has uncertainty. That was a reason the Trump administration stated for not including health costs in its cost-benefit analyses in 2026 for a plan to change air pollution standards for power plant combustion turbines.

Uncertainty is something we all deal with on a daily basis. Think of the weather. Forecasts have varying degrees of accuracy. The high temperature might not get quite as high as the prediction, or might be a bit hotter. That is uncertainty.

The EPA wrote in a notice dated Jan. 9, 2026, that its historical practice of providing estimates of the monetized impact of reducing pollution leads the public to believe that the EPA has a clearer understanding of these monetary benefits than it actually does.

Therefore, the EPA wrote, the agency will stop estimating monetary benefits from reducing pollution until it is “confident enough in the modeling to properly monetize those impacts.”

This is like ignoring weather forecasts because they might not be perfect. Even though there is uncertainty, the estimate is still useful.

Estimates of the monetary costs and benefits of regulating pollution sources are used to understand if the regulation is worth its cost. Without considering the health costs and benefits, it may be easier for infrastructure that emits high levels of air pollution to be built and operated.

What the evidence shows

Several studies have shown the impact of pollution sources like power plants on health.

For example, the retirement of coal and oil power plants has been connected with a reduction in preterm birth to mothers living near the power plants. Scientists studied 57,000 births in California and found the percentage of babies born preterm to mothers living within 3.1 miles (5 kilometers) of a coal- or oil-fueled power plant fell from 7% to 5.1% after the power plant was retired.

Another study in the Louisville, Kentucky, area found that four coal-fired power plants either retiring or installing pollution-reduction technologies such as flue-gas desulfurization systems coincided with a drop in hospitalizations and emergency department visits for asthma and reduced asthma-medication use.

Reducing preterm birth, hospitalizations, emergency department visits and medication use saves money by preventing expensive health care for treatment, hospital stays and medications. For example, researchers estimated that for children born in 2016, the lifetime cost of preterm birth, including medical and delivery care, special education interventions and lost productivity due to disability in adulthood, was in excess of $25.2 billion.

Circling back to Denver: The region is a fast-growing data center hub, and utilities are expecting power demand to skyrocket over the next 15 years. That means more power plants will be needed, and with the EPA’s changes, they may be held to lower pollution standards.

Jenni Shearston has received funding from the National Institutes of Health.

– ref. What air pollution does to the human body – https://theconversation.com/what-air-pollution-does-to-the-human-body-273456

Source: The Conversation – USA (3) – By Joanne M. Pierce, Professor Emerita of Religious Studies, College of the Holy Cross

Pope Leo XIV closed the door at St. Peter’s Basilica on Jan. 6, 2026, just days into the new year. The act formally brought the Vatican’s Holy Year 2025 – designated as “Pilgrims of Hope” – to an end.

In 2022, after the COVID-19 pandemic ended, Pope Francis announced his intention to proclaim a Jubilee year, urging the faithful to look to the future “with an open spirit, a trusting heart and far-sighted vision.” That is why, as Francis explained, he chose the motto of the Jubilee: “Pilgrims of Hope.”

Ironically, 2025 was a turbulent year the world over. After so much military aggression in Ukraine, rampant starvation in Gaza and increasing violence of all kinds within the United States, people in many parts of the world were left much more despairing than hopeful for 2026.

Religions typically try to offer hope in the face of despair. As a scholar of Catholicism, I know that even amid violent persecutions, devastating wars and staggering death tolls from epidemics, Christians have repeatedly turned to their holy texts for hope.

So what is the meaning of hope in the Christian tradition?

Western antiquity

Christianity was shaped by its roots in Judaism, but also its rejection of Greco-Roman religious culture, especially its polytheism.

Many ancient Greek authors wrote about a divine spirit of hope – Elpis. As early as the late eighth century B.C.E., the poet Hesiod composed a mythic poem, “Works and Days,” about Pandora and her box of woes. The god Zeus warned that Pandora was not to open the box, given to her as a gift. But in the end, she did – and released all of the entrapped evils to trouble the world. But Elpis – that is, Hope – had also been placed in the box and was kept inside when Pandora closed the lid quickly. The moral of the story is that hope still remains with humanity.

In ancient Rome, hope was venerated as a minor goddess, Spes, but usually on a communal, national level. Politically, Spes represented the collective hope for the Roman Republic or support for the semi-divine emperors of the later empire; temples were erected in her honor, and her image could be found on coins.

Hebrew Scriptures

But for monotheistic Judaism, hope was not an external divine spirit or goddess to be invoked in times of personal or communal need.

In the ancient Near East, the authors of books of the Hebrew Bible spoke frequently about hope. Often expressed with the word “tikvah,” hope is presented in the Bible as a human reaction to God’s promises, “an inner attitude of inner expectation”: a confident trust based on God’s past works.

Early in the Book of Job, the reader meets Job, a righteous man whose faith is tested through the sudden loss of his children, wealth and health. His friend Eliphaz urges him not to give up hope in the midst of Job’s terrible sufferings. He asks: “Is your fear of God not your confidence, and the integrity of your ways your hope?” Job is already living a life of faith and obedience; his reaction should not be to collapse in despair, but to carry on in hope, trusting in God’s wisdom and mercy.

The Psalms were composed as poems or hymns used in worship. In Psalm 62, the psalmist reminds himself and all God’s people of this hope: “My soul, wait in silence for God alone, for my hope is from Him. … Trust in Him at all times, you people.”

The prophets were understood to have been sent by God to chastise the people of Israel for falling into idolatry and other evils and to urge repentance. And some of them stress hope in God as the source for strength in rejecting these worldly temptations and turning back to following the teachings of the Scriptures. The prophet Jeremiah, for example, addresses God as “the hope of Israel” as they repent.

Christian Scriptures

The New Testament, compiled in the first century C.E. contains frequent references to the Old Testament as interpreted through the lens of Jesus’ teaching.

The Gospels rarely use the word hope itself, but imply it obliquely in connection with other elements of faith, such as belief and trust. The Epistles, or letters, by early Christian apostles and their followers, contain frequent references to hope.

For example, in several Epistles, the apostle Paul speaks often about the Christian hope in God through Jesus Christ. In the “Letter to the Romans,” Paul states that, even among difficulties, “hope does not disappoint us, because God’s love has been poured into our hearts.” He praises the Christians in Thessalonika for “your work of faith and labor of love and endurance in hope of our Lord Jesus Christ, before our God and Father.”

But in his first “Letter to the Corinthians,” Paul addresses different kinds of spiritual gifts – some very striking, such as speaking in tongues or healing others. But he then writes a section specifically exploring the most important gift of all, love – in Greek, “agape” – and refers to its relationship with both faith and hope. He closes with a frequently quoted text about what he described as the three greatest Christian virtues: faith, hope and love.

Contemporary hope

Throughout the next centuries, Christian theologians and popes reflected on the nature of hope – either in itself, or within the framework of all three of these virtues.

And so, on Dec. 24, 2025, Francis opened the door of St. Peter’s Basilica to declare the beginning of the Catholic Church’s celebration of the Holy Year, with hope as the special theme.

He would not live to close it. But Leo XIV did, with the following words at the final Jubilee Mass:

“Has the Jubilee taught us to flee from (the) type of efficiency that reduces everything to a product and human beings to consumers? After this year, will we be better able to recognize a pilgrim in the visitor, a seeker in the stranger, a neighbor in the foreigner, and fellow travelers in those who are different?”

From his very first speech after being elected pope, Leo called Christians to reach out to others, build bridges, engage in dialogue and be present to one another.

Perhaps this is what continuing to hope means for the world in 2026.

Joanne M. Pierce does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. What ‘hope’ has represented in Christian history – and what it might mean now – https://theconversation.com/what-hope-has-represented-in-christian-history-and-what-it-might-mean-now-273097

Source: The Conversation – USA – By Alessandra Buccella, Assistant Professor of Philosophy, University at Albany, State University of New York

Consistent with the general trend of incorporating artificial intelligence into nearly every field, researchers and politicians are increasingly using AI models trained on scientific data to infer answers to scientific questions. But can AI ultimately replace scientists?

The Trump administration signed an executive order on Nov. 24, 2025, that announced the Genesis Mission, an initiative to build and train a series of AI agents on federal scientific datasets “to test new hypotheses, automate research workflows, and accelerate scientific breakthroughs.”

So far, the accomplishments of these so-called AI scientists have been mixed. On the one hand, AI systems can process vast datasets and detect subtle correlations that humans are unable to detect. On the other hand, their lack of commonsense reasoning can result in unrealistic or irrelevant experimental recommendations.

While AI can assist in tasks that are part of the scientific process, it is still far away from automating science – and may never be able to. As a philosopher who studies both the history and the conceptual foundations of science, I see several problems with the idea that AI systems can “do science” without or even better than humans.

AI models can only learn from human scientists

AI models do not learn directly from the real world: They have to be “told” what the world is like by their human designers. Without human scientists overseeing the construction of the digital “world” in which the model operates – that is, the datasets used for training and testing its algorithms – the breakthroughs that AI facilitates wouldn’t be possible.

Consider the AI model AlphaFold. Its developers were awarded the 2024 Nobel Prize in chemistry for the model’s ability to infer the structure of proteins in human cells. Because so many biological functions depend on proteins, the ability to quickly generate protein structures to test via simulations has the potential to accelerate drug design, trace how diseases develop and advance other areas of biomedical research.

As practical as it may be, however, an AI system like AlphaFold does not provide new knowledge about proteins, diseases or more effective drugs on its own. It simply makes it possible to analyze existing information more efficiently.

As philosopher Emily Sullivan put it, to be successful as scientific tools, AI models must retain a strong empirical link to already established knowledge. That is, the predictions a model makes must be grounded in what researchers already know about the natural world. The strength of this link depends on how much knowledge is already available about a certain subject and on how well the model’s programmers translate highly technical scientific concepts and logical principles into code.

AlphaFold would not have been successful if it weren’t for the existing body of human-generated knowledge about protein structures that developers used to train the model. And without human scientists to provide a foundation of theoretical and methodological knowledge, nothing AlphaFold creates would amount to scientific progress.

Science is a uniquely human enterprise

But the role of human scientists in the process of scientific discovery and experimentation goes beyond ensuring that AI models are properly designed and anchored to existing scientific knowledge. In a sense, science as a creative achievement derives its legitimacy from human abilities, values and ways of living. These, in turn, are grounded in the unique ways in which humans think, feel and act.

Scientific discoveries are more than just theories supported by evidence: They are the product of generations of scientists with a variety of interests and perspectives, working together through a common commitment to their craft and intellectual honesty. Scientific discoveries are never the products of a single visionary genius.

For example, when researchers first proposed the double-helix structure of DNA, there were no empirical tests able to verify this hypothesis – it was based on the reasoning skills of highly trained experts. It took nearly a century of technological advancements and several generations of scientists to go from what looked like pure speculation in the late 1800s to a discovery honored by a 1953 Nobel Prize.

Science, in other words, is a distinctly social enterprise, in which ideas get discussed, interpretations are offered, and disagreements are not always overcome. As other philosophers of science have remarked, scientists are more similar to a tribe than “passive recipients” of scientific information. Researchers do not accumulate scientific knowledge by recording “facts” – they create scientific knowledge through skilled practice, debate and agreed-upon standards informed by social and political values.

AI is not a ‘scientist’

I believe the computing power of AI systems can be used to accelerate scientific progress, but only if done with care.

With the active participation of the scientific community, ambitious projects like the Genesis Mission could prove beneficial for scientists. Well-designed and rigorously trained AI tools would make the more mechanical parts of scientific inquiry smoother and maybe even faster. These tools would compile information about what has been done in the past so that it can more easily inform how to design future experiments, collect measurements and formulate theories.

But if the guiding vision for deploying AI models in science is to replace human scientists or to fully automate the scientific process, I believe the project would only turn science into a caricature of itself. The very existence of science as a source of authoritative knowledge about the natural world fundamentally depends on human life: shared goals, experiences and aspirations.

Alessandra Buccella does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. AI cannot automate science – a philosopher explains the uniquely human aspects of doing research – https://theconversation.com/ai-cannot-automate-science-a-philosopher-explains-the-uniquely-human-aspects-of-doing-research-272477

Source: The Conversation – USA – By Pardis Mahdavi, Professor of Anthropology, University of La Verne; University of California, Berkeley

Iran’s current wave of protests continues to spread across the country, as the United States weighs military intervention. Meanwhile, many Iranian people continue to struggle to pay for basic necessities amid a collapsing currency.

The anti-government demonstrations began in Tehran’s Grand Bazaar, one of the largest and oldest covered markets in the world, in December 2025. From there, they quickly reached Iran’s university campuses.

The government’s response was swift and familiar: Authorities ordered universities to move classes online, citing weather concerns. When students continued organizing, the regime closed universities entirely.

I am an Iranian-American who has studied Iranian social movements for more than 25 years. As an educator, I have also led American universities, while maintaining ties to Iranian academic institutions.

I also witnessed firsthand the systematic assault on academic freedom during the presidency of Mahmoud Ahmadinejad from 2005 through 2013.

Iran’s universities tell the story of the nation itself: a story of persistent hope confronting relentless repression, and of intellectual life refusing to be extinguished even under extraordinary pressure.

Iranian universities have long been places of political reform and imagination – and where the Islamic Republic’s authoritarian impulses collide with people’s demands for freedom.

The heartbeat of reform

Iran has 316 accredited universities across the country, including the University of Tehran and Islamic Azad University.

Iranian universities have been hubs of political activity and protest since at least the mid-1900s.

Student-led protest movements emerged forcefully in the 1940s following the abdication of Reza Shah, an Iranian military officer who led Iran as its shah, or monarch, from 1925 to 1941.

These groups gained momentum during the oil nationalization movement led by the democratically elected Prime Minister Mohammad Mossadegh. Students supported Mossadegh’s promises of a democratic and free Iran, where the benefits of resources – like oil – would be reaped by Iranians first, before extending to the rest of the world.

The United States led a CIA-backed military coup that overthrew Mossadegh and reinstated Mohammad Reza Pahlavi as shah of Iran in 1953.

College campuses again became critical spaces for political consciousness and opposition.

A long-established pattern

This pattern continued for decades. Universities were central to the 1979 revolution, with students joining clerics, leftists and nationalists in overthrowing the monarchy.

Yet once consolidated, the Islamic Republic quickly turned against the institutions that had helped make the revolution possible.

The 1980s and 1990s saw widespread purges of faculty, with the imprisonment of professors in such numbers that the notorious Evin Prison came to be grimly nicknamed “Evin University.”

Academic life was tightly policed, books were routinely banned, and government surveillance became routine. As Azar Nafisi later documented in the 2003 book “Reading Lolita in Tehran,” intellectual engagement often survived only through clandestine reading groups and private gatherings.

Yet repression never succeeded in erasing student activism. When formal organizing became impossible, it moved underground. When campuses were locked down, ideas continued to circulate.

Thaw, reversal and academic repression

The election of Mohammad Khatami in 1997 briefly altered this trajectory of academic repression.

Khatami ran for office as a reformist candidate with strong support from young people. As president, he presided over a limited thaw in academic life. Universities reopened slightly as spaces for debate and research.

I conducted fieldwork on the youth movement and sexual revolution in Iran beginning in 1999 – research that would have been unthinkable just a few years earlier.

But the opening proved fragile. Ahmadinejad’s rise to power in 2005 marked a return to aggressive repression. Universities were again treated as ideological threats. Some faculty members were arrested or dismissed, student organizations were dismantled, and coursework and readings were heavily censored.

The irony was stark. By the mid-2000s, Iran had one of the highest literacy rates and highest proportions of college graduates per capita in the region.

Yet the government began restricting which majors women could study and which subjects could be taught. Entire fields, including engineering, education and counseling, were deemed suspect. Professors who resisted faced harassment and dismissal. Student protests were met with force and detention.

Despite this, youth-led mobilization persisted. Every major protest cycle over the past two decades – including the 1999 student uprising – has been driven by young people, many of them university students.

Universities in the current uprising

Recent Iranian university closures underscore the regime’s likely fears of resistance – not simply because of what is taught in classrooms, since curricula can be controlled – but also because of the power that young people can gain when they physically gather in shared spaces.

Dormitories, libraries and cafeterias are where political awareness coalesces, where individual grievances become collective demands, and where dissent acquires momentum.

Today, by systematically alienating young people through economic mismanagement, social repression and the erosion of academic freedom, the government has created its most formidable opposition: young protesters. Analysts have increasingly identified this pattern as one of the regime’s central strategic failures.

Universities are a lens into Iran

What happens inside Iran’s universities today is not a side story – it is one of the clearest indicators of where the country may be headed.

The freedom to teach, read, question and debate mirrors the freedom Iranian citizens seek in public life more broadly. Just as women have pushed back against state control of their bodies one millimeter at a time, universities have pushed back against intellectual confinement one page at a time – expanding the boundaries of permissible thought even under threat of punishment.

For decades, Iranian students and professors have demonstrated extraordinary courage in sustaining these small but vital acts of defiance. They have kept alive what Iranians call “koorsoo”: a small, stubborn flame of hope that endures even in darkness.

History suggests that societies which wage war on their intellectual institutions ultimately lose more than control – they lose legitimacy. Iran’s universities have long been the heartbeat of reform. Today, that heartbeat is growing louder – and it may once again shape the course of the nation’s history.

Pardis Mahdavi does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Iran’s universities have long been a battleground, where protests happen and students fight for the future – https://theconversation.com/irans-universities-have-long-been-a-battleground-where-protests-happen-and-students-fight-for-the-future-273742

Source: The Conversation – USA (2) – By Christos Makridis, Associate Research Professor of Information Systems, Arizona State University; Institute for Humane Studies

Every few years, you’ll hear a familiar refrain: “Opera is dying.”

National surveys point to slumping attendance at live performances. Audiences are aging, leaving fewer fans to fill seats at productions of “La Bohème,” “Carmen,” “The Magic Flute” and the like, while production costs grow.

I’m a labor economist who studies the economics of art and culture. To
assess the state of opera in the U.S., I analyzed financial data collected by Opera America, an association whose roughly 600 members are overwhelmingly nonprofit opera companies.

After crunching the numbers, as I explained in a 2026 paper published in the Journal of Arts Management, Law, and Society, I reached a surprising conclusion about the state of those nonprofits.

Funding model is faltering

Although opera companies are experiencing financial stress, opera isn’t a dying art form. Instead, I found that the public’s demand for meaningful, live cultural experiences – including opera – remains strong.

That said, opera’s traditional business model is faltering.

Opera is, for the most part, stuck in the past. Many companies still depend on a business model that relies on season ticket sales and a small circle of big donors. This approach worked better in the 20th century than it does now.

Few opera companies have embraced strategies the rest of the entertainment industry regularly uses: audience data analysis, experimentation with digital content and streaming, and engagement through online platforms rather than brochures.

In other words, opera management practices, metrics and audience development tactics didn’t change much even as the world transitioned into the digital age.

Change is needed because subscriptions and individual ticket sales have declined for many companies, especially those with budgets above US$1 million.

The number of opera tickets those companies sold fell 21% between 2019 and 2023. Ticket revenue fell 22% over the same period.

Meanwhile, opera companies received 19% of their budgets from donations and grants in 2023, down from roughly 25% in 2019, as earned revenue weakened and fundraising failed to fully recover.

Opera companies receive more than twice as much funding from philanthropy as from government sources. Government support was low and relatively stable prior to 2020 and rose sharply during the first two years of the COVID-19 pandemic before declining again to roughly 8% of operating revenue by 2023.

Managing institutions in trouble

I don’t dispute that opera’s economic woes are troubling. But I don’t see them as a sign that this art form is in cultural decline. Instead, I believe that opera institutions need to modernize how they operate.

Audiences continue to respond to the repertoire when companies find new ways to tell familiar stories.

Productions of canonical works such as La Traviata and Don Giovanni that place well-known narratives in contemporary settings or reframe them through modern staging have drawn strong attendance and critical attention. Crossover projects that bring operatic voices into dialogue with jazz, musical theater or popular musical performance have also sold out limited runs aimed at new audiences.

And smaller-scale formats, including chamber operas and performances staged in studios or alternative venues, have consistently filled seats – even as large main-stage productions struggle to sell tickets.

Those examples point to underlying demand for experiencing operas – even if fewer people are buying season tickets.

To be sure, there are some signs of progress. Some opera companies are taking their digital productions seriously.

Boston Baroque is primarily an orchestra and chorus, but it also produces staged operas. It offered livestreams of its performances during the pandemic to earn extra money.

New York City’s Metropolitan Opera has maintained a standalone direct-to-consumer subscription product, Met Opera on Demand, that anyone in the world can access. But it illustrates the strategic tension many companies face: Digital expansion can broaden reach, but it may also complicate efforts to fill empty seats.

Grappling with an economic problem

Opera’s biggest challenge is structural, not artistic.

Live performance is inherently labor intensive – and expensive. You cannot automate a string quartet or speed up an aria without destroying what makes it valuable.

Notably, opera companies have nearly doubled administrative costs as a share of their budgets since the mid-2000s, while spending on artistic programming has remained flat.

Some of the increase in administrative spending reflects the growing complexity of fundraising, compliance and labor management. But the magnitude of the shift strongly suggests declining organizational efficiency, with managerial and overhead functions expanding faster than opera’s capacity to stage productions or build its audience in the United States.

Meanwhile, ticket sales have declined and the number of major opera donors has declined.

Facing a similar turning point

Financial distress is not unique to opera.

Many U.S. orchestras have confronted serious financial stress, including bankruptcies and closures in places like Honolulu, Syracuse, N.Y. and Albuquerque, N.M..

The orchestras that survived tended to diversify revenue, analyze data and treat innovation as part of their mission – three strategies opera companies have failed to pursue consistently.

Reaching the public where it already is

The assumption that younger generations do not care about classical music is unfounded.

When opera companies put performances on streaming platforms during the pandemic, many younger listeners tuned in.

A 2022 survey of music consumption in the United Kingdom conducted by the Royal Philharmonic Orchestra; Deezer, one of several global services tracking the digital consumption of classical music; and the British Phonographic Industry found that 59% of people under 35 streamed orchestral music during the COVID-19 lockdown, compared with a 51% national average across all age groups.

Meanwhile, classical music streaming rose sharply across digital platforms during the first months of the pandemic. Deezer reported a 17% increase in classical streams in the 12 months beginning in April 2019.

These patterns suggest that younger audiences can become interested in opera and classical music when access to those genres is easy, and that digital formats can meaningfully expand the base of younger listeners.

But younger audiences usually encounter the music they listen to through algorithms or short-form video.

Treating performances as content

The lesson is not that opera should abandon live performance – if anything, everyone needs more, not less, in-person interaction in this hybrid-work era. Instead, I believe that opera companies should treat performances as content that can be accessed both in person and in digital spaces.

That way, they can spread those fixed artistic costs across multiple formats and markets, whether they’re recordings, livestreams, educational licenses or smaller-scale spinoff events.

Opera has survived wars, depressions, technological revolutions and cultural upheavals because it evolved. Today, the risk is not that people have stopped caring about music; it’s that opera companies have presumed that upholding tradition requires a rigidity at odds with their own success.

Christos Makridis is also a co-founder of Living Opera and the Living Opera Foundation and founder of CM Culture Management. He is also an affiliate and contributor to several think tank communities across the aisles.

– ref. Opera is not dying – but it needs a second act for the streaming era – https://theconversation.com/opera-is-not-dying-but-it-needs-a-second-act-for-the-streaming-era-271376

Source: The Conversation – USA – By Donald Heflin, Executive Director of the Edward R. Murrow Center and Senior Fellow of Diplomatic Practice, The Fletcher School, Tufts University

Make Denmark angry. Make Norway angry. Make NATO’s leaders angry.

President Donald Trump’s relentless and escalating drive to acquire Greenland from Denmark, whose government – along with that of Greenland – emphatically rejects the idea, has unnerved, offended and outraged leaders of countries considered allies for decades.

It’s the latest, and perhaps most significant, eruption of an attitude of disdain towards allies that has become a hallmark of the second Trump administration, which has espoused an America First approach to the world.

Trump, Vice President JD Vance and Defense Secretary Pete Hegseth have all said a lot of things about longtime allies that have caused frustration and outright friction among the leaders of those countries. The latest discord over Greenland could affect the functioning and even existence of NATO, the post-World War II alliance of Western nations that “won the Cold War and led the globe,” as a recent Wall Street Journal story put it.

As a former diplomat, I’m aware that how the U.S. treats its allies has been a crucial question in every presidency, since George Washington became the country’s first chief executive. On his way out of that job, Washington said something that Trump, Vance and their fellow America First advocates would probably embrace.

In what’s known as his “Farewell Address,” Washington warned Americans against “entangling alliances.” Washington wanted America to treat all nations fairly, and warned against both permanent friendships and permanent enemies.

The irony is that Washington would never have become president without the assistance of the not-yet-United-States’ first ally, France.

In 1778, after two years of brilliant diplomacy by Benjamin Franklin, the not-yet-United States and the Kingdom of France signed a treaty of alliance as the American Colonies struggled to win their war for independence from Britain.

France sent soldiers, money and ships to the American revolutionaries. Within three years, after a major intervention by the French fleet, the battle of Yorktown in 1781 effectively ended the war and America was independent.

Isolationism, then war

American political leaders largely heeded Washington’s warning against alliances throughout the 1800s. The Atlantic Ocean shielded the young nation from Europe’s problems and many conflicts; America’s closest neighbors had smaller populations and less military might.

Aside from the War of 1812, in which the U.S. fought the British, America largely found itself protected from the outside world’s problems.

That began to change when Europe descended into the brutality of World War I.

Initially, American politicians avoided involvement. What would today be called an isolationist movement was strong; its supporters felt that the European war was being waged for the benefit of big business.

But it was hard for the U.S.to maintain neutrality. German submarines sank ships crossing the Atlantic carrying American passengers. The economies of some of America’s biggest trading partners were in shreds; the democracies of Britain, France and other European countries were at risk.

President Woodrow Wilson led the U.S. into the war in 1917 as an ally of the Western European nations. When he asked Congress for a declaration of war, Wilson asserted the value of like-minded allies: “A steadfast concert for peace can never be maintained except by a partnership of democratic nations.”

Immediately after the war, the Allies – led by the U.S., France and Britain – stayed together to craft the peace agreements, feed the war-ravaged parts of Europe and intervene in Russia after the Communist Revolution there.

Prosperity came along with the peace, helping the U.S. quickly develop into a global economic power.

However, within a few years, American politicians returned to traditional isolationism in political and military matters and continued this attitude well into the 1930s. The worldwide Great Depression that began in 1929 was blamed on vulnerabilities in the global economy, and there was a strong sentiment among Americans that the U.S. should fix its internal problems rather than assist Europe with its problems.

Alliance counters fascism

As both Hitler and Japan began to attack their neighbors in the late 1930s, it became clear to President Franklin Roosevelt and other American military and political leaders that the U.S. would get caught up in World War II. If nothing else, airplanes had erased America’s ability to hide behind the Atlantic Ocean.

Though public opinion was divided, the U.S. began sending arms and other assistance to Britain and quietly began military planning with London. This was despite the fact that the U.S. was formally neutral, as the Roosevelt administration was pushing the limits of what a neutral nation can do for friendly nations without becoming a warring party.

In January of 1941, Roosevelt gave his annual State of the Union speech to Congress. He appeared to prepare the country for possible intervention – both on behalf of allies abroad and for the preservation of American democracy:

“The future and the safety of our country and of our democracy are overwhelmingly involved in events far beyond our borders. Armed defense of democratic existence is now being gallantly waged in four continents. If that defense fails, all the population and all the resources of Europe, and Asia, and Africa and Australasia will be dominated by conquerors. In times like these it is immature – and incidentally, untrue – for anybody to brag that an unprepared America, single-handed, and with one hand tied behind its back, can hold off the whole world.”

When the Japanese attacked Hawaii in 1941 and Hitler declared war on the U.S., America quickly entered World War II in an alliance with Britain, the Free French and others.
Throughout the war, the Allies worked together on matters large and small. They defeated Germany in three and half years and Japan in less than four.

As World War II ended, the wartime alliance produced two longer-term partnerships built on the understanding that working together had produced a powerful and effective counter to fascism.

Postwar alliances

The first of these alliances is the North Atlantic Treaty Organization, or NATO. The original members were the U.S., Canada, Britain, France and others of the wartime Allies. There are now 32 members, including Poland, Hungary and Turkey.

The aims of NATO were to keep peace in Europe and contain the growing Communist threat from the Soviet Union. NATO’s supporters feel that, given that wars in the former Yugoslavia in the 1990s and in the Ukraine today are the only major conflicts in Europe in 80 years, the alliance has met its goals well. And NATO troops went to Afghanistan along with the U.S. military after 9/11.

The other institution created by the wartime Allies is the United Nations.

The U.N. is many things – a humanitarian aid organization, a forum for countries to raise their issues and a source of international law.

However, it is also an alliance. The U.N. Security Council on several occasions authorized the use of force by members, such as in the first Gulf War against Iraq. And it has the power to send peacekeeping troops to conflict areas under the U.N. flag.

Other U.S. allies with treaties or designations by Congress include Australia, New Zealand, Japan, Israel, three South American countries and six in the Middle East.

Many of the same countries also created institutions such as the World Bank, the International Monetary Fund, the Organization of American States and the European Union. The U.S. belongs to all of these except the European Union. During my 35-year diplomatic career, I worked with all of these institutions, particularly in efforts to stabilize Africa. They keep the peace and support development efforts with loans and grants.

Admirers of this postwar liberal international order point to the limited number of major armed conflicts during the past 80 years, the globalized economy and international cooperation on important matters such as disease control and fighting terrorism.
Detractors point to this system’s inability to stop some very deadly conflicts, such as Vietnam or Ukraine, and the large populations that haven’t done well under globalization as evidence of its flaws.

The world would look dramatically different without the Allies’ victories in the two World Wars, the stable worldwide economic system and NATO’s and the U.N.’s keeping the world relatively peaceful.

But the value of allies to Americans, even when they benefit from alliances, appears to have shifted between George Washington’s attitude – avoid them – and that of Franklin D. Roosevelt – go all in … eventually.

_This is an updated version of an article originally published on Feb. 20, 2025. _

Donald Heflin does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Trump’s Greenland ambitions could wreck 20th-century alliances that helped build the modern world order – https://theconversation.com/trumps-greenland-ambitions-could-wreck-20th-century-alliances-that-helped-build-the-modern-world-order-273863

Source: The Conversation – USA – By Nilton O. Rennó, Professor of Climate and Space Sciences Engineering, University of Michigan

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com.

---

Are there thunderstorms on Mars? – Cade, age 7, Houston, Texas

Mars is a very dry planet with very little water in its atmosphere and hardly any clouds, so you might not expect it to have storms. Yet, there is lightning and thunder on Mars – although not with rain, nor with the same gusto as weather on Earth.

More than 10 years ago, my planetary science colleagues and I found the first evidence for lightning strikes on Mars. In the following decade, other researchers have continued to study what lightning might be like on the red planet. In November 2025, a Mars rover first captured the spectacular sounds of lightning sparking on the Martian surface.

Lightning on Mars

On Earth, lightning is an electric discharge that begins inside big clouds.

But because Mars is so dry, it doesn’t have clouds of water – instead, it has clouds of dust. With little water to weigh down dirt on Mars, dust clouds can quickly grow into huge, windy dust storms a few times taller than Earth’s tallest thunderstorms.

When smaller dust particles and larger sand particles collide with each other while being whipped around by these storms, they pick up a static charge. Smaller dust particles take on a positive charge, while larger sand particles become negative. The smaller dust particles are lighter and will float higher, while the heavier sand tends to fall closer to the ground.

Because oppositely charged particles don’t like to be apart, eventually the energy building between the negative charges higher up in the dust storm and the positive charges closer to the ground becomes too great and is released as electricity – similar to lightning.

The air around the electricity rapidly warms up and expands – on Earth, this creates the shock waves that you hear as thunder.

Nobody has seen a flash of lightning on Mars, but we suspect it’s more like the glow from a neon light rather than a powerful lightning bolt. The atmosphere near the surface of Mars is about 100 times less dense than on Earth: It’s much more similar to the air inside neon lights.

Releasing radio waves

Besides shock waves and visible light, lightning also produces other types of waves that the human eye can’t see: X-ray and radio waves. The ground and the top of the atmosphere both conduct electricity well, so they guide these radio waves and cause them to produce signals with specific radio frequencies. It’s kind of like how you might tune into specific radio channels for news or music, but instead of different channels, scientists can identify the radio waves coming from lightning.

While nobody has ever seen visible light from Martian lightning, we have heard something similar to the radio waves created by lightning on Earth. That’s the noise that the Perseverance rover reported at the end of 2025. They sound like electric sparks do on Earth. The rover recorded these signals on a microphone as small, sandy tornadoes passed by.

Searching for Martian lightning

When my colleagues and I went hunting for lightning on Mars a decade ago, we knew the red planet emitted more radio waves during dust storm seasons. So, we searched for modest increases in radio signals from Mars using the large radio dishes that NASA uses to talk to its spacecraft. The dishes function like big ears that listen for faint radio signals from spacecraft far from Earth.

We spent from five to eight hours every day listening to Mars for three weeks. Eventually, we found the signals we were looking for: radio bursts with frequencies that matched up with the radio waves that lightning on Earth can create.

To find the particular source of these lightning-like signals, we searched for dust storms in pictures taken by spacecraft orbiting Mars. We matched a dust storm nearly 25 miles (40 kilometers) tall to the time when we’d heard the radio signals.

Learning about lightning on Mars helps scientists understand whether the planet could have once hosted extraterrestrial life. Lightning may have helped create life on Earth by converting molecules of nitrogen and carbon dioxide in the atmosphere into amino acids. Amino acids make up proteins, tens of thousands of which are found in a human body.

So, Mars does have storms, but they’re far drier and dustier than the thunderstorms on Earth. Scientists are continually studying lightning on Mars to better understand the geology of the red planet and its potential to host living organisms.

---

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

Nilton O. Rennó receives funding from NASA, JPL, DARPA, and IARPA.

– ref. Are there thunderstorms on Mars? A planetary scientist explains the red planet’s dry, dusty storms – https://theconversation.com/are-there-thunderstorms-on-mars-a-planetary-scientist-explains-the-red-planets-dry-dusty-storms-271364

Source: The Conversation – USA – By Mahesh Nepal, Ph.D. Student in Electrical Engineering, Binghamton University, State University of New York

When your winter jacket slows heat escaping your body or the cardboard sleeve on your coffee keeps heat from reaching your hand, you’re seeing insulation in action. In both cases, the idea is the same: keep heat from flowing where you don’t want it. But this physics principle isn’t limited to heat.

Electronics use it too, but with electricity. An electrical insulator stops current from flowing where it shouldn’t. That’s why power cords are wrapped in plastic. The plastic keeps electricity in the wire, not in your hand.

Inside electronics, insulators do more than keep the user safe. They also help devices store charge in a controlled way. In that role, engineers often call them dielectrics. These insulating layers sit at the heart of capacitors and transistors. A capacitor is a charge-storing component – think of it as a tiny battery, albeit one that fills up and empties much faster than a battery. A transistor is a tiny electrical switch. It can turn current on or off, or control how much current flows.

Together, capacitors and transistors make modern electronics work. They help phones store information, and they help computers process it. They help today’s AI hardware move huge amounts of data at high speed.

What surprises most people is how thin these insulating, current-quelling dielectrics are. In modern microchips, key dielectric layers can be only a few nanometers thick. That’s tens of thousands of times thinner than a human hair. A modern phone can contain billions of transistors, so at that scale, slimming them down by even 1 nanometer can make a difference.

As an electrical and material scientist, I work with my adviser, Tara P. Dhakal, at Binghamton University to understand how to make these insulating layers as thin as possible while preserving their reliability.

Thinner dielectrics don’t just shrink devices. They can also help store more charge. But at such scale, electronics get finicky. Sometimes what looks like a breakthrough isn’t quite what it seems. That’s why our focus is not just making dielectrics thin. It’s making them both thin and trustworthy.

What makes one dielectric better than another?

In both capacitors and transistors, the basic structure is simple: They contain two conductors separated by a thin insulator. If you bring the conductors closer, more charge can build up. It’s like two strong magnets with a sheet between them – the thinner the sheet, the stronger the pull.

But thinning has a limit. In transistors, the classic insulator silicon dioxide loses its ability to insulate at about 1.2 nanometers. At that scale, electrons can sneak through a shortcut called quantum tunneling. Enough charge leaks through that the device is no longer practical.

When materials are so thin that they start to leak, engineers have another lever. They can switch to an insulator that stores more charge without being made extremely thin. That ability is described by a metric called the dielectric constant, written as k. Higher-k materials can achieve that storage with a thicker layer, which makes it much harder for electrons to slip through.

For example, silicon dioxide has k of about 3.9, and aluminum oxide has k of about 8, twice as high. If a 1.2-nanometer silicon dioxide layer leaks too much, you can switch to a 2.4-nanometer aluminum oxide layer and get roughly the same charge storage. Because the film is physically thicker, it won’t leak as much.

The breakthrough that wasn’t

In 2010, a team of researchers at Argonne National Laboratory reported something that sounded almost impossible: They’d made an ultrathin coating that apparently had a giant dielectric constant, near 1,000. The material wasn’t a single new compound. It was a nanolaminate – a microscopic layer cake. In nanolaminates, you stack two materials in repeating A-B-A-B layers, hoping their interfaces create properties neither material has on its own.

In that work, the stack alternated aluminum oxide, with a k of about 8, and titanium oxide, with a k of about 40. The researchers built the stack by growing one molecular layer at a time, which is ideal for building and controlling the nanometer-scale layers in a nanolaminate.

When the team made each sublayer less than a nanometer, it found that the entire material was able to hold an incredible amount of charge – thus, the giant k.

The result triggered years of follow-up work and similar reports in other stacks of oxides.

But there’s a twist. In our recent study of the aluminum oxide/titanium oxide nanolaminate system, we found that the apparent giant k value was a measurement error.

In our study, the nanolaminate wasn’t acting like a clean insulator, and it was leaking enough to inflate the k value. Think of a bucket with a hairline crack: You keep pouring, and it seems like the bucket holds a lot, even though the water won’t stay inside.

Once we figured that a leak was behind the giant k result, we set out to solve the larger puzzle. We wanted to know what makes the nanolaminate leak, and what process change could make it truly insulating.

The culprit

We first looked for an obvious culprit: a visible defect. If a film stack leaks, you expect pinholes or cracks. But the nanolaminate looked smooth and continuous under the microscope. So why would a stack that looks solid fail?

The answer wasn’t in the shape, it was in the chemistry. The earliest aluminum oxide sublayers didn’t contain enough aluminum. That meant the film looked continuous, yet was still incomplete at the atomic scale. Electrons could find connected paths and escape through it. It was physically continuous but electrically leaky.

Our process to create these films, called atomic layer deposition, uses tiny, repeatable cycles. You add in two chemicals, one after the other. Each pair is one cycle. For aluminum oxide, the pair is often trimethylaluminium (TMA), which is the aluminum source, and water, which is the oxygen source. Together, they create the aluminum oxide, and one cycle adds roughly a single layer of material – about one-tenth of a nanometer. By repeating the cycles, you can grow the film to the thickness you need: about 10 cycles for 1 nanometer, 25 cycles for 2.5 nanometers, and so on.

But there’s a catch. When you deposit aluminum oxide on top of titanium oxide, the first chemical for aluminum oxide – TMA – can steal oxygen from the titanium oxide layer below. This issue removes some of the sites the aluminum source normally reacts with on the layer’s surface. So, the first aluminum oxide layer doesn’t grow evenly and ends up with less aluminum than it should have.

That problem leaves tiny weak spots where electrons can slip through and cause leakage. Once the aluminum oxide becomes thick enough – around 2 nanometers – it forms a more complete barrier, and those leakage paths are effectively sealed off.

One small change flipped the outcome. We kept the same aluminum source, TMA, but swapped the oxygen source. Instead of water, we used ozone. Ozone is a stronger oxygen source, so it can replace oxygen that gets pulled out during the TMA step. That shut down leakage paths. The aluminum oxide then behaved like a real barrier, even when it was thinner than a nanometer. With the ozone fix, the nanolaminate acted like a true insulator.

The takeaway is simple: When you’re down to a few atomic layers, chemistry can matter as much as thickness. The types of chemical compounds you use can decide whether those early layers become a real barrier or leave behind leakage paths.

Mahesh Nepal does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. An ultrathin coating for electronics looked like a miracle insulator − but a hidden leak fooled researchers for over a decade – https://theconversation.com/an-ultrathin-coating-for-electronics-looked-like-a-miracle-insulator-but-a-hidden-leak-fooled-researchers-for-over-a-decade-272009