Category: English

Source: The Conversation – USA (2) – By Bethany Bradley, Professor of Biogeography and Spatial Ecology, UMass Amherst

When the Trump administration began freezing federal funding for climate and ecosystem research, one of the programs hit hard was ours: the U.S. Geological Survey’s Climate Adaptation Science Centers.

These nine regional centers help fish, wildlife, water, land – and, importantly, people – adapt to rising global temperatures and other climate shifts.

The centers have been helping to track invasive species, protect water supplies and make agriculture more sustainable in the face of increasing drought conditions. They’re improving wildfire forecasting, protecting shorelines and saving Alaska salmon, among many other projects.

All of this work happens through partnerships: Scientists, many of them affiliated with universities, team up with public and private resource managers – the people who manage water supplies, wildlands, recreation areas, shorelines and other natural resources – to develop the research and solutions those managers need.

But in spring 2025, after 15 years of operation of the centers, the president’s proposed federal budget zeroed out funding for them. Federal workers at the centers were threatened with layoffs.

Three of the nine regional centers – covering the South Central, Pacific Islands and Northeast regions – were left unfunded when the Office of Management and Budget withheld and then blocked funds Congress had already appropriated.

In spite of these challenges, we have hope that the work will eventually continue. Congress’ proposed budgets in both the U.S. House and Senate recommend fully funding the Climate Adaptation Science Centers, and there’s a reason: Natural resources managers and the public have consistently told their elected officials that the work is important.

Here are three examples of projects in regions where funding has been blocked that show why resource managers are speaking up.

Sustainable water supplies in arid lands

In south-central Texas, the Edwards Aquifer Authority is responsible for providing sustained water resources for 2.5 million people in cities such as San Antonio and Uvalde. It also maintains the groundwater-fed springs that support threatened and endangered species.

In recent decades, however, both heavy rainfall and prolonged, intense droughts have increased uncertainty about how much water will be available from the aquifer.

At the South Central Climate Adaptation Science Center, researchers from the University of Oklahoma teamed up with the aquifer authority to develop high-resolution climate projections for assessing future changes to groundwater recharge and ecologically sensitive springs.

The climate projections are helping the authority determine whether its existing drought-mitigation practices are effective for sustaining freshwater springs and groundwater levels.

Losing funding for the Climate Adaptation Science Center means this technical guidance for water management and many other projects in the region are no longer available.

Stalled science doesn’t just hurt Texas. Many arid and semi-arid regions of the U.S. rely on aquifers to provide water supplies for homes, businesses and agriculture, and they need this type of research to maintain water security.

Solutions for agriculture and fire protection

On the Hawaiian island of O’ahu, up to 40% of agricultural land is unmanaged and unplanted pasture that is often invaded by non-native grasses. These grasses increase fire risk as the islands face more intense and longer-lasting droughts.

The Pacific Islands Climate Adaptation Science Center has been working on a solution to help restore fallow lands through agroforestry, in which farmers grow crops among trees, mirroring Indigenous practices.

Climate Adaptation Science Center researchers at the University of Hawai’i Mānoa partnered with Kākoʻo ʻŌiwi, a nonprofit organization that is restoring Indigenous food systems, to identify lands that will remain suitable for agroforestry even under worsening drought caused by climate change. The research has shown how management practices can increase soil health and increase the soil’s carbon storage.

Since 2019, researchers have taught hundreds of volunteers from the community and student groups about restoration practices that include food production, forest conservation and climate resilience.

Lost funding for Climate Adaptation Science Centers put the brakes on science that supports local communities.

Managing invasive species in a warming world

Invasive species cost the U.S. economy an estimated US$10 billion a year in damage to crops, forests and ecosystems. At the same time, climate change is increasing the range of many invasive species and making them harder to control.

In 2016, researchers from the Northeast Climate Adaptation Science Center at the University of Massachusetts Amherst learned that resource managers were concerned about how climate change would affect invasive species ranges. To understand and address the needs of resource managers, Climate Adaptation Science Center researchers created the Regional Invasive Species and Climate Change Network, which has become a primary source for mapping invasive species’ movement and sharing invasive species research across the region.

Climate Adaptation Science Center researchers conducted a series of projects to identify invasive plants expanding into northern and southern New England and mid-Atlantic states. The results have helped the state of Massachusetts update its invasive plant risk assessment and expanded regulators’ lists of invasive species to prohibit from sales in New York and Maine.

States recently asked the center’s researchers to develop a database of current and emerging invasive plants across the Northeast to help them build consistent and proactive defenses against emerging invasive species. Stalled funding has also stalled this project.

These are the kind of real-world solutions that federal funding cuts are stopping. When that work disappears, it leaves America and Americans more vulnerable to climate change.

Bethany Bradley receives funding from the US Geological Survey as the University Director of the Northeast Climate Adaptation Science Center.

Adrienne Wootten previously received funding from the US Geological Survey for research projects through the South Central Climate Adaptation Science Center and is currently engaged in research with the Edwards Aquifer Authority.

Ryan Longman receives funding from the US Geological Survey as the University Director of the Pacific Islands Climate Adaptation Science Center

– ref. From invasive species tracking to water security – what’s lost with federal funding cuts at US Climate Adaptation Science Centers – https://theconversation.com/from-invasive-species-tracking-to-water-security-whats-lost-with-federal-funding-cuts-at-us-climate-adaptation-science-centers-269908

Source: The Conversation – USA (2) – By Katherine Fink, Associate Professor of Media, Communications, and Visual Arts, Pace University

Although advertising revenue largely sustained the news media in the 20th century, it’s been harder to come by in the digital age. News media outlets just aren’t as important these days for advertisers when they can reach potential customers so many other ways, including through social media.

Some news outlets are relying more on subscription revenue. But that can also be a tough sell when readers have so many alternatives – often free – for finding news, if they’re even looking for it at all.

Increasingly, local news media outlets are adopting nonprofit models to be able to obtain grants from foundations and donations from individuals as new revenue sources.

At the same time, some nonprofit news leaders have avoided selling ads because the IRS has said their organizations would have to pay taxes on that revenue. They have also heard that selling too many ads might jeopardize their tax-exempt status altogether.

My research suggests that they need not worry about that – although, given recent threats by the Trump administration against Harvard University and other nonprofits, they may have reasons to be wary.

Encouraging earned revenue

I’m a former public radio journalist who now researches the nonprofit news sector.

I interviewed 23 nonprofit news leaders in 2023 about their fundraising practices. I also reviewed hundreds of 990 forms that most nonprofits are required to file annually with the IRS.

In early 2025, I published a study that found most nonprofit news leaders still depended heavily on foundations and individual donors. That’s despite calls from foundations and the Institute for Nonprofit News, an organization representing these media outlets, that they should diversify their revenue sources.

The Institute for Nonprofit News especially encourages news nonprofits to consider adding earned revenue. That category can include lots of things, but most often it means selling ads. The nonprofit news leaders I spoke with had mixed feelings about that.

Taxing unrelated business income

The philanthropic dollars that charitable nonprofits get from foundations, individual donors and corporations are exempt from taxes. But their earned revenue from sources such as advertising, sponsorships or ticketed events is often taxable.

That’s because U.S. tax law requires nonprofits to pay taxes on income deemed to be “not substantially related” to their public service missions.

Take, for example, money that a nonprofit museum earns through its gift shop. The government taxes that as unrelated business income so nonprofits don’t get an unfair edge over their for-profit competitors.

Money raised through ad sales has also historically counted as unrelated business income for nonprofits, according to the IRS. Some nonprofit news leaders say that’s not how it should be.

Some news nonprofits are directly challenging the traditional classification of advertising revenue as unrelated business income.

For example, the San Antonio Report, a nonprofit news outlet, reported receiving US$361,649 in advertising revenue in tax year 2022. But the organization did not pay taxes on it, because it identifies advertising as part of its mission. In fact, a Supreme Court ruling in the 1986 United States v. American College of Physicians case left open the possibility that advertising could be a tax-exempt form of revenue if it had an “educational function” related to the nonprofit’s purpose.

Selling ads anyway

Nonprofit news leaders not trying to challenge that classification still had reason to be concerned about running paid ads.

The IRS has warned it could revoke the tax-exempt status of nonprofits that had too much unrelated business income in their portfolios. That’s one of the top six reasons organizations lose their nonprofit status, according to the IRS. Other reasons include failure to serve an exempt purpose, lobbying, political campaigning, mission drift and failure to complete annual 990 forms.

How much unrelated business income is too much? The IRS has not provided clear guidance on this, despite pleas from local nonprofit news advocates.

One editor I interviewed, whose free weekly newspaper had recently converted from a for-profit enterprise to a nonprofit, lamented that her copious ad portfolio could put her tax-exempt status in jeopardy. Ads had always been part of what readers appreciated about her newspaper, she said – it was how they learned about restaurants and nightlife.

Some tax advisers recommend that nonprofits keep unrelated business income below 25% of their total revenue. But the ambiguity is enough to make some nonprofit news leaders prefer to not get any at all.

Some local news nonprofits are selling ads, despite their reservations about the potential tax impact and the potential threat of the IRS revoking their tax-exempt status. Of the Institute for Nonprofit News’ roughly 201 local newsroom members, 21 reported earning at least $1,000 in unrelated business income in the most recent year for which data was available when I conducted these interviews – usually 2022 or 2023. That happens to be the minimum reportable amount.

Paying no taxes

Only three of these 21 local news nonprofits paid taxes on their advertising revenue – and the ones that paid did so at reduced amounts. The outlets were largely able to avoid taxes due to exemptions the IRS allows nonprofits to claim for advertising-related expenses, such as commissions, agency fees and production. Several news nonprofits were also able to deduct readership costs, such as printing and distribution.

Local news nonprofits also appeared not to draw the ire of the IRS for accepting too much advertising revenue. While most reported unrelated business income that amounted to less than 25% of their total revenue, five news nonprofits did exceed that percentage, sometimes by quite a bit.

Rarely revoking tax exemptions

It turns out the IRS rarely revokes the tax-exempt status of charitable nonprofits of any kind for collecting too much unrelated business income.

IRS records indicate that the most common reason for revocations was the failure of nonprofits to file their 990 forms annually.

Not doing so for three years in a row triggers an automatic revocation, which can be reversed if nonprofits get back into compliance by belatedly filing their overdue paperwork. Revocations for all other reasons, including excessive unrelated business income, have impacted less than 0.1% of nonprofits, according to my analysis of IRS records.

In other words, two common concerns about advertising expressed by the nonprofit news leaders I interviewed – the potential tax burden and the risk of running afoul of the IRS – appear to have been unfounded.

At the same time, it can be hard to keep up with what might run afoul of IRS rules.

Starting in April 2025, the Trump administration threatened to revoke the nonprofit status of Harvard University after its leaders resisted numerous demands, including changes to its leadership and admissions policies.

Nonprofit news organizations have also faced pressure from the Trump administration. Several public media outlets are planning to shut down or reduce their operations following the Corporation for Public Broadcasting’s loss of government funding in 2025. It’s part of what’s widely seen as the administration’s attempt to control news media, a campaign that has also led to defamation lawsuits, a leadership shakeup at CBS News, and the Federal Communications Commission’s deregulation efforts.

So far, Harvard’s nonprofit status remains intact, and legal experts say it’s likely to stay that way. Still, at a time when many local news nonprofits are struggling to keep the lights on, I can understand why they might choose to tread lightly.

The Conversation U.S. is a member of the Institute for Nonprofit News and does not get any revenue from advertising.

Katherine Fink 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. Nonprofit news outlets are often scared that selling ads could jeopardize their tax-exempt status, but IRS records show that’s been rare – https://theconversation.com/nonprofit-news-outlets-are-often-scared-that-selling-ads-could-jeopardize-their-tax-exempt-status-but-irs-records-show-thats-been-rare-268844

Source: The Conversation – USA (3) – By Daniel P. Aldrich, Professor of Political Science, Public Policy and Urban Affairs, Northeastern University

Social isolation kills. It increases your risk of death by 30% — roughly the same as smoking cigarettes and much worse than factors such as obesity and sedentary living.

Americans are living through what researchers call a friendship recession, spending less time with friends than at any point in recent history.

In 2023, the U.S. Surgeon General declared loneliness an epidemic. Deaths from factors like suicide, addiction and alcoholism, referred to as deaths of despair, continue climbing.

While doctors routinely check patients’ blood pressure and ask about exercise habits, they rarely assess social health.

Public health guidelines urge Americans to eat their vegetables, exercise for 150 minutes weekly, sleep seven to nine hours nightly and drink less than one or two alcoholic beverages per day. But few public health bodies have addressed social connection — until now.

As scholars who focus on public policy and social determinants of health and well-being, we are part of an international team of more than 100 experts who undertook the first systematic effort to develop evidence-based guidelines for social connection.

These guidelines, which are now publicly available, aim to do more than offer advice. Elements of them are already being embedded into policies in the Netherlands and the U.K.

Our hope is that the guidelines can elevate the importance of social connection to the same level as basic public health practices such as exercising, not smoking and relying on a designated driver when you go out drinking with friends.

The value of guidelines

Research has shown for decades that social connection is crucial for good health. The World Health Organization’s constitution, adopted in 1946, defines health as “complete physical, mental and social well-being.”

Codifying different dimensions of health into evidence-based guidelines matters because guidelines allow people to put recommendations into action. Nutrition labels help people understand what they’re eating. Exercise recommendations help people know how much movement protects their health. Blood pressure cutoffs tell both patients and clinicians when it’s time to intervene.

Guidelines also shape systems in ways people feel every day. Exercise guidelines, for example, helped motivate cities to invest in walkable streets and bike lanes, workplaces to design wellness programs, and schools to include physical activity in curricula.

Social health guidelines can play a similar role.

Standardized metrics for social well-being can help health care providers identify when someone is socially isolated, enable employers to design workplaces that foster connection, and give schools and cities clearer targets for building socially supportive environments.

They also lay the groundwork for “social prescriptions” — structured ways to connect people with community programs or group activities — which some health care systems are already beginning to test.

The science of connection

Beginning in the summer of 2023, our team spent more than two years developing a set of international guidelines for social health by drawing on more than 40 plain-language evidence summaries, numerous case studies, conversations with marginalized communities, and extensive consultation with global experts.

What we found highlights several foundational principles of social well-being.

First, there are no universal rules for social health. There is no magic number of friends or ideal number of weekly social hours. Social needs vary widely. Both introverts and extroverts need connection, but they meet that need differently. A new parent’s social world is completely unlike a retiree’s. And quality trumps quantity: One meaningful conversation can be more nourishing than a dozen quick exchanges.

Second, technology is not the villain it’s often made out to be. Passive scrolling can harm well-being, but active, intentional use can strengthen bonds — whether through video calls with distant family, group chats that sustain friendships or apps that help neighbors organize local meetups. The key is using technology to facilitate real connection rather than replace it.

Third, relationships are shaped as much by systems as by individuals. Social health isn’t just about personal effort. It emerges from local environments that make connection possible. Research shows that investments in social infrastructure – the places and spaces where we connect, such as libraries, parks and cafes – measurably improve well-being. And communities that have denser concentrations of such spaces have better health outcomes after disasters.

Finally, diverse networks matter. Strong social health includes both close relationships and “weak ties” — acquaintances, neighbors, local business staff and others you see in passing. These lighter-touch interactions offer meaningful benefits: the barista who remembers your order, a colleague you exchange a few words with, a fellow dog walker along your route.

Studies show that weak ties provide novel information, unexpected opportunities and a broader sense of belonging that close friends alone can’t provide. A mix of ties — deep and shallow — forms the basis of a socially healthy life.

From research to reality

Forward-thinking institutions are already experimenting with principles that underpin our guidelines.

Some workplaces now assess social health when making decisions about policies such as remote work or office layout, recognizing that communication norms and physical design shape how employees connect. Schools are teaching emotional intelligence and friendship skills as core curriculum, not extras. Cities are investing in social infrastructure — community centers, shared public spaces and plazas — that naturally bring people together.

On a personal level, the guidelines suggest a few simple shifts:

• Prioritize face-to-face time. Even short, in-person interactions boost mood, reduce stress and build trust.

• Use technology actively, not passively. Reach out to someone, schedule a video call or use apps to create opportunities for connection — not just to scroll.

• Treat solitude as restoration, not failure. Healthy social lives include both meaningful interaction and the downtime needed to recharge.

• Build routines that create natural interaction. Walk the same route daily, become a regular at neighborhood spots or join recurring community activities to create predictable opportunities for connection.

• And most importantly, take initiative. In a culture that treats socializing as a luxury, prioritizing connection is quietly radical.

Kiffer George Card receives funding from the Social Sciences and Humanities Research Council, The Canadian Institutes of Health Research, and the Health Research BC. He is also an affiliate of Social Health Canada and the GenWell Project.

Daniel P. Aldrich 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. We created health guidelines for fighting loneliness – here’s what we recommend – https://theconversation.com/we-created-health-guidelines-for-fighting-loneliness-heres-what-we-recommend-268560

Source: The Conversation – USA – By Amy Wrobleski, Ph.D. Candidate in Ecology and Anthropology, Penn State

Like many mushroom harvesters, I got interested in foraging for fungi during the COVID-19 pandemic.

I had been preparing for a summer of field work studying foraged desert plants in a remote part of Australia when the pandemic hit, and my travel plans were abruptly frozen. It was March, right before morel mushrooms emerge in central Pennsylvania.

I wasn’t doing a lot other than going on long hikes and taking classes remotely at Penn State for my doctoral degree in ecology and anthropology. One of the classes was an agroforestry class with Eric Burkhart. We studied how agriculture and forests benefit people and the environment.

These two things eventually led to a yearslong project on mushroom harvesting in our region.

Why people forage

Foragers have been harvesting wild mushrooms in what is now Pennsylvania and the rest of the U.S. mid-Atlantic region for generations, but the extent and specifics of the practice in the region had not been formally studied.

In 2021, Burkhart and I decided that we wanted to better understand the variety of wild mushroom species that Pennsylvania harvesters collect and what they use them for.

We conducted a series of surveys in 2022 and 2023 that revealed a wide variety of fungi are foraged in the region – though morels, chicken of the woods and chanterelles are most common. We also learned that harvesters use the mushrooms primarily for food and medicinal purposes, and that foragers create communities that share knowledge. These community based projects often use social media tools as a way for mushroom harvesters to share pictures, notes and even the results of DNA sequences.

Our findings were published in the journal Economic Botany in October 2025.

160 species

Having spent a year building connections with local mushroom harvesters, starting in central Pennsylvania, including members of mushroom clubs and mycological associations, we recruited a diverse group of harvesters from around the mid-Atlantic. We also used mushroom festivals, social media and word of mouth to get the word out.

We asked harvesters about their favorite mushrooms, common harvesting practices, resources they used while harvesting and any sustainability practices.

Over 800 harvesters responded to the survey and reported that, collectively, they foraged 160 species of wild mushrooms. Morels and chicken of the woods were the two most popular, as each were reported by 13% of respondents. About 10% of respondents reported collecting chanterelles. Other popular species were hen of the woods, oysters, lion’s mane, black trumpet, honey mushroom, turkey tail, bolete, reishi, puffball, chaga, shrimp of the woods and Dryad’s saddle, which is also known as the pheasant’s back mushroom.

Harvesters reported a variety of reasons for collecting mushrooms. Many collected morels and chanterelle to eat, and species such as turkey tail, reishi and chaga for medicinal purposes. Art was another common reason cited for foraging, with photography being the most popular use, followed by using mushrooms to create natural dyes and pigments.

Other survey respondents said they foraged to feel more connected to nature. And while there is a thriving commercial wild mushroom industry in the region, we found that only a small minority of harvesters sell their mushrooms. Most people reported giving their mushrooms to friends, neighbors and family.

Citizen science

We also wanted to better understand which resources mushroom harvesters turn to in order to learn more about this hobby. We asked all the harvesters what they used as a resource when they were first learning to hunt for mushrooms. A quarter of new harvesters said they used the “the internet,” followed by “family,” at 24%, and then guide books, at 20%.

Based on the survey responses, we also learned that mushroom-identification phone apps are growing in popularity, especially among new harvesters. For example, a commonly used app called iNaturalist allows harvesters to upload a few pictures of their find – one of the mushroom in its habitat, another of the underside of the cap, and a third of the entire mushroom. From there, other community members can comment and help with identification.

Harvesters also use these apps to contribute to community science projects that document biodiversity.

Some mushrooms are poisonous if eaten, which is part of why harvesters are so careful with their identification. When learning a new mushroom species, it’s important to look into multiple sources to make sure what you’re harvesting is safe to eat.

With more harvesters documenting their findings on social media and sharing information about fungal biodiversity in the region, there is much to glean and learn about the diverse world of mushrooms in the mid-Atlantic. We believe that deeper collaboration between community groups and researchers at universities and other institutions is an opportunity for scientific growth within the field of mycology. This collaboration can support long-term tracking of fungal populations and any impact that harvesters might have on them.

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

Amy Wrobleski receives funding from the Mycological Association of Washington DC.

Eric Burkhart 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. Mid-Atlantic mushroom foragers collect 160 species for food, medicine, art and science – https://theconversation.com/mid-atlantic-mushroom-foragers-collect-160-species-for-food-medicine-art-and-science-268143

Source: The Conversation – USA – By Stephen DiKerby, Postdoctoral Researcher in Physics and Astronomy, Michigan State University

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.

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How will the universe end? – Iez M., age 9, Rochester, New York

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Whether the universe will “end” at all is not certain, but all evidence suggests it will continue being humanity’s cosmic home for a very, very long time.

The universe – all of space and time, and all matter and energy – began about 14 billion years ago in a rapid expansion called the Big Bang, but since then it has been in a state of continuous change. First, it was full of a diffuse gas of the particles that now make up atoms: protons, neutrons and electrons. Then, that gas collapsed into stars and galaxies.

Our understanding of the future of the universe is informed by the objects and processes we observe today. As an astrophysicist, I observe objects like distant galaxies, which lets me study how stars and galaxies change over time. By doing so, I develop theories that predict how the universe will change in the future.

Predicting the future by studying the past?

Predicting the future of the universe by extending what we see today is extrapolation. It’s risky, because something unexpected could happen.

Interpolation – connecting the dots within a dataset – is much safer. Imagine you have a picture of yourself when you were 5 years old, and then another when you were 7 years old. Someone could probably guess what you looked like when you were 6. That’s interpolation.

Maybe they could extrapolate from the two pictures to what you’d look like when you are 8 or 9 years old, but no one can accurately predict too far into the future. Maybe in a few years you get glasses or suddenly get really tall.

Scientists can predict what the universe will probably look like a few billion years into the future by extrapolating how stars and galaxies change over time, but eventually things could get weird. The universe and the stuff within might once again change, like it has in the past.

How will stars change in the future?

Good news: The Sun, our medium-sized yellow star, is going to continue shining for billions of years. It’s about halfway through its 10 billion-year lifetime. The lifetime of a star depends on its size. Big, hot, blue stars live shorter lives, while tiny, cool, red stars live for much longer.

Today, some galaxies are still producing new stars, but others have depleted their star-forming gas. When a galaxy stops forming stars, the blue stars quickly go “supernova” and disappear, exploding after only a few million years. Then, billions of years later, the yellow stars like the Sun eject their outer layers into a nebula, leaving only the red stars puttering along. Eventually, all galaxies throughout the universe will stop producing new stars, and the starlight filling the universe will gradually redden and dim.

In trillions of years – hundreds of times longer than the universe’s current age – these red stars will also fade away into darkness. But until then, there will be lots of stars providing light and warmth.

How will galaxies change in the future?

Think of building a sand castle on the beach. Each bucket of sand makes the castle bigger and bigger. Galaxies grow over time in a similar way by eating up smaller galaxies. These galactic mergers will continue into the future.

In galaxy clusters, hundreds of galaxies fall inward toward their shared center, often resulting in messy collisions. In these mergers, spiral galaxies, which are orderly disks, combine in chaotic ways into disordered blob-shaped clouds of stars. Think of how easy it is to turn a well-constructed sand castle into a big mess by kicking it over.

For this reason, the universe over time will have fewer spiral galaxies and more elliptical galaxies because the spiral galaxies combine into elliptical galaxies.

The Milky Way galaxy and the neighboring Andromeda galaxy might combine in this way in a few billion years. Don’t worry: The stars in each galaxy would whiz past each other totally unharmed, and future stargazers would get a fantastic view of the two galaxies merging.

How will the universe itself change in the future?

The Big Bang kick-started an expansion that probably will continue in the future. The gravity of all the stuff in the universe – stars, galaxies, gas, dark matter – pulls inward and slows down the expansion, and some theories suggest that the universe’s expansion will coast along or slow to a halt.

However, some evidence suggests that some unknown force is starting to exert a repulsive force, causing expansion to speed up. Scientists call this outward force dark energy, but very little is known about it. Like raisins in a baking cookie, galaxies will zoom away from each other faster and faster. If this continues into the future, other galaxies might be too far apart to observe from the Milky Way.

To summarize the best current prediction of the future: Star formation will shut down, so galaxies will be full of old, red, dim stars gradually cooling into darkness. Each group or cluster of galaxies will merge into a single, massive, elliptical galaxy. The accelerated expansion of the universe will make it impossible to observe other galaxies beyond the local group.

This scenario eventually winds down into a dark eternity, lasting trillions of years. New data might come to light that changes this story, and the next stage in the universe’s history might be something totally different and unexpectedly beautiful. Depending on how you look at it, the universe might not have an “end,” after all. Even if what exists is very different from how the universe is now, it’s hard to envision a distant future where the universe is entirely gone.

How does this scenario make you feel? It sometimes makes me feel wistful, which is a type of sadness, but then I remember we live at a very exciting time in the story of the universe: right at the start, in an era full of exciting stars and galaxies to observe! The cosmos can support human society and curiosity for billions of years into the future, so there’s lots of time to keep exploring and searching for answers.

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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.

Stephen DiKerby receives funding from the National Science Foundation.

– ref. How will the universe end? – https://theconversation.com/how-will-the-universe-end-269678

Source: The Conversation – USA – By Marcos Fernandez Tous, Assistant Professor of Space Studies, University of North Dakota

Every year, companies and space agencies launch hundreds of rockets into space – and that number is set to grow dramatically with ambitious missions to the Moon, Mars and beyond. But these dreams hinge on one critical challenge: propulsion – the methods used to push rockets and spacecraft forward.

To make interplanetary travel faster, safer and more efficient, scientists need breakthroughs in propulsion technology. Artificial intelligence is one type of technology that has begun to provide some of these necessary breakthroughs.

We’re a team of engineers and graduate students who are studying how AI in general, and a subset of AI called machine learning in particular, can transform spacecraft propulsion. From optimizing nuclear thermal engines to managing complex plasma confinement in fusion systems, AI is reshaping propulsion design and operations. It is quickly becoming an indispensable partner in humankind’s journey to the stars.

Machine learning and reinforcement learning

Machine learning is a branch of AI that identifies patterns in data that it has not explicitly been trained on. It is a vast field with its own branches, with a lot of applications. Each branch emulates intelligence in different ways: by recognizing patterns, parsing and generating language, or learning from experience. This last subset in particular, commonly known as reinforcement learning, teaches machines to perform their tasks by rating their performance, enabling them to continuously improve through experience.

As a simple example, imagine a chess player. The player does not calculate every move but rather recognizes patterns from playing a thousand matches. Reinforcement learning creates similar intuitive expertise in machines and systems, but at a computational speed and scale impossible for humans. It learns through experiences and iterations by observing its environment. These observations allows the machine to correctly interpret each outcome and deploy the best strategies for the system to reach its goal.

Reinforcement learning can improve human understanding of deeply complex systems – those that challenge the limits of human intuition. It can help determine the most efficient trajectory for a spacecraft heading anywhere in space, and it does so by optimizing the propulsion necessary to send the craft there. It can also potentially design better propulsion systems, from selecting the best materials to coming up with configurations that transfer heat between parts in the engine more efficiently.

Reinforcement learning for propulsion systems

In regard to space propulsion, reinforcement learning generally falls into two categories: those that assist during the design phase – when engineers define mission needs and system capabilities – and those that support real-time operation once the spacecraft is in flight.

Among the most exotic and promising propulsion concepts is nuclear propulsion, which harnesses the same forces that power atomic bombs and fuel the Sun: nuclear fission and nuclear fusion.

Fission works by splitting heavy atoms such as uranium or plutonium to release energy – a principle used in most terrestrial nuclear reactors. Fusion, on the other hand, merges lighter atoms such as hydrogen to produce even more energy, though it requires far more extreme conditions to initiate.

Fission is a more mature technology that has been tested in some space propulsion prototypes. It has even been used in space in the form of radioisotope thermoelectric generators, like those that powered the Voyager probes. But fusion remains a tantalizing frontier.

Nuclear thermal propulsion could one day take spacecraft to Mars and beyond at a lower cost than that of simply burning fuel. It would get a craft there faster than electric propulsion, which uses a heated gas made of charged particles called plasma.

Unlike these systems, nuclear propulsion relies on heat generated from atomic reactions. That heat is transferred to a propellant, typically hydrogen, which expands and exits through a nozzle to produce thrust and shoot the craft forward.

So how can reinforcement learning help engineers develop and operate these powerful technologies? Let’s begin with design.

Reinforcement learning’s role in design

Early nuclear thermal propulsion designs from the 1960s, such as those in NASA’s NERVA program, used solid uranium fuel molded into prism-shaped blocks. Since then, engineers have explored alternative configurations – from beds of ceramic pebbles to grooved rings with intricate channels.

Why has there been so much experimentation? Because the more efficiently a reactor can transfer heat from the fuel to the hydrogen, the more thrust it generates.

This area is where reinforcement learning has proved to be essential. Optimizing the geometry and heat flow between fuel and propellant is a complex problem, involving countless variables – from the material properties to the amount of hydrogen that flows across the reactor at any given moment. Reinforcement learning can analyze these design variations and identify configurations that maximize heat transfer. Imagine it as a smart thermostat but for a rocket engine – one you definitely don’t want to stand too close to, given the extreme temperatures involved.

Reinforcement learning and fusion technology

Reinforcement learning also plays a key role in developing nuclear fusion technology. Large-scale experiments such as the JT-60SA tokamak in Japan are pushing the boundaries of fusion energy, but their massive size makes them impractical for spaceflight. That’s why researchers are exploring compact designs such as polywells. These exotic devices look like hollow cubes, about a few inches across, and they confine plasma in magnetic fields to create the conditions necessary for fusion.

Controlling magnetic fields within a polywell is no small feat. The magnetic fields must be strong enough to keep hydrogen atoms bouncing around until they fuse – a process that demands immense energy to start but can become self-sustaining once underway. Overcoming this challenge is necessary for scaling this technology for nuclear thermal propulsion.

Reinforcement learning and energy generation

However, reinforcement learning’s role doesn’t end with design. It can help manage fuel consumption – a critical task for missions that must adapt on the fly. In today’s space industry, there’s growing interest in spacecraft that can serve different roles depending on the mission’s needs and how they adapt to priority changes through time.

Military applications, for instance, must respond rapidly to shifting geopolitical scenarios. An example of a technology adapted to fast changes is Lockheed Martin’s LM400 satellite, which has varied capabilities such as missile warning or remote sensing.

But this flexibility introduces uncertainty. How much fuel will a mission require? And when will it need it? Reinforcement learning can help with these calculations.

From bicycles to rockets, learning through experience – whether human or machine – is shaping the future of space exploration. As scientists push the boundaries of propulsion and intelligence, AI is playing a growing role in space travel. It may help scientists explore within and beyond our solar system and open the gates for new discoveries.

Sreejith Vidhyadharan Nair receives funding from the University of North Dakota. I have previously received external research funding from agencies such as the FAA and NASA; however, these projects were not related to nuclear propulsion systems.

Marcos Fernandez Tous, Preeti Nair, and Sai Susmitha Guddanti do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

– ref. AI is making spacecraft propulsion more efficient – and could even lead to nuclear-powered rockets – https://theconversation.com/ai-is-making-spacecraft-propulsion-more-efficient-and-could-even-lead-to-nuclear-powered-rockets-268643