100 years ago, the Social Gospel movement pushed to improve workers’ lives – but also to promote its vision of Christian America

Source: The Conversation – USA (3) – By Christina Littlefield, Associate Professor of Communication and Religion, Pepperdine University

Immigrant children from Central Europe at a settlement house in St. Louis. Thomasa.nagel/Wikimedia Commons

President Donald Trump has praised the Gilded Age, which he believes was a time of immense national prosperity thanks to tariffs, no income tax, and few regulations on business.

Similar to today, the late 19th century was a time where a small group of men enjoyed immense wealth, privilege and power to shape the nation. It was a time of immense inequality, as factory and housing conditions crushed the lives of the poor.

And it was a time of white Christian nationalism.

In Northern cities, reformers saw the wealth gap, the plight of workers and the squalid conditions in tenements as undermining their vision of a Christian America. Fueled by faith, the Social Gospel movement worked to expand labor rights and improve living conditions at the turn of the 20th century.

At the same time, many of these white Protestant activists believed their own culture and race to be superior, and this prejudice hindered their efforts. They often spouted anti-Catholic and anti-immigrant rhetoric, and mostly ignored Black workers’ plight.

A black-and-white photo shows a man, woman and two children in a very simple room with dirty walls and almost no furniture.
One of Jacob Riis’ many photographs of living conditions on New York’s Lower East Side.
Bettmann via Getty Images

Ever since the Puritans landed, white Christian nationalism has informed how many Protestants try to shape their country – a history I trace with church historian Richard T. Hughes in the book “Christian America and the Kingdom of God.” But Christian nationalism has taken dramatically different forms over time. The progressive Social Gospellers of a century ago are a particularly striking contrast to the conservative Christian right that has shaped U.S. politics for half a century, up to today.

Guardians of a Christian nation

There are many differences between Christian nationalism then and now. Like many conservative Christians today, however, the Social Gospellers believed that the United States was uniquely chosen and blessed by God, and called to be a Christian nation. They saw themselves as the rightful guardians of that mission. And though the country was still overwhelmingly Protestant, they feared they were losing influence.

New research explored the history of the Bible – research that many Christians feared would undermine people’s trust in Scripture as the word of God, by emphasizing its human composition. New scientific ideas about the Earth’s creation and human evolution challenged their visions of an all-powerful, all-knowing God. Meanwhile, rapid industrialization and urbanization had created new social challenges, such as workers’ safety and living conditions, leading some to reject faith as irrelevant to their needs.

Social Gospellers wanted to vindicate Christianity and show it was still relevant to modern life. But white leaders’ vision of what a Christian America should look like conflated their Protestant faith with their race and culture.

Josiah Strong, for example, was a Congregationalist minister known for promoting factory safety. But he stoked fear of Catholic immigrants and endorsed the expansion of the U.S. as a benevolent empire. The Anglo-Saxon race “is destined to dispossess many weaker races, assimilate others, and mold the remainder,” Strong argued in his 1885 book, “Our Country.”

A black-and-white portrait of a man with a beard, looking serious, dressed in a suit and tie.
Baptist reformer Walter Rauschenbusch.
Library of Congress/Corbis/VCG via Getty Images

Another Social Gospel reformer, Northern Baptist theologian Walter Rauschenbusch, railed against unrestrained greed, political corruption, militarism and contempt between elites and the working class. But he shared the white supremacy of his age. God was favoring Germanic and Anglo-Saxon people, he claimed, to enact God’s purposes.

“Other races are as dear to God as we and he may be holding them in reserve to carry His banner when we drop it,” he wrote in an undated article. But it was part of God’s plan, he believed, for Northern Europeans to “hold the larger part of the world’s wealth and power in the hollow of their hands and the larger share of the world’s intellectual and spiritual possessions in the hollow of their heads.”

The ‘right’ kind of Christian

Though many white Protestants felt threatened by the challenges of immigration, they were still a clear majority, and they presumed that most Americans would endorse applying Christian ethics to public policy and social reform.

A black-and-white photograph shows a woman sitting outside, while rows of children sit on steps around her.
Jane Addams speaks to visitors in 1935 at Hull House, a settlement house in Chicago that she co-founded in 1889.
National Archives via Wikimedia Commons

What’s more, women gaining the right to vote in 1920 meant Social Gospel leaders expanded Protestants’ power at the ballot box. Many Social Gospel leaders embraced women’s suffrage because women were already leading supporters for their causes: For example, Frances Willard, who promoted temperance and workers’ rights; and Jane Addams, who ran a Christian “settlement house,” or community center, for the poor.

But in another sense, demographics were not on their side. The U.S. might have been a very white and Christian country, but in some Social Gospellers’ minds, the era’s waves of immigrants were not the “right” kind of Christian: Northern European and Protestant. Immigration was shifting from Great Britain, Ireland and Germany to Russia, Poland, Hungary and Italy. While Protestants far outnumbered Catholics nationally, Strong wrote that they were double the Protestant population in major cities like New York, Chicago and Philadelphia.

A black-and-white photograph of a woman in a dress and shawl, standing indoors with her young children, several of whom also wear dresses and shawls.
A Polish mother and her nine children waiting at Ellis Island.
U.S. National Park Service

Strong argued that Catholic immigrants were lazy, prone to alcoholism and criminal activity, and willing to sell their vote to corrupt city politicians. He claimed they would corrupt the morals of Anglo-Saxon Americans, and that if the Catholic population grew, it would undermine Protestants’ religious liberty.

Nativist views like these led to the National Origins Act of 1924, which restricted the number of immigrants. Quotas for each country were based on the profile of the American population in 1890 – an attempt to maintain Protestant dominance against Catholic and Jewish immigration from Southern and Eastern Europe. That distrust also kept Social Gospellers from partnering with Roman Catholic leaders on shared concern for workers.

Flourishing for all, or some?

Still, when it came to workers’ basic needs, reformers cared deeply about improving circumstances for the “least of these.” The movement was strongly influenced by the biblical parable of the sheep and the goats: verses in the Book of Matthew where Jesus promotes feeding the hungry, caring for the sick, clothing the naked and visiting those in prison.

Social Gospellers aimed to prove that Christianity could answer the social challenges caused by industrialization, urbanization and immigration. For the most part, they sought to use their privilege in ways that promoted the flourishing of all Americans, such as expanding labor rights and providing services to the poor through settlement houses.

A black-and-white photo shows several standing men and a seated boy surrounded by piles of fabric.
A photograph by Jacob Riis in a small New York City sweatshop in the 1880s.
Bettmann via Getty Images

In 1908, for example, the Federal Council of Churches adopted a 14-point statement called the “Social Creed,” affirming that churches should support reforms “to lift the crushing burdens of the poor, and to reduce the hardships and uphold the dignity of labor.” While some of the reforms they called for are taken for granted today — like one day off per week — other calls, like a living wage for all, are yet to be realized.

Over the past half-century, the modern Christian right, too, has feared that its vision for the nation is eroding. Conservative churches have seen their influence drop as more Americans move away from organized religion and reject their rejection of LGBTQ+ people.

I — along with other scholars — argue that these fears have helped fuel resurgent Christian nationalism today. Since merging with the tea party movement during the Obama administration, the Christian right has increasingly embraced an anti-immigration and anti-minority stance, fearing the loss of its own standing.

Like the Social Gospellers of a century ago, the Christian nationalists of recent decades are wary of religious and racial change in their country. Yet the movement’s priorities – often focused around its vision of families, sex and gender – are starkly more limited than the broader quality-of-life issues that Social Gospellers addressed.

Both groups desired an America rooted in biblical values. But each interpreted Scripture through its own lens, seeking to remake America in its own, white Protestant image.

The Conversation

Christina Littlefield 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. 100 years ago, the Social Gospel movement pushed to improve workers’ lives – but also to promote its vision of Christian America – https://theconversation.com/100-years-ago-the-social-gospel-movement-pushed-to-improve-workers-lives-but-also-to-promote-its-vision-of-christian-america-255216

Paper mills: the ‘cartel-like’ companies behind fraudulent scientific journals

Source: The Conversation – Indonesia – By Rizqy Amelia Zein, Lecturer in Social Psychology, Universitas Airlangga

Science and Nature, two leading science journals, have revealed a growing problem: an alarming rise in fraudulent research papers produced by shady paper mill companies. This wave of fake studies is creating a major headache for the academic world, putting the integrity of global academic research at risk.

Paper mill companies offer authorship services to researchers, academics, and students who want their names listed as an author of a scientific article published in reputable scientific journals.

By paying around €180 to €5000 (approximately US$197 – $5472), a person can have their name listed as the author of research paper, without having to painstakingly do research and write the results. No doubt, some experts refer to these paper mills as illegal and criminal organizations.

A 2023 research highlights a dramatic increase in fraudulent scientific articles traced back to paper mills. In just five years, the numbers of retractions soared jumped from 10 in 2019 to 2,099 in 2023.

Paper mills have also extremely overwhelmed major scientific journal publishers. Hindawi and Wiley, publishers of open access journals in the UK, for example, retracted around 1,200 paper mill articles in 2023. SAGE, a global publisher of books, journals and academic library resources and Elsevier, a scholarly publisher in the Netherlands also retracted hundreds of paper mill articles in 2022.

Paper mills are found operating in countries whose research policies incentivise researchers to produce as many scientific articles as possible, such as China, Russia, India and Iran.

However, their customer profile is quite diverse, from both developed and developing countries, including Indonesia, Malaysia, Germany, and the United States (US).

Based on research data and investigative journalist reports from the last five years, I summarise how these paper mills operate and how to detect them.

The paper mill playbook: tactics and oddities

1. Problematic articles

Paper mills generally manipulate the process of publishing scientific articles. These articles usually plagiarise other published articles, contain false and stolen data, or include engineered and duplicated images.

They also offer to rewrite scientific articles using generative artificial intelligence tools, such as ChatGPT and Quillbot, or to translate published articles from other languages into English.

2. A promised path to publication

In some cases, paper mills offer authorship slots before an article is accepted for publication.

In other cases, they offer authorship slots after the article is ready to be published by the journal.

Therefore, it is not uncommon for paper mills to sell authorship slots with a guarantee that the article will definitely be published. In fact, according to the conventions generally accepted in the academic community, no well-run journal can give such a guarantee.

Publishing decisions are normally made only after editors have considered the feedback from peer reviewers. This means, there is no possibility for a manuscript to secure acceptance before passing the peer review process.

3. Fake reviews and corrupt deals

Paper mills also offer a wide range of additional services. For example, they offer fake peer review services to convince potential buyers that the offered articles have passed rigorous review.

To smooth the way for their operations, some paper mills even operate like a cartel, bribing rogue journal editors to ensure publication. A 2024 investigation by a Science journalist revealed that some scientific journal editors were offered as much as $20,000 to cooperate with these schemes. This investigation resulted in more than 30 editors of reputable international journals identified as involved in paper mill activities.

4. Unusual collaboration patterns

One of the peculiarities of paper mill articles is its strange mix of authors. An article on the activity of ground beetles attacking crops in Kazakhstan, for example, is written by authors who are neither affiliated with institutions in Kazakhstan nor experts in insects or agriculture. The authors’ backgrounds are suspiciously heterogeneous, ranging from anaesthesia, dentistry, to biomedical engineering.

5. Anonymous co-authors

Prospective customers of paper mill services usually have to agree to the rules of confidentiality. By agreeing to this rule, buyers have no idea which journal their article will target or who their co-authors will be. Often, the authors listed on the same paper don’t even know each other.

Spotting the red flags: how to detect paper mills articles

Detecting scientific articles produced by paper mills often begins with analyzing retraction patterns carried out by journals.

This can be done in two ways: by tracking post-publication peer reviews on platforms like PubPeer, or by checking the Retraction Watch database, a website that documents retractions of problematic scientific articles.

However, journals rarely state outright that a retraction is due to paper mill fraud. Instead, articles are typically pulled for reasons like improper inclusion of the name and order of authors, inclusion of many irrelevant citations or references, plagiarism, or inclusion of manipulated or duplicated images.

The proportion of scientific articles retracted for being associated with paper mills is much smaller than the estimated total number of paper mill articles currently in circulation.

Retraction Watch data, as of May 2024, only recorded 7,275 retractions of articles related to the paper mill out of a total of 44,000 retractions recorded. In fact, it is estimated that up to 400,000 paper mill articles have infiltrated scientific literature over the past two decades.

Despite significant efforts from publishers and the academic community through organizations such as United2Act, a global alliance initiated by Committee on Publication Ethics (COPE) and STM, these attempts are barely enough.

How paper mills hurt the public

The UK Research Integrity Office—an independent UK charity that offers support to the public, researchers and organisations to promote good academic research practice—estimates that the paper mill industry has gained around $10 million globally.

For example, a Russian paper mill could earn $6.5 million if they sold all the authorship of scientific articles it produced from 2019 to 2021.

In Indonesia, this financial loss directly impacts the public. Public universities rely on the state budget, funded largely by taxpayers, and tuition fees from students to cover operational expenses, including research grants and publication incentives.

Though the exact financial toll of these paper mills is hard to pin down, it is clear that the public are footing the bill for fraudulent research practices, siphoning resources away from enuin academic advancements.

The Conversation

Rizqy Amelia Zein tidak bekerja, menjadi konsultan, memiliki saham, atau menerima dana dari perusahaan atau organisasi mana pun yang akan mengambil untung dari artikel ini, dan telah mengungkapkan bahwa ia tidak memiliki afiliasi selain yang telah disebut di atas.

ref. Paper mills: the ‘cartel-like’ companies behind fraudulent scientific journals – https://theconversation.com/paper-mills-the-cartel-like-companies-behind-fraudulent-scientific-journals-230124

Indonesian social forestry often excludes women from decisions, risking greater inequality

Source: The Conversation – Indonesia – By Tessa Toumbourou, Postdoctoral Research Fellow in Environmental Social Science, The University of Melbourne

Our analysis of Indonesia’s social forestry permits shows that women remain underrepresented in forest management bodies despite efforts to boost their presence, leaving them out of decisions about their forests.

Social forestry redistributes forest management rights to local communities to advance sustainability and local livelihoods. In 2021, the country revised its social forestry regulations to allow one family representative to participate in social forestry management bodies, ‘giving equal opportunity to both men and women.’

However, our analysis of 400 most recent social forestry permit documents, combined with extended, multi-method field research at four sites, shows that women are often excluded from management bodies but are more involved in social forestry business groups (Kelompok Usaha Perhutanan Sosial or KUPS). These groups focus on the processing and sale of forest products.

This low level of participation in management excludes women from decisions about who receives benefits such as land for cultivation, seedlings, equipment, extension training, and technical information provided by the government and NGOs. The absence of women’s presence may deepen local inequalities and hamper effective forest management.

Gender gaps in social forestry

We reviewed the 400 most recent decree letters issued in 2024 that granted forestry management rights. These included 100 permits each for the managements of Village Forests (Hutan Desa) and Community Forests (Hutan Kemasyarakatan) and their respective KUPS (Table 1). Village Forests are rights collectively held and managed by village administrations, while Community Forests are issued to specific farmer or community groups.

Our analysis found that across Indonesia women are often underrepresented in management groups. On average, only 19.54% of members in Village Forest’s management bodies were women, with participation ranging from none to 80%. This number was even lower in Community Forests, averaging 13.95% women, with some groups having no female members and others up to 56.52%.

However, the available data often lacked details about gender in KUPS-related decrees. Only 19 of 100 Village Forests’ KUPS decrees and 23 of 100 Community Forests’ KUPS decrees included this information.

When gender data was included, women were more involved in KUPS of Village Forests, with an average of 46.32% participation. In contrast, their participation in Community Forests’ KUPS was just 13.06%.

These numbers show that progress in gender representation in Indonesia’s social forestry is mixed. While women are more active in economic activities linked to KUPS, they are still sidelined in formal management roles and decision-making.

Understanding uneven participation

Our field research also highlighted how women and men are participating in, and deriving benefits from, social forestry in Indonesia, while exploring factors influencing women’s (and men’s) involvement.

We focused on four social forestry sites — two Village Forests (Sintang; West Kalimantan province, and Muara Enim; South Sumatra province) and two Community Forests (Gunungkidul; Special Region of Yogyakarta, and Enrekang; South Sulawesi province). We selected sites that reflect different levels of women’s participation.

Table 2 highlights a disparity: while women actively engage in forest land use — such as collecting and processing non-timber forest products and cultivating social forestry land — in two sites (Enrekang and Muara Enim) they are not involved in management bodies where decisions about land use, forest resources and benefit distribution are made.

For example, Masna (pseudonym), a farmer and forest user from Enrekang, shared that her involvement in her village’s forest management body (Kelompok Tani Hutan) was limited to preparing snacks while men made decisions.

Why does this happen?

Deeply rooted gender norms significantly limit women’s involvement in social forestry in some sites. These norms often designate unpaid household and care-giving duties to women, positioning men as the primary decision-makers. This affects women’s confidence and participation in village meetings, where forest management decisions are made reduce women’s participation.

Our findings align with earlier studies showing how gender roles, influenced by discourse promoted by the New Order regime, continue to shape these practices of recognising men as breadwinners and landowners, reinforcing their dominance in formal discussions and decision-making bodies.

Although there are no educational requirements for joining social forestry, research shows that those with more education tend to have more influence. In our study, women in social forestry households averaged fewer years of education (6.6 years) compared to men (8.1 years). Lower education levels, socio-economic challenges, and low confidence in public forums, where education often boosts credibility, can further exclude women.

Geographic barriers such as remote forest locations, rough terrain, and poor roads also hinder women’s participation, making travel difficult and limiting their ability to be involved.

Assistance helps, as do local women leaders

In the Sintang and Gunungkidul sites, women have taken on greater roles in forest management bodies.

In Sintang, support from the Indonesian NGO PUPUK (Association for the Improvement of Small Business) significantly boosted women’s participation in the village forest management body. PUPUK facilitated discussions, provided training at convenient times for women, and encouraged male leaders to back greater female involvement. The number of female members increased from just one in 2018 to 12 women and nine men in a newly formed management body in 2022.

The social forestry group in Gunungkidul – initially a male-dominated, government-led reforestation project – evolved into a community-driven initiative with strong female leadership. Support from both government and NGOs enabled women to take more active roles in forestry and agriculture, especially as many men (and some women) left to seek work elsewhere.

A university-educated woman now leads this group and has inspired younger women to join forest management and KUPS activities. These include producing traditional herbal drinks (wedang uwuh) and making snacks from taro, cassava, and arrowroot grown on forest land.

Across the study sites, women involved in KUPS have developed skills in forest management, financial planning, product processing, and marketing, earning modest incomes. These activities have also shifted gender roles. For example, in Sintang, when Mirna (pseudonym) became head of the KUPS, her husband started taking on domestic chores like cooking and childcare to support her work.

What’s next?

Tackling gender disparities in social forestry requires targeted policies to ensure women’s voices, especially from marginalised groups, are heard in decision-making processes that affect their livelihoods and access to resources.

Introducing quotas or affirmative measures for forest management bodies can help close the gender gap and ensure more equitable benefit distribution. Evidence from other Global South regions suggests that at least 30% female representation in forest management bodies is necessary for meaningful participation, enabling women to influence decisions more effectively.

Inclusive governance also depends on fair representation of different ethnic and socio-economic groups, particularly poorer households. When disadvantaged groups are poorly represented, the distribution of benefits suffers, limiting the equitable flow of resources and opportunities.

Partnerships with NGOs and civil society groups skilled in addressing gender differences can empower women and marginalized men with the skills and confidence needed to engage in decision-making bodies.

Creating safe spaces is also vital. This includes holding gender-specific discussions in local languages at times that fit with both women’s and men’s schedules.

The government must also commit to regularly monitoring women’s participation by collecting and publishing accurate gender-disaggregated data, specific to each site and region.

A decree issued by Ministry of Environment and Forestry in August introduces a policy shift that allows individuals — not just groups — to apply for social forestry. This could boost women’s participation, provided targeted support helps them step into leadership roles. Without this backing, the risk remains that social forestry will continue to be dominated by elite men.


Rahpriyanto Alam Surya Putra, the director of The Asia Foundation’s Environmental Governance program in Indonesia, and Ike Sulistiowati, Director of PUPUK Indonesia, contributed to this study.

The Conversation

Tessa Toumbourou received funding from the Australian Department of Foreign Affairs and Trade through KONEKSI (Knowledge Partnership Platform Australia-Indonesia). The views expressed in this publication do not represent the views of the Australian Government.

Andrea received funding from the Australian Department of Foreign Affairs and Trade through KONEKSI (Knowledge Partnership Platform Australia-Indonesia). The views expressed in this publication do not represent the views of the Australian Government.

Gutomo received funding from the Australian Department of Foreign Affairs and Trade through KONEKSI (Knowledge Partnership Platform Australia-Indonesia). The views expressed in this publication do not represent the views of the Australian Government.

Ilmiawan received funding from the Australian Department of Foreign Affairs and Trade through KONEKSI (Knowledge Partnership Platform Australia-Indonesia). The views expressed in this publication do not represent the views of the Australian Government.

Lilis received funding from the Australian Department of Foreign Affairs and Trade through KONEKSI (Knowledge Partnership Platform Australia-Indonesia). The views expressed in this publication do not represent the views of the Australian Government.

Rumayya received funding from the Australian Department of Foreign Affairs and Trade through KONEKSI (Knowledge Partnership Platform Australia-Indonesia). The views expressed in this publication do not represent the views of the Australian Government.

Yulia received funding from the Australian Department of Foreign Affairs and Trade through KONEKSI (Knowledge Partnership Platform Australia-Indonesia). The views expressed in this publication do not represent the views of the Australian Government.

ref. Indonesian social forestry often excludes women from decisions, risking greater inequality – https://theconversation.com/indonesian-social-forestry-often-excludes-women-from-decisions-risking-greater-inequality-238904

Reflecting on 20 years of the Aceh tsunami: From ‘megathrust’ threat to disaster mitigation

Source: The Conversation – Indonesia – By Zulfakriza Z., Associate Professor, Global Geophysics Research Group, Institut Teknologi Bandung

20 years have passed since the Aceh tsunami, which left deep scars on Indonesia, especially for those directly affected. Aceh was also recovering from a three-decade armed conflict between the Free Aceh Movement and the national government

Throughout December 2024, The Conversation Indonesia, in collaboration with academics, is publishing a special edition honouring the 20 years of efforts to rebuild Aceh. We hope this series of articles preserves our collective memory while inspiring reflection on the journey of recovery and peace in the land of ‘Serambi Makkah.’


Sunday, December 26, 2004, 7:58:53 AM (WIB, GMT+7): A 9.1 moment magnitude (Mw) earthquake occurred off the west coast of Aceh. The quake, originating from a depth of 30 kilometers below the sea, triggered a tsunami that devastated the province.

Research in 2021 suggested the earthquake’s magnitude was actually greater than what was previously recorded — 9.2 Mw. Scientists came to this conclusion after recalculating tsunami data using Green’s Function, a mathematical method that analyses how tsunami waves are formed and spread. This gave them a more accurate estimate of how strong the earthquake was.

From December 26, 2004, to February 26, 2005, the United States Geological Survey (USGS) documented about 2,050 aftershocks, a series of aftershock caused by the mainshock.

The effects of the 2004 Aceh earthquake and tsunami extended beyond Indonesia, affecting coastlines in Southeast Asia, South Asia, and possibly Africa. More than 227,000 people were killed, with Aceh alone accounting for approximately 167,000.

The 2004 Aceh Earthquake and Tsunami is known as one of the most devastating natural disasters in history. While it left deep wounds, it also demonstrated the fundamental need for disaster preparedness.

Tectonic map, megathrust zones, and seismic gaps

Indonesia is prone to disasters due to its location in a tectonically active zone where four major plates — Indo-Australian, Eurasian, Pacific, and Philippine — with convergence movement.

Comprising Earth’s rigid outer layer or lithosphere, a tectonic plate is a large, irregularly shaped sheet of solid rock that moves and interacts with other plates to sculpt the surface of the planet over geological time. These plate clashes have the potential to trigger massive earthquakes, particularly in western Sumatra, southern Java, Bali, Nusa Tenggara, the Banda Sea, Maluku, Papua, and Sulawesi.

A shift between two tectonic plates in the Indian Ocean resulted in a thrust fault, causing the 2004 Aceh earthquake. The fault stretched 500 kilometers – roughly the distance between Jakarta and Yogyakarta – with a breadth of about 150 kilometers. Known as a “megathrust earthquake,” the plates shifted by more than 20 meters, releasing enormous energy and causing tsunami waves up to 35 meters high – the height of a 10-story building.

Aside from earthquakes and tsunamis, tectonic movements can also trigger volcanic activity. Indonesia, which is part of the Pacific Ring of Fire, has 127 active volcanoes, making it the world’s most seismically and volcanically active region.

Between 1900 and 2023, Indonesia recorded 14,820 earthquakes with magnitudes greater than 5 Mw. Among these, 15 were more than 8 Mw, including the 2004 Aceh earthquake. Other big earthquakes, like those in Sumba (1977), Biak (1996), Nias (2005), and Bengkulu (2007), also triggered tsunamis, causing substantial casualties and damage.

Indonesia also has several megathrust zones – areas along tectonic plate boundaries prone to generating large earthquakes like the 2004 Aceh event. There are 13 identified megathrust zones near the waters off western Sumatra, southern Java, Bali, Nusa Tenggara, northern Sulawesi, Halmahera, and Papua. These zones are prone to generate quakes of magnitudes ranging from 7.8 to 9.2 Mw, capable of delivering major destruction and tsunamis.

Over the last 30 years, some of Indonesia’s megathrust zones have been releasing seismic energy. These zones were the source of major earthquakes such as 1996 Biak, 1994 Banyuwangi, 2004 Aceh, 2005 Nias, 2006 Pangandaran, and 2007 Bengkulu.

However, data from the past 123 years show that some parts of the megathrust zones rarely experience large earthquakes. This could be because tectonic movements in these locations are stuck, causing stress to build up over time. These “seismic gaps” indicate high-risk zones for future big earthquakes.

A seismic gap, for example, exists between the megathrust zones off the western and eastern coasts of Java. For instance, in western Java’s subduction zone, the slip deficit — or plate movement locked in place — has reached 40-60 mm per year. If this energy is eventually released, it might result in a significant earthquake and possibly a tsunami.

Advances in disaster research

Indonesia’s high disaster risk has attracted scholars from all around the world, particularly following the 2004 Aceh Tsunami. From 2005 to 2024, Google Scholar recorded approximately 1,000 scientific works on Indonesian earthquakes and tsunamis.

These studies have improved our understanding of earthquake causes and trends. For example, research on the 2018 Palu and Sunda Strait tsunamis revealed that neither was directly caused by earthquakes. The Palu tsunami resulted from an undersea landslide triggered by a 7.5 Mw earthquake on September 28, 2018. Meanwhile, the Sunda Strait tsunami was caused by the fall of Mount Anak Krakatau’s volcanic side.

Indonesian academics have also investigated big earthquake origins and aftershocks. Teams from the National Research and Innovation Agency (BRIN), the Meteorology, Climatology, and Geophysics Agency (BMKG), and the Bandung Institute of Technology (ITB) have looked at aftershock patterns to learn more about where earthquakes come from and how they work. Among those closely studied are 2018 Lombok and 2022 Cianjur. This has led to new ideas for reducing risk and damage.

The Indonesian Tsunami Early Warning System (InaTEWS), managed by BMKG, continues to encourage seismic research collaborations. By 2024, the system would have 521 seismic stations spread across Indonesia. This extensive network allows for faster broadcast of earthquake data to the public, notably timely tsunami warnings after major earthquakes.

Mitigation requires collaboration

While scientists continue to investigate tectonic motions, accurately predicting earthquakes and tsunamis remains impossible. Therefore, mitigation and risk reduction are crucial.

Disaster mitigation efforts include public education and the use of earthquake-resistant infrastructure. These require the support of a wide range of stakeholders.

In 2007, three years after the Aceh Tsunami, Indonesia passed a Disaster Management Law, detailing risk reduction activities, including mitigation. This law promotes collaboration among five major elements: government, communities, academics, corporations, and the media — a framework known as the “pentahelix.”

The government acts as a regulator, the media disseminates information, corporations provide financial and technological support, communities serve as field implementers, and academics act as innovators.

Collaboration is essential for successful catastrophe mitigation. However, problems such as sectoral ego frequently impede efforts. For example, a refusal to share data across authorities can jeopardise earthquake research and mitigation efforts.

Finally, disaster risk mitigation is a shared responsibility. Building a more robust and sustainable mitigation system requires improved institutional coordination and communication.

The Conversation

Zulfakriza Z. tidak bekerja, menjadi konsultan, memiliki saham, atau menerima dana dari perusahaan atau organisasi mana pun yang akan mengambil untung dari artikel ini, dan telah mengungkapkan bahwa ia tidak memiliki afiliasi selain yang telah disebut di atas.

ref. Reflecting on 20 years of the Aceh tsunami: From ‘megathrust’ threat to disaster mitigation – https://theconversation.com/reflecting-on-20-years-of-the-aceh-tsunami-from-megathrust-threat-to-disaster-mitigation-245142

Lessons from Aceh: How language unites and segregates in conflicts

Source: The Conversation – Indonesia – By Saiful Akmal, Chair professor, Universitas Islam Negeri Ar-Raniry

20 years have passed since the Aceh tsunami, leaving deep scars on Indonesia, especially for those directly affected. Aceh was also recovering from a three-decade armed conflict between the Free Aceh Movement and the national government

Throughout December 2024, The Conversation Indonesia, in collaboration with academics, is publishing a special edition honouring the 20 years of efforts to rebuild Aceh. We hope this series of articles preserves our collective memory while inspiring reflection on the journey of recovery and peace in the land of ‘Serambi Makkah.’


In December 2022, the Aceh People’s Representative Council (DPR) officially enacted the 2022 Qanun (regional regulation) on the Acehnese language. This regulation mandates that the use of Indonesian, in any form of communications, from scientific works to public services, must be accompanies by Acehnese translations. This move reflects Aceh’s autonomy in preserving local cultures, a key demand of the now-defunct Free Aceh Movement (GAM), which sought independence from Indonesia.

The Aceh conflict that ended with the signing of a peace agreement in August 2005, less than a year after the Aceh devastating tsunami, stemmed from locals’ dissatisfaction with the central government. The separatist movement was triggered by economic inequality and natural resource exploitation.

The Qanun reaffirms the Indonesian government and GAM’s commitment to peace following three-decade armed conflict, as outlined in the 2005 Helsinki Agreement. Language — as an important element in culture — can aid in resolving conflicts. It can reduce psychological barriers and foster trust. Local languages, in particular, can strenthen nationalism by promoting empathy and cultural appreciation.

Language for political mobilisation

The use of language can excarcebate conflicts. It can be used to agitate and mobilise people, create hostile narratives, and be used as a propaganda tool to assert group identity and define friends and foes.

During Soeharto’s dictatorship era, the government’s nationalism policy emphasised the exclusive use of Indonesian as national language, even in regions with strong local cultures and languages like Aceh. Local languages are considered less important than Indonesian. This has led to a decline in the use and teaching of local languages in schools, which in turn can threaten the survival and development of these languages.

During the conflict, using Acehnese could be risky, especially in areas sympathetic to GAM. Speaking local language could lead to accusation of supporting the movement, often resulting in intimidation and arrests by the Indonesian military.

GAM, on the other hand, used Acehnese to raise people’s spirit and gather support during the conflict. Cassettes with songs in local languages played in villages created a sense of solidarity while drawing a stark line between “us” and “them.” This demonstrates how language can be a powerful tool in social and political mobilisation.

Language for conflict resolution

In Aceh, the role of local language in promoting conflict resolution is significant for the following reasons:

1. Reduces psychological barriers

In 2005, Hamid Awaluddin, a Bugis descendant and former Minister of Justice and Human Rights who represented the government in the negotiation of conflict resolution in Aceh, read ‘pantun’, a traditional Malay poem, in Acehnese:

pat ujeun yang hana pirang, pat prang yang hana reuda,” (is there rain that will not stop? Is there a war that cannot be ended?).

Although his Acehnese was not fluent, Hamid’s efforts were warmly received by Wali Nanggroe, Aceh’s cultural leadership, and other people who represented the local communities. His decision to use the local language had created an intimate atmosphere, which then helped reduce tension and increased mutual trust between the two parties.

Language in such contexts becomes a powerful instrument in a peace negotiation process, serving not only as a technical communication tool, but also as a symbol of empathy and respect. It allows the conflicting parties to feel more valued and share emotions, which then can pave the way for a more constructive and inclusive dialogue.

2. Strengthening the sense of nationalism

Case studies show that the recognition of the Acehnese language, identity and culture by the central government can foster Indonesian nationalism among the local communities. According to a research, building something from within, and respecting local conditions contributes to a more permanent peace-building effort.

The government’s move to acknowledge local languages of Aceh and Gayo as intangible heritages has allowed the people to use them in public spaces. As a result, this strengthened the sense of belonging of Acehnese people to the state

By providing space to local languages, the state shows respect for existing cultural diversity–allowing local communities feel more integrated with the national framework.

An inclusive approach

The establishment of the Acehnese Language Qanun is not without risks. While it is true that the Acehnese Language Qanun can increase nationalism because it makes people feel appreciated and recognised, it may negatively impact other ethnic languages.

Aceh is home to 13 other local languages. Enacting Acehnese as an official regional language can make non-Acehnese groups feel isolated, as evidenced by past protests from the Gayo community and other minorities.

For example, protests arose when being fluent in Acehnese became one of the requirements to become a local leader such as a Wali Nanggroe. Additionally, replacing the Gayo hymn with the Acehnese hymn in ceremonial activities has angered the Gayo people as the majority ethnic group in the area.

Without proper mitigation, this policy risks alienating minority groups, potentially leading to feelings of forced assimilation for minority languages. This will harm the efforts to build sustainable peace in Aceh. Therefore, an inclusive approach to language policy is very important.

The efforts to promote the Acehnese language should be accompanied by similar steps to recognise and preserve the languages and cultural expressions of other ethnic groups in Aceh.

This inclusive approach is crucial to building long-term peace and social cohesion in the region. After all, Aceh’s experience teaches us that language has two sides in conflict resolution: as a tool that strengthens peace, or sharpens differences.

The Conversation

Saiful Akmal received funding from the Ministry of Religion of the Republic of Indonesia in 2024 for research entitled “Language, Identity, and Conflict Resolution: The Case of Aceh and Patani.”.

Melly Masni menerima dana dari Kementerian Agama Republik Indonesia tahun 2024 untuk riset berjudul “Language, Identity, and Conflict resolution: The Case of Aceh and Patani”.

ref. Lessons from Aceh: How language unites and segregates in conflicts – https://theconversation.com/lessons-from-aceh-how-language-unites-and-segregates-in-conflicts-245481

High skills, low protection: the legal hurdles for foreign workers in Indonesia

Source: The Conversation – Indonesia – By Wayne Palmer, Senior Research Fellow, Bielefeld University

ilikeyellow/Shutterstock

Developing countries like Indonesia use foreign high-skilled and high-wage workers to drive economic growth and innovation. However, protection of their legal rights is often neglected, affecting these workers’ productivity and well-being and Indonesia’s reputation as a destination country for employment.

My research delves into the flaws of Indonesia’s labour market institutions, such as the national labour dispute settlement system, revealing that current mechanisms are inadequate in protecting the rights of high-skilled foreign workers.

The study

My findings show the national dispute settlement system exhibits significant systemic shortcomings, such as processing cases slowly and siding with employers, which limit its capacity to protect all workers effectively. But disputes involving foreign workers are further complicated by the fact that immigration law allows employers to cancel residence permits, meaning that the government requires the workers to leave the country even though the workers may have been unfairly dismissed.

Foreign workers are mainly from Northeast Asia (China, Japan and Korea), and their use on investment-tied projects coupled with Indonesia’s downstreaming programme will ensure their numbers continue to grow. In 2023, the Indonesian government issued 168,048 permits for foreigners to work in Indonesia with the top three destinations being Central Sulawesi (18,678), Jakarta (13,862) and West Java (10,807). By July 2024, the government had already issued more than 14% more permits than by the same time the previous year.

My study examined 92 labour disputes involving foreign workers between 2006 (when the new national dispute settlement system was implemented) and 2022, which were settled by the Industrial Relations Court. One additional dispute was filed in 2023, but the Industrial Relations Court has not yet published the settlement despite a legal requirement to do so.

I complemented these court settlements with 98 qualitative interviews with other stakeholders, including policymakers, labour rights activists, legal professionals, and other foreign workers, such as foreign spouses, remote workers and digital nomads.

As in other countries too, the number of registered labour disputes is only the tip of the iceberg, as workers tend to cut their losses and move on rather than invest time, energy and limited financial resources in challenging their better-resourced employers.

Employers were all Indonesian companies, so no foreign workers who filed a lawsuit worked for a multinational company, and those who did so had at least 20 nationalities.


CC BY

In terms of geographical distribution, the studied disputes were settled in 13 local jurisdictions, and were mostly lodged by workers rather than employers.

The nature of the disputes mostly involved claims that an employment contract had been terminated prematurely (87 cases), while a much smaller number involved resignation (4 cases) or were unknown (1 case). Of the 92 claims, 83 were initiated by workers, and eight by an employer. In one case, the lodging party was not recorded in the final decision.

Hiring a private lawyer

Employers used the Immigration Law to undermine the protective role of the Manpower Law – as it stands foreign workers are only entitled to employment protection if they hold a valid residence permit, which employers can and do shorten. Doing so shows that the Indonesian government prioritizes the flexibility of employers at the expense of employment protection for foreign workers.

In at least 92% cases, foreign workers used paid assistance of a private lawyer to represent themselves at formal meetings and hearings required by the Disputes Settlement Law, the cost of which could be hefty.

As one foreign worker explained:

It’s always in the back of your mind, to do whatever to make employers happy if you want to stay. No matter what the work permit and contract say, they can ask immigration to kick us out within a week!“

A retired government official responsible for designing policy regarding foreign workers was surprised when he heard this, explaining that:

I thought they could look after themselves because they earn such high wages. Well, higher than the average Indonesian worker, that is.

Hiring a private lawyer is the only way to represent themselves throughout the dispute resolution process because they need to leave Indonesia once they are fired. Not having the legal right to remain in Indonesia makes it very difficult – even impossible – to do it without them.

Addressing institutional failures

Engaging a private lawyer served as an ‘institutional fix’ that enabled most foreign workers to engage with Indonesia’s labour dispute settlement system by attending formal meetings and hearings, as well as filling out required paperwork and sending essential letters and replies.

Addressing this institutional failure requires a shift in law and policy. Firstly, legal reforms are essential to ensure that immigration and employment laws are integrated to enable foreign workers to have access to legal processes intended to help protect labour rights. At a minimum, this would involve amending policy to prevent employers from cancelling residence permits so that foreign workers need to leave the country prematurely.

Alternatively, the Directorate-General of Immigration could still permit employers to do so, but then provide the affected foreign workers with a limited-stay visa so that they can remain in Indonesia to engage with the legal process. The Hong Kong Immigration Department does this for Indonesian migrant workers.

Secondly, there is a need for enhanced support systems that provide immediate and effective assistance to foreign workers. Government agencies tasked with settling labour disputes, such as local manpower offices and the Industrial Relations Court, should be equipped with adequate resources and trained personnel to handle migrant labour issues. Doing so would decrease the reliance of foreign workers on private lawyers.

Failure to protect the employment rights of foreign workers has the potential to damage Indonesia’s reputation as a destination country for employment. Such damage could undermine Indonesia’s ambitious plans to build a new capital city (Ibu Kota Nusantara) with the assistance of foreign workers, and undermine the government’s downstreaming programme, which helps Indonesia earn more from the export of raw minerals.

The Conversation

Wayne Palmer has received research funding from the International Labour Organization, the Freedom Fund, and the Australian Research Council.

ref. High skills, low protection: the legal hurdles for foreign workers in Indonesia – https://theconversation.com/high-skills-low-protection-the-legal-hurdles-for-foreign-workers-in-indonesia-230795

How do atoms form? A physicist explains where the atoms that make up everything around come from

Source: The Conversation – USA (2) – By Stephen L. Levy, Associate Professor of Physics and Applied Physics and Astronomy, Binghamton University, State University of New York

Many heavy atoms form from a supernova explosion, the remnants of which are shown in this image. NASA/ESA/Hubble Heritage Team

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.


How do atoms form? – Joshua, age 7, Shoreview, Minnesota


Richard Feynman, a famous theoretical physicist who won the Nobel Prize, said that if he could pass on only one piece of scientific information to future generations, it would be that all things are made of atoms.

Understanding how atoms form is a fundamental and important question, since they make up everything with mass.

The question of where atoms come from requires a lot of physics to be answered completely – and even then, physicists like me only have good guesses to explain how some atoms are formed.

What is an atom?

An atom consists of a heavy center, called the nucleus, made of particles called protons and neutrons. An atom has lighter particles called electrons that you can think of as orbiting around the nucleus.

The electrons each carry one unit of negative charge, the protons each carry one unit of positive charge, and the neutrons have no charge. An atom has the same number of protons as electrons, so it is neutral − it has no overall charge.

A diagram of an atom, with protons and neutrons clumped together in the center and ovals representing electron orbits surrounding them.
An atom consists of positively charged protons, neutrally charged neutrons and negatively charged electrons.
AG Caesar/Wikimedia Commons, CC BY-SA

Now, most of the atoms in the universe are the two simplest kinds: hydrogen, which has one proton, zero neutrons and one electron; and helium, which has two protons, two neutrons and two electrons. Of course, on Earth there are lots of atoms besides these that are just as common, such as carbon and oxygen, but I’ll talk about those soon.

An element is what scientists call a group of atoms that are all the same, because they all have the same number of protons.

When did the first atoms form?

Most of the universe’s hydrogen and helium atoms formed around 400,000 years after the Big Bang, which is the name for when scientists think the universe began, about 14 billion years ago.

Why did they form at that time? Astronomers know from observing distant exploding stars that the size of the universe has been getting bigger since the Big Bang. When the hydrogen and helium atoms first formed, the universe was about 1,000 times smaller than it is now.

And based on their understanding of physics, scientists believe that the universe was much hotter when it was smaller.

Before this time, the electrons had too much energy to settle into orbits around the hydrogen and helium nuclei. So, the hydrogen and helium atoms could form only once the universe cooled down to something like 5,000 degrees Fahrenheit (2,760 degrees Celsius). For historical reasons, this process is misleadingly called recombination − combination would be more descriptive.

The helium and deuterium − a heavier form of hydrogen − nuclei formed even earlier, just a few minutes after the Big Bang, when the temperature was above 1 billion F (556 million C). Protons and neutrons can collide and form nuclei like these only at very high temperatures.

Scientists believe that almost all the ordinary matter in the universe is made of about 90% hydrogen atoms and 8% helium atoms.

How do more massive atoms form?

So, the hydrogen and helium atoms formed during recombination, when the cooler temperature allowed electrons to fall into orbits. But you, I and almost everything on Earth is made of many more massive atoms than just hydrogen and helium. How were these atoms made?

The surprising answer is that more massive atoms are made in stars. To make atoms with several protons and neutrons stuck together in the nucleus requires the type of high-energy collisions that occur in very hot places. The energy needed to form a heavier nucleus needs to be large enough to overcome the repulsive electric force that positive charges, like two protons, feel with each other.

A close up of a bright star, which looks like a sphere with some flashes on its surface, against a dark background.
The immense heat and pressure in stars can form atoms through a process called fusion.
NASA/SDO

Protons and neutrons also have another property – kind of like a different type of charge – that is strong enough to bind them together once they are able to get very close together. This property is called the strong force, and the process that sticks these particles together is called fusion.

Scientists believe that most of the elements from carbon up to iron are fused in stars heavier than our Sun, where the temperature can exceed 1 billion F (556 million C) – the same temperature that the universe was when it was just a few minutes old.

The periodic table of elements, color-coded by how each element formed. Lighter elements formed by cosmic ray fission or exploding stars, while larger elements formed by merging neurtron stars or dying low mass stars. Hydrogen and Helium formed through Big Bang fusion.
This periodic table shows which astronomical processes scientists believe are responsible for forming each of the elements.
Cmglee/Wikimedia Commons (image) and Jennifer Johnson/OSU (data), CC BY-SA

But even in hot stars, elements heavier than iron and nickel won’t form. These require extra energy, because the heavier elements can more easily break into pieces.

In a dramatic event called a supernova, the inner core of a heavy star suddenly collapses after it runs out of fuel to burn. During the powerful explosion this collapse triggers, elements that are heavier than iron can form and get ejected out into the universe.

Astronomers are still figuring out the details of other fantastic stellar events that form larger atoms. For example, colliding neutron stars can release enormous amounts of energy – and elements such as gold – on their way to forming black holes.

Understanding how atoms are made just requires learning a little general relativity, plus some nuclear, particle and atomic physics. But to complicate matters, there is other stuff in the universe that doesn’t appear to be made from normal atoms at all, called dark matter. Scientists are investigating what dark matter is and how it might form.


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.

The Conversation

Stephen L. Levy receives funding from the National Science Foundation and the National Institutes of Health. He is affiliated with CyteQuest, Inc.

ref. How do atoms form? A physicist explains where the atoms that make up everything around come from – https://theconversation.com/how-do-atoms-form-a-physicist-explains-where-the-atoms-that-make-up-everything-around-come-from-256172

Astronomy has a major data problem – simulating realistic images of the sky can help train algorithms

Source: The Conversation – USA (2) – By John Peterson, Assoc. Professor of Physics and Astronomy, Purdue University

A simulation of a set of synthetic galaxies. Photons are sampled from these galaxies and have been simulated through the Earth’s atmosphere, a telescope and a sensor using a code called PhoSim. John Peterson/Purdue

Professional astronomers don’t make discoveries by looking through an eyepiece like you might with a backyard telescope. Instead, they collect digital images in massive cameras attached to large telescopes.

Just as you might have an endless library of digital photos stored in your cellphone, many astronomers collect more photos than they would ever have the time to look at. Instead, astronomers like me look at some of the images, then build algorithms and later use computers to combine and analyze the rest.

But how can we know that the algorithms we write will work, when we don’t even have time to look at all the images? We can practice on some of the images, but one new way to build the best algorithms is to simulate some fake images as accurately as possible.

With fake images, we can customize the exact properties of the objects in the image. That way, we can see if the algorithms we’re training can uncover those properties correctly.

My research group and collaborators have found that the best way to create fake but realistic astronomical images is to painstakingly simulate light and its interaction with everything it encounters. Light is composed of particles called photons, and we can simulate each photon. We wrote a publicly available code to do this called the photon simulator, or PhoSim.

The goal of the PhoSim project is to create realistic fake images that help us understand where distortions in images from real telescopes come from. The fake images help us train programs that sort through images from real telescopes. And the results from studies using PhoSim can also help astronomers correct distortions and defects in their real telescope images.

The data deluge

But first, why is there so much astronomy data in the first place? This is primarily due to the rise of dedicated survey telescopes. A survey telescope maps out a region on the sky rather than just pointing at specific objects.

These observatories all have a large collecting area, a large field of view and a dedicated survey mode to collect as much light over a period of time as possible. Major surveys from the past two decades include the SDSS, Kepler, Blanco-DECam, Subaru HSC, TESS, ZTF and Euclid.

The Vera Rubin Observatory in Chile has recently finished construction and will soon join those. Its survey begins soon after its official “first look” event on June 23, 2025. It will have a particularly strong set of survey capabilities.

The Rubin observatory can look at a region of the sky all at once that is several times larger than the full Moon, and it can survey the entire southern celestial hemisphere every few nights.

An observatory, which looks like a building with a dome atop it, on a mountainside, with a starry sky shown in the background.
The Vera Rubin Observatory will take in lots of light to construct maps of the sky.
Rubin Observatory/NSF/AURA/B. Quint, CC BY-SA

A survey can shed light on practically every topic in astronomy.

Some of the ambitious research questions include: making measurements about dark matter and dark energy, mapping the Milky Way’s distribution of stars, finding asteroids in the solar system, building a three-dimensional map of galaxies in the universe, finding new planets outside the solar system and tracking millions of objects that change over time, including supernovas.

All of these surveys create a massive data deluge. They generate tens of terabytes every night – that’s millions to billions of pixels collected in seconds. In the extreme case of the Rubin observatory, if you spent all day long looking at images equivalent to the size of a 4K television screen for about one second each, you’d be looking at them 25 times too slow and you’d never keep up.

At this rate, no individual human could ever look at all the images. But automated programs can process the data.

Astronomers don’t just survey an astronomical object like a planet, galaxy or supernova once, either. Often we measure the same object’s size, shape, brightness and position in many different ways under many different conditions.

But more measurements do come with more complications. For example, measurements taken under certain weather conditions or on one part of the camera may disagree with others at different locations or under different conditions. Astronomers can correct these errors – called systematics – with careful calibration or algorithms, but only if we understand the reason for the inconsistency between different measurements. That’s where PhoSim comes in. Once corrected, we can use all the images and make more detailed measurements.

Simulations: One photon at a time

To understand the origin of these systematics, we built PhoSim, which can simulate the propagation of light particles – photons – through the Earth’s atmosphere and then into the telescope and camera.

A simulation of photons traveling from a single star to the Vera Rubin Observatory, made using PhoSim. The layers of turbulence in the atmosphere move according to wind patterns (top middle), and the mirrors deform (top right) depending on the temperature and forces exerted on them. The photons with different wavelengths (colors) are sampled from a star, refract through the atmosphere and then interact with the telescope’s mirrors, filter and lenses. Finally, the photons eject electrons in the sensor (bottom middle) that are counted in pixels to make an image (bottom right). John Peterson/Purdue

PhoSim simulates the atmosphere, including air turbulence, as well as distortions from the shape of the telescope’s mirrors and the electrical properties of the sensors. The photons are propagated using a variety of physics that predict what photons do when they encounter the air and the telescope’s mirrors and lenses.

The simulation ends by collecting electrons that have been ejected by photons into a grid of pixels, to make an image.

Representing the light as trillions of photons is computationally efficient and an application of the Monte Carlo method, which uses random sampling. Researchers used PhoSim to verify some aspects of the Rubin observatory’s design and estimate how its images would look.

Rubin simulation with PhoSim, showing black dots representing stars and galaxies against a bright background
A simulations of a series of exposures of stars, galaxies and background light through the Rubin observatory using PhoSim. Photons are sampled from the objects and then interact with the Earth’s atmosphere and Rubin’s telescope and camera.
John Peterson/Purdue

The results are complex, but so far we’ve connected the variation in temperature across telescope mirrors directly to astigmatism – angular blurring – in the images. We’ve also studied how high-altitude turbulence in the atmosphere that can disturb light on its way to the telescope shifts the positions of stars and galaxies in the image and causes blurring patterns that correlate with the wind. We’ve demonstrated how the electric fields in telescope sensors – which are intended to be vertical – can get distorted and warp the images.

Researchers can use these new results to correct their measurements and better take advantage of all the data that telescopes collect.

Traditionally, astronomical analyses haven’t worried about this level of detail, but the meticulous measurements with the current and future surveys will have to. Astronomers can make the most out of this deluge of data by using simulations to achieve a deeper level of understanding.

The Conversation

John Peterson 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. Astronomy has a major data problem – simulating realistic images of the sky can help train algorithms – https://theconversation.com/astronomy-has-a-major-data-problem-simulating-realistic-images-of-the-sky-can-help-train-algorithms-258786

How do scientists calculate the probability that an asteroid could hit Earth?

Source: The Conversation – USA (2) – By Toshi Hirabayashi, Associate Professor of Aerospace Engineering, Georgia Institute of Technology

NASA’s Webb telescope captured a photo of the asteroid 2024 YR4 from afar. European Space Agency via AP

I was preparing for my early morning class back in January 2025 when I received a notice regarding an asteroid called 2024 YR4. It said the probability it could hit Earth was unusually high.

As defending Earth from unexpected intruders such as asteroids is part of my expertise, I immediately started receiving questions from my students and colleagues about what was happening.

When scientists spot an asteroid whose trajectory might take it close to Earth, they monitor it frequently and calculate the probability that it might collide with our planet. As they receive more observational data, they get a better picture of what could happen.

Just having more data points early doesn’t make scientists’ predictions better. They need to keep following the asteroid as it moves through space to better understand its trajectory.

Reflecting on the incident a few months later, I wondered whether there might have been a better way for scientists to communicate about the risk with the public. We got accurate information, but as the questions I heard indicated, it wasn’t always enough to understand what it actually means.

Numbers change every day

The 2024 YR24 asteroid has a diameter of about 196 feet (60 meters) – equivalent to approximately a 15-story building in length.

At the time of the announcement in January, the asteroid’s impact probability was reported to exceed 1%. The impact probability describes how likely a hazardous asteroid is to hit Earth. For example, if the impact probability is 1%, it means that in 1 of 100 cases, it hits Earth. One in 100 is kind of rare, but still too close for comfort if you’re talking about the odds of a collision that could devastate Earth.

Over time, though, further observations and analyses revealed an almost-zero chance of this asteroid colliding with Earth.

After the initial notice in January, the impact probability continuously increased up to 3.1% on Feb. 18, but dropped to 1.5% on Feb. 19. Then, the impact probability continuously went down, until it hit 0.004% on Feb. 24. As of June 15, it now has an impact probability of less than 0.0000081%.

A diagram showing the orbit paths of Earth, 2024 YR4 and some other planets in the solar system. 2024 YR4's orbit intersects with Earth's.
The orbit of 2024 YR4 will take it close to Earth, but scientists have found the chance of a collision to be exceedingly low.
NASA/JPL

But while the probability of hitting Earth went down, the probability of the asteroid hitting the Moon started increasing. It went up to 1.7% on Feb. 24. As of April 2, it is 3.8%.

If it hits the Moon, some ejected materials from this collision could reach the Earth. However, these materials would burn away when they enter the Earth’s thick atmosphere.

Impact probability

To see whether an approaching object could hit Earth, researchers find out what an asteroid’s orbit looks like using a technique called astrometry. This technique can accurately determine an object’s orbit, down to only a few kilometers of uncertainty. But astrometry needs accurate observational data taken for a long time.

If an asteroid might get close to Earth, astronomers take observational data to better track the object’s path and eliminate uncertainty.

Any uncertainty in the calculation of the object’s orbit causes variations in the predicted solution. Instead of one precise orbit, the calculation usually gives scientists a cloud of its possible orbits. The ellipse enclosing these locations is called an error ellipse.

The impact probability describes how many orbital predictions in this ellipse hit the Earth.

Without enough observational data, the orbital uncertainty is high, so the ellipse tends to be large. In a large ellipse, there’s a higher chance that the ellipse “accidentally” includes Earth – even if the center is off the planet. So, even if an asteroid ultimately won’t hit Earth, its error ellipse might still include the planet before scientists collect enough data to narrow down the uncertainty.

As the level of uncertainty goes down, the ellipse shrinks. So, when Earth is inside a small error ellipse, the impact probability may become higher than when it’s inside a large error ellipse. Once the error ellipse shrinks enough that it no longer includes Earth, the impact probability goes down significantly. That’s what happened to 2024 YR4.

A diagram showing impact probability on the y axis and time on the x axis, with three drawings of the Earth and an error ellipse. As time goes on, the ellipse shrinks and in the third drawing it isn't overlapping with the Earth.
As the error ellipse shrinks, the chance of the asteroid hitting Earth either goes down or goes way up, if it ends up overlapping with the Earth.
Toshi Hirabayashi

The impact probability is a single, practical value offering meaningful insight into an impact threat. However, just using the impact probability without any context may not provide meaningful guidelines to the public, as we saw with 2024 YR4.

Holding on and waiting for more data to refine a collision prediction, or introducing new metrics for assessing impacts on Earth, are alternative courses of action to provide people with better guidelines for future threats before adding confusion and fear.

The Conversation

I have been studying planetary defense, particularly being part of past, ongoing, and future small body missions. I was part of the NASA/DART mission. I am currently part of the NASA/Lucy mission and the ESA/Hera mission. I am also on the Hayabusa2# team, led by the Japanese Aerospace Exploration Agency (JAXA), as part of an international collaboration. I have no affiliation with JAXA.

ref. How do scientists calculate the probability that an asteroid could hit Earth? – https://theconversation.com/how-do-scientists-calculate-the-probability-that-an-asteroid-could-hit-earth-249834

Uranium enrichment: A chemist explains how the surprisingly common element is processed to power reactors and weapons

Source: The Conversation – USA (2) – By André O. Hudson, Dean of the College of Science, Professor of Biochemistry, Rochester Institute of Technology

Yellowcake is a concentrated form of mined and processed uranium. Nuclear Regulatory Commission, CC BY

When most people hear the word uranium, they think of mushroom clouds, Cold War standoffs or the glowing green rods from science fiction. But uranium isn’t just fuel for apocalyptic fears. It’s also a surprisingly common element that plays a crucial role in modern energy, medicine and geopolitics.

Uranium reentered the global spotlight in June 2025, when the U.S. launched military strikes on sites in Iran believed to be housing highly enriched uranium, a move that reignited urgent conversations around nuclear proliferation. Many headlines have mentioned Iran’s 60% enrichment of uranium, but what does that really mean?

As a biochemist, I’m interested in demystifying this often misunderstood element.

What is uranium?

Uranium holds the 92nd position on the periodic table, and it is a radioactive, metallic element. Radioactivity is a natural process where some atoms – like uranium, thorium and radium – break down on their own, releasing energy.

The German chemist Martin Heinrich Klaproth initially identified uranium in 1789, and he named it after the newly discovered planet Uranus. However, its power was not unlocked until the 20th century, when scientists discovered that uranium atoms could split via a process known as nuclear fission. In fission, the nucleus of the atom splits into two or more nuclei, which releases large amounts of energy.

Uranium is found almost everywhere. It is in rocks, soil and water. There are even traces of uranium in plants and animals – albeit tiny amounts. Most of it is found in the Earth’s crust, where it is mined and concentrated to increase the amount of its most useful radioactive form, uranium-235.

The enrichment dilemma

Uranium-235 is an isotope of uranium, which is a version of an element that has the same basic identity but weighs a little more or less. Think about apples from the same tree. Some are big and some are small, but they are all apples – even though they have slightly different weights. Basically, an isotope is the same element but with a different mass.

Unprocessed uranium is mostly uranium-238. It only contains approximately 0.7% uranium-235, the isotope that allows the most nuclear fission to occur. So, the enrichment process concentrates uranium-235.

Enrichment can make uranium more useful for the development of nuclear weapons, since natural uranium doesn’t have enough uranium-235 to work well in reactors or weapons. The process usually contains three steps.

Centrifuges spin the uranium to separate out its isotopes.

The first step is to convert the uranium into a gas, called uranium hexafluoride. In the second step, the gas gets funneled into a machine called a centrifuge that spins very fast. Because uranium-235 is a little lighter than uranium-238, it moves outward more slowly when spun, and the two isotopes separate.

It’s sort of like how a salad spinner separates water from lettuce. One spin doesn’t make much of a difference, so the gas is spun through many centrifuges in a row until the uranium-235 is concentrated.

Uranium can typically power nuclear plants and generate electricity when it is 3%-5% enriched, meaning 3%-5% of the uranium is uranium-235. At 20% enriched, uranium-235 is considered highly enriched uranium, and 90% or higher is known as weapons-grade uranium.

Three pie charts showing the proportion of isotopes in each type of uranium. Natural uranium is almost all U238, low-enriched uranium is 3%-20% U235, highly enriched uranium is mostly U235
The enrichment level depends on the proportion of uranium-235 to uranium-238.
Wikimedia Commons

This high grade works in nuclear weapons because it can sustain a fast, uncontrolled chain reaction, which releases a large amount of energy compared with the other isotopes.

Uranium’s varied powers

While many headlines focus on uranium’s military potential, this element also plays a vital role in modern life. At low enrichment levels, uranium powers nearly 10% of the world’s electricity.

In the U.S., many nuclear power plants run on uranium fuel, producing carbon-free energy. In addition, some cancer therapies and diagnostic imaging technologies harness uranium to treat diseases.

The smoking stacks of a nuclear power plant
Enriched uranium is used for nuclear power.
Raimond Spekking/Wikimedia Commons, CC BY-SA

In naval technology, nuclear-powered submarines and aircraft carriers rely on enriched uranium to operate silently and efficiently for years.

Uranium is a story of duality. It is a mineral pulled from ancient rocks that can light up a city or wipe one off the map. It’s not just a relic of the Cold War or science fiction. It’s real, it’s powerful, and it’s shaping our world – from global conflicts to cancer clinics, from the energy grid to international diplomacy.

In the end, the real power is not just in the energy released from the element. It is in how people choose to use it.

The Conversation

André O. Hudson receives funding from the National Institutes of Health.

ref. Uranium enrichment: A chemist explains how the surprisingly common element is processed to power reactors and weapons – https://theconversation.com/uranium-enrichment-a-chemist-explains-how-the-surprisingly-common-element-is-processed-to-power-reactors-and-weapons-259646