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Glass: Neither a solid nor a liquid, this common yet complicated material is still surprising scientists

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Glass: Neither a solid nor a liquid, this common yet complicated material is still surprising scientists

Most glass is made by melting down soda ash, limestone and quartz sand.
gezgin01/iSock via Getty Images

John Mauro, Penn State and Katelyn Kirchner, Penn State

Glass is a material of many faces: It is both ancient and modern, strong yet delicate, and able to adopt almost any shape or color. These properties of glass are why people use it to make everything from smartphone screens and fiber-optic cables to vials that hold vaccines.

Humankind has been using glass in some fashion for millennia, and researchers are still finding new uses for it today. It’s not uncommon to hear the oft-repeated factoid that glass is actually a liquid, not a solid. But the reality is much more interesting – glass does not fit neatly into either of those categories and is in many ways a state of matter all its own. As two materials scientists who study glass, we are constantly trying to improve our understanding of this unique material and discover new ways to use glass in the future.

A large block of shiny black stone.
Obsidian is a naturally formed glass.
Layne Kennedy/Corbis Documentary via Getty Images

What is glass?

The best way to understand glass is to understand how it is made.

The first step to make glass requires heating up a mixture of minerals – often soda ash, limestone and quartz sand – until they melt into a liquid at around 2,700 degrees Fahrenheit (1,480 Celsius). In this state, the minerals are freely flowing in the liquid and move in a disordered way. If this liquid cools down fast enough, instead of solidifying into an organized, crystalline structure like most solids, the mixture solidifies while maintaining the disordered structure. It is the atomically disordered structure that defines glass.

Three graphics showing atomic structure ranging from ordered to chaotic.
When molten glass cools, it freezes the disordered, amorphous structure it had as a liquid.
Cdang/Wikimedia Commons, CC BY-SA

On short timescales, glass behaves much like a solid. But the liquidlike structure of glass means that over a long enough period of time, glass undergoes a process called relaxation. Relaxation is a continuous but extremely slow process where the atoms in a piece of glass will slowly rearrange themselves into a more stable structure. Over 1 billion years, a typical piece of glass will change shape by less than 1 nanometer – about 1/70,000 the diameter of human hair. Due to the slow rate of change, the myth that old windows are thicker at the bottom due to centuries of gravity pulling on the slowly flowing glass is not true.

Colloquially, the word glass often refers to a hard, brittle, transparent substance made of fused sand, soda and lime. Yet there are many types of glass that are not transparent, and glass can be made from any combination of elements as long as the liquid mixture can be cooled fast enough to avoid crystallization.

From the Stone Age to today

A decorative, yellowish glass cup.
Humans have been creating tools with glass for thousands of years, like this Roman cup from the fourth century.
MatthiasKabel/Wikimedia Commons, CC BY-SA

Humans have been using glass for more than 4,000 years, with some of the earliest uses being for decorative glass beads and arrowheads. Archaeologists have also discovered evidence of 2,000-year-old glass workshops. One such ancient workshop was uncovered near Haifa in modern Israel and dates back to around 350 C.E. There, archaeologists discovered pieces of raw glass, glass-melting furnaces, utilitarian glass vessels and debris from glass-blowing.

Modern glass manufacturing began in the early 20th century with the development of mass production techniques for glass bottles and flat glass sheets. Glass became an essential part of the electronics and telecommunications industry in the latter part of the 20th century and now forms the backbone for the internet.

A cable with light coming out of both ends.
Fiber-optic cables use glass to efficiently transmit information.
Hustvedt/Wikimedia Commons, CC BY-SA

Glass enabling technologies of tomorrow

Today, scientists are far beyond simply using glass as the material for a cup or a mirror. At the cutting edge of research into glass is the ability to manipulate its complex atomic structure and relaxation process to achieve certain properties.

Because glass is atomically disordered and always changing, any two points on a piece of glass are likely to have slightly different properties – whether it is strength, color, conductivity or something else. Because of these differences, two similar pieces of glass that were made in the same way using the same materials can behave very differently.

To better predict how a piece of glass behaves, our team has been researching how to quantify and manipulate the chaotic and ever-changing atomic structure of glass. Recent advances in this field have had direct benefits to existing technologies.

For example, phone screens do not crack as easily as they did in 2014 in part because new processing techniques decrease the differences in atomic bond strengths to make it harder for cracks to propagate. Similarly, internet speeds have vastly improved over the last 20 years because researchers have figured out ways to make the density of glass used for optical fibers more uniform and, therefore, more efficient at transmitting data.

A deeper understanding of how to manipulate the changing, chaotic structure of glass could lead to big advancements in technology in the coming years. Researchers are currently working on a range of projects, including glass batteries that could enable faster charging speeds and improved reliability, fiberglass wind turbines that require less maintenance than existing turbines, and improved memory storage devices.The Conversation

John Mauro, Professor of Materials Science and Engineering, Penn State and Katelyn Kirchner, PhD Candidate in Materials Science, Penn State

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

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Who’s who at the Vatican?

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theconversation.com – Daniel Speed Thompson, Associate Professor of Religious Studies, University of Dayton – 2025-03-03 07:18:00

Who’s who at the Vatican?

Deacons take part in a mass in St. Peter’s Basilica that was supposed to be presided over by Pope Francis.
AP Photo/Alessandra Tarantino

Daniel Speed Thompson, University of Dayton

For more than two weeks, eyes have been on the Vatican, awaiting news about Pope Francis’ health. The pope has been at Rome’s Gemelli Hospital since Feb. 14, 2025, being treated for double pneumonia and other complications.

When a pope is ill, resigns or passes away, who steps in? And who else helps lead the Holy See? The Conversation U.S. asked Daniel Speed Thompson, a theologian at the University of Dayton, for some insight into Vatican City.

Who are the most powerful people at the Vatican, besides the pope?

The Vatican houses the central government of the Catholic Church and is also an independent city-state. The pope is both the head of the Catholic Church and head of state.

In order to govern both, he has the Roman Curia, meaning “court.” In modern terms, the Curia is the papal bureaucracy. It is an extension of the pope’s authority.

In Catholic doctrine, the pope has the highest authority in the church. He can exercise it alone or with the College of Bishops, made up of all the bishops in the world. Bishops named by the pope to the office of “cardinal” can, if under 80 years old, vote to elect a new pope. Some cardinals, but by no means all, serve in the papal Curia in Rome.

Besides the pope, curial officials who oversee important aspects of the church’s political and religious life are often powerful figures. For example, the secretariat of state, headed by Cardinal Pietro Parolin, oversees relations with other countries and international organizations. It also oversees the Vatican’s diplomatic corps.

Two men in black robes with red skullcaps and red sashes walk on a paved road, flanking a man in white robes.
Pope Francis smiles as he walks alongside Vatican Secretary of State Pietro Parolin, left, and Cardinal Giuseppe Versaldi at the Vatican in 2014.
AP Photo/Gregorio Borgia

The Dicastery – “department” – for the Doctrine of the Faith, led by Cardinal Víctor Manuel Fernández, addresses questions about correct Catholic teaching on faith and morals. The Dicastery of Bishops, headed by Cardinal Robert Prevost, coordinates the nominations of new bishops around the world.

All these officials work under the authority of the pope, advocating for and implementing his agenda. For example, Prevost has suggested that all Catholics should be involved in the selection of bishops. This idea is linked with Francis’ call for a more “synodal” church: one that is less hierarchical and shaped by lay Catholics’ concerns and challenges.

If a pope can’t fulfill his duties, who steps in?

When a pope dies – or resigns, like Benedict XVI did in 2013 – the governance of the Catholic Church formally falls to the College of Cardinals. However, the authority of the college is very limited. On their own, cardinals cannot make any significant decisions concerning faith, morals and worship. Nor can they undo previous papal decisions or change church laws about electing a new pope.

All the heads of the dicasteries lose their office upon the death or resignation of a pope. The College of Cardinals serves as a caretaker government whose primary purpose is to prepare for the election of the new pope and oversee day-to-day workings of the Vatican.

One cardinal, known as the “camerlengo,” is responsible for confirming the pope’s death or resignation. He then assumes control over the pope’s residence and coordinates the funeral, if needed. The camerlengo also takes custody of the Vatican’s property in Rome and supervises details for the upcoming conclave.

A man wearing a priest's collar gestures as he speaks, sitting in front of a framed portrait of Pope Francis.
Cardinal Camerlengo Kevin Farrell talks with The Associated Press in his office in Rome in 2018.
AP Photo/Paolo Santalucia

The day-to-day business of the Catholic Church continues, but no big decisions can be made in the absence of a pope. The church cannot appoint new bishops, and the Vatican cannot start new diplomatic efforts.

Are officials at the Vatican often nominated to be pope?

Sometimes. Francis was a cardinal from Argentina before his election as pope and had not served in the Roman Curia. However, Benedict XVI, Francis’ predecessor, did serve as the prefect of the Congregation – now called Dicastery – for the Doctrine of the Faith. Some recent popes served in the Curia earlier in their career but not immediately before their election.

What do you wish more people understood about the Vatican?

Three things. First, the Vatican is unlike any organization in the world. Its religious mission and political status rest on nearly 2,000 years of history. This complicated story provides a unique tradition that anchors the institution of the Catholic Church, but can also block the church from critical self-examination and renewal.

Second, the Vatican is like every organization in the world. Vatican officials can be faithful to the highest standards of their religion, truly wishing to serve the church and the common good of humanity. But they can also be flagrantly immoral, even criminals, and careerist seekers of status or luxury. Francis has consistently called out priests and bishops who see themselves as somehow superior by virtue of their office or their ordination.

Finally, compared with the massive bureaucracies of modern governments and corporations, the Vatican is relatively small and not as wealthy as it is often portrayed.

Although the Curia manages a vast international organization, its resources are far closer to my own midsize Catholic university than to the U.S. government or Apple. Vatican City and the Holy See employ about 2,000 people, with an operating budget of about US$835 million.

Yes, the Catholic Church has wealth – and the ongoing problem of deficits and financial corruption. But the Vatican’s resources pale in comparison with what a modern state or large company can muster.The Conversation

Daniel Speed Thompson, Associate Professor of Religious Studies, University of Dayton

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

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Coastal economies rely on NOAA, from Maine to Florida, Texas and Alaska – even if they don’t realize it

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theconversation.com – Christine Keiner, Chair, Department of Science, Technology, and Society, Rochester Institute of Technology – 2025-02-28 07:46:00

Coastal economies rely on NOAA, from Maine to Florida, Texas and Alaska – even if they don’t realize it

U.S. fishing industries, both commercial and recreational, rely on healthy coastal areas.
Wolfgang Kaehler/LightRocket via Getty Images

Christine Keiner, Rochester Institute of Technology

Healthy coastal ecosystems play crucial roles in the U.S. economy, from supporting multibillion-dollar fisheries and tourism industries to protecting coastlines from storms.

They’re also difficult to manage, requiring specialized knowledge and technology.

That’s why the National Oceanic and Atmospheric Administration – the federal agency best known for collecting and analyzing the data that make weather forecasts and warnings possible – leads most of the government’s work on ocean and coastal health, as well as research into the growing risks posed by climate change.

The government estimates that NOAA’s projects and services support more than one-third of the nation’s gross domestic product. Yet, this is one of the agencies that the Trump administration has targeted, with discussions of trying to privatize NOAA’s forecasting operations and disband its crucial climate change research.

As a marine environmental historian who studies relationships among scientists, fishermen and environmentalists, I have seen how NOAA’s work affects American livelihoods, coastal health and the U.S. economy.

Here are a few examples from just NOAA’s coastal work, and what it means to fishing industries and coastal states.

Preventing fisheries from collapsing

One of the oldest divisions within NOAA is the National Marine Fisheries Service, known as NOAA Fisheries. It dates to 1871, when Congress created the U.S. Commission of Fish and Fisheries. At that time, the first generation of conservationists started to worry that America’s natural resources were finite.

By conducting surveys and interviewing fishermen and seafood dealers, the fish commissioners discovered that freshwater and saltwater fisheries across the country were declining.

YouTube video
Looking back on 150 years of NOAA’s fisheries history.

Oil spills and raw sewage were polluting waterways. Fishermen were using high-tech gear, such as pound nets, to catch more and more of the most valuable fish. In some areas, overfishing was putting the future of the fisheries in jeopardy.

One solution was to promote aquaculture, also known as fish or shellfish farming. Scientists and entrepreneurs reared baby fish in hatcheries and transferred them to rivers, lakes or bays. The Fish Commission even used refrigerated railroad cars to ship fish eggs across the country.

Today, U.S. aquaculture is a US$1.5 billion industry and the world’s fastest-growing food sector. Much of the salmon you see in grocery stores started as farm-raised hatchlings. NOAA provides training, grants and regional data to support the industry.

Men stand in line with pails to deposit them in a train car on a siding.
Men carry pails of fish specimens to a U.S. Fish Commission ‘fish car’ – a train car designed specifically for transporting fish or fish eggs to stock U.S. rivers, lakes and coastal waters – in this historical photo.
Smithsonian Institution Archives

NOAA Fisheries also helps to regulate commercial and recreational fishing to keep fish populations healthy and prevent them from crashing.

The 1976 Magnuson-Stevens Fishery Conservation and Management Act and other laws implemented catch limits to prevent overfishing. To develop fair regulations and combat illegal practices, NOAA and its predecessors have worked with fishing organizations through regional fishery management councils for decades.

These industries generate $321 billion in sales and support 2.3 million jobs.

Restoring coral reefs to help marine life thrive

NOAA also benefits U.S. coastal communities by restoring coral reefs.

Corals build up reefs over centuries, creating “cities of the sea.” When they’re healthy, they provide nurseries that protect valuable fish species, like snapper, from predators. Reefs also attract tourism and protect coastlines by breaking up waves that cause storm-driven flooding and erosion.

The corals of Hawaii, Florida, Puerto Rico and other tropical areas provide over $3 billion a year in benefits – from sustaining marine ecosystems to recreation, including sport fishing.

However, reefs are vulnerable to pollution, acidification, heat stress and other damage. Warming water can cause coral bleaching events, as the world saw in 2023 and 2024.

NOAA monitors reef health. It also works with innovative restoration strategies, such as breeding strains of coral that resist bleaching, so reefs have a better chance of surviving as the planet warms.

Battling invasive species in the Great Lakes

A third important aspect of NOAA’s coastal work involves controlling invasive species in America’s waters, including those that have menaced the Great Lakes.

Zebra and quagga mussels, spiny water flea and dozens of other Eurasian organisms colonized the Great Lakes starting in the late 1900s after arriving in ballast water from transoceanic ships. These invaders have disrupted the Great Lakes food web and clogged cities’ water intake systems, causing at least $138 million in damage per year.

Hoses on a boat covered in zebra mussels.
Zebra mussels found attached to this boat at an inspection station in Oregon show how easily invasive species can be moved. The boat had come from Texas and was on its way to Canada.
Oregon Department of Fish & Wildlife, CC BY-SA

In the Northwest Atlantic, Caribbean and Gulf of Mexico, invasive lionfish, native to Asia and Australia, have spread, preying on native fish essential to coral reefs. Lionfish have become one of the world’s most damaging marine fish invasions.

NOAA works with the Coast Guard, U.S. Geological Survey and other organizations to prevent the spread of invasive aquatic species. Stronger ballast water regulations developed through the agency’s research have helped prevent new invasions in the Great Lakes.

Understanding climate change

One of NOAA’s most crucial roles is its leadership in global research into understanding the causes and effects of climate change.

The oil industry has known for decades that greenhouse gases released into the atmosphere from burning fossil fuels would raise global temperatures.

Evidence and research from around the world have connected greenhouse gas emissions from human activities to climate change. The data have shown how rising temperatures have increased risks for coastal areas, including worsening heat waves and ocean acidification that harm marine life; raising sea levels, which threaten coastal communities with tidal flooding and higher storm surges; and contributing to more extreme storms.

NOAA conducts U.S. climate research and coordinates international climate research efforts, as well as producing the data and analysis for weather forecasting that coastal states rely on.

Why tear apart an irreplaceable resource?

When Republican President Richard Nixon proposed consolidating several different agencies into NOAA in 1970, he told Congress that doing so would promote “better protection of life and property from natural hazards,” “better understanding of the total environment” and “exploration and development leading to the intelligent use of our marine resources.”

The Trump administration is instead discussing tearing down NOAA. The administration has been erasing mentions of climate change from government research, websites and policies – despite the rising risks to communities across the nation. The next federal budget is likely to slash NOAA’s funding.

Commercial meteorologists argue that much of NOAA’s weather data and forecasting, also crucial to coastal areas, couldn’t be duplicated by the private sector.

As NOAA marks its 55th year, I believe it’s in the nation’s and the U.S. economy’s best interest to strengthen rather than dismantle this vital agency.The Conversation

Christine Keiner, Chair, Department of Science, Technology, and Society, Rochester Institute of Technology

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

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As flu cases break records this year, vaccine rates are declining, particularly for children and 65+ adults

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theconversation.com – Annette Regan, Adjunct Associate Professor of Epidemiology, University of California, Los Angeles – 2025-02-28 07:46:00

As flu cases break records this year, vaccine rates are declining, particularly for children and 65+ adults

It’s not too late to get a flu shot.
Fat Camera/E+ via Getty Images

Annette Regan, University of California, Los Angeles

In February 2025, flu rates spiked to the highest levels seen in at least 15 years, with flu outpacing COVID-19 infections and hospitalizations for the first time since the beginning of the COVID-19 pandemic. The Centers for Disease Control and Prevention has classified this flu season as having “high” severity across the U.S.

The Conversation asked epidemiologist Annette Regan to explain why this flu season is different from last year’s and what people can do to help reduce the spread.

How do flu cases and hospitalizations this year compare with previous years?

Beginning in late January and extending through February 2025, flu hospitalizations have been higher than any other week since before 2009.

Most flu cases appear to be from influenza A strains, with a split between influenza A/H3N2 and influenza A/H1N1. These are two different subtypes of the influenza A virus.

Researchers believe that historically seasons that are predominated by influenza A/H3N2 infections tend to be more severe, but infections from influenza A/H1N1 can still be very severe.

This year’s season is also peaking “late” compared with the past three flu seasons, which peaked in early or late December.

Unfortunately, there have been a number of deaths from flu too this season. Since Jan. 1, 2025, alone, over 4,000 people, including 68 children, have died from flu. While the number of deaths do not mark a record number, it shows that flu can be a serious illness, even in children.

YouTube video
Unless directed otherwise, everyone ages 6 months and older should get a flu shot.

Why are flu cases so high this year?

There are a number of factors behind any severe season, including poor community protection from low immunization rates and low natural immunity, virus characteristics, vaccine effectiveness and increased human contact via travel, office work or schools.

Unfortunately, flu vaccination rates have declined since the COVID-19 pandemic. At the end of the 2023-24 flu season, 9.2 million fewer doses were administered in pharmacies and doctors’ offices compared with an average year before the pandemic.

In addition, since 2022, fewer and fewer doses of flu vaccine have been distributed by private manufacturers. Flu vaccination rates for adults have historically been in the 30% to 60% range, much lower than the recommended 70%. Before the COVID-19 pandemic, flu vaccination rates were increasing by around 1% to 2% every year.

Flu vaccination rates began dropping after the COVID-19 pandemic, especially in higher-risk groups. Flu vaccination in children has dropped from 59% in 2019-20 to 46% in 2024-25. In adults 65 years and older, the group with the greatest risk of hospitalization and death, flu vaccination rates dropped from 52% in 2019-20 to 43% in 2024-25.

Lower vaccination rates mean a greater portion of the population is not protected by vaccines. Data shows that vaccination reduces the risk of flu hospitalization. Even if a vaccinated person gets infected, they may be less likely to experience severe illness. As a result, low vaccination rates could contribute to higher flu severity this season.

However, low vaccination rates are probably not the only reason for the high rates of flu this season. In previous severe seasons, genetic changes to the viruses have made them better at infecting people and more likely to cause severe illness.

The effectiveness of annual flu vaccines varies depending on how well the vaccine matches the circulating virus. The effectiveness of vaccines ranges from 19% to 60% in any given season. In the 2023-24 flu season, the vaccine was 42% effective.

Similarly, early 2024-25 data from the U.S. shows that the vaccine was 41% to 55% effective against flu hospitalizations in adults and 63% to 78% effective against flu hospitalizations in children.

YouTube video
Something as simple as regular handwashing could keep you from getting the flu.

How do seasonal flu symptoms differ from COVID-19 and other illnesses?

It’s important to remember that people often incorrectly refer to “the flu” when they have a common cold. Flu is caused only by the influenza virus, which tends to be more severe than common colds and more commonly causes a fever.

Many of the signs and symptoms for flu, COVID-19 and other respiratory viruses are the same and can range from mild coldlike symptoms to pneumonia and respiratory distress. Common flu symptoms are fever, cough and fatigue, and may also include shortness of breath, a sore throat, nasal congestion, muscle aches and headache.

Some symptoms, such as changes in or loss of taste and smell, are more common for COVID-19. For both COVID-19 and flu, the symptoms do not start until about one to four days after infection, and symptoms seem to last longer for COVID-19.

The only way to know what virus is causing an infection is to test. This can be done using a rapid test, some of which now test for flu and COVID-19 together, or by seeing a doctor and getting tested using a nasal swab. There are prescription antiviral medications available to treat flu and COVID-19, but they need to be taken near the time that symptoms start.

Some people are at high risk of severe flu and COVID-19, such as those who are immunosuppressed, have diabetes or have chronic heart or lung conditions. In these cases, it is important to seek early care and treatment from a health care professional. Some doctors will also prescribe via telehealth calls, which can help reduce the strain on doctors’ offices, urgent care centers and emergency rooms when infection rates are high.

What can people do now to help steer clear of the flu?

There are a number of ways people can reduce their risk of getting or spreading flu. Since the flu season is still underway, it’s not too late to get a flu vaccine. Even in seasons when the vaccine’s effectiveness is low, it is likely to offer better protection compared with remaining unvaccinated.

Handwashing and disinfecting high-traffic surfaces can help reduce contact with the flu virus. Taking efforts to avoid contact with sick people can also help, including wearing a mask when in health care facilities.

Finally, remember to take care of yourself. Exercising, eating healthy and getting sufficient sleep all help support a healthy immune system, which can help reduce chances of infection.

Those who have been diagnosed with flu or are experiencing flu-like symptoms should avoid contact with other people, especially in crowded spaces. Covering coughs and sneezes can help reduce the amount of virus that is spread.The Conversation

Annette Regan, Adjunct Associate Professor of Epidemiology, University of California, Los Angeles

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

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