Category: English

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

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

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

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

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

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

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

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

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

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

Isolationism, then war

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

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

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

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

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

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

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

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

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

Alliance counters fascism

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

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

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

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

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

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

Postwar alliances

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Lightning on Mars

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

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

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

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

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

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

Releasing radio waves

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

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

Searching for Martian lightning

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

What makes one dielectric better than another?

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

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

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

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

The breakthrough that wasn’t

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

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

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

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

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

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

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

The culprit

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

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

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

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

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

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

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

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

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

Source: The Conversation – USA – By Robert A. Strong, Senior Fellow, Miller Center, University of Virginia

Now that the 2026 midterm elections are less than a year away, public interest in where things stand is on the rise. Of course, in a democracy no one knows the outcome of an election before it takes place, despite what the pollsters may predict.

Nevertheless, it is common for commentators and citizens to revisit old elections to learn what might be coming in the ones that lie ahead.

The historical lessons from modern midterm congressional elections are not favorable for Republicans today.

Most of the students I taught in American government classes for over 40 years knew that the party in control of the White House was likely to encounter setbacks in midterms. They usually did not know just how settled and solid that pattern was.

Since 1946, there have been 20 midterm elections. In 18 of them, the president’s party lost seats in the House of Representatives. That’s 90% of the midterm elections in the past 80 years.

Measured against that pattern, the odds that the Republicans will hold their slim House majority in 2026 are small. Another factor makes them smaller. When the sitting president is “underwater” – below 50% – in job approval polls, the likelihood of a bad midterm election result becomes a certainty. All the presidents since Harry S. Truman whose job approval was below 50% in the month before a midterm election lost seats in the House. All of them.

Even popular presidents – Dwight D. Eisenhower, in both of his terms; John F. Kennedy; Richard Nixon; Gerald Ford; Ronald Reagan in 1986; and George H. W. Bush – lost seats in midterm elections.

The list of unpopular presidents who lost House seats is even longer – Truman in 1946 and 1950, Lyndon B. Johnson in 1966, Jimmy Carter in 1978, Reagan in 1982, Bill Clinton in 1994, George W. Bush in 2006, Barack Obama in both 2010 and 2014, Donald Trump in 2018 and Joe Biden in 2022.

Exceptions are rare

There are only two cases in the past 80 years where the party of a sitting president won midterm seats in the House. Both involved special circumstances.

In 1998, Clinton was in the sixth year of his presidency and had good numbers for economic growth, declining interest rates and low unemployment. His average approval rating, according to Gallup, in his second term was 60.6%, the highest average achieved by any second-term president from Truman to Biden.

Moreover, the 1998 midterm elections took place in the midst of Clinton’s impeachment, when most Americans were simultaneously critical of the president’s personal behavior and convinced that that behavior did not merit removal from office. Good economic metrics and widespread concern that Republican impeachers were going too far led to modest gains for the Democrats in the 1998 midterm elections. The Democrats picked up five House seats.

The other exception to the rule of thumb that presidents suffer midterm losses was George W. Bush in 2002. Bush, narrowly elected in 2000, had a dramatic rise in popularity after the Sept. 11 attacks on the World Trade Center and the Pentagon. The nation rallied around the flag and the president, and Republicans won eight House seats in the 2002 midterm elections.

Those were the rare cases when a popular sitting president got positive House results in a midterm election. And the positive results were small.

Midterms matter

In the 20 midterm elections between 1946 and 2022, small changes in the House – a shift of less than 10 seats – occurred six times. Modest changes – between 11 and 39 seats – took place seven times. Big changes, so-called “wave elections” involving more than 40 seats, have happened seven times.

In every midterm election since 1946, at least five seats flipped from one party to the other. If the net result of the midterm elections in 2026 moved five seats from Republicans to Democrats, that would be enough to make Democrats the majority in the House.

In an era of close elections and narrow margins on Capitol Hill, midterms make a difference. The past five presidents – Clinton, Bush, Obama, Trump and Biden – entered office with their party in control of both houses of Congress. All five lost their party majority in the House or the Senate in their first two years in office.

Will that happen again in 2026?

The obvious prediction would be yes. But nothing in politics is set in stone. Between now and November 2026, redistricting will move the boundaries of a yet-to-be-determined number of congressional districts. That could make it harder to predict the likely results in 2026.

Unexpected events, or good performance in office, could move Trump’s job approval numbers above 50%. Republicans would still be likely to lose House seats in the 2026 midterms, but a popular president would raise the chances that they could hold their narrow majority.

And there are other possibilities. Perhaps 2026 will involve issues like those in recent presidential elections.

Close results could be followed by raucous recounts and court controversies of the kind that made Florida the focal point in the 2000 presidential election. Prominent public challenges to voting tallies and procedures, like those that followed Trump’s unsubstantiated claims of victory in 2020, would make matters worse.

The forthcoming midterms may not be like anything seen in recent congressional election cycles.

Democracy is never easy, and elections matter more than ever. Examining long-established patterns in midterm party performance makes citizens clear-eyed about what is likely to happen in the 2026 congressional elections. Thinking ahead about unusual challenges that might arise in close and consequential contests makes everyone better prepared for the hard work of maintaining a healthy democratic republic.

Robert A. Strong 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. For 80 years, the president’s party has almost always lost House seats in midterm elections, a pattern that makes the 2026 congressional outlook clear – https://theconversation.com/for-80-years-the-presidents-party-has-almost-always-lost-house-seats-in-midterm-elections-a-pattern-that-makes-the-2026-congressional-outlook-clear-271605