Using ultracold temperatures and some steel ball bearings, scientists have created a brand-new, bizarre form of ice that has the same density of liquid water.
The ice, known as medium-density amorphous ice, fits into a gap in the annals of frozen water that scientists weren’t sure would ever be filled. Unlike the crystalline ice that forms naturally on Earth, the newly created ice doesn’t have an organized molecular structure. Instead, its molecules are in a chaotic mismatch, more like glass — a state known as amorphous. Other types of amorphous ice have been made before, but they’ve been either much less dense or far denser than liquid water. This new Goldilocks version of amorphous ice is right in the middle, almost exactly matching liquid water’s density, researchers explained in a new study published in the journal Science today (Feb. 2).
“It’s something completely new,” said study senior author Christoph Salzmann (opens in new tab) , a professor of physical and materials chemistry at University College London.Grinding ice
When ice freezes normally on Earth, its molecules stack into an organized crystalline structure. This crystalline ice is one of the weird quirks of H2O, because it floats on liquid water in its solid state rather than sinking. This is due to the relatively big gaps in the crystal structure of water ice, compared with other materials that form denser structures when they crystallize.
When properly manipulated, though, liquid water can also freeze in a disorganized, amorphous state. The first of these states, low-density amorphous ice, was discovered in the 1930s. It’s made by depositing water vapor on very cold surfaces. This process happens naturally in space, Salzmann said, so low-density amorphous ice may be the most common form of ice in the universe.
In the 1980s, researchers discovered that they could also make high-density amorphous ice by compressing regular ice at very low temperatures. But no one ever had ever made amorphous ice with a medium density — that is, until Salzmann and his colleagues had a “crazy Friday afternoon idea.” They decided to try ball milling ice.
A ball mill is a device kind of like a very advanced cocktail shaker. A material is put into a chamber with stainless-steel balls and shaken or turned until the material is ground up. Ball milling is used in many industries, but it’s particularly good at creating amorphous materials and at grinding soft, frozen materials into powders, Salzmann said.
“We said, ‘Why don’t we ball mill ice and see what happens?'” Salzmann said.Weird properties
The researchers expected that the ball mill would just break the ice crystals into smaller ice crystals. But that’s not what happened. Instead, the tumbling steel balls sheared and compressed the ice crystals, shoving them into a new state of disorganization. The result? Medium-density amorphous ice.
Computer modeling showed that the ice starts in a nice, crystalline state, its hydrogen bonds forming a hexagonal lattice. The random shearing from the ball-milling pushes these hydrogen bonds this way and that, leaving them pointing up and down in a chaotic zigzag.
The new form of ice forms at 77 kelvins, or minus 321 degrees Fahrenheit (minus 196 degrees Celsius). It has some odd properties beyond its density of 1.06 grams per cubic centimeter (0.037 ounces per 0.06 cubic inches).. (Water has a density of 1 gram per cubic centimeter, or 0.035 punches per 0.06 cubic inches.) Among them, Salzmann said, is that when the researchers compressed the medium-density ice and heated it to minus 185 F (minus 120 C), the ice recrystallized, releasing a large amount of heat.
“With other forms of [amorphous] ice, if you compress them and you release the pressure, it’s like nothing happened,” Salzmann said. “But the MDA [medium-density amorphous ice] somehow has this ability to store the mechanical energy and release it through heating.”Related stories—Why is water important?
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Medium-density amorphous ice might occur naturally on the ice moons of gas giant planets, Salzmann said, where the gravitational forces of the enormous worlds compress and shear the moons’ ice. If so, the mechanical energy stored in this form of ice could influence the tectonics on these Hoth-like moons.
Understanding medium-density amorphous ice could also help researchers understand liquid water better more generally, Salzmann said. Water is odd not only because its crystalline form floats but also because it has other unique properties, like high surface tension and high melting and boiling points. Scientists still debate the nature of water at extremely low temperatures. Any debate now needs to take into account medium-density amorphous ice, Salzmann said.
“A lot of our understanding of liquid water was built on the pillars that there is low-density and high-density amorphous ice,” he said. “How does the medium-density amorphous ice fit into that picture?”
Donald Trump’s Middle East envoy has met Israel’s prime minister in an effort to secure a ceasefire deal in Gaza before the president-elect takes office on 20 January.
Benjamin Netanyahu’s office confirmed details of the meeting with Steve Witkoff on Saturday, adding that the head of the Israeli Mossad intelligence agency has been deployed to Qatar in order to “advance” talks.
It was not immediately clear when David Barnea would travel to Doha for the latest round of indirect discussions between Israel and Hamas.
Earlier on Saturday, an Israeli official said some progress had been made, mediated by Egypt, Qatar and the United States, to reach a deal in Gaza.
The mediators are making renewed efforts to halt fighting in Gaza and free the remaining Israeli hostages held there before Mr Trump takes office.
A deal would also involve the release of some Palestinian prisoners held in Israeli jails.
Families of Israeli hostages welcomed Mr Netanyahu’s decision to dispatch the officials, with the Hostages and Missing Families Forum Headquarters describing it as a “historic opportunity”.
Mr Witkoff arrived in Doha on Friday and met the Qatari Prime Minister Sheikh Mohammed bin Abdulrahman Al Thani, Qatar’s foreign ministry said.
Egyptian and Qatari mediators received reassurances from Mr Witkoff that the US would continue to work towards a fair deal to end the war soon, Egyptian security sources said, though no further details were released.
Israel launched its assault on Gaza after Hamas fighters stormed across its borders in October 2023, killing 1,200 people and taking more than 250 hostages, according to Israeli figures.
Families of the roughly 100 hostages still held in Gaza are pressing Mr Netanyahu to reach a deal to bring their loved ones home.
Since then, more than 46,000 people have been killed in Gaza, according to Palestinian health officials, with much of the area destroyed and gripped by a humanitarian crisis, with most of its population displaced.
Pope Francis has been honoured with America’s highest civilian award by President Joe Biden, who has described the pontiff as “a light of faith, hope, and love that shines brightly across the world”.
It is the first time Mr Biden, 82, has given the Presidential Medal of Freedom with Distinction during his four years in office.
In a statement, the White House said the award is “presented to individuals who have made exemplary contributions to the prosperity, values, or security of the United States, world peace, or other significant societal, public or private endeavours”.
Mr Biden had been scheduled to present the medal to Pope Francis, 88, in person on Saturday in Rome on what was to be the final overseas trip of his presidency. But the president cancelled his visit to monitor the California wildfires.
The White House said Mr Biden bestowed the award during a phone call in which they also discussed efforts to promote peace and alleviate suffering around the world.
The award can be presented with or without distinction.
Mr Biden presented the medal of freedom – without distinction – on 5 January to several people including fellow Democrat Hillary Clinton, humanitarian and U2 singer Bono, fashion designer Ralph Lauren and actors Michael J Fox and Denzel Washington.
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Mr Biden himself is a recipient of the award with distinction, recognised when he was vice president by then president Barack Obama in a surprise ceremony eight years ago.
The citation for the pope’s honour said his “mission of serving the poor has never ceased”.
“A loving pastor, he joyfully answers children’s questions about God. A challenging teacher, he commands us to fight for peace and protect the planet. A welcoming leader, he reaches out to different faiths,” it added.
And so now it is certain. Alice Weidel will lead her far-right party into Germany’s general election next month.
She was overwhelmingly backed at the Alternative for Germany (AfD) conference and was greeted with a standing ovation.
Weidel will fight the election with a manifesto that follows a familiar pattern from other successful populist campaigns in Europe and beyond – contempt for mainstream politicians, anger over levels of irregular immigration, a desire to rein in the power of the European Union and dismay over the spread of so-called woke values.
“Thank you for your trust,” she told the audience.
“I am excited to lead our campaign. For our people, for our future.”
Who is Weidel?
Weidel is an unusual figure to lead a German hard right-wing party – a gay woman with a PhD in economics, a Sri Lankan partner, two children and a home in another country – she commutes from Switzerland.
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Admittedly there is an awkward history – her grandfather was a Nazi judge appointed to the job personally by Adolf Hitler, but she has maintained that she did not know that fact growing up and has angrily distanced herself from accusations of racism.
Indeed, Ms Weidel maintains that her party is not on the far right, but is simply conservative.
And that is part of her attraction – she is perceived as uncompromising on the things that the AfD’s supporters hold dear – migration, Euroscepticism, the greatness of German culture – but she’s also perceived as more palatable to the wider public.
Or, at least, that’s the idea.
Thousands of protesters
Outside the sports centre, where the AfD’s convention was being held, thousands of protesters gathered to raise their fears that the country was going back to the politics of the past.
“They are fascists,” said a man called Gabriel, who was helping to blockade the road that ran past the venue.
“I don’t know if we have learnt anything in the past hundred years but now we do have to stand against fascism.”
Many of the delegates would angrily decry that label.
His grouping, Der Flugel, was declared a suspected extremist organisation but he remained the party’s leader in Thuringia.
In 2019, a court ruled that it was not libellous to refer to Hocke as a fascist.
He has twice been found guilty of using Nazi slogans but last year, under his leadership, the AfD won the state election.
Emotions often run high when the AfD is involved. The protests here were, at times, heated.
Police had to clear the road in front of Ms Weidel’s car as some protesters sat down and others began to surround it.
Later, the party’s MPs were called to gather together for a sudden security briefing.
The sports centre where this meeting was held once hosted the World Sumo Wrestling Championship.
Here, the heavyweights were political, and the prize at stake was far more consequential.
Barring a quite astonishing movement in the polls, the AfD is unlikely to win the election next month, but the party may well come second with more than 20% of the vote.
That probably won’t equate to power – Germany’s major parties have all said they won’t go into coalition with the AfD – but it will mean momentum.
It will mean a loud voice in the Bundestag, the German federal parliament, and the ability to pressure the next chancellor into reflecting the opinions of the millions who vote for Ms Weidel’s vision.
Long term, if Ms Weidel can prove that her party is palatable, as well as popular, then she knows the political dam will one day break.
If enough people back the AfD, it will eventually become impossible to shun the party forever.