Physicists Discover the Most Complex Forms of Ice Yet

Recommendable! The many wonders of water!

"... Since 1900, scientists have observed more than 20 phases of ice, many of them shaped under extreme conditions. The growing list includes hot ice and even ice that conducts electricity. ...

Over the past decade, computer simulations have predicted tens of thousands of possible forms of ice. Though uncommon on our planet, exotic ice may exist in off-Earth environments, from cold and amorphous comet tails to the hot and crushing cores of icy planets.

As physicists put water to the test with improved experimental techniques, they keep finding surprises. “You take water, and just the way you compress it — a little bit faster, a bit slower, up and down, at the right timescale — and then you can find this completely unexpected behavior,” ...

In 2018, an international research group from Europe and Japan created an ambitious computer simulation of the dynamics of water molecules that aimed to predict undiscovered forms of ice. The result was a catalog of over 75,000 phases, each characterized by a slightly different way that the water molecules could fit together when subjected to a different combination of temperature and pressure. ...

In 2025, Bove’s team in Lausanne discovered a smaller but in some ways stranger metastable phase of ice. In a study published in Nature, they reported the first observation of plastic ice VII. This is a variation of ice VII, a high-pressure phase of ice, that appears when the ice is heated to around 500 degrees Celsius. ..."

Physicists Discover the Most Complex Forms of Ice Yet | Quanta Magazine "Scientists keep detecting new forms of ice. According to simulations, there could be many more left to find."

Fig. 1: Phase diagram of the QENS experiment and investigated thermodynamic paths.

a, Experimental phase diagram of water in the investigated P–T region, melting lines are reproduced from refs. 31,43. The region of stability of plastic ice VII from numerical simulations8 is shown with white dashed lines, pressures and temperatures are shifted to match the experimental melting line. The measured thermodynamic points are represented as circles with colours corresponding to the phase attribution (a selection of thermodynamic points from previous experiments34 are represented as squares). Error bars on the pressure determination are of ±0.5 GPa for the high-pressure isobars, whereas they are of 0.1 GPa for the thermodynamic points close to the melting as the melting was used to calibrate the pressure. 

Scientists claim to have found evidence of a liquid-liquid critical point in supercooled water

Amazing stuff! The many wonders of water!

"Despite being the most familiar liquid, water is weird. It breaks many of the usual rules that govern the liquid state. In 1992 a team of researchers suggested why that is. Perhaps, they said, there are two types of liquid water, which become distinct only at temperatures well below freezing point, where it’s all but impossible to keep water liquid. Researchers have sought evidence for this bold conjecture ever since – and now an international team claims to have found it.

Water is weird. It has over 60 properties that mark it as rather different to other liquids, such as high surface tension, high boiling point and low compressibility. Is it because liquid water is better thought of as two different liquids? ...

used ultrafast laser pulses to rapidly melt ice at temperatures and pressures close to those at which the two deeply supercooled liquid phases of water are thought to exist. They then used x-ray scattering to see a signature of the two liquids and the liquid–liquid phase transition between them – an abrupt (first-order) transition that, like the transition between a normal liquid and gas phase, ends in a critical point where the two phases become indistinguishable. ..."

"Using x-ray lasers, researchers at Stockholm University have been able to determine the existence of a critical point in supercooled water at around -63 °C and 1000 atmosphere. Ordinary water at higher temperatures and lower pressures is strongly affected by the presence of this critical point, causing the origin of its strange properties. ..."

From the editor's summary and abstract:

"Editor’s summary

Polyamorphism and the resulting liquid-liquid critical point (LLCP) in supercooled water are intriguing phenomena in condensed-matter science. Rapid spontaneous ice formation that the water can undergo when probed makes finding the LLCP extremely challenging experimentally.

Previously, evidence for polyamorphism relied on indirect signs such as extrapolating unusual physical properties, the presence of two amorphous ice forms, and liquid-liquid transitions in simulations.

Experiments presented by You et al. with isochoric heating of high- and low-density amorphous ices using infrared ultrafast laser pulses followed by x-ray scattering at time scales before ice formation have directly and convincingly demonstrated two liquid states near a critical point in supercooled water ...

Abstract

The search for the liquid-liquid critical point in supercooled water is challenging owing to rapid crystallization. We studied supercooled water at timescales before ice formation by heating high- and low-density amorphous ices using infrared ultrafast laser pulses, followed by x-ray scattering.

By varying the pump laser fluence, we accessed liquid states straddling the predicted critical point. We observed a crossover from a discontinuous to a continuous transition at which broad and slow structural variations occurred, consistent with critical fluctuations and slowing down.

We also observed a rapid increase in the heat capacity indicating a critical divergence at 210 ± 8 K coincident with enhanced density fluctuations. These results suggest that our experiments have directly probed the vicinity of a critical point in supercooled water."

Scientists claim to have found the two types of water that explain the liquid’s oddness | Research | Chemistry World

Experimental Discovery of a New Critical Point in Water (original news release)

Experimental evidence of a liquid-liquid critical point in supercooled water (no public access)

When raindrops turn into rolling sandballs

Amazing stuff!

We still do not even understand water very well, but numerous scientists and demagogues claim anthropogenic climate change/global warming like charlatans! Medieval superstition still continuous at the end of the first quarter of the 21st century!

"Discovery suggests raindrops can be up to 100 times more erosive than once thought"

"When a raindrop hits the ground, it explodes like a tiny bomb, carving out a tiny crater that sends soil and sand grains flying. Now, scientists report a previously unknown—and even more erosive—behavior. Under certain conditions, raindrops can bounce and then roll down a slope, picking up sand as they go ... The sand-covered balls transport up to 100 times more sediment downhill than drops that don’t roll, a fact that could help make more realistic computer models of soil erosion and land change. ..."

From the significance and abstract:

"Significance

Raindrops do not just splash—they can roll, gather, and grow. While erosion is often thought to begin and end the moment a raindrop hits the ground, we found that the story continues: On sloped, dry soil, raindrops can roll downhill like tiny snowballs, picking up grains along the way and forming what we call “sandballs.” This process greatly amplifies the amount of soil a single drop can move—by up to ten times—revealing a powerful and previously overlooked erosion mechanism. Understanding how water and soil interact at this scale can help improve models of landscape change, soil loss, and agriculture. It may also inspire innovations in fields like bioengineering, food processing, and snow and soft matter physics.

Abstract

In the water cycle, erosion begins with the entrainment of soil by raindrops. The discrete, discontinuous, and three-phase nature of raindrop erosion—at the boundary of fluid and granular mechanics—makes this problem particularly challenging, compared to better-studied sediment transport by river and wind currents.

Past research has emphasized particle entrainment by raindrop splash at impact. Here, we report lab and field observations, that uncover a surprisingly rich and efficient postimpact phase. Raindrops impacting a dry, sloping, granular bed spontaneously form “sandballs;” drops of dense suspensions that can grow in mass to a jammed state by sediment entrainment, as they roll downhill like snowballs and magnify soil erosion.

Careful control of drop conditions reveals two stable sandball morphologies: peanut-like shapes linked to hydrodynamic instabilities and toroidal forms that undergo mechanical locking from extreme sediment loading, which have potential implications for related problems in bioengineering, pharmaceuticals, and snow physics."

Watch these raindrops turn into rolling ‘sandballs’ | Science | AAAS

Sandball genesis from raindrops (no public access)

Scientists simulate elusive liquid-liquid transition point using deep neural network

Amazing stuff! Still elusive! Still only computer simulation!

"A new Nature Physics study has shed light on the long-hypothesized liquid-liquid critical point where water simultaneously exists in two distinct liquid forms, opening new possibilities for experimental validation. ...

"One long-standing hypothesis suggests that under extreme conditions—specifically at very low temperatures and high pressures—water can exist in two distinct liquid phases: a high-density liquid and a low-density liquid." ...

When pure water is cooled to -38°C, it remains in liquid form despite passing its freezing point at 0°C. This is known as a supercooled state. ..."

From the abstract:

"The fascinating hypothesis that supercooled water may segregate into two distinct liquid phases, each with unique structures and densities, was first posited in 1992.

This idea, initially based on numerical analyses with the ST2 water-like empirical potential, challenged the conventional understanding of water’s phase behaviour at the time and has since intrigued the scientific community.

Over the past three decades, advancements in computational modelling—particularly through the advent of data-driven many-body potentials rigorously derived from first principles and augmented by the efficiency of neural networks—have greatly enhanced the accuracy of molecular simulations, enabling the exploration of the phase behaviour of water with unprecedented realism.

Our study leverages these computational advances to probe the elusive liquid–liquid transition in supercooled water.

Microsecond-long simulations with chemical accuracy, conducted over several years, provide compelling evidence that water indeed exists in two discernibly distinct liquid states at low temperature and high pressure.

By pinpointing a realistic estimate for the location of the liquid–liquid critical point at ~198 K and ~1,250 atm, our study not only advances the current understanding of water’s anomalous behaviour but also establishes a basis for experimental validation.

Importantly, our simulations indicate that the liquid–liquid critical point falls within temperature and pressure ranges that could potentially be experimentally probed in water nanodroplets, opening up the possibility for direct measurements."

Scientists map elusive liquid-liquid transition point using deep neural network

Constraints on the location of the liquid–liquid critical point in water (no public access)

Where did Earth's water come from? Not melted meteorites, according to scientists

Humans still do not even understand water or where it came from! I have blogged here about this subject (mystery of water) several times!

One more reason that Global Warming is a hoax and Climate Change is a religion!

"... A new study published in the journal Nature brings scientists one step closer to answering that question. ... researchers analyzed melted meteorites that had been floating around in space since the solar system's formation 4 1/2 billion years ago. They found that these meteorites had extremely low water content—in fact, they were among the driest extraterrestrial materials ever measured.
These results, which let researchers rule them out as the primary source of Earth's water, could have important implications for the search for water—and life—on other planets. It also helps researchers understand the unlikely conditions that aligned to make Earth a habitable planet. ..."

From the abstract:

"The timing of delivery and the types of body that contributed volatiles to the terrestrial planets remain highly debated. For example, it is unknown if differentiated bodies, such as that responsible for the Moon-forming giant impact, could have delivered substantial volatiles or if smaller, undifferentiated objects were more probable vehicles of water delivery. Here we show that the water contents of minerals in achondrite meteorites (mantles or crusts of differentiated planetesimals) from both the inner and outer portions of the early Solar System are ≤2 μg g−1 H2O. These are among the lowest values ever reported for extraterrestrial minerals. Our results demonstrate that differentiated planetesimals efficiently degassed before or during melting. This finding implies that substantial amounts of water could only have been delivered to Earth by means of unmelted material."

Where did Earth's water come from? Not melted meteorites, according to scientists

Degassing of early-formed planetesimals restricted water delivery to Earth (no public access)

Scientists made a new kind of ice that might exist on distant moons

We still know so little about water! But a lot of demagogues on a daily basis want us to believe in climate change! Water is still a mystery and we still make new discoveries about water (I reported here before under the label "science of water")!

"Scientists have created a new type of ice that matches the density and structure of water, perhaps opening a door to studying water’s mysterious properties.

“It might be liquid water frozen in time,” ...

The ice is called medium-density amorphous ice. The team that created it ... shook regular ice in a small container with centimetre-wide stainless-steel balls at temperatures of –200 ˚C to produce the variant, which has never been seen before. The ice appeared as a white granular powder that stuck to the metal balls. ...

Normally, when water freezes, it crystallizes and its molecules are arranged into the familiar hexagonal, solid structure that we call ice. Ice is less dense than its liquid form — an unusual property for a crystal. Depending on conditions such as pressure and the speed of freezing, water can also solidify in any of two dozen other regular arrangements. Amorphous ice is different: it has no such order. “You have lots of molecules joining on haphazardly,” says Chaplin.

Two types of amorphous ice have been previously discovered, both in the twentieth century. ‘Low-density’ amorphous ice is the result of water vapour freezing onto a very cold surface, at a temperature lower than –150 ˚C; ‘high-density’ amorphous ice forms by compressing ordinary ice at similar temperatures under high pressure. Although neither type is common on Earth, both are plentiful in space. “Comets are big chunks of low-density amorphous ice,” ..."

From the abstract:

"Amorphous ices govern a range of cosmological processes and are potentially key materials for explaining the anomalies of liquid water. A substantial density gap between low-density and high-density amorphous ice with liquid water in the middle is a cornerstone of our current understanding of water. However, we show that ball milling “ordinary” ice Ih at low temperature gives a structurally distinct medium-density amorphous ice (MDA) within this density gap. These results raise the possibility that MDA is the true glassy state of liquid water or alternatively a heavily sheared crystalline state. Notably, the compression of MDA at low temperature leads to a sharp increase of its recrystallization enthalpy, highlighting that H2O can be a high-energy geophysical material."

Scientists made a new kind of ice that might exist on distant moons The 'amorphous' solid is denser and could be water ‘frozen in time’.

Medium-density amorphous ice (no public access)

Milling ordinary ice with steel balls disrupted its crystalline structure and led to a novel, denser version of solid water.

Water can split into two different liquids and ties itself into knots when supercooled

Amazing stuff! Water ties itself into knots! What!

We still know so little about water! Another reason why the Global Warming Hoax and Climate Change Religion is propaganda and demagoguery!

"... By studying the behavior of water molecules placed under high pressure in temperature ranges that would usually cause the liquid to crystallize, the team identified the key features of two new liquid states of water. ...

When placed under high pressure at low temperature, the team explains, the H2O molecule takes on an unexpected shape: it ties itself into knots. This shift allows it to remain liquid even under conditions that would normally see it crystallizing into ice.

This research expands on theoretical work laid down in the 1990s that attempted to determine what interactions take place between supercooled water molecules — molecules that are taken below their typical freezing point without solidifying. ..."

From the abstract:

"The first-order phase transition between two tetrahedral networks of different density—introduced as a hypothesis to account for the anomalous behaviour of certain thermodynamic properties of deeply supercooled water—has received strong support from a growing body of work in recent years. Here we show that this liquid–liquid phase transition in tetrahedral networks can be described as a transition between an unentangled, low-density liquid and an entangled, high-density liquid, the latter containing an ensemble of topologically complex motifs. We first reveal this distinction in a rationally designed colloidal analogue of water. We show that this colloidal water model displays the well-known water thermodynamic anomalies as well as a liquid–liquid critical point. We then investigate water, employing two widely used molecular models, to demonstrate that there is also a clear topological distinction between its two supercooled liquid networks, thereby establishing the generality of this observation, which might have far-reaching implications for understanding liquid–liquid phase transitions in tetrahedral liquids."

Water can split into two different liquids when supercooled, researchers find The findings can help us better predict how water behaves in some extreme environments on alien planets.

Topological nature of the liquid–liquid phase transition in tetrahedral liquids (open access)

Fig. 3: Characterization of the LLPT in molecular water by identifying links and knots

Direct evidence emerges for the existence of two forms of liquid water

The magic of water! The latest research paper on this subject was even written by one researcher alone, very unusual!

Quick reminder: We don't yet even understand water fully, but Western societies are inundated on a daily basis with the pseudoscience and pretense of knowledge of Climate Change!

"Thirty years ago, a team working at Boston University made the dramatic suggestion that there are not one but two forms of liquid water, which can interconvert at high pressure well below water’s normal freezing point.1 Researchers have been searching for this putative liquid–liquid phase transition ever since, and evidence has slowly accumulated that it really exists. New experiments now supply what seems to be a direct observation of such a transformation between liquid states of different density – not in pure water but in solutions of the sugar trehalose. ..."

From the abstract:

"Water forms two glassy waters, low-density and high-density amorphs, which undergo a reversible polyamorphic transition with the change in pressure. The two glassy waters transform into the different liquids, low-density liquid (LDL) and high-density liquid (HDL), at high temperatures. It is predicted that the two liquid waters also undergo a liquid–liquid transition (LLT). However, the reversible LLT, particularly the LDL-to-HDL transition, has not been observed directly due to rapid crystallization. Here, I prepared a glassy dilute trehalose aqueous solution (0.020 molar fraction) without segregation and measured the isothermal volume change at 0.01 to 1.00 GPa below 160 K. The polyamorphic transition and the glass-to-liquid transition for the high-density and low-density solutions were examined, and the liquid region where both LDL and HDL existed was determined. The results show that the reversible polyamorphic transition induced by the pressure change above 140 K is the LLT. That is, the transition from LDL to HDL is observed. Moreover, the pressure hysteresis of LLT suggests strongly that the LLT has a first-order nature. The direct observation of the reversible LLT in the trehalose aqueous solution has implications for understanding not only the liquid–liquid critical point hypothesis of pure water but also the relation between aqueous solution and water polyamorphism."

Direct evidence emerges for the existence of two forms of liquid water | Research | Chemistry World

Direct observation of reversible liquid–liquid transition in a trehalose aqueous solution (no public access)

Supercooled water has been caught morphing between two forms

What little we still know about life's most essential substance! Notice, two different femtosecond lasers were used for these experiments!

This should also be a strong reminder that Global Warming is a hoax and Climate Change is a modern religion based on not much but medieval superstition!

"... When free from impurities, water can remain liquid below its typical freezing point of zero degrees Celsius, forming what’s called a supercooled liquid. But the dual nature of supercooled water was expected to appear in a temperature realm so difficult to study that it’s been dubbed “no-man’s-land.” Below around –40° C, water remains liquid for mere instants before it crystallizes into ice. Making the task even more daunting, the high-density phase appears only at very high pressures. ..."

"We prepared bulk samples of supercooled liquid water under pressure by isochoric heating of high-density amorphous ice to temperatures of 205 ± 10 kelvin, using an infrared femtosecond laser. Because the sample density is preserved during the ultrafast heating, we could estimate an initial internal pressure of 2.5 to 3.5 kilobar in the high-density liquid phase. After heating, the sample expanded rapidly, and we captured the resulting decompression process with femtosecond x-ray laser pulses at different pump-probe delay times. A discontinuous structural change occurred in which low-density liquid domains appeared and grew on time scales between 20 nanoseconds to 3 microseconds, whereas crystallization occurs on time scales of 3 to 50 microseconds. The dynamics of the two processes being separated by more than one order of magnitude provides support for a liquid-liquid transition in bulk supercooled water."

Supercooled water has been caught morphing between two forms | Science News The result could help explain some of the weird properties of H20

Here is the link to the respective research paper:

Experimental observation of the liquid-liquid transition in bulk supercooled water under pressure