DNA Crystals in Ice: Rewriting Water & Life?
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For decades, scientists believed ice found throughout the universe was essentially frozen chaos – a disordered snapshot of liquid water. Now, groundbreaking research from University College London (UCL) and the University of cambridge challenges this assumption, revealing that even seemingly amorphous ice contains a surprising degree of hidden crystalline structure. This finding not only reshapes our understanding of water’s behavior in extreme environments but also has potential implications for advanced technologies here on Earth.
Rethinking Ice in the cosmos
“Ice on Earth is a cosmological curiosity due to our warm temperatures,” explains Dr. christopher Davies of UCL Chemistry. “You can see its ordered nature in the symmetry of a snowflake.” But the ice prevalent in interstellar space, forming on dust grains in vast molecular clouds, exists under drastically different conditions – incredibly cold temperatures and immense pressure.
Previously, this cosmic ice was thought to be entirely amorphous, lacking the long-range order characteristic of traditional crystalline ice. Researchers believed it was simply liquid water frozen in a disordered state. Though,the new study demonstrates that this isn’t the whole story.
Computer Simulations and Real-World Experiments Converge
The research team employed a two-pronged approach, combining elegant computer modeling with laboratory experiments. They utilized two computer models to simulate freezing water molecules at -120 degrees Celsius, varying the cooling rate to produce different proportions of crystalline and amorphous ice.
The simulations revealed a striking result: ice containing up to 20% crystalline structure closely mirrored the structure of low-density amorphous ice (LDA) observed in X-ray diffraction studies. Further simulations, creating densely packed ice crystals and then introducing disorder, yielded similar results, requiring only around 25% crystalline content.
To validate these findings, the team created real samples of LDA using methods mimicking those found in space – depositing water vapor onto extremely cold surfaces and warming up high-density amorphous ice (HDA), formed by compressing ordinary ice at frigid temperatures. By gently heating these samples, they observed variations in the proportion of molecules arranged in a six-fold (hexagonal) pattern, providing indirect evidence of underlying crystalline structures.
“If it was fully disordered, the ice would not retain any memory of its earlier forms,” the researchers explain. The observed retention of structural ’memory’ strongly suggests the presence of embedded crystals within the amorphous matrix.
Implications for Technology and Space Exploration
This discovery extends beyond cosmology, offering potential benefits for terrestrial technologies. Amorphous materials are crucial components in many advanced applications, including the glass fibers used for long-distance data transmission.
“If they do contain tiny crystals and we can remove them, this will improve their performance,” notes Dr. Davies. Understanding and controlling the crystalline content within amorphous materials could lead to important advancements in material science.
Furthermore, the research highlights the potential of ice as a valuable resource in space. “Ice is potentially a high-performance material in space,” says Dr. Davies. ”It could shield spacecraft from radiation or provide fuel in the form of hydrogen and oxygen. So we need to know about its various forms and properties.”
A History of Amorphous Ice and Future Questions
Scientists first discovered low-density amorphous ice in the 1930s, and its high-density counterpart was identified in the 1980s. More recently, in 2023, the same UCL and Cambridge team discovered medium-density amorphous ice, which possesses the same density as liquid water – meaning it would neither sink nor float.
Despite these advances, many questions remain. Researchers are now investigating whether the size of crystals within amorphous ice varies depending on its formation process, and whether a truly, completely amorphous ice is even possible.
As Professor Angelos michaelides of the University of Cambridge points out, ”Water is the foundation of life but we still do not fully understand it. Amorphous ices may hold the key to explaining some of water’s many anomalies.” This ongoing research promises to unlock further secrets of this seemingly simple, yet profoundly complex, substance.