With frigid innovation, scientists make a new form of ice
The Hindu
Ordinary ice is crystalline in nature, with water molecules arranged in a regular pattern.
Using a device that might be described as a super-duper cocktail shaker, scientists have fashioned a previously unknown form of ice - one that might exist on our solar system's icy moons - in research that sheds light on water's behaviour under extreme conditions.
The researchers said they employed a process called ball milling to vigorously shake ordinary ice together with steel balls in a container cooled to minus-328 degrees Fahrenheit (minus-200 degrees Celsius). This yielded what they called "medium-density amorphous ice," or MDA, which looked like a fine white powder.
Ordinary ice is crystalline in nature, with water molecules - two hydrogen atoms and one oxygen atom, or H2O - arranged in a regular pattern. Amorphous ice's water molecules are in a disorganized form resembling a liquid.
"Ice is frozen water and contains H2O molecules. H2O is a highly versatile molecular building block that can form many different structures depending on temperature and pressure," said University College London professor of physical and materials chemistry Christoph Salzmann, senior author of the research published this week in the journal Science.
"Under pressure, the molecules pack more efficiently, which is why there are many different forms of ice," Salzmann added.
Virtually all ice on Earth exists in its familiar crystalline form - think of the ice cubes in your lemonade. But amorphous ice is by far the most common form of water in space. Scientists have identified 20 different forms of crystalline ice and three forms of amorphous ice - one low density (discovered in the 1930s), one high density (discovered in the 1980s) and the new one in between.
Amorphous ice on Earth may be confined to the atmosphere's frigid upper reaches.