New form of ‘exotic’ ice discovered

A new form of “exotic” icewhere similar in density and molecular structure to liquid water more than any other known type of ice, scientists in Britain have discovered, which may lead to a better understanding of water and its many “anomalies”. Furthermore, the new type of ice is likely to exist on distant icy moons of our solar system, such as Ganymede and Europa.

The hitherto unknown ice is amorphous, that is, its molecules do not have an organized crystalline form like ordinary ice. THE amorphous icealthough rare on Earth, is the main form of ice in space because, due to the colder environment there, ice does not have enough thermal energy to form crystals.

The researchers from University College London (UCL) and the University of Cambridge, led by Chemistry professors Christoph Saltzman and Angelos Michaelidis, who made the relevant publication in the journal “Science,” they named the new ice “medium density amorphous ice” (MDA) and found that, unlike other known ices, it has about the same density as liquid water. Its density is 1.06 grams per cubic centimeter, while water has a density of 1 gram per cubic centimeter.

Scientists estimate that the MDA ice, which looks like a fine white powder, may exist inside icy moons of Jupiter and Saturn. In fact, it was found that when said ice heats up and crystallizes, releasing very large amounts of heatwhich could trigger tectonic movements and icequakes on frozen satellites.

Dr. Saltzman stated that “water is the foundation of all life. Our existence depends on it, we launch space missions in search of it, yet scientifically our understanding of it is limited. We know of 20 crystalline forms of ice, though only two basic types of amorphous ice had previously been discovered, one high and one low density. There was a huge density gap between them, and until now it was accepted that there is no intermediate form. Our study shows that amorphous medium-density ice comes to fill exactly this density gap.”

The wateras reported by APE-MPE, has many oddities and anomalies that have puzzled scientists for a long time. Normally, when it freezes, it acquires a crystalline structure, as its molecules are arranged in hexagons, thus creating solid ice. But ice is less dense than liquid water, an unusual property for crystals.

Water is most dense at 4 degrees Celsius and becomes less dense as it freezes, hence ice floats. Also, the more liquid water is compressed, the easier it becomes to compress, unlike most other substances.

THE low-density amorphous ice was first discovered in the 1930s, when scientists compressed water vapor onto a metal surface that had been cooled to -110 degrees Celsius. High-density amorphous ice was discovered in the 1980s when normal ice was compressed to nearly -200 degrees Celsius.

The new medium-density ice was discovered when normal ice with a hexagonal crystal form was pulverized and cooled to -196 degrees in a container of metal pellets. At some point the new MDA ice appeared as grains stuck to the metal balls. Its molecular structure is chaotic, resembling that of glass. When said amorphous ice is heated to -120 degrees Celsius, then it becomes crystalline again and releases a lot of heat.

On Earth in general amorphous ice is thought to exist only in the upper and colder layers of the atmosphere. In space, amorphous ice abounds. Comets e.g. they are essentially large chunks of low-density amorphous ice.