A new crystalline form of water ice has been discovered in fleeting transitions between phases at high pressures.
, and it takes place as the substance slides between two already known, cubic arrangements of molecules. Although it's unlikely Ice-VIIwould naturally appear on Earth's surface, it could reveal more about how water behaves on massive alien worlds.compared to other liquids we know. The arrangement of molecules within water's frozen form – ice – can vary significantly, depending on the conditions around it.
The ice you see in the freezer, or falling from the sky as snowflakes or hailstones, is the most common natural ice on Earth. It is called Ice-I, with oxygen atoms arranged in a hexagonal grid. The structure is, however,When physicists cool Ice-I at various temperatures and apply different pressures to it, the hydrogen and oxygen atoms within can periodically reach different arrangements, sometimes even ordering themselves more neatly.
The researchers squeezed a sample of water in a diamond anvil, forcing it to freeze in a jumble of crystals. Lasers were used to then heat the sample, causing it to melt before re-freezing into what the researchers described as a powder-like collection of crystals. ; that is, 30,000 atmospheric pressures. According to the team's observations, the transition to Ice-VIIt occurs at around 5.1 gigapascals.Previous reports have put the transition pressure for Ice-X between 40 and 120 gigapascals. However, Grande and his team observed the transition between Ice-VIIThis, the team said, should help resolve the debate about the Ice-X transition pressure.