From the seas of Antarctica to the depths of your freezer, most ice on Earth is relatively tame stuff. But throughout the solar system and beyond, extreme temperatures and pressures can crush the frozen substance into increasingly odd varieties.
Last year, Millot, Coppari, and their colleagues found the first evidence for superionic ice, using diamond anvils and laser-induced shock waves to compress liquid water so much that it turned to solid ice for a few billionths of a second. The team’s measurements showed that the water ice briefly became hundreds of times more electrically conductive than it had previously been, a strong hint that it had gone superionic.
In their latest tests, the researchers used six giant laser beams to generate a sequence of shockwaves that crunched a thin layer of liquid water into solidified ice at millions of times Earth’s surface pressure and between 3,000 and 5,000 degrees Fahrenheit. Precisely timed x-ray flashes probed the configuration, which again only lasted for a few billionths of a second, and revealed that the oxygen atoms had indeed taken on a crystalline form.