Water as we've never known it: Physicists test water beyond Earth-like conditions

Water, as we know it on Earth, can undergo astonishing transformations when subjected to extreme conditions, such as those found on other planets. A groundbreaking study published in Communications Chemistry by a team of researchers from the University of Nevada, Las Vegas (UNLV) reveals that water can adopt lower-symmetry atomic structures under immense pressure.

Dr. Ashkan Salamat, the lead researcher and director of UNLV's Nevada Extreme Conditions Lab, explains that water's behavior under pressure is far more complex than previously thought. Typically, compressing materials causes atoms to get closer together, resulting in higher-symmetry arrangements. However, water defies this norm and becomes more disordered as pressure increases, altering its chemistry in the process.

To test their hypothesis, Salamat's team subjected water to pressures equivalent to 35 million pounds per square inch (PSI) in the lab, conditions comparable to those found on Neptune or Uranus. These ice giants are primarily composed of molten, metallic-like water, ammonia, and methane. The lab's findings suggest that water can exist in unfamiliar structural forms under high pressure, potentially taking on very different appearances than on Earth.

The researchers used spectroscopy and X-ray measurements to study the structural changes in diamond-compressed water samples. These tests revealed that water compressed to approximately 240 gigapascals (GP) adopted a lower-symmetry atomic structure, contrary to the expectation that compression favors higher symmetry. The study's findings emphasize the importance of understanding water's behavior under extreme conditions, as this knowledge is crucial for deciphering the nature of our solar system and the observable universe.