Uranus and Neptune, the outer planets of our solar system, are water-rich gas giants. These planets have extreme pressures of up to 2 million times that of Earth’s atmosphere. They also have hot interiors, like the surface of the sun. Under these conditions, water exhibits exotic, high-density ice phases.

Researchers recently observed one of these phases, called Ice XIX, for the first time using powerful lasers to recreate the extreme conditions required. They measured the structure of Ice XIX with the Matter in Extreme Conditions instrument at the Linac Coherent Light Source, a pioneering X-ray laser facility, and showed that oxygen atoms are packed into a body-centered cubic structure, while hydrogen atoms move freely like liquids. significantly increases conductivity. His articles have been published in Scientific Reports.

NASA’s solar system exploration spacecraft Voyager II, launched in 1977, measured highly unusual magnetic fields around Uranus and Neptune. Scientists have considered exotic states called superionic ice as a possible explanation due to the increased electrical conductivity of these states. This study shows the existence of a previously undiscovered Ice XIX phase. This shows that this phase can form at the right depths and will help explain Voyager II’s magnetic data.

Water, a compound that is ubiquitous in our solar system and essential for life, exhibits an extremely complex pressure-temperature phase diagram, with 18 crystalline ice phases already identified. Nowhere are dense ice phases more important than in the interiors of gas giants such as Uranus and Neptune. Scientists hypothesize that the complex magnetic fields of these planets are created by exotic high-pressure water ice with superionic properties. However, it is known that the structure of ice is difficult to measure in such extreme conditions.

Using the Linac Coherent Light Source for Matter at Extreme Conditions instrument, an Ultrafast They found the first direct evidence of the stage.

At 200 GPa (2 million atmospheres) and 5000 K (8500°F), this new high-pressure ice phase, called Ice XIX, has a body-centered cubic (BCC) lattice structure. While other structures are thought to be stable under these conditions, the BCC Ice XIX structure would allow increased electrical conductivity much deeper inside ice giants than previously thought.

The results provide an important and intriguing origin for the multipolar magnetic fields measured for Uranus and Neptune by the Voyager II spacecraft.