Uranus and Neptune
The idea of something being simultaneously a liquid and a solid should be rightfully confusing, because it seems to go against our basic understanding of how things like matter work. But ice (or water?) with those qualities may be pretty common in our outer solar system.

In a study published in Nature Physics, a strange substance known as "superionic ice" is described as such - not quite water, not quite ice, as conductive as metal, and almost molten in its texture, according to Raymond Jeanloz, a co-author of the study and professor at University of California, Berkeley.

While its existence had been suspected for some time, it was finally created and observed at the Lawrence Livermore National Lab.

First experimental evidence for #superionic ice: After decades of experiments, researchers have observed that under high temperatures and extreme pressures, water takes on a novel form and becomes superionic.

As you can guess, the process of creating superionic ice is not a simple procedure. Scientists first had to squeeze water between two pieces of diamond with a pressure of 360,000 pounds per square inch, creating a superdense form of ice that's 60% more dense than water and completely solid at room temperature.

But that's called "ice VII," and it's not superionic yet - the scientists then took this ice and blasted it with extremely hot lasers. And voila, superionic ice was born.

The reason why we've long suspected that this form of water ice exists is because its properties would explain some strange phenomena about outer planets like Uranus and Neptune. Being ice giants, if the two planets did carry large amounts of superionic ice within their mantles, it might explain why they have such unusual magnetic fields.

And based on what we know about those planets, they could very easily be undergoing the complicated process of making superionic ice underneath their surfaces. Jeanloz continues in a press statement:
"Magnetic fields provide crucial information about the interiors and evolution of planets, so it is gratifying that our experiments can test - and in fact, support - the thin-dynamo idea that had been proposed for explaining the truly strange magnetic fields of Uranus and Neptune. It's also mind-boggling that frozen water ice is present at thousands of degrees inside these planets, but that's what the experiments show."
NASA is gradually making plans to further explore Uranus and Neptune, including sending out probes designed to land on their surfaces.

And once these probes first make contact, it's going to be really important that we have some idea of what's going on underneath those surfaces.