Everyone knows the three basic states of matter: solid, liquid, and gas. Most are probably aware that plasma is a word that means something. Yet there are other, more exotic states of matter that exist in extreme circumstances. Scientists at the University of Edinburgh have recently confirmed the existence of a bizarre new state of matter that is both a liquid and a solid. This discovery couldn't have been more perfectly timed than early April, lovingly referred to up here in New England as "mud season."
This new state of matter is far stranger than mud. Which isn't that high a bar, admittedly, but it's pretty strange. The liquid/solid hybrid state of matter was observed in potassium atoms under extreme pressure. When compressed to extremes, the potassium crystallized into a strange and surprising state—a "chain-melted" state— that managed to act as both a liquid and a solid. What does that mean? Described as a "leaky crystal," holding a chunk of this chain-melted potassium—although at the extreme pressures needed, your hand would be completely pulverized— would look like a solid block that slowly dripped molten potassium until it completely vanished.
One of the co-authors of the study, Andreas Herrman, a compressed matter physicist at the University of Edinburgh, illustrates it another way:
“It would be like holding a sponge filled with water that starts dripping out, except the sponge is also made of water.”
It is believed that potassium and other similar metals could exist in this state deep under the earth's mantle, where the pressure and temperature is extreme enough to do weird things to them.
This isn't the first time this state of matter had been observed, but until now scientists were divided on what they had observed. The first observation of this strange new state of matter happened 15 years ago, when scientists observed the phenomenon occurring in sodium atoms. Sodium crystals are normally extremely conductive to electricity and heat, but scientists discovered that when pushed to extreme conditions—20,000 times the pressure of the earth's surface—sodium transformed from a silver block to a transparent crystal that became resistant to electricity. Scientists didn't know what to make of it and weren't sure if this constituted a new state of matter or not.
The recent experiments with potassium confirmed it. After observing the chain-melted state in small groups of atoms, the team used artificial intelligence to simulate how groups of potassium atoms in the tens of thousands would behave. The simulations confirmed that what they were observing was the first example of a chain-melted element being thermodynamically stable.
Besides just being pretty cool, this discovery will help scientists model how elements behave at these high temperatures and pressures. Which, of course, doesn't have much of a bearing on me or you, but our comfy little oasis on planet earth is an anomaly in the universe. Most of the matter in the universe is contained in stars and planets and subject to the conditions that we don't have to deal with. So this discovery will allow scientists a much more detailed understanding of how those stars and planets—including our own—operate. And the rest of us? We get to deal with mud season.