While sitting in our middle school science classes, we are taught the basics of the natural world around us – gravity, photosynthesis, weather, and of course, the states of matter.
As almost anyone who has gone through the public school system in the last century will state – there are three fundamental states of matter: solid, liquid, and gas.
When we look at the world around us, those three states can define almost every single thing we see, from the smell of the gas stove and the coffee we drink to monsoons and mountains. However, your science teachers weren’t telling you the whole truth… not even close.
The Two “Other” Common States of Matter
While there are indeed three dominant states of matter, there are other far less common states that don’t get the attention they rightfully deserve. Let’s take water, for example, with its three well-known states: Ice (solid), Water (liquid) and Vapor (gas).
The fluctuation of states between any solid, liquid, and gas is dependent on temperature and pressure. When you increase the temperature of water, it evaporates into vapor. When you lower the temperature or increase the pressure on water vapor, it will condense back into water. When you raise the temperature of ice, it becomes a liquid. We understand those basic principles, but what happens at the extremes?
These three fundamental states of matter occur within normal ranges of pressure and temperature, but when you heat a gas to extreme temperatures (like those found in the sun or around a lightning strike), a new state of matter is achieved: plasma. When you heat gas to a certain level, you can excite the electrons enough to separate from their nucleus and begin interacting with any other nuclei that are in the vicinity. Gas inside neon signs is a popular example of plasma.
At the other extreme, when you lower the temperature of a substance far enough (near to 0 Kelvin, also known as absolute zero) the bosons of that substance all fall into the same quantum state, so that they resemble a single wave or particle. This is known as a Bose-Einstein condensate.
Now we’re up to five, and we’ve barely scratched the surface. Plasma occurs naturally in the world around us, while Bose-Einstein condensates require carefully manipulated laboratory conditions, but that doesn’t mean they should be ignored!
The Stranger States of Matter
In the past century or so, atomic physics, particle accelerators, quantum theory, and ever-improving technology have revealed many other modern low-energy states of matter. We have found superfluids and supersolids, which are cryogenic liquids and certain solids that are able to flow or move without friction at extremely low temperatures. We have also identified “degenerate matter”, typically found in the center of stars, where protons and electrons bind into neutron cores, or where electrons can be shared between different atoms.
At extremely high pressures, certain substances lose all distinction between a liquid and a gas, earning it the name “supercritical” liquid. In a “Jahn-Teller” metal, a solid substance has all the basic qualities of an insulator, but acts as a conductor due to a unique crystalline shape of the solid atoms.
When discussing high-energy states of matter, the most talked about form is Quark-gluon plasma, which is the state of matter that supposedly existed in the instants after the Big Bang, when the four fundamental forces of the universe were actually joined into one force, before temperature and pressure decreased and allowed them to separate. Quark-gluon plasma (QGP) is theorized to have behaved as a gas, but in recent particle accelerator experiments, something very similar to QGP was created that instead behaved like a “perfect liquid”, meaning that the substance moved in a concerted pattern, almost like a flock of birds.
Just in the past month, researchers have finally been able to create the conditions to explore a theory made nearly a century ago. It is thought that the core of our solar system’s largest bodies (the Sun and Jupiter) is composed of a unique form of hydrogen that can only be present at extremely high pressures. This “metallic” form of hydrogen has never been observed, because it would require pressure nearly 3 million times greater than our atmospheric pressure on Earth.
However, scientists finally managed to approach those high-pressure conditions by squeezing hydrogen molecules between diamonds. They were thrilled to observe partial atomic and metallic states of hydrogen, where molecules began breaking down into constituent atoms, and electrons began behaving as they would in a metal.
These types of advancements and experiments aren’t likely to slow down anytime soon, because the technology and skill to manipulate the physical aspects of our universe are becoming more attainable. Theories are finally manifesting into findings, which drives research even further into strange combinations of conditions.
While a detailed explanation of every new state of matter is beyond the scope of this article, suffice to say that currently (and this could change at any time), there are 4 classical states of matter (solid, liquid, gas, and plasma that are naturally occurring), and a dozen non-classical states that require artificial conditions to be observed.
From the most insignificant quantum scale to the massive cores of interstellar gas giants, the many states of matter are diverse, bizarre, and fascinating aspects of the natural world that may just help us understand Life, the Universe, and Everything.