Humanity is getting through a very strange time. It’s as if the last season of Game of Thrones wasn’t enough, now humanity faces a global pandemic that, of course, this is why today’s topic will be just as strange as the timeline that we live in - strange matter – possibly the most stable thing in the entire universe. Actually, strange matter’s full name is strange quark matter, which means a state of aggregation involving quarks moving freely in a system. There also are the gluons, which act as the exchange particles for the strong force between quarks, but they’re irrelevant for now.
Normally, quarks are held together by this strong force and subsequently form subatomic composites like protons and neutrons, just like how the electromagnetic force holds together atoms to make molecules. However, if we rise the temperature higher than 10^12 kelvins, those subatomic composites melt into the components they are made of, creating a hot soup of quarks. This soup was first served in the very early universe when it’s age was only a few tens of microseconds and the temperature was high enough.
But other than that, theoretically, this quark matter can also form in the interior of a neutron star. Briefly, as a refresher, a neutron star is what appears after a giant star with a total mass of between 19 and 29 solar masses collapses after running out of fusion fuel. Because of its such immense mass, it compresses to a density big enough to fuse the electrons and the protons inside the atoms into neutrons. Hence its composition being just… neutrons. Firmly packed together and held by the gravitational force, they create the substance known as neutronium – the hypothetical element of atomic number zero.
And what’s the best way to demonstrate the density of such a substance?
Measuring a cubic centimeter?
No.
A tablespoon?
Nope.
A cow – yeah that’s it. If a cubic centimetre of neutronium weights at least 370 mln tons, then a cow made entirely from neutronium would weight 370 Quadrillion kg. Even though the star is much cooler than 10^12 kelvin, because of the high pressure, the core of the neutron star is extreme enough to form quark matter inside.
Considering that a proton is made of 2 up quarks and one down quark, after fusing with an electron, it becomes a neutron consisting of one up and 2 down quarks. Hoever, if we make the current situation even more extreme by rising the temperature and making the density of the star even higher, things get weirder. The weak force, the one responsible for quarks changing their types, starts to manifest itself
in such an environment and transform half of the down quarks into the brand new… awesome… strange quarks.
The resulting plasma made of aproximativelly equal parts of up, down and strange quarks is what scientists call strange matter and the star that it forms – a strange star. You may think about strange matter as that one weird kid in class that gets bullied into him breaking inside under social pressure and thus letting him no other choice but to accustom the quark-social standards and become like everyone else. But actually no. Strange matter is a true chad, stable enough to resist the influence of others, and actually becomes the social standard for everything it comes in contact with.
In other words, strange matter is believed to be stable enough not to decay into other particles, no matter the conditions, and convert the matter it comes in contact with in even more strange matter, but we will come to that later. First of all- its stability. As previously mentioned, the initial quark matter is made of up and down quarks. When we rise the density, the weak force will start to lower the energy of the entire system by transforming some down quarks into strange quarks, which have a smaller mass and permit a lower energy level.
There are also other canditates for this transformation beyond the strange quark- the three remaining quarks – top, up and charm. But their masses are much larger than the chemical potentials involved.
Also, the transformation reactions are a bit more complicated than simple down to strange conversion, but let’s keep things simple. So, again, the presence of strange quarks in the strange matter make it the most stable substance in the entire universe. A perfect and indistructable material for the SkyNet army. But in reality, not so perfect. Remember when I said that strange matter will convert other matter it comes in contact with into even more strange matter?
You would be tempted to think about it like an infection, but the process is more analogous to actual burning. That said, you need enough strange matter to maintain it stable and start a reaction. If you have too little of it, it will simply decay back.If we however get more than the threshold of required strange matter, we get an aglomeration
called a strangelet. And in simple terms, this strangelet can burn through matter in its vicinity lowering its energy level, and therefore transforming it in even more strange matter, thus continuing the chain reaction until there is no more matter left. So, do these seeds of doom exist?
Unfortunately or rather fortunately, there is no convincing evidence in favor of the existence of strangelets. If a strange star would exist with a mass bigger than 1.4 solar masses, it would be indistinguishable from a simple neutron star of the same mass. However, if it had a smaller mass, its radius would be respectively much smaller than the radius of a neutron star with similar mass. These differences of proportions would let us know if we ever stumble upon a strange star, and therefore – strangelets. Nevertheless, strangelests could have also formed in the first seconds after the Bing Bang - when the universe was nothing more than a quark soup, similar to the quark matter which supposedly exists inside neutron stars.
So there is a chance, even if not big, of strangelets still lurking through the darkness of the universe, waiting to land on some unlucky planet and burn it to the core, converting everythign to even more strange matter. Would be a shame if you happen to have been living on such a planet, wouldn’t it?
Sadly you can’t yet teleport to some other planet in order to save yourself. What can you do though, is teleport your online presence to anywhere thanks to our today’s.