In the cores of neutron stars we might find the most dangerous substance in existence: strange matter — an element so bizarre that it completely bends the rules of the Universe and destroys everything it touches.
To understand how anomalous strange matter really is, we first need to understand a few basics:
- Neutron Stars: When a massive star explodes in a supernova, its core collapses under its own gravity with such an extreme inward force that it violently squeezes nuclei and particles together. Electrons are pushed into protons, creating neutrons, which then desperately try to push back against the gravitational collapse. If gravity wins, the star turns into a black hole, but if the neutrons win, the star turns into a neutron star, city-sized stellar objects that hold the mass of our Sun. Their cores are so dense that they change the rules of nuclear physics (we’ll get back to this later).
- Quarks: Protons and neutrons, the particles that make up the nuclei of atoms, are actually made up of even smaller particles called quarks. These fundamental components can only exist together as the building blocks of other particles and have therefore never been observed by themselves. Quarks come in various types, but only the “up quark” and “down quark” appear to make stable matter (protons and neutrons). All other quarks (charm quarks, top quarks, bottom quarks, and strange quarks) quickly decay into their most stable forms. However, this might be different when it comes to neutron stars.
One hypothesis states that, inside a neutron star core, protons and neutrons deconfine, meaning all of the atoms dissolve into a “bath” of quarks, resulting in a quark star (though from the outside it might not look any different from a regular neutron star). If the pressure is strong enough inside of its core, the star may literally get stranger. Essentially, some of the quarks in the core may be turned into strange quarks, which have bizarre nuclear properties. They are heavier, stronger, and if they pop up, they could create strange matter, the ideal state of matter — perfectly dense, perfectly stable, and indestructible. In fact, it’s so stable that it might be able to exist outside of neutron stars, and that’s a problem. It’s possible that every piece of matter that it touches will immediately turn into strange matter too. We would immediately cease to exist if we were to be touched. The only way to get rid of it would be to throw it into a black hole, which of course, we have no means of accomplishing.
But, should we care? After all, strange quarks are inside of neutron stars… except when neutron stars collide with other neutron stars. When this happens, they vomit enormous amounts of their insides, some of which could include strangelets, little droplets of strange matter. These strangelets would drift throughout the universe for millions or billions of years until they collide against a star or planet by chance. If they were to strike Earth, the whole planet would immediately be converted into strange matter. If they were to hit our Sun, it would turn into a strange star, incredibly reducing its size, so much that its warmth wouldn’t be able to reach Earth.
In the end however, all of this is hypothetical. If the Earth and Sun and other nearby planets haven’t been consumed by strange matter over the past few billion years, then it probably means that it won’t happen in the near future.