What are strange stars? You might be thinking, “Well duh, they’re stars that are strange”. And technically, you’d be right. Strange stars are indeed…strange. So post over, we can all go home, right? Wrong. There’s a wall of text below this paragraph for good reason. Strange stars are weird and fascinating and mysterious. So we’re going to explore why.
Just a heads up, the physics behind this stuff is pretty complicated, so we’re going to do a lot of simplification.
Strange Stars and Quark Stars
Strange stars can be lumped under the banner of quark stars, which in itself sounds like some weird physics jargon. Luckily, we have a post about quarks.
Quark stars, and by proxy strange stars, are really hot. Like no, they’re really, really hot. They’re also super dense, which is why they’re so hot. When things are dense and really compact, they heat up–think about the center of the Earth. It’s like 10,800 degrees Fahrenheit (6,000 Celsius).
Anyway, to get perspective into how stupid hot quark stars are, they’re so much so that atomic nuclei change to form a state of matter with free quarks. Basically, the heat and pressure are so high that the way matter behaves changes. The pressures and temperatures are so extreme anyway that they’re hard to observe.
Neutron stars are some weird little buggers, but unlike quark stars, we’ve observed these before. When a star dies it can undergo what we call a supernova. Basically a star blowing up. If a star is dense enough, it can become a black hole. A neutron star can also pop up if the star couldn’t become a black hole.
Once you get a neutron star, you’re looking at something so dense that it almost breaks the rules of physics. Bear in mind that neutron stars are the “normal” versions of quark stars. On the outside quark stars would probably look and behave a lot like neutron stars anyway.
But let’s put the density into perspective. We’re talking about something that’s so dense a spoonful of neutron star would weigh as much as like Mount Everest.
Here’s where quark shenanigans get weird. If quark star pressure gets even higher, you can get strange quarks. They can, in theory, create a “perfect” form of matter, known as strange matter. It would be perfect in density, and perfectly stable, but here’s the scary part.
It could be infectious.
If you know your thermodynamics, you know that everything in the universe tends to its most stable form. This makes perfect sense, everything is lazy. Anyway, if strange matter came into contact with not-strange-matter, it could turn it into strange matter. Imagine being touched by a subatomic particle and then Earth becomes a super dense ball of strange matter the size of a small asteroid. Bye-bye humans.
Luckily for us, strange stars (we finally got there!) probably aren’t prone to that. Strange stars, like quark stars, would look a lot like those super dense neutron stars we mentioned earlier. The difference is what’s inside. A neutron star has atomic nuclei that have basically fused together. Quark stars have weird quarks in them, and strange stars have those weird strange quarks in them. You’re only going to get a strange star when a neutron star has some exceptional mass–but not enough to become black hole.
Strange Matter Being Infectious
So we mentioned that this “strange matter” could be infectious. Which, when we think about it, is quite strange in and of itself.
Regardless, strange matter would only exist in a strange star–that’s because the center of a strange star is so compact it allows quarks to just be… free. That’s why it would theoretically be so stable.
Here’s where things could get bad for us, because neutron stars can collide. When they do that, they spew their insides out into space.
So if a strange star were to be involved in one of these collisions, it could spew out strange matter into the reaches of space. These (potentially subatomic) bits of strange matter are called “strangelets.” Because they’re so stable, they theoretically wouldn’t decay, flying through space until they collided with something. Then, they’d turn the thing they touched into strange matter ala the scenario we presented before.
Thankfully, that clearly hasn’t happened yet. Given that the Earth is like 4.5 billion years old and the Sun is pushing 4.6 billion years old, we can say we’ve made it a fair way without being hit in the face by a rogue strangelet. So it’s probably not gonna be happening anytime soon.
Enjoy looking up to the stars? See if you can’t see constellations here.