That's terrifying. Imagine a rogue supermassive black hole floating in intergalactic space.
But I mostly want to know how badly self-interacting dark matter messes up the existing LCDM simulations that most astrophysicists sort of rely on?
Why terrifying? It's literally doing nothing, far away from anything. Seems like the safest place for it to be.
A supermassive blackhole floating towards you would have very visible effects, it would be impossible to miss for millenias before it gets to you.
It's the micro black holes which can hit you without a warning.
Micro black holes are only hypothesized so far, but they could get very small - e.g. a black hole with Earth mass would have less than 1 centimeter in diameter.
The size itself is not that important for spotting black holes, though. Even if it's as large as a star, all you see staring at the black hole "object" is nothing. What's important are the gravitational effects on the environment, and there the differences are stark. At a distance of 1000 light years, it will be difficult to spot a stellar-mass black hole floating through empty space, because its pull is strong enough only at stellar distances and won't produce enough disturbance in interstellar space for us to notice. OTOH supermassive blackholes will deform whole surrounding star systems because of its immense mass and gravitational pull. A micro black hole (e.g. Earth mass) passing through the solar systems would likely go undetected unless it collides with something (which is improbable). There could be a measurable disturbance, but it would be one-off and difficult to attribute to a black hole.
Solar wind? Would it generate some interesting effects when coming too close to a black hole? All these protons accelerated to a near light speed, probably hitting each other and running away into a black hole.
Damn straight! I dare to assume you ignorant jackasses know that space is empty. Once you fire this hunk of metal, it keeps going till it hits something. That can be a ship, or the planet behind that ship. It might go off into deep space and hit somebody else in ten thousand years. If you pull the trigger on this, you are ruining someone's day, somewhere and sometime. That is why you check your damn targets! That is why you wait for the computer to give you a damn firing solution! That is why, Serviceman Chung, we do not "eyeball it!" This is a weapon of mass destruction. You are not a cowboy shooting from the hip!I always imagined it as being caused by a rogue mini black hole zipping through.