the sun in any given solar system, well, exists as a giant glowing ball, like you would expect. however, there is nothing that stops you from flying straight into it. you can just plunge your ship into a giant stellar furnace and it's fine.
which is weird, since thermal and electromagnetic damage are two of the four damage types in the game. if someone shoots you with a laser, you take thermal and EM damage. but the sun is fine. ok.
once you get past the surface of the sun, it just disappears entirely. there's a few weird lighting effects, but the bright glow is gone. then, tens of thousands of kilometers away, there's a single spot all the lighting effects are coming from. the game flags that as the sun. the singularity at the center of the sun is the actual sun, i guess.
as soon as you touch this, the game's physics engine freaks the fuck out. physics in that game care about an object's mass and speed, so a small ship slowly bumping into a big ship will only bounce off, while a big ship at ramming speeds will easily knock you off course (and is a legitimate strategy to stop people from warping away from you). there are also some ship modules that will increase your ship's mass to ludicrous levels, so even your own thrusters can't do anything, let alone people ramming you - effectively rooting you in place for a period, forcing you to really commit to the fight if you want to activate your doomsday cannon or whatever.
so what happens if you touch the center of the sun, which contains all of a star's mass inside a single, infinitely small speck, while also activating a module that makes your ship's mass infinitely high?
your ship gets stuck like this for several minutes until you can finally slow down enough. which i mean. in a game where every single ship is capable of faster-than-light travel, maybe that's not actually that impressive. but it's a very funny solution to "two objects with infinite mass are inside each other".