Maybe it's a procedurally generated asteroid made out of solid-looking asteroid-gas

e: My actual guess is that they didn't bother with colliding with small objects when the spaceship is in "warp" mode or whatever they're calling it. It generates asteroids in front of the spaceship so you have to dodge them but when you're warping around a star system it's not going to bother with steering or trying to calculate collisions (when you could be moving over larger distances than a small object occupies every frame) or whatever.

At least, this is how I've seen it work on every other large scale spaceship game (mostly back in the early 2000s though)