If you draw a box around the solar system, and want a fast moving BH to settle in without rejecting on hyperbolic orbit, you'd just have to throw out another ob

If you draw a box around the solar system, and want a fast moving BH to settle in without rejecting on hyperbolic orbit, you'd just have to throw out another object that's comparable in size, at comparable speed. Momentum conserved. A near miss with one of Jupiters moons might sling the BH into an orbit at slower pace and throw that moon into, say, earth to create our own moon. This stuff probably happens more often than we think, on a galactic time scale.