Quote Originally Posted by Schmaven View Post
If a black hole of low mass (a few thousand kg or something) was close enough to a planet, would it just suck in mass from the planet and become even more massive, and thus increase it's event horizon radius and increase it's range of devouring more mass and growing even more? That sounds too badass.
A few thousand kg black hole wouldn't be able to encounter matter in such high density that it would be able to stave off its own evaporation. Even if it was encased in solid critical mass uranium it probably wouldn't stand a chance of expanding. It might survive in the core of a star or large planet like Jupiter, maybe.

To really have a chance of a black hole expanding it needs to be several times the mass of our sun.