Note: To begin with, I’ll say that I know our information on black holes is sorely limited… but there are a few things I’m wondering…
Most science articles I’ve read have described a black hole’s physical size (when size is mentioned) as only being a few miles across. Then again, others define black holes as being singularities (single geometric points). Which is it?
Does the former definition refer instead to the event horizon, and not the “size” of the hole itself? In other words, if you were to freeze the universe for a moment and nullify gravity, would you find a big blob of mass where a black hole is, or would you find a near-infinitely dense chunk of mass too small to be seen?
Further, what’s the largest a black hole can get? Take the theoretical black hole at the center of the Milky Way (how much evidence is there for its existence, anyway?)… how big would that black hole (or, rather, its event horizon) be?
(The reason I ask is because I’ve been thinking of a sci-fi story that details a ship’s travel - via reality-altering FTL drive - through the edge of a black hole’s event horizon. Yes, I know it’s impossible… but so is hyperdrive and phasers. :))