@Thaminga @VoxSomniator I'm trying to figure out if this even makes sense and having some difficulty!

I should note perhaps that a black hole does not have to have any matter in it at all. Look up the term kugelblitz.

@Felthry @VoxSomniator it still has a mass, though
the fact that the constituent mass of it comes from light doesn't really change that, they're equivalent at the end of the day, it'd just have skipped the stage of ordinary matter along the way

@Thaminga @VoxSomniator I also think the transition from energy to matter is fundamentally different from the transition into a black hole. Maybe just that a black hole is fundamentally a point discontinuity in spacetime, whereas matter is not, to my understanding, a discontinuity in any field. Black holes also do not have an equivalent conservation law; there is no law that states that black holes must be created in pairs like how ordinary matter must be paired with antimatter

@VoxSomniator @Thaminga I should perhaps say that I'm just thinking through this and trying to see where the analogy works and where it doesn't. I'm not trying to say you're wrong or anything of the sort.

@Felthry @VoxSomniator of course! then again, we don't exactly have anti-energy either
sure, there's negative energy -density- but that's not where antimatter comes from
it's kinda like how in geometry you can have exactly one regular shape in one dimension (a line), an infinite number in two (regular convex and star polygons) but only ten in three dimensions (sphere, platonic solids, kepler-poinsot polyhedra)

@VoxSomniator @Felthry basically, what I'm getting at is that between each boundary the laws of physics apply in ways that aren't necessarily completely straightforward looking from the other's perspective

@Thaminga @VoxSomniator Yeah, that's a fair point.

I think a good analogy for the energy-matter transition might be a phase change. And in fact it might /be/ a phase change if you look into it enough, I'm not entirely sure

Another point, matter comes in defined, quantized units, while black holes do not. You can have a black hole with half the mass of another, but you can't have an up quark with half the mass of another. Same goes for other properties, like angular momentum.

@Felthry @VoxSomniator Sorta~ There's still the fact that adding energy to matter will increase its mass - similarly, adding either to a black hole will increase its mass. Between the phenomenon of Hawking radiation and the fact that adding energy to a black hole doesn't necessarily make it move like it would ordinary matter (it'd simply vanish behind the event horizon and contribute to its mass), of course we wouldn't see quantized values for black hole mass.

@Thaminga @VoxSomniator I should perhaps have been clear on referring to rest mass in the previous post! And adding energy to non-black-holes doesn't necessarily make them move either (potential energy is still energy)--it's adding the other conserved quantity, momentum, that does, same with black holes.

@Felthry @VoxSomniator Temperature still makes atoms move about though, even if it's just them vibrating in place. Black holes... have no such thing, not that we could ever hope to observe at least.

@Thaminga @VoxSomniator I'm not referring to temperature. Consider increasing a particle's gravitational potential energy by lifting it up.

@Felthry @VoxSomniator True, but you're already expending energy on it by lifting it up in the first place, and it's going to move as a result of that potential energy -eventually-.

@Thaminga @VoxSomniator The same can be said of black holes. Everything will eventually come out as hawking radiation.

@Felthry @VoxSomniator Mm, yes. It's more that you can't directly impart momentum on a black hole through energy, I suppose. Matter can take up and give energy at any quantity and at any time depending on how it interacts with other matter, black holes can consume it at any rate but are stuck radiating it back out at a given rate depending on mass - the lone exception being momentum imparted on it through gravity from objects made of (anti)matter.