[dumbfoundded]

It's not a practical possibility. The black hole wouldn't last long and would be too small to actually absorb anything. It's the equivalent of asking if a nuke would set the atmosphere on fire.

Even a "large"ish primordial black hole would probably just pass straight through the Earth without anyone noticing.

Strange matter on the other hand...

[EA-3167]

Remember that Strange matter is only dangerous assuming a specific range of values for its surface tension, otherwise it's harmless and doesn't catalyze the conversion of normal matter into Strange matter.

[ls612]

What even is the smallest primordial black hole possible to still exist here 14B years later?

[dumbfoundded]

I'm not sure. Somewhere around 10^12 kg of initial mass would be evaporating today (1). So perhaps there is no meaningful minimum, only a minimum initial mass. If it's just about to evaporate, it could perhaps be arbitrarily small. Earth is ~10^25 for reference.

(1) https://en.wikipedia.org/wiki/Micro_black_hole#Expected_obse...