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starship-design: Blackhole, Railgun and superconductor
Timothy van der Linden writes:
> >Actually, black holes produce _more_ energy the smaller they are.
> >In fact, if you don't keep feeding it, it will explosively evaporate
> >away. Playing around with small black holes makes letting Calvin
> >play with a flame thrower indoors look positively safe.
>
> Are you sure about black holes producing more energy the smaller they are?
> I've heard that they evaporate faster and faster, but that's only because
> the surface:volume ratio gets bigger. I'd guess the total evaporated energy
> gets less if the surface gets less.
> But indeed if you would have 1000 small holes instead of 1 big with the same
> total mass, you'd probably be better of with the 1000 small holes.
I believe Isaac is right about this. Very small black holes evaporate
rapidly, to the point of being violently explosive. The evaporation
rate is a function of the gravity gradient at the event horizon, which
goes asymptotic as the mass of the hole approaches zero. Imagine the
energy release from a few hundred tons of mass turning into a spray of
high-energy subatomic particles within a tiny fraction of a second.