Re: Not quite magic physics [was Re: Quantum Computers]

Eugene Leitl (
Sun, 22 Aug 1999 21:44:46 -0700 (PDT)

Speculations of manufacturing miniature black holes by focusing the output of e.g. Dyson sphere lasers on a small region of space have been discussed here before.

Iirc Sol is losing about 2 MT/s mass (though probably mostly to protons which go out as solar wind). This is not an extremely large amount if we consider how difficult it would be to focus it on a tiny region of space necessary for it to go singularity. Of course there are much brighter stars than Sol out there. (The ultimatively bright objects are massive black holes' accretion disks, the irony of using holes to make more holes...).

Also, the hole produces would be probably much to small and evaporate too rapidly before it can be stabilized by feeding it with matter.

Unfortunately, I think you will start generate particle pairs from vacuum way before, and this ruins your attempts to generate a critical photon flux. Any ideas at which critical flux the vacuum turns opaque (inverse problem to big bang universe going transparent) due to particle pair generation? You know I'm useless with physics.

What might work is very symmetrical implosion of spherical matter shell driven by above Dysonian laser; alternatively, one can consider imploding it with a pretty dense symmetrical antiproton barrage (has an advantage that you can release multiple star's output even at low conversion efficiences if you wait long enough to accumulate sufficient amounts of antimatter, of course this limits the rate at which you can churn out the microholes).

There are a number of interesting engineering issues associated with generating power from microsingularities, as to engineering the accretion disk both to attenuate the hard radiation sufficiently not to fry your collectors, and maintain your blackbody maximum in the optimal regime. I guess here a matter shell filled with attenuating gas could be useful. The inner surface of the shell could be used for photovoltaical processes or one could use the photons radiated by the outside of the hot shell. Alternatively, an orbiting gas/dust cloud could be used. Maybe multiple holes at the center, orbiting each other? They're small enough not to occlude other's radiation.

If all a microsingularity emits is really just blackbody EM they're obviously a very intesting power source (mass/energy conversion catalyst), if they can be cheaply manufactured. Otoh, they are pretty heavy (Mt..Gt) to be dragged around quickly using their own photonic output, would tend to catastrophic runaway in the high-flux regime (luckily, you need the more matter in the accretion disk the higher the flux/the bluer the blackbody (ouch! hard enough gamma will not be very well attenuated at all), but there is a delay in the autofeedback process).

I wonder whether gravitational microlensing data are compatible with the microsingularity/microdyson brains making up the galactic halo scenario. Intuitively, the critters would seem too small by far to be at all visible. (And they certainly aren't exactly bright in the IR, and their communication is indistinguishable from blackbody, oh woe).

I guess a lunatic physicist could write a sufficiently lunatic paper on this to ruin his academic career for good. writes:
> In the case of your photons, probably something similar happens.
> A simpler case would be two intersecting EM beams, such that the
> mass-energy in the intersecting region (E^2 + B^2 times a constant) is
> large enough to form a black hole. I don't think single beams can form
> black holes because the BH would have to be going at the speed of light,
> and I don't think this can happen. However with two crossing photon beams
> some components of the momentum cancel, and you are left with a black hole
> moving at less than the speed of light, of mass equal to the sum of the
> two mass-energies of the beams in the intersecting regions. I guess if
> your lasers were outputting continuous energy then you'd actually create
> a train of black holes heading outwards, but that is pretty speculative.