From: Eugene Leitl (eugene.leitl@lrz.uni-muenchen.de)
Date: Sun Aug 22 1999 - 22:44:46 MDT
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.
hal@finney.org 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.
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