So, as CERN gets kicking along with its next accelerator in 2007ish, we can probably expect them to create microsingularities–mini black holes.
What uses are there for these, if they do not rapidly evaporate?
How strong would their gravity/time dilation effects be? Could we use them for artificial gravity (black holes under the floorboards of a spacecraft … or as a lift-assist on construction equipment)? Could we park them close to foodstuffs and archival materials to slow down decay (the “null-entropy” bins of Herbet’s Dune series)? Would they be a more efficient x-ray/gamma-ray source (by dumping matter into them)? Could this be a practical energy source?
Or are their effects too limited, and their lifespan too short for them to be practical?
A black hole need not be heavy at all: it is merely extremely dense, such that local spacetime is infinitely curved (ie. a singularity is the only future) and the escape velocity is greater then the speed of light. A black hole with a mass of an atom has a gravitational effect on the rest of the universe of just another atom. It would also stay as a black hole for only a brief period before evaporating due to Hawking radiation.
Micro black holes therefore don’t appear to have much practical use, save for advancing our understanding of quantum gravity and the benefits derivable therefrom decades or centuries down the line.
IIRC, on Star Trek-The Next Generation the Romulans used a microsingularity at the core of their warp drives. Seemed problematic in the event of a core breach but if you wanted to warp spacetime it would work and would probably be easier than throwing energy at the problem, like in the Federation drives.
Is the use of the word “probably” appropriate here? We should note that if the LHC can create mini black holes, cosmic rays, which pack many orders of magnitude more energy than the LHC can impart on a hadron, can create MBHs prodigiously when they slam into particles in the atomosphere. From what I understand, the decay of these MBHs ought to produce a characteristic and detectable shower of particles, but no such events have been conclusively observed.
If I recall, this idea of MBH creation at LHC may hinge on certain, as-yet-unproven quantum gravity models. Why theorists do not feel contrained by the lack of evidence for MBHs in the cosmic ray data I don’t know. Perhaps our physicist friends can explain.
You could, but would you want to? Once you feed a microsingularity enough that it’s stable, you’ll have to be very careful as it’s a one-way ticket into there. And the larger it becomes, the larger the containment device will have to be: you’ll need to somehow isolate it in a vacuum to prevent it from swallowing up everything (and we don’t currently know how to do that.)
If, as others have said here, we find a way to control it, once it gets past a certain size the best way to get rid of it would not be to contain it but rather cast it into outer space, but then we’d run the risk of creating an actual black hole in our solar system if the release wasn’t aimed right.
I’m not sure at what point microsingularities become stable enough that long-term storage is a problem, but one use for them could be disposal of high-level nuclear waste: radioactive particles go in, radiation comes out, but in a more manageable fashion and quicker.
Another problem: am I incorrect in thinking that once a microsingularity got past a certain size, to the point where you didnt need to feed it all the time to keep it from disappearing, that if it should break free from its containment it could basically mean the end of the solar system as we know it? That is, it could sink to the center of the world and create a black hole in the center of the earth, swallowing the earth of in a matter of weeks to decades, then starting on the rest of the solar system?
Well all you would have then would be a black hole with the mass of the Earth orbiting the Sun. Same situation as we have now just more compact.
Besides, all black holes evaporate eventually, I’d be curious to know what the breakeven point would be. You could feed waste in, use the radiation to heat the container to power some heat engine; the trick would be balancing the mass inflow.
You could feed it only, say, some positrons, and it would then be containable in an electric field, or even in a crystal lattice of some sort, if the charge were sufficiently small. I guess, since angular momentum is always conserved, the MBH would have some net spin as well, if you were careful about what you fed it, meaning if it were also charged, a magnetic field could contain it.
My very limited understanding of such things leaves me to belive that light, and thus photons, can’t escape black holes (hence the blackness). Since photons transmit the electromagnetic force, I would imagine that even if the matter inside the singularity was charged it would’nt effect outside charges and I couldn’t suspend it in a field.
Also isn’t there some rule that you can’t tell anything about what’s in a blackhole. If I could suspend it using electromagnitism, wouldn’t I then be able to see how much charge/spin the inside of my miniblack hole had.
Black holes have (so far as I know) three characteristics you can measure: Mass, charge, and spin (lest BHs violate associated conservation laws). You are right that real photons cannot escape a BH; but virtual photons (which mediate the EM force, not real photons) can, and do, since they’re not confined to light cones. Hence, you can feel the charge of a black hole. When you think about it, if gravity is mediated by the exchange of virtual gravitons (per any theory of quantum gravity), the BH must exchange virtual gravitons in an analagous way. I guess a more “classical” way to think about it is that gravitational fields and electric fields that are static simply exist no matter what the source of the field is doing. If you move the charge, sure, you get an EM wave that propagates at c, and that disturbance cannot escape a BH. But the static field extends always and forever from the charge off to infinity; and even if you put the charge behind an event horizon, this field isn’t suddenly cut off at that membrane. You can’t “feel” what the charges or masses are doing behind the horizon, but you know they’re there, just like you know the orignial mass that collapsed into the BH is there. Things could be playing hopscotch behind the horizon for all we can detect; that much we can never see. But the fact that they existed at all cannot be erased, so one can say the static fields that emanate from particles leave an “imprint” on the cosmos that is indelible.
As for whatever exactly is in the black hole, and can you recover information about it: This is a contentious question in the field of quantum gravity that hasn’t been resolved yet. Vritual particles do not carry “information” in the relevant sense, so they’re not a problem. Depending on who you ask, BHs destroy information permanently, or you can recover that information from the Hawking Radiation they emit. That’s about the limit of my understanding of the subject.