Investigating Artificial Black Holes

Robber Baron writes "I remember years ago watching a cartoon in which an inventor had managed to create 'portable holes.' Now along those lines, according to this story in the Christian Science Monitor, scientists are on the threshhold of developing the 'do-it-yourself black hole' (Well, no, it's not quite do-it yourself as you need a pretty large collider to pull it off.) They're hoping to use the new Large Hadron Collider at the European Center for Nuclear Research to create many tiny black holes and observe the Hawking Effect as they dissipate. Keep your shotgun handy though, as they are more than likely going to open up a portal into another dimension and all sorts of nasties are going to come pouring out."

Is this dangerous?

[Sanity]

I always thought that if a black hole existed on Earth there would be a risk that it would start to pull in the matter around it, exponentially increasing its own mass and eventually sucking in the entire planet.

I assume this won't happen, but can anyone explain why?

Boooooom

[frenztech]

So...

a) How long does it take one of these micro blackholes to decay. and...

b) Are they positive that a blackhole will just decay nicely. The big bang only took one particle supposedly, so...what happens when a blackhole pulls in upon itself? Boom?

Re:Is this dangerous?

[jericho4.0]

Top of my head, possibly wrong answer; Blackholes slowly evaporate over time, due to the Hawking Effect. As a hole loses mass, the effect goes faster. The amount of mass used in these experiments will result in a hole that evaporates in a tiny fraction of a second. In that short a span, there is not enough time to pull in enough mass to stop the evaporation.

I still would not like to know the exact time of this experiment :-).

Re:Is this dangerous?

[Billly Gates]

But lets say a miny blackhole was formed on the edge of the accelerator. With more mass it would not evaporate quickly enough. Eventually within seconds would suck up the earth itself. By now it will be too big to evaporate because of the increase in mass.

The hawking effect is only theory is in fact if your wrong we all perish. Sounds too risky for me.

Re:It was Wile E Coyote

[antiquark]

The thing that always stuck me about Wile E Coyote's plans is that occasionally he would have a brilliant plan, but something would go wrong, the rope would come loose, or the buckle would break.

Then he's move onto the next plan.

I'd be yelling at the TV, "Try it again! It's a good bloody plan!"

The other amusing thing about this is I keep seeing the same situation in real life. Someone would try one thing, it would go wrong, and they'd decide it was obviously a bad idea, whereas thats not necessarily the case.

Re:No, stop him!

[UrGeek]

Here is that paper from the RHIC (the Relativistic Heavy Ion Collider) at Brookhaven National Lab:

http://www.bnl.gov/rhic/docs/rhicreport.pdf

It it titled "Review of Speculative 'Disaster Scenarios' at RHIC".

However, they did shut it down for a bit to "upgrare some detectors". Probably true, but I did notice that instead of banging gold ions against gold, they are banging gold against deuteron. Makes you go "Mmmmmmm". I, for one, am glad that someone is thinking about this and perhaps weighing on the side of caution.

I still would feel better it was done beyond the orbit of Mars or further!

Why are electrons not black holes

[mdubinko]

Something I've wondered about: Electrons definately have mass, and seem to have a zero physical size.

So, why are they not black hole singularities with infinite mass? Why don't they evaporate in a puff of Hawking radiation?

They should read some sci-fi first...

[TexVex]

James P. Hogan [jamesphogan.com] has written about artificial black holes in at least two of his novels. In Thrice Upon a Time [jamesphogan.com], scientists accidentally created a bunch of microscopic black holes tha turned out to be stable, and proceeded to destroy the earth, pac-man style. In The Genesis Machine [jamesphogan.com] a machine can create small singularities and turns out to be useful as a doomsday weapon.

Ok, so it's just sci-fi and the author ignores (or misunderstands) relativity, causality, and quantum mechanics. And it's still a good read. But -- if these guys are actually going to go creating singularities, could we make 'em set up shop on the moon to do it? I'd rather not have a black hole in my back yard. Yes, I know the article makes some reassuring statements about the incredible smallness and short life-span of such a thing. But, seriously, splitting the atom led to the Cold War and we're all still sitting on enough nukes to turn Earth into a warm glob of glowing goo. I hope we don't rush headlong into this singularity thing -- what if it turns out to be more dangerous than fusion bombs?

Re:What if

[Anonymous Coward]

until it collides with another electron, of course, and eats that electron. then it has the mass of three electrons, etc, etc.

Eddington limit

[dark-br]

Just speculating, but since black holes do evaporate, and the smaller they are the faster they evaporate, I wonder what the implications of evaporation would be in the presense of an acretion disk.

Given that in the process of evaporation, a black hole emits radiation, at some point the radiation pressure from the evaporation would balance out the force of gravity pulling matter into the black hole so then the black hole might stabilize in size.

Surely they'll have named that limit already, but I don't think it's the same as the eddington limit.

Or perhaps there won't be a limit here because the cross section area of the acretion disk would be so small compared to the surface area of the event horizon. (yes, I think that incoming matter would have to form a disk and not form an acretion shell)

Re:Is this dangerous?

[Dylan Zimmerman]

If I understand correctly, they plan to make some of those proton-sized toroidal black holes. They should only exist for a few billionths of a second before their gravity is no longer enough to maintain a Schwarzschild Radius and they simply become very massive subatomic particles.

The temporal shear should only extend a few angstroms from the SR, so we don't really have to worry about it tearing stuff to pieces. Its gravity should only be a few nanometers per second squared any more than a few meters away from its surface, and that's barely detectable, so no worries there.

We could actually learn quite a bit about space-time by observing these black holes.

I have always wondered what happens beneath the Schwarzschild Radius. Since time dilation approaches infinity as you approach the Radius, wouldn't time be at a standstill inside the black hole? Therefore, material would accumulate at the surface and never move any further in because time stops for anything inside. You would get an infinitely thin layer of very high density right at the SR. Of course, since the more matter a black hole consumes, the more massive it becomes, the further its SR is from its center, so you wouldn't ever get a shell, you would find something more like a fog.

If anyone knows that any of the above is wrong, then please reply and correct me. It just seems to be what would happen based on what I know of physics and relativity.

Oh my.

[NegativeK]

I fear that this post may be lost in the numbers surrounding it, but it needs to be said. First off, I'd like to give an example of how utterly tiny this thing will be. If the sun were to turn into a black hole instantly, its event horizon would have a 3km radius. For the sun, that's extraordinarily tiny. According to the article, this thing should have the mass of a couple hundred protons. That's, in case you can comprehend these numbers, 1.67*10^-25. Now, the radius of this bugger will be that times 1.48*10^-27. Yeah. That's FREAKING TINY. 2.47*10^-52 tiny. Many many many orders of magnitude less than the Planck distance.

Now, to address another issue. Hawking radiation is a pretty solidly entrenched idea. Particle and anti-particle pairs do form in space - the existance of the particles which are a part of it have been experimentally verified through the Casimir effect, which is Googleable. So worries about that not happening are pretty unnecessary. And, as many others have stated, these microscopic black holes have been forming and evaporating all the times due to cosmic rays right above our heads.

For those who wish to learn more about black hole physics, I have to suggest an excellent source for the layman: Jillian's Guide to Black Holes. [dragonweave.com] She can explain things in simple terms, and has some hefty gravitational wave and Penrose diagrams for the really interested.

Oh, and P.S.: If the world really is sucked up by a black hole, it'll be a saving grace for all of the physicists who have been extraordinarily wrong for the past three-quarters of a century. ^-^

And yet another P.S.: For those physicists out there, what interesting things start to happen with black holes at scales this much past the Planck length? I believe that I've read somewhere about quantum gravity showing up heavily, but I'm unsure. =)

Re:Is this dangerous?

[Anonymous Coward]

Real matter that's falling inside of the black hole doesn't tunnel out, but you can think of Hawking radiation as a vacuum tunneling process [arxiv.org]. This is a quantum effect; it doesn't have to do with classical acceleration radiation (electromagnetic / gravitational waves).

Re:Oh my.

[Anonymous Coward]

We have very little idea about what happens with sub-Planckian black holes, actually. Our current theories of quantum gravity have trouble with even Planckian holes.

Re:In all seriousness

[PSC]

Natural cosmic ray (probably created by supernovae or hypernovae) are far more energetic than any puny little collision we can muster.

First off, the origin of 10^20 eV cosmics is not at all understood. The Auger experiment [auger.org] for example is investigating this question.

Second, those very high energetic cosmic particles crash into earth (or whatever object in their path), which is basically at rest (compared to the speed of the cosmics). In particle physics, this is called "fixed target mode". Since both energy and momentum are conserved in the crash, the particles produced in the collision are not at rest but must carry the momentum of the cosmics (think billard). Thus, only a small part of the energy of the cosmics is avalable for forming new objects, namely sqrt(E), which is only 10 GeV, well within range of terrestral accelerators since over 10 years. The rest of the cosmics' energy just propels the new objects.

The Large Hadron Collider at CERN will crash protons at 7 TeV energy against other protons of the same energy/speed but opposite direction. This is called "collider mode", and the entire energy of 2x7=14 TeV is available for new objects.

(Well, not really, since protons are themselves compound objects, made of 3 quarks and lots of "gluons" which glue the quarks together. So really its only a quark-quark or gluon-gluon collision with less than a sixth of 14 TeV but still more than the 10 GeV above.)

There is of course the possibility of a cosmic particle colliding with another cosmic particle, but given the rate of 5 of those cosmics per 1000 km^2 per year, and the very low cross section of these high energetic particles, this isn't going to happen very often :-)

James P. Hogan, Inherit the Stars

[Anonymous Coward]

There is a series of Sci Fi books that I particularly like by James P. Hogan. In those books, the (friendly) aliens use artificial black holes. One use is, they create a microscopic black hole and use its wormhole effect to send radio signals light years instantly. There was a spy on Earth and the main character sniffed him out by noticing that his house was built out of material necessary to support a massive weight, way out of proportion to the actual house. Of course! It was the weight of the microscopic black hole used to transmit data back to his headquarters, light years away.

Re:Is this dangerous?

[Anonymous Coward]

There is no intention to "stabilize" a black hole, for the simple reason that the LHC isn't a black hole factory.

The fact is that there are some _extremely_ speculative theories which attempt to explain the weakness of gravity by invoking "large" (up to mm scale) extra dimensions in which only gravity propagates. One side-effect of these theories is that gravity becomes comparable in strength to the other forces at much lower energies than in conventional theories - low enough that you could produce mini black holes at the LHC. If you can, then they will decay spectacularly in a picosecond or less (i.e. still inside the vacuum pipe of the accelerator).

But remember, these are highly speculative theories, requiring fairly contrived sets/sizes/properties of these extra dimensions to fit the existing data (you need 2 dimensions in which the universe is a bit less than a mm across, both of which propagate gravity but nothing else). I wouldn't bet heavily on them being true, and there is a reasonable chance that they will be disproved by more conventional gravity experiements before the LHC switches on.

For those of us working on the LHC, this idea is a piece of attention-getting fun, but definately a long shot, and not at all the reason we are building the thing.

As for safety, as someone has already said, cosmic ray interactions regularly contain more energy than this, so if this process could produce a stable black hole which would swallow the Earth we wouldn't be here to discuss it.