What are 'mini' black holes?

Mar 29, 2010 by Pete Wilton
Simulated production of a black hole in ATLAS. This track is an example of simulated data modelled for the ATLAS detector on the LHC. These tracks would be produced if a miniature black hole was created in the proton-proton collision. Such a small black hole would decay instantly to various particles via a process known as Hawking radiation.

In films and books black holes capture unwary spaceships and planets, gobble up whole galaxies or offer portals to other parts of the Universe.

So the idea that, with the start of the (LHC), physicists finally had a machine powerful enough to, potentially, create ‘mini’ black holes caused some alarm.

But what do we really know about black holes? And how would a ‘mini’ one be different from their giant cousins lurking out there in space?

‘The simplest black holes are objects with a singularity in the centre and that are surrounded by an ‘event horizon’,’ explains Cigdem Issever of Oxford University’s Department of Physics. ‘Once something comes closer to the black hole than the radius of the , it is not able to leave: even light can’t escape and so the name ‘black hole’ was given to these objects by John Archibald Wheeler back in 1967.’

A hole in the Sun

Producing black holes turns out to be about mass (energy): squeeze mass into a sphere with a radius equal to what’s known as the ‘Schwarzschild radius’ - a threshold beyond which gravity causes an object of a certain density to collapse in on itself - and a black hole will form.

‘In fact the size of the Schwarzschild radius is directly proportional to the amount of mass that is squeezed in, as well as being directly proportional to the strength of gravity,’ Cigdem tells me.

‘For example, in order to form a black hole out of our Earth, you would need to squeeze its mass into a sphere about the size of a marble (radius 8.9 mm). By comparison the Schwarzschild radius of the sun is about 3 km.’

So what would happen if we swapped our Sun for a black hole?

‘If we replaced our Sun with a black hole of the same mass, surprisingly, not much would change in our solar system. The planets’ orbits would stay the same because the that the black hole would produce would be exactly the same as that of the Sun. Although, admittedly, the would be a bit dark and cold!’

But Cigdem’s interest in black holes isn’t theoretical, as a particle physicist she will be searching for signatures of ‘mini’ black holes in the LHC collisions:

‘I became interested in them as a particle physicist back in 2003 because extra dimension models predicted that they may be produced in high-energetic cosmic rays and, if so, even in particle accelerators. If we are really able to produce them, they could give us experimental insights into quantum gravitational effects.’

She hopes that studying them may lead to a formulation of a theory of quantum gravity: marrying Einstein’s theory of general relativity (which describes gravity on large scales) with quantum mechanics (which describes physics at very small distances).

The LHC is colliding protons on protons. These protons are made up of smaller constituents, the so called ‘partons’ which are actually the particles the LHC is colliding. The Schwarzschild radius of two colliding partons - quarks and gluons for example - at the LHC is at least fifteen orders of magnitudes below the Planck length - the smallest distance or size an object can achieve in our conventional universe.

‘This means that, in conventional models of physics, there is no way a black hole could be produced in a collision of two partons. However, there are models on the market suggesting that the strength of gravity could become significantly larger at very small distances, up to 10 to the 38th [10 with 38 zeroes] times stronger,’ she comments.

‘If this is true then the Schwarzschild radius of two colliding partons becomes large enough that, at the LHC centre-of-mass energy, two partons passing each other at their Schwarzschild radius is not so unlikely anymore. So, we may be able to produce microscopic black holes after all.’

Who's afraid of a 'mini' black hole?

So what would these tiny black holes be like? Should we be worried about them?

Cigdem tells me: ‘According to Stephen Hawking, they will not be that black in fact. They will evaporate with time approximately following a black body radiation spectrum. The evaporation rate will be inversely proportional to the black hole mass.’

‘Astronomical black holes are so massive that their evaporation rate is negligible. In contrast, mini black holes are hot: unimaginably hot. The core of our Sun is at around 15,000,000 degrees Kelvin - to get close to the temperature of a mini black hole you would need to add another 42 zeroes.’

‘What this incredible temperature means is that mini of tiny mass ‘evaporate’ into the far, far colder space around them almost infinitely fast. Their expected lifetime is around one octillionth of a nanosecond - so that they pop out of existence again almost as soon as they are created.’

If they do appear they will almost instantaneously burst into many particles which the ATLAS detector should pick up.

‘These particles will have very striking features. The total energy deposited in the detector will be of the order of a few TeVs [Tera electron volts] and the number of final state particles will be large. Black hole signatures can hardly be imitated by any other new physics so, if they are being produced, it will be hard to miss them,’ Cigdem adds.

So the hunt begins: on 30 March the LHC is aiming for collision energies of 7 TeV that may enable us to see some quantum gravity effects for the first time.

At the beginning of this year Dr Cigdem Issever moved to CERN to coordinate the efforts of the ATLAS Exotics physics group.

Read more about this topic in What black holes can teach us by Sabine Hossenfelder.

Explore further: How bubble studies benefit science and engineering

More information: ATLAS experiment -- atlasexperiment.org/
Originally published by Oxford Blog at www.ox.ac.uk/media/science_blog/100329.html . Republished with permission.

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User comments : 32

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Bloodoflamb
Mar 29, 2010
This comment has been removed by a moderator.
mysticshakra
1.7 / 5 (17) Mar 29, 2010
What are mini black holes?

Fantasies.

What do we know about them?

Only what we invent.

What evidence do we have?

Ideas written on paper.

Science is a religion, black holes are one of its tenets of faith.
broglia
1.7 / 5 (13) Mar 29, 2010
As usually, Cern report doesn't say whole truth. It's true, by quantum mechanics black holes should evaporate fast. But by general relativity such black holes should be infinitelly stable. And the real black holes should remain somewhere in the middle - this is, what Cern physicists are really interested about.

By some popular theories (like string theory) the simultaneous aplication of both theories should lead into microscopic black holes, which should remain considerably more stable, then the Hawking model predicts.

In some theories (Randall-Sundrum model or recent Frampton's model) such tiny microscopic black hole even constitute (portion of) dark matter - so they must be infinitielly stable.

http://en.wikiped...ack_hole
http://arxiv.org/abs/1001.2308
http://arxiv.org/abs/1003.3356

Therefore the validity of these models depends not only on the fact, if LHC will prepare black hole - but on the fact, whether such black hole will remain sufficiently stable.
broglia
1.6 / 5 (13) Mar 29, 2010
Recently computer simulation was published (first of its kind, btw), which strongly supports model of micro-black holes. Due the presence of extradimensions, such black hole evaporates a much more slowly, then the Hawking model predicts, because the space-time arround black hole is compactified into itself.

http://news.scien...-01.html

In accordance with this model, the jet suppression was observed during previous attempts for black hole formation at RHIC and Tevatron. Physicists expect, they would observe another jet supression during first year of LHC experiments - we can say, they're nearly sure by it.

http://arxiv.org/.../0605062
http://iopscience.../12/S52/

Therefore the question is not, whether such black holes can be formed, but whether they will swallow Earth by avalanche-like mechanism. And this is still opened question - but I'd strongly reccomend not to solve it by LHC experiments directly from obvious reasons.
broglia
1.6 / 5 (13) Mar 29, 2010
What we know, dark matter can be really formed by substantial amount of tiny black holes - but these microblack holes are well known atom nuclei, which are essentially harmless for us.

But theory of strangelets developed by string theorists predicts, second generation of particles could form it's own heavy atoms, too. Recently one such atom nuclei was really observed during RHIC collisions temporarily - it contains strange quarks.

http://arstechnic...asma.ars

Because these strange atom nuclei are more heavy& dense, then the common atom nuclei, scientists expect, in mutual contact the matter would flow from normal atom nuclei into more dense ones like inside of binary stars. In this way, whole Earth (a cluster of tiny neutron stars, so to say) would be converted into cloud of tiny quark stars. It probable, we strongly wouldn't like this transition, despite it may not lead to feared black hole final state.
Shootist
3.4 / 5 (10) Mar 29, 2010
What are mini black holes?

Fantasies.



Really? You truly disbelieve this? Wow.

I have this philosopher's stone you might like, cheap. Turns lead into gold . . .
Shootist
3.4 / 5 (10) Mar 29, 2010
But by general relativity such black holes should be infinitelly stable.


SHOW ME THE MATH!

And if true there would be at least 6 microscopic primordial black holes within the orbit of Neptune. Where are they, oh sage?
CSC
1 / 5 (12) Mar 29, 2010
Going full ahead whith a machine that is capable of possibly destroying the earth, which this collider is depending on the physics, is about as stupid as setting off the first atomic bomb and not knowing if it would ignite the atmosphere of the planet for certain. This endeavor should be postponed until we know what the hell we are doing. Lower energy impacts would probably indicate a possible problem if ramped up slowly, but who the hell wants to wait around, theoretical physics with no empirical evidence awaits.
fuzz54
4 / 5 (6) Mar 29, 2010
capable of possibly destroying the earth, which this collider is depending on the physics
Nothing is possibly capable of destroying the earth. It either is or it isn't capable. We are going to run up against this issue again and again as our technologies allow higher energies to be put into one spot. Perhaps our understanding of electro magnetism isn't complete and attempts at laser fusion will create black holes. Maybe not. I'm not worried.
nixnixnix
1.4 / 5 (8) Mar 29, 2010
It seems that opinion on here is highly polarised. However, reading the article, it seems clear that the safety of the LHC is predicated entirely upon Hawking's black hole radiation theory being correct. That theory is an intrinsic part of many other clever people's work and so it would seem like fact. However, it has still never been tested. There is no empirical evidence for Hawking radiation. This being the case, I do think the doomsayers have a point. I guess on the plus side, if we're all still here in 2 years time then Hawking will have been proved correct - yay!

Nick
joefarah
1.5 / 5 (8) Mar 29, 2010
First - these "mini black holes" would not be stationary and will no longer be contained by the magnetic fields, and so will fly off into space in a fraction of a second.

Second - People keep saying nothing can escape the SS radius. That simply is not true. If it has a continuous net acceleration away from the center of the black hole, it can escape. However, if gravity from the black hole is the only force acting on it, it can escape. A couple of thought experiments to prove this:
(1) Two black holes with overlapping SS radii. The net acceleration on some particles will be zero along a path that leads to outside of the SS radii. Navigate this path with artificial acceleration (e.g. ion propulsion) and it escapes, not because of the ion propulsion but because of the balance of gravity.

(2) Take a rapidly spinning black hole which induces an extremely strong magnetic and/or electric field away from the center. This negates some gravity, allowing escape to be possible.
jj2009
1 / 5 (8) Mar 29, 2010
a more interesting question would be.. suppose the earth really was swallowed into a black hole, which then took its place and orbit. and suppose that process took 6 months, giving us time to escape the planet. would we still be able to survive? for example, building a very large spaceship and living on mars for a while..

MorituriMax
2.8 / 5 (4) Mar 29, 2010
@joefarah, oh how I wish you could give a rating of 0. Maybe I'll make the wish into a thought experiment.
seneca
1 / 5 (5) Mar 29, 2010
And if true there would be at least 6 microscopic primordial black holes within the orbit of Neptune. Where are they, oh sage?
You should ask here - I didn't developed, neither promoted this model...

http://ur.rutgers...eID=5182

Like I said already, I presume, these primordial micro-black holes are identical with common atom nuclei, which are harmless. But the theory of strange matter doesn't require strangelets to be very stable, if their reaction with common matter will be sufficiently fast.

My problem rather is, we have so many disaster scenarios developed and partially verified - but we still continue in LHC collisions, like all these publications and theories would never exist... It's evident, for Cern physicists no reason or experimental evidence is convincing enough and the LHC is out of public control already. So far I never read any response to objections of various skeptics - Cern simply doesn't communicate with the rest of world.
seneca
1 / 5 (6) Mar 29, 2010
...for example, building a very large spaceship and living on mars for a while..

Why not - but wouldn't be more easier just to simply stop LHC experiments until technology will allow us to manage them in safe distance from Earth? Why whole civilization should move to Mars just because of some sh*tty collider - wouldn't be easier to move only this collider there? We can only hope, if we would be able to manage such experiments, we would have some real usage for it too. Currently all collider experiments are completely useless waste of money for human society.

If scientists are so curious, why don't they study cold fusion, for example? It's much more mysterious and useful problem by now. The approach of physical community has simply no logic for me = they're all freaks out of public control from my perspective.
daywalk3r
3.8 / 5 (17) Mar 29, 2010
But by general relativity such black holes should be infinitelly stable.
...
In some theories (Randall-Sundrum model or recent Frampton's model) such tiny microscopic black hole even constitute (portion of) dark matter - so they must be infinitielly stable.
And by the theory of Santa Claus, there must be one living on the North pole. And he apparently must have some flying reindeers too!

Nothing is infinitely stable. Period.

So if by any theory infinite stability of anything is predicted, it either is a bad theory or a wrong conclusion / misinterpretation of the theory in question.
seneca
1 / 5 (6) Mar 29, 2010
Nothing is infinitely stable. Period.
Of course, you just revealed another limit of general relativity theory. By general relativity every sufficiently massive object would collapse into gravitational singularity without any evaporation. Whereas in quantum mechanics every object / wave packet would spread across whole Universe in sufficiently distant perspective. The objects of real world doesn't behave in such way - so there exist an apparent limit for both these theories.
daywalk3r
3.4 / 5 (10) Mar 29, 2010
Of course, you just revealed another limit of general relativity theory. By general relativity every sufficiently massive object would collapse into gravitational singularity without any evaporation.
Nope, relativity does not cover any of the specific processes involved in such scenarios. It is just the conclusions/models, based on GR, which "try" to cover it..

By general relativity every sufficiently massive object would collapse into gravitational singularity without any evaporation.
And this would be a very nice example of what I was talking about, at the end of my previous post :)
Lordjavathe3rd
1.8 / 5 (5) Mar 30, 2010
Mini black holes, "One great example is the mini black hole currently residing in the middle of our planet. It was put there by the LHC on accident and is also the culprit behind global warming, causing the earth to shift violently in global temperature change."
Lordjavathe3rd
1 / 5 (2) Mar 30, 2010
"Thus mankind finally got proof that man made global warming is real, thus proving the naysayers wrong and stupid."
ubavontuba
1 / 5 (6) Mar 30, 2010
These people know it might be dangerous, yet they continue anyway!

From Wikipedia: Mad Scientist:
...Mad scientists also, whilst definitely being intelligent, if not necessarily brilliant, usually fail to think things through to their conclusion...

Some excerpts from the LSAG (CERN safety committee) summary report:
Collisions at the LHC differ from cosmic-ray collisions with astronomical bodies like the Earth in that new particles produced in LHC collisions tend to move more slowly than those produced by cosmic rays. Stable black holes could be either electrically charged or neutral.

If stable microscopic black holes had no electric charge, their interactions with the Earth would be very weak. Those produced by cosmic rays would pass harmlessly through the Earth into space, whereas those produced by the LHC could remain on Earth.
... So just what do they think stable, neutral black holes, which remain on Earth, might do next?
ace61
1 / 5 (2) Mar 30, 2010
What if black holes are not a gravitational force that acts on all matter, but a collection of monopolar particles that together outweigh and attract the surrounding polarity all molecular, atomic, and sub atomic elements. Is not light just the ability to change the surface polarity of particles based on the reflection of the energy of the source. if an experiment was under way to produce an abundance of monopolar particles the community of knowledge that would be searching for this enlightenment would BUILD IN SAFEGUARDS(within nano seconds of the impact of the protons.... or within nanoseconds of the crossing the streams). This community of explorers will see the relevance of protecting the thought that had gone into this kind of expansion of mankind. If a "photo" or "etching" of the existance of sub-sub-atomic particles is the goal, then buildup of a steady stream, or collection of such monopolar particles would not be necessary. A look at monopolar activity is in our future
klawy
1 / 5 (2) Mar 30, 2010
To begin I would like to think about the scales involved... if you were to compare an atom with the so called visible universe it would be quite a noticeable difference in size. Then we do the same thing but in the opposite direction we compare an atom to the planck length and we find that the size ratios between the universe and an atom and an atom and the planck lenght are about equal. Then we take the planck lenght and make it 15 magnitudes smaller(i.e. 15*x = planck lenght) and we have the theoretical size(radius) of this minuscule black hole.
How can it to anyone with any kind of rational thinking believe that something this small could be stable? of what would this infinite small thing feed on? an atom compared to this "black hole" is as the size of a universe... not even another minuscule black hole can be engulfed (that is if it is not even smaller)
I still like to point out that the creation of or illusion of something of such a small size is foreseen by current physicaltheor
Mr_Man
4.8 / 5 (4) Mar 30, 2010
Going full ahead whith a machine that is capable of possibly destroying the earth, which this collider is depending on the physics, is about as stupid as setting off the first atomic bomb and not knowing if it would ignite the atmosphere of the planet for certain. This endeavor should be postponed until we know what the hell we are doing. Lower energy impacts would probably indicate a possible problem if ramped up slowly, but who the hell wants to wait around, theoretical physics with no empirical evidence awaits.


I would be willing to bet that the hundreds of physicists that are working on the project wouldn't want to put their families (or the rest of the world) at risk of destruction if they knew there was even a slight possibility that the micro black hole would destroy the Earth.

Fear doesn't come from one's own ignorance, fear comes from one's unwillingness to accept a possible truth.
ubavontuba
1 / 5 (6) Mar 30, 2010
I would be willing to bet that the hundreds of physicists that are working on the project wouldn't want to put their families (or the rest of the world) at risk of destruction if they knew there was even a slight possibility that the micro black hole would destroy the Earth.

Fear doesn't come from one's own ignorance, fear comes from one's unwillingness to accept a possible truth.
Oh brother. Like scientists have NEVER made an error which cost the lives of innocents. Give me a break.
rjhuntington
1 / 5 (2) Apr 04, 2010
What are mini black holes?

Fantasies.



Really? You truly disbelieve this? Wow.

I have this philosopher's stone you might like, cheap. Turns lead into gold . . .


I don't think you'll sell that stone to a skeptic! He's not buying any of it. Neither am I. Black holes are a mathematical fantasy, observable only in clever equations.
rjhuntington
2 / 5 (4) Apr 04, 2010
I find it astounding that so much of science has been surrendered to mathematics. Astrophysics has devolved from a real science based on experimentation and observation into pseudoscience based entirely on mathematical equations.

Granted, it's not easy to observe the center of a galaxy, at least not yet. But fixing up a theory when observable phenomena do not support it by massaging the equations until they give the desired result even when it means postulating physically impossible unobservable objects with infinite properties is not science, it is rubbish.

If the observable facts do not fit the theory, then the theory is falsified. Sooner or later, we are going to have to go back to real science, observation, testing, experimentation. Mathematics are useful, but not the be-all/end-all of science. Just because someone can come up with a clever system of equations doesn't mean they model reality!
hush1
1 / 5 (1) Apr 04, 2010
'Life' doesn't have a very good working definition.

Let's pretend we finally have a good working definition that suits everyone and is more readily accessible to science - it's methodology.

Now let's postulate the only reason we haven't encountered 'Life' similar to ours, is because that 'Life', other than ours, managed similar LHC experiments, experimentally proving the existence of mini black holes - successfully. The only drawback was the life-span expectancy of the mini black holes was underestimated.

Dark Matter + Dark Energy = Dark Humor :)
Amgartsh
5 / 5 (3) Apr 04, 2010
spoken like a true college dropout rjhuntington...
mathematics is simply a way to quantify the observations and experiments we do. All of the equations used in a given experiment ARE deduced from observation at some point, and manipulating an equation to suit an observation is how we're able to model a given event, and thus make a theory about it. Obv this can be proved wrong, but when it comes down to it science is trial and error.
Pretty much what you're saying is we shouldn't be doing thought experiments because they rely too much on math. Almost every major achievement in physics in the past century has been, or based on, a thought experiment. What is Einstein's Relativity if nothing more than a thought experiment based on the Lorentz Transformations?
Shootist
3 / 5 (4) Apr 04, 2010
But by general relativity such black holes should be infinitelly stable.
...
In some theories (Randall-Sundrum model or recent Frampton's model) such tiny microscopic black hole even constitute (portion of) dark matter - so they must be infinitielly stable.
And by the theory of Santa Claus, there must be one living on the North pole. And he apparently must have some flying reindeers too!

Nothing is infinitely stable. Period.

So if by any theory infinite stability of anything is predicted, it either is a bad theory or a wrong conclusion / misinterpretation of the theory in question.


A proton seems to meet the criteria for "infinite stability".
Shootist
3 / 5 (4) Apr 04, 2010


I don't think you'll sell that stone to a skeptic! He's not buying any of it. Neither am I. Black holes are a mathematical fantasy, observable only in clever equations.


So what, exactly, resides in the center of active galaxies?

Why, exactly, would you say singularities are 'clever equations' when GR is the most verified of all physical theories?
stealthc
1 / 5 (5) Apr 04, 2010
Just for the record, not only do I agree with the concept of the mini black hole, I feel that the LHC will discover these between 7-14 tev.

I also feel that with further investigation we will find that eventually a black hole will devour an entire galaxy, perhaps even more, but can only drift away in nothing or a net negative environment of fuel vs. radiation, and therefore these are actually a stable element of our universe which will regulate expansion. Because of this there will also be no specific big crunch of everything (it'll take alot but not everything) because black holes eating each other will still produce this radiation, which will eventually turn into other forms of matter/energy (perhaps not what we expect; but the energy will still be there none-the-less).

If the big crunch does happen, it is likely that a black hole will reach such a large state that as mass increases so does the power of this big bang. This is what I think they will find.
daywalk3r
1.7 / 5 (6) Apr 05, 2010
A proton seems to meet the criteria for "infinite stability".
Only if the conditions at its location infinitelly remain within certain limits. Which in reality, they most certainly will not.. Good try though ;-)