Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Micro-Black Holes Make Poor Planet Killers

timothy posted more than 4 years ago | from the they-don't-even-make-good-nightclubs dept.

Space 314

astroengine writes "Physicists are getting excited about the possibility of micro-black holes (MBH) being produced by the LHC and an international group of researchers have done the math to see what kind of impact they could have on the Earth. Unfortunately, if you're a megalomaniac looking for your next globe-eating weapon, you can scrub MBHs off your WMD list. If a speedy MBH is produced, flying through our planet, it will only have a few seconds to accrete the mass of a few atoms. It would then be lost to space where it will evaporate. If a slow MBH is produced, dropping into the Earth where it sits for a few billion years, the results are even more boring."

Sorry! There are no comments related to the filter you selected.

More Mass = More Suck (5, Funny)

amazeofdeath (1102843) | more than 4 years ago | (#30085686)

I guess I know what kind of girl to look for now ;)

Re:More Mass = More Suck (-1, Troll)

Anonymous Coward | more than 4 years ago | (#30085816)

You seem intrigued in micro black holes. Now that you are interested in girls, try the front.

I have a VERY pertinent link (-1, Troll)

Anonymous Coward | more than 4 years ago | (#30086048)

This [goatse.cz] is what happens [goatse.cx] when a micro black hole [goatse.ch] is observed too often. Sorry if all the links are down. I tried!

Re:More Mass = More Suck (1, Offtopic)

ArsenneLupin (766289) | more than 4 years ago | (#30086062)

You seem intrigued in micro black holes. Now that you are interested in girls, try the front.

Well, the "more suck" theory would probably work for men too...

Re:More Mass = More Suck (-1, Troll)

Anonymous Coward | more than 4 years ago | (#30085824)

and more mass = deeper suckage

Re:More Mass = More Suck (0)

Anonymous Coward | more than 4 years ago | (#30086088)

Is this going to affect Meatloaf's work on the Linux kernel getting into the main branch?

Re:More Mass = More Suck (2, Funny)

elrous0 (869638) | more than 4 years ago | (#30086134)

I guess it turns out that size DOES matter.

Lots of speculation. (-1, Redundant)

Anonymous Coward | more than 4 years ago | (#30085688)

Like a lot of advanced theoretical physics, this is nothing but speculation heaped upon more speculation.

Just because their math suggests this to be the case, doesn't mean that it actually is.

With some of the math used, there are literally only three or four other theoretical physicists in the world who can "comprehend" it. At that point, one has to wonder if they actually do comprehend it, or just claim to.

Re:Lots of speculation. (3, Interesting)

Sockatume (732728) | more than 4 years ago | (#30085732)

Actually it's freshman-level physics. Calculating how quickly a micro-black-hole would accumulate mass strikes me as a great undergrad tutorial question.

Re:Lots of speculation. (5, Insightful)

MindKata (957167) | more than 4 years ago | (#30085928)

"Calculating how quickly a micro-black-hole would accumulate mass strikes me as a great undergrad tutorial question."

Which implies using existing theories to calculate it. What I think the grand parent post is saying is that we don't know for sure our current theories are all correct. After all, if we knew it all 100% correctly, there wouldn't be any need to build the LHC.

Scientific evidence accumulates over time. In science, its extremely hard to say 100% correct and be very careful of anyone who claims different.

Our current theories are our best current understanding of the universe and they do indeed work well. But we cannot be 100% sure. In the case of creating a black hole we won't know for sure until we create one under the conditions in the LHC (which due to the grouping of particle collisions in the LHC is different from a single high speed collision happening in the upper atmosphere).

Throughout the history of science we can see time and time again where theories were overturned. We therefore cannot assume all our current theories are correct under all possible conditions. There could be factors we are so far ignoring.

The problem is, the creation of a black hole in the LHC is kind of a unique experiment, as most wrong answers in science don't have such horrific results if our current theories are wrong.

Re:Lots of speculation. (0)

Anonymous Coward | more than 4 years ago | (#30085988)

Let's say the current theories predict a gradually growing black hole, but what if in reality it's going to grow exponentially?

Re:Lots of speculation. (1)

MyLongNickName (822545) | more than 4 years ago | (#30085932)

How do we know with certainty how a black hole behaves? It would seem to me that studying something from millions of light years away where we only get indirect evidence is not the same of plunking one down in the middle of the earth and experiencing it firsthand.

Re:Lots of speculation. (1)

Sique (173459) | more than 4 years ago | (#30085994)

We are talking Micro Black Holes here, and those appear in our atmosphere quite often. So no, we don't need to look at far away galaxies to make some observations.

Re:Lots of speculation. (1)

MyLongNickName (822545) | more than 4 years ago | (#30086314)

Interesting. I wasn't aware that this was the case. Can you point me to any good discussions on studies on these black holes or even if they have truly been detected. Wikipedia seems to indicate that they are only theoretical...

Re:Lots of speculation. (5, Insightful)

The_Wilschon (782534) | more than 4 years ago | (#30086500)

The argument goes like this: There are plenty of cosmic rays which impact our atmosphere, the other planets in the solar system, the sun, other stars, everything, with energies across a huge spectrum, including LHC energies. Either the LHC will produce MBH or it will not. If it will, then cosmic rays also produce MBH, and do so without destroying any of the things we can see in the sky, so MBH from the LHC would similarly not destroy the earth. If the LHC will not produce MBH, then we have nothing to worry about in that regard anyway.

This argument works for just about any Earth destroying LHC scenario, except, I suppose, the time traveling killer Higgs ;)

Re:Lots of speculation. (4, Insightful)

stjobe (78285) | more than 4 years ago | (#30085756)

Ah, the fear of the unknown. Yes, a classic. "I don't understand it, and I don't believe that they do either".

I've got news for you; this is as good (or should i say precise) model of these things as you are going to get right now. It's the cutting edge of our understanding of how MBHs work, and _that_ understanding in turn depends on a quite large, quite solid foundation of math and physics.

So please, this isn't speculation, it's SCIENCE.

Re:Lots of speculation. (1, Redundant)

Stan Vassilev (939229) | more than 4 years ago | (#30085980)

It's the cutting edge of our understanding of how MBHs work, and _that_ understanding in turn depends on a quite large, quite solid foundation of math and physics.

So please, this isn't speculation, it's SCIENCE.

I thought science is when you confirm your theories by experimentation. I didn't know we've had the chance to confirm the precise mechanics of black holes via experimental observation.

At that stage, calling it "solid foundation" and deflecting doubts sounds to me more like religion, and not science.

The main lesson of science is to be humble, all scientific models are "incorrect" in the long term. While I don't find the LHC is a threat, the outcome of its tests will very likely surprise both sides of this discussion.

Re:Lots of speculation. (1)

Interoperable (1651953) | more than 4 years ago | (#30086496)

I thought science is when you confirm your theories by experimentation.

Science is the interplay between theory and experiment. Developing fields don't have to rigidly follow the hypothesis->experiment->modification->hypothesis->etc. model or risk being rejected as unscientific. Theoreticians and researchers can make valuable advances on untested theoretical work or unexplained experimental results to try to fill out new, poorly understood areas. The popular perception that science must evolve according to rigid principles is simply false. Like any other discipline it evolves organically and blunders in incorrect directions are often extremely valuable.

The important element that separates the scientists from the crackpots is lively debate and exchange with the broader community, not dogmatic pursuit of a rigid notion of scientific method. Everything within that debate is science. (Peer-review is the formalized structure of the debate and, while it's very far from perfect, does a decent job of filtering out the noise.)

Re:Lots of speculation. (0)

Wooky_linuxer (685371) | more than 4 years ago | (#30085998)

And yet it could be wrong. That's all the previous posts are saying. What would've happened if people got attached to the cutting edge understanding of gravity and electromagnetics during the late 1800's? Stop being a scientific arse and admit that you - or scientists - don't know everything. If they did, there would be no point in building the LHC after all. Science is an exercise in LEARNING.

Re:Lots of speculation. (1, Insightful)

Anonymous Coward | more than 4 years ago | (#30086154)

Well yes but just because something could be wrong doesn't mean we should give no weight at all to their proposed mathematical model. That's like saying that our current understanding of gravity and electromagnetics (or evolution or whatever) COULD be wrong, so let's take all this egghead science stuff with a grain of salt. Everyone will freely acknowledge this, but like ID folks (I'm a biologist so pardon me for leaping to this example) the logical fallacy is then, "Well you could be wrong, and I could be wrong, so let's give equal credence to both our ideas." Which is silly, because just because two things might or might not be true doesn't mean they might or might not be true equally. Similarly, if a world-renowned physicist says something, and I say he might be wrong, everyone knows that already, but since he's put together a good model of a phenomenon based on our current understanding of how the universe works, there's no reason to assume it's all speculation and hand-waving.

Re:Lots of speculation. (3, Insightful)

TheRaven64 (641858) | more than 4 years ago | (#30086164)

It could be wrong, but it can only be wrong in one direction. The kind of collision that the LHC is going to be producing happens all the time in the upper atmosphere as cosmic rays hit. There are three possibilities:
  1. The theory is approximately correct.
  2. Micro black holes aren't formed at all at this energy level.
  3. Micro black holes evaporate much faster than expected (unlikely, because this would produce more radiation than we observe).

Re:Lots of speculation. (3, Insightful)

Yvan256 (722131) | more than 4 years ago | (#30086018)

In this case it's quite different. It's not religious zealots crying wolf at something they don't understand. It's rational people, some of them scientists, saying that we really don't know for sure, that our current knowledge could be flawed. A real scientist should always be ready to question our current knowledge.

Another way to put it: if we were so sure that what we know is 100% correct then we wouldn't need to build the LHC to test our theories in the first place.

Re:Lots of speculation. (0, Flamebait)

asliarun (636603) | more than 4 years ago | (#30086042)

Please don't go about shaking our belief systems. We need these uncertainties to keep being fearful of our vengeful gods.

"...I have a constant fear that somethings always near
I have a phobia that someone's always there
Fear of the dark, fear of the dark..."

Re:Lots of speculation. (1)

Trails (629752) | more than 4 years ago | (#30086128)

I've got news for you; this is as good (or should i say precise) model of these things as you are going to get right now. It's the cutting edge of our understanding of how MBHs work, and _that_ understanding in turn depends on a quite large, quite solid foundation of math, physics and observations.

Fixed that for ya.

Re:Lots of speculation. (3, Interesting)

sjames (1099) | more than 4 years ago | (#30086508)

The math that suggests that a quantum black hole will evaporate in an instant may be fairly advanced, but the math showing that even if Hawking is completely wrong such a black hole would have no noticeable effect on the earth over a 13 billion year period is not all that advanced.

Then there's simple logic. While LHC may produce the most powerful collisions ever under our control, nature routinely produces much more powerful collisions including cosmic rays. Clearly, in billions of years none of this has resulted in a planet eating black hole.

But what if slow black holes collide? (3, Funny)

Anonymous Coward | more than 4 years ago | (#30085690)

Sorry, but I really feel the need to be afraid of something irrational.

Re:But what if slow black holes collide? (0, Troll)

b0ttle (1332811) | more than 4 years ago | (#30085734)

They will merge into a slighter bigger MBH.

Re:But what if slow black holes collide? (5, Funny)

bcmm (768152) | more than 4 years ago | (#30085944)

Have you considered religion?

Re:But what if slow black holes collide? (3, Informative)

Alain Williams (2972) | more than 4 years ago | (#30085972)

To do this they need to hit each other first. Their cross section is tiny (10^-35m, size of an electron is 16^-15m), they will be moving slowly (about 11km/second if they are created with zero velocity at CERN) - so the chance of them hitting each other is small. If they came across an atom - most of that is empty space; the protons & neutrons are mostly empty space (between the quarks) to something as small as the black hole.

3rd Option (0, Redundant)

Kryptonian Jor-El (970056) | more than 4 years ago | (#30085730)

Or it destroys the whole planet!!!!111!!11!!1!!

Re:3rd Option (1, Insightful)

laejoh (648921) | more than 4 years ago | (#30085792)

You'd need a MDD [wikipedia.org] , not a MBH!

Poor MBHs (2, Funny)

Rik Sweeney (471717) | more than 4 years ago | (#30085742)

Ironically, it sucks to be them :)

Re:Poor MBHs (4, Funny)

electricbern (1222632) | more than 4 years ago | (#30085788)

When will people see the light? MBHs don't suck so bad.

Re:Poor MBHs (0)

Anonymous Coward | more than 4 years ago | (#30085966)

When will people see the light?

If they are rotating BHs, as soon as enough mass accumulates in the accretion zone and gets heated to the point that it emits visible radiation.

Re:Poor MBHs (0)

Anonymous Coward | more than 4 years ago | (#30085822)

not irony. not even Morissette irony.

Good article, won't stop the panic of the idjits (3, Insightful)

Phoenix (2762) | more than 4 years ago | (#30085750)

Sadly however, people will read this article and will still freak out about how the LHC is going to doom us all.

Re:Good article, won't stop the panic of the idjit (0)

Anonymous Coward | more than 4 years ago | (#30086038)

Interesting. I haven't met a serious person who was freaked out by the black holes which could possibly generated by the LHC. Actually they are more afraid of the weak economy or the pigeon-flu (which they are more afraid of the vaccine than the actual disease). I guess the most of them who actually know that there is an LHC do not really think a lot about it as there are more pressing matters.

Re:Good article, won't stop the panic of the idjit (1)

elrous0 (869638) | more than 4 years ago | (#30086186)

Yeah, but those are the same people who think aliens are traveling across the vast distances of interstellar space to play ass-grab with rednecks in trailer parks. You have about as much chance of educating the unwashed masses as you do of convincing them to become washed masses. Best to keep sedating them with sports.

Re:Good article, won't stop the panic of the idjit (4, Funny)

L4t3r4lu5 (1216702) | more than 4 years ago | (#30086194)

How could we not read it like that?!

"... if you're a megalomaniac looking for your next globe-eating weapon,... a speedy MBH ... flying through our planet... will only have a few seconds to accrete the mass of ... the Earth ."

WE'RE DOOMED!

But that's how they killed Vulcan... (4, Funny)

JoeDuncan (874519) | more than 4 years ago | (#30085752)

... I guess someone forgot to tell Nero

How much red matter does the LHC use anyway?

Re:But that's how they killed Vulcan... (4, Funny)

Anonymous Coward | more than 4 years ago | (#30086262)

Too Soon. Not Funny.

Evaporate? (1)

imamac (1083405) | more than 4 years ago | (#30085786)

And where exactly does the MBH evaporate to? Or is that all part of the mystery?

Re:Evaporate? (1)

John Hasler (414242) | more than 4 years ago | (#30085802)

> And where exactly does the MBH evaporate to?

In all directions.

Re:Evaporate? (1)

Rik Sweeney (471717) | more than 4 years ago | (#30085914)

What happens to everything it's sucked in? Does that get spat out again?

Re:Evaporate? (0)

Anonymous Coward | more than 4 years ago | (#30085984)

Not exactly, it just becomes part of the rest of the universe.

Re:Evaporate? (1)

Thanshin (1188877) | more than 4 years ago | (#30086008)

Everything sucked in is already on Earth. About thirty years ago. Saving the whales, or somesuch.

Re:Evaporate? (4, Informative)

gclef (96311) | more than 4 years ago | (#30086100)

Mass = Energy...it evaporates by emitting other forms of energy (light, etc).

Re:Evaporate? (4, Informative)

Maximum Prophet (716608) | more than 4 years ago | (#30086242)

Photons pop out of the vacuum all the time. A photon and an anti-photon (or do they call it a virtual photon) will appear at the same time, and as long as the pair doesn't stick around longer than the mass * Plank's constant, conservation of mass is preserved.

If the photon and anti-photon appear at the edge of a black hole, sometimes the photon goes off, and the anti-photon gets sucked into the black hole where it cancels some of the mass of the black hole. Thus it looks like the BH is radiating and evaporating, but nothing actual leaves the BH.

*Note: I've left out some details, and my terminology might be off.

Re:Evaporate? (0)

Anonymous Coward | more than 4 years ago | (#30086360)

The thing I'd add to that is that there are no anti-photons -- photons are their own anti-particle.

What may be clearer is to consider electron-positron pairs instead, where there is a clearly-defined antipartner. In that case some of the electrons fall into the hole, some of the positrons fall into the hole, and the rest go swanning their sweet way across the universe. (In the case of a positron, to soon explode in a brief burst of gamma radiation when it hits an electron.)

Re:Evaporate? (0)

Anonymous Coward | more than 4 years ago | (#30086016)

Sadly, evaporation is an accepted black hole physics concept. It has to do with loss of mass over huge amounts of time from something like friction between the event horizon and normal space, if I recall correctly. Wikipedia has crunchy equations on it:

http://en.wikipedia.org/wiki/Hawking_radiation#Black_hole_evaporation [wikipedia.org]

Re:Evaporate? (5, Informative)

ChowRiit (939581) | more than 4 years ago | (#30086206)

Particles. A hand-waving description of what happens is as follows:

Pairs of particles (one matter, one antimatter) form randomly near the event horizon. One quantum-tunnels out of the black-hole and so appears to an observer outside the black-hole to have been emitted. Therefore, to conserve energy, the other particle must have negative energy and thus the black-hole loses a tiny parcel of energy (and thus mass).

The main point is that, because the particle was formed near the event horizon and didn't come from the black-hole itself, it carries no information out - thus, while the black-hole loses mass, no information can escape.

Re:Evaporate? (1)

TheRaven64 (641858) | more than 4 years ago | (#30086224)

Where does water evaporate to? Black hole evaporation is not quite the same; it's the release of Hawking radiation, rather than the release of gaseous water molecules, but it's the same general idea. The substance of the black hole is converted (slowly) into radiation and escapes. Because energy is just a much less dense version of matter, this means that the black hole loses mass until eventually it doesn't have enough left to remain a black hole. There's no magic or mystery any more than there is in the slow loss in mass when tritium glows.

Re:Evaporate? (1)

Maximum Prophet (716608) | more than 4 years ago | (#30086230)

Photons pop out of the vacuum all the time. A photon and an anti-photon (or do they call it a virtual photon) will appear at the same time, and as long as the pair doesn't stick around longer than the mass * Plank's constant, conservation of mass is preserved.

If the photon and anti-photon appear at the edge of a black hole, sometimes the photon goes off, and the anti-photon gets sucked into the black hole where it cancels some of the mass of the black hole. Thus it looks like the BH is radiating and evaporating, but nothing actual leaves the BH.

*Note: I've left out some details, and my terminology might be off.

Do they mean a black hole or a singularity? (3, Interesting)

jimboindeutchland (1125659) | more than 4 years ago | (#30085796)

I'm sure there's somebody on /. who can answer this:

Correct me if I'm wrong, but I thought to be a black hole you had to be 2 things.
1. a singularity
2. heavy/massive enough to stop anything from escaping

If you've got a singularity (worst case in our example) that's the mass of the earth, how's that supposed to stop any light/matter/etc escaping? It's not massive enough!

or am I missing something.

Also, please excuse my lack of correct terminology. IANAAP

Radius (5, Informative)

Moraelin (679338) | more than 4 years ago | (#30085900)

Well, the key isn't just mass, but also radius. Gravity (I'll go newtonian, just because I'm lazy) increased linearly with mass, but decreases with the square of the radius. So for example, if you packed something the mass of Earth in just half the size of Earth, the gravity on the surface would be 4 times that of Earth. Squeeze it into a quarter of the size of Earth and get 16 times the gravity on the surface. Squeeze it small enough and you have a black hole.

If you do the proper maths, the Schwarzschild radius of a black hole with the mass of Earth is about 9mm.

Which really means, don't think something that will suck matter and bend light spectacularly all the way to Alpha Centauri. It means that if light happens to go within 9mm of that singularity, it ain't coming out. But farther away, it's still a body with the mass of Earth. The moon's orbit will still have the same radius for example.

Re:Radius (1)

jimboindeutchland (1125659) | more than 4 years ago | (#30085942)

excellent explanation, thanks :)

Re:Radius (1)

imamac (1083405) | more than 4 years ago | (#30086000)

Incredibly helpful. Thank you!

Re:Radius (1)

jlebrech (810586) | more than 4 years ago | (#30086078)

Just made me think, one could make a tiny space station with the same gravity as earth. Am I right?

And it wouldn't have to spin to create reverse gravity.

Re:Radius (3, Interesting)

Animaether (411575) | more than 4 years ago | (#30086330)

you'd have to figure out a way to suspend it inside your spaceship and travel along with your spaceship.. which would have to be spherical because different gravitational magnitudes being exerted on different parts of your body has got to be uncomfortable.

Even with it being spherical, your feet would get a noticeably larger gravitational force than your head.. blood circulation might become an issue. Somebody with too much time on their hands could probably work out the 'safe' minimal radius of the sphere surface you'd be walking on.

Re:Radius (1)

Kenoli (934612) | more than 4 years ago | (#30086510)

All we need now are engines powerful enough to move something as massive as Earth.
Oh, wait...

Re:Radius (1)

L4t3r4lu5 (1216702) | more than 4 years ago | (#30086334)

Ok, so what would happen if one of these super-mini black holes were to, say, have matter thrown at them from opposite directions at close to the speed of light, with the equivalent energy of a family car hitting an immovable object at 1000MPH? Would that potentially cause it to grow?

IANATP, but you seem to be quite well informed.

Re:Do they mean a black hole or a singularity? (1)

vadim_t (324782) | more than 4 years ago | (#30085910)

It will trap light alright, just not at the Earth's radius.

If all of the Earth was squeezed into a tiny point the gravity would remain the same for things that are where the ground used to be.

But as you get closer to it, it will grow, until you can't escape anymore.

Re:Do they mean a black hole or a singularity? (1)

Ihlosi (895663) | more than 4 years ago | (#30086034)

If you've got a singularity (worst case in our example) that's the mass of the earth, how's that supposed to stop any light/matter/etc escaping? It's not massive enough!

A singularity with one Earth mass will be _tiny_. That means light and matter can get so close to it that they won't be able to escape. Of course, if you're one Earth radius away from it, it'll just exert as much gravitational pull as the real Earth.

Re:Do they mean a black hole or a singularity? (1)

Wooky_linuxer (685371) | more than 4 years ago | (#30086036)

substitute massive for dense. BH are dense objects, but they don't need to be massive. As long as you squeeze enough mass in a tiny enough place - hence the theoretical possibility of MBH forming - you have a black hole (pardon me if I oversimplified this).

Re:Do they mean a black hole or a singularity? (1)

jellomizer (103300) | more than 4 years ago | (#30086070)

Well lets think for a 2D black hole. As 3d Ones are hard to picture in your head. So Imagine a plane of streachy rubber. That will represent normal space time. Then you take 2 objects say a bowling ball and a pin needle. You put the bowling ball down its massive weight has distored space time and made a large hole where an object say Rowling a marble across the plain when approaching the bowling ball would fall in the well. Next you take a pin needle you create a very small hole with the same angles as the bowling ball but much smaller you take that marble and role it its gravity force will either roll right over it and not causing a major problem or attract the smaller pins gravitational force and just make the marble just a little bit more massive but it wouldn't create a black hole.

Re:Do they mean a black hole or a singularity? (5, Informative)

necro81 (917438) | more than 4 years ago | (#30086142)

In principle, any mass, if packed densely enough, could become a black hole. For each mass - from a cluster of atoms to an entire galaxy - there is a calculable quantity called the Schwarzschild radius [wikipedia.org] . If you could somehow pack the mass so that it fit inside a volume smaller than that mass's Schwarzschild radius, the force of gravity would invariably overcome all other forces and cause the mass to become a singularity. The Schwarzschild radius also defines the "edge" of the black hole - if anything, including light, gets closer than one Schwarzschild radius from the central mass, it will not be able to escape. In other words, at the Schwarzschild radius, the escape velocity [wikipedia.org] is the speed of light.

It is easy to see how the core of a really big star could collapse on itself in a supernova - there's just so much mass, coupled with the force of the explosion. However, our own sun could become a black hole - if some as-yet unknown physical process could squeeze its entire mass into a 6-km diameter sphere. The Schwarzschild radius of one solar mass is about 3 km.

It is important to note that, were this to happen tomorrow, the Earth and the other planets would continue to orbit the black hole sun exactly as they have done for billions of years. The gravity of the sun hasn't changed, because its mass hasn't changed. If you were, however, unfortunate enough to come within 3 km of the center of the black hole sun, that's the last the universe would ever see of you. (As a practical matter, you'd be doomed long before then, simply because no rocket would be powerful enough to bring you away once you got closer than a few thousand kilometers. To escape the black hole sun once you were, say, 3.1 km away, you would need to somehow achieve a speed near to the speed of light, which we simply can't do.)

It is also important to note that you would not be sucked into a black hole if you came within 3 km of the center of the sun as it exists today, shining hot and bright. This is because 99.999% of the mass of the sun lies outside of that 3 km radius and so "doesn't count" in terms of the force of gravity. Aside from instantly transforming into plasma from the heat, you would actually feel far less gravity than you would on the Moon. (For reasons why, see here [wikipedia.org] .) Remember: a black hole would exist only if you could compress the whole mass of the sun into that 3-km radius spherical volume. This can be applied to just about any mass. The Schwarzschild radius of the Earth is about 9 mm - smaller than a grape. This gives you a sense of how densely you'd have to pack things if you wanted to make an Earth-mass black hole. For a pair of protons smashed together at high energies - as in the LHC - I think you need to bring in other areas of physics than just general relativity. Suffice to say the Schwarzschild radius would be much, much, much smaller than the size of a proton, which in turn is much, much, much smaller than the size of an atom, which is much smaller than the distance between atoms in most solids. So in order for a micro-black-hole to accumulate mass, it would need to pass very close, on the order of its Schwarzschild radius, to the nucleus of another atom. At the length scales we are talking about, that's about as likely as me randomly shooting off a bb gun and hitting a passing bird a kilometer away.

So rest easy, the world isn't about to end.

I apologize for the long answer, but I hope it has answered your question.

Re:Do they mean a black hole or a singularity? (3, Informative)

ChowRiit (939581) | more than 4 years ago | (#30086144)

A black hole is any body tightly packed enough that its escape velocity is greater than the speed of light. Because material, as a result of this, can ONLY travel towards the centre of mass (outward travel, sideways travel and staying stationary are all forbidden this therefore HAS to form a singularity, as matter is all forced to head towards and occupy a single point.

The distance from the object where the escape velocity drops below the speed of light is the event horizon (aka the Schwarzschild radius), within this sphere* no light can escape so we call this sphere the black hole. In the centre of it is the singularity, which is the "true" black-hole.

All objects have Schwarzschild radii, however this radius is only a "real" radius if it exceeds the radius of the object. Wikipedia claims the Schwarzschild radius of the Earth is 9mm, so Earth would form a black-hole itself if it were compressed to smaller than 9mm in radius.

The key point is that a "black-hole" is not an object, per se, but a region of space from which light cannot escape. The "object" would be the singularity in the centre. From outside the black-hole, there's no real difference from a star of the same mass in terms of gravity.

*rotating black holes have a slightly different shape, depends on the speed of rotation.

Re:Do they mean a black hole or a singularity? (1)

Aahzimandious (1424393) | more than 4 years ago | (#30086180)

I hope this helps? And.. as I understand it... Mass = Density * Volume Singularity: Mass's volume has reached zero. Blackhole: The area that a singularity from which light cannot escape from. If you took the mass of the Earth and compressed it's volume to about the size of a marble you'd get a 'blackhole/singularity'.

As if! (0, Troll)

Abuzar (732558) | more than 4 years ago | (#30085842)

Sure, everyone's a physics expert even when dealing with completely unknown phenomena and experiments conducted for the first time in human history.

Of course they're saying there is no cause for concern, it's their job that's on the line. Risks to humanity, the planet etc. be damned, we want our LHC!

Re:As if! (2, Insightful)

somersault (912633) | more than 4 years ago | (#30085904)

I heard this months ago on /. , it's hardly news to those who had actually been following things.

If there was any serious cause for concern, this wouldn't be going ahead. I doubt every scientist working on the project is also desiring to commit suicide/genocide/planetacide/whatever.

Re:As if! (1)

Thanshin (1188877) | more than 4 years ago | (#30085956)

I doubt every scientist working on the project is also desiring to commit suicide/genocide/planetacide/whatever.

I just imagined a collective mad laughter, chorused by the entire LHC staff.

On freakishly perfect synchrony.

Like machines.

Or robots!

Oh my god!

Re:As if! (0)

Anonymous Coward | more than 4 years ago | (#30086168)

If they had not built the LHC, they would have used the money for other scientific projects. You could imagine (could you?) that they would then have just different jobs.

Even though. The people who built the LHC and those who might use it in future are not equal sets of people. The CERN is such a big institution, that there is fluctuation. Some scientists are even just guests there for some time, so do you really think that all of them (including those who work abroad and those who have not got enough funding of their projects because of the LHC will just quietly stand by and say nothing?).

All people who argued that the LHC is a World Dooms Machine are not physicists especially not particle physicists so why should they understand it better than particle physicists? And remember not all particle physicists work for CERN. There are others and the all say its save.

Re:As if! (1)

ArsenneLupin (766289) | more than 4 years ago | (#30086348)

Of course they're saying there is no cause for concern, it's their job that's on the line. Risks to humanity, the planet etc. be damned, we want our LHC!

Fortunately, we can rely on our trusty baguette dropping birds [slashdot.org] to save humanity from its certain fate by annihilation. Vive la France!

Earth novel? (0)

Anonymous Coward | more than 4 years ago | (#30085872)

But http://en.wikipedia.org/wiki/Earth_(novel) [wikipedia.org] was such a good book, why must MBH be so boring in reality?

Re:Earth novel? (1)

arethuza (737069) | more than 4 years ago | (#30086116)

Oh - that's the one where the 3rd world war was everyone versus the bankers armed with cobalt bombs lurking under Swiss Alps?

Famous last words (0)

Anonymous Coward | more than 4 years ago | (#30085878)

This is completely safe. We know what's going to happen, that's why we're building these expensive machines to perform experiments. (Yes, I know that doing something catastrophic with the LHC is very very unlikely, but it's an experiment after all. It's not like scientists have never fucked up before, is it?)

WMD not yet, but perhaps someday? (1)

burtosis (1124179) | more than 4 years ago | (#30085902)

I don't doubt the science behind the LHC or the scenarios presented. But I wonder if it is possible to make a device (probaby insanely expensive and massive like the LHC) whereby the MHB could be accurately force fed like a veal calf untill it hit a critical point (tons - ktons - Mtons) of mass and would be a worthy earth destroyer. Nuclear weapons just destroy a little area and make the world far less habitable. A good size black hole could

Study Funded By Black Hole Companies (4, Funny)

tjstork (137384) | more than 4 years ago | (#30085930)

What people don't realize is that this study was funded by companies that produce black holes.

Re:Study Funded By Black Hole Companies (0)

Anonymous Coward | more than 4 years ago | (#30086002)

Yeah move along guys, nothing to see here - just Big BH trying to lull the public into complacency again.

Re:Study Funded By Black Hole Companies (1)

sakdoctor (1087155) | more than 4 years ago | (#30086432)

A company that produces black holes needs a bailout. It's too big to fail.

Black holes are fiction (-1, Troll)

clone53421 (1310749) | more than 4 years ago | (#30085976)

You can't crush something with a force that's weaker than the repulsive force that's holding it apart.

Gravity is much, much weaker than the subatomic electrostatic forces that hold subatomic particles apart.

In essence, what you're claiming in a black hole is a neutron star – a single massive nucleus – packed together as tightly as is physically possible for matter to be packed. This is impossible on the most basic level: the larger an atomic nucleus gets, the more unstable it is. There are no stable atomic nuclei any larger than lead-208.

Re:Black holes are fiction (1)

ChowRiit (939581) | more than 4 years ago | (#30086294)

It's perfectly possible to pack matter into it's own Schwartzchild radius, that is the radius at which the escape velocity from the collective body is greater than the speed of light. Once the escape velocity is greater than the speed of light, nothing can escape and so a black-hole is by definition formed.

If you're really interested, you really need to study General Relativity to properly prove the plausibility of their existence.

Re:Black holes are fiction (1)

clone53421 (1310749) | more than 4 years ago | (#30086376)

The existence of a Schwartzchild radius assumes that gravity can ever be stronger than the repulsive forces within the nucleus. It cannot. Both increase simultaneously as you increase mass. Gravity's attractive force will never be stronger than the electrostatic forces that hold the particles apart.

Re:Black holes are fiction (1)

clone53421 (1310749) | more than 4 years ago | (#30086422)

To clarify that: because the attractive and repulsive forces scale simultaneously, and because the repulsive forces will always be much larger than the attractive forces, it is impossible to pack any amount of matter within its own Schwartzchild radius.

Well... (2, Funny)

hyperion2010 (1587241) | more than 4 years ago | (#30085990)

This sucks.

can we use a micro-black hole to power a stargate? (1)

Joe The Dragon (967727) | more than 4 years ago | (#30086028)

can we use a micro-black hole to power a stargate? as ZPM's are hard to find.

Re:can we use a micro-black hole to power a starga (3, Insightful)

ChowRiit (939581) | more than 4 years ago | (#30086424)

Black-holes are not a source of energy (excluding the monumentally tiny energy output via Hawking radiation), any energy gained harnessing black-holes would be from the accretion disk around them in which particles accelerating towards the black-hole emit radiation due to friction among themselves. However, you'd likely need a stellar-mass black-hole to get a realistic accretion disk going.

Anyway, ZPMs aren't hard to find, you just need Ancient-built replicator civilisations or time travel.

The problem is... (1, Insightful)

charliemopps11 (1606697) | more than 4 years ago | (#30086040)

The problem is, there is cause for real concern. Maybe not with the LHC but with science in general. 1. The universe is vast, and old. It's quite clear that, if life is as common as we think it is, the universe should be filled with ancient civilizations. 2. We have no evidence of any alien life... where are they? 3. We have a very rudimentary understanding of physics. 4. It may very well be that it is common for civilizations to evolve to the point at which we are at but then mistakenly destroy themselves through, what at first appear to be benign experiments. Not saying it will be a micro blackhole... or even the LHC. But we had better watch it. There might be a very simple reason that SETI hasn't found anything yet. They're all dead.

Re:The problem is... (1)

coolmoose25 (1057210) | more than 4 years ago | (#30086258)

The problem is, there is cause for real concern. Maybe not with the LHC but with science in general. 1. The universe is vast, and old. It's quite clear that, if life is as common as we think it is, the universe should be filled with ancient civilizations. 2. We have no evidence of any alien life... where are they? 3. We have a very rudimentary understanding of physics. 4. It may very well be that it is common for civilizations to evolve to the point at which we are at but then mistakenly destroy themselves through, what at first appear to be benign experiments. Not saying it will be a micro blackhole... or even the LHC. But we had better watch it. There might be a very simple reason that SETI hasn't found anything yet. They're all dead.

It is FAR more likely that if your theory is true, these ancient dead civilizations killed themselves off via the use of WMDs or through some other environmental catastrophe, whether caused by nature or their own stupidity. The likelihood that a scientist makes a mistake in an experiment and wipes out their whole civilization would be far down the list of possible causes of dead civilizations...

Re:The problem is... (1)

Anonymous Coward | more than 4 years ago | (#30086494)

Prove that they died due to a cause other than a science experiment.

Re:The problem is... (2, Insightful)

ChowRiit (939581) | more than 4 years ago | (#30086382)

To answer point 2, current evidence is that human radio signals will be distorted by the heliopause at the edge of the solar system such that they are undetectable from outside. Therefore, an incredibly strong and likely custom-built communication system would be needed to penetrate deep space and be detectable by aliens.

Secondly, while the Universe might be vast, we can only really stand a chance of picking up signals from within the Milky Way (and even then only fairly nearby, excluding stupendously powerful transmitters, perhaps), so the number of stars that could potentially signal us is vastly reduced.

Lastly, you have to limit that to only stars with habitable planets on which life has formed and evolved to a high level than ours, and then transmitted signals of sufficient power that reached Earth during the 50 or so years we've been listening.

Don't get me wrong, I think it's well worth using SETI etc to look but I don't think we should be shocked that we haven't found anything.

The author sounds so sure of himself.. (1)

buttle2000 (1041826) | more than 4 years ago | (#30086082)

..that he's got to be wrong.

Gotta Love the Author (0)

Anonymous Coward | more than 4 years ago | (#30086176)

TFA's author has surely done his black hole research. Quoting:

"What's more, I haven't seen any black holes float around my neighborhood recently."

I'm sure he meant some kind of gravitational lensing effect, or maybe some kind of high-energy radiation from an accretion disk or gas jet.

MBH = mega black hole? (2, Interesting)

MacAnkka (1172589) | more than 4 years ago | (#30086188)

Am I the only one who reads MBH as mega black hole, not micro black hole? It's confusing. If the prefix is micro, it would make sense to use a letter that actually means micro, instead of a letter that represents mega.

Re:MBH = mega black hole? (1)

ChowRiit (939581) | more than 4 years ago | (#30086254)

It is somewhat confusing, I agree, as the greek letter "mu" normally represents micro, and "SMBH" is the normal acronym for Super Massive Black Hole (black holes at the centres of galaxies that weigh millions of times the mass of the sun).

Geocide (1)

Lord Bitman (95493) | more than 4 years ago | (#30086358)

Sam Hughes will be so disappointed

All the speculation is driving me crazy. (1)

Tibor the Hun (143056) | more than 4 years ago | (#30086408)

Come on guys, this is not rocket science!

John Titor (1)

WormholeFiend (674934) | more than 4 years ago | (#30086430)

used a time machine made with mini black holes, in case you guys have forgotten..

Get your crowbars ready. (2, Funny)

RealErmine (621439) | more than 4 years ago | (#30086592)

I'm more worried about the possibility of a resonance cascade.
Load More Comments
Slashdot Login

Need an Account?

Forgot your password?