Probing Question: Could the Large Hadron Collider swallow the Earth?

Jan 21, 2009 By Solmaz Barazesh
Probing Question: Could the Large Hadron Collider swallow the Earth?
Large Hadron Collider. Photo: CERN

Nestled 570 feet beneath the Alps on the Swiss-French border is the world’s largest physics experiment — the Large Hadron Collider (LHC). Constructed for $8.8 billion by the European Organization for Nuclear Research (CERN) in Geneva, Switzerland in collaboration with hundreds of universities and labs worldwide, the LHC was built to test various key predictions of high-energy physics by smashing proton beams together at high speeds.

Critics contend that the awesome power of the LHC — which will accelerate particles at up to 99.99 percent of the speed of light and create temperatures in the trillions of degrees — has the potential to create a black hole that could consume the Earth. These fears have resulted in a lawsuit filed at the European Convention of Human Rights with motions against the 20 countries, including the U.S., which have funded the project.

Should we be worried?

“Absolutely not,” is the verdict from Stéphane Coutu, Penn State professor of physics. “The world is constantly bombarded by energetic cosmic rays from the depths of space, some of them inducing particle collisions thousands of times more powerful than those that will be produced by the LHC,” explained Coutu. “If these collisions could create black holes, it would have happened by now.”

Fears about black holes are exacerbated by media hype about the supercollider, with headlines labeling it a “Doomsday Device” and “Big Bang Machine.” What really is the LHC, and how can smashing particles together tell us anything new about the universe?

The most powerful particle accelerator ever built, “the LHC consists of an underground tunnel measuring over 17 miles in circumference,” described Coutu. Opposing beams of protons will be blasted through the tunnel, causing them to collide and break into smaller fragments; particle detectors positioned along the tunnel will analyze the fallout of the collisions.

Noted Coutu, “The end product of the particle collisions could provide new insight into how particles interact—ultimately, this could explain the outcome of particle processes shortly after the Big Bang from which the universe derives.”

Another possibility is that “we could observe the Higgs boson as a by-product of the particle collisions,” Coutu suggested. The mysterious Higgs boson is a hypothetical particle predicted to exist by the Standard Model of particle physics, but never experimentally isolated. Thought to provide mass to other particles, the Higgs boson — sometimes dubbed the “God particle” — could hold the key to understanding why matter behaves the way it does — meaning that verification of its existence would be a breakthrough in particle physics.

“In addition to this experimental data, the LHC could yield practical improvements to our everyday lives,” Coutu added, pointing out that the World Wide Web was developed by the same organization that built the LHC for the purpose of exchanging large amounts of scientific information. “New computing methods to process and analyze these extremely large data sets will have to be developed,” Coutu said. “These advances may percolate down to applications outside the laboratory,” he concluded.

But the physicists chomping at the bit to get their hands on these vast amounts of new data will have to wait just a little longer. The LHC was slated to commence smashing in September 2008, but was turned on for just nine days before technical difficulties halted work and pushed back the start of regular operations to Spring 2009. The cause of the delay was faulty superconducting magnets (traced back to defective soldering on a connection) which leaked six tons of ultra-cold liquid helium into the accelerator tunnels. “The accelerator and associated particle detectors push the envelope of the technological state-of-the-art, and the sheer complexity of the endeavor leads to unavoidable delays,” commented Coutu.

The LHC has some lofty goals — to answer questions about our universe which humans have puzzled over for centuries — and the sheer scale and scope of the project has captured the imagination of people everywhere. As Coutu concluded, “It is hard to imagine anything more fundamental as an example of human pursuit of pure knowledge.”

Source: By Solmaz Barazesh, Research Penn State

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earls
3.7 / 5 (6) Jan 21, 2009
Hey, I hope we get to read the same article again next month!
OregonWind
4 / 5 (3) Jan 21, 2009
Well, that would happen so fast that would not make much difference, isn't? Although there is actually an infinitesimal probability that something catastrophic would happen I would go for the experiment and let the doomsday people cultivate their fears. We are not that 'lucky'!
Ant
2.7 / 5 (7) Jan 21, 2009
what a waste of time and money.
javjav
4.2 / 5 (5) Jan 21, 2009
The Hiroshima nuclear explosion (and many, many others) created much more energetic particle collisions. As a result, we have a great margin to experiment in particle colliders. No need to worry until we go beyond the nuclear weapons record.
It seems that we are going to destroy the planet anyway, but it seems to me that Hadrons are not going to do the job.

docknowledge
1 / 5 (3) Jan 21, 2009
As before and always with the collider, the problem is that if the experts happen to be wrong, their mistake can't be fixed by an apology.

What they should be is honest enough to admit that they are willing to take chances. Not just chances for themselves but for others. I.e., that they don't have a problem with taking away the free rights of other people. In other contexts such people are called criminals. And that's what they are in this context. Criminals.
barkster
3.7 / 5 (3) Jan 21, 2009
Hey, I hope we get to read the same article again next month!
I do, too! I want to hear them counter-punch the "earth-swallowing black-hole" nuts every day and in every possible way, until those nuts are so humiliated over their nutty-ness that they wither away into their little hypochondriac worlds and leave sound, measured, scientific progress alone.

OMG... THE WHEEL!! That could lead humanity to destroy itself by driving drunk!!
theophys
3.3 / 5 (4) Jan 21, 2009
Correct me if I'm wrong, but don't we have generaly the same amount of energy in particle collisions in the upper atmosphere? Are we dead? I'm pretty sure the sun has much more energetic reactions. Has a black hole been created inside the sun?
Frankly, at this point, only complete morons and people who enjoy being frightened have any reason to be fearful.
SkiveHard
2.3 / 5 (3) Jan 21, 2009
@barkster: I've got no problem with people who heard about the LHC and got a little worried. Thing is, if you think something is going to destroy the world surely the first thing you'd do is go and learn a bit about it, right? I'll never understand people who's first impuse is to compare CERN to the third reich without bothering to learn what they're talking about. I know, I know, welcome to the internets.

@docknowledge: Can you prove that the world won't cease to exist the next time I clap my hands? So when I clap my hands, I'm putting the world at risk, right? Thing is, the empirical evidence for a proton-proton collision at LHC energies being safe is better than the evidence for hand clapping. So do you really think the term "risk" applies to the LHC?

@javjav: Nope, the particle collisions at the LHC will be many orders of magnitude more energetic (massively fewer particles, though). If you want collisions that make the LHC look feeble, check out cosmic rays (somewhere above your head, right now).
barkster
3.7 / 5 (3) Jan 22, 2009
SkiveHard, I also have no grief with people who get a little worried. You are right to point that out.

Putting the reading public's knowledge of the subject technology aside... What I do have a problem with are those create/incite/inflame these little worries through repititous fearmongering through a complacent (if not complicit) media. That's why I am only to happy to see equally emphatic responses such as this one.

BRAVO, PHYSORG! (now, if you would do the same for "global warming".)
Noumenon
4.7 / 5 (47) Jan 22, 2009
Lol, yes GW is pure bs.

The cosmic ray point just sounds like a 'dumb guy' argument. It gives the impression that it's not known fundamentally why a BH won't engulf everything, thus relying on some other phenomenon as evidence, glossing over the differences in the two cases; non-scientific, and of a similar quality of argument as the fear rationality. There was a technical argument done disproving BH (?), that these articles should at least reference.
Noumenon
4.7 / 5 (47) Jan 22, 2009
Also, it's not like a couple of ding-bats who run a bakery over the LHC are the ones inciting fear, ... other Phd's are involved to the extent of not being 99.99% satisfied with arguments against the possibiity of BH. It's hard to believe that 98% of physicists are wrong, but I wouldn't call the rest 'morons' or 'nuts', especially when the entire point of the LHC is to GAIN knowledge of nature,..

(Oh, and don't bother pointing out how my GW comment is hypercritical :) )
magpies
2 / 5 (4) Jan 22, 2009
One way or some other it will fail. And humanity will pay the price :)
Ant
2 / 5 (4) Jan 22, 2009
If you proponents of the LHC and its safety are so damn sure nothing could go wrong then perhaps you would like to explain why a simple mechanical fault is presenting so much of a problem and where the soot in the beam pipes came from. OK suppose it does spply answers, so what? who gains? a few physics geeks wanting to show off. But guess what, nobody cares. All most people care about is their safety and their own and relatives well being. Why should any risk to others be considered acceptable especcialy when they couldnt even put it together properly.
SaneScienceOrg
1.6 / 5 (5) Jan 22, 2009
Man's technology has exceeded his grasp. - 'The World is not Enough'
("I'm slightly irritated, because this non-story is symptomatic of a larger mistrust in science, particularly in the US, which includes things like intelligent design. Anyone who thinks the LHC will destroy the world is a twat." Arrogant, deluded douchebag and CERN spokesmodel, Brian Cox.)
(September 19, 2008 - 'LHC loses liquid helium' - PhysicsWorld.com: "The Large Hadron Collider (LHC) has lost up to a tonne of liquid helium after some of its superconducting magnets inadvertently heated up this morning, physicsworld.com has learnt. A log entry written by the current LHC co-ordinator at 11:27 am CET (10:27 am BST) states that there has been a "massive quench" in sector 3%u20134. Quenches occur when superfluid helium in the magnets rises above its operating temperature of 1.9 K, and can be caused, for example, when a proton beam veers off course.")
(September 24, 2008 - 'LHC on hold until spring of 2009' - PhysicsWorld.com: "The magnet failure last week at the Large Hadron Collider (LHC) means that the accelerator will not be up and running again until early spring of 2009, say officials at CERN. To keep the project on schedule, the team running the accelerator near Geneva have decided to skip a planned test run at an intermediate energy and re-start the LHC in 2009 at the full beam energy of 7 TeV.") And begin creating Black Holes.
Zealous, jealous, Nobel Prize hungry Physicists are racing each other and stopping at nothing to try to find the supposed 'Higgs Boson'(aka God) Particle, among others, and are risking nothing less than the annihilation of the Earth and all Life in endless experiments hoping to prove a theory when urgent tangible problems face the planet. The European Organization for Nuclear Research(CERN) Large Hadron Collider(LHC) is the world's most powerful atom smasher that will soon be firing groups of billions of heavy subatomic particles at each other at nearly the speed of light to create Miniature Big Bangs producing Micro Black Holes, Strangelets, AntiMatter and other potentially cataclysmic phenomena as described below.
Particle physicists have run out of ideas and are at a dead end forcing them to take reckless chances with more and more powerful and costly machines to create new and never-seen-before, unstable and unknown matter while Astrophysicists, on the other hand, are advancing science and knowledge on a daily basis making new discoveries in these same areas by observing the universe, not experimenting with it and with your life. Einstein used Astronomy to prove his landmark general theory of relativity that, ironically, decribes, among other things, the Black Holes which the LHC is designed to produce at the hoped for rate of one per second.
The LHC is a dangerous gamble as CERN physicist Alvaro De Rújula in the BBC LHC documentary, 'The Six Billion Dollar Experiment', incredibly admits quote, "Will we find the Higgs particle at the LHC? That, of course, is the question. And the answer is, science is what we do when we don't know what we're doing." And CERN spokesmodel Brian Cox follows with this stunning quote, "the LHC is certainly, by far, the biggest jump into the unknown."
The CERN-LHC website Mainpage itself states: "There are many theories as to what will result from these collisions,..." Again, this is because they truly don't know what's going to happen. They are experimenting with forces they don't understand to obtain results they can't comprehend. If you think like most people do that 'They must know what they're doing' you could not be more wrong. Some people think similarly about medical Dr.s but consider this by way of comparison and example from JAMA: "A recent Institute of Medicine report quoted rates estimating that medical errors kill between 44,000 and 98,000 people a year in US hospitals." The second part of the CERN quote reads "...but what's for sure is that a brave new world of physics will emerge from the new accelerator,..." A molecularly changed or Black Hole consumed Lifeless World? The end of the quote reads "...as knowledge in particle physics goes on to describe the workings of the Universe." These experiments to date have so far produced infinitely more questions than answers but there isn't a particle physicist alive who wouldn't gladly trade his life to glimpse the "God particle", and sacrifice the rest of us with him. Reason and common sense will tell you that the risks far outweigh any potential(as CERN physicists themselves say) benefits.
This quote from National Geographic, "The hunt for the God particle", exactly sums this "science" up: "If all goes right, matter will be transformed by the violent collisions into wads of energy, which will in turn condense back into various intriguing types of particles, some of them never seen before. That's the essence of experimental particle physics: "You smash stuff together and see what other stuff comes out." Read about the "other stuff" below;
http://www.SaneScience.org
http://www.risk-e...non6.htm
http://www.LHCFacts.org/
http://www.LHCDefense.org/
http://www.LHCConcerns.com/
Popular Mechanics - "World's Biggest Science Project Aims to Unlock 'God Particle'" - http://www.popula...8.html"

docknowledge
3 / 5 (4) Jan 22, 2009
SkiveHard (writing to me): "Can you prove that the world won't cease to exist the next time I clap my hands?"

Hi, I actually appreciate you writing this. I took statistics in college, and it was a central part of my job for some years. Your comment actually illustrates why the "collider decision" is so extremely dangerous: the people involved in evaluating the risk are professional physicists, not statisticians, and probably never took a class, read a book, or attended a lecture on risk assessment. Humans are not very good at "common sense" assessment of risk. They often wildly over- or under-estimate. So where does that leave us? With a lot of predictions of "risk" by people who have no business making any statement whatsoever. In lieu of knowing what the unknown risk is, the prudent thing is not to take the risk. And that of course, is an argument that many scientists find deeply offensive, because to them, it's an article of faith that things "must" be explored.
SkiveHard
1 / 5 (2) Jan 22, 2009
@Noumenon: Well theres two ways of approaching the problem - one is from theory (hawking radiation, arguments from thermodynamics) the other is by starting from the hypothesis "proton-proton collisions at LHC energies produce stable black holes" and seeing whether the consequences are consistent with observation. Personally, I find the second approach more compelling.

If at least some of the back holes are charged (which, well, they would be) then the hypothesis is not consistant with the continued existance of the earth. If you manage to avoid charged black holes somehow, then the hypothesis is not consistant with the existance of white dwarfs (and they are one of the most common objects in the sky).

The cosmic ray analysis isn't the simple minded thing you might think it is - it takes account of the differences between LHC collisions and cosmic ray collisions. Search it out if you're interested.
SkiveHard
1 / 5 (1) Jan 22, 2009
@Noumenon pt:2
Since you bring up the scientific credibility of the people in question - I checked them out, and so far I see a professor in bio-chemistry, a guy who worked with cosmic rays a long time ago and who now works in nuclear medicine and a few people whos scientific credentials seem to be self awarded. None of this would matter if they had good arguments... but they don't.

Theres also a guy called Plaga, who is a genuine phyicist. He's saying something completely different to all the others and is having nothing to do with them as far as I can see. He also seems to have got his sums wrong.
SkiveHard
not rated yet Jan 22, 2009
@Ant Who said nothing could go wrong? I just said that the LHC can't produce planet swallowing black holes. Theres nothing in the laws of physics to stop some guy f%^&ing up a weld.

@SaneScienceOrg TLDNR
SkiveHard
not rated yet Jan 22, 2009
@docknowledge: Oddly enough scientists have to know stats too - you can't really do science without them. A way of putting what I said into rigorous language would be:

From the experimental data, the upper limit of the probability of a proton-proton collision casuing a back hole that swallows the planet is lower than the upper limit of the probability of a hand clap doing the same, for any given confidence level.

Proton-proton collisions at LHC energies are massively more common than hand claps. The reason that clapping your hands is seen as safe and proton-proton collisions are seen as suspect is surely because clapping your hands is familiar to us in every day life. If you've worked in risk assessment then you must know that mistaking "familiar" for "frequent" is exaclty the kind of error that throws off "common sense" evaluation of risk.

If you think the LHC is not worth the risk, why do you think capping your hands is?
denijane
not rated yet Jan 22, 2009
Again?! Come on, didn't we already decide LHC isn't going to eat the Earth! I didn't even read it.
VinceCataldi
1 / 5 (1) Jan 22, 2009
"awesome power" - Good Gulp!
barkster
not rated yet Jan 22, 2009
@Ant Who said nothing could go wrong? I just said that the LHC can't produce planet swallowing black holes. Theres nothing in the laws of physics to stop some guy f%^&ing up a weld.
Agreed. That would be like saying that because your auto mechanic didn't properly tighten a radiator hose, you now have evidence the car is dangerous because the internal combustion engine could theoretically go supercritical. Jeez...
Alizee
Jan 22, 2009
This comment has been removed by a moderator.
Ant
1 / 5 (1) Jan 22, 2009
Barkster etal:
lets reflect on the putting together of the solid rocket boosters to the shuttle. Didnt 5 people die because of that.
your analogy is as daft as saying that an aircraft can be thrown together in the hope that nothing goes wrong. pity it may fall out of the sky. This machine has the potential for disaster, mistakes can not be made and we dont know the possible outcomes of such disasters. The history of this planet is littered with problems created by humans. can we really take the chance?
Alexa
1 / 5 (1) Jan 23, 2009
On the Possibility of Catastrophic Black Hole Growth in the Warped Brane-World Scenario at the LHC

http://arxiv.org/abs/0901.2948

Based on this analysis, we argue against the possibility of catastrophic black hole growth at the LHC.

Good night. Did you ever realize, what the contemporary science is?
theophys
not rated yet Jan 23, 2009
This machine has the potential for disaster, mistakes can not be made and we dont know the possible outcomes of such disasters. The history of this planet is littered with problems created by humans. can we really take the chance?

At worst, something goes wrong, none of the safety precautions work, and there's a large explosion. And by large, I mean bigger than anything I can do in my back yard, but not bigger than some of the bombs we've made. Seriously, unless you happen to be working on site or maybe really close to the site, you'll be fine. Note, that's if everything goes wrong and none of the trained problem solvers do anything more than scratch their heads and fling feces. We are more likely to die in a nuclear holocaust than we are due to anything coming from the LHC. Why not go be concerned with something a little more lethal? Like peanut butter.
ubavontuba
1 / 5 (1) Jan 24, 2009
From the article:
%u201C'Absolutely not,%u201D is the verdict from Stéphane Coutu, Penn State professor of physics. %u201CThe world is constantly bombarded by energetic cosmic rays from the depths of space, some of them inducing particle collisions thousands of times more powerful than those that will be produced by the LHC,%u201D explained Coutu. %u201CIf these collisions could create black holes, it would have happened by now.'%u201D

Pofessor Stéphane Coutu is apparently an ignoramous. The 2008 LSAG (LHC safety committee) clearly falsified the validity of this argument ...as follows:

From the CERN Giddings and Mangano paper:
"In view of the value for Earth do(E) ~ 3 × 10^11 cm, these mechanisms cannot efficiently
slow down neutral CR (cosmic ray)-produced black holes in Earth, or in other bodies such as planets
and ordinary stars... For... typical black holes produced at the LHC... however, there
is small but finite probability for them to be produced with velocities small enough to
become gravitationally bound to the Earth and, in the hypothetical case of stability, to
begin accreting."

There's more on this in the two other (less formal) reports too.

SkiveHard
not rated yet Jan 24, 2009
@Ant: I get the feeling that you see the LHC control room as having two buttons - a big green one labelled "find higgs" and a big red one labelled "destroy planet". You've really got to hope they've hired a good electrician.

Human fallibility is undeniable, but can I give you an alternative analogy? It is possible that every single incidence of the "dropping stuff" experiment has been messed up, and the real truth is that when you let go of things they fall upward. Human beings make mistakes, so its a possibility you can't rule out. Being wrong about it would have pretty dire consequences for us all. But does it stop you leaving the house?
SkiveHard
not rated yet Jan 24, 2009
@ubavontuba To re-quote the paper you quote:

"these mechanisms cannot efficiently
slow down neutral CR (cosmic ray)-produced black holes"

The important word there is "neutral". You're going to get charged black holes too (they take on the charge of whatever they're made from). And charged particles get stopped by matter rather effectivey. You can verfiy this by accelerating a source of charged particles (say, your head) at a suitable target (for example, a wall). In the interest of safety I suggest you start at low energy and work up until you have achieved satisfactory results.

Anyway, a charged black hole from a cosmic ray is going to loose energy, slow down, stop in the earth then get to devouring. That doesn't seem to have happened, which means that either they don't happen or they decay too fast. Either way, it means the LHC won't kill us all.

The beauty of the G&M approach is that it requires black holes to have absolutely no characteristics other than their tendacy to eat stuff. In that sense its simpler - but you've seen the paper, its a monster. If all you've got room for is a two sentance quote, then you're probably better off going for the less awesome but easier to explain earth based version.
ubavontuba
1 / 5 (2) Jan 24, 2009
@ubavontuba To re-quote the paper you quote:

"these mechanisms cannot efficiently
slow down neutral CR (cosmic ray)-produced black holes"

The important word there is "neutral". You're going to get charged black holes too (they take on the charge of whatever they're made from).

This is a supposition. It's not proven.

Besides, it does nothing to support Stéphane Coutu's contentions.

Anyway, a charged black hole from a cosmic ray is going to loose energy, slow down, stop in the earth then get to devouring. That doesn't seem to have happened, which means that either they don't happen or they decay too fast.

I vote for the former (black holes have no charge).

The beauty of the G&M approach is that it requires black holes to have absolutely no characteristics other than their tendacy to eat stuff. In that sense its simpler - but you've seen the paper, its a monster. If all you've got room for is a two sentance quote, then you're probably better off going for the less awesome but easier to explain earth based version.


Okay. Here's some excerpts from the 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."

As can plainly be seen, the LSAG papaers do not support Stéphane Coutu's contentions.
SkiveHard
not rated yet Jan 24, 2009
@ubavontuba: The existance of charged black holes is no more a supposition than the existance of black holes in general - if the thing you're talking about doesn't have the capacity to have a charge, then its not a black hole but something you've invented.

Now there is a way for charged back holes to radiate away their charge - basicly, hawking radiation. But the whole existance of stable black holes is based on the idea that Hawking radiation somehow doesn't happen.

You're misreading the summary report - "Stable black holes could be either electrically charged or neutral." doesn't mean that they're all either charged _or_ neutral, it means that you will get both charged _and_ neutral black holes.

Its important to understand that neither the G&M paper nor the summary report are arguing that Hawking radiation doesn't work or that charged back holes can't exist - they argue that it _doesn't_matter_. The point is that discussions like the one we're having are redundant, because even if you proposed a black-hole-like beastie that did nothing but eat planets (and was unlike a black hole in every other way) the observation of white dwarfs rules out the possibility of it being created at LHC energies.
Alexa
1 / 5 (1) Jan 24, 2009
...the observation of white dwarfs rules out the possibility of it being created at LHC energies..
Why? Why the observation of Santa Claus doesn't work by such way?
...whole existance of stable black holes is based on the idea that Hawking radiation somehow doesn't happen..
Hawking radiation is just a unconfirmed yet theory - by the same way, like others. The fact, it remains unconfirmed for longer time, then other concurrent theories doesn't make it more valid in my eyes - on the contrary.

But the black hole is an extreme example of symmetry. Here are a more probable scenarios - the formation of less dense objects, but in larger number and therefore even worse effects.

For example the droplets of dense neutron fluid. Free neutrons are be stable for minutes. How they would be stable in condensed state? Nobody knows.

Oh, wait - how is it possible? Because nobody really cares about it - people wants their journal articles and scientists wants their money and Nobel prices.
ubavontuba
1 / 5 (1) Jan 25, 2009
@ubavontuba: The existance of charged black holes is no more a supposition than the existance of black holes in general - if the thing you're talking about doesn't have the capacity to have a charge, then its not a black hole but something you've invented.

That's not true. Charged black holes are (supposedly) predicted in quantum field theory, which melds poorly with gravity.

Now there is a way for charged back holes to radiate away their charge - basicly, hawking radiation. But the whole existance of stable black holes is based on the idea that Hawking radiation somehow doesn't happen.

Which is a perfectly reasonable concept.

You're misreading the summary report - "Stable black holes could be either electrically charged or neutral." doesn't mean that they're all either charged _or_ neutral, it means that you will get both charged _and_ neutral black holes.

Wrong. You need to read the full context. What they're saying is it isn't proven either way.

Its important to understand that neither the G&M paper nor the summary report are arguing that Hawking radiation doesn't work or that charged back holes can't exist - they argue that it _doesn't_matter_. The point is that discussions like the one we're having are redundant, because even if you proposed a black-hole-like beastie that did nothing but eat planets (and was unlike a black hole in every other way) the observation of white dwarfs rules out the possibility of it being created at LHC energies.

No, it doesn't. This is also clearly outlined in the papers. I suggest you read them.
ubavontuba
1 / 5 (1) Jan 25, 2009
From the G & M paper:

"As shown in table 1, the column densities required to stop the heaviest black holes for D > 8 exceed the stopping power of even the most massive white dwarfs, and therefore we shall only state empirical constraints on such scenarios when discussing the neutron stars case."

So, even they suggest that stopping in white dwarfs might not be possible. They go on to suggest they're likely to be protected by magnetic fields too.
MichaelJM
not rated yet Jan 25, 2009
"Fears about black holes are exacerbated by media hype about the supercollider"
-Media hype like this?

I had been reading articles about the LHC for years and years, and I was so excited that it was finally up and running, because that meant people could start writing about new stuff in relation to it. Then it stopped working. If that means more articles like this, I can't wait for them to fix it.
theophys
not rated yet Jan 25, 2009
I had been reading articles about the LHC for years and years, and I was so excited that it was finally up and running, because that meant people could start writing about new stuff in relation to it. Then it stopped working. If that means more articles like this, I can't wait for them to fix it.

I heard it was already fixed, but they're waiting until the summer to fire it up again. Something about particle physisists needing to hybernate.
Now there is a way for charged back holes to radiate away their charge - basicly, hawking radiation. But the whole existance of stable black holes is based on the idea that Hawking radiation somehow doesn't happen.

Which is a perfectly reasonable concept.

But why would you just assume there's no Hawking radiation? What evidenseor counter theory can you provide? Do you discard it because it prohibits LHC-related fear mongering?
ubavontuba
1 / 5 (1) Jan 25, 2009
But why would you just assume there's no Hawking radiation? What evidenseor counter theory can you provide?
Well for one, the GR solution for a black hole is that it's truly black. It does not radiate.

For another, the Hawking hypothesis fails to consider the gravitational potential/kinetic energy of the infalling particle (the one that's supposed to be subtracting energy from the black hole).

For another, this would be a really cool solution for dark matter, and perhaps dark energy too.

For another, if black holes were created by cosmic rays, and they subsequently evaporated, we might reasonably expect to see this in our particle detectors.

Do you discard it because it prohibits LHC-related fear mongering?
What makes you think it's safe?
barkster
not rated yet Jan 26, 2009
Ant,

The size and character of the explosion in the shuttle disaster (God rest their brave and risk-taking souls) was measurable and preventable with reasonable safety/quality measures (hindsight notwithstanding... no one ever said it was 'risk-free'). The size and character of the explosion an internal combustion enghine will make if "detonated" is also measured and preventable with reasonable safety/quality control... otherwise, NASA and the auto industry would be deader than door nails.

LHC fearmongerer's apparently presume to know/believe of extraordinary excessive potential power in these devices that they simply can't account for.

My analogy stands... a mechanical failure and the resulting damage in a sub-system is not proof that the super-system is a ticking-bomb of uncalculated destructive power, or that the design is short on regard for safety. Ergo, if your radiator hose springs a leak because your mechanic screwed up, your car engine can't explode with nuclear force, since it was never designed to achieve that power in the first place. If another shuttle explodes (heaven forbid), it won't detonate with any more force than the last one.

LHC will produce incredibly powerful collision, but it won't create earth-swallowing BHs... on purpose or by accident.
SkiveHard
not rated yet Jan 26, 2009
@ubavontuba:

"Charged black holes are (supposedly) predicted in quantum field theory, which melds poorly with gravity."

Nope. Charged black holes are a prediction of classic GR. They were first described in 1916. Check out the Reissner-Nordstrom metric. (String theory, etc, predict loads of other kinds of "hair" on top of that, but charge is much more fundamental).

"Which is a perfectly reasonable concept."
You might want to reread my comment - either you have hawking radiation and no stable black holes or no hawking radiation and no neutralization (so you have charged black holes).

"You need to read the full context."

The full context is that both charged an neutral black holes would be produced in proton-proton collisions (if any black holes were produced at all). If you see an indication to the contrary, please quote it.

"D > 8 exceed the stopping power of even the most massive white dwarfs"

Black holes in the D>=8 scenario are extremely un-grabby (to use a scientific term). This means that they fall outside the range that can be stopped by white dwarfs. But _exactly_that_quality_ means that they accrete matter so slowly that they would take much longer to grow than the sun has left to burn (sections 4.2 and 4.3). Which I'm guessing nobody minds. The study excludes _dangerous_ back holes (apologies if I left off "dangerous" in an earier post).

"They go on to suggest they're likely to be protected by magnetic fields too."

They cover magnetic screening in section 6.1. Its included in their calculations.
theophys
not rated yet Jan 27, 2009
For another, the Hawking hypothesis fails to consider the gravitational potential/kinetic energy of the infalling particle (the one that's supposed to be subtracting energy from the black hole

That's not true. You forget the energy carried away by the particle that escapes.
For another, if black holes were created by cosmic rays, and they subsequently evaporated, we might reasonably expect to see this in our particle detectors.

Name one particle detector that could detect miniature black holes in the atmosphere. It would have to be extremely sensitive, floating around in the atmosphere, and large enough to cover a significant area for maximum chances at seeing the bh's.


Do you discard it because it prohibits LHC-related fear mongering?

What makes you think it's safe?

Two reasons, 1)hawking radiation, and 2)hawking radiation. The debate raged long before I came to the physics scene and it is pretty well settled in my mind. The LHC is not going to destroy the world.

Besides, if I am wrong and it turns out that modern physics was all wrong, who cares? If the world is sucked into a black hole, there won't be enough time for regret and blame. It would be a matter of minutes before the black hole took in the entire world. If you happen to be religious and beleive that you will have an after life in which to point fingers, I would think that you would be more excited about eternal paradise than you would be outraged over a quick and nearly painless death.
ubavontuba
1 / 5 (1) Jan 28, 2009
Nope. Charged black holes are a prediction of classic GR. They were first described in 1916. Check out the Reissner-Nordstrom metric. (String theory, etc, predict loads of other kinds of "hair" on top of that, but charge is much more fundamental).
I don%u2019t strictly buy this for reasons that are too complex to explain here, but even if stable micro black holes did exhibit charge, they%u2019d quickly neutralize themselves by absorbing oppositely charged particles.

It%u2019s irrelevant anyway. Charged micro black holes are essentially ruled out. If charged micro black holes were created by cosmic ray collisions, they%u2019d interact with ordinary matter and we would%u2019ve long since been destroyed, or we%u2019d detect their Hawking radiation.

From the summary report:

%u201CStable black holes could be either electrically charged or neutral. If they had electric charge, they would interact with ordinary matter and be stopped while traversing the Earth, whether produced by cosmic rays or the LHC. The fact that the Earth is still here rules out the possibility that cosmic rays or the LHC could produce dangerous charged microscopic black holes.%u201D

You might want to reread my comment - either you have hawking radiation and no stable black holes or no hawking radiation and no neutralization (so you have charged black holes).
Like I and the summary report said, charged micro black holes are essentially ruled out. Even so, why do you think a stable, charged micro black hole can%u2019t neutralize itself? This concept is explored in the G&M paper:

%u201CWe have no concrete example of a consistent microphysics such that black holes neutralize via Schwinger discharge but don%u2019t Hawking radiate, but our present state of knowledge of quantum black hole processes doesn%u2019t strictly rule out such a possibility.%u201D

The full context is that both charged an neutral black holes would be produced in proton-proton collisions (if any black holes were produced at all). If you see an indication to the contrary, please quote it.
I%u2019ve seen speculation on the validity (or not) of the Reissner-Nordstrom metric, but I digress%u2026

They cover magnetic screening in section 6.1. Its included in their calculations.

Oh brother. They essentially say the white dwarfs would have to have unusually weak magnetic fields for it to work at all.

ubavontuba
1.8 / 5 (5) Jan 28, 2009
@theophys:

That's not true. You forget the energy carried away by the particle that escapes.
Apparently, you misunderstood my statement.

Name one particle detector that could detect miniature black holes in the atmosphere. It would have to be extremely sensitive, floating around in the atmosphere, and large enough to cover a significant area for maximum chances at seeing the bh's.
http://www.physorg.com/news152284387.html

Two reasons, 1)hawking radiation, and 2)hawking radiation. The debate raged long before I came to the physics scene and it is pretty well settled in my mind. The LHC is not going to destroy the world.
I'm glad for you that you feel so comfortable with it.

Besides, if I am wrong and it turns out that modern physics was all wrong, who cares?
I do!

If the world is sucked into a black hole, there won't be enough time for regret and blame. It would be a matter of minutes before the black hole took in the entire world.
What makes you think this?

If you happen to be religious and beleive that you will have an after life in which to point fingers, I would think that you would be more excited about eternal paradise than you would be outraged over a quick and nearly painless death.

I'd much rather the earth and all of it's bountiful life, continue indefinitely.

mvg
not rated yet Jan 28, 2009
"koros, ubris, ate"

It is a very old formula, but still relevant, since it reveals a basic (and universal) flaw in human nature=

"excessive pride, leads to outrageous behaviour, which in turn leads to destruction"
SkiveHard
not rated yet Jan 28, 2009
@ubavontuba:

"I don't strictly buy this for reasons that are too complex to explain here, but even if stable micro black holes did exhibit charge, they'd quickly neutralize themselves by absorbing oppositely charged particles."

You'd think so, but no - remember, for mBHs to exist at all, we're talking about a situation where its gravitational attraction overwhelms all else (at short range). It preferentially absorbs neutrons and protons over electrons (because they have greater mass) so the charge actually grows with time.

"Charged micro black holes are essentially ruled out."

Exactly! And what I'm arguing here is that ruling out charged black holes (obervationally) allows you to rule out neutral black holes too.

"We have no concrete example of a consistent microphysics such that black holes neutralize via Schwinger discharge but don't Hawking radiate, but our present state of knowledge of quantum black hole processes doesn't strictly rule out such a possibility."

But you understand their implication that having the Schwinger mechanism without Hawking radiation involves making up some rather arbitrary new physics, right? This is on top of the extremely arbitrary new physics you have to make up to stop Hawking radiation happening.

"I've seen speculation on the validity (or not) of the Reissner-Nordstrom metric, but I digress"

I'm intriuged, can you post a link?

"Oh brother. They essentially say the white dwarfs would have to have unusually weak magnetic fields for it to work at all. "

Well, no, what they do is define an ideal sample of white dwarfs at the lower end of magnetic field strength, purely because they make the calculations easier. After all, a charged particle coming directly down at a magnetic pole doesn't experience any deflection at all, no matter how strong the field.
theophys
not rated yet Jan 29, 2009
You'd think so, but no - remember, for mBHs to exist at all, we're talking about a situation where its gravitational attraction overwhelms all else (at short range). It preferentially absorbs neutrons and protons over electrons (because they have greater mass) so the charge actually grows with time.

I'm totaly on bored with present black hole physics except for the charge thing. I don't understand exactly how the charge is kept after the particles are crushed to a point of infinite density. No doubts, but that's just one of those things that nobody was ever able to explain to me.

If the world is sucked into a black hole, there won't be enough time for regret and blame. It would be a matter of minutes before the black hole took in the entire world.

What makes you think this?

It's an exponential growth. the more matter and energy the bh pulls in, the stronger its force and the faster matter starts coming in, which in turn makes it stronger and so on so forth. That of course is assuming that there is no charge or spin to make the whole action more violent. You would have about enough time to say, "Those darn kids!" before the tidal forces rip you apart and your remains are crushed into a singularity. That is of course assuming that there's no Hawking radiation to stop the whole thing within microseconds of the creation of the thing.
Name one particle detector that could detect miniature black holes in the atmosphere. It would have to be extremely sensitive, floating around in the atmosphere, and large enough to cover a significant area for maximum chances at seeing the bh's.

http://www.physor...387.html

I would scoff, but that's difficult to do through a keyboard. A WIMP detector in a mine shaft doesn't stand a chance of detecting anything in the atmosphere. They're designed to dectect things that passthrough our atmosphere with little to no interations with other particles, and they only have a small chance of success with that.
ubavontuba
1 / 5 (1) Jan 31, 2009
@SkiveHard:

You'd think so, but no - remember, for mBHs to exist at all, we're talking about a situation where its gravitational attraction overwhelms all else (at short range). It preferentially absorbs neutrons and protons over electrons (because they have greater mass) so the charge actually grows with time.
Oh bro-ther! That's like saying big rocks fall faster than small rocks. Worse, you're ignoring the electromagnetic attraction.

Exactly! And what I'm arguing here is that ruling out charged black holes (obervationally) allows you to rule out neutral black holes too.
Sorry, I just don't buy this. I feel the Reissner-Nordstrom metric is fundamentally flawed. I think all black holes are likely neutral.

But you understand their implication that having the Schwinger mechanism without Hawking radiation involves making up some rather arbitrary new physics, right? This is on top of the extremely arbitrary new physics you have to make up to stop Hawking radiation happening.
Well, I have lots of problems with this too (as implied above). Even so, the fact that the Schwinger discharge doesn't have to cross the event horizon makes it fundamentally different.

I'm intriuged, can you post a link?

Sorry, I don't remember the specific paper that attracted me to this concept. It all had to do with the information paradox. Here's a paper I quickly skimmed that seems to address some of the issues, but I can't vouch for it:
http://arxiv.org/.../9209058

Well, no, what they do is define an ideal sample of white dwarfs at the lower end of magnetic field strength, purely because they make the calculations easier. After all, a charged particle coming directly down at a magnetic pole doesn't experience any deflection at all, no matter how strong the field.


Put most simply then, prove that white dwarfs aren't being consumed by micro black holes. Where are the estimated 10^10 white dwarfs that are supposed to inhabit this, the oldest observable galaxy in the universe? Why aren't astronomers saying:

"Bob, take a look at this! I just found a new planet!"

..."Oh wait, my mistake... It's just another dang blasted white dwarf!"
SkiveHard
not rated yet Feb 01, 2009
@ubavontuba:
"That's like saying big rocks fall faster than small rocks."
Heh. The limiting factor on the rate particles fall into the BH is binding forces in the surrounding medium. The greater the mass of the particle, the greater the pull, the less that matters by comparison. Hammers and feathers only fall at the same rate when theres no other forces acting.

"the fact that the Schwinger discharge doesn't have to cross the event horizon makes it fundamentally different. "

Right, thats where you'd have to stick in the new physics. But it would have to be rather arbitrary new physics, because it would only apply in that particular place.

Re your aversion to charged black holes: I wonder if this comes from reading about the exotic things you could do with a macroscopic black hole with significant charge? Those write ups generally end up by saying that a black hole would never pick up significant charge in reality, because of the mechanisms you mention - the relative weakness of gravity compared to electrostatic charge, for one thing.

Things are very different at the mBH scale. The definition of "significant charge" for one. But more importantly, remember that to get mBHs at all at short range gravity is massively exagerated (actually, its truer to say that at the long ranges we see, the strength of gravity is massively reduced).

"Put most simply then, prove that white dwarfs aren't being consumed by micro black holes."

Erm... for a start... the sample used for this study?
http://arxiv.org/.../0406657

More generally - the ~6% of stars in our back yard that are white dwarfs?

The upshot of the G&M paper is that white dwarfs are essentially impossible obejects to observe (they stick to a sample with low magnetic fields to make their lives easier, but it can be extended to higher fields fairly simply) if (dangerous) black holes can be produced at LHC energies. There would be only black holes.

White dwarfs are observed (including ones with low magnetic fields).

(You could of course argue that the initial population of white dwarfs was unimaginably vast and that we are observing the tiny few that haven't been black holed yet. I can't imagine where you'd get all those white dwarfs from in the first place. More importantly thats inconsistant with the observed dark matter fraction, and also with gravitational microlensing searches.)

That paper you reference - you realise that it argues against Hawking radiation as a solution to the black hole information paradox, rather than against Hawking radition in general, right?
ubavontuba
1 / 5 (1) Feb 02, 2009
@SkiveHard:
Heh. The limiting factor on the rate particles fall into the BH is binding forces in the surrounding medium. The greater the mass of the particle, the greater the pull, the less that matters by comparison. Hammers and feathers only fall at the same rate when theres no other forces acting.
The binding force to be most concerned with in this case is the electrostatic charge. It's stronger than gravity over longer distances and it'd tend to push the more massive, positively charged particles away while attracting the negatively charged particles (thus crowding out the more massive, positively charged particles). Of course, this will depend on if, and how much, gravity varies at small scales.

Right, thats where you'd have to stick in the new physics. But it would have to be rather arbitrary new physics, because it would only apply in that particular place.

I disagree. I don't think an EM signal of any sort can be emitted by a hypothetically stable black hole. This would allow information to leak out about the contents.

Re your aversion to charged black holes: I wonder if this comes from reading about the exotic things you could do with a macroscopic black hole with significant charge? Those write ups generally end up by saying that a black hole would never pick up significant charge in reality, because of the mechanisms you mention - the relative weakness of gravity compared to electrostatic charge, for one thing.

Naw. It has to do with the fact that if they were created by cosmic rays, we'd see 'em interacting with normal matter all over the place.

Things are very different at the mBH scale. The definition of "significant charge" for one. But more importantly, remember that to get mBHs at all at short range gravity is massively exagerated (actually, its truer to say that at the long ranges we see, the strength of gravity is massively reduced).

That's not known for certain, and it's generally debatable. This is something they hope to determine in the experiment, should MBH's be created.

Erm... for a start... the sample used for this study?
http://arxiv.org/.../0406657

First, couldn't you find a reference that's easier to read?

Secondly, 347 white dwarfs hardly constitutes a statisictly significant sample in light of an estimated 10^10 in our galaxy!

More generally - the ~6% of stars in our back yard that are white dwarfs?
Catalogued? Or, presumed?

The upshot of the G&M paper is that white dwarfs are essentially impossible obejects to observe (they stick to a sample with low magnetic fields to make their lives easier, but it can be extended to higher fields fairly simply) if (dangerous) black holes can be produced at LHC energies. There would be only black holes.

That's patently false. They suggest that most of them couldn't even capture a cosmic ray induced MBH to begin with.

White dwarfs are observed (including ones with low magnetic fields).

As one might reasonably expect.

You could of course argue that the initial population of white dwarfs was unimaginably vast and that we are observing the tiny few that haven't been black holed yet. I can't imagine where you'd get all those white dwarfs from in the first place. More importantly thats inconsistant with the observed dark matter fraction, and also with gravitational microlensing searches.)
Again, this is a patently false conjecture. A large percentage would likely be relatively immune. No extra ones are required.

That paper you reference - you realise that it argues against Hawking radiation as a solution to the black hole information paradox, rather than against Hawking radition in general, right?

I wasn't using it in that context. I was using it to provide an example of a limiting problem in regards to charged MBH's.
SkiveHard
not rated yet Feb 03, 2009
"I disagree. I don't think an EM signal of any sort can be emitted by a hypothetically stable black hole. This would allow information to leak out about the contents. "

Well, yes. That was why Hawking looked at the effect in the first place. If black holes don't emit then the second law of thermodynamics is screwed.

"Naw. It has to do with the fact that if they were created by cosmic rays, we'd see 'em interacting with normal matter all over the place. "

Well we agree on that, at least.

"That's not known for certain, and it's generally debatable. This is something they hope to determine in the experiment, should MBH's be created."

Well, no. I have no idea if theories involving large extra dimensions are true, but the "turning up" of gravity at short distances is exactly what might let you create mBHs below the Planck scale in the first place.

"First, couldn't you find a reference that's easier to read? "

Sorry, first one that came to hand. But the point here was that 347 is statistically significant in that it is not 0.

If you want some more, try this:
http://arxiv.org/.../0606700
9000 odd from one particular survey. I believe that 6% is an extrapolation from surveys like this.

"That's patently false. They suggest that most of them couldn't even capture a cosmic ray induced MBH to begin with. "

Check section 6.2 (toward the end). In the most conservative case, they still expect more than 100 black holes stopped in each white dwarf per 50 million years. White dwarf ages are in the billions of years. So as I said, seeing any white dwarfs at all means no black holes at LHC energies.
ubavontuba
1 / 5 (1) Feb 04, 2009
Well, yes. That was why Hawking looked at the effect in the first place. If black holes don't emit then the second law of thermodynamics is screwed.
Call me a rebel if you like, but I'm not so sure it isn't.

Well we agree on that, at least.
It's a start.

Well, no. I have no idea if theories involving large extra dimensions are true, but the "turning up" of gravity at short distances is exactly what might let you create mBHs below the Planck scale in the first place.
...supposedly, anyway.

Have you read much about the RHIC fireball?

Sorry, first one that came to hand. But the point here was that 347 is statistically significant in that it is not 0.
That's only 0.00000347% of the estimated total! That's to say, 99.999996% of them could have been destroyed long ago, and we wouldn't know it.

If you want some more, try this:
http://arxiv.org/.../0606700
9000 odd from one particular survey. I believe that 6% is an extrapolation from surveys like this.

That's still an insignificant 0.00009316%. Besides, has anyone gone back to see if they're all still there?

Check section 6.2 (toward the end). In the most conservative case, they still expect more than 100 black holes stopped in each white dwarf per 50 million years. White dwarf ages are in the billions of years. So as I said, seeing any white dwarfs at all means no black holes at LHC energies.
That's a (disputable) statistical average. Some are simply going to be more, or less, susceptible than others. Perhaps 9,316 are relatively immune... :)
SkiveHard
not rated yet Feb 04, 2009
"Call me a rebel if you like, but I'm not so sure it isn't."

Well thats... an opinion. I was just a bit surprised to see you using information from a black hole as an argument against Hawking radiation, when its an argument for it.

"...supposedly, anyway. "

Well no, not really. In the standard picture you get no black holes below the Planck scale, to get ones at LHC energies you have to turn up gravity somehow.

"Have you read much about the RHIC fireball?"

Well, yes, as it happens, though I'm not sure what you're getting at. You do realize that it was seen as an excellent _analogy_ of a black hole, right? Something that could be studied to learn about black holes (with the Coulomb potential standing in for gravitational interaction), but not the real region-of-space-time-from-which-nothing-can-escape deal? It was widely misreported at the time, I suspect from a misreading of Nastase's paper:

http://arxiv.org/.../0501068

Hard to see where the confusion came from, given that the word "analog" is right there in the first sentence of the abstract. Maybe the journalists didn't read any further than the title? Nah, surely not.

"99.999996% of them could have been destroyed long ago, and we wouldn't know it."

Right, time to break out the maths.

Lets say we observe just one single white dwarf with the characteristics that G&M use to describe their ideal sample. Low magnetic field, sufficient size, sufficient density, and lets say more than 5 billion years old to make the sums easy. (All these properties can be measured directly for individual stars).

G&M give the expected number of black holes stopped in such a star over its lifetime (10,000) - but as you say, thats just an average. Stars which had stopped 0 black holes, and therefore still survive, are by no means impossible.

Hows your stats? The Poisson distribution concerns independent events happening in a given period of time. For an expected number of events "L", the probability of seeing "k" events actually happen is L^k e^(-L)/k!.

G&M have given us L (10,000), and since we're looking for the probability of 0 events, it all becomes easier - L^0=1 and 0!=1, so we're left with e^-10000 (thats e to the power of -10000). If you get a calculator and work that out you'll see why I say that the observation of a _single_ white dwarf (lets say one with low magnetic field to keep it simple) rules out the chances of black holes at LHC energies. And plenty have been observed.

Some additional things - G&M's analysis requires only an object of a given density, size, magnetic field and that has been around long enough. It just happens that white dwarfs fit those characteristics, theres nothing special about them otherwise (and those characteristics can be measured individually, star by star). Also, you might wonder if G&M have messed up their calculations somehow - but you can see that the margin for error here is absolutely enormous. They could have got things astonishingly wrong, and their conclusion would still hold.
ubavontuba
1 / 5 (1) Feb 08, 2009
Well thats... an opinion. I was just a bit surprised to see you using information from a black hole as an argument against Hawking radiation, when its an argument for it.
Actually, I'm arguing against it altogether. I'm suggesting (have suggested) that black holes cannot exhibit charge. If charge and Hawking radiation are allowed, I see nothing but conservation violations.

Well no, not really. In the standard picture you get no black holes below the Planck scale, to get ones at LHC energies you have to turn up gravity somehow.
I think it might be possible in GR. The kinetic energy in the rest frame, between the colliding particles, needs to be considered as part of the total mass at the time of the collision - emerging from a two-dimensional plane - between the colliding particles.

Well, yes, as it happens, though I'm not sure what you're getting at. You do realize that it was seen as an excellent _analogy_ of a black hole, right? Something that could be studied to learn about black holes (with the Coulomb potential standing in for gravitational interaction), but not the real region-of-space-time-from-which-nothing-can-escape deal? It was widely misreported at the time, I suspect from a misreading of Nastase's paper:

http://arxiv.org/.../0501068

Hard to see where the confusion came from, given that the word "analog" is right there in the first sentence of the abstract. Maybe the journalists didn't read any further than the title? Nah, surely not.
Actually, one of the authors subsequently claimed it was a black hole (more or less - I forget the exact wording).

Right, time to break out the maths.

Lets say we observe just one single white dwarf with the characteristics that G&M use to describe their ideal sample. Low magnetic field, sufficient size, sufficient density, and lets say more than 5 billion years old to make the sums easy. (All these properties can be measured directly for individual stars).

G&M give the expected number of black holes stopped in such a star over its lifetime (10,000) - but as you say, thats just an average. Stars which had stopped 0 black holes, and therefore still survive, are by no means impossible.

Hows your stats? The Poisson distribution concerns independent events happening in a given period of time. For an expected number of events "L", the probability of seeing "k" events actually happen is L^k e^(-L)/k!.

G&M have given us L (10,000), and since we're looking for the probability of 0 events, it all becomes easier - L^0=1 and 0!=1, so we're left with e^-10000 (thats e to the power of -10000). If you get a calculator and work that out you'll see why I say that the observation of a _single_ white dwarf (lets say one with low magnetic field to keep it simple) rules out the chances of black holes at LHC energies. And plenty have been observed.

Some additional things - G&M's analysis requires only an object of a given density, size, magnetic field and that has been around long enough. It just happens that white dwarfs fit those characteristics, theres nothing special about them otherwise (and those characteristics can be measured individually, star by star). Also, you might wonder if G&M have messed up their calculations somehow - but you can see that the margin for error here is absolutely enormous. They could have got things astonishingly wrong, and their conclusion would still hold.
Oh bro-ther! That's the worst application of probability math I've ever seen! Your result is given in the setup! Obviously, if you have one white dwarf that has a black hole stop in it 10,000 times over 5 billion years, you can guarantee it's going to happen at least once (duh).
ubavontuba
1 / 5 (1) Feb 09, 2009
On the RHIC fireball:

The RHIC website:

http://www.bnl.go...oles.htm

...has some very interesting inferences regarding this. They're obviously trying to sidestep the issue by stating it's not a "star-swallowing" black hole. But, do they deny it might be a nano-black-hole? I think not.

It is clear by this statement:

"Horatiu is referring to a mathematical similarity between the physics of the real world, which govern RHIC collisions, and the physics that scientists use to describe a theoretical, %u201Cimaginary%u201D black hole in a hypothetical world with a different number of space-time dimensions (more than the four dimensions %u2014 three space directions and time %u2014 that exist in our world)."

...they are stating that "real world physics" (general relativity and quantum mechanics) cannot describe the properties of the fireball, whereas in string theory, it is indeed described properly as a black hole.

Here:

http://www.aps.or...arch.cfm

...it is implied that it was something more than a QGP. Note the statement:

"John Cramer (University of Washington) speculated that such a violently exploding fireball may mean that RHIC is operating at energies higher than those required for creating a QGP..."
SkiveHard
not rated yet Feb 09, 2009
"Oh bro-ther! That's the worst application of probability math I've ever seen! Your result is given in the setup! Obviously, if you have one white dwarf that has a black hole stop in it 10,000 times over 5 billion years, you can guarantee it's going to happen at least once (duh)."

Well, what I gave you is the probability for a given white dwarf to still be there 5 billion years later, (given the hypothesis that dangerous black holes can be created at LHC energies). I was kind of hoping you were going to run with it from there... but OK.

Look at it this way - lets imagine the highest possible initial population of white dwarfs. Start with a volume of space - ideally it would be the volume of space thats been looked at to see if white dwarfs are in it, but I'm damned if I'll waste time trying to work that out, so lets use the entire observable universe instead - roughly 50 billion light years in every direction, which is, what 500 billion quadrillion meters? So a total volume that is definitely less than 10^90 cubic meters. Now lets suppose that that space is completely filled with white dwarfs. I can't be bothered to estimate the volume of a white dwarf, but you'll agree that its more than a cubic meter, right? So the initial number of white dwarfs is smaller than 10^90. If we believe the hypothesis that dangerous black holes can be created at LHC energies, we can calculate that the probability for each of those white dwarfs to make it to the present day is less than 10^-3000.

What you can see from that is that for any sane required "level of confidence", the observation of a single remaining white dwarf forces us to reject that hypothesis (and we observe many).

Hope that was helpful.
SkiveHard
not rated yet Feb 09, 2009
While I'm here:

"If charge and Hawking radiation are allowed, I see nothing but conservation violations. "

Can you expand on that?

"I think it might be possible in GR. The kinetic energy in the rest frame, between the colliding particles, needs to be considered as part of the total mass at the time of the collision - emerging from a two-dimensional plane - between the colliding particles. "

Well, if you're looking at classical GR then every single point particle is a black hole - which would seem to be a problem. But QM puts a hard limit on the minimum mass of a black hole - read up on the Planck scale if you want to know more. Its possible to get around that if you live in a universe where gravity gets turned up short distances.

And yes, as you say, the maximum mass of the black hole is the sum of the energies of the coliding particles in the center of mass - which is 14TeV maximum for the LHC. But thats massively below the 10^16 TeV needed for a "conventional" mBH.

"...has some very interesting inferences regarding this. They're obviously trying to sidestep the issue by stating it's not a "star-swallowing" black hole. But, do they deny it might be a nano-black-hole? I think not."

Actually, yes, they do explicitly deny that. They're talking about the Nastase paper (I linked to it above) which explicitly, in the first line of its abstract, states that its talking about the fireball as an _analogue_ of a black hole. If you don't belive me, or them, look for yourself.

In your second link they're not actually talking about black holes at all - what they're talking about is the posibility that they've created a Quark Gluon Plasma (QGP) which is pretty much what
RHIC is there for. One of the researchers reckons they are there already, the rest are more cautious.

But I confess, I don't know much about RHIC. The web page is http://www.bnl.gov/rhic/ . If you search around a bit you can find some contact email adresses and ask people who really know what they're talking about.
ubavontuba
1 / 5 (1) Feb 14, 2009
Well, what I gave you is the probability for a given white dwarf to still be there 5 billion years later, (given the hypothesis that dangerous black holes can be created at LHC energies). I was kind of hoping you were going to run with it from there... but OK.
Oh bro-ther! That's a cop-out. I caught you playing shenanigans with math (trying to look authoritative), and you know it.

Look at it this way - lets imagine the highest possible initial population of white dwarfs. Start with a volume of space - ideally it would be the volume of space thats been looked at to see if white dwarfs are in it, but I'm damned if I'll waste time trying to work that out, so lets use the entire observable universe instead - roughly 50 billion light years in every direction, which is, what 500 billion quadrillion meters? So a total volume that is definitely less than 10^90 cubic meters. Now lets suppose that that space is completely filled with white dwarfs. I can't be bothered to estimate the volume of a white dwarf, but you'll agree that its more than a cubic meter, right? So the initial number of white dwarfs is smaller than 10^90. If we believe the hypothesis that dangerous black holes can be created at LHC energies, we can calculate that the probability for each of those white dwarfs to make it to the present day is less than 10^-3000.

What you can see from that is that for any sane required "level of confidence", the observation of a single remaining white dwarf forces us to reject that hypothesis (and we observe many).
Oh bro-ther! Is it that you don't understand statistical probabilities at all, or are you simply playing games? For one, their exposure isn't going to be uniform.

Hope that was helpful. It certainly was humorous!
ubavontuba
1 / 5 (1) Feb 15, 2009
Can you expand on that?
I already alluded to an instance, in regards to Hawking radiation, in a previous reply. ...but that's not the point of this discussion.

Well, if you're looking at classical GR then every single point particle is a black hole - which would seem to be a problem. But QM puts a hard limit on the minimum mass of a black hole - read up on the Planck scale if you want to know more. Its possible to get around that if you live in a universe where gravity gets turned up short distances.

And yes, as you say, the maximum mass of the black hole is the sum of the energies of the coliding particles in the center of mass - which is 14TeV maximum for the LHC. But thats massively below the 10^16 TeV needed for a "conventional" mBH.
It depends on how you view the transition from QM to GR and vice versa. If GR is correct for gravity to the extreme, then gravity hypothetically might function at smaller scales than QM.

Actually, yes, they do explicitly deny that. They're talking about the Nastase paper (I linked to it above) which explicitly, in the first line of its abstract, states that its talking about the fireball as an _analogue_ of a black hole. If you don't belive me, or them, look for yourself.
I disagree with your interpretation. The quote I provided was in the proper context.

In your second link they're not actually talking about black holes at all - what they're talking about is the posibility that they've created a Quark Gluon Plasma (QGP) which is pretty much what
RHIC is there for. One of the researchers reckons they are there already, the rest are more cautious.
I think it's quite clear the reasearcher was alluding to an even greater possibility.

But I confess, I don't know much about RHIC. The web page is http://www.bnl.gov/rhic/ . If you search around a bit you can find some contact email adresses and ask people who really know what they're talking about.
I've been around.

Besides, we're getting pretty far off the beam. The point of this discussion is that too many scientists spew out the "cosmic rays do it all the time" argument without having a clue as to what they're saying.
SkiveHard
not rated yet Feb 16, 2009
"Oh bro-ther! That's a cop-out. I caught you playing shenanigans with math (trying to look authoritative), and you know it."

Now now, if you're going to be rude this will cease to be a fun argument. I would never claim to be authoritative (hard to claim authority when you're just some guy on the internet). My point with the absurdly low probability is that 10^3000 or so is a physically impossible number to get to for an initial population - which is what I was getting at with that little Fermi problem. Wasn't planning on developing the argument formally, but there you go.

Maybe I should explain what I'm trying to show here. I don't know your background, so I'm going to assume you know what I mean by hypothesis testing (if thats not true, the wikipedia page was not badly wrong the last time I looked). So what you need is a hypothesis (dangerous black holes can be produced at LHC energies) an observation (at least one white dwarf of the type specified by G&M is observed) and an agreed upon level of confidence under which you would reject that hypothesis (99.99999999999%, if you like. This is unusually high, but then its an unusual problem). And my point is that under those criteria, you are forced to reject the hypothesis.

The point here is that I'm not trying to calculate these numbers exactly - I'm using conservative estimates so that I'm always _over_estimating the probability of a white dwarf surviving to the present day. The number I used for the initial population of white dwarfs (10^90)- you agree thats ridiculously large, right?

"For one, their exposure isn't going to be uniform. "
Well, yes, indeed. Unless I've missed what you're getting at, yes, the number of cosmic rays of sufficient energy, hitting in just the right way to cause a black hole is an inherently random number. But if we know the _average_ rate at which it happens (which G&M calculate for us), we can calculate the probability of it happening a given number of times in a given amount of time - using the Poisson distribution. And for a given white dwarf to survive, it must have happened exactly 0 times (and thats an extraordinarily unlikely thing, which was my original point).

Anyway, if thats not what you were getting at, my apologies, please explain what you meant.
SkiveHard
not rated yet Feb 16, 2009
"It depends on how you view the transition from QM to GR and vice versa. If GR is correct for gravity to the extreme, then gravity hypothetically might function at smaller scales than QM. "

And here we kind of hit the limit of what you can usefully argue about in comments - but what the hell. Its not a case of whether GR continues to be correct - what you would need is for QM to be flat wrong, and for things like the uncertainty principle to be completely incorrect.

Also, if you are trying to use classical GR to describe fundamental particles (electrons, quarks etc) then you find that they're black holes already (being point particles). Which is an interesting state of affairs.

"I disagree with your interpretation. The quote I provided was in the proper context."

Interpretation is the problem here - I say he means one thing , you say he means another. Can I suggest that trying to get to the truth using quotes from a press release is not the best way forward? If you want to know what the scientist in question (Nastase) actually thought, the thing to do is read it first hand, in his paper:

http://arxiv.org/.../0501068

He says, in the first line of his abstract, that the fireball is an excellent _analogue_ of a black hole.

"I think it's quite clear the reasearcher was alluding to an even greater possibility."

Well, I don't see it, but why not email John Cramer and ask? His address will be out there somewhere.

'The point of this discussion is that too many scientists spew out the "cosmic rays do it all the time" argument without having a clue as to what they're saying.'

And my point is that if they are including in that an implicit "given some very basic assumptions about how stuff works" then that statement is absolutely fine. Which brings us nicely full circle.
ubavontuba
1 / 5 (1) Feb 21, 2009
Now now, if you're going to be rude this will cease to be a fun argument. I would never claim to be authoritative (hard to claim authority when you're just some guy on the internet). My point with the absurdly low probability is that 10^3000 or so is a physically impossible number to get to for an initial population - which is what I was getting at with that little Fermi problem. Wasn't planning on developing the argument formally, but there you go.

Maybe I should explain what I'm trying to show here. I don't know your background, so I'm going to assume you know what I mean by hypothesis testing (if thats not true, the wikipedia page was not badly wrong the last time I looked). So what you need is a hypothesis (dangerous black holes can be produced at LHC energies) an observation (at least one white dwarf of the type specified by G&M is observed) and an agreed upon level of confidence under which you would reject that hypothesis (99.99999999999%, if you like. This is unusually high, but then its an unusual problem). And my point is that under those criteria, you are forced to reject the hypothesis.

The point here is that I'm not trying to calculate these numbers exactly - I'm using conservative estimates so that I'm always _over_estimating the probability of a white dwarf surviving to the present day. The number I used for the initial population of white dwarfs (10^90)- you agree thats ridiculously large, right?
The population is actually irrelvent...

Well, yes, indeed. Unless I've missed what you're getting at, yes, the number of cosmic rays of sufficient energy, hitting in just the right way to cause a black hole is an inherently random number. But if we know the _average_ rate at which it happens (which G&M calculate for us), we can calculate the probability of it happening a given number of times in a given amount of time - using the Poisson distribution. And for a given white dwarf to survive, it must have happened exactly 0 times (and thats an extraordinarily unlikely thing, which was my original point).
But not for every individual white dwarf...

Anyway, if thats not what you were getting at, my apologies, please explain what you meant.

Let's suppose there are a presumed total of 10 white dwarfs in the entire universe, but we can only observe one of them. Suppose 10,000 black hole events in 5 billion years as an average per white dwarf. Your math works out to the same result, right?

Let's suppose the white dwarf we can observe is completely immune for an unspecified reason (or reasons), but you don't know it. It receives no black holes, but the others actually each receive an average of 11,111.11 Now, we have one survivor that apparently defies your prediction. The math is the same, but there it is, nonetheless. It therefore (according to you) apparently falsifies the whole notion of cosmic ray induced black holes - even though its nine brothers have all collapsed into black holes!

Is your math wrong? Or, is it that your application of the math is wrong? Do you see now how easy it is to falsify your contention?

You can't know that each and every one has sufficient exposure to fall victim to your prediction. The ones we see might simply be particularly hardy.
ubavontuba
1 / 5 (1) Feb 21, 2009
And here we kind of hit the limit of what you can usefully argue about in comments - but what the hell. Its not a case of whether GR continues to be correct - what you would need is for QM to be flat wrong, and for things like the uncertainty principle to be completely incorrect.
I think the supposed conflict is overrated.

Also, if you are trying to use classical GR to describe fundamental particles (electrons, quarks etc) then you find that they're black holes already (being point particles). Which is an interesting state of affairs.
Why can't the two theories simply coincide - where QM works for particles and forces (but not gravity) and GR works for spacetime/gravity (but not particles and forces)?

Sure, it's scientific blasphemy. But if you play with the notion for awhile, it begins to make sense...

Interpretation is the problem here - I say he means one thing , you say he means another. Can I suggest that trying to get to the truth using quotes from a press release is not the best way forward? If you want to know what the scientist in question (Nastase) actually thought, the thing to do is read it first hand, in his paper:

http://arxiv.org/.../0501068

He says, in the first line of his abstract, that the fireball is an excellent _analogue_ of a black hole.
The paper predates the article. Also, writing a paper demands a less speculative standard and may not reflect the author's complete interpretation.

Well, I don't see it, but why not email John Cramer and ask? His address will be out there somewhere.
I sent a question (hopefully to the right address). I'll let you know if he responds.

And my point is that if they are including in that an implicit "given some very basic assumptions about how stuff works" then that statement is absolutely fine. Which brings us nicely full circle.
Obviously, this is not the case. Stéphane Coutu explicitly states "The WORLD is constantly bombarded by energetic cosmic rays..." not, "the existence of ancient white dwarfs indicate..."
SkiveHard
not rated yet Feb 23, 2009
"Let's suppose the white dwarf we can observe is completely immune for an unspecified reason (or reasons), but you don't know it."

Ah! Right, now we're getting somewhere. The chain of reasoning I laid out only works on the assumption that G&M are giving us a good estimate for the rate of stopped black holes in white dwarfs, and that it works for _all_ white dwarfs (of the type that they specify). If thats true then there are no white dwarfs that are immune "for some reason". And this is the critical point - if it holds then you really do have to reject the hypothesis of dangerous black holes at LHC energies.

And my point is that its a really robust assumption. Remember, theres nothing special about white dwarfs, G&M just need a big enough, dense enough target to stop mBHs. And the size and density are things you can measure - you can look at a given star, see that it is big and dense enough to stop mBHs at the rate G&M predict and see that its still there.

You could claim that all the observations of white dwarfs are flat out wrong. I suspect that wouldn't be a very productive line of attack.
ubavontuba
1 / 5 (2) Feb 25, 2009
Ah! Right, now we're getting somewhere. The chain of reasoning I laid out only works on the assumption that G&M are giving us a good estimate for the rate of stopped black holes in white dwarfs, and that it works for _all_ white dwarfs (of the type that they specify).
That's a lot of assuming, don't you think?

If thats true then there are no white dwarfs that are immune "for some reason". And this is the critical point - if it holds then you really do have to reject the hypothesis of dangerous black holes at LHC energies.
How might you prove it? How might you falsify it?

And my point is that its a really robust assumption. Remember, theres nothing special about white dwarfs, G&M just need a big enough, dense enough target to stop mBHs. And the size and density are things you can measure - you can look at a given star, see that it is big and dense enough to stop mBHs at the rate G&M predict and see that its still there.

You could claim that all the observations of white dwarfs are flat out wrong. I suspect that wouldn't be a very productive line of attack.

Oh brother. You'll buy anything - hook, line, and sinker - that supports your point of view. Let's use our critical thinking skills and ask a few questions to test these "robust assumptions:"

1. If your contention is true, white dwarfs should be everywhere apparent. That's to say that in this, the oldest observable galaxy in the universe, white dwarfs should abound. It's commonly estimated there are 10^10 in our galaxy, alone. Where are they? Why have they proven so elusive?

2. How do you know the relatively few white dwarfs we've found aren't protected? What magnetic field properties do they possess? What are their rotation periods? What are their axial tilts? What regions are they located in? Any correlations between these regions (starfield densities, gas/dust densities, other variants)? Do they lie within, or without, the galactic plane? Are the ones we have observed even all still there? (has anyone checked?)

3. What do we know of cosmic rays? What is their origin? Are they a local phenomena? regional galactic? regional universal? universal?

4. (and most important) What are the properties of micro black holes? How big are they? What might their absorption cross sections at relativistic velocities look like? How can we possibly presume to know this?

Obviously, your contention can be no more than a mild speculation, without knowing a great deal more than we know. That last is particularly noteworthy - because G&M presumed properties for the micro black holes that they couldn't possibly know!

Most of these questions are currently untestable at this time. The first is the most obvious and easiest to test. Therefore, unless you can verify the existence of a great number of white dwarfs (a substantial percentage of the presumed dispersion in several given regions, for instance), your contention is invalid.
ubavontuba
1 / 5 (1) Feb 25, 2009
I should add that if you do find a substantial population of white dwarfs, you're only proving G&M are WRONG in regards to the micro black hole properties. Therefore, the existence of a substantial population of white dwarfs doesn't necessarily prove the safety of the LHC.
SkiveHard
not rated yet Feb 25, 2009
These are all excellent questions that get right to the heart of it. I'll have a go at answering some at least.

"If your contention is true, white dwarfs should be everywhere apparent."

1) That doesn't actually follow from my argument, but as it happens they are. They're not very bright, so theres a limit to how far away you can see them, but when you go looking for them they turn up by the bucketload (I think I gave you a link to the sloan survey somewhere above). But check it out for yourself, they're pretty much common as dirt.

(By the way, you're not expecting astronomers to go and count every single white dwarf for you, are you? Its a big sky... the best they can do is pick a patch of sky, work out how many they should see and see how that compare with what they actually get. Conclusion from studies done: white dwarfs are
very common things.)

2) Much as I hate to point to wikipedia, the white dwarf page there looks to be pretty reasonable. It explains how you _measure_ the field, mass and density etc of a white dwarf that you've observed. Like I said, all G&M need is a target of a given size and density (and field). These quantities are all testable on a case by case basis. As we established earlier on, it is (effectively) impossible for a vulnerable white dwarf to survive till the present day (if G&M are right and if you can make black holes at LHC energies). So you would only see _invulnerable_ white dwarfs under those circumstances. And... thats not the case. The G&M paper includes references to observations of white dwarfs that specifically _would_ be vulnerable.

3) Protons of the energies we're looking at? Supernovae, probably. But the important question is - are they coming from a single, close by, source? That would screw up the argument. And the answer is no - they come in from all over the place, which rules that out.

4. Ah, the real meat of the argument. This is the really neat bit of the particular approach G&M have used. Have you seen the particular mechanism they are relying on to stop black holes in a white dwarf?

More in a bit... (also just seen that I didn't reply to you r other post)
SkiveHard
not rated yet Feb 25, 2009
So to continue - the beauty of G&M's approach is that what stops the black hole in the white dwarf is nothing other than its tendancy to suck up matter as it goes. It gains mass as it absorbs stuff but its momentum remains the same - so its velocity drops, eventually below escape velocity. Its neat because it requires nothing of the black hole except the thing that makes it dangerous. The drawback is that it only works in sufficiently dense objects - which is the reason for the whole white dwarf thing.

But the natural question is - what if their calculations are wrong? What if black holes suck in matter too slowly to cause the velocity to drop enough, and they pass through the white and are still going too fast to be caught?

Well, this actually happens for some of the possible types of black hole they look at. But thats fine, because they also show that these black holes suck in matter too slowly to destroy the earth (before it would be wiped out by the sun anyway). And thats no coincidence - its a general result that if a black hole isn't "sucky" enough to take out a white dwarf, it isn't "sucky" enough to take out the earth either.

Like I said, its a really tidy piece of work.
SkiveHard
not rated yet Feb 26, 2009
So to reply top your other post:

"Why can't the two theories simply coincide - where QM works for particles and forces (but not gravity) and GR works for spacetime/gravity (but not particles and forces)?

Sure, it's scientific blasphemy. But if you play with the notion for awhile, it begins to make sense..."

Not blasphemy at all! What you've described is the default position in physics for the past ~century. And it works just fine - because the observations you can actually make are either totally dominated by gravity, or gravity is completely irrelevant. The problem comes when that isn't the case - gravity is too big to ignore, but quantum mechanical effects are too big to ignore too. Even if you arbitrarily decided to draw a line, and say QM on this side, GR on this, the problem is that the two theories in no way meet up on that line - they are fundamentally different. One way or another, you need a new theory to fill that gap.

(A ~century of trying has led to the conclusion that its quite hard to do.)

"The paper predates the article. Also, writing a paper demands a less speculative standard and may not reflect the author's complete interpretation."

Just noticed that theres actually a link from that article to a page describing how the misconception that it was a "real" black hole started - apparently it got misreported on the BBC site and spread from there. And the meme lives, apparently.

'Obviously, this is not the case. Stéphane Coutu explicitly states "The WORLD is constantly bombarded by energetic cosmic rays..." not, "the existence of ancient white dwarfs indicate..."'

Two different arguments - the "cosmics hitting the earth" argument has been around for years, G&M's argument is new. The old argument works, _provided_ you make some assumptions about the way physics works. The G&M argument doesn't require you to do that - but it does require you to know what white dwarfs are, how many of them there are, what you can know about them from observations, what the cosmic ray spectrum is, what you can know about cosmic rays there as opposed to here... All things you can go and observe, rather than relying on a particular assumption of the way physics works.

So in that sense, the G&M argument is a much better, simpler argument. But you will notice, that in trying to get to the bottom of what they are talking about we have ended up with comments much longer than the original article. And thats why most people talking about LHC safety are going to cop out and give the easy to explain, but less good argument. Can you really blame them?
ubavontuba
1 / 5 (1) Mar 01, 2009
These are all excellent questions that get right to the heart of it. I'll have a go at answering some at least.
It appears you only glossed over them.

1) That doesn't actually follow from my argument, but as it happens they are. They're not very bright, so theres a limit to how far away you can see them, but when you go looking for them they turn up by the bucketload (I think I gave you a link to the sloan survey somewhere above). But check it out for yourself, they're pretty much common as dirt.
As we've already discussed, this simply isn't true. They've found a relative, very few.

Is it your intent to ignore previously discussed information?

(By the way, you're not expecting astronomers to go and count every single white dwarf for you, are you? Its a big sky... the best they can do is pick a patch of sky, work out how many they should see and see how that compare with what they actually get.

Uh, that's similar to what I already said!

Conclusion from studies done: white dwarfs are
very common things.)
What studies? As already discussed, the Sloan Digital Sky Survey only found 9,134.

2) Much as I hate to point to wikipedia, the white dwarf page there looks to be pretty reasonable. It explains how you _measure_ the field, mass and density etc of a white dwarf that you've observed. Like I said, all G&M need is a target of a given size and density (and field). These quantities are all testable on a case by case basis.

Fine. How many of the various types have they found? Specifically, how many of the supposedly most vulnerable?

As we established earlier on, it is (effectively) impossible for a vulnerable white dwarf to survive till the present day (if G&M are right and if you can make black holes at LHC energies).

That's patently false. Even G&M admit that even the very densest could be protected by other means.

Is it your intent to use patently false information to support your views?

So you would only see _invulnerable_ white dwarfs under those circumstances. And... thats not the case. The G&M paper includes references to observations of white dwarfs that specifically _would_ be vulnerable.
Hardly a statistically significant population! I think they only provided eight examples! This population is so small, they could easily be special cases!

Really, where are the supposed BILLIONS of white dwarfs?

And of course, this supposes that G&M are absolutely correct in their speculations on micro black hole properties (like that ever happens).

I would particularly argue with their interpretation of it as a particle.

3) Protons of the energies we're looking at? Supernovae, probably.
I disagree. This would tend to be a rather sporadic source. As far as I know, no one has traced a cosmic ray to any particular source.

But the important question is - are they coming from a single, close by, source? That would screw up the argument. And the answer is no - they come in from all over the place, which rules that out.
You mean they come in from all over the place, LOCALLY. You can't know what their distribution is universally, without knowing their source.

4. Ah, the real meat of the argument. This is the really neat bit of the particular approach G&M have used. Have you seen the particular mechanism they are relying on to stop black holes in a white dwarf?
Yes. What's your point?

More in a bit... (also just seen that I didn't reply to you r other post)

ubavontuba
1 / 5 (1) Mar 01, 2009
So to continue - the beauty of G&M's approach is that what stops the black hole in the white dwarf is nothing other than its tendancy to suck up matter as it goes. It gains mass as it absorbs stuff but its momentum remains the same - so its velocity drops, eventually below escape velocity. Its neat because it requires nothing of the black hole except the thing that makes it dangerous. The drawback is that it only works in sufficiently dense objects - which is the reason for the whole white dwarf thing.

Well, this is as one might expect. However, they also use scattering.

But the natural question is - what if their calculations are wrong? What if black holes suck in matter too slowly to cause the velocity to drop enough, and they pass through the white and are still going too fast to be caught?

Well, this actually happens for some of the possible types of black hole they look at. But thats fine, because they also show that these black holes suck in matter too slowly to destroy the earth (before it would be wiped out by the sun anyway). And thats no coincidence - its a general result that if a black hole isn't "sucky" enough to take out a white dwarf, it isn't "sucky" enough to take out the earth either.
Oh brother. Relativistic accretion and rest accretion don't necessarily correlate. Particularly in the case where the accretion mass is reactive to the presence of the micro black hole.

Also, the correlation between mass and accretion rates can vary widely, depending on the properties of the micro black hole. If it's more like a GR micro black hole (for instance), its diameter (and therefore relativistic accretion profile) is dramatically reduced, whereas its rest accretion rate would generally be unchanged.

Like I said, its a really tidy piece of work.
Hardly!
ubavontuba
1 / 5 (1) Mar 01, 2009
Not blasphemy at all! What you've described is the default position in physics for the past ~century. And it works just fine - because the observations you can actually make are either totally dominated by gravity, or gravity is completely irrelevant. The problem comes when that isn't the case - gravity is too big to ignore, but quantum mechanical effects are too big to ignore too. Even if you arbitrarily decided to draw a line, and say QM on this side, GR on this, the problem is that the two theories in no way meet up on that line - they are fundamentally different. One way or another, you need a new theory to fill that gap.

(A ~century of trying has led to the conclusion that its quite hard to do.)
I mean it in a much stricter sense. That is, the two theories coincide - even at quantum scales.

Just noticed that theres actually a link from that article to a page describing how the misconception that it was a "real" black hole started - apparently it got misreported on the BBC site and spread from there. And the meme lives, apparently.
My referenced quotations and remarks stand. Like I said, they are stating that "real world physics" (general relativity and quantum mechanics) cannot describe the properties of the fireball, whereas in string theory, it is indeed described properly as a black hole.

Two different arguments - the "cosmics hitting the earth" argument has been around for years, G&M's argument is new. The old argument works, _provided_ you make some assumptions about the way physics works.
You mean like WRONG assumptions?

The G&M argument doesn't require you to do that - but it does require you to know what white dwarfs are, how many of them there are, what you can know about them from observations, what the cosmic ray spectrum is, what you can know about cosmic rays there as opposed to here... All things you can go and observe, rather than relying on a particular assumption of the way physics works.
And as I've stated, the observations aren't significant enough upon which to draw conclusions.

And also: Even if you do find a substantial population of white dwarfs, you're only proving G&M are WRONG in regards to their micro black hole property assumptions. Therefore, the existence of a substantial population of white dwarfs doesn't necessarily prove the LHC is safe.

So in that sense, the G&M argument is a much better, simpler argument. But you will notice, that in trying to get to the bottom of what they are talking about we have ended up with comments much longer than the original article. And thats why most people talking about LHC safety are going to cop out and give the easy to explain, but less good argument. Can you really blame them?
Yes. Bad science is BAD SCIENCE.
QubitTamer
1 / 5 (1) Aug 06, 2009
Correct me if I'm wrong, but don't we have generaly the same amount of energy in particle collisions in the upper atmosphere? Are we dead? I'm pretty sure the sun has much more energetic reactions. Has a black hole been created inside the sun?
Frankly, at this point, only complete morons and people who enjoy being frightened have any reason to be fearful.


If a black hole has been formed inside the sun it would take some time for us to know... there is a LOT of mass inside the sun that would need to fall into the BH before we would likely notice.... the sun would not just crumple up in a matter of minutes... however a black hole falling through the earth would have a lot less mass to ingest before we became aware of it...it would fall through the earth in an internal elliptical orbit around the center point of mass in the earth's core... it would also pick up speed and likely shoot out through the crust and into the atmosphere eventually falling back down through the ocean and /or crust like a runaway bola...

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