Why the LHC Won't Destroy the World 508
An anonymous reader writes "Most people are aware of the recent articles contending that the Large Hadron Collider at CERN might destroy the world. While most scientists have no such concerns, a recent preprint released to arxiv systematically dismantles the notion. The gist of the argument is this: Everything that will be created at the LHC is already being created by cosmic rays. If a black hole created by the LHC is interactive enough to destroy the world within the lifetime of the sun, similar black holes are already being created by cosmic rays. Such black holes would be stopped by dense cosmic objects (neutron stars and white dwarfs). A black hole stopped in one of these objects would eventually absorb it. We see sufficiently old neutron stars in the sky, thus any black hole that could be created at the LHC, even if it is stable, would have no effect on the earth on any meaningful timescale."
First (Score:5, Funny)
First particle?
Famous "last particle" (Score:5, Funny)
"We have an unintended event horizon."
Re:Famous "last particle" (Score:5, Funny)
Although the parent is rated 'funny' currently, I can only imagine a new, really big lake in Switzerland soon, Lake Hadron.
Re:Famous "last particle" (Score:4, Funny)
Although the parent is rated 'funny' currently, I can only imagine a new, really big lake in Switzerland soon, Lake Hadron.
Re: (Score:3, Interesting)
Obviously only Ubuntu fans would get that. I don't really care about the karma.
For Microsofties and Apple fruitcakes, the current Ubuntu release is called Hardy Heron. It was initially to be called Hardy Hadron, but luckily Shuttleworth reads /. and got fed up with the phallic jokes.
Re:Famous "last particle" (Score:4, Funny)
LA has more dirt, by virtue of its size, but in DC the dirt is much more concentrated and causes more harm. But please be careful, I live about 40 miles from DC.
Re:Famous "last particle" (Score:4, Funny)
I wish both of those areas would keep their "dirt" to themselves. The news is bad enough without politicians and hollywood actors.
Layne
Re:Famous "last particle" (Score:4, Funny)
DC - the lobbyees die.
Both are good, but the former is better.
Re:Famous "last particle" (Score:5, Interesting)
What's this Either/Or crap? Just do both.
Fools! (Score:5, Funny)
Don't they see that there used to be MORE neutron stars?
Re:Fools! (Score:4, Insightful)
Re:Fools! (Score:5, Insightful)
I see billions of golf ball size black holes crossing the galaxy, playing Pac-Man "the milky way edition".
Group collision mergers (Score:4, Interesting)
They also haven't accounted for all possible group particle mergers and interactions in the LHC. Unlike nature, in a particle accelerator they have groups of high energy particles moving in close proximity. In nature, we have lone high energy particles. We don't know what we can create in group collision mergers of high energy particles and even though these are rare compared with single particle interactions, they can still occur. Even if a black hole like particle was briefly formed and then hit by another particle or two or twenty, then what?. The point is, we simply don't know whats possible, but its very likely to be a different situation than simply a lone particle able to break down. If a group collision merger occured in nature, it would most likely be very rarely occuring, but it could be enough to help account for some fraction of the mass of the universe. We simply don't know, but we do know that in a particle accelerator, its going to happen a lot more often than in nature and we don't know what kinds of reactions group high energy mergers could cause.
While its (mostly) safe to assume single high energy particles are not going to be a problem, as they happen relatively often in nature, we cannot say the same for multiple collsion mergers and all possible interactions of multiple particles, as we simply do not know for sure. The current various theories are not proof its safe and the fact we cannot account for so much energy and mass in the universe is a very good reason to suspect our theories are wrong.
Also the fact they are building the LHC is proof in itself that they build it to learn, so they don't currently know for sure. Also for all their planning, even that magnet failure showed their theories and multi-million dollar design plans about how the machine should function can still go wrong. Humans make mistakes. Thats fine, we all accept that, but making a mistake with the LHC could potentially be the most serious mistake in human history.
What concerns me is their intense desire to learn is going to bias their judgment. (I know my desire to learn has biased my judgment from time to time), but this is the most important experiment in human history, so its vital it doesn't go wrong in any way, or it could be the last experiment.
Re:Group collision mergers (Score:5, Insightful)
> Even if a black hole like particle was briefly formed and then hit by another particle
> or two or twenty, then what?
Then you would have a slightly larger nano-blackhole. It would still have such a tiny collision cross-section that it could orbit inside the Earth for a billion years without growing to perceptible size.
But the event you postulate is extremely improbable in any case because of that tiny collision cross-section.
Re:Group collision mergers (Score:4, Informative)
The OP isn't talking about the nano black-hole being miles above the surface of the Earth.
The nano black-hole is so small it will orbit the center of the Earth from within the Earth. It's so tiny that it will simply miss most of the matter in the Earth. Keep in mind that the vast majority of "solid" matter is empty space.
Re:Fools! (Score:5, Informative)
Cosmic rays travel through the Universe with enough energies to boil a cup of water (in one single proton). That's up to 100 000 000 times more energy than the LHC. Those particles collide with everything, at a rate of a few per square kilometer per millenium. It might seem small, but consider the size and lifetime of the Earth, the Moon, the Sun, etc; combined. Particles whose interactions with the atmosphere would have the same energy as the LHC's collisions hit us more than 100 times per day per square kilometer. Over the lifetime of the Earth, every event that can happen in 10 years of LHC operation would already have happened hundreds of thousands of times [arxiv.org] on the Earth alone. Since we're here, there's clearly no need to worry.
Re: (Score:3, Informative)
You're right within several orders of magnitude (sort of). The "ultra-high energy" cosmic rays have, perhaps, 50 - 200 J of energy. To raise a cup of water by _one_Kelvin_ takes nearly 1000 J. So we're off by a factor of 5 right there. To actually boil the water takes many, many times this amount of energy (raise its temperature by 100 K, and then pump enough energy in to actually effect the phase change, at least at STP). Even without taking into account the latent heat of the water, already we're off by 3
Re: (Score:3, Informative)
Re:Fools! (Score:5, Informative)
black holes emit nothing.
Ha!
http://en.wikipedia.org/wiki/Hawking_radiation [wikipedia.org]
Re:Fools! (Score:5, Funny)
Has anyone mentioned that black holes emit Hawking radiation yet? Cause I'd like to clear that up, in case no one else caught that.
Re:Fools! (Score:5, Informative)
Re: (Score:3, Informative)
Even still, they don't precisely emit Hawking Radiation either, but rather that its origin is just beyond the event horizon.
A Little Optomistic (Score:3, Funny)
Dr Farnsworth suggests that you collect your most prized possessions and carry them down to the lowest basement you can find. This way you will at lest be among the last survivors on our doomed planet.
Re:A Little Optomistic (Score:4, Funny)
That's why "The Geeks shall inherit the Earth".....they already occupy all of the basements.....
Layne
Hang on a minute (Score:5, Funny)
Even if they did manage to destroy the world, we'd all die so quickly there wouldn't be time to dish out any blame.
I can imagine the last words in the lab just before we all disappear into a singularity:
"Oops"
Re:Hang on a minute (Score:5, Funny)
Or "I'm hungry" or "This coffee is awful".
Re:Hang on a minute (Score:5, Funny)
Or 'Hey, watch this'
*cue redneck throwing a firecracker into the path of the particle stream*
Cheers.
Re: (Score:3, Insightful)
CERN Coffee (Score:5, Informative)
You obviously haven't tasted CERN coffee - they have expresso machines and its generally very good. Much more likely is "This food is offal". I remember several times going to to the coop and the three dishes of the day were things like calf's head, tripe sausage and tongue...yummmm!
Re:Hang on a minute (Score:5, Funny)
"Oops"
No, the world will end with a scientist uttering "Oh, sweet!"
Re: (Score:3, Funny)
Re: (Score:3, Funny)
Re: (Score:3, Insightful)
Based on airplane cockpit recorders (the black boxes) the most likely last word will be "SHIT!".
Re: (Score:3, Funny)
I have always expected the end of the world to be preceeded by:
"Good news everyone!"
Re:Hang on a minute (Score:5, Insightful)
Re:Hang on a minute (Score:5, Interesting)
Actually we wouldn't. The black hole would not be any heavier than the earth (the moon would continue to orbit it as if nothing had happened, and the black hole would happily circle around the sun). Since the earth's mass is not that impressive, the black hole would have to be tiny, so the area around it where the gravity would significantly bend the universe would also be quite small, making our painful (but swift) deaths rather unspectacular.
Yeah I know. 'WOOOOSH!'
Re:Hang on a minute (Score:4, Insightful)
Exactly, and as minor black holes are used to anchor the Intergalactic superhighways road system in place, I suspect that Arthur Dent is at this moment contemplating the life of a fly somewhere in Kent.
Are there any marine biologists among us? Have the fish been acting funny lately?
Re:Hang on a minute (Score:5, Funny)
You know, it's funny. I was at the aquarium yesterday and for the finale of the dolphin show a dolphin did a double backwards somersault through a hoop whilst whistling the 'Star Spangled Banner.'
we are completely safe, thanks to me (Score:5, Funny)
I'm sorry, but you're completely forgetting about at least one mitigating factor. There's simply no way the earth can be destroyed, one side effect of which would be my untimely demise. Why? Because I've still got a balance on my Capital One visa card, and they will do anything, including changing the very fabric of space and time, in order to not miss out on that interest money. So, we're safe for a while yet.
Re:Hang on a minute (Score:5, Informative)
Whatever small compass we shove the matter into, it'll have exactly the same amount of gravity before and after. If we happen to shove it into a tight enough space that it becomes a black hole, it will be spectacularly tiny. It'll only start to accrete matter as it interacts with it. And, it'll have to get close enough to do it.
Gravity being what it is, it seems far more likely that a black hole formed in the lab would get drawn to the Earth's center of gravity (just like everything else on Earth is) rather than causing the Earth's center of gravity to shift. Shifting the Earth's center of gravity dramatically toward the LHC would take way more energy than what we're putting into the particles at the LHC.
Re:Hang on a minute (Score:5, Interesting)
It doesn't matter where the black hole is created. It, like all black holes, is infinitesmal in size and infinitely dense. It'll fall right to the center of the Earth as if all the matter in between wasn't even there. Also, having started out life with the mass of a few atoms, it's going to take a looooooooooong time for it to destroy the planet. Black holes don't "suck" matter in. They can only pull matter in with the force of their own gravity--which is going to be very very tiny.
It certainly won't shift the Earth's center of gravity appreciably.
Re: (Score:3, Informative)
Yes. It would orbit the the center of mass of the Earth, inside the Earth. Every once in a while it would collide with a particle, absorbing it and acquiring the mass, momentum, and charge of the particle. As a result its orbit would shrink over time. In a few billion years it would settle to the center of the Earth.
Re: (Score:3, Interesting)
Wouldn't it evaporate quickly, as small black holes are want to do? How do we know that it would even have a chance to absorb a particle before it fizzes away?
Re: (Score:3, Informative)
Depends on the model. One of the more popular theories holds that the heart of a black hole is a singularity--a hole in spacetime infinitely small and infinitely dense
Re: (Score:3, Informative)
The problem with black holes having non-infinite density is as follows: forces cause interaction between particles by having them exchange virtual gauge particles. These gauge particles move at most at the speed of light, just like everything else. Howev
Re:Hang on a minute (Score:5, Informative)
Doubt away...
The Black Hole would be a very tiny mass at creation, so small that the difference between where the earth's center of mass was before and is after is insignificant.
(In effect the before state is equal to finding the gravitational center of the earth, minus the gravitational center of a bunch of electrons that are about to power the LHC, then finding the separate center of those electrons poured into the LHC, and comparing that to the after state - where we have to find the gravitational center of the rest of the earth, and the gravitational center of the mini black hole) The center of the rest of the earth doesn't change significantly in the before and after pictures, and the power put into the LHC wasn't enough to cause any noticible wobble before it was used, was it? So it's not going to cause a wobble afterwards.
Now, assuming a stable black hole, it is drawn towards the center of the earth by gravity. Repulsion by solid matter isn't enough to stop it. (Repulsion is an electromagnetic effect - the cloud of electrons around normal nuclei push and so keep matter from passing through other matter. The hole doesn't have a cloud of electrons, so it falls. It 'wants' to go into a narrow elliptical orbit around the earth's core. (It's not falling straight towards the core, because the spot where it formed on the earth's surface has sideways velocity from the earth's rotation). As the hole falls it eats stuff, but that means it also emits electromagnetic radiation as stuff falls in. This works out in the end as a kind of friction, so the hole slows in its orbit and spirals inward. By the time it is up to a few milligrams weight, it is in a tight little orbit around the earth's core, and we are all alive, waiting for it to gradually gain weight. (If the boffins have told us). This takes a year or so, with us not really noticing anything until the hole weighs kilotonnes, at which point the last twelve hours or thereabouts get very impressive and the earth goes bye-bye.
So yes, you end up with the moon peacefully orbiting the black hole as the hole orbits the sun, in orbits that are so close to the existing ones it would be a real challenge to find the differences.
Now, the side of the moon towards us got some interesting radiation exposures during the final few minutes, perhaps enough to melt crater walls and such. The effect of all that light from the final flash might conceivably be measurable, out in the 20th decimal place or so when someone measures the Moon's rotational velocity.
Fortunately, this is all based on the idea that a black hole barely bigger than a proton is somehow stable, which we doubt very much.
A few corrections (Score:3, Informative)
minus the gravitational center of a bunch of electrons that are about to power the LHC
The LHC collides protons, not electrons.
Repulsion by solid matter isn't enough to stop it.
This depends on whether or not it is a charged black hole. In all likelihood it will be since it would have been produced by colliding two protons. Since EM interactions are many, many orders of magnitude above gravitational ones (calculate the difference in the gravitational vs. electric forces in an atom for an excellent illustration) I would expect a charged black hole to interact via EM far more strongly than by gravity.
Re: (Score:3, Informative)
The formula for the lifetime of a black hole is t = 8.4 x 10^-17 * M^3, where M is in kilograms and t is in seconds; as the mass decreases, the lifetime decreases very rapidly. A 1000kg black hole will have a lifetime about equal to the mass of the universe. A 1kg black hole has a lifetime of 10 attoseconds.
Of course, during that 10 attoseconds, the entire mass of the blac
Re:Hang on a minute (Score:4, Insightful)
Since the hole would be created from Earth's mass on Earth, the difference would not be insignificant but exactly zero.
Re:Hang on a minute (Score:5, Interesting)
Actually, it will take a while. The event horizon of the hole will be small; the interaction cross-section with ordinary matter in the Earth is tiny. So it will orbit the centre of the Earth, absorbing a few atoms on each pass, gradually increasing in mass.
We'll notice by the time it reaches the mass of, say, a decent-sized mountain. It will cause local tides. Volcanism. Earthquakes. We won't die of spaghettification; we'll die because something awful inside the earth is whipping up the mantle like a blancmange and shredding the whole crust.
If he's wrong? (Score:5, Funny)
Re:If he's wrong? (Score:5, Funny)
This article doesn't take everything into account (Score:5, Funny)
Re:This article doesn't take everything into accou (Score:5, Funny)
We will just sent sg1 in to take care of the aliens and then we just blame it on the homer simpson type people working there.
Re:This article doesn't take everything into accou (Score:5, Funny)
Now, now, if you follow standard insertion procedure, everything will be fine. ... Although I will admit that the possibility of a resonance cascade scenario is extremely unlikely.
Re:This article doesn't take everything into accou (Score:4, Funny)
I never thought I'd see a resonance cascade, let alone create one.
Re:This article doesn't take everything into accou (Score:5, Funny)
Slashdot doesn't need to hear all this, they're highly trained professionals. We've assured the administrator that *nothing will go wrong*.
Crazy theories (Score:3, Interesting)
My favorite crazy LHC theory is explained in glorious detail in this video [youtube.com]. The guy seems reasonable to start, but he manages to pull in more kook-memes than you'd think possible. Delicious!
Black holes vs. negative strangelets ? (Score:5, Interesting)
Wasn't the actual "danger" in question the creation of stable negative strangelets (which would gobble up regular matter through electrostatic attraction, not through gravity like a black hole) ?
But still, if there was such a thing, cosmic rays would have created one "naturally" by now.
Re:Black holes vs. negative strangelets ? (Score:5, Insightful)
Re:Black holes vs. negative strangelets ? (Score:5, Funny)
Re:Black holes vs. negative strangelets ? (Score:5, Funny)
The Tremendous Hadron Collider is more likely to create a black hole with the munchies.
Naturally occurring high energy particles (Score:3, Informative)
Way lower, here, can be as much as a factor of ten million.
Here's a nerdy but popular account of an extreme high energy cosmic ray detected at the Fly's Eye II [fourmilab.ch]. And that's just what we've detected in a few decades of running small detectors. What the planet has intercepted in the last few billion years must be even more staggering.
Re:Black holes vs. negative strangelets ? (Score:5, Funny)
Yes, but this can be counteracted via the usage of normalets, which are generated by anybody who doesn't read slashdot.
Re: (Score:3, Interesting)
But still, if there was such a thing, cosmic rays would have created one "naturally" by now.
Okay, so it sounds like the theory is that you could create a microscopic black hole that would immediately sink to the center of the earth and orbit there, very slowly accreting matter. But we argue against the possibility saying "cosmic rays would already have created them". Is it possible that they already have and that mini black holes are milling about the earth's center as we speak? Hmm, we have had a lot of earthquakes lately ...
Been there, done that. (Score:3, Insightful)
I wouldn't worry really. If it does destroy the world (which this is saying it won't, because if it could, it would have already happened naturally), then too bad. There isn't anything we can do, and such is life. C'est la vie.
Oh yeah, and I really have been there, there was an open day a couple of months back, the thing is less then about 15 cm in most places (then you have the various vacuum thingys, etc.). Which is rather big, actually, considering the size of the particles...
But but but... (Score:5, Insightful)
"Science is the work of the devil!"
I believe the saying goes, don't let the facts get in the way of a good story. "Safe" doesn't sell National Geographic, let alone Wired.
"cosmic rays" argument is bogus (Score:4, Interesting)
Let me be quite clear that I don't think the LHC is likely to destroy the Earth.
However, the argument that what the LHC does is equivalent to collisions of cosmic rays with the atmosphere is bogus. The LHC's collisions between two particle streams with equal and opposite momentum could create things that are more or less at rest with respect to the Earth; a cosmic ray hitting the atmosphere carries momentum that will cause any resultant particles to move away from us very quickly.
Re:"cosmic rays" argument is bogus (Score:4, Interesting)
I think it's pretty unlikely that two particles are going to hit each other 100% square on and all that energy will somehow cancel out and the result will just dead stop and drop to the floor. The particles in the LHC are going to be colliding with so much energy that the results are most certainly going to be moving at a very high rate of speed, high enough that something like the Earth's gravity will hardly be noticeable to it.
Re:"cosmic rays" argument is bogus (Score:4, Informative)
Hence the argument concerning neutron stars which would stop such a particle.
When news makers will understand? (Score:5, Insightful)
Ha. (Score:3, Funny)
The world will not end when I flip this switch.
I shall prove this, by ...
What in the world could that be?!
*points over there*
*flips switch*
Stopped black hole? (Score:4, Interesting)
Re:Stopped black hole? (Score:4, Funny)
If the black hole has "stopped" it has noticed your presence. At this point, your JuJanta 2000 Peril-Sensitive sunglasses will suddenly go completely black, fully preparing you for the event horizon experience.
JuJanta also recommends its products for the Event Horizon experience, which properly speaking should never be experienced by anyone whatsoever.
Re: (Score:3, Informative)
astrophysics buffs, please correct this if I'm wrong, I'm only an amateur.
My question (Score:5, Funny)
What a way to go (Score:3, Funny)
So each being equally small in probability the two ways the LHC will get us is either by
1. Black Holes (like the article says)
or
2. Instantaneous conversion of all stuff on earth into exotic matter.
Personally #2 sounds more fun.
Review of the Safety of LHC Collisions (Score:5, Informative)
Why Is It (Score:5, Interesting)
Why is it that physicists on and in favor of this project (and those that are following this story) are even remotely surprised by the "Create a black hole, and destroy the world" rhetoric?
We've heard all the sensational "Black holes are the ultimate destructive force" commentary from Astronomers for decades seen all the cool Black hole animations, etceteras, ad nausium.
In my opinion, all the sensationalism surrounding the Black holes to start with was a ploy for funding. Now that same story line shows it's dark side, and people seemed surprised at the outcry and at overly dramatic fear of the LHC.
I'm not saying that sensationalizing science is a bad thing per se, just that people shouldn't be surprised when it bites them on the ass.
Worst case scenario? (Score:3, Interesting)
So, what is the worst case scenario, and, would I notice it?
Black Holes as a power source? (Score:3, Interesting)
Please don't tell me what I'm thinking of is a ZPM, damn stargate Deus Ex machina devices...
Bottom line (Score:4, Informative)
- Energy of maximum LHC collision: 14 TeV
- Energy of "Oh My God Particle" cosmic ray that hit the sky over Utah in 1991: 300,000,000 TeV
Sources:In comparison (Score:3, Insightful)
All things told, I'd rather die by act of science than by act of war.
Hellboy? (Score:3, Insightful)
Let's put it this way:
We KNOW enough about the math, even with all the estimations and incomplete theories, to be able to say that, on the extreme outside chance the LHC does make a mini black hole, the mini black hole will evaporate/destroy itself in a time frame measured in tiny fractions of a second. It cannot destroy the Earth, let alone the solar system or the galaxy.
On the other hand, know nothing of the possibilities of interdimensional travel. Therefore, we are safer considering, and maybe preparing for, the possibility of Hellboy landing in the lab. And he ain't such a bad guy, really.
Possibly explanation for another question? (Score:4, Funny)
Why are we finding no extraterrestrial civilizations?
They all get to this step in technological advancement and "Black Hole" themselves?
Maybe a significant portion of existing black holes are not the results of collapsed stars, but rather previous Hadron-like mistakes of monumental proportions?
Re:Huh? (Score:5, Funny)
"In theory", posting to Slashdot is safe.
"In theory" you can't accidentally summon the elder gods by not limiting your .signature to 120 characters.
"In theory" posting more than twice within a ten minute limit won't create an imbalance of left-handed and right-handed electrons within the local ethernet causing anything up to and including total protonic reversal. (I bet you'd be kicking yourself for not buying cables with signal directional markings [slashdot.org] which could have prevented this problem.)
So, yes, "in theory" the world is safe from being destroyed by you. Today.
And "in theory" that makes me feel better.
Re:Huh? (Score:5, Insightful)
Yes, in theory. Just as the sun will rise tomorrow "in theory." And if I repeatedly shoot someone in the head, they will die, "in theory." And reality exists, "in theory."
Provability only exists in mathematics. For everything else, from decisions about what to buy at the supermarket, to designs of scientific experiments, we humans must use mental models that rely upon fundamental assumptions about how the universe operates (e.g. that past experiences allow us to make meaningful predictions). In other words, every action we take must be informed by some sort of "theory." The question then becomes "how robust is this model/theory?", "how much can I trust the predictions?", "what is the range of the possible outcomes?", "what are the consequences of errors in the assumptions/model/theory?", and so on.
If you have a specific problem with one of the assumptions, logic, modeling, mathematics, data acquisition, or analysis, then point it out in detail. But saying, "that's just a theory" is not useful. Everything we do is based on theories.
After all, the opposite is also a theory: Not turning on the LHC won't cause the destruction of the Earth... in theory.
Re: (Score:3, Funny)
Experiments are conducted based on our lack of confidence in those theories. Either this theory is trustworthy enough to make the whole experiment pointless, or it's not trustworthy and experiments are justified. You can't have it both ways, and anyone who attempts to
Re: (Score:3, Insightful)
Re:Huh? (Score:4, Insightful)
Bull. We don't know exactly what will happen, but that's not the same as having no idea at all. We know very well that certain things will not happen; like destroying the earth. The experiment to be performed is performed regularly by random cosmic rays in the atmosphere. We don't know what will happen in terms of the data collected by the sophisticated instruments in place at the LHC, because these instruments are not in place for those naturally occurring experiments. But for those naturally occurring experiments, certain very crude instruments are in place. Including a crude, but actually perfect detector for earth-destroying effects, which we call the earth. It's still here.
Re:Huh? (Score:5, Insightful)
There are two opposing viewpoints on the matter.
On the one hand, we have particle physicists whose "theories" on the interaction of subatomic-scale matter is drawn from decades of research and experimentation.
On the other hand, we have people who know essentially no physics and seemingly assume that the people building the LHC must be as lost when it comes to science as they. They make the argument, "Well, we don't *really* know what's going to happen."
It's amazing that the latter are able to function, as crippled as they should be of the fear of uncertainty.
Re:Huh? (Score:4, Informative)
Re: (Score:3, Informative)
Re: (Score:3, Insightful)
Logic can never be better than the assumptions it works with. Garbage in => garbage out.
Logic is a way of saying that anything which didn't happen yesterday won't happen tomorrow
No, logic nothing to say about that - it only concerns the way in which we manipulate logical statements. What you are talking about is empiricism - the idea that because something has always happened before, it will happen again next time; this is a useful notion in many sciences, but there is no logical reason why it should be valid.
Re: (Score:3, Informative)
Glory Road [wikiquote.org] by Robert A. Heinlein [wikipedia.org]
Re: (Score:3, Insightful)
It's kind of like "Holy crap if the Sun collapsed into a black hole all the planets would be sucked in". If the Sun spontaneously collapsed and was a black hole, which theoretically can
Re:Do I have this Right? (Score:5, Informative)
Right? I'm not a physicist.
In short, you are correct. If you were to magically replace our Sun with a black hole of 1 solar mass, the gravitational pull would not change. There would be a whole lot of other stuff going on, but black holes don't magically increase the gravitational pull of a mass.
If I made a blackhole out of the amount of mass that the LHC is accelerating, and put it suspended in a sealed jar on my desk, I would only feel the gravitational pull of the mass that actually is the black hole. So, unless people are having difficulty with the gravitational pull of things on their desk, I wouldn't be too worried about it.
How small are we talking about? (Score:5, Interesting)
Well, exactly how small black holes _are_ we talking about? Because it seems to me that the whole scare is due to a few people's not really understanding physics.
Gravity is actually the weakest force at a particle level. But ok, let's imagine a really really small gravity well.
Arguably the interesting thing about one would be, basically, "up to what distance can it gobble things up." In other words, the the Schwarzschild radius [wikipedia.org].
I'll use simplified version, which is: 3km for something weighing as much as our Sun, and it varies linearly with mass from there. Literally. For Something the size of Earth it would be 9mm, btw, but they won't collide particles weighing the same as _Earth_ there. If they did, I'd worry about _recoil_ before I worry about black holes.
So how big a black hole will they create there? Say, about the weight of two neutrons? _Three_ neutrons? Heck, let's be generous and smash a whole five neutrons together. Each neutron weighs 1.67492729x10^27 kg. So 5 of them is very approximately 8x10^-27 kg. The Sun weighs 1.9891×10^30 kg, let's say 2x10^30 kg.
So we get roughly 3km times 4x10^-57 km, or 4x10^-54 metres. That's the ridiculously infinitesimal size, up to which it could gobble matter. By comparison a helium atom has a radius of 31 picometres, or approx 3x10^-11 metres. Our black hole is about 10 to the 43'th power smaller than that. Write a zero, a dot, 42 more zeroes and a 1. That's how much smaller that black hole is than a helium atom.
To be absorbed by it, another particle would have to come that close to it, overcoming all other forces. Which become pretty damn strong when you try to get that close.
In effect, the _only_ way for that "black hole" to gobble any other particle, is for that other particle to be shot directly at it with an even bigger particle accelerator. With some incredible (and thanks to that guy Heisenberg, also pretty much impossible) accuracy. Otherwise, it will be bounced around by the other atoms, without ever getting close enough to one to actually absorb one and get bigger and meaner.
If that's the big threat to Earth, well, I've seen scarier kittens than that ;)
Re:Broken link (Score:5, Funny)
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---I'm a physicist (working on my PhD), but I've had one nagging question about hawking radiation noone's been able to answer (satisfactorially)
I'm a lowly EE student :) I think I understand though.
---So, the process of hawking radiation can be thought of as a particle/anti-particle pair being created near the event horizon. Suppose that one of them is juusssttt close enough to the event horizon that it falls in and the other one remains outside. We assume that (to conserve total energy) the antiparticle fa