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Investigating Artificial Black Holes
Robber Baron writes "I remember years ago watching a cartoon in which an inventor had managed to create 'portable holes.' Now along those lines, according to this story in the Christian Science Monitor, scientists are on the threshhold of developing the 'do-it-yourself black hole' (Well, no, it's not quite do-it yourself as you need a pretty large collider to pull it off.) They're hoping to use the new Large Hadron Collider at the European Center for Nuclear Research to create many tiny black holes and observe the Hawking Effect as they dissipate. Keep your shotgun handy though, as they are more than likely going to open up a portal into another dimension and all sorts of nasties are going to come pouring out."
I remember years ago watching a cartoon in which an inventor had managed to create 'portable holes.
That was Wile E. Coyote in the Roadrunner, first introduced in the 1952 cartoon "Beep Beep".
I think the Acme corporation has the patent on them, along with Jet powered Roller Skates, Coyote-sized Slingshots, Dehydrated Boulders, Do-It-Yourself Tornadoes, spring-loaded Boxing Gloves, dropping Anvils from Tightropes, Jet-propelled Pogo sticks and Unicycles, and Fake Railroad Crossings.
Just very short'n'simple - even such a massive accelator and/or collidator doesn't gain so much energy as most of the cosmic radiation rays. So - everything you can simulate there happens every day on the whole planet (but because you can't predict when and where you are unable to study it)
A very small (Planck-scale) black hole evaporates too quickly for that to happen.
The reference to the Hawkings Effect is the key. Steve H. has a well accepted theory that black holes leak. The smaller they are the faster they leak. (It's basically a quantum effect, if the black hole is low enough mass the singularity is close enough to the event horizon to let some matter tunnel out and escape. The event horizon shrinks further until the black hole evaporates.) If all goes right the holes we could create with our limited technology couldn't last long enough to cause any problems. This of course is all just theory, if he's wrong there will be hell to pay.
I'm an American. I love this country and the freedoms that we used to have.
Despite it's name, and the fact that it is, indeed, owned by Christian Scientists, the Christian Science Monitor is actually considered a reputable paper (scroll down for CSM), with high-quality journalism. It has a more centrist or even liberal bent, not Christian right.
However you are correct in that we have no idea if Hawking radiation even exists. If it did, we would observe GRBs of a specific type, yet we haven't. I think we should look for these GRBs some more before we start cooking up black holes.
Quid festinatio swallonis est aetherfuga inonusti?
Africus aut Europaeus?
"But wait", I hear you say, "Has anyone considered that creating artificial black holes might not be the best idea?" The idea of creating black holes in the laboratory has to give one pause. I mean, how can anyone resist the urge to imagine future headlines like "Artificial Black Hole Escapes Laboratory, Eats Chicago" or some such thing? In reality, there is no risk posed by creating artificial black holes, at least not in the manner planned with the LHC. The black holes produced at CERN will be millions of times smaller than the nucleus of an atom; too small to swallow much of anything. And they'll only live for a tiny fraction of a second, too short a time to swallow anything around them even if they wanted to. If it makes you feel any more comfortable, we're pretty sure that if the LHC can produce black holes, then so can cosmic rays, high-energy particles that smash into our atmosphere every day. There are probably a few tiny black holes forming and dying far above you right now. So I think we should all relax, fire up the Large Hadron Collider, and get ready for a view of the universe that we've never seen before.
The simple truth is that interstellar distances will not fit into the human imagination
- Douglas Adams
The name of the Christian Science Monitor might lead those unfamiliar with it to think that it is a Christian news publication focused on science. Actually, it is a news organization associated withis a small religious group known as "Christian Science" (offically "The Church of Christ, Scientist"), which has very little in common with Christianity.
Those who would give up essential liberty to purchase a little temporary safety, deserve neither liberty nor safety.
First of all, the idea is that black holes dissipate via Hawking radiation, not blackbody radiation. It's been a few years since I read Hawking's papers on the subject, but they are quite different things. It has something to do with quantum fluctuations and virtual anti-particles being pulled INTO the black hole being the same as normal particls falling OUT of the black hole. That's how I remember it, but read his works, it's explained pretty well.
Second of all, higher energy impacts occur all of the time in space and in the upper atmosphere (which the article points out!) so either 1. Even that much energy is not enough to actually create a micro-black hole, in which case no problem or 2. They evaporate somehow, in which case, no problem.
Finally, these things will have very little mass. A penny does not attract near by mass towards it with any noticable effect, so these won't either. Just because they are very dense does NOT mean they have an immense gravitational field.
Here is a simplified way to look at it while ignoring blackbody and Hawking radiation. A black hole exists because at some point enough matter got together so that its gravitational field counteracted electrostatic, strong nuclear and weak nuclear forces, and it collapsed into a mathematical point. It remains a point because its gravity remains strong enough to counteract these other elementry forces. Now, if the blackhole was created by something else counteracting these forces, such as a high energy impact, then, once it is created, the gravitational field is NOT strong enough to counteract the elementry forces, and the black hole would dissipate.
IANAP
ASCII stupid question, get a stupid ANSI
Second, unstable black holes, of the sort being made here, occur all the time on earth. Cosmic radiation creates them. They are just trying to make one the same way that they occur all over the place so they know where it will be and have recording equipment ready for it.
--
Evan
"$30 for the One True Ring. $10 each additional ring!" -- JRR "Bob" Tolkien
The gravitational attraction between two objects is dependant on mass linearly, but is also dependant on the distance between those two objects.
Gravitational Force = GMm/r^2
Where G is the gravitational constant of this Universe, M is the mass of the larger object, m the mass of the smaller object, and r the is the separation between the center of the two objects. [an objects gravity is "centered" at it's center, thus the gravitational force at the center of the earth is infinite (r = 0)].
It is true that black holes do not create increased distortions of the gravitational field by altering size (initially). They do so by shrinking the radius of the object. If you double the mass of the sun, but keep its radius the same, the gravity you'd feel on the sun's surface would only be doubled. If, however, you half the sun's radius, but leave the mass the same, then the gravity you'd feel on the sun's surface would be quadrupled (because r is 1/2, the denominator in the formula is 1/4).
I believe what you were trying to say is that the effective field of gravitation for these black holes would be so small as to be insignificant, and you're right. Gravity decreases exponentially with an exponent of 2 as the distance between the two objects increases; thus, for black holes of the mass these guys are creating, the field in which they would warp the space-time continuum would probably be atomic -- e.g., after about the radius of an atom, their gravitational force becomes insignificant.
Of course, this is all a shotty analysis of it, as Newton's Laws of gravitation don't even hold true for describing planetary orbits, and even Einstein's Theory of Gravitation (the warping of space-time) breaks down at a singularity.
social sciences can never use experience to verify their statemen
The reference to the Hawkings Effect is the key. Steve H. has a well accepted theory that black holes leak. The smaller they are the faster they leak. (It's basically a quantum effect, if the black hole is low enough mass the singularity is close enough to the event horizon to let some matter tunnel out and escape. The event horizon shrinks further until the black hole evaporates.) If all goes right the holes we could create with our limited technology couldn't last long enough to cause any problems. This of course is all just theory, if he's wrong there will be hell to pay.
First off, IANAQP (I am not a quantum physicist), but, that said, some corrections are in order... first of all black holes do not release matter as they dissipate, they release radiation (according to Dr. Hawking at least). Secondly, if he's wrong there won't be hell to pay, because the same theories that explain what black holes do are the theories that will allow this experiment to occur; in other words, we won't be able to create the black holes if the theories are wrong.
Here's an question- since we put matter into the black hole and get out only radiation as it dissipates (or so the theory goes) could we theoretically create black-hole-driven power plants where we feed matter into black holes and harness the energy as it escapes? Or is the radiation created as the black hole collapses unusable as a source of energy? I suppose it would also depend on the amount of energy used to create the holes. And from a P.R. standpoint, the fact that many people (in the U.S. at least) are still scared of nuclear plants, and apparently even many slashdot readers think that tiny black holes function like ultra-powerful vacuum cleaners, could mean a little trouble getting the local black-hole power plant approved.
By the way, I highly recommend Dr. Hawking's book The Universe In A Nutshell. You can get it here. It's a lot easier to swallow than his previous book, and gets into many of the more interesting theories in science today without involving too much math. Topics covered include black holes, time travel, wormholes, etc.
Not quite. The curvature of space would be almost exactly the same at the orbit of the earth. If the Sun were to become a black hole, the curvature of space (or the gravitational forces at any point in space) would be the same for any point not inside the current surface of the sun.
To explain this a bit, first imagine a spherical cow with uniform density, floating in empty space. As you aproach the cow, the gravitational attraction towards it is proportional to the inverse of the square of the distance to the center of gravity of the cow. The density of the cow doesn't matter. An infinitely dense point-mass cow would cause the same attraction. Now, continue on your path, and you puncture the outside of the cow. At this point, it's easier to figure out the gravitational force as the sum of two force vectors. One force vector is for the sphere of matter "below" you, which is the sphere of matter with its center at the center of gravity of the cow and its radius being your distance from it. That one's easy to figure out, it's just some fraction of the mass of the cow, times your mass, devided by the square of the radius. The harder part to figure out is the force vector of the spherical shell "above" you. this involves some mathematics that I can't recall right now, but trust me, the answer ends up being zero. So, if you graph out the gravitational attraction from infinity to the center of the spherical cow, it will start as an increasing parabolic curve and continue that way until you hit the surface, at which point it will begin to decrease at a cubic rate that ends up equal to zero at the center of the cow. Now, if you collapse the cow into a black hole, the exact same equations hold true, the only difference is that the surface of the cow is now so much closer to the center, that the parabolically increasing rate has much more distance over which to increase.
I hope that made sense. It's late, and I'm going to bed now....
Pound! Bang! Bin! Bash! is this a shell script or a Batman comic?
Not long ago, I attended a symposium where the presenter made a decent case, using some of the same arguments from QM that Hawking used, plus some other bits (sorry, don't have the notes), that Hawking Radiation would actually be forbidden by other physical laws. While the stuff at Ph.D. level and beyond me, it wasn't for the rest of the audience - and they couldn't poke any holes in it right away. Or by the end of the Q and A session.
Is it fringe? Sure. Be nice to verify, though, in the face of what could be a world-ending event. If black holes exist sans Hawking Radiation, we'd be in quite a bit of trouble upon the production of even the smallest one. Probably wise to check that little problem out. I'm not advising doing anything wacky and superparanoid, like building it on the Moon
Scientific method is great, but when it comes to doing planet-wide experiments, you get a sample size of 1 and no control group. Oh, and no "do-overs." This is Chicken Little, signing off.
The article doesn't make clear that this is an extremely speculative prediction which requires some highly nonstandard physics results. Indeed, if this accelerator (or cosmic rays for that matter) actually produces black holes it will undoubtedly be considered one of the greatest and most astounding physics discoveries of the past 100 years.
The paper that started all this speculation (which is now presented as fact more often than not) is http://xxx.lanl.gov/abs/hep-ph/0106219. In that article, the authors explain that the model requires a version of the universe that has ten dimensions, arranged in such a way that the Planck mass, where gravity merges with other forces, is about 10^3 GeV. Standard physics says that the Planck mass is at 10^19 GeV. Their assumption is 16 orders of magnitude different from the conventional wisdom.
The paper above concludes with the comment, "Collider study of black hole creation would certainly be an astounding pursuit". Indeed, the authors and experimentalists would be guaranteed Nobel prizes if black holes actually form.
Unfortunately, popular articles gloss over the speculative nature of these predictions and we are told that the LHC "should be enough" to create black holes, and that cosmic rays are "probably" creating them right now. The levels of certainty implied by this wording could not be more misleading.
Time only stands still as seen from afar. Matter close to and within the black hole continues to experience the advancement of time until it hits the singularity.
As for your notion of a shell, see Susskind's article, Sci. Am. April 1997 p. 52.
You have duplicated part of his argument. Your fog notion is incorrect; the shell, as seen from afar, moves out with more mass accumulated. Susskind then notes that the shell does not appear at all to an observer following matter into the horizon, but that the shell, when approached slowly and not in free fall, becomes apparently very hot. This is a paradox so severe that he calls it "black hole complementarity".
But, complementarity, proper, is not a paradox but a deep mathematical property of physics. Wave-particle duality is more like this problem. And, Susskind's reasoning is partially suspect because his picture does not uphold the equivalence principle (that the rules of physics are locally the same everywhere in spite of various speeds, accelerations, and gravitational fields). Using equivalence, the slowly lowered observer would see the shell sunk farther into the black hole than a farther observer would see, and the two would disagree on the corrected temperature and time of existence of the shell. The two observers would accuse each other of being subject to an illusion.
--
Mike Burns "Nothing unphysical can be a physical cause."
Michael J. Burns
Many people have already pointed out that black holes are not going to destroy the earth, but I guess people might be interested in this, which is a simulation of what a black hole event might look like. It shows an end-on view of the the ATLAS detector (picture), with most of the noise and rubbish taken out.
The curved, coloured lines are tracks left by charged particles. The green ring is the electromagnetic calorimeter, whilst the red ring is the hadronic calorimeter. Calorimeters just measure energy - so the histograms radiating out show how much energy was deposited at each point. So by looking at the histograms you can get an idea of how energetic the track was. Hope that makes sense!
Incidentally, the picture is zoomed to show the interesting detail better. The detector is extremely large! Look here for a picture that shows people standing next to it