Slashdot Mirror
Optical Black Holes in the Lab
spaceorb writes "According to researchers ... it may be possible to create black holes by creating a vortex of fluid that swirls at velocities comparable to the speed of light. Follow the above link for the theoretical discussion or here for the story on unisci.com." These are optical analogues of black holes, not really gravity wells, but they may advance our understanding of the real thing.
Instant optical computers?
Optical Linux!
Optical beowulfs! 8-)
Who gives a shit?
People are starving, crime is running high, wars abound and these people are discovering black holes!!????!
Sheesh, how perverse can people be?
Fuck you
32423
you want realdoll.com
I hate trolls!
I don't know
Actually I believe this story was already in New Scientist last summer. I can actually understand that article, unlike this one, although I guess it's out of date. It's certainly an incredible idea.
Too right. It's like that accelerator in NYS that was worried about making a black hole by colliding super powerful particles.
Summary: if the containment fails, we're all dead in 30 minutes.
and on that cheerful note, shall we all move unto the smoking room...?
Jeez, did you even bother reading the article? Or is this flamebait? Either way, you're still lame.
The related article in cnn yesterday gave a little more information.
Too true
Hmm... If she is naked woldn't that preclude her wearing pants ?
The text shows that these only trap light by chemical means in order to simulate a black hole, there is no actual gravity well produced :)
Are you a scientist? Do you know what the fuck you're talking about?
I didn't think so.
Move along, now.
This fool has never positioned his black hole over a South American toilet. If he had he would have observed that the vortex in fact DOES rotate in the opposite direction. Perhaps his TAX funded grant wouldn't spring for a plane ticket across the equator for him to verify that the "myth" is indeed true, as anyone who lives near the equator knows. The Coriolis effect can be observed at as little as 100 feet north or south of the equator. (Doesn't this guy watch PBS?) The rest of his article looks like a marvelous way for him to spend a lot of Tax money while proving little or nothing.
The idea is the rotate some fluid extremely fast (reaching the speed of light). Assuming that an actual experiment wouldn't be bigger than say 10 cm, this would give for a particle in the fluid an acelleration of 1/2 v^2/r = 1.8 10^18 m/s^2. I don't think any 'fluid' can exist at such acceleration. It also seems impossible to keep the fluid together because of the centrifugal forces.
The acceleration should of course the calculated with general relativity, but the idea remains the same.
bye,
AC
There's no way such a thing tunrs into a gravity well (or REAL back hole).
I don't understand how this gets a score of 2: read the link to the actual article, or refresh your memory to freshman physics. Light travels at a constant speed in a vacuum. It travels at a reduced speed through a medium, because of initeractions with the atoms. There are substances in which light moves very slowly. You may have heard of something called cherenkov (sp?) radiation, which is a really cool looking optical version of a sonic boom, that occurs when you shoot a particle through a medium, faster than the speed of light in that medium.
copper doesn't conduct light (ever try looking through a window made of copper? it's hard), it does conduct electricity. the speed of light in optical fibre however is 2e8 m/s
I wear photon threaded underpants. Will I loose them? I am afraid.....very afraid
Sheesh - for a startoff its a *optical* black hole, it has no gravity well. Did you actually read the article ?
I assume these scientists have some plan for containing these black holes that they're planning on making
Give them a charge and keep them in a magnetic bottle. Simple. Assuming they where making them, which they are not.
Even if we created a real black hole, hawking radiation causes them to evaporate instantly. You'd need a continent sized mass to last more than a few seconds.
I can only assume that the black holes they make would sink to the center of the Earth and destroy the planet. I'm not sure what the figures are on this, but seem to recall 30 minutes as a back-of-the-envelope estimate.
And even if they didn't evaporate, the black holes we could create would be smaller than an atom. They could happily orbit inside the earth for millenia, only gobbling a few atoms a year. Where did you get that half hour figure - I presume your imagination.
The casual ignorance of slashdot readers on basic science astounds me at times.
There is however a valid critisicm to be made here: Scientists are sometime guilty of phrasing their findings in as tittilating (sp?) a way possible, because it means people pay more attention to their results, and increases their chances of getting funding. The black hole analogy, while useful within circles of physicists (perhaps) is a sad one becasue you just know it's going to get all the pop science magazines excited, and elicit all sorts of responses like the ones we've seen here. Black holes in the lab, pfft. We live in a sound byte world. We all(including physicists) need to be careful what kind of sound bytes we offer the masses... they could backfire The one that pissed me off the most was the web site by the IBM researchers working on "quantum teleportation". I thought their speculation was well on the side of irresponsible reporting of results that Feynman complained about.
When speaking of velocity Example: If we send something from the earth, the velocity can be like 100 miles per hour, but compared too the sun, it might only be like 50 miles per hour depending on the direction we sent the object... The same with light.... wget
Sheesh - for a startoff its a *optical* black hole, it has no gravity well. Did you actually read the article ?
I assume these scientists have some plan for containing these black holes that they're planning on making
Give them a charge and keep them in a magnetic bottle. Simple. Assuming they where making them, which they are not.
Even if we created a real black hole, hawking radiation causes them to evaporate instantly. You'd need a continent sized mass to last more than a few seconds.
I can only assume that the black holes they make would sink to the center of the Earth and destroy the planet. I'm not sure what the figures are on this, but seem to recall 30 minutes as a back-of-the-envelope estimate.
And even if they didn't evaporate, the black holes we could create would be smaller than an atom. They could happily orbit inside the earth for millenia, only gobbling a few atoms a year. Where did you get that half hour figure - I presume your imagination.
Sigh, the casual ignorance of slashdot readers on basic science astounds me at times.
When speaking of velocity Example: If we send something from the earth, the velocity can be like 100 miles per hour, but compared too the sun, it might only be like 50 miles per hour depending on the direction we sent the object... The same with light, it's all depending of what object you compare it with. wget
That's why it's so cool!
(But, if you insist, she doesn't have to be wearing the pants, the grits just have to get poured down them.)
Certifiable bullshit? I think not. Welcome to the universe, jerky. This further blurs the distinction between what is and what is not. *chuckle* If this experiment is proves correct, you're *really* not gonna like what comes next. Interstellar c could be *way* faster than what we see here in our mass filled solar system.
Yep, Black holes can have both a spin and a charge; See also Kerr-Newman Black holes or kernels - just imageing what a great method of storing energy a black hole could provide: just spin it up electromagnetically or get the energy back out by slowing it down.
Certifiable bullshit? I think not. Welcome to the universe, jerky. This further blurs the distinction between what is and what is not. *chuckle* If this experiment is proves correct, you're *really* not gonna like what comes next. Interstellar c could be *way* faster than what we see here in our mass filled solar system. This article, and the comments I've read on it so far, are total bulls**t. Even my female collie could write a better article!!!
I think I got you beat here...
:-)
4 gig drive...Win95/WinNT/Linux (.5/1.5/2 GB partitions)
and ~1 GB of mp3s under Linux
http://www.rowland.org/atomcool/
If the fluid were spinning fast enough there would be a vacuum in the middle....
Actually, don't particles actually make it in? It only appears that they don't to outside observers.
Oops..reread the article. No cavuum in the middle. Still intersting but not so much as I hoped.
How do you think black holes initiated in the first place? I'll tell you how: Aliens did this and it ate there species up and there whole planet and now that's what we look at with the hubble telescope. This is just great!!! I'll be playing on my computer and get sucked through the window because some genious scientist decided to "create a black hole on Earth!" *rolls eyes* Sheesh...
Not a black hole, but a
"Supercooled dielectric light trap"
Far cry from a black hole.
Worst case(but unlikely)scenario is that too
much light gets trapped and turns to some sort
of matter. *boom* goes the lab.
Or the light escape at once as a burst of gamma
rays.
Or..the light slowly trickles back out as the
dielectric warms up.
It's the end of the world...GAAAAGH!!!
*snort*
I imagine the photons would be simply absorbed by the apperatus before anything interesting could happen. If they aren't absorbed *somthings* bound to happen once the thing reaches some saturation point. Laser emission?
i have a big black hole in my pants from which no hot grits can escape. thank you.
You mentioned nuclear weapons. I would LOVE to see this technology used to make weapons! if one could control the black hole (they must be able to do this if they are even contemplating making one) think of the destructive power! China wouldn't dare mess with us with a couple of those babies aimed at 'em!
The A.C. of this article must be as bright as a Black Hole and twice as DENSE.
Cool! Got any url's for that?
An 'aether' theory, OTOH, would fit the bill rather well.
Relativity is an aether theory. QM is slowly accepting the aether but in a roundabout way. "Partical exchange" == gravity. *snicker*
I'm assuming the charge would effect the matter
outside of the EH. You can't have action without
transmission of information
s/\ hole/piece\ of\ paper/g :)
Surround a ship with this photon absorbing shield and no radar waves bounce back, no emitted light. It's a Romulan cloaking device based on an artificial singularity! Kewl!
I wonder... that flash of light that i concur would most likely be emitted... could you use it in a practical sense? in effect a `capacitor' for some high level photon experiments? simply by disrupting the vortex before such a phase change, and by focusing the pattern in which one interupts the vortex, one could create a precise emmission... i wonder about this its intruiging.
But she's not black!
Relativity, neither special nor general, has anything to do with aether theory, a long-disproven holdover from the 1800s.
In Hawking radiation, uncertainty creates the usual particle-antiparticle pair, just outside of the event horizon. One is absorbed, the other lost. Unable to destroy each other, that would violate mass-energy conservation. The universe, disliking unbalanced books, subtracts an appropriate amount of mass, charge, and angular momentum from the black hole. The universe, however, does NOT duplicate the lepton number, baryon number, strangeness, or any of the other numbers associated with particles inside. So, it is not as if a proton disappears from inside the black hole and reappears outside, not at all.
At no point do any particles in a black hole cross the event horizon or leave it. They all plunge into the singularity, a trip which lasts about a tenth of a millisecond per solar mass of the black hole itself. They are therefore not around to be crowded inward as the event horizon shrinks.
Next, it only takes an infinite amount of time for a particle to cross the event horizon from the outside perspective of an observer who is not falling into the hole. To the particle or an astronaut falling into the horizon, the trip is quite short. Therefore, to say that black holes only exist asymptotically is incorrect.
Sheesh. Learn some physics before you go around crying about how the sky's falling. Ignorance is far more dangerous than science.
If you think that any slowdown in the speed of light in a medium is accompanied by a change in time or distance, take a look at glass. Light travels at roughly 66% of its speed in vacuum there. Are you suggesting that the measured thickness of all pieces of glass are off? Are you suggesting that I could slow down time by wrapping myself in glass?
Also, analogies break down, eventually. There is no reason to think that Hawking radiation will occur from something like this. You simply cannot extend the analogy forever.
There is no possiblility of making a black hole at RHIC. If you dig up the old Slashdot article on it, you can probably find links to some sites that explain why it's not dangerous.
It's not sad, the analogy is very direct. These things really do behave exactly like black holes in many respects. You'll note that the original article didn't claim that they were creating real black holes. This work is also important and deserves to be publicized, because it offers the possibility to determine things about real black holes without expensive and difficult computer simulations.
The difference isn't as big as you think; the behavior of light around these things is really like the behavior of light around a real black hole determined by Einstein's equation.
2) This "optical" black hole does not absorb matter. It will not eat the Earth. Read the article.
3) This "optical" black hole does not attract matter. It does not exert a gravitational pull. It will not eat the Earth. Read the article.
4) No, it's not going to go haywire and suck all of the light out of the lightbulbs, either. Read the article.
5) If you had done any research into the strangelets, you'd have realized that there was nothing to be worried about, given that the only thing strangelets would be able to convert, and that only hypothetically, is free neutrons, not those bound in nuclei. Free neutrons are rare. They have a half-life of roughly one thousand seconds. The scare was a non-issue. You must not have read that article, either.
Of course, a black hole doesn't destroy photons when they reach its event horizon; it's the singularity that's the problem.
Do you agree with the sites you quote or not? It is really not clear. You say "unfortunately" before citing "Bad Coriolis" implying you disagree with the statement, but at the end the word "myth" sounds like your referring to the "myth" from your first quote, which the physicists have a problem with. Anyway, I'm prompted to add a comment on how obnoxious the "Bad Coriolis" author is. In the worthy cause of scientific education this guy is contentious and high-handed, which are exactly the wrong characteristics in an educator. In few of his FAQs he is defensive and basically chides his questioners (who may be in grade school or high school) for being stupid or wrong. And about the Coriolis effect, if the rotation in sinks and toilets is due to random disturbances from handwashing and the quirks of plumbing the rotation should be clock-wise around half the time, which I don't think it is. Maybe I should start counting.
It's been a bit scary reading all the "theories" about this that slashdot readers have come up with. Talk about woefully misinformed.
Actually they use the *PREVIEW* button before posting.
Jon Katz will punish you for trolling!!!!!11
The guy posted from a .nl mail address, which is in mainland Europe in case you didn't know, where they use "." and "," oppositely to the English/US/etc convention. He made a mistake (two mistakes) but give him a break.
I bet he understands your culture much better than you do his.
college kid punk.
I'll be right behind ya. all the way. heh.
stop that hole!!
Truth hurts, does not it?
If it's a smoking room, it must be on fire.
Another (scifi) book about this scenario, written by astrophysicist John Wheeler, is the Krone Experiment -- although I don't recommend it. Wheeler is good at physics, bad at writing fiction.
It amuses me that folks refer to primordial (nee quantum) black holes as having larger or smaller singularities than other black holes. A lot like the 'ring-shaped singularity' problem (you'll encounter this when talking with igor n. and penrose and even wheeler about their work, heh), a singularity is a geometric point. Also, a singularity isn't an event horizon. Other folks will grant that the singularity must occupy at least a planckspace worth of volume, but even then, singularities would be the same volume (as-little-as-physically-possible) with a simply positive mass.
I'm not a physicist proper, but let me just say that it runs in the family. And I've got some physicist friends who love to talk about this stuff over drinks.
Cheerio!
-j.m.eddington
The only problem I see is that it would be physically impossible. The best representation of a singularity (from my minimal understanding) is point at which matter ceases to move forward through time. An object that is in the past cannot be affected by objects from the future (beyond the singularity), so causality no longer applies - it would be physically impossible to move regardless of its quantum properties. If you could move the matter in the black hole itself, you destroy any connection between the singularity and the rest of the universe and just end up with a chunk of matter.
Of course, I'm just having a guess, but I really don't think its possible to move a black hole without destroying it. Black holes are supposedly very delicate things.
I think you need to actually read their work. Yes, gravitationally they're not like black holes, but that doesn't mean that the physics isn't analogous. Elsewhere I've mentioned work by Jacobson that does something like this with superfluidity; the solutions are directly analogous to the Kerr solutions in GR. It's not a gravitational effect, but the effects on photons are quite similar.
It doesn't matter that it doesn't obey the equivalence principle; the point is that it acts on light as an effective gravitational field and so they're using light to probe black hole physics. If they used something else then the analogy would break down and it wouldn't be a useful experiment.
Since you apparently didn't read up on Jacobson's work like I suggested, let me cite it again. Yes, you can get effects similar to Hawking radiation without an actual black hole. And if they can do it in a superfluid, I don't think it's beyond conception that it could be done in a Bose-Einstein condensate.
Let us for the moment ignore the fact that you are an idiot for nitpicking on a post that has nothing to do with the article hand... What _is_ important here are orders of magnitude (they are within a few and are getting closer) and that citing numbers in scientific notation in most places outside scientific literature can make one appear out of touch. For example: "I am 1.9 times ten to the 1 years old." "Dinner will be ready in 2 times ten to the negative two hours." "You were driving 1.039 kilometers per 1 times ten to the 0th hour over the speed limit." (if you are a real troll, try 'meter' vs 'metre') Or, in your case: "This is the 1.2 times then to the fifth time I've trolled today." And of course, bearing in mind different notational conventions outside your precious academia in places such as europe, asia, africa, south america, and anywhere else not falling within your sphere of ignorance. So, in closing: May a score of pine cones be applied liberally to your posterior with a dozen footpounds of might.
Hawking radiation isn't limited to fermions. If you want something to back up the article, try looking for publications by the scientists doing this work. They apparently think it can be done.
Something I've always wondered (Well, not always, but from the time I saw the "Save the whales" star trek movie...)
What makes something transparent?
Take carbon for example. As a lump of coal, it is opaque. As a crystal (diamond) it is transparent. Same chemical, different arrangement of atoms.
Is it theoretically possible to create a transparent aluminum, or steel?
I suppose the Church felt the same way when the light bulb was invented. Also when they discovered electricity and when they figured out that the earth was not flat. "you can't go beyond the ocean. You will fall into the abyss". I reccomend some restrainment first of all. First and foremost if the scientists felt they would wipe out the whole planet they would not go ahead with something like this. After all they ARE humans too with families and friends and everything that goes with being human. Secondly unless you TRY and discover you WILL NOT discover. Thirdly if you read some theory on black holes ( i reccomend stephen hawkins works) you will find out that a black hole with mass 1g is just THAT. A black hole with 1g. DISPITE popular beliefe black holes do NOT suck matter in them and grow larger. In fact if the SUN turned into a black hole tomorrow the earth would still be where it is today. It would not get "sucked in".
Related subject: Jacobson and Volovik have done some work on making superfluid black hole analogues instead of the optical ones being discussed here.
The actual speed of the photons is not reduced going through a medium. (this is the part of relativity) What is reduced is the apparent speed to an opserver (an important distinction). This is due to collisions with particles and fields that misdirect the photon along a much longer path through the object. (I know this is a very elementry explaination, but I fear going deeper)
What this vortex will do is make that path of misdirect infinitly long (ie a cirle like). Therefor the photon will never make it back out.
This is 'simular' to the idea of refraction in optical cable, the material is such that the light is always refracted back within itself (if it enters at a certain angle). what the vortex does is make a circular optical cable with prefect refraction trapping all light within itself. (I know this is an over simplification)
Gork the Enchanter
I still only have 5Gigs of storage. Shared over 3OS's on 2 computers.
1.4Gigs of its MP3s too.
-Yarn - Rio Karma: Excellent
And copper acts as a waveguide for EM waves. Thats why he said 'light' as it doesnt necessarily mean visable light.
-Yarn - Rio Karma: Excellent
If only :)
I expect you could make a 'sonic black hole' using the same idea as this one, but the trouble is that this method doesnt seem to SUCK the light in like a gravitational black hole does. It has to hit part of the vortex to be captured.
-Yarn - Rio Karma: Excellent
"You wont"
"doh!"
-Yarn - Rio Karma: Excellent
Someones been watching too much TV
Gotta be:
"A tornado, for example, attracts with ease substantial ``test particles'' such as cars"
:-)
dylan_-
--
Igor Presnyakov stole my hat
Physics is...not my strong suit. I don't claim it to be so, I'm not an expert in this field, I'm an outside observer that just has a few questions...
For one, exactly how do they propose to keep the water in liquid form?
Water remains liquid only at certain temperature/pressure ratios. Creating a vortex rather quickly creates large pressure differentials(almost by definition), and dumping light into something that isn't going to be able to spit it back out is going to increase temperature. How is the entire mass going to be kept in that one relatively small range that keeps the material liquid? Granted, an excessively smooth container might allow superheating of the fluid(water cannot boil unless there are microscopic ledges upon which bubbles may form, apparently), but having this fluid in contact with *any* other substance is going to create seriously ugly amounts of heat by way of friction.
Even supposing one could accelerate such a material to near-luminal speeds, at minimum a Zero-G environment and a vacuum would be required.
But that's one heck of a supposition! Assuming a massive objects could be spun at such extreme rates is...generous. Am I wrong, here?
I must also ask where the concept of absorption has gone. For a while there, I was imagining they were describing a merger between fiber optic cable and a roach motel--light got in, then was forced to spin round and round the vortex forever. But who said that the water would become instantly clear? As it spun around, wouldn't more and more of it be converted to heat until there was no light left? I'm not slowing down light if I move it through a fiber optic cable that's a kilometer long but on a spool only a foot thick. The light still moved a kilometer, even if (from my "perspective") it only moved a foot. But fiber optic cable is very transparent; water isn't nearly as such--particularly water that bubbles and is highly agitated.
And how would light enter the system if the outside walls of the vortex were so particularly
chaotic? This part, I'm really missing.
Something just seems...wrong here. Someone care to clue me in?
Yours Truly,
Dan Kaminsky
DoxPara Research
http://www.doxpara.com
the speed of light in vacumn is always constant. As light is just a traveling electromagnetic wave it can be retarded by a material it is travelling in
Marriage is the "pseudo-ethics" that cloaks the messy truth of sexuality in the raiment of propriety -- it's "Don't Ask,
Its not a black hole. It is an optical black hole which just means that light gets stuck in this vortex. It will no more emit hawking radiation than a mirrored room (which hence traps light). This vortex is not gravitational does NOT slow time or any such thing.
Marriage is the "pseudo-ethics" that cloaks the messy truth of sexuality in the raiment of propriety -- it's "Don't Ask,
.... When can I Order my own TARDIS???
;)
Your Working Boy,
It seems to me that there are some tricky special relativity thingies that these guys are forgetting.
Roger.
It will be interesting to see whether they can actually create an "optical black hole", or just asymptotically approach one. Assuming that Hawking is correct, and that black holes emit a quantum radiation which reduces their mass as one-half of a particle/antiparticle pair escape, evaporating in a finite time, and considering the time dilation which requires an infinite time for a particle to actually cross the event horizon, then black holes only exist asymptotically. That is, trapped particles move inward as the event horizon shrinks, and cross it only as it evaporates.
Peace and love, y'all
--
Lord, can somebody teach those physicists the concept of the paragraph????
--
" It's a ligne Maginot-in-the-sky "
So if you swirl the stuff at the speed of C in the substance, it should glow nice and blue due to Cherekenov (spelling probably out) radiation, which happens when you accelerate matter through a medium faster than C in that medium. It just dumps the energy as photons.
C = speed of light.
"Because we are not employing at entry level, offshoring will kill our industry stone dead."
Certifiable bullshit. But who cares. It is still very interesting bullshit...
<^>_<(ô ô)>_<^>
I wonder if it is a mistake or volontary ?
No, it's not. The 'light'speed in copper for example is about 200.000 KM/s. Which is darn slow when you're trying to maximise cable length on a 100 Mbps network...
This is your sig. There are thousands more, but this one is yours.
Conservation may or may not work inside a sigularity or it may be transmitted to another point in this usniverse or another one. Since (luckily) we don't have any close singularities we haven't been able to study what happens inside them. It's very possible these photons are slowed down to an almost absolute stand-still (like in a Bose-Einstein condensate) and are actually accepted into the singularity as more mass. The energy of the photon increasing the energy of the singularity but the increased mass of the singularity counterbalances the energy inserted into the singularity. That would make it theoretically possible for conservation to work within a singularity. Singularities don't suck in light like a vacuum, they warp space-time and bend the path of the light into infinite vortexes. Light whose path isn't bent 100% would be sent off in on a tangent of the event horizon if it didn't smack through the matter swirling in the event horizon.
I'm a loner Dottie, a Rebel.
A black hole (in the sense of a gravitational black hole) actually destroys the photons etc.
No, that is not possible; conservation of energy expressly forbids such a thing from happening. In this case, as in all others, the energy is simply converted to some other form.
As for a brick being the same thing, that is also incorrect. The difference is that even the brick reflects light, otherwise you would be unable to see it. A black hole, however, not only does not reflect any light at all, it actually "sucks in" light that strays too close. In the case of the "fluidic black hole", presumably any light that strays too close to the vortex will similarly be sucked in.
Cheers,
Tim
It's official. Most of you are morons.
I think it's more along the lines of this...
;)
Light is *not* a constant speed, it is only a constant for a given energy density of space.
When light travels through air, or water, it slows down (albeit not by much).
I Think the theory goes that if you make it pass through a gas with a very high density.. it slows down even more.. and a BEC (Bose-Einstein Condensate) I believe can be used to create a gas or other transparent material with a very high energy density (BEC, if I recall, is basically a whole bunch of atomic nuclei stuck together acting like one large atom.. something like that).
If this density is high enough, and the material is trasparent, in theory the speed of light throug the material could be slowed extremely.
You are right, though.. they will make a whirlpool spinning at near light speed because they have slowed the speed of light
This could lead to effective miniblinds?
take a stick and put one of those black holes at one end and a handle with laser emitters all around at the other end. Set the laser freq. at the proper freq. of the black hole and point them at the singularity...
Tah dah!!! you made yourself a nice lightsabre!!!
it's hilarious and informative.
Coming soon - pyrogyra
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--- Hot Shot City is particularly good.
Bricks do not produce Hawking Radiation. It's that quantum effect that makes this experiment exciting and unusual.
Hawking radiation originates in the background of virtual particles in the universe -- particles that appear spontaneously from nothing along with their antiparticles, then collide and exterminate themselves. This background energy is a vital part of our models of the universe.
Stephen Hawking theorized that near a black hole some these virtual particles would be sucked into the black hole while their antiparticles would remain free. Thus, some virtual particles become permanent and real particles, and the black hole effectively radiates them into space. Conservation of mass states that the black hole must then be shrinking slowly in size...but that's not important here, with the laboratory optical black hole.
The optical black hole will have the same effect as a real one; virtual particles will be trapped within it, and their antiparticles will fly free. (Note that the trapped particles may be either matter or antimatter -- the radiated particles will be the opposite of the ones trapped.) Scientists will then be able to measure this Hawking Radiation and test some very central theories of cosmology and quantum physics.
Theoretically (and there's a point at which the theory is so remote, it's only fantasy...but here goes), an optical black hole *might* be configured to collect the radiated antiparticles as a bose condensate themselves. Then the optical black hole serves a purpose -- it's an antimatter generator. But that's really, really far beyond what they're trying to do now.
...
Remus Shepherd
Yes, I am a physicist. Yes, I do play one on Usenet.
Genocide Man -- Life is funny. Death is funnier. Mass murder can be hilarious.
This is not quite correct. The speed of light in a dielectric depends on the index of refraction, n, of the medium; n is in turn a function of the magnetic permeability, mu, and dielectric constant, epsilon of the material. At the root of it all mu and epsilon are functions of the molecular and electronic structure of the medium, as well as the frequency of the light itself. Thus, two materials with similar densities but very different dielectric constants will have very different indices of refraction, and hence light will propogate within them at different speeds. What's more, even for a single material, n (and hence the speed of light) will in general vary with wavelength. This is called "dispersion", and it is responsible for such diverse phenomena as rainbows, prisms, and smearing of pulses from pulsars.
The important thing to remember is that only the speed of light in vacuo functions as an absolute "speed limit". Particles can and do exceed the speeds of light in dielectric media, causing them to emit Cerenkov radiation in the process.
-r
-r
What's more, from the standpoint of General Relativity these constructs don't look anything like a black hole. The stress-energy tensor (the relativistic analog of mass density) is virtually unchanged by the modest rotational flows light traps made from Bose-Einstein condensate would require, meaning that these constructs should have exactly the gravitational properties you would expect of a static body of liquid in the laboratory (i.e. none to speak of). That means no space-time curvature, no ergosphere or frame dragging, no gravitational redshift, and no time dilation. For example, if they directed a stream of muons through these things they should find the muons' decay lifetime basically unchanged from what it would be if they sent the muons through the same liquid while it wasn't rotating.
I believe the authors make an important mistake when they say "... a moving dielectric medium acts on light as an effective gravitational field." That is clearly not true because this putative "gravitational field" does not obey the equivalence principle; viz. it accelerates light but not matter. The mistake is comparable to saying, "A charged pith ball in an accelerating train car will experience an `effective electric field' which will tend to accelerate it." and proceeding to compute the electromagnetic properties of this moving field. The analogy falls flat because the acceleration is not caused by an electric field, and so it can't be expected to act like one when you study its influence on anything else in the train car. Similarly, although you can compute a gravitational field that would trap light in the same way as these constructs, that doesn't mean that there is actually a gravitational field present, nor does it mean that other effects that would be present for the gravitational field you calculated will actually show up in your apparatus.
None of that means that this isn't interesting research, of course, but as far as I can tell the connection to black holes and astrophysics is nonexistent.
-r
Thing is, a 1g black hole will be *very* small indeed, probably (and I haven't done the math) smaller than elementary particles, which means even if it were stable (no hawking radiation), it would be unlikely to actually intersect any matter. So, if you dropped it through your table, you could probably wait for it to come back to you, as it will enter a free orbit at this point, and won't mysteriously stop at the center of the Earth. A larger black hole (large enough to actually absorb something), might be slowed by passing through the Earth (but, thinking about this, it might actually speed up until it left the atmosphere. Friction doesn't apply to event horizons, y'see, so the only force that could slow it down would be gravity. Now, you have two orbitting masses, one of which is gaining mass from the other, and the fact they intersect is irrelevant...)
You wouldn't be worrying about this anyway, because a 1g black hole would rapidly release rather a lot of energy as it evaporates (E=mc^2...), so you'd probably have some rather more exciting problems to work on... (Like how to reattach severed limbs)
Andrwe.
"about 200.000 KM/s"
uhm, ok, let us review significant figures. You just quoted a number to six decimal places, or one part in 400,000, but prefixed it with the word "about."
It occurs to me that you could be using "." to mean "," but if you want me to accept that, you had better use the correct abbrviation for kilometer, which is km, not KM (Kelvin Mega?).
As others have said, you also oughta be more precise when you talk about light speed in an opaque medium.
Oh come on "-1, troll," it is so obviouly a joke.
Any culture that cannot laugh at itself does not deserve to exist.
People with high karma get automatic +1's to any comment they do not specifically designate "No Score +1 Bonus." That's why there is no reason specified for his score.
My guess is that if the black hole you dropped into the earth were big enough to have a net gain in mass as time progressed (ie it is not evaporating faster than it eats), then you would not get "a century or so." Since the growth of the hole would most likely be fit by y=x^x or some other god-awful function, we'd either be completely safe, or quickly dead.
On the other hand, I am basing this on almost no information. Can anyone point us to a well thought out mathematical model of this?
You are right, if the sun turned into a black hole, Earth would go on happily orbiting because the gravitational effects out here would not change. [Perhaps the added spin of the sun would make a bit of a difference, but I don't know what is conserved in this case]
However, there is a large difference between a 1g block of steel and a 1g black hole if you are trying to keep it sitting on a table [or in any other non-vacuum]. The steel and the hole will have the same gravitational effect if you are 2cm away from the center of each, but anything very close to the hole WILL get sucked in, because the gravity DOES make the escape velocity rise to above the speed of light as you move towards it. If you "set" your 1g black hole down on the table, it would not and could not be supported and would fall straight thru any matter in its way until it got to the center of the earth. As it went and once it was there, it most definitly continue to suck matter in. Perhaps the rate of suck would be very small at first, since particles have to get real close in order to be trapped, but the more that it eats, the more it sucks.
On the other hand: A 1g black hole would evaporate (read: explode) very quickly due to hawking radiation.
And: They are not making black holes anyway, that is just an analogy, RTFArticle.
Good point about it not stopping at the center. I never thought of that, and I think a whole lot of science fiction writers miss it as well.
At some point I will do the math for [1g black hole versus density of particles it will encounter] and [time it takes to explode due to hawking radiation], but right now I am too overworked already.
> No,but seriously, even if you could create a > conductive core which could touch a black hole > (precisely on the event horizon) any electricity
> would instanty be consumed by the hole itself; > or rather the matter entering the hole > (electrons being a component of matter but
> inexistent without it)
But that's exactly the point... electric charge is always conserved. If electrically charged matter enters a black hole, the black hole must now have electric charge.
An even better way to charge a black hole would be simply to set up a bunch of electron guns, and shoot at the hole for a while. Eventually it'll get a charge, at which point some magnets would be just fine in moving it. True, it'd have a huge inertia, but it'd move.
In general, true black holes (not these optical ones) have 3 properties:
1) Mass
2) Charge
3) Angular momentum. (i.e. spin)
All other information disappears.
Thus the saying, "black holes have no hair"
Well, it seens it is always the samething.
Today, they build the dam thing in a Lab. Next week, you will be able to buy one of them for a couple thousand bucks at ebay. Them they hit the shelves at Amazon and other places...
In a year or so they will be comming free with your favorite breakfast cereal...
Hmmm...I think that not even Galactus would have dreant of that. Should make a nice sauce to go with planets.
Of course they had already had the technology to do this on the past, but it seens they had improved something on security since.
-><- no
I think that you are trying to be funny, but just in case its not that (or for clueless moderators): The speed of light in a given medium is constant. When light will switch over from one medium too another, it will merely refract. So no BSOD, because the light will be swapping media, and refracting to account for the swap.
I can throw myself at the ground, and miss.
--
The shareholder is always right.
What happens when you turn it off? Does all the light that was trapped come back out and burn everything around it? Sounds nasty to me.
Where is my mind?
Check out Project Upper/Mute, an all-around awesome compiler fra
Read the article! They're NOT making a black hole, it's just an optics experiment. They want to study the effect of light in a moving medium, where the speed of light in that medium is very slow. They won't even have to "stir" it that fast. The worst that could happen is that, as more photons pile up at the "event horizon", where they will eventually just be absorbed by the medium and converted to heat, it will raise the temperature of the bose-einstein condensate enough to undergo a phase change (back to regular old cold rubidium atoms, I suppose). There may be a dim flash of light during the phase change... just a guess.
The whole experiment is about as dangerous as playing with a laser pointer.
-CausticPuppy "Of all the people I know, you're certainly one of them." -Somebody I don't know
The flash......
...who exactly is going to stir this liquid at the speed of light?
stty erase ^H
Through a mirale of modern science we have found what to do with all those AOL disks
Unfortunatly this opinion is backed up by other sources: Bad Coriolis
And for the Simpsons fans out there...[2F13] Bart vs. Australia
There are other sources - check Google. Of course there are probably sites out there that encourage the myth, but that's the nature of myths.
http://harridanic.com
From the 2nd link, it refers to the sci.physics FAQ - which I hope would be a reputable source of information: Which Way Will my Bathtub Drain?
wrt your comment on the author of the first site, I'm inclined to agree.
http://harridanic.com
RECIPE FOR MENTAL BLACK HOLE:
<---[singularity sig]
There is actually:
Black holes can be electrically charged, and can therefore be moved using magnetic fields.
It would be rather amusing if they managed to create one and it started sucking down everything we know. That would rock.
Optical Black Holes reference:
U. Leonhard and P. Piwnicki, Physical Review Letters, 84, 822-825(2000).
This is the actual reference to the paper proposing optical black holes. It has been published in what is arguably the most respected physics journal(not some speculative rag). Many of you are asking about a material in which the speed of light is very slow. Such a material was demonstrated last year:
L. V. Hau, S. E. Harris, Z. Dutton, and C. H. Behroozi, Nature(London) 397, 594(1999).
In this paper Hau et. al. demonstrated that light traveling through a Bose Einstein Condensate is slowed to a mere 17 m/s. This is slower than most bicycles ride(as illustrated by the cover of that weeks nature). To find out what Bose Einstein Condensate is you can refer to:
Anderson, M. H., Ensher, J. R., Matthews, M. R., Wieman, C. E. & Cornell, E. A. Observation of Bose-Einstein condensation in a dilute atomic vapor. Science 269, 198-201 (1995).
Now go to your local University Physics Library and look a few of these things up before advertising your ignorance and pronouncing that this is bullshit just cause you read some bullshit article on real science
... if you would you would understand, that it's not a real black that will be created but something that will have similar behaviour... Jeez,... its those scientist you seem to distrust so much that've told you all they suppose about black holes. They're the ones who make back of the envelope estimates. Yet you think you (clearly someone who gets all his knowledge from SF-comic books or movies) understand the dangers better than they do,... oh puh-lease, If you know nothing, understand nothing and have no clue whatsoever what you are talking about just shut up will you... (Oh yeah, real (wo)men post their name) J.
... if you would you would understand,
that it's not a real black that will be
created but something that will have
similar behaviour...
Jeez,...
its those scientist you seem to distrust
so much that've told you all they suppose
about black holes. They're the ones who
make back of the envelope estimates. Yet
you think you (clearly someone who gets all
his knowledge from SF-comic books or movies)
understand the dangers better than they do,...
oh puh-lease,
If you know nothing, understand nothing
and have no clue whatsoever what you are
talking about just shut up will you...
(Oh yeah, real (wo)men post their name)
J.
P.S. sorry messed up lay-out last time
"We are very exited by this" says a spokesman for the Unmoving Picture Association "Maybe it is possible to create a device so that information cannot escape its proximities, or at least bend over"
All opinions are my own - until criticized
If an optical black hole can be created by passing light through a medium that causes the light to slow down relative to the speed of the vortex, does this mean that the observed effect (specific-frequency light can't escape) is caused completely by the vortex? This could lead me to believe that a REAL black hole only creates a gravity well because it creates such a strong vortex in the medium of spacetime. This may already be the common belief of black holes, but I always thought that a black hole was just a massive point in space that sucked stuff straight into it and matter falling into it followed the path of a vortex. Could it be that the gravity well surrounding a singularity is CAUSED by the vortex action around it?
Making black holes scares the hell out of me anyways, so I don't think it's interesting at all.
Bizar technology?
Of course, users of modern universes will gleefully point out that, in theirs, light rarely actually swaps -- it pages using an LRU algorithm.
Just through enough storage at it, and it won't ever swap. 640 kilophotons should be enough for anyone.
Of course, users of modern universes will gleefully point out that, in theirs, light rarely actually swaps -- it pages using an LRU algorithm.
Practice random senselessness and act kind of beautiful.
Then it sounds like this experiment, modified, could result in the instantaneous destruction of the universe:
First, get the light within the artificial vortex to slow down.
Then, place the device containing the experiment within a good-quality vaccuum, like an Electrolux (or an old VAX).
At that point, the light within the experimental device has a problem -- it's supposed to go the speed of light 'cause it's in a vaccuum, but it's supposed to go slower because it's going through some other materials.
The result of this contradiction might be the immediate destruction of the entire universe, followed by some quick behind-the-scenes fixing of microcode bugs and a reboot. (This sort of crash is known by the heavenly hackers as a "BSOD", or "Black Suck of Death".)
(Or, we might just learn which if these "laws" is wrong!)
Practice random senselessness and act kind of beautiful.
Why don't they work on something that will suck up all the silly comments on /. so then noone has to worry about Moderation and Meta Moderation and all that.
How do we do this?
You seem to be confused. Yes, both say a sealed box and an optical "black hole" stop you seing light in a basic sense, there are large diferences that you seemed to have missed.
A black hole (in the sense of a gravitational black hole) actually destroys the photons etc. as they enter it. A box simple stops the light getting to your eyes. The light is still in that box, and it would eventually be converted into other energy forms (I.E heat).
Syllable : It's an Operating System
Well, i suppose i was close. Must remember to get hold of a copy of Dr Hawkings book. :)
Syllable : It's an Operating System
''If a sufficiently fast-spinning vortex of these or similar materials could be created, light inside the fluid could lose maneuverability and become trapped in the vortex'' Hmmm sounds like a different approach of making light emitting fluids like the jellyfish dna-method. :)
Regards,
It is theoretically possible to create a black hole in one's own basement/backyard. Many of you may be familiar with digital sampling. One of the main priciples behind digital sampling is that in order to get a decent digital copy of an analog sound is to ensure that your sampling frequency is at least twice your highest analog signal frequency. To ensure with out a doubt that you have a quality digital sample we simply need to drive the sampling frequency toward infinity. The amount of energy required to make an infinitely small time slice will theoretically create a small black hole. Of course, as it sucks things in, it will grow in size.
The text shows that these only trap light by chemical means in order to simulate a black hole, there is no actual gravity well produced :)
Ripping an new rectum in the fabric of spacetime.
BTW there is no theoretical or practical means of containing a gravity well black hole
:)
A black hole will contain you before you can contain it
Ripping an new rectum in the fabric of spacetime.
Ive tried electrical fields before, but the grass was imperfect :)
:)
No,but seriously, even if you could create a conductive core which could touch a black hole (precisely on the event horizon) any electricity would instanty be consumed by the hole itself; or rather the matter entering the hole (electrons being a component of matter but inexistent without it)
I however do know of one plausible way of moving (not containing) a very small black hole: you can 'tow' an object of simmilar mass infront of you black hole and the black hole will be constantly attracted to your object, and so long as your object doesn't approach the event horizon you are safe - quite how you re orient yourself to stop your 'hole' is another matter
The major problem with moving a hole this way is a - there is no scientific proof or disproof that an 'event' can exist in any other place other than where it begins.
b - the energy needed to pull your 'equally massive object' would somewhere in the order of 10_-100,000,000,000Nm
As for how much matter you would need to create a charge high enough to charge the event horizon; every particle in the universe might be a good start.
And if you could use an electronic field to attract a hole, your still left with the same problem of how to generate enough energy to move your cosmic 'tow' vehicle.
The bottom line is that a gravity well at critical mass (a black hole) the size of a teacup would have roughly equal mass to 1 sun: if it oversteps critical mass, you haven't got enough fingers & toes to count the relative mass....
Ripping an new rectum in the fabric of spacetime.
Yes but the inertia of even the smallest black hole (smallest critical mass to cause an event) is so incomprehesibly massive (literally) that if you got you magnets to 'attract the hole', the magnets + whatever they were attached to would rather go to the hole than the hole come to you...... not: I cant remember what the smallest possible critical mass of on 'hole is but I saw the figure and remeber being blow away by it! My brain hurts: lets go talk about OSS now (another blackhole some would say) :)
Ripping an new rectum in the fabric of spacetime.
Thats more or less what I said :)
Ripping an new rectum in the fabric of spacetime.
It seems that everything you talk about relating to black holes is a paradox, it tookme a few seconds to work this out (because they expect you to know what *they* are talking about):
:)
;)
Here goes: They use the word 'comparable' when it may have been better to use 'relative'.
The gist of it is you can't accelerate matter up to the speed of light; therefore you slow the light down instead. So you don't need a whirlpool which spins at hundreds of thousands of miles
per hour
It would be interesting to see if some of Steven Hawkings theory is correct, and if you haven't read the 'brief history of time' go out and buy now! (but not from amazon.com) its worth it just to have on the coffee table when friends are round
(friend:"ooh, whats that book about" you:"well....")
Maybe you all understood better than I, just thought I would post this incase anyone was left scratching their head.....
Ripping an new rectum in the fabric of spacetime.
Actually, no we aren't. Not in the important sense of a gravitational singularity. This is merely something that simulates some aspects of a black hole, namely that light goes in and doesn't come out. Theory suggests that this violates preservation of information, meaning that there must be some other force at work countering it. That's the radiation part. To examine this would be an interesting insight into a realm we don't know much about.
But this is not a dangerous experiment in any way. Your armageddon scenario fails because there isn't any actual singularity in the picture.
-- Eythain
PS Besides, the 30 minutes calculation for a real balck hole is way off, or rather, that would depend entirely on the mass of the black hole in question. A natural black hole from a collapsed neutron star would squish us before we even got close, whereas a quantum black hole we could concievably make would probably be so small it would evaporate, or even if it wasn't, it would not significantly affect the Earth (I mean, it's not likely we can make a black hole a significant fraction the mass of Earth, where would that mass come from?) while growing. Since a singularity this small is basically point sized (even the event horizon), it would be severely limited in how quickly it could swallow matter. So relax, we'd certainly have a century or so to evacuate, even in the worst case scenario.
A good book on that horror scenario would be Earth, by David Brin.
Even if we were talking about a gravitational black hole, it would not be particularly dangerous at the sizes we're talking about. What makes a black hole a black hole is not its mass, but its density. Theoretically, if you replaced our sun with a black hole of the same mass, Earth's orbit would remain unchanged, because the gravitational force is still given by Newton's equation F=(G(Msun*Mearth))/a^2 (G is the universal constant of gravitation, a is the semimajor axis of earth's orbit). If we took a bucket of water and compressed it into its Schwarzchild radius (that's how you make a black hole, by the way), which would be a couple millionths of a meter (I don't have time to calculate the actual radius now), at normal distances the gravitational effects of this black hole would be the same as for an ordinary bucket of water. It's only when you get near the event horizon (which is the same as the Schwarzchild radius, btw) that you get those wonky relativistic effects.
Seems some of us are forgetting our high school physics.
--Kevryn
After all, who wants to see that water anyway? ;)
Tepp
In the meantime, physicists are also pursuing the idea of creating "acoustical black holes" (dumb holes),
It's already been done: Courtney Love and her band.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
I've seen something similar done with a Biro and a pint of Guinness. Once you stir the Guinness quick enough, a vortex is created which sucks the ink out of the Biro.
Stephen Hawking has written another book. It's about time as well.
This has the possiblity of becoming a large scientific field, as studying a real black hole would be rather difficult (only possible assuming we ever figure out intersteller travel anyway) this could provide a lot of insight on the mechanics of the universe, with the added bonus of not having to leave our own back yards, so to speak :)
Umm...did you read the article? these are optical black holes, they only affect light, and these "holes" would be a parellel to what happens to mass in a real black hole. So unless you are composed entirely of photons, I don't think you have too much to worry about.
"The idea is to use a medium where light is only going something like a few meters per second..."
A medium? That sounds more like sorcery than science. Is it done with crystals?
I think that if science can invent air brakes (presumably to help us brake wind), then why not invent light brakes to slow their light down? This is different than brake lights which are just an indicator (usually of the speed of traffic, not light).
Also, if they slow the light down, wouldn't it only be an optical brown hole? And since it's not a real black hole (or brown), but only an optical one, what's to prevent people from checking it out and saying, "I just don't see it"?
--
As a matter of fact, I am a lawyer. But I play an actor on TV.
How can an accelerator worry about anything?
Didn't we talk about OPTICAL BLACK HOLES. RTAF - read the announcement first! I think a bucket would do for containment.
You missed my point. I was exactly saying that a gravitational black hole and an optical black hole are *not* the same.
I think you missed the 'Else' in parsing the second para of my post.
A lot of people optimize the "read.. think.. reply" algorithm down to two steps, but lets not shorten it down to *one* !
What a load of bunkum. There's a world of difference (yuk yuk yuk) between an optically inescapable region and a gravitationally inescapable one.
Else I just made a black hole by lighting a cylume stick inside a brick, or putting a flashlight in a draw an closing it. Or drawing the blinds.
Rotating fluid faster than the speed of light within it is like putting a brick on the table and saying that it's going faster than the speed of light within it. Or sitting stock still in a vacuum and saying you're going faster than the speed of sound.