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Hawking Radiation Claimed Created In a Lab
eldavojohn writes "In 1974, a young newcomer to the Royal Society named Stephen Hawking predicted that black holes emit Hawking Radiation. Researchers have been looking for it in space ever since. A new paper up for publication claims to have beaten searchers by observing it in a lab. Doing it wasn't easy. They say they brought light to a standstill by drastically increasing the refractive index of the material it was being fired at, creating a 'white hole.' This horizon, beyond which light cannot penetrate (event horizon), is the same between white and black holes, which caused the team to suspect they observed Hawking Radiation when light of a different uniform wavelength than the input laser was emitted. But, before you rejoice, the Tech Review article notes, 'Of course, the big question is whether the emitted light is generated by some other mechanism such as Cerenkov radiation, scattering or, in particular, fluorescence which is the hardest to rule out.'"
Yay, the LHC will not kill us all!
What I want to know is if this could be used to create a cool sort of battery or capacitor. I'm imagining layers of metamaterials to store the photons with only a certain amount of predictable Hawking radiation emitted. I doubt if it'd be better than chemical batteries but the geek cred would be way up there.
-l
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pics or it didn't happen
I read TFA and all I got was this lousy cookie
OK, either you're a troll and I'm wasting my time (most likely) or you're misunderstanding something. What Hawking admitted wasn't that the radiation didnt' exist but that the radiation did not in fact violate the principle of conservation of information. Previously Hawking had believed that it must violate said principle because there was no understood way for there to be a connection between the information about the matter that had fallen in and gone past the event horizon and the radiation that would be emitted. This was challenged by another physicist, whose name escapes me since I can't look it up at the moment, who reasoned (along with a more definite proof of course) that the information gets left at the event horizon also. This is because of the fact that from the perspective of anyone outside the event horizon any matter or energy falling in will never actually reach the event horizon it'll just appear to be slowing down further and further until it for all intents and purposes stops. This allows the virtual particles making up hawking radiation to be influenced by the information left at the event horizon without there being a need to have communication between the singularity at the center and the event horizon.
BH evporation is explained on wikipedia with a lot of complicated looking mathimatical forumals, so it must exist. becuase the theory of BH evaproation is to prove itself.
However the proof of the researchers is that they did not find an other source for the ration at 1050 nm, so it must be hawking radiation.
powerful lasers are so cool!!! (or hot.. since they use IR lasers )..
[citation needed]
As far as I know Hawking Radiation and black hole evaporation have not been ruled out. The effect is just so small that there is no experimental evidence of it.
Actually, you'd better hope black holes evaporate or the black holes the LHC might create may destroy the earth! I for one use a tin foil hat just to be safe.
So when the virtual particle pair is created at the event horizon, one is trapped stationary beyond the horizon, and the other escapes (becoming real).
In this experiment obviously the event horizon doesn't persist indefinitely, so when the horizon collapses, do the 'trapped' photons escape? and hence is there a time delayed double emission of the hawking radiation? Would this provide a testable signature?
Any physicists know?
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BTW, on a more serious note: a quick google search of "hawking radiation disproved" doesn't seem to come up with much serious material.
I read TFA and all I got was this lousy cookie
Urgh, I was confident that black holes would evaporate due to Hawking Radiation, that's why I didn't get myself a tinfoil hat when the whole LHC controversy came up. So they are actually going to make black holes at LHC without even knowing if it will evaporate? Or is there another mechanism that will make the black hole diminish that are 10000% confirmed ? Otherwise I can't believe that they are actually going to do that?! Halp? Please?
Can I light a sig ?
IANAP, but if I remember correctly, Hawking first asserted that information was lost via Hawking Radiation but then retracted. I would be curious to see if radiation somehow gave information about the incoming light.
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For those who did not RTFA or article comments, more interesting fiber optic black holes (and pictures!) : http://www.st-andrews.ac.uk/~ulf/fibre.html
I wish I had mod points. That was a concise and useful answer.
By the way, even if this experiment and their conclusions hold water, it is not a proof of black hole evaporation or Hawking radiation. It would be more like a proof of concept.
In the experiment, they've created a pseudo-event-horizon from which light can't escape. It's only a light event horizon though. Shoot a bullet through their material and you will definately see it go through the event horizon without any problems.
The similarities to a real black hole is that photon pairs created on the pseudo-event-horizon should create radiation if Hawkings reasoning about real black holes is correct. So, it would show that Hawkings thought experiment had some merit but not that black holes necessarily radiate.
So, with the advent of this new 'white hole' technology, we're really just a few short years from sucking matter through them to create our own custom luxury planets. I really want one of those rubber planets with lots of earthquakes.
This one's tricky. You have to use imaginary numbers, like eleventeen... --Hobbes
I don't understand how Hawking radiation causes a black hole to evaporate. Okay, a particle/anti-particle pair gets created from the ambient energy near the event horizon. Okay, one of the particles falls in and the other escapes. With you so far. Now, either way, the black hole gains the mass of that one particle that fell in, thus it gets heavier. Even if the physics inside the black hole allowed the trapped particle to meet an anti-particle and get annihilated, that energy (and thus the mass) would still remain inside the black hole.
Granted, the escaping particle is carrying away energy (and thus mass), but that energy must have come from outside the event horizon, not inside. The outside universe got lighter, not the black hole.
What am I missing?
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"I call it a Hawking Hole."
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Don't you mean Fry-radiation?
umm, is this what you're talking about?
weinersmith
Even if the black holes the LHC might create don't evaporate, they'd be rather harmless.
Why? Well their radius is terribly small so the chances of collisions with anything else are pretty small. Furthermore, their mass is extremely small as well and gravity is the weakest of the forces. They would have a extremely difficult time ever gaining more mass.
Not to mention, if they don't evaporate then there is a fair chance they are all over the place already, thanks to cosmic ray strikes.
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So they are actually going to make black holes at LHC without even knowing if it will evaporate?
For the LHC to create black holes at all would require a whole bunch of very speculative physics to be true, and a whole bunch of very well-established physics to be false.
In particular, if the LHC can create black holes then millions of black holes are being created every day by cosmic rays, which can have twenty orders of magnitude more energy than the LHC. No evidence of those black holes is seen anywhere, not in geochemical track analysis, not in the radiation signature of cosmic ray showers, no where. Ergo, either such black holes are not being created, or they are being destroyed with incredible rapidity.
For the beam dump of the LHC to behave any differently would require physics so arcane as to be basically magic, and anyone who is worried about it should also be terrified that a herd of flying elephants will trample them to death, because that's a far more probable event.
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If light cannot penetrate a field, does that mean that what is inside the field cannot be seen?
You'd not be able to see the other side of it, so it won't be invisible.I'm not too sure what you'd see - My mind hurts - not much pain - but enuff(sic).
We also now create black holes in labs. Could we create pairs of white holes and black holes together in a lab, and study the gradient between them for gravitons? Would we be able to pair them into gravity diodes? If so, could a gravity laser be made from them?
Could we use a gravity laser to focus Hawking radiation onto "blank" quanta to reconstitute the entropic hologram of the complex structure that a black hole reduces to those "blank" quanta when it emits the Hawking radiation?
If so, could we entangle pairs photons, send each member of each pair across space in opposite directions, then work one of the pair against the Hawking radiation to encode it across to the other of the photon pair, which in turn modulates "blank" Hawking radiation at the far end through a gravity laser, reconstituting the quantum entropic state of remote blanks? If so, we'd have teleportation that could run at least double the speed of light on demand (entangled photons rushing at c to opposite points = 2c), and if prepared in advance simply instantaneous teleportation.
Will Hawking finally deserve the "greatest brain of our time" reputation that TV acts like he does?
--
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The model that predicts Hawking radiation is the only model that would let them produce miniature black holes in the first place.
Sing it with me: "you can't have one... without the other!"
Similar energetic collisions happen in the upper atmosphere because of cosmic radiation. That's why you need the tin foil hat! (not tin foil shoes)
http://public.web.cern.ch/public/en/lhc/safety-en.html
I can't fucking stand the racism in scientific research these days. They are ALL holes. Your momma taught you better....
...They say they brought light to a standstill by drastically increasing the refractive index of the material it was being fired at...
They tried to take pics but somehow there wasn't enough light..
what are the practical applications for the real world? How will this help prevent our extinction?
They're using their grammar skills there.
Not quite, i was referring to this. i couldn't look that up earlier because i was on a really bad connection that was dropping packets left right and center.
July 22nd, 2004: ' ' Now Hawking has conceded defeat by saying that information can escape from a black hole and therefore is not lost. "It is great to solve a problem that has been troubling me for 30 years," said Hawking, "even though the answer is less exciting than the alternative I suggested." ' '[http://physicsworld.com/cws/article/news/19926]
If my calculations are correct, then you can just simulate a black hole on paper, write some formula describing information emitting from the black hole, and perform just as much as these people did with their convoluted, inverse-proof, "white hole".
Besides, none of this matters. The entire reason why the sky is so dark and has more light on one side than the other isn't "broken symmetry" and "gravity bends spacetime" and so on, it's that the planet Earth and the visible "universe" are just a small portion of what actually exists except it's been sucked into a black hole that we can't see out of (information). It's disproportionately tilted to one side because it's vortexing into the center where everything gets crushed simultaneously.
"Stratigraphically the origin of agriculture and thermonuclear destruction will appear essentially simultaneous" -- Lee
Whenever I read the term "hawking radiation" I think of the black hole hawking some radiation. Or perhaps radiation emitted in the process of hawking something else. Fortunately this mind glitch does not happen when I read this in the context of the guys name.
Isn't it a bit too coincidental that a guy named Stephen Hawking would discover something called Hawking radiation. I call BS.
'BTW, on a more serious note: a quick google search of "hawking radiation disproved" [google.com] doesn't seem to come up with much serious material.'
Well, you generally shouldn't come up with a lot of material for or against this theory; you need a black hole to really test it.
We all understand what Hawking radiation is, right? Its the run-off of actual particles created when a virtual particle pair "pops" into existence near the event horizon of a black hole; normally the two annihilate each other but in this case one of the two gets sucked into the black hole, the other shoots off into spacetime. This also gives the hole a little negative mass, leading to the other huge implication in this theory; black holes can evaporate.
Python: 'And then suddenly you have a language which says "we're all stuck with whatever the whiniest coder wants".'
Python: 'And then suddenly you have a language which says "we're all stuck with whatever the whiniest coder wants".'
i was on a really bad connection that was dropping packets left right and center.
So, you're saying that your information was falling into a black hole and you couldn't retrieve it from the event horizon???
Yeah I remember now... the story was intriguing and promising at the beginning and then it all went trough hell.
hey say they brought light to a standstill by drastically increasing the refractive index of the material it was being fired at -- creating a 'white hole.'
"I call it a Hawking Hole."
There are some people that if they don't know, you can't tell 'em.
Why would the black hole diminish? Shouldn't the same amount of virtual particles and virtual anti-particles cross the event horizon?
- Raynet --> .
yes, but high energy cosmic particles all have huge momentum with respect to the earth, so no matter what they do, the original particle is either gone or the thing it hit blows through the other side at about the speed of light. But because we smash beams into each other from opposite direction, many black holes (if created) would have near zero net momentum (less than escape velocity). The real evidence is that there exist very dense stars with incredible escape velocities that also get bombarded with these particles, and they don't get turned into black holes very quickly, so, in the worst case, we should be fine for at least a few million or billion years (crosses fingers).
Although, the black holes that can currently evaporate due to this mechanism are (as I understand it) well below stellar mass. The amount of hawking radiation that larger black holes emit is below the amount of energy they receive from the cosmic microwave background, thus they cannot evaporate.
They brought light to a standstill? I'd love to see that.
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The way I remember it is Hawking radiation is when a set of virtual particles get split up, leaving antimatter on the edge of an event horizon. Then that antimatter reacts with matter and gives off all kinds of radiation including light so black holes sort of "glow." So given the estimated energy levels of antimatter and matter reactions, wouldn't one of those antimatter particles contacted some matter and blown them all the hell up?
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Both particles and antiparticles escaping carry positive energy away from the black hole. The consumed virtual particles carry negative energy into the black hole. Therefore the mass decreases.
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It sounds like the light they see is monochromatic. Hawking radiation would be blackbody radiation. Unless they have a reason why this blackbody would only have one mode and an incredibly high effective temperature. I'm guessing that they've found an uninteresting fluorescence feature.
Technology review's arXiv blog is so difficult to get any details out of. It's hard to figure out what these people have done. "frequency of 1055 nm"? I guess I'll have to go to the full article.
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This is what First Contact will be like for us. If we're lucky. Note that I didn't bother to exterminate the critters.
Leonard Susskind was the guy and the problem wasn't originally an "information" problem, but instead an entropy problem. The information questions came in after they sorted out the holographic principals of information representation along the surface area of the event horizon.
Sean M Carroll has a good book about what that means for time if you are interested...
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"which can have twenty orders of magnitude more energy than the LHC"
I'll be dam...... time to go double layer on that tinfoil hat.
Looks interesting, i've added it to my list of too many things to read, i'll get to it eventually i hope.
Particles are points, right? I.e. of zero size, and therefore infinite density. So why doesn't (e.g.) an electron immediately collapse to form a black hole?
I am trolling
This isn't Hawking radiation, it's only an analogue. Now, that's not to say that it isn't an interesting and cool piece of research, but it certainly is not the black body spectrum produced by the evaporation of a black hole. So all they've really seen is that IF a real black hole behaves in the same way as their system, it will emit hawking radiation in the same way.
So, Long story short is I'm not going to get a cool new device that replaces the microwave AND the trash compactor at the same time? I always let these headlines build my hopes for a better future... You'd think I would learn...
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An electron's classical radius isn't zero, but more to the point, you can't use just classical physics at that scale.
Can someone please explain to me why Hawking radiation does not violate the first law of thermodynamics?
As I understand Hawking radiation, two particles emerge from a black hole and circle each other, and eventually get sucked back in disappearing into where they came from. Although sometimes when they are near the event horizon, only one of the particles gets sucked back in, and the other stays behind which is known as hawking radiation.
Is this not the same as energy seemingly being created, just appearing out of nowhere? Or is it mass, and the first law does not apply?
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No, an electron is about 10 ^-22 meters across, or at least as best we can measure something that small.
This is the way I understand it (probably wrong): because of quantum mechanix hocus pocus, any point in space-time does not have zero-energy. Also, that energy state isn't perfectly stable, so occasionally it causes virtual particles to appear. Those particles are complementary matter / anti-matter particles, and under normal conditions, they quickly annihilate each other after their birth. However, very very close the event horizon, some unfortunate particle is sucked it while their siblings have the right velocity and distance away from the black hole that they run away. Remember that there's conservation of energy/mass (mass and energy can convert into each other, but you can't actually destroy or create them). So because of that conservation, and since the black hole is emitting radiation, the black hole is losing mass/energy.
I *guess* (see:not researched) that because space-time really doesn't like very low energy states that it somehow sucks energy from surroundings, ie slowly pumping energy to the event horizon from a little bit inside, and that concentric zone dips in energy and sucks some more from the space inside that, etc until you get to the singularity. But that seems to contradict the whole "point-of-no-return", so I really don't know how it works.
Black holes are fucking weird.
I read TFA and all I got was this lousy cookie
Well, I predict that they emit Anonymous Coward radiation.
Why does the outside world get 'heavier' as the black hole gets 'lighter'?
That certainly makes sense if, in the virtual pair, the particle escapes the event horizon and the anti-particle falls in to the black hole.
But isn't it just as likely the anti-particle escapes and the particle falls in the black hole? Doesn't that mean there is no net energy gained or lost? All the particles and anti-particles escaping cancel each other out.
Now, you could say, when a particle and anti-particle meet, the energy released is equivalent to the energy lost from the black hole. Except these are particles 'born' outside of the black hole to begin with. This is just energy outside of the black hole that has moved from one place/form to another.
Where in this process does the black hole lose energy?
Of course, the entire reasoning is based on wild analogies and guesses. Normal physical laws may well break down at singularities entirely, meaning that normal conservation laws may also break down.
In 1974, a young newcomer to the Royal Society named Stephen Hawking predicted that black holes emit Hawking Radiation.
I'm gonna go out on a limb here and guess that in 1974 a young newcomer named Stephen Hawking predicted that black holes emit a certain kind of radiation, and somebody later named in Hawking Radiation.
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But what about the normal particles falling into the black hole? Why don't the cancel out the antiparticles, on average? (I'm not a physicist, I never understood Hawking radiation)
While I too am not a physicist, my understanding is that, while normal particles are falling into the black hole, it is increasing its mass faster than it is losing it. However, for black holes that do not have an accretion disk or other inflow of matter, Hawking radiation would cause a slow but net decrease in mass of the black hole.
No, this is the upper limit that can be established by the best experiment to date. As far as both theory (String theory notwithstanding) and experiment are concern, electron is a particle with no internal structure.
The only possible interpretation of any research whatever in the 'social sciences' is: some do, some don't
As noted by others, those particles don't have zero radius.
For fun though, you can calculate the radius different masses would have to have to collapse into a singularity.
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I would have posted a reply before simcop2387 did... time dilation is a bitch.
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The charge or any other quantum property of the particle is immaterial, the net gain of energy is negative due to the action of a rather convoluted series of interactions related to black body radiation in a vacuum. If you want to read about it just google "hawking radiation black hole evaporation" but I promise the plainest explanation of it is deeply mathematical. If your not mathematically inclined (like me) you can read it and you might as well be reading Greek.
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...theory.
You keep using that word. I do not think it means what you think it means. More precisely, you're using the wrong definition.
A theory, in science, is a system of explanations to describe the observations. As more observations come along, theories change, filling holes that the old theories couldn't explain. New and completely different systems sometimes can describe different circumstances better, so we get conflicting theories.
An example theory, proposed by a child, is that the sky is blue with clouds because the Earth is inside a blue ball with white spots. After flying in an airplane, the new theory is that the clouds are inside the blue ball as well. The theoretical model is still wrong, but it's more complex than it was before, and a little more accurate.
Theoretical research is still research. Possibly-correct models are laid out, and their effects are calculated, with comparisons to all known previous observations and models. If the model's obviously wrong, it's easily abandoned. If the model matches 99% of previous observations, the disagreements are examined, and new theories fill those holes. Eventually, enough rules are established that every significant detail of an experiment can be accounted for - and that's when the really fun experiments start.
Seriously... We (speaking for the human race in general) have some rough ideas of how matter behaves. If those ideas are correct, then we can predict how black holes should behave. If those predictions are correct, then we can predict how particles near a black hole should behave. If those predictions are correct, then we can predict how the black hole would radiate energy in response. If those predictions are correct, then we can predict the properties of that radiation.
That takes a lot of redundant language to describe the levels of predictions, which scientists should simply expect. If only we could remove some of those words, and trust that the meaning would be clear to the intended audience, saying something like "we can predict the properties of Hawking radiation..."
I digress... By duplicating one of the predicted particle behaviors, the scientists observed radiation. The radiation matches what was expected, and now we have more observations. Time to go double-check all those predictions again! Maybe we can even confirm a model, or better yet, disprove it. After all, that's what we've been doing for the last few hundred years.
Theories change often. Some particularly lucky theories stick around for thousands of years before being shown to be wrong. All of our current theories are actually expected to be wrong, in hopes of finding a unified theory that describes everything. That's the way science works. Science is the pursuit of knowledge. It's not the pursuit of being right.
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No, this is incorrect. All it requires is for one very speculative piece of physics to be true: large extra dimensions.
If the only modification to the standard model is large extra dimensions, then it's just like any other particle physics experiment, where decay rates are closely related to formation rates. The black holes decay essentially instantaneously. That is why theories with large extra dimensions are not immediately falsified by the lack of geological evidence, or by the fact that we don't observe white dwarfs and neutron stars being destroyed by cosmic ray impacts.
To be *worried* about black hole production at the LHC, i.e., to think that it might be dangerous, is a whole different matter. Your criticisms above are all valid criticisms if someone is saying that the black holes might be produced and not immediately evaporate. That requires some very strange nonstandard physics. Here are some papers on the topic: http://arxiv.org/abs/hep-ph/0402168 http://arxiv.org/abs/0808.4087
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It doesn't matter whether the virtual particle falling into the hole is a particle or an antiparticle. (In fact most will probably be photons which are their own antiparticle). The only thing that matters is that the escaping particle has energy. That energy had to come from somewhere. That somewhere would be the black hole itself.
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Shoot a bullet through their material...
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Yeah, I should have written "non-evaporating black holes". Creating them requires all of physics we know to be true, plus some speculative stuff. Preventing them from evaporating requires that precisely the right bits of physics we know to be true, to be false.
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