Follow Slashdot stories on Twitter

 


Forgot your password?
Close
typodupeerror
×
Education Math Science

Hawking Radiation Claimed Created In a Lab 129

Posted by CmdrTaco from the look-what-i-can-do dept.
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.'"
This discussion has been archived. No new comments can be posted.

Hawking Radiation Claimed Created In a Lab More

Hawking Radiation Claimed Created In a Lab

Comments Filter:

  • LHC will not kill us all! Future research... (Score:3, Interesting)

    by Luyseyal ( 3154 ) <swaters@NoSpAM.luy.info> on Monday September 27, 2010 @09:38AM (#33710358) Homepage

    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

    • Re: (Score:1, Redundant)

      by Luyseyal ( 3154 )

      Furthermore, I dub it a "Hawking battery" or "Hawking capacitor" if it ever comes to pass!

      -l

      • "Furthermore, I dub it a "Hawking battery" or "Hawking capacitor" if it ever comes to pass!"

        Too late, and don't you dare. I've trademarked and patented both.

    • You might want to create black holes. I'm sure you could imagine using them as an energy source... (just have to be a bit careful they don't over eat, if you know what I mean.)

      • Re: (Score:2)

        by hitmark ( 640295 )

        As if fusion power was not hard enough to get up and running...

        • At the rate the fusion researchers are progressing, creating black holes (accidentally at first) and using them for power might be quicker...

  • Double emission? (Score:4, Interesting)

    by FalconZero ( 607567 ) * <FalconZero&Gmail,com> on Monday September 27, 2010 @09:45AM (#33710432)
    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?

    • Re:Double emission? (Score:5, Informative)

      by cb123 ( 1530513 ) on Monday September 27, 2010 @09:57AM (#33710542)
      Popular visualizations and even the notion of "virtual particles" do not allow very accurate reasoning with regards to Hawking radiation. In particular, the "promotion process" from "virtual" to "real" is just a crutch for proving something to all orders in perturbation theory. Shortly after Hawking-Bekenstein, Bill Unruh proved that simply being in a uniformly accelerated reference frame creates a perception of thermal background radiation coming from the background -- at a temperature equivalent to the pseudo-event horizon of the acceleration for the duration of the acceleration. You see, while if you move at a constant rate any photon will catch you just as quickly as if you were standing still (basic special relativity) if instead you accelerate forever, you asymptotically approach the speed of light, but there are photons far enough behind you that will never catch you. How far behind they need to be depends on how fast you are accelerating. So, every acceleration corresponds to a pseudo event horizon. As soon as one stops accelerating the photons can catch up to you. Unruh's result does *not* depend on the permanence of the horizon, but works for temporary accelerations. So, the horizon does not need to be "permanent" for the "promotion" to occur. A better way to think about Hawking radiation is any gravitation field (any curved space, that is) decaying via thermal radiation, or space itself providing some "resistance to acceleration" or intrinsic acceleration-only viscosity where the energy taken away from the acceleration is converted to thermal radiation. The image of a virtual pair around an event horizon is not, ultimately, how the result holds or is proven or even what the process is "about". It's more like an "inspiration to a derivation" than something to be taken so literally.

      • Re: (Score:3, Interesting)

        by tgrigsby ( 164308 )

        So by your explanation, I give off Hawking radiation just by walking across the room? My understanding of Hawking radiation had to do with more of a shearing effect caused by extreme gravitational conditions parting two virtual particles to result in a single real particle. I'm not sure my ass qualifies as a sufficiently large gravitational well, nor can I picture a pseudo event horizon forming at any distance behind it while I walk.

        • Re: (Score:2, Informative)

          by cb123 ( 1530513 )
          Yes, if Hawking's idea about black hole radiation is true, all gravity fields should radiate. Without even walking across the room you create thermal radiation at a fantastically small temperature no matter how small your ass is, just by virtue of your tiny gravitational field. There is no "sufficiently large gravity well" to generate the radiation, only sufficiently large to generate *measurable* radiation.

          In the case of black holes, the radiation of stellar or galactic mass singularities is absolutely

          • So much for using humor to make a point...

            There comes a point where the rubber must hit the road, and in your case I believe the problem you're having is a lack of proof. Thermal radiation is not Hawking radiation, and Hawking radiation, as opposed to evaporation, should not only be more "noticeable" for tiny black holes, it also becomes more "noticeable" for black holes traveling at relativistic speeds or with an extremely high spin, according to the theory. As for the "imagined scenario", it's imagined

      • Re: (Score:3, Interesting)

        by Thing 1 ( 178996 )

        The image of a virtual pair around an event horizon is not, ultimately, how the result holds or is proven or even what the process is "about".

        I had the mental image of myself walking, shedding heat particles, generated by my internal processes cracking apart ATP, and using the gained energy inside (in order to walk). It was pretty cool, "self as event horizon", with particles splitting (if you allow the definition somewhat loosely, with "energy" and "heat" being what's split). Also appreciated Unruh bein

    • Re: (Score:2)

      by c0lo ( 1497653 )
      TFA doesn't seem quite a novelty [st-andrews.ac.uk] - even more, the linked article contains some nice layman-term explanations, including how to create a white-hole in the kitchen sink; this may help you to guess an answer on what could happen when you shut close the tap (errr... what happens when the horizon collapses).
  • 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.

  • Interesting related first observation (Score:3, Interesting)

    by pinkushun ( 1467193 ) on Monday September 27, 2010 @09:56AM (#33710534) Journal

    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 [st-andrews.ac.uk]

  • 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.

    • Re:Magrathea (Score:5, Funny)

      by dkleinsc ( 563838 ) on Monday September 27, 2010 @10:11AM (#33710674) Homepage

      Well, to get a proper explanation of 'white holes', we really need to go to the experts:

      Cat: So, what is it?
      Kryten: I've never seen one before - no one has - but I'm guessing it's a white hole.
      Rimmer: A *white* hole?
      Kryten: Every action has an equal and opposite reaction. A black hole sucks time and matter out of the Universe; a white hole returns it.
      Lister: So, that thing's spewing time ... back into the Universe?
      Kryten: Precisely. That's why we're experiencing these curious time phenomena on board.
      Cat: So, what is it?
      Kryten: I've never seen one before - no one has - but I'm guessing it's a white hole.
      Rimmer: A *white* hole?
      Kryten: Every action has an equal and opposite reaction. A black hole sucks time and matter out of the Universe; a white hole returns it.
      Lister: So, that thing's spewing time ... back into the Universe?
      Kryten: Precisely. That's why we're experiencing these curious time phenomena on board.
      Lister: What time phenomena?
      Kryten: Like just then, when time repeated itself.
      Cat: So, what is it?
      [Kryten, Rimmer, and Lister stare at Cat]
      Cat: Only joking.

  • 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

    • Put the black hole in an empty box. The particles that escape the event horizon will eventually find their way out of the box, i.e. radiation comes out of the box.

      Because of energy conservation, the contents of the box must loose energy and thus mass. Since there is nothing in the box except a black hole, it must loose mass.

      • Re: (Score:2)

        by vlm ( 69642 )

        Because of energy conservation, the contents of the box must loose energy and thus mass. Since there is nothing in the box except a black hole, it must loose mass.

        I think whats missing is the energy transport mechanism. Convection (whats circulating, certainly nothing from inside the event horizon...) Conduction (touch the event horizon and fly away?) Radiation (the hot surface is inside the event horizon so light can't escape, right?)

        Saying the energy transport mechanism is magic is no better than saying energy does not have to be magically conserved in that environment.

        • Re: (Score:3, Interesting)

          by cb123 ( 1530513 )
          The process need not actually be distributed over space -- the escaping particle travels, yes, but the actual energy conversion happens when and where the escaping is first created.

          Now, its creation is a quantum state transition which has a "magical" quality in the same way that, say, a photon escaping an atom's electron shell does. There is no extended energy transport process at all. The electron makes a quantum jump simultaneously with the photon field of the world gaining a new photon traveling awa

      • Because of spelling cnservatin yur pst caused mine t lse all f its letter 's.

    • Re: (Score:3, Informative)

      by cb123 ( 1530513 )
      The responder has it right. You are missing that the virtual pair has no net energy initially and one escapes. So, the outside world is getting heavier and the black hole lighter - to conserve total system energy. You are thinking of the "virtual" counterpart as having mass, but it does not. It's "virtual".

      As I mentioned above, one does not need a black hole for this -- all curved space should release thermal energy, though the rate is usually immeasurably small. Google Unruh effect and read about it

      • 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 rele

    • Re: (Score:1, Informative)

      by Anonymous Coward

      What you are missing is the laws of thermodynamics, where the universe ends up trying to "balance the books" in terms of mass and energy. Steven Hawking proposed this concept based upon the laws of thermodynamics in a broad sense, where mass and energy are always conserved.

      In this case you can think of the particle falling into the event horizon from the virtual pairs as a sort of "negative mass". I know that isn't completely accurate from a pure physics perspective, but it is sufficient for mere mortals

    • Re: (Score:2)

      by Bengie ( 1121981 )

      My understanding is that the hole has gravity. The gravity is doing work on matter surrounding the hole and/or else where in the universe as gravity extends out to infinity. Work requires energy. Mass and energy are the same.

      When the hole does work outside of itself via gravity, it loses mass/energy and will eventually disapear.

      I have a question regarding micro blackholes that someone may help me with. Lets say you have your two protons in the LHC smash into eachother. A bunch of energy/mass is given off as

      • Would this micro black hole even be able to consume a particle if it's forced to interact with the particle as a wave because of its size?

        Yes, but it would have a very small collision cross section for an electron, for example. This means that it would have a low probability of "consuming" any particular particle it encountered. This why a such a micro black hole would take billions of years to consume the Earth even if it were stable and was gravitationally captured.

  • Fry Hole. (Score:2, Funny)

    by SeNtM ( 965176 )
    "I call it a Hawking Hole."
  • 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).

  • Graviton Diode? (Score:3, Interesting)

    by Doc Ruby ( 173196 ) on Monday September 27, 2010 @10:16AM (#33710746) Homepage Journal

    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?

    • And then the Quantum Police in their Quantum Speedtrap give us a ticket for violating the speed limit.

      I wonder what they take payment in...

    • Re: (Score:2)

      by Samah ( 729132 )
      I lost you at "could".

  • what are the practical applications for the real world? How will this help prevent our extinction?

    • what are the practical applications for the real world? How will this help prevent our extinction?

      Easy. Before our extinction by blackhole impact we apply our knowledge on blackhole dissipation and dissolve it.

  • 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 per

  • 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.

  • Coincidence? I think not. (Score:1, Insightful)

    by Anonymous Coward

    Isn't it a bit too coincidental that a guy named Stephen Hawking would discover something called Hawking radiation. I call BS.

  • Event Horizon (Score:3, Funny)

    by Yvan256 ( 722131 ) on Monday September 27, 2010 @11:01AM (#33711372) Homepage Journal

    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."

  • 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?

  • Probably not hawking radiation. (Score:5, Informative)

    by SETIGuy ( 33768 ) on Monday September 27, 2010 @11:44AM (#33712166) Homepage

    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.

    • Re: (Score:3, Funny)

      by DriedClexler ( 814907 )

      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.

      Yeah, and you know what's even worse? Some assholes report the mass of fundamental particles using electron-Volts which is a unit of *energy*, not mass. Retards.

      • Re: (Score:2)

        by smaddox ( 928261 )

        Most likely they meant eV/c^2. This is a standard units used for mass of elementary particles (by physicists). Since E=mc^2, and eV is a measure of energy, eV/c^2 is a measure of mass.

        In these units, the electron has a rest mass of 511 KeV/c^2.

        • Re: (Score:2, Informative)

          by tendays ( 890391 )
          I'm afraid you got wooosh-ed, my friend.

          • Re: (Score:3, Interesting)

            by DriedClexler ( 814907 )

            I love that this is a site where I can tell, and people can get, jokes that require you to see the analogy between quoting an EM frequency as a wavelength, and quoting a mass as an energy. Makes my day :-)

            • It's a bad analogy. Frequency and wavelength are inverses. Mass and energy are equivalents.

            • Re: (Score:2)

              by SETIGuy ( 33768 )
              A mass is an energy and vice versa. A wavelength is not a frequency, nor is there a constant relation between them They are not equivalents. There is no analogy to anyone that comprehends math and physics.
      • It is hard to tell if you are being sarcastic, but eV is a unit of mass when you set c=1, which makes mass=energy. Particle physicists do all of the time to make the calculations easier. It is a problem of getting used to the notation and lingo.

      • Re: (Score:2)

        by SETIGuy ( 33768 )

        Or retards that can't see that 1055 nm doesn't have units compatible with frequency. A change of one word (frequency to wavelength) makes it correct. 0.0009478 nm^-1 could work, but that's not a frequency, it's a wave number.

        Just because something is convertible doesn't make it a proper measuring unit for the quantity being stated. If you start giving "frequencies" in eV, m^2 or dyne second/gram (all of which could be converted) people are going to think you're an idiot and, in the sciences, they cert

  • The other day I was clearing debris from a fenceline. I turned over a rotten log to reveal a termite nest. I watched for a moment as the panicked insects scurried about with their larvae and such, then kicked their home aside and went about my business.

    This is what First Contact will be like for us. If we're lucky. Note that I didn't bother to exterminate the critters.

  • 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.

  • 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.

    • Re: (Score:2)

      by fishexe ( 168879 )

      ...and somebody later named in Hawking Radiation.

      "named it", rather. Way to shoot my own comment in the foot.

Slashdot Top Deals

Two can Live as Cheaply as One for Half as Long. -- Howard Kandel

Close