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British Scientists Reverse Casimir Effect

Posted by CmdrTaco on Mon Aug 06, 2007 07:31 AM
from the where's-my-hover-car dept.
Science
An anonymous reader writes "The Telegraph reports that Scientists at the University of St. Andrews have developed a technique to cause the Casimir effect to repel instead of attract. This discovery could lead to near frictionless machines or in theory even levitation."
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British Scientists Reverse Casimir Effect 50 Comments More /

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  • wait... (Score:4, Insightful)

    by flanker (12275) on Monday August 06 2007, @07:34AM (#20128893)
    Isn't it "repel" rather than "repeal"?

  • Oh no! (Score:5, Funny)

    by Anonymous Coward on Monday August 06 2007, @07:34AM (#20128895)
    Gasp, that means we will have to repel one of the laws of seance.

  • Repeal instead of attract. (Score:5, Funny)

    by Dystopian Rebel (714995) on Monday August 06 2007, @07:35AM (#20128905) Journal
    This could be put to immediate use in the USA, where much bad legislation needs to be repealed and they need to attract fewer blockheads to a career in politics.

  • casmir (Score:5, Funny)

    by edittard (805475) on Monday August 06 2007, @07:36AM (#20128915)
    I'm not a big fan of knitwear at the best of times.

  • repeal vs. repel (Score:4, Informative)

    by Laebshade (643478) <laebshade@gmail.com> on Monday August 06 2007, @07:38AM (#20128925)
    It's "repel" as in "the body odor of submitter repels women worldwide", as opposed (heh) to repeal, which means, "to remove or reverse a law".

  • Using the force? (Score:5, Funny)

    by therufus (677843) on Monday August 06 2007, @07:45AM (#20128979)

    Micro or nano machines could run smoother and with less or no friction at all if one can manipulate the force.
    Obi-Wan was right after all! I can become a Jedi!

    So was it only me that heard Sir Alec Guinness read that line out?

  • Not a high point in science journalism (Score:4, Informative)

    by Mathinker (909784) on Monday August 06 2007, @07:46AM (#20128981) Journal
    The discovery is not to be belittled, but both the article and the poster somehow forget to mention that the "levitation" which is talked about is on the order of nanometers (check the Wikipedia article on the Casimir effect). Far from the kinds of stuff you see stage magicians do.

  • And the Casimir effect is... (Score:5, Informative)

    by Mike1024 (184871) on Monday August 06 2007, @07:48AM (#20128997)
    Wikipedia [wikipedia.org]:

    In physics, the Casimir effect or Casimir-Polder force is a physical force exerted between separate objects, which is due to neither charge, gravity, nor the exchange of particles, but instead is due to resonance of all-pervasive energy fields in the intervening space between the objects. [...] Since the strength of the force falls off rapidly with distance it is only measurable when the distance between the objects is extremely small. On a submicron scale, this force becomes so strong that it becomes the dominant force between uncharged conductors. Indeed at separations of 10 nm -- about a hundred times the typical size of an atom -- the Casimir effect produces the equivalent of 1 atmosphere of pressure (101.3 kPa).

  • Requires a perfect lens (Score:5, Informative)

    by PIPBoy3000 (619296) on Monday August 06 2007, @07:49AM (#20129007)
    From this article [zpenergy.com]:

    Now, Leonhardt and Philbin have calculated that the Casimir force between two conducting plates can turn from being attractive to repulsive if a "perfect" lens is sandwiched between them. A perfect lens can focus an image with a resolution that is not restricted by the wavelength of light. Such a lens could be made from a metamaterial made of artificial structures that are engineered to have negative index of refraction -- which means that the metamaterial bends light in the opposite direction to an ordinary material.

    According to the researchers, the negative-index metamaterial is able to modify the zero-point oscillations in the gap between the surfaces, reversing the direction of the Casimir force. Indeed, the researchers believe that this repulsive force is strong enough to levitate an aluminium mirror that is 500nm thick, causing it to hover above a perfect lens placed over a conducting plate. Since the Casimir force acts on the length scale of nanomachines, manipulating it could be important for future applications of nanotechnology.
    To summarize, nothing has been built yet. It's possible that it could be built, though you'd have to make a "perfect" lens in the tiny space between the two plates. Unfortunately, every "perfect" lens I've heard of tends to be wavelength-specific and relatively large (compared to the gap the Casimir effect requires). It may be that these are just engineering hurdles, but it may also be physically impossible to pull off.

  • huh? (Score:5, Funny)

    by apodyopsis (1048476) on Monday August 06 2007, @07:50AM (#20129019)
    What is this? a spelling contest or a discussion about a new scientific discovery?

    Sheesh. Anybody would think /. is populated purely by obsessive pedants with nothing better to do.

    oh..
  • "dry glue" effect that enables a gecko to walk across a ceiling.

    "Spider-pig, Spider-pig,
    Does whatever a Spider-pig does."

  • Casimir Scientists' Own Page (Score:5, Informative)

    by Doc Ruby (173196) on Monday August 06 2007, @08:05AM (#20129131) Homepage Journal
    A humorous page about these British scientists' work by St Andrews physics Professor Leonhardt explains their work on Casimir "levitation" [st-andrews.ac.uk].

  • Being British... (Score:4, Insightful)

    by clickclickdrone (964164) on Monday August 06 2007, @08:07AM (#20129139) Homepage
    1. Invent/discover something cool
    2. Tell everyone about it
    3. ???? 4. NO Profit

    It's sad to say that here in the UK we never learn and have a long and distinguished history of brilliant research followed by total fumbling of the ball and making no money out of the discoveries whatsoever.

    • Re:Being British... (Score:4, Insightful)

      by Pecisk (688001) on Monday August 06 2007, @08:53AM (#20129459)
      And this is bad because...?

      Woah, you want to tell me that there are scientists who actually do science for...err...sake of science, not money? What a surprise!

      Without irony, I personally don't believe in profiting from BIG discoveries. If you get some applications going from that discovery, then it is understandable that you can and you will profit from them, but not from discovery itself.

    • Re:Being British... (Score:5, Insightful)

      by Chief Camel Breeder (1015017) on Monday August 06 2007, @09:18AM (#20129645)

      From the researcher's point of view:

      1. Discover something cool.
      2. Publish results in peer-reviewed journal and get famous.
      3. Get better research job (or more money, security in current one).
      4. Profit!

      Step 3 doesn't have to involve selling technology.

  • an almost content-free article (Score:4, Insightful)

    by petes_PoV (912422) on Monday August 06 2007, @08:10AM (#20129165)
    Apart from saying it uses a "special lens" there's no information about how the team managed to reverse this effect. In fact there's more space given to the hocus-pocus aspects (that every straight thinking /.'er dismissed in an instant) than of any actual science.

    The thelegraph is supposed to be one of the more serious british dailies. So heaven help us all if this is what they pass off as a science story.

  • Slam Dunk Reporting, Guys (Score:5, Informative)

    by TychoCelchuuu (835690) on Monday August 06 2007, @08:23AM (#20129233) Journal
    You can tell the journalistic standards at the Telegraph are through the roof. From the article:

    The force is due to neither electrical charge or gravity, for example, but the fluctuations in all-pervasive energy fields in the intervening empty space between the objects and is one reason atoms stick together, also explaining a dry glue effect that enables a gecko to walk across a ceiling.

    This wasn't enough for me, so I wandered over to Wikipedia:

    In physics, the Casimir effect or Casimir-Polder force is a physical force exerted between separate objects, which is due to neither charge, gravity, nor the exchange of particles, but instead is due to resonance of all-pervasive energy fields in the intervening space between the objects.

    The only changes to the Wikipedia article lately have been a link to this article, which is sort of meta. Wikipedia linking to an article plagiarizing from, of all places, Wikipedia. Cute, but also a little sad.
  • I am a physicist, but these subjects are often beyond me. Still, let me try a short explanation. This seems, to me, rather an important discovery.

    The Casimir effect happens when you get two surfaces very nearly touching. Virtual particles emerge on the other side of the surfaces and force them together. Virtual particles being, well, virtual -- very short-lived and low-energy -- this effect only occurs when the surfaces are very, very close to one another.

    What's intriguing about the Casimir effect is that it is extracting work from the zero point energy of the universe, the base energy field of empty space. (Yes, even a total vacuum contains virtual particles, and thus some energy.) It is not immediately obvious how to make this useful, however, if the only way to tap into the zero point energy is to destructively sandwich two expensive materials together.

    Reversing the Casimir effect is brilliant. By placing a perfect lens between the two materials, the virtual particles create a repulsive force. This could, as stated, create a levitation effect by preventing the surfaces from ever touching. 'Levitation' is a strong word, though. It'll 'levitate' a nanometer or so above the other surface, which is only good for reducing the friction between them to zero. So 'frictionless surfaces' is probably the keyword we should be using here.

    I'm intrigued because it would seem to be easier to generate power from the zero point energy with a repulsive effect than an attractive one. So this could also be the first step toward a zero point energy generator -- free energy. What will they think of next...
        • The energy isn't created really, is kept from moving into the area between the plates.

          Let me explain further:

          Heisenberg's uncertainty principle says you can't know where a particle is, or it's momentum, at the same time. That applies to space too. For any point in space, you can't know if there's a particle there or not.

          Therefore, the reality is that the vacuum is boiling all the time with particles popping into and out of existence all the time. Particle soup. For another interesting effect of this, check out Hawking radiation.

          Anyway, if the plates are close enough together, no particles can be popping into existence in that space, because it's too small. It's literally small enough that if there were a particle there, you'd know it's position and momentum, and that is NOT allowed.

          So, the situation you've set up is that you have two plates very close together, with particles appearing and disappearing on one side of the plates (the outside surfaces) but not on the inside surfaces. That means that there's a pressure created which forces the plates together.

          No energy is created because what you're doing is preventing particles (energy) from appearing inside the plates. The energy of a vacuum is not zero because of those particles. The energy inside the plates is zero (zero point energy).

          The problem is that once the plates have moved together which is work, you don't get any more work out of the system unless you move the plates back apart.

  • Their discovery could ultimately lead to frictionless micro-machines with moving parts that levitate.
    Finally that fast talking dude will have a job again!

  • In Theory (Score:5, Funny)

    by j00r0m4nc3r (959816) on Monday August 06 2007, @09:00AM (#20129517)
    I hereby theorize that cramming peanuts into your arsehole will cause levitation.

    There, now that I've officially theorized this, I can say, "In theory, cramming peanuts into your arsehole will cause levitation." and it's perfectly true.

  • Casimir effect allows geckos to walk on ceiling (Score:5, Funny)

    by mrjb (547783) on Monday August 06 2007, @09:12AM (#20129605)
    FTA: "The force is due to neither electrical charge or gravity, for example, but the fluctuations in all-pervasive energy fields in the intervening empty space between the objects and is one reason atoms stick together, also explaining a "dry glue" effect that enables a gecko to walk across a ceiling." ... and now that scientists have figured out how to reverse the Casimir effect, this will soon enable geckos to walk on the floor.

    • Re:ummmm? (Score:5, Informative)

      by IBBoard (1128019) on Monday August 06 2007, @07:41AM (#20128961) Homepage
      The BBC are slightly more useful at http://news.bbc.co.uk/1/hi/scotland/edinburgh_and_ east/6932283.stm [bbc.co.uk] - they say it's a "friction reducing lens". Still doesn't give us a lot to go on, but it's a start!

    • Re:ummmm? (Score:5, Informative)

      by DJ Paradox (219601) on Monday August 06 2007, @07:59AM (#20129075)
      Try checking out the University website - it had much more information about the science of the discovery:

      http://www.st-andrews.ac.uk/~ulf/levitation.html [st-andrews.ac.uk]

      Pity they have a photo of Syndrome and his Zero-Point Energy device as an example at the top. Doesn't help anyone to take them seriously surely.

      • Re:ummmm? (Score:5, Informative)

        by nwhitehorn (1044658) on Monday August 06 2007, @01:44PM (#20132783)
        Here's the paper, courtesy of arXiv:

        http://www.arxiv.org/abs/quant-ph/0608115 [arxiv.org]

        It should be noted that this work is purely theoretical. What they have done is show that there is a much more physically realizable way to way a repulsive Casimir effect than the previous schemes, using a material with negative refraction over some range of important frequencies (this is a similar problem as making a cloaking device, but with a harder range of the spectrum). In practice, the effect would be small and the material hard to make, but the idea is interesting.

    • Re:ummmm? (Score:5, Funny)

      by itsdapead (734413) on Monday August 06 2007, @08:18AM (#20129205)

      im baffled how this works.. any insight?

      I assume it involves a cat with a piece of buttered toast strapped to its back...

      • Re:ummmm? (Score:5, Funny)

        by IBBoard (1128019) on Monday August 06 2007, @09:17AM (#20129639) Homepage
        That would repel from the floor, but not from another cat with another slice of buttered toast strapped to its back (which is what this can potentially do).

        From what I remember of the buttered toast cat, doesn't it end up spinning just above the floor as the cat tries to land feet-first and the toast tries to land butter-side down? If so then why is no-one wrapping these cats in wire, putting them between magnets and throwing them off surfaces en-mass to generate electricity while they spin?

        • Re:ummmm? (Score:4, Funny)

          by 49152 (690909) on Monday August 06 2007, @09:30AM (#20129757)
          Only works with live cats. The cost of feeding and care for the cats makes this uneconomical. ;-)

        • Re:ummmm? (Score:5, Funny)

          by evanbd (210358) on Monday August 06 2007, @10:37AM (#20130659)
          It's all well and good until you have to take the cat down for maintenance. Have you ever seen a cat that's been wrapped in wire, strapped to a piece of buttered toast, and spun for 3 days? Let's just say it's not happy.

        • Re:ummmm? (Score:4, Funny)

          by dmclap (1103635) on Monday August 06 2007, @11:06AM (#20131015)
          Actually, the cat will freeze in midair suspended on its side, because in that case, the direction of spin that requires the least work to get the cat/toast to the correct position are in opposite directions with an equal magnitude. So, sadly, it will hit static equilibrium, so you'll just have a crazy floating cat, not a crazy floating power-generating cat.

      • Re:ummmm? (Score:5, Funny)

        by hypnagogue (700024) on Monday August 06 2007, @11:12AM (#20131081)

        I assume it involves a cat with a piece of buttered toast strapped to its back...
        No, silly! That would be the cat-schmear effect.

    • Casimir Effect Explained (Score:5, Informative)

      by Roger W Moore (538166) on Monday August 06 2007, @10:06AM (#20130203) Journal
      The Casimir effect is very wierd indeed. If you take two metal plates and put them close together in a vacuum they will attract one another VERY weakly. The effect is caused by fluctuations in the electric charge of the vacuum. Think of it a little like sea level. On average if you measure sea level lots of times you wil get "0" for the height but if you measure it just once the height you get will depend on the tide and the size of any waves. The same is true for a vacuum. Look at a particular volume of space and measure the electric charge. On average you will get zero but for a particular moment in time it may be non-zero.

      Ok so far but how do we get an attractive force? Well it turns out that charge must be conserved so if one region of space has a small positive charge at one instant a neighbouring area must have a small negative charge (in quantum terms we say that we pair produce and virtual electron-positron pair) thuse we have a dipole. Now remember the two conductors? Well the one nearest the positive charge will have the electrons in the conductor attracted to it and being a conductor they will move towards it giving the conductor a net negative charge. The opposite will happen in the conductor nearest the negative charged area of space.

      So now we have, instantaneously, a conductor with a negative charge and one with a positive charge...so they attract one another. this is the Casimir effect. If you stop to think about it is is VERY strange because it means that two metal plates in vacuum, with no externally applied fields will attract...so you have to ask yourself what exactly is doing the work i.e. where is the energy coming from to move these plates?

      I'm not a condensed matter guy so I must admit I don't quite understand why this effect is so important to them. I understood that in molecules it was known as Van der Waal forces and due to periodic dipoles occuring in molecules in much the same way it does ina vacuum. Only, because there is a real electric field, the effect is much larger. So if there are any condensed matter people out there perhaps they would like to explain why it is Casimir and not Van der Waals that is important? or is it just because they have the same origin the name Van Der Waals has been dropped?

        • Re:Casimir Effect Explained (Score:5, Informative)

          by Roger W Moore (538166) on Monday August 06 2007, @01:48PM (#20132829) Journal
          I understand how you might think I got the two confused but no, this effect is completely distinct from gravity. It has a different strength, behaves differently and its fundamental mechanism is understood at the quantum level, unlike gravity.

          Also there is actually no evidence whatsoever that gravity and EM fields are interrelated. It is postulated that at around 10^16 GeV they are but there is no evidence for that yet....and just to show you how much faith you should put in theory without concrete evidence to back it up remember that at one time people thought that the Earth was flat!

    • Re:They'd better be careful (Score:5, Informative)

      by Anonymous Coward on Monday August 06 2007, @08:40AM (#20129355)
      I have a masters in physics, and although im not an expert in these things, i believe i have a better working knowledge than parent.

      In the quantum description of the electromagnetic field, there is no such thing as uniformly zero field - even in completely empty space, there are oscilations in the field spread over all modes (ie. wavelengths). It can be compared to an ocean or pond in stormy weather where there will allways be *some* waves.
      Now, if we have a geometry consisting of two flat opposing plates, only certain wavelengths corresponding to the distance between the plates will be allowed. Thus by increasing or decreasing the distance between the plates, we can deside which zero-point wavelengths will be allowed, and it is such that the situation where the plates are very close are energetically favorable, hence we will see the two plates attract each other and this is known as the casimir force which has been measured many times in the experiment. Its important to realize that its not charges on the plates which are doing the work - everything is kept charge neutral. Its vacuum doing work :-) .

      (by manipulating the geometry of the plates, inserting lences, etc. its then theoretically possible to make the plates repel instead, which is what the article is about)

      Anyway. My point is. This is not like nuclear chain reactions. The experimental conditions under which you see these effects are extreme (as in: the truck on the street or the cellphone in the assistants pocket will ruin it). Its a neat discovery, but the doom and gloom is completely uncalled for.

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