Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Zero-point energy - a question for you all.

  1. Aug 17, 2004 #1
    I have a question about Zero-Point energy. I know that is occurs due to the Casimir Effect which is a product of putting two metal plates very close together, so that large wavelengths of background radiation cannot exist in between the plates. The result is a EM vacuum that excludes some wavelengths and sucks in others. My question is, how close must the plates be? And what wavelengths get sucked in as a result of the vacuum and why? Also, how much enery in Joules or Watts does this theoretically produce and does the distance between plates dictate the amout of output energy? One last question is, what are the plates made of, aluminum, cadmium, tin?

    Please enlighten me, I know there are some closet geniuses posting here, now would be a good time to show yourselves.

  2. jcsd
  3. Aug 17, 2004 #2


    User Avatar
    Staff Emeritus
    Gold Member
    Dearly Missed

    The plates in the experiments are like a tenth of a millimeter apart. Since the distance apart is supposed to block the longer wavelengths, and thus result in a sparser distribution of wavelengths between than outside, it is dependent on those wavelengths, which are after all, quantum things. I have never seen how the enthusiasts could scale this to larger dimensions, and I don't think I've ever seen one of them explain that point.
  4. Aug 17, 2004 #3
    [The Casimir effect occurs due to the ZPE and not the other way around, and the use of the word background radiation is not at all correct.]

    Theoretically: The force on two plates of area A a distance L apart is: [tex]\frac{\pi hcA}{480L^4}[/tex]. But because the distance between the two plates has to be very small to produce a noticable effect, the power you can produce is very small. And if you want to use the plates again aftwerwards you have to put in the same amount of work.

    I don't think wavelengths get 'sucked in', but certain wavelengths do not 'fit' between the plates and produce a pressure because there is a larger energy density outside than in between the plates.

    With the formula you can calculate for yourself how close they have to be to produce the desired force. With the formula for work you can easily calculate the produced power.
  5. Aug 17, 2004 #4
    hmm, so what is you put 2 large metal plates together that close to each other but in a box shape, and put something/someone inside, would they not be able to hear any of whats going on outside?
  6. Aug 17, 2004 #5


    User Avatar

    Staff: Mentor

    The Casimir effect causes a force between the plates, not an energy. There is no energy output of this experiment.
  7. Aug 17, 2004 #6
    No one has mentioned the quantum harmonic oscillator yet?
  8. Aug 17, 2004 #7

    If a force is caused between the two plates, isn't this energy in of itself? How can a force carry no energy? Please explain.
  9. Aug 17, 2004 #8

    Please explain the quantum harmonic oscillator and its link to ZPE and the casimir effect.

  10. Aug 17, 2004 #9
    da willem,

    You are awesome. Many people beat around the bush and do not explain things in the scientific dictum that we should all use instead of philosophical and vague terms. Thanks a bunch. Also that formula is very useful, and proves you have substance behind your words. Keep posting good information, and correct me if I'm wrong about somethings in your kind non-egoic manner. I am very receptive, please teach me.

    Thx again.
  11. Aug 18, 2004 #10


    http://www.lerc.nasa.gov/WWW/PAO/images/warp/warp31.gif [Broken]

    http://www.lerc.nasa.gov/WWW/PAO/html/warp/possible.htm [Broken]

    Use http://wc0.worldcrossing.com/WebX?126@197.AfToc9DKy8e.0@.1dde3fdf [Broken] and type in ZPE
    Last edited by a moderator: May 1, 2017
  12. Aug 18, 2004 #11
    This topic is about the Casimir effect and ZPE as in the vacuum fluctuation energy, not as in the lowest energy of a harmonic oscillator. So the first few of your quotes and links are not of any relevance here.
  13. Aug 18, 2004 #12


    User Avatar

    Staff: Mentor

    Force and energy are two different things. When you stand on a scale, you exert a constant force on the scale and it exerts a constant force on you. No energy is exchanged. Energy requires motion.

    Energy is force times distance times time.
    Last edited: Aug 18, 2004
  14. Aug 18, 2004 #13
    I guess he means the power generated when the plates move together under the influence of the Casimir force. Good luck making energy out of the Casimir force though...!! :biggrin:
  15. Aug 18, 2004 #14
    You obviously need to read more :smile: How do you think the vacuum is being described?

    If you accept this basis, and the background dependance, then you would understand this is a necessary comprehension.

    There are other ways to explain the dynamics as well?
    Last edited: Aug 18, 2004
  16. Aug 18, 2004 #15
    Sol, da willem, and others

    Thx. everyone, sorry for the typos da willem, I meant to compliment you in the first sentence but it was incorrectly written. :)

    Question: Sol points out that ZPE is what's left over when you take out all matter and energy from space (I assume this means taking out the CBE of 2.73Kelvin). My question then is this: How does one extract ZPE? Isn't ZPE averaged out to zero since it is equal part matter and anti-matter? So then, how do we separate matter and anti-matter from eachother before they annihilate each other, so that we can use either of them singly as energy?

    Also, I have heard of one of Hawking's conjectures that says a Blackhole does not violate the conservation of energy law, because as it sucks in matter and light, it spews some out. The spewing, is a result of the fact that matter/anti-matter pairs that happen to be straddling the Event horizon go their separate ways (half of the pair falls into the black hole, and the other half is radiated away from the black hole. And in this manner the black hole radiates the same amount of energy as it absorbs. If this is not explained well, feel free to help me polish it.

    I must admit ZPE troubles me. For if we are extracting energy from the Casimir effect's use of ZPE, where is the antithesis of the energy we extract going?
  17. Aug 18, 2004 #16


    User Avatar

    Staff: Mentor

    Like I said, you cannot extract energy from the Casimir effect. So there isn't any 1st law issue.
  18. Aug 19, 2004 #17


    User Avatar
    Science Advisor
    Gold Member

    It takes more energy to bring the plates together than you could ever hope to extract from the attractive force... entropy 1, casimir 0. What part of the only way to extract energy is to drop it from a higher energy state to a lower energy state do you not understand? Pardon my insolence.
    Last edited: Aug 19, 2004
  19. Aug 19, 2004 #18


    User Avatar
    Science Advisor
    Gold Member

    Apologies to russ, he said the same thing more elegantly than I.
  20. Aug 19, 2004 #19


    User Avatar
    Science Advisor
    Gold Member

    Apologies to all. My comments were out of order.
  21. Aug 19, 2004 #20
    I am listening as well to Russ. It is up to me to explain myself as I am trying to gather my thoughts here.

    Part of the paradigmal change is to recognize that the "whole package/sphere" is encapsulate in a geometrical tendency. Part of this recognition is to undertand what the universe is doing.

    http://universe.gsfc.nasa.gov/images/lifecycles/cycles.jpg [Broken]

    So we define this vacuum within context of Em considerations. Here gaussian interpretations, allow us to consider non-euclidean views? Now what does this mean :smile:

    If we understand the furthest extreme of the plank epoch as one extension of our views of this universe(it's origins) and we look at where we are today, one needs a way in which to interpet these actions "overall"?

    How can these two functions(total energy/ smallest matter-think particle reductionism)+(current universe state, weak field measures) coexist, in the efforts of todays world and know that the exchange, the flow from one state to another is a very flunctuation presence even within the overall view of this cosmo. You have to remember what you include here.

    Wihout hesitation, I quickly draw your attention to the smooth flowing expansion of the cosmos.

    So by looking back to the origins of our universe how could such a supersymmetrical state define for us one extreme, and out of this is born, the worlds we know now around us. It's varying fluctuations?

    What is the one "supersymmetrical state" that allows us to speak to symmetry?

    Answer "this" and you will understand to include this view of co-existance, and the dynamics in ways you had not expected to before. You look at curvature parameters and undertand that these are states of explanations of the varying context of one, or many forms, within the context of this overall universe? Yet the whole process is encapsuated and is topologically driven by how we percieve with our measures?. :smile:

    From this point, geometrodynamcis becomes very revealling, in that topological movement, is the continous nature readily transferable within the context of this co-existance.

    If you do not accept the background dependance, there is no possible way for you to accept this view. If you settle for less then this, then you will find yourself limited to SRian approaches and it attempts at redefintion. The acceptance of GR as it is and the move to define the basis of this reality asks one to consider the whole picture, including the supersymmetrical realization of what arose from the planck epoch. There is a geometrical basis that allows for consistancy? Do we know what that is?

    I am saying that such "views" had to arise from how we interpret the reality in the way I am explaining, and for some who are versed, it will become apparent that such maths that arise had to arise from a co existing well versed universe. And from this, the geometry of consciousness? :smile:
    Last edited by a moderator: May 1, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook