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Thread: Vacuum Energy

  1. #1
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    Vacuum Energy

    Is the concept of vacuum energy drives feasible?

  2. #2
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    ... No.

    The vacuum has no energy at all. The energy comes from other sources..

  3. #3
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    Try the Wiki article here: http://en.wikipedia.org/wiki/Vacuum_energy. Good luck trying to figure out what they are saying. If it's there, it doesn't seem to be accessible.

    Regards, John M.
    I'm not a hardnosed mainstreamer; I just like the observations, theories, predictions, and results to match.

    "Mainstream isnít a faith system. It is a verified body of work that must be taken into account if you wish to add to that body of work, or if you want to change the conclusions of that body of work." - korjik

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    ?

    Try the Wiki article here: http://en.wikipedia.org/wiki/Vacuum_energy. Good luck trying to figure out what they are saying. If it's there, it doesn't seem to be accessible.

    Regards, John M.
    I'm not a hardnosed mainstreamer; I just like the observations, theories, predictions, and results to match.

    "Mainstream isnít a faith system. It is a verified body of work that must be taken into account if you wish to add to that body of work, or if you want to change the conclusions of that body of work." - korjik

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    Vacuum energy, that is, not the Wiki article.

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    I will not go all soft and give a ounce on this rubbish.. Study that Wiki page and from it understand.

    That placement of metal plates in a vacuum proved the distortion of space and shows the action of 'gravity' upon mass.

    To assert vacuum energy is a abhorrent nonsense. Clutching at false hope.. Please show me I am wrong ?

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    Quote Originally Posted by astromark View Post
    To assert vacuum energy is a abhorrent nonsense.
    Mainstream physics seems to disagree with you about the "abhorrent nonsens." Natura horror vacui indeed.
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    In the particle picture it arises from the uncertainty of time-energy measurements, similar to position-momentum measurements. In the wave picture it arises from the notion of distance in space-time. The problem is that to for quantum mechanics to agree with relativity, we must admit a small but positive minimum energy at every point in space. That is, the discretization of the Hamiltonian of the wavefunction of a relativistic harmonic oscillator gives a non-zero zero-point energy. If we add up all the energy in any subspace, we get infinity. This is seen as a failure of the theories to accurately describe nature, since the contribution of the zero-point field can be measured on macro-scales.

    However, since the vaccuum energy describes the total minimum energy of the system, you can't get any energy out of it. Trying to pull energy from the zero-point field is like trying to ride a hang-glider sitting in your garage. There's just nowhere to go.

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    Quote Originally Posted by tusenfem View Post
    Mainstream physics seems to disagree with you about the "abhorrent nonsens." Natura horror vacui indeed.
    and that just proves my point.. the missing energy is called dark energy..

    and please do not quote in a lat,. script.. I am not the least impressed.. If you had a argument, you just lost it., and me.

    If your vacuum has energy it is not a vacuum. I suggest you read Mr Hawkings.

    Even he said its a mistake to conclude energy when no particle can be found. Something is there.

    Is it just energy.

    Maybe the answer is in the math's.. can you get something from nothing ?

    Nature shrinks back from a vacuum may not be the whole picture.

    My statement rings true.. A vacuum has no energy to extract.

    Any energy component measured is from other inputs and errors.

    and I suspect your little Latin is a breach of your own rules..

    and.. I return to add.. I agree 100% with 'Andrew D'.

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    Well, we have used the Casmir effect to extract some vacuum energy. Issue is that it cost us more to reset the system than we got back. I'm personally highly dubious about using the vacuum as a free energy source because if this were possible on a large scale it would imply that the vacuum state is not a true vacuum. My suspicion is that any use of vacuum energy is going to basically involve artificially generating an area with a false lower vacuum expectation value. That requires energy to come from somewhere!

    But to answer your question more specifically I think more details are needed - the term vacuum drive could mean a range of things, really.

    And Astromark - don't care how much you stamp your foot, the vacuum solution to QM has a non-zero expectgation value and we have measured its effects (which so far don't match theory well, but hey ho). It was not gravity in the thin plate experiments. You seem to be taking a very classical definition of the vacuum - which is fine, but by your definition there is no such thing as a vacuum out there. There is such a thing as a quantum vacuum and it has an energy associated with it.

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    Quote Originally Posted by astromark View Post
    and that just proves my point.. the missing energy is called dark energy..
    I think you are very mistaken there.

    Quote Originally Posted by astromark View Post
    and please do not quote in a lat,. script.. I am not the least impressed.. If you had a argument, you just lost it., and me.
    That is just a historic physics quote, "nature abhors emptiness" and actually I made a mistake, it is "natura abhorret vacuum" claimed by Aristotle.
    All comments made in red are moderator comments. Please, read the rules of the forum here and read the additional rules for ATM, and for conspiracy theories. If you think a post is inappropriate, don't comment on it in thread but report it using the /!\ button in the lower left corner of each message. But most of all, have fun!

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    It appears to me that 'Shaula' has comprehended my objection well.. and that is my view of it..

    To take this argument up to a higher level. Find out by what mechanism does the Universe expand and ...

    Now thats a vacuum. I would turn to mathematics to find the energy potential.

    That there is a answer as yet unfound is apparent.

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    Quote Originally Posted by Andrew D View Post
    ...If we add up all the energy in any subspace, we get infinity. This is seen as a failure....
    Doesn't that seem a lot like the ultraviolet catastrophe? Why can't somebody figure this out?

    Quote Originally Posted by Andrew D View Post
    Trying to pull energy from the zero-point field is like trying to ride a hang-glider sitting in your garage. There's just nowhere to go.
    Do you have experimental evidence of this?
    Everyone is entitled to his own opinion, but not his own facts.

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    Quote Originally Posted by Cougar View Post
    Doesn't that seem a lot like the ultraviolet catastrophe? Why can't somebody figure this out?
    Not really, the UV catastrophe stems from the inability of classical physics to describe what is ultimately a quantum phenomena, thermal radiation. To solve that problem, a "law" of classical physics was found to be incomplete, and was corrected- in a way that pointed toward quantization of energy. The vacuum energy arises because of the restrictions we place on a quantum field theory to make it agree with the axioms of relativity in the first place. The good news is that vacuum energy is emergent from properties that are predicted by both theories and are measurable, so it will probably serve as a guide toward a more compete description of nature.

    I was discussing going into quantum field theory with one of my professors and he told me not to bother: my energy would be better spent going into algebraic topology (specifically cohomology theory), which is where physics is headed.

    Do you have experimental evidence of this?
    Yes, the theory has been completely established and was experimentally verified by this fellow around the time of the first tests of general relativity.

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    Quote Originally Posted by astromark View Post
    I would turn to mathematics to find the energy potential.
    The energy potential is zero, that's why it's referred to as the the 'zero-point energy'. Since relativistic energy is measured in reference to the energy of some other coordinate frame and no frame is preferred, it doesn't really matter that the ground energy is non-zero, kind of like a heat engine doesn't need a 0o K heat sink to do work; it just cant do anymore work once the heat source and sink are in thermal equilibrium.

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    Quote Originally Posted by astromark View Post
    .. and that is my view of it..
    Can you explain your views for us, please ? Seeing as you have such strong ones, I gather there's a strong reason .. so Ö ??

    Quote Originally Posted by astromark
    To take this argument up to a higher level. Find out by what mechanism does the Universe expand and ...

    Now thats a vacuum. I would turn to mathematics to find the energy potential.

    That there is a answer as yet unfound is apparent.
    Really ? How is it apparent ? Could you please explain your perspective for us ?

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    Quote Originally Posted by Andrew D View Post
    The energy potential is zero, that's why it's referred to as the the 'zero-point energy'. Since relativistic energy is measured in reference to the energy of some other coordinate frame and no frame is preferred, it doesn't really matter that the ground energy is non-zero
    Let me get this straight: the ground energy of zero-point energy is non-zero because it is in a different frame of reference than the (rest of the) universe? Or at least, that would be the GR explanation?

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    Quote Originally Posted by noncryptic View Post
    Let me get this straight: the ground energy of zero-point energy is non-zero because it is in a different frame of reference than the (rest of the) universe? Or at least, that would be the GR explanation?
    Zero point energy is fundamentally a quantum effect - I am not sure where Andrew D is coming from on the GR angle. Maybe I am behind the times but as far as I know GR has not been unified with QM at this level. GR permits a cosmological constant and it is hoped that vacuum energy will account for this but so far I have never seen a proof of this.

    Zero point energy is the expectation value of the Hamiltonian - we can artificially create pockets of space where this is lower than the norm (by excluding some of the fluctuations we would normally see) and grab some energy from that but it is more a case or getting back some of the energy we used to create the system.

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    Quote Originally Posted by noncryptic View Post
    Let me get this straight: the ground energy of zero-point energy is non-zero because it is in a different frame of reference than the (rest of the) universe? Or at least, that would be the GR explanation?
    The origin of zero point energy goes back to Planck (and Einstein) who were working on the correct formula for the radiation distribution of atomic 'oscillators' . They realized that each oscillator retained an energy of 1/2 hf ....(where f is the oscillator frerquency) even at zero TEMPERATURE... thus "zero point energy"
    IOWs, there is always a resdual energy in all atomic systems in the amount of 1/2 the quantum. Yes, Einstein worked on the origins of quantum (with Otto Stern)... (Remember Einstein got the Nobel for photo-electric effect, not for Relativity Theory.

    Zero point energy was first experimentally verified in the vibrational spectra of gases in the 1920"s (not sure of exact date) by a fellow named Robert Mullikin. (Spelling? )
    It turns out to be quite ubiquitous in all atomic systems, and is responsible for many physical properties we see in chemical physics.

    Later in Quantum Electrodynamics (and QFT) the source of this zero point energy was attributable to the electromagnetic vacuum fluctuations...as per HUP, etc.

    Only later was its applicability extended to cosmological situations...
    However, as Shaula has said...its origin is quantum in nature.

    G^2

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    Quote Originally Posted by astromark View Post
    It appears to me that 'Shaula' has comprehended my objection well.. and that is my view of it..

    To take this argument up to a higher level. Find out by what mechanism does the Universe expand and ...

    Now thats a vacuum. I would turn to mathematics to find the energy potential.

    That there is a answer as yet unfound is apparent.
    -----

    And a few expect me to explain in detail my view of this... and that answer is NOT available.. to me.

    I do not know by what force is this measured and accelerating expansion driven.. I do not know.

    Not knowing how to answer the question does not eliminate the question.

    We talk of vacuum energy, and do not know what it is. We can measure it. Calculate its real.

    Work with it making expectations found as true.. But explain it.. No, I can not.

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    Work with it making expectations found as true.. But explain it.. No, I can not.
    It drops out of the equations of QM. That is really all the explantion science can give - just like GR does not explain gravity outside its own model of gravity, QM does not explain what vacuum energy 'is' outside QM. G^2 gives a good explanation of what it is in QM. In QFT it is the expectation value of the lowest energy configuration possible (the vacuum). Like it or not these are scientific explanations. You may feel they are unsatifying - but that is the basic truth of it. Scientific explanations are related to the models they are derived from. The ones given here do explain vacuum energy.

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    My rule of thumb for all physics.
    "Everything wants to roll downhill."

    My physics education was only to an engineering level, but I soon realised that all the laws (at least at the newtonian level and basic electrical theory) were just the same rule rewritten. Everything want to go down hill. Laws of thermodynamics, electricity, motion are just the same thing rewritten to say "It wants to go down hill."

    Accessing energy is all about systems wanting to reach equillibrium.

    Apply this to vacuum energy. It may posses massive ammounts of energy, but there is no hill for it to roll down. What system of equillibrium are you going to upset to make something flow out of the vacuum?

    What is the down hill slope you are going to create to make the vacuum energy go lower?

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    Quote Originally Posted by wiggy View Post
    Accessing energy is all about systems wanting to reach equillibrium.
    Apply this to vacuum energy.
    I don't think we want to do that. Then you're talking about a vacuum metastability event.
    Everyone is entitled to his own opinion, but not his own facts.

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    Quote Originally Posted by astromark View Post
    I suggest you read Mr Hawkings.
    Is that the famous hybrid scientist made from Richard Dawkins and Stephen Hawking?

    Flippancy aside, if you're going to appeal to authority in an attempt to put someone down, at least get the authority's name right.

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    Quote Originally Posted by noncryptic View Post
    Let me get this straight: the ground energy of zero-point energy is non-zero because it is in a different frame of reference than the (rest of the) universe? Or at least, that would be the GR explanation?
    That would seem to imply a preferred frame where the vacuum energy is zero. As far as I understand it, the energy is non-zero in the rest (comoving) frame. The GR explanation is the vacuum energy is included in the cosmological constant term, but I think that's more of a "this is the only place we can fit this" explanation.

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    Quote Originally Posted by Shaula View Post
    [...] GR permits a cosmological constant and it is hoped that vacuum energy will account for this but so far I have never seen a proof of this.
    This is what I was referring to as far as how the problem is dealt with in GR. I think we may want to start at understanding the difference between a theory which is a consistent combination of QM and GR and a "relativistic quantum field theory".

    I think what both theories are telling us is that conservation laws don't hold locally.

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