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Negative energy versus positive energy

  1. Jul 14, 2006 #1
    Cancellation or generation of positive energy by negative energy and vice versa is so often brought up by very serious physicists (e.g. A. Guth, A.V. Fillipenko) as the argumentation for the possibility of the generation of our universe out of “nothing”, that I hardly dare to question this. As an example or metaphor for it is most often used the so called cancellation of (so called positive) kinetic energy by the (so called negative) gravitational energy.
    But, to me, energy will never be cancelled it will always be exchanged.
    Let me pose here some (as I hope) clarifying questions:
    1) If one “drops”/puts a massive sphere just in the middle of a pipe which goes straight through the earth from the north-pole to the south-pole, then this sphere will stay at rest and will never get kinetic or gravitational energy.
    2) A harmonic oscillator in static equilibrium will never oscillate as long as no energy is supplied to it.
    3) An electric L-C network not loaded with electric and or magnetic charge will never swing as long as no energy is induced.
    Without the existence of energy (e.g. vacuum energy or ZP energy), I don’t see a reason for generation of anything equivalent to energy. (Intuitively I can’t accept the ”free lunch”).
    To me “nothing”= nonsense. Can anyone explain me the contrary? Where can I find a “proof” (SR, GR, QM, in particle physics experiments, in cosmological observations) or even a clear indication for “nothing”= no nonsense?
    My simple reasoning (too simple?) helps me more than high sophisticated mathematical reasoning in string theory or in LQC (Loop Quantum Cosmology) which theories, I suppose, are only understood by maximum a few thousands, who even don’t always agree among themselves.
    This thread can also be seen as my further contribution to the threads:
    “Singularity or Planck density?”
    “Is a zero universe a consequence from FRLW equations?”
    “What existed before the big bang?”
    “Eternal universe”
    “Multiverse”
    “Inflation”
    I must say that PF is a very valuable source for finding all kinds of ingredients in the many threads so nicely sustained by advisers like Chronos, Garth, Marcus, Space Tiger and many others that maybe this thread is superfluous, but I felt a need to concentrate on just this question.

    Further remarks:
    1) The use of the terms positive and negative, well used in other cases and disciplines, seems to me misused where it concerns energy.
    2) Never understood that Heisenberg’s uncertainty principle was meant to generate energy.
    3) E=mc^2 does not imply that E only means kinetic energy, does it?
     
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  3. Jul 15, 2006 #2

    Jorrie

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    Re: Negative energy...

    As an engineer, I'm certainly not qualified to answer your questions/remarks technically; so just some "practical remarks" to stimulate discussion ::wink:

    My understanding of the "free lunch" is somewhat ‘agricultural’, or shall I rather say 'engineering-like', but here goes. During the inflation epoch, it is possible that energy was extracted from the vacuum and converted into kinetic energy of space expansion, leaving the vacuum with a net negative energy. This negative energy acts as a contracting force, balancing out the positive expansion energy and thus ensuring that Omega = 1. A somewhat more complete "engineer's view" on this can be downloaded from one of my web pages: http://www.einsteins-theory-of-relativity-4engineers.com/friedmann-equation.html
    (The PDF is a draft chapter of a yet-to-be-released ebook on relativity and cosmology for engineers.

    Jorrie
     
  4. Jul 16, 2006 #3

    Chronos

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    The most striking physical example of positive and negative energy is anti matter, which clearly exists. It is therefore logical to treat gravity as a form of negative energy - given it's the only form of energy that literally sucks. It closely parallels magnetism. But, to be fair, I also believe the electroweak force is a low energy, emergent form of gravity. I even have a testable prediction in mind: neutron stars tend to have curiously weak equatorial magnetic fields.
     
    Last edited: Jul 16, 2006
  5. Jul 16, 2006 #4

    Jorrie

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    Anti-matter negative energy?

    :confused: I don't quite understand how anti-matter can be negative energy. Is it not so that to create a positron, one needs 'positive energy'? Further, if the electron and positron meet, are they not annihilating each other with the release of that same amount of positive energy again? If the positron had negative energy, would the net result not have been zero energy?
     
  6. Jul 16, 2006 #5
    Aren't you confusing this with the positive energy / negative energy aspects of virtual-pair particle formation near the event horizon of a black hole (which is interpreted as a negative energy particle falling into the hole while it's positive energy twin escapes in the form of Hawking radiation)?

    In free space, I don't see how any antiparticle can be thought of as "negative energy"?

    All four fundamental forces "suck" as you put it. The concept of gravitational (potential) energy being negative arises from the arbitrary choice of a zero potential energy - obviously any gravitational potential energy below that zero would be negative by definition.

    Best Regards
     
  7. Jul 16, 2006 #6
    Often misunderstood, yes, and where misunderstood then misused.
    The concept of potential energy entails that we define a zero datum for potential energy. It follows that any system below this datum will have (by reference to the datum) a negative potential energy. This is the case for gravitational potential energy. If the PE zero datum is defined at maximal separation for a collection of massive objects then any contraction under mutual gravitational attraction leads to a decrease in gravitational PE (ie it goes negative) but an increase in KE.

    It doesn't, it only says that energy-time is uncertain - ie we can borrow a certain amount of energy from the quantum vacuum for a certain time without violating the HUP. Over significant timescales, however, total energy must be conserved.

    No, it doesn't.

    Best Regards
     
  8. Jul 16, 2006 #7
    The Einstein momentum-energy tensor, T, is equal to the curvature tensor, G. So it might be seen that the positive energy, T, is balanced by the negative energy, G.
     
  9. Jul 17, 2006 #8

    Chronos

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    Hand slaps acknowledged. Anti-matter is obviously not a form of negative energy, so that was definitely a 'duh' moment. The gravity comment was incomplete - it is the only force that is always [so far as is known] attractive. But. yes, it depends on the accounting system as to whether or not you can classify it as 'negative energy'.
     
  10. Jul 17, 2006 #9
    If energy is E=mc^2, energy cannot be negative, and E/m=constant.
    If energy is KE=.5mv^2, energy cannot be negative. Despite that, KE is relative.
    If energy is entropy*temperature, energy cannot be negative. What happens if this kind of energy is constant?

    You can have positive or negative work, but that is dependent on direction.
     
  11. Jul 21, 2006 #10
    Can we (I) conclude or summarize?

    Thank you for your reactions. I will start to make (my) something out of it.

    1) Energy modes are balanced. Calling one mode positive and
    another mode negative can cause misunderstanding and
    misusing.
    2) Not all kind of possible energy are well understood or even
    known especially when they are hidden in the vacuum.
    3) Energy is never created nor destroyed, it is only transformed
    and sometimes it is the vacuum which is the beholder.
    4) Indeed “nothing”= nonsense.
    5) Can it be a reasonable question /hypothesis to assume that
    quantum fluctuations can be transformations of energy modes
    within the vacuum or even between the vacuum and our
    observable universe?
    6) Pre bang’s and an infinity-verse can not be avoided to
    considerate when trying to get more understanding of an
    autonomous reality?
    Kind regards
     
  12. May 4, 2010 #11
    Greetings,
    I stumbled on this old forum thread trough some googleing and im not sure wether to post it here or make a new post thread. So I decided to place it here anyway:shy:.
    I was wondering if you guys could clarify this futher for me, as I never did any study in physics or whatsoever, however this energy stuff does interest me.
    I always thought that everything in the universe is infinite and thus zero.
    ( (1 + (-1)) + (2 + (-2)) + (3 + (-3)) +... = 0 + 0 + 0 + ... = 0)

    Therefore I always thought that matter was positive energy created out of 0.
    However since everything has to be 0 there must be negative energy equal to that of the matter. Since matter takes in space there must be something that takes in negative space,gravity.

    Anti matter is the same as Gravity however this is materilized instead of positive energy making it negative, giving it a positive Gravity.

    It is probably a 50% chance for positive or negative energy to become matter or gravity. But since anti matter rules out matter and visa versa, one will be dominant to the other for as long as they are not isolated.

    Also to anwser who or what created matter, Big Bang, or whatever. I think that since zero and infinity are equal yet also opposites of each other, something bigger must excist something that enshrouds both. I'd like to call that Chaos. Chaos is infinite everything(∞), and all at the same time(0). If that is true everything, this, all of it, simply has to excist.

    I want to apologize for my sucky english (has to be sucky since everthing is red underlined^^), And also if i wasted your time with my simple stupid rambling.
    However if you did read all of it please help me explain that my (yours, ours) thoughts or not simply order trying to understand chaos. Please explain why i am wrong and not simply that i am wrong...
     
  13. May 4, 2010 #12
    I don't mean to be rude, but what are you talking about? Zero and infinity are not the same. Anti-matter is not gravity. Only part of your post that may come under debate is about orderly universe emerging from chaos.
     
  14. May 4, 2010 #13
    Are you saying that my post is false and that you will not or cannot explain why?
    Or that you dont understand what i talked about and that i explained wrong?
    Im confused :(
     
  15. May 7, 2010 #14
    Hawking suggested that there is no edge to spacetime.

     
  16. May 9, 2010 #15
    nothing= no nonsense.

    The universe has a net energy of zero. Matter "exists", but it exists only as a means of describing relationships of things in our observable universe. Everything that we perceive to "exist" is just relationships. If the entire universe is just relationships, then the entire universe is nothing. For example, language is used to describe relationships between matter, yet language is basically nothing. It is but a concept. As is matter. And concepts are nothing.

    Sorry if that was muddled.
     
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