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The sum of all energy in the universe

  1. Aug 4, 2008 #1
    I had this thought as a bit of a lark. an argument to prove the universe does not in fact exist.

    But it leads me to a question. What is the sum total of all energy in the universe?

    Ok what I thought was... a basic tenement in physics is for every action there is an equal and opposite reaction.

    so If I was to push against a wall it pushes back at me with the same level of force. or probably more accurately it resists my push with a resistance equivalent to my push.

    Thus the sum of those forces is zero, my 1f plus the walls -1f ie. 1 + -1 = 0
    (don't worry about me breaking the wall I am not strong enough. And if I did the result is the same except now it includes the ground, air resistance, my leg muscles stopping me from stumbling etc...)

    Now please remember this started as a bit of fun so please don't mock me too much

    Therefore for all force in the universe there is an equal and opposite force acting and thus the sum of all force is zero.

    If the sum of all force in the universe is zero and therefore the sum of all energy in the universe is zero. we could argue the universe does not exist. because all matter is made up of energy.

    So all bullshtting aside what is the sum of all energy in the universe is it zero or some massive figure?

    If it is some massive figure where did it come from?
    If its zero then does the universe exist?

    I am sure someone with a greater grasp of the English language and physics terminology could have written this better but I think it gets across the idea.
  2. jcsd
  3. Aug 4, 2008 #2


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    Zero is a number. It exists.
  4. Aug 4, 2008 #3
    Err don't draw me on that one...

    So are you saying the sum of all energy in the universe is zero?

    If so then that makes sense because before the universe, nothing existed, therefore if the universe was made from nothing it must resolve back to nothing.
  5. Aug 5, 2008 #4
    The sum of all the energy in the Universe should be zero, if the present laws of physics are right.

    HOWEVER, energy CAN be created out of nothing, via quantum fluctuations, because of the energy-time uncertainty principle.

    \Delta E \Delta t \approx \hbar

    The law of conservation of energy CAN be violated, but only for very small amounts of time.
  6. Aug 5, 2008 #5
    I'd say that the sum of ALL energies in the universe IS indeed 0.

    Why we exist, is cause of the imbalance of energy. See, there's a planet at this part of the universe, and no matter at other parts. Mass is energy, hence there is an imbalance.
    So we live... for now. till we meet our anti-matter friend!
  7. Aug 6, 2008 #6
    To Chris
    You have a logical fallacy, You say that since A follows one law then B must also follow the law in the same fashion. Try to avoid using force and energy interchangeably, they aren't synonymous.

    However think about this, Energy, which can be used synonymously with heat, does not need an opposite, my proof goes that a lack of heat is absolute zero. Your argument claims that there must be more then a lack of energy there must be negative energy, however the kelvin scale only hits 0. Most scientists, at least the credible ones agree there isn't negative heat, only a lack of it, or the scale would have negatives.

    Force will always have opposite forces, energy doesn't, Something loses energy and something else gains it, but that isn't the same as the wall pushing back!

    That aside to Tw,
    I believe that there is a significantly less amount of antimatter then matter, mind you I learned this from my high school physics professor, who is a bit of a quack and didn't know his science all that well.
  8. Aug 7, 2008 #7
    "Negative energy" is speculated to exist, it is called exotic matter. (Look up Kip Thorne.) Hypothetically, exotic matter has negative energy and negative mass. Theoretically, for example, by shining a beam of this exotic matter onto a hot body, the hot body will lose energy and cool down. Negative energy is also thought to be responsible for the acceleration of the expansion rate of the Universe, this negative energy we call dark energy.
  9. Aug 7, 2008 #8
    Erm, I'd disagree with the term dark energy being negative energy. Dark energy is energy taken as energy taht causes the expansion of the universe. It is gravitationally repulsive, but it does not have to be negative energy, and may even not consist of negative energy at all.

    Exotic energy is or matter is similarly much wider scope too. It is just matter or energy that are unable to be defined by current means and knowledge, that disobey the characteristics of current ideologies of matter and energy. So exotic matter/energy may consist of negative mass/energy, but there are other possibilities too.
  10. Aug 10, 2008 #9
    Just an unresearched question here:

    Antimatter. Does E=mc^2 apply to it? What is antimatter measured in?
  11. Aug 10, 2008 #10


    Staff: Mentor

    Here is your error. Energy is a scalar quantity, not a vector quantity like force, so you should immediately know that the direction doesn't matter.

    You need to look at the definition of energy (or work) a little more carefully. Let's say that you and the wall interact via some force, where you experience a force f and a displacement of d, while the wall experiences a force -f and a displacement of 0. The work done on you is f.d = E and the work done on the wall is -f.0 = 0. Also, if the wall is displaced, say a distance -d, then the work done on the wall is also -f.-d = E. The dot product is positive definite, so the energy is always greater than or equal to zero regardless of the direction of the force.
  12. Aug 10, 2008 #11
    Completely agreed with DaleSpam. In order for the energy in the universe to be zero, negative energy must exist.
    Hence my question earlier, does antimatter have negative mass?
    Negative energy in E=mc^2 would require a negative mass ;)
  13. Aug 10, 2008 #12


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    Antimatter has positive mass. E=mc^2 applies to it. It just has the opposite charge compared to its matter counterpart.

    Edit: I thought this was well-known but DaleSpam below says it hasn't been demonstrated. Learn something new every day!
  14. Aug 10, 2008 #13


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    Most people think that antimatter has positive mass, but it hasn't been demonstrated yet.
  15. Aug 16, 2008 #14


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    Does that mean we don't know if the positron has a positive mass equal to the electron's one? From wikipedia it says "The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1, a spin of 1/2, and the same mass as an electron." So I've a doubt now.
  16. Sep 22, 2008 #15
    Now, I'm not 100% sure about this, but I think mass has nothing to do with the way electrons and positrons interact. It is known that they both have opposite charges, but I have also been informed that positron has an opposite spin of an electron. The two particles annihalite when they meet (at this point I am also not sure if there has to be a specific angle between their interaction). But the collision of the two produces total annihilation of the particles resulting in two photos (gamma photons) being displaced in opposite direction (possibly perpendicular to the original angle of electron/positron interaction). This is actually the underlying principle behind the PET (Positron Emission Tomography).

    P.S. Also heard that there is about 90% of the 'dark matter' in the universe. The one that can't be readily observed, and accounts for the previously unaccounted mass of the universe (this is from a high school teacher years ago, please don't destroy me if I'm wrong :P)
  17. Sep 22, 2008 #16
    I'm very curious about that last part Spetsop: Who has been measuring the dark matter, and where can I find a conclusion reached for the amount of it in the universe?
  18. Sep 22, 2008 #17
    I'm not exactly sure of it myself, I will research and try to find out more information about it as well. But at the moment I am not sure, as I've stated already it's old information from a high school physics teacher (that was about 6-7 years ago), so it could have, and most likely did change.
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