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Thread: How does this violate the conservation of energy?

  1. #1 How does this violate the conservation of energy? 
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    Hi. I have a hypothetical question / thought experiment that i thought a while ago. I would like to hear your response on the following scenario.

    Suppose we were able to create a hydrogen and anti hydrogen pair from a space station in the very distant future (and seperate it so it doesnt annihilate each other). We then brought the pair down to the surface of the earth via a tube that is able to collect its gravitational kinetic energy with 99.99% efficiency. And suppose we took the hydrogen / anti hydrogen pair we created into a reactor, made it annihilate each other, and converted the gamma energy into electricity with the 99.99% efficiency. Next, we transferred this energy up to space by a superconductor with negligible resistance and assembled it back into the same hydrogen / anti hydrogen pair again. Wouldn't this violate the law of energy conservation?

    I believe this is entirely possible since theoretically Einsteins equation E = MC^2 can be done both ways. Currently, our technology is not advanced enough to convert energy into matter but in the distant future, we may be able to achieve this. However, this process leaves us with the gravitational potential energy that the hydrogen / anti hydrogen gained when it entered the earth. This violates the conservation of energy theory. Can anyone explain why this cannot happen?

    ----------------------------------------------------------------

    I think this may cause some of you into thinking that the energy required to bring the hydrogen pair into orbit requires energy counteracts this situation, but you could instead "beam" the energy up the superconductor into the space station without losing any energy. Additionally, even if you did brought it up by conventional means, repeating this process 2 times will break the law of conservation of energy.


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    Genius Duck Dywyddyr's Avatar
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    Energy losses during the conversion process.
    Energy losses during the transfer process.
    Energy losses during the storage process.

    Did I mention energy losses?


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    Brassica oleracea Strange's Avatar
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    Two things:

    You mention 99.99% efficiency. Therefore there won't be enough energy to recreate the particle/antiparticle pairs.

    Secondly, the gravitational potential energy which you gain by bringing them earth will be "lost" when you take them back up to space (even if you do that losslessly).
    ei incumbit probatio qui dicit, non qui negat
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    Quote Originally Posted by Strange View Post
    Two things:

    You mention 99.99% efficiency. Therefore there won't be enough energy to recreate the particle/antiparticle pairs.

    Secondly, the gravitational potential energy which you gain by bringing them earth will be "lost" when you take them back up to space (even if you do that losslessly).

    I understand that there wont be enough energy to repeat this process indefinitely. But this creates energy out of nothing.

    Could you explain how conducting electricity will be "lost" when we transfer them into space? If you replaced it with light (optical cable) would gravity still affect it?
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    Quote Originally Posted by Dywyddyr View Post
    Energy losses during the conversion process.
    Energy losses during the transfer process.
    Energy losses during the storage process.

    Did I mention energy losses?
    Yes but that loss is converted into heat/sound etc. Nothing magically loses its energy into nothingness.

    For example, a combustion engine may be only 40% efficient but every machine / biological being is 100% efficient into converting energy into heat. The movement of a car dissipates its energy into the tire, the road, and eventually the air. Even sound will be "converted" into heat.

    However, the scenario I mentioned creates more energy than it consumes. How is that possible?
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    Genius Duck Dywyddyr's Avatar
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    Quote Originally Posted by beamthegreat View Post
    but every machine / biological being is 100% efficient into converting energy into heat.
    Huh?
    If that were true then machines/ biological beings would produce NOTHING BUT heat.

    However, the scenario I mentioned creates more energy than it consumes.
    No it doesn't.

    How is that possible?
    By ignoring reality.
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  8. #7  
    Brassica oleracea Strange's Avatar
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    Quote Originally Posted by beamthegreat View Post
    Could you explain how conducting electricity will be "lost" when to transfer them into space? If you replaced it with light (optical cable) would gravity still affect it?
    The photons will be red-shifted as they climb out of the gravity well. See the Pound-Rebka experiment, for example.
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    ei incumbit probatio qui dicit, non qui negat
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  9. #8  
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    Quote Originally Posted by Dywyddyr View Post
    Quote Originally Posted by beamthegreat View Post
    but every machine / biological being is 100% efficient into converting energy into heat.
    Huh?
    If that were true then machines/ biological beings would produce NOTHING BUT heat.

    However, the scenario I mentioned creates more energy than it consumes.
    No it doesn't.

    How is that possible?
    By ignoring reality.
    No, if you think about it, everything will eventually become converted into heat.

    Even if a muscle is 100% efficient into converting energy into movement, the movement WILL eventually be converted into heat in some way or another.

    If it does not, simply lifting an object up will violate the law of thermodynamics. If you lift a 50 kg object up 1 meter and hold it for a hour, it is obvious that you will consume more energy compared to lifting it up for 1 second. The potential energy of the object is exactly the same upon releasing it (50*9.8*1 around 500 joules), therefore the energy you spent holding the object up MUST be dissipated as heat.

    No it doesn't.
    Let me simplify it for you.

    Suppose creating 1 gram of hydrogen/anti hydrogen pair requires 100 terawatts worth of energy.

    We beamed this up via a laser that has an efficiency of almost 100%

    Once we created this pair we made it "fall" down a vacuum tube that collects the kinetic energy once it reaches earth's surface.
    Say this creates 100 kilowatts worth of energy.

    We then annihilate this hydrogen pair inside a reactor that collects its energy which should be close to 100 terawatts.

    We beamed this energy up again and repeat the process.

    As you can see we created 100 terawatts + 100 kilowatts worth of energy. However, the energy required to create another hydrogen pair of the same mass is 100 terawatts. Therefore, we are left with 100 kilowatts. Repeating this process 2 times will create us with 200 kilowatts and so on.
    Last edited by beamthegreat; March 18th, 2013 at 05:25 AM.
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    Genius Duck Dywyddyr's Avatar
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    Quote Originally Posted by beamthegreat View Post
    No, if you think about it, everything will eventually become converted into heat.
    Since, for example, movement occurs, or growth (added mass) then 100% doesn't happen.

    Even if a muscle is 100% efficient into converting energy into movement, the movement WILL eventually be converted into heat in some way or another.
    See above.

    If it does not, simply lifting an object up will violate the law of thermodynamics. If you lift a 50 kg object up 1 meter and hold it for a hour, you will consume more energy that if you lift it up for 1 second. The potential energy of the object is still the same however, therefore the energy you spent is dissipated as heat.
    Er, some of the energy goes into actually lifting the weight.
    And the PE increases.
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by beamthegreat View Post
    Could you explain how conducting electricity will be "lost" when to transfer them into space? If you replaced it with light (optical cable) would gravity still affect it?
    The photons will be red-shifted as they climb out of the gravity well. See the Pound-Rebka experiment, for example.
    Oh that explains everything. Thanks. I presume the same applies for electrons?
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    Er, some of the energy goes into actually lifting the weight.
    And the PE increases.
    Yes but upon releasing the object the energy will still be released. The energy is simply "stored" in this case. It cannot disappear forever (but it might be able to become stored forever).

    Since, for example, movement occurs, or growth (added mass) then 100% doesn't happen.
    Yes, like i stated before, it is simply "Stored" inside our body it will be released once we die and decompose/ or if we are set ablaze.
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    Quote Originally Posted by beamthegreat View Post
    Er, some of the energy goes into actually lifting the weight.
    And the PE increases.
    Yes but upon releasing the object the energy will still be released. The energy is simply "stored" in this case. It cannot disappear forever (but it might be able to become stored forever).

    Since, for example, movement occurs, or growth (added mass) then 100% doesn't happen.
    Yes, like i stated before, it is simply "Stored" inside our body it will be released once we die and decompose/ or if we are set ablaze.
    You are hammering a round peg into a square hole.
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