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Method for storing infinite energy?

  1. Jul 10, 2010 #1
    The title sounds impossible and that is exactly what I presume this idea is which is why I am here... I thought of this the other night and it should be impossible but I am not sure which of the many "laws" which collectively tell us there is no such thing as a free lunch prohibit this from working. To clarify: This is just conjecture like Maxwell's demon or Schrodinger's (only much less clever I am sure)... I am not suggesting such a thing could ever be practically constructed...

    I'll start with my assumptions that way someone can give me a quick answer if I am simply starting with a wrong assumption:

    Accelerting an object that has mass to the speed of light would require infinite energy.
    Any energy used in setting an object in motion reletive to another could be recovered by stopping the movment... Ie. coil used to move a magnet could also recover energy by stopping the magnet.
    Black holes have an event horizon inside of which the escape velocity exceeds c.
    Black holes evaporate over time if they are small enough that their "tempature" is higher than the cosmic background radiation (assuming no other "stuff" added to them).

    So... Lets assume some advanced race were to desire a means for storing a great deal of energy.
    They take a black hole having a mass that puts its tempature just a tiny bit above the cosmic background radiation (thus it evaporates but not very quickly... This would be about as massive as the moon and have a diameter of about .1mm IIRC).
    Then they take a particle (or large number of particles) and set them orbiting around the black hole.
    Then they begin adding mass to the black hole... Not enough to make it quit evaporating and start growing but enough to expand the event horizon closer to the orbiting particles.
    At the same time they add mass to the black hole they begin increasing the speed of the particles orbit using remote means (such as magnetic fields if the particles are ferrous but I am sure other means are available). The increase in speed is enough to prevent the particle's orbit from decaying as a result of the increased mass but NOT enough to cause them to fly away...
    See where I am going with this yet?

    What is to stop them from increasing the mass of the black hole and increasing the speed of the particles orbit until the particle have reached, for example, 99.9999999% the speed of light and are just on the edge of the event horizon? Once they have done this the particles have a great deal of potential energy (depending on their mass which would obviously be quite small given the problems with the gradient of the black hole that would arise if they were large).
    Now if this hypothetical being were to want to recover a portion of their substaintial energy investment they could allow the black hole to evaporate while slowing the speed of this particle thus recovering energy from it. In this way could arbitary amounts of energy not be stored? And if so how is this possible? Energy and mass are equivelent and this particle or group of particles would have more mass the more energy you stored (reletively speaking... Things become more massive as they appoarch C) so it ok there but the wierd thing is the volume... It would be a device with a finite volume but capable of storing arbitrary amounts of energy? This makes no sense...

    What am I missing?

  2. jcsd
  3. Jul 10, 2010 #2
    Bodies in orbit are constantly falling towards the center. You'd have to continuously provide energy just to keep the particles orbiting, regardless of any other part of your argument. This energy would be lost, not stored.

    I don't know anything about black holes, so I don't understand the rest of your device anyway.
  4. Jul 10, 2010 #3
    Why would you have to supply energy to keep the particles orbiting? Things orbit earth without a constant supply of energy... The moom comes to mind.

    Of course their orbit would eventually decay by losses of some sort (running into other particles that were still in there becase of imperfect vacuum for example) but this amount of energy would be comparitively tiny and this device (like any other storage mechanism) would not be lossless.
  5. Jul 10, 2010 #4
    Thoughts? This question is irritating me... Soon I will head down to the local university and corner a physicist.
  6. Jul 11, 2010 #5

    Why do you have a problem with it?
  7. Jul 11, 2010 #6
    Energy and mass are equivalent. That means that any form of energy posesses gravity.
    So the potential energy of the orbiting particles would add to the mass of the black hole and enlarge it's event horizon. If there is an infinite amount of energy stored in that thing then its event horizon will be infinite as well.
  8. Jul 11, 2010 #7
    It makes my brain want to explode.

    Energy and mass are equivelent so how can you store infinite mass in finite volume? Also would it really begin to have infinite mass as the particles orbital velocity approached c? I guess they would be going that speed from the frame of reference of anything other than other particles orbiting in the same way.
  9. Jul 11, 2010 #8
    Any time you try to assume an infinite anything you will get a nonsense conclusion.

    Infinity is a mathematical abstraction. Although you can use mathematics to model particular aspects of the universe, it doesn't work the other way round.

    The universe doesn't contain any infinite quantities.
  10. Jul 11, 2010 #9
    So essentially there is nothing preventing one from doing this aside from the inconvinient consequences of having the newly infinite mass object destroy the universe?

    Seriously though their is no way to GET infinite energy to add to the "battery" but you could add a very large amount...

    Too bad it requires a black hole as massive as the moon to work... Unless of course you you were to somehow put the crap comming off the event horizon of a smaller one ("orphaned" halfs of a virtual particle pair IIRC) BACK into it... This might be hard since a really small black hole would give off "crap" at a rate exceeding a nuclear weapon.
  11. Jul 11, 2010 #10
    Doesn't the volume increase when the energy/mass increases? That doesn't sound very paradoxical. Am I missing something?

    A small side-note: you assumed you could make the mass of the orbiting particles small enough as to not 'disturb' the black hole (right?) but if you're pumping (A LOT OF) energy into them and -as you say- E = mc², you can't really make that assumption, can you? But I don't know how important the assumption is, but just thought I might note it.
  12. Jul 11, 2010 #11
    The volume would increase but only slightly up until the event horizon was touching the orbit of the particles (at which point they would need to have infinite energy to remain in orbit). This increase in volume would not be proportional to the increase in mass.

    Regarding your side note: Not sure what could happen to the black hole? I tend to think of them as the universe's only indestructable objects... I suppose if the mass orbiting it truely did become infinite I suppose it might be damaged or disturbed but as we have already discussed putting in infinite energy is impossible... Any real amount of energy would not effect the black hole in any substaintive way (although if only a single particle were orbiting their oribit would be more mutual as opposed to one orbitting the other once the mass of the particle increased to the point where it became close to equal that of the black hole).
  13. Jul 11, 2010 #12
    Not to be a dark cloud, but the energy required to detect, get to, and deal with that type of a black hole under those circumstances likely far, far, far, outweighs any benefit.
  14. Jul 11, 2010 #13
    Of course... This is simply a hypothetical conversation. A battery that weighs anywhere from about as much as the moon to infinity depending on how much energy you put in it is not at the top of anyones list of most desired inventions anyway no matter what kind of capacity it may have. Incidentally though: Considering the rather specific mass you would need the black hole to have it would almost have to be created using artificial means (you would be hard pressed to find one EXACTLY that size).
  15. Jul 12, 2010 #14
    A particle orbiting close to the event horizon would increase the size of the black hole. If it has an infinite amount of energy the black hole would become infinitely large.
    It won't have a finite size.
  16. Jul 12, 2010 #15


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    Do you really need anything so exotic? It seems to me a simple flywheel can store arbitrary amounts of energy. Spin faster, store more energy.
  17. Jul 12, 2010 #16


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    And it will fly apart - just beyond its design speed. What would you make it of?
  18. Jul 12, 2010 #17


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    I have no idea; he was talking about manipulating black holes and spinning particles around it so I thought we were in idealized physics land, not real world. :D

    He seemed surprised that you could store "arbitrary amounts of energy" in a finite package and was talking about evaporating black holes and event horizons and other stuff like that. But the formula for kinetic energy (1/2 * mv^2) makes it quite easy to put "arbitrary amounts of energy" into any finite mass: make it go a lot faster. Particles around a black hole, flywheel, speeding bullet train, it's all the same thing, no?

    In particular, making tiny particles go really, really close to the speed of light, to quote the OP: "99.9999999% the speed of light" seems like a tough way to go to store "arbitrary amounts of energy". The http://www.fourmilab.ch/documents/OhMyGodParticle/" [Broken] was a proton going even faster than "99.9999999% the speed of light" (it was going 99.99999999999999999999951% of the speed of light), and had enough energy to light a light bulb for about a second. So I think a flywheel would probably be more practical :)
    Last edited by a moderator: May 4, 2017
  19. Jul 13, 2010 #18


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    My point was that Energy is involved, even in the construction of a 'flywheel'. The binding energies, keeping it together, would need to be 'arbitrarily high' so . . . .

    My Grandad used to ask me what would happen when an unstoppable force met an immovable object. None of these questions are worth losing too much sleep over.
  20. Jul 13, 2010 #19

    Thanks for that link.
    Last edited by a moderator: May 4, 2017
  21. Jul 13, 2010 #20
    The flywheel idea is used in electrical generation... Big drums spun to 300,000rpm.

    However it would have a finite speed and VERY limited energy storage capacity compared to even a small amount of energy stored in the black hole "battery" (ie an amount that DOESN'T increase its gravity to the point where it consumes everything in the universe)
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