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Infinite energy and conservation

  1. Sep 27, 2008 #1
    doesnt the fact that a magnet's field going from one end to another perpetually, constitute infinite energy?
    also, dont particles disobey the conservation law because where do particles get their energy from? particles are always moving. they never stop. but why is matter only destroyed if a particle and anti-particle smash into one another? maybe we think they are annhilated, but something else happens. maybe they are converted into something we cant analyze yet and dont know about? dark matter or something???
    doesnt the very fact that matter cant be destroyed-atoms keep going and going, their energy keeps going around in the world, making things move all the time in various ways, and that light photons go on forever, disobey the conservation law because these things shouldnt get their infinite energy from nothing??? since particles and light photons are moving all the time, they should be getting their energy from something.

    sure, matter always changes from one kind to another, but as far as i know, matter is never destroyed. then doesnt that mean things must be getting their energy from something we dont know about? and what about the energy from that? and on and on. and the fact that light particles will keep going and going, even if it is diverted by something, it doesnt stop-it just moves in a different direction. its energy is perpetual. light energy is perpetual. doesnt that violate the conservation law?
  2. jcsd
  3. Sep 27, 2008 #2


    Staff: Mentor

    No, a finite magnetic field has a finite energy density.
    It doesn't take energy to continue to move. That is called inertia.
    They are converted into something we can analyze easily: light.
    Again, it doesn't take energy to continue moving.
    I don't understand your statement here when just above you mentioned matter/anti-matter anhilation.
    No, you just have a small misunderstanding of what energy is and what the conservation of energy means.

    Energy is the capacity to do work. Work is a force times a distance. The conservation of energy basically states that the change in the energy of a body is equal to the work done on the body. If your force is zero your work is zero and so your change in energy is zero regardless of the distance travelled. So a particle in motion does not require extra energy in order to remain in motion because by Newton's first law it does not require any force to remain in motion.
  4. Sep 27, 2008 #3


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    Staff Emeritus
    Science Advisor
    Gold Member

    In fact, the OP should realize that conservation of energy actually explains WHY particles remain in motion in the absence of any external influences. Once a particle has some kinetic energy (which is proportional to the square of its speed), it will continue to move at that speed. It's not just going to suddenly stop...that would mean it had somehow inexplicably lost its kinetic energy and energy conservation would have been violated.
  5. Sep 27, 2008 #4
    but DaleSpam, isnt there constant(infinite) movement of particles in a finite magnetic field?
  6. Sep 27, 2008 #5


    Staff: Mentor

    Again, it doesn't require energy to keep moving at a constant speed.
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