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Negative energy

  1. Oct 8, 2009 #1
    What is meant by total negative energy associated with bound bodies like planets. and also total energy of the hydrogen atom is negative. I wonder how it could be? Because I believe whatever negative energy may be, It must only be associated with bound systems, and I don't think that an isolated H-atom (as what we assume during its derivation) is bound to anything. Finally how it differs from negative energy associated with warm holes?
  2. jcsd
  3. Oct 8, 2009 #2
    In classical mechanics the zero point of energy is arbitrary - and consequently the distinction between positive and negative energy is arbitrary.

    Recall a ball near the surface of the earth has potential energy approximately m*g*h (m=mass, g=acceleration due to gravity=9.8m/s^2, h=height). Where do we measure the height from? The ground? The center of the earth? The table the ball is sitting on?
    It doesn't matter! These will all give different potential energies, but only differences in energy are physical.

    That being said we conventionally for gravity and electrostatics we take the zero of energy as when all the particles are infinitely far from each other (because potential energy drops off as 1/r).

    So for example consider the sun and earth system, this has some negative gravitational potential energy, -E. E is the energy that would be released in moving the Earth from infinitely far away (through free space) to its current distance from the sun.
    Conversely E is the energy that would be required to push the Earth out of the sun's influence.

    Now consider an isolated H-atom - it is a bounded system. The electron is bound to the proton! (In a very similar way to how the Earth is bound to the Sun). What you would call the total energy is the energy released when we add an electron to a proton to make Hydrogen. Conversely it is the energy required to rip an electron away from the hydrogen atom.

    I have no idea what a warm hole is, but I assume it's a whole different kettle of fish.
  4. Oct 9, 2009 #3
    Thank You for yours reply.
    In general relativity there are three type of extreme bodies, theoratically predicted. One is black hole which you already know, second is white hole in which nothing can ever fall and hence "white" & third is warm hole, which has some properties which allow time travel. Theorist like THOMAS A. ROMAN and LAWRENCE H. FORD have predicted that to create a warm hole we will require negative energy which is different from negative energy mentioned above.
    and read article Negative Energy, Wormholes and Warp Drive.
    Last edited by a moderator: Apr 24, 2017
  5. Oct 9, 2009 #4
    energy is neither created nor destoyed. it merely moves from place to place and changes form. think of energy as being like water. we can move it from place to place and freeze or evaporiate it but the total amount remains the same. when measuring the level of wtater in a lake we can assign any number we want to any given level of water. if we assign a positive number to one level then it entirely possible that later the watter may drop to a level where we need negative numbers to describe it. but the water itself is always positive. there are no negative sheep and there is no negative water. the exception is energy stored in gravitational fields. this energy (and no other) is inherently negative. it has to be for the total energy of a gravitationally bound system to be conserved. energy stored in other kinds of fields is positive.
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