Michel Jullian wrote: >>>> a violation of energy conservation? No. Electric >>>> potential energy is decreasing somewhere, >>>> I'll let you find where :) > ... >> ...We want >> to know, lol! :-) > > Oops I have found in the meantime that my initial explanation was wrong, so it's just as well I kept it to myself ;-)
No problem! > Electric potential energy has nothing to do with the matter as I realized (my apologies for the misleading hint). > Still it seemed obvious to me that _some_ potential energy had to be decreasing, since it takes work to bring > the dipoles back to their non-aligned initial state. Same reasoning as in the non-rotating case where magnets > are just attracted to each other, similar to a mass falling off a table as previously mentioned by Stephen. > This led me to Googling "magnetic potential energy", and bingo, there is such a thing, and it decreases > all right when magnetic dipoles align! > > You'll find a good explanation at the url below, > for the case where one small dipole swivels inside another, larger one (see their > drawing for the geometry). In this simple case no linear motion is involved, just the > rotation to alignment we are concerned with, very much like a compass needle aligns with > the Earth's magnetic field without being pulled as a whole one way or another. > > http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magpot.html : > > "A magnetic dipole moment in a magnetic field will possess potential energy which > depends upon its orientation with respect to the magnetic field. Since magnetic sources > are inherently dipole sources which can be visualized as a current loop with current I > and area A, the energy is usually expressed in terms of the magnetic dipole moment: > > U = -µ . B where µ=IA > > The energy is expressed as a scalar product, and implies that the energy is lowest when > the magnetic moment is aligned with the magnetic field..." > > Therefore if the small magnet swivels without friction it should oscillate like a pendulum > around the aligned position, with energy being similarly transferred back and forth between > potential energy (max at max disalignment) and kinetic energy plus field energy (max at alignment). > Variation of the latter can probably be neglected in the small magnet vs big magnet case, > just like one neglects the complete system's gravitational field energy variation when > deriving the pendulum's motion in the Earth's gravitational field. I mentioned that early on in the discussion that such a dipole oscillates back and forth due to momentum and magnetic attraction until friction dissipates such energy. Although, once again, that is beside the point. The point is energy is coming from something ***while the two dipoles are accelerating angularly***. Below I'll describe the process once again. > Energy conserved in standard physics, unsurprisingly. No, no, no. We're *not* talking about the energy conservation of the dipole oscillating back and forth. We are *not* talking about permanently removing energy from the electron spin. As previously stated, such a process is temporary so long as the dipoles remain magnetically aligned and at their separation distance. Again, consider two magnets initially at rest and magnetically unaligned. The two dipoles then accelerate angularly to magnetic alignment when released, thus gaining KE and an increase in net magnetic field. Did you know that when you apply a magnetic field to magnetic material at curie temperature there is a significant increase in temperature (over 4 C)? When on intensely studies magnetic materials the reason becomes clear as to why. At curie temperature the magnetic dipole moments are for the most part unaligned. When the field is applied the dipoles align. Again, the process of aligning dipoles adds energy. So even the electron gains KE during such a process. We are trying to find the source of that energy. Again, if we *knew* nothing about an electro-magnet or air coil then at best we could merely say, "Oh, well, it's just potential energy. So we can't say which came first." Fortunately we now have technology that indeed reveals that such a process requires energy. We have technology that can create magnetic fields on demand-- the electro-magnet. The electro-magnet clearly reveals that it consumes energy from the current source while the two dipoles are rotating to alignment. Therefore we can no longer nonchalantly ignore and brush off such an issue. Same goes for gravity. Presently we cannot generate a gravity field on demand; i.e., an electro-gravity coil. When a ball is moved upward away from Earth we are adding PE to the system. Presently most physicists just nonchalantly accept the existence of PE, as it's quite possibly out of our reach to understand where that actual potential energy went. Although, lets say we have technology to create an electro-gravity coil. So we're out in free-space and turn on the gravity coil. An object begins accelerating toward the gravity-coil. Since we presently know what happens when we perform such an experiment with an electro-magnet coil and ferromagnetic material, we can theorize the same might happen with an electro-gravity coil, which is acceleration drains energy from the current source that generates such a field. So what is happening is energy is being moved from the electro-magnet device to the accelerating object. Therefore, when we use the magnetic dipole moment of the electron instead of the air coil electro-magnet we once again gain kinetic energy. It appears such energy comes from whatever sustains the electron spin. To blow off such a quest IMHO is foolish, as there is a great deal of valuable potential experiments in regards to such an effect. For example, one could study possible decrease in electron life span during such a process. IOW, perhaps the process of ***temporarily*** draining the source that sustains the electron slightly reduces the lifespan of such an electron. We don't know what will happen. As example, perhaps given present best technology we could influence one electron to self annihilate per week. IOW, such an experiment would resemble the following outline --> Setup: A piece of pure iron material inside a superconducting coil. 1. Apply a 10 T field to iron for 1 ms. 2. Analysis --> Were any electrons annihilated? Repeat experiment if not. Perhaps there's a certain probability of an electron annihilating due to temporarily removing energy from its source. Such an experiment could take minutes, weeks, or perhaps centuries to cause one electron annihilation with present technology. I for one would like to know where such energy comes from. Regards, Paul Lowrance ____________________________________________________________________________________ TV dinner still cooling? Check out "Tonight's Picks" on Yahoo! TV. http://tv.yahoo.com/
