[AntonioLao]

Constant electric field does not produce magnetism vice versa. Maxwell's equations are for changing electric field and changing magnetic field. However, if electric charges are moving with constant velocity then we get current as well as magnetism as in electrical power transmission but no electromagnetic radiation. Electromagnetic radiation such as light or radio wave requires acceleration or oscillation of electric charge density in antenna. The radius vector is the spacetime displacement.

[Guille]

Originally Posted by AntonioLao Constant electric field does not produce magnetism vice versa. Maxwell's equations are for changing electric field and changing magnetic field. However, if electric charges are moving with constant velocity then we get current as well as magnetism as in electrical power transmission but no electromagnetic radiation. Electromagnetic radiation such as light or radio wave requires acceleration or oscillation of electric charge density in antenna. The radius vector is the spacetime displacement.

Yes, and you said in your previosu post that it was the variation electric fields, isn't that the same as chaning electric fields?

Now I see, the difference between electromagnetic radiation and electromagnetic fields.

[AntonioLao]

Originally Posted by GUILLE variation electric fields, isn't that the same as chaning electric fields?

electromagnetism is a good example of a local gauge invariant vector field.

[Guille]

Originally Posted by AntonioLao electromagnetism is a good example of a local gauge invariant vector field.

hummm.... Thanks. By the way, the latex equation you posted didn't appear (in the other post you did).

Now, today the physics teacher has explained us how electricity and magnetism actually come from the same thing. And that magnetism is the bipolar domains caused by the angular momentum and spin of electrons, and he told us how these get parallelized. So we got quite a big enlightment today. But, the actual thing is that I myself with no help discovered where magnetism and electricity come froma nd why it is called electromagnetism. And it wasn't by reading thorugh maxwell's equations: I derived it my self from a pair of experiments I did. I wanted to know why everyone said electromagnetism as if it where one thing, and I did. Now, coming back to the theme, does the fact that we magnetize when we are awake and move impply that kinetic energy + potential energy is equal to magnetism?

[AntonioLao]

Originally Posted by GUILLE kinetic energy + potential energy is equal to magnetism?

For an isolated system, the sum of of kinetic and potential energy is a constant independent of time or magnetism. Although a human being is not an isolated system by strict definition, its body temperature is a constant (98.6F) for everyone big or small, fat or thin, young or old.

[mkirkpatrick]

The need to sleep,and to demagnetize,serves two purposes I feel,one is the outer need,the purely physical.and then there is the inner need to defragment
to recharge the mind,and reassign data to the brains memory chips!

kind regards michael.