Why don't magnetic monopoles exist?

[NEILS BOHR]

magnetic monopoles??

why don't magnetic monopoles exist??

 

[andonrangelov]

Actually the question can be set in a different way? Do the magnetic monopoles exist?
The last question still do not have answer. The magnetic monoples may or may not exist. If they exist then the magnetic charge should be much, much less then a electric charge due to the fact that the Maxwell equations are tested to high precision and therefore only a very small magnetic charge can exist.
From time to time there are publications that claimed the demonstration of the Dirac monopoles (such as spin ice http://en.wikipedia.org/wiki/Spin_ice) but the real monopoles are not found in Nature yet…..

 

[kcdodd]

The question is even actually slightly more interesting then that. There is what is called a duality transformation for Maxwells equations which can transform E and B into E' and B', and electric charge and current into a mixture of electric charge, current, and also magnetic charges and currents. That is, for example, an electron would be partially an electric monopole and partially a magnetic monopole in the new fields instead of pure electric monopole. It would also then be partially magnetic dipole and electric dipole instead of pure magnetic dipole. So what is important is if the *ratio* of magnetic charge/current to electric charge/current is the same everywhere. If so, then one can conveniently transform away one or the other. Historically, the fields are chosen such that magnetic charge/current = zero.

Duality transformation from Jackson p. 274
$$\vec{E} = \vec{E}'cos(\theta) + Z_0\vec{H}'sin(\theta)$$
$$Z_0\vec{H} = -\vec{E}'sin(\theta) + Z_0\vec{H}'cos(\theta)$$

$$Z_0\vec{D} = Z_0\vec{D}'cos(\theta) + \vec{B}'sin(\theta)$$
$$\vec{B} = -Z_0\vec{D}'sin(\theta) + \vec{B}'cos(\theta)$$

$$Z_0\rho_e = Z_0\rho_e'cos(\theta) + \rho_m'sin(\theta)$$
$$\rho_m = -Z_0\rho_e'sin(\theta) + \rho_m'cos(\theta)$$

$$Z_0\vec{J_e} = Z_0\vec{J_e}'cos(\theta) + \vec{J_m}'sin(\theta)$$
$$\vec{J_m} = -Z_0\vec{J_e}'sin(\theta) + \vec{J_m}'cos(\theta)$$

$$Z_0 = \sqrt{\mu_0/\epsilon_0}$$

Subscripts e or m indicate electric and magnetic sources respectively.

It can be fun to play around with these to come up with different configurations.

 

[santo35]

your question is more philosophical in nature...in science there is a caution in handling a question of "why"...you can't ask "why" questions always...
well y arent they any monopoles.? - god noes !... its like asking y do Newton's laws wroks? or ts like y is force equals m times acceleration... well its good that you started 'thinking' the science way, but do think upon why your question of "why" dosent survive . ah ! dats a pun der ! ;)... check out this on my blog if u have time http://intellectual-discomfort.blogspot.com/2011/01/science-is-questioning-but-wait-what-to.html