Circa 2012
Faraday and Dirac constructed magnetic monopoles using the practical and mathematical tools available to them. Now physicists have engineered effective monopoles by combining modern optics with nanotechnology. Part matter and part light, these magnetic monopoles travel at unprecedented speeds.
In classical physics (as every student should know) there are no sources or sinks of magnetic field, and hence no magnetic monopoles. Even so, a tight bundle of magnetic flux — such as that created by a long string of magnetic dipoles — has an apparent source or sink at its end. If we map the lines of force with a plotting compass, we think we see a magnetic monopole as our compass cannot enter the region of dense flux. In 1,821 Michael Faraday constructed an effective monopole of this sort by floating a long thin bar magnet upright in a bowl of mercury, with the lower end tethered and the upper end free to move like a monopole in the horizontal plane.
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