Asked by: Colin Coulton

In order to generate a magnetic field that can be said to propagate, it is necessary to produce a changing field by turning on an electromagnet or removing a magnet from a magnetic shield such as a superconducting box. Changing magnetic fields are also produced around all radio transmitter antennas due to the changing current flowing in them.

When a magnetic field is changing, it is always accompanied by a transverse electric field, i.e., it is an electromagnetic wave. The relationships between changing magnetic and electric fields are summarized in the well-known Maxwell's equations.

Click here for a more detailed mathematical derivation and description.

The speed of electromagnetic waves is certainly known and is defined to be exactly 299,792,458 m/s in vacuum (same as the speed of light).

Answered by: Scott Wilber, President, ComScire - Quantum World Corporation

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'A theory with mathematical beauty is more likely to be correct than an ugly one that fits some experimental data. God is a mathematician of a very high order, and He used very advanced mathematics in constructing the universe.'**Paul Dirac**

(*1902-1984*)

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