Has the speed of propagation of a magnetic force field been measured? If so what is it?
Asked by:
Colin Coulton
Answer
The term magnetic force field implies the application of a force on a distant
object, say a piece of iron, by a magnetic field.
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
'The strength and weakness of physicists is that we believe in what we can measure. And if we can't measure it, then we say it probably doesn't exist. And that closes us off to an enormous amount of phenomena that we may not be able to measure because they only happened once. For example, the Big Bang. ... That's one reason why they scoffed at higher dimensions for so many years. Now we realize that there's no alternative... '