What is all this electromagnetic stuff, anyway ? |
Since ancient time, philosophers, scientists and poets have wondered what our physical reality actually consists of. It turns out that nearly all aspects of our apparent physical existence are manifestations of electromagnetic forces and energies. This electromagnetic force is what gives material objects the illusion of solidity even though they are composed of 99.999% empty space. When a hammer strikes a nail, the actual protons, neutrons and electrons dont touch each other, it is the electromagnetic force fields of the hammer and the nail that bang together. The latent force of electromagnetism may be mathematically described by a field of vectors, hence the term force field.
Electromagnetic forces are not always tied to particles. They also can propagate as electromagnetic waves, or as photons, according to the fundamental constants of our space-time continuum. Electromagnetic radiation has a dual nature, this duality means sometimes we see the wave-nature and sometimes we see the particle-nature. If we could see the instantaneous amplitude of an electromagnetic wave propagating in two dimensional space-time from a point source, it would look something like ripples propagating on the surface of water :
| Representing a wave propagating in 2 dimensional space from a point source. |
| A is Amplitude | Increasing A increases the strength of the point source |
| B is Attenuation | Increasing B increases the decay rate away from the point |
| C is Frequency | Increasing C increases the frequency (shortens the wavelength) |
By the late 19th century, many scientists had discovered laws of electricity and magnetism now familiar to us; Faraday, Ohm, Ampere, Volta, Franklin and others. James Clerk Maxwell, a young Scottish mathematician, took upon himself to forge these fragments into a set of powerful interlocking equations which totally describe the behavior of the electromagnetic force. Maxwell quickly realized that magnetism, electricity and light were different aspects of the same force discribed by his vector equations. Over a hundred years later, the Maxwell equations are the cornerstone of antenna theory, optics, physical chemistry and lie at the very root of most physical phenomena we perceive. Light, electricity, magnetism, radio, microwaves, x-rays, chemical bonds, combustion, mechanical properties of solids, liquids and gasses and many other physical phenomena are manifestations of the electromagnetic force. It has been well said that all the laws of classical physics may be derived from Maxwells equations.
A controversy still overhangs the Maxwell Equations. The "Maxwell Equations" used today (shown above) are not the originals. Maxwell originally used many equations, including expressions in quaternion mathematics when he correctly proved magnetism and light to be aspects of the same force, in his paper "A Dynamical Theory of the Electromagnetic Field" in October of 1864. The familiar form of four interlocking vector equations used today, in either differential or integral form (above shown in integral form) are actually a simplification developed later by Oliver Heaviside and William Gibbs. Heaviside (of Kennely-Heaviside Layer fame, the original name of the ozone layer or ionosphere) declared his dislike for Maxwell's quaternions, and ridiculed Maxwells notion of magnetic field 'idlers'. Maxwell himself emphasized the idler notion was not to be taken literally, but was necessary for visualizing a valid mathematical concept. Yet the self educated Heaviside stripped Maxwells work of its quaternion terms and reduced it to the four simplified equations used today in the design of things like cellular phones, radar antennas and invisible airplanes.
Some folks, however, believe Maxwells original work taken in its entirety would have unified gravity as well, a theory known as 'electrogravitics' which would indeed have vast implications. Einstein used the simplified Heaviside forms in his Special and his General Theories of Relativity, thus missing the opportunity to unify gravity. Proponents of Electrogravitics hope the missing peices hold the keys to gravity generators, antigravity, gravity-energy conversion and the like.
Modern physicists believe in the existence of four fundamental forces in nature. In order of increasing strength they are: gravitational, weak nuclear, electromagnetic, and strong nuclear forces. It has been shown that the electromagnetic, weak and strong nuclear forces are aspects of the same force, that is, the three strongest forces have been unified mathematically. The holy grail of modern physics is the mathematical unification of all four forces. Establishment physicists believe that at higher energies, a single fundamental force will be shown which acts as four separate forces at lower energies. Big Science experiemnts have unified three forces, but physicists now believe the energy required to unify gravity (the Grand Unification Energy) is beyond anything which could be produced on earth. Physics is now turning to Cosmology, hoping to see clues to the Grand Unification in high energy processes involving black holes, quasars or even the afterglow of the beginning of the universe.
In classical electromagnetics, the four Maxwell equations are expressed in terms of four vectors. They are: electric field, E , electric flux, D , magnetic field H , and magnetic flux, B . The equations are interlinked because each vector force is described in terms of another. The equations are further linked by two continuity conditions.
Maxwell's equations state that when an electric field moves, it creates a magnetic vortex, a kind of swirl or wake in spacetime. Likewise, when a magnetic field moves, it creates an electric vortex. Light, x-rays, radio waves and the like are merely ripples in our spacetime continuum, where the electric and magnetic aspects of the force travel together as electromagnetic waves which propagate at the speed of light.
The top half of this illustration shows how the force field vectors make up a slice of an electromagnetic plane wave which travels in space. The lower half shows how the force field vectors are often simply pictured in amplitude.
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