Shufflebrain

Physical theory tells us that light, emitted and absorbed as photons-- as particles--travels as waves, waves of mass-energy. Light is mass-energy in extreme motion (if Einstein was right). Except for the fleeting instant when mass-energy becomes light, or ceases to be light, it is waves. Objects change waves; they warp them. The warp is the optical message, and its specific character depends first of all on what the waves were like just before they illuminated the scene, and, second, on the nature of the objects. If the object indiscriminately absorbs waves of energy, as for example a patch of tar does, its image will appear to us to be dark, because very little light radiates away from it and into the optical environment. If the object has little capacity to absorb energy, as is the case with the fur of an albino mink, say, then light will be warped by contours and edges, but the image will appear white in white light, blue in blue light, red in red light, and so forth. If the object absorbs particular colors or wavelengths, it will subtract those energies from a mixture and will reflect or transmit the rest. White light, which is a mixture of the colors of the rainbow, contains the waves for an infinite variety of hues. The primary colors red, green, and blue, can combine to form the 500,000 or more hues a human eye can discriminate.[1] In addition, objects distort the waves relative to the sharpness, smoothness, or complexity of their contours. But the totality of the optical message travels in the form of a warp.

In all electromagnetic radiation, including light, the shorter the wavelength the greater the energy. Offhand, this may seem wrong. But think of the pleats of an accordion. Compressing the bellows, thereby forcing the pleats together, concentrates the train of wavelets and increases their number per inch. In electromagnetic radiation, likewise, the shorter the wavelength, the greater the frequency , or number of wavelets per second. Also, as wavelength decreases, the amplitude of each wavelet increases: the peaks become taller, the troughs deeper. You might say that compressed waves become more "ample." Physicists define amplitude as the maximum rise of the wave's crest from the horizontal surface, from the midpoint between peak and trough. The intensity of light is proportional to the amplitude, or the crest height.

According to Einstein, mass-energy has reached the maximum attainable velocity when it assumes the form of light. Conversely, when mass-energy hasn't reached that maximum speed, it isn't light. Energy is more concentrated in blue light than in, say, red light. Since the mass-energy can't move any faster or slower, and since something must accommodate the difference, blue light waves compress closer together than red ones; and, compared to red waves, blue waves exhibit greater amplitude and frequencies, and shorter wavelengths.

But not all waves move at the speed of light. Water waves certainly don't, nor do sound waves. Unlike light, the amplitude and frequency of these waves are independent of each other. This is why for example, a high-pitched squeak may be of very low amplitude, and a deep, rumbling, low-frequency bass sound may be intense enough to knock you out of your seat.

But one thing is true about any wave: put amplitude together with phase and you completely define the wave. As mathematical physicist Edgar Kraut has written, "A complete knowledge of the amplitude and phase spectra of a function [the mathematical essentials of an equation] determines the function completely."[2] Kraut uses the term spectra because phase and amplitude define not only simple waves but complex ones as well. We'll see later in the book that complex waves are made up of simple, regular waves.

What is wave phase? The formal definition of the term describes it as that part of a cycle a wave has passed through at any given instant. Engineers and physicists use the term cycle almost interchangeably with wavelet . This is because the points on a simple, regular wavelet relate directly to the circumference of a circle, or a cycle. For example, if what is known as a sine wavelet has reached its amplitude, it has passed the equivalence of ninety degrees on the circle.

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Phase also implies knowledge of the wave's point of origin, as well as every point through which the wave has passed up to the moment of observation. And the future course of a simple regular wave can be predicted when we know what phase it is in, just as we can predict how much of a circle remains the instant we reach, say, 180 degrees. Amplitude represents the bulk mass of a wave, whereas phase defines just where or when that mass will be doing what, in space or time. Phase instantly manifests to the observer the way a wave has changed since its origin, and how it will continue to change, unless outside forces intervene.