Recent advances in techniques and equipment for x-ray observation of astronomical objects have resulted in the accumulation of enough information to enable checking the general nature of the observational results against the theoretical picture derived from development of the consequences of the postulates of the Reciprocal System of physical theory, the RS theory, we will call it for convenience. X-rays can, of course, be produced in relatively small quantities by a number of different processes, but the RS theoretical development indicates that the source of the very strong radiation in this frequency range that is generated in astronomical objects is radioactivity from matter which has reverted to speeds below unity (the speed of light) after having remained at a higher speed long enough to attain isotopic stability at the ultra-high speed.

From the very beginning of the kind of disciplined thinking about the physical world that we now call science, one of the major objectives has been to identify its basic constituent, or constituents; to answer the question, What is the world made of? The earliest theories of which we have detailed knowledge, those developed by the Ionians in the years from about 600 to about 400 B.C., and by the Chinese around the same time, were of two general types. One group of philosophers, reasoning from an assumption as to the unity of nature, argued for a single constituent. Water was the usual choice, although there was some support for air. Another group contended that the great multiplicity of physical forms required the existence of a number of basic constituents. The most popular choice among the early investigators in the West was a four-element universe, constructed of earth, water, air, and fire, an identification that achieved a kind of an official status when it was accepted by Aristotle. The Chinese recognized five basic elements, omitting air and adding metal and wood.