Modern Physics

MODERN PHYSICS So long as we are dealing with massive bodies or with great groups of particles, the laws of dynamics, based upon Newton's laws of motion and applied without any breach of continuity, were sufficient and reigned supreme. This kind of dynamics domi nated the 19th century, but just at the end, as a fitting prelude to the loth century, a number of discontinuities began to be dis covered. The first discontinuity was indeed old, viz., the atomic theory of matter, and was only evaded by the fact that we inev itably dealt with great numbers of atoms. In the years 1897 to 190o however Sir J. J. Thomson, elaborating some 1879 experi ments of Sir William Crookes in a partial vacuum, discovered and finally clinched the discontinuity of electricity; in other words he realized the electron, which had previously been only surmised rather vaguely by a few. Zeeman and Lorentz had just showed that electric charges were the agents really responsible for the generation of radiation, a fact further illustrated and enforced by ROntgen's discovery of X-rays. After their isolation electrons were weighed and measured by Thomson, and found to possess the fundamental properties of matter. The nature of radiation as emitted by electrons was analysed and examined in precise detail by the spectroscope. Then another discontinuity was discovered by Max Planck, for, as soon as single atoms and their constituent particles were attended to, a new discontinuity appeared, appar ently in radiation, but rather in what turned out to be a quantity connected with the orbital revolutions of an electron, akin to the sweeping out of equal areas which Kepler long ago had formu lated for the planets; and Bohr formulated his astronomical the ory of the structure of the atom. So through various channels it was found that these fundamental electric units, which were presumably structures in the ether, lay at the root of matter itself, and that matter was actually an electrical phenomenon. Discon tinuities are natural and inevitable when dealing with individual minute particles; they were only masked in previous days because this minute treatment had not been attempted, though a hint had been given in that direction by the failure of the kinetic theory of gases, as ordinarily applied, to explain the irregular movements of very small bodies exposed to molecular bombardment.

The Theory of Relativity.

Then came the theory of rela tivity, which adopted, generalized, and boldly formulated a num ber of vague but growing suspicions. In particular it postulated a universal and unalterable constitutional velocity in the ether now known as c, which had been recognized in Clerk Maxwell's theory as of an electromagnetic nature, but the nature of which is still unknown. This, like Planck's constant h, is found to enter into every department of physics, not only conspicuously when minute bodies are dealt with, but secretively throughout. All matter is moving through the ether, so that the constitutional velocity c of that medium enters into and modifies even the Newtonian laws of motion, thus giving a complexity which sometimes seems strange to ordinary or evolutionary experience, and with a little ingenuity can be made to appear paradoxical. Many other results of high interest follow, and the gravitational function of the medium shows signs of yielding to mathematical treatment.

The revolutionary outcome of all this is that the ether in its various forms of energy dominates modern physics, though many prefer to avoid the term "ether" because of its 19th century asso ciations, and use the term "space." The term used does not much matter. Faraday began the discovery that it is in space that the real phenomena occur. Every differential equation is an expression in space with its three dimensions and the other ab straction called time; and some attempt has been made to unify these two great abstractions by aid of the velocity c. This how ever is rather verging on metaphysics, unless it is merely regarded as a legitimate convenience in calculation to deal with four similar variables instead of three and an odd one.