| Popis: |
“Cosmic rays” is the name of the ultimate cause which maintains that part of the ionization of the air which cannot be ascribed to the rays of radio active substances on earth nor to any other known agency. The measurement of this residue, the discrimination between it and that part of the ionization which is due to familiar rays, is the first problem of cosmic-ray research. Second comes the problem of learning, from measurements made at as many places and under as many conditions as possible, the nature of the mysterious ionizing agent. One naturally begins by assuming it to be like in kind to one or another of the known types of ionizing rays, but different in quality; e.g. to consist of electrons faster than any known electrons, or photons of greater energy and lesser wave-length than any known photons. It is not yet certain whether one of these hypotheses will fit, or rays of some new type must be imagined. The direct measurements of ionization are supplemented by observations of material particles of evidently enormous energy which dart across the atmosphere in straight paths leaving trains of ions behind. On the whole it seems highly probable that these particles, or those (if such there be) from which they receive their energy, come to the earth from outer space; and the energy which they bear is so great, that its source must be some process not yet known. |
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