THE COSMIC RAYS

Taranaki Daily News, 16 April 1932, Page 13 (Supplement)

THE COSMIC RAYS

PROF. COMPTON’S QUEST

(By

Rev. B. Dudley,

F.'R.A.S.)

In view of the imminent visit to New Zealand of Professor Arthur H. Compton, the American scientist, in order to head an expedition to Mount Cook for the purpose of making certain tests in connection with the recent discovery of cosmic rays constantly being poured into the earth’s atmosphere, the following may be found of interest to readers of this column.

The professor is a distinguished authority in physics. His party hope ultimately to find out whether the rays in question come from the stars (the Sun included as one of these) or from socalled empty space. Numerous experiments have shown that they are certainly and ceaselessly arriving from all directions in outer space, and that they are extremely penetrating. Dr. Millikan, the noted physicist, was among the first to determine their absorbability. 'This he did by lowering his instruments deep in some of the lakes among the Rocky Mountains in North America. It was thereby shown that these rays are absorbed in their passage through matter, and to what extent the absorption takes place. In penetration power, they are known to be far greater than the gamma rays which, will pass through a thick block of lead. Their absorbability being known, the wave-length of the radiation is easily ascertainable, as the two things, in accordance with a well-known formula, are connected. The absorbability is measurable by noting the degree in which the rays fall off on passing through known thicknesses of matter. It is expected that from a knowledge of their wave-length much information will be gleaned as to the origin of the waves. Sir James Jeans thinks that matter located at the centre of our Sun and of all the stars is constantly being annihilated through the fusion of protons and' electrons, resulting in their conversion into radiant energy. “The rays,” says Sir James, “come to us as messengers, not only from the farthest depths of space, but also from the re? motest reaches of time,” and he suggests that since it is not in our power to produce cosmic rays on earth, their ; message to us is that the physics which prevail in the far depths of space and time are something different from our terrestrial physics, different processes resulting in different products. That is to say, Nature is not necessarily the same everywhere in her operations; the laws and properties of matter in relation to mechanics, dynamics, light, heat, electricity, etc., varying in ways little dreamed of by us, who are apt to judge of all things ‘by what we see or know to obtain on earth. If the cosmic rays do not come from the stars, where pressures, densities and temperatures are enormously high and likely to give rise to the radiation, there is an alternative to be considered. They might come from inter-stellar space, usually thought of as being devoid of matter, where the temperatures, densities, and pressures are extraordinarily low. Professor Millikan takes the view that these creative processes which cause the rays do not operate within the stars. The Sun is the star near us; but the cosmic rays, it has been discovered, do not enter our atmosphere more by day than by night, as they surely would do if the Sun. had anything to do with their origination. His own words are, “We may not only conclude quite definitely that the stars are not the sources of the cosmic rays, 'but also that the main atom-building processes probably do not take place inside of stars at all.” Eddington and Jeans find the source ,of stellar heat not in any atom-building process whatsoever; but rather in an atom-annihilating process going on in the interior of stars, where positive electrons are continually transforming their entire mass'into ether waves. The atom-building as against the atomdestroying process occurs, as their experiments seem to show, outside the stars. Dr. C. Coleridge Farr, professor of ' physics at Canterbury College, Christchurch, puts the case as between Jeans, and Millikan thus; “Whether these rays originate—as they may, and as is believed by Jeans to be the case in an absolute destruction of matter, or whether—as Millikan asserts they originate in the formation of more complex elements from the simplest constituents, is the question which modern scientists have to decide. In other words, is the universe self re-establish-ing or self-destroying?” The question, he adds, can be settled only by an exact knowledge of the absorbability of the rays themselves; for, knowing this, we 'have the means of learning their wavelength, which is the object of Professor Compton’s quest. According to Professor Millikan, the rays arc produced 'by the union of electrons to form atoms of ordinary matter; and that is why he calls them “messengers of creation.” If his theory is correct, then space, instead of being “an empty box with the top, the sides and the bottom knocked out,” is the seat of quite the most important processes going on in the whole extent of the universe. The professor states that “it may be regarded as established by the evidence heretofore advanced that the cosmic rays are the signals sent out through the heavens of the creation of the common elements out of positive and negative electrons.” Rutherford was early in the field in respect to the actual discovery of cosmic radiations. Regencr followed on, extending the 'absorption experiments by letting down his instruments to successive depths in Dake Constance. Eddington and Jeans see in the evidence available a universe running down to a finish, while Millikan takes from the experiments hitherto conducted the view that, while the sun and the stars are continually destroying atoms in their interiors and throwing them off in the form of radiant energy, new atoms are being as continuously formed out of the hydrogen throughout space and rained down upon ail stellar 'bodies in the form of the cosmic rays in which these British and American experts are interested. Profess Compton by his experiments here and in Australia may or may not assist us in coming to some such conclusion as he, in common with Millikan, has reached; viz., that in these mysterious radiations we see operating a force which constantly maintains the universe, a force they (also in common) speak of as “Creator.” Fantastic as the ideas involved in this line of study would have seemed a few generations ago, it is now impossible to dismiss them as not worthy of the earnest consideration of the foremost scientific men; and, as was recently remarked by a competent authority, we may be thankful that in these matters we have both pioneers and critics of the very highest quality.