Living With the Atom

New Zealand Listener, Volume 36, Issue 925, 3 May 1957, Page 5

Living With the Atom

WE are naturally more curious about what lies over the horizon and beyond the farthest stars than in the earth beneath our feet, but even below us there is still much to arouse our interest. What, for instance, lies at the centre of the earth? Is it an inner hard core as many geologists believe, or is it a molten mass? Unexpected help in deciding the question has appeared in the form of atomic explosions. We are so used to hearing of the harmful effects of the atomic bomb that it is something of a surprise to find anything useful coming from its explosion. Yet nuclear explosions are at present being

used by scientists to find out more about the deep interior of the earth. Formerly this kind of knowledge was gained as the result of earthquakes. The waves sent down by an atomic explosion, however, are the same kind as -earthquake waves, and can be recorded on a seismograph. Although — the energy released in a "natural" earthquake is far greater than that released in the largest atomic explosion’ the atomic explosion is extremely useful to the scientist because it can

be controlled. A scientist who has done considerable research on this topic recently visited New Zealand for the Science Congress at Dunedin. He was Professor K. W. Bullen, Professor of Applied Mathematics at the University of Sydney. In a talk-Atom Bombs and Earthquakes-for the interested layman he describes his work. He is mostly concerned with the results of the four hycrogen bomb explosions set off in the United States during 1954, and he shows how these have helped increase our knowledge of the mysterious centre of the earth. (2YA, 7.15 p.m. Thursday, May 9; 4YA, 7.15 p.m., Monday,

May 6; and trom 1YA and 3YA during the week beginning May 27.) Another alarming aspect of atomic explosions is that of radiation. Raciation has presented dangers to human beings ever since hospitals and dentists began using X-rays, but in the last few years radiation from many different sources has increased considerably. The greatest source is still the radioactive fall-out after an atomic explosion. In a talk called Atomic Radiation and Ourselves a young New Zealander from Dunedin, W. K. Sinclair, who is now Professor of Physics at the University of Texas, and in charge of the M. D. Anderson Tumour Research Institute, tells of the main sources of atomic radiation today, and shows how scientists are finding ways of protecting human beings from excessive radiation and possible future genetic damage. We may not know it but every day each one of us is exposed to small amounts of natural radiation from many different sources, It comes from cosmic radiation from outer space; from ‘tiny amounts of radioactivity in the walls of buildings, streets, drinking water; from the air we breathe. and even from within the body itself. But because the level of radiation of these sources is very low, unlike that from an explosion, they do no harm at all. (2YA and 4Y A, week beginning May 13; 1YA and 3YA, week beginning June 3.)