National Geographic : 1953 Jan
Trailing Cosmic Rays in Canada's North 20 Miles Aloft over Hudson Bay, Scientists Find Clues to Origin of High-speed Atomic Particles That Bombard Earth BY MARTIN A. POMERANTZ Leader, National Geographic Society-Bartol Research Foundation Cosmic Ray Expeditions TAND by to release!" Our six bal loons, fastened together in tandem, were bobbing and straining at their ropes as we struggled to hold them against the chilling wind of the early subarctic dawn. Bob Pfeiffer, one of my associates, held high the 15-pound gondola containing four Geiger counters which the balloons would carry into the stratosphere. "Let her go!" Balloon Train Takes Off At the word, the balloons soared upward but also were carried along horizontally by the wind. Bob had to run with the precious gondola to make sure it did not drag on the ground before it was lifted clear. Weary as I was, I felt a thrill of excitement. At last we were embarked upon our far-north ern venture, on the trail of new facts about those mysterious messengers from outer space, the invisible but vastly powerful cosmic rays. These rays are really atomic particles that constantly pelt down upon the earth from all directions at terrific speed. So great is their energy that they shoot right through the bodies of all human beings an average of 10 times a second and penetrate everything else on our planet as well. Some even plunge far down into the earth, to the bottoms of deep mines and beyond. This unceasing bombardment has no known effect, either good or bad. But the energy of only one cosmic ray of the most powerful type is a billion times that released from a single uranium atom in the explosion of an atomic bomb. Because they possess this enormous energy, cosmic rays are teaching us things about the atom that we could learn in no other way. Some atomic particles were first discovered when they were blasted out of atoms by cosmic rays. From this natural atom smashing we are learning much about the powerful nuclear forces that hold atoms together. Here in the north we were hoping to find at least part of the answer to one great cosmic ray question: Where do these mysterious par ticles come from? It was certain that their origin was far away from our planet, but just where was still unknown. Though we did not know it then, luck was to be with us on our quest for the answer. Under co-sponsorship of the National Geo graphic Society and the Bartol Research Foundation, we were to spend parts of two summers studying cosmic rays here on the bleak and lonely shores of Hudson Bay, at Churchill, Manitoba, once called "the town 500 miles from nowhere" (map, page 103). Around us, to the north, west, and south, stretched the flat, swampy, lake-dotted mus keg, with Churchill's low wooden buildings almost lost in its vastness. To the east rolled the wind-whipped waters of Hudson Bay, barely above freezing temperature even on this August day, as we later quickly learned from an ill-advised venture at taking a swim! Messages from the Sky We watched our balloon train gradually dis appear into the lonely, empty, subarctic sky. Then I went inside our crowded trailer labora tory, donned earphones, and listened intently for the automatically transmitted radio signals that should be returning to us from the Geiger counters as they were carried aloft. Sure enough, the sounds were coming, strong and clear, an unevenly spaced "z-s -t, z-s -t, z-s-t," with a metallic overtone, like the spark of an old-fashioned telegraph key. Those buzzing noises from out of the sky may not sound like the grand music of the spheres of which poets have sung, but they were true music to the ears of my associates and myself, for they were what we had journeyed 2,600 miles to the north to hear. Each buzz was the "music," if you will, of a cosmic ray which had traveled, perhaps for thousands or even millions of years, from far off in the universe and was now impinging upon our balloon-borne Geiger counters. As each ray struck the counters, a radio signal would flash back down to earth to be picked up by our receiver and cause a mark to be made on moving paper tape. We used some 50 miles of tape to record our data. Rising rapidly into the stratosphere, our train of balloons soon would carry the count ers to an altitude of more than 20 miles, where 99 percent of the earth's air blanket lay below. Up there, practically at the "top of the at mosphere," in the cold silence where the air is highly rarefied, we wanted to obtain a count of the numbers of cosmic rays plunging to ward us from outer space.