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None of the Russians' three massive Sputniks had reported the Van Allen radiation. One theory is that the Russians outsmarted themselves by refusing to tell the outside world how to interpret signals from their satellites. Since only the low parts of the Sputnik orbits were over Soviet territory, Russian scientists never got reports from high altitudes. If any of the Sputniks carried tape recorders, they apparently did not work.
Another theory is that the Sputniks' Geiger tubes were blacked out near apogee by Van Allen radiation, and that the Russian scientists did not know how to interpret this odd behavior. The live dog carried in Sputnik II died in about a week, but the Russians have not told whether it was affected by radiation sickness. Very likely they do not know.
The Slot. Van Allen still knew only the lower parts of the overhead radiation. He yearned to go higher still. He began negotiating to get his instruments into the projected moon probes. When in the fall of 1958 Pioneer I rose to 71,000 miles and fell back, Van Allen had his instruments aboard. But for once, they did not work well. Pioneer II flopped, but in December Pioneer III carried his instruments up to 63,000 miles, broadcasting all the way.
From Pioneer III, Van Allen discovered that there are not one but two radiation belts, with a low-intensity slot between them. Studying the tapes, he concluded that the outer belt is made of weaker particles, presumably protons and electrons that come from the sun. At its outer edges, it curves downward in "horns" that hit the atmosphere near the magnetic poles. These horns were what produced the northern lights.
Van Allen's conclusions were confirmed when Pioneer IV soared past the moon and into orbit around the sun. Its tiny, 1-lb. radio transmitter, which was followed by Jet Propulsion Laboratory's receiving stations for 400,000 miles, reported that the outer radiation belt does not die off evenly. Beyond it are irregular bursts of radiation that may be clouds of electrons and protons arriving fresh from the sun. Such invisible clouds in space may prove serious hazards for future deep-space voyagers.
Van Allen summed up his conclusions: "Apparently, something happens on the sun. It sends out a burst of gases. The reservoirs above our earth shake like a bowl of jelly. The radiation droozles out at the ends and makes the auroral displays at the North and South Poles."
Hole in Space. Widely popular in a profession full of jealousies, Van Allen has a cheerful scorn for his new-found importance. Recently, he told a solemn gathering of scientists, he had been asked for a definition of space. "After a vast research program, which depended very heavily upon the use of a number of highspeed computers, I am pleased to offer you the result: 'Space is that in which everything else is.' In other words, 'Space is the hole that we are in.' "