Word: sunspots
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Pilgrim would be launched during a period of major sunspot activity, and Huguenin hopes to find new facts about the atmosphere of the sun and about sunspot emission...
...solar patrol will have to take care not to set off a false alarm that might unnecessarily abort a costly Apollo mission. But on the basis of past observations, the patrolmen know that if a flare is large and bright enough, if it is located close enough to a sunspot and is the source of strong radio signals over a wide range of frequencies, its appearance almost always heralds a hail of high-energy protons...
...Noise Storm. A noise storm consists of a series of short individual bursts of radiation, each lasting a minute or less. The source of these bursts is a turbulent area in the corona above an active sunspot. An entire noise storm may last for hours of days. The bursts are generally confined to a narrow range of frequencies, not greater than 30 megacycles, because the emitting region is at a fairly constant height in the corona...
While physicists are debating the cause of the flares, practical solar meteorologists are learning to identify solar weather conditions that may produce them. First, says Dr. James Van Allen, discoverer of the Van Allen radiation belt, a sunspot must be visible. A group of several sunspots is even more likely to produce a flare, but not all do. Often they fade away without a blowoff...
Best hope for unshielded space travelers : the flares may die away during the low points of the eleven-year sunspot cycles, the first of which should come in about five years...