Madeline Chambers, age 13, of Canton, Ohio, for her question:
What are solar flares?
Our sun, as we know, is a nuclear furnace with a tremendous output of energy. The latest information suggests that its energy increases to a maximum peak and then subsides. This period tallies with the 11 year sunspot cyc1e. Solar flares occur when sunspot activity is at its peak, and at this time the sun is estimated to be 2% brighter than normal.
The International geophysical Year was set to start on July 1, 1957. Astronomers and geophysicists round the world were ready to study the sun during a peak period of sunspot activity, and they were not disappointed. Solar flares¬ were expected, and these dramatic events were given special attention, since they upset our radio and telegraph communications.
A world wide ring of stations was set up as a flare patrol. Since a solar f1are lasts from only one to 10 minutes, the face of the sun was photographed every 30 seconds. A series of radio stations was tuned to catch the signals which rush out from a flare at the speed of light.
Three days before the IGY began, a station near Moscow reported a huge solar f1are. When our side of earth turned to face the sun, the scientists saw what they expected. The f1are itself had subsided, but the Suns face was marred with an outstanding rash of sunspots. At 4 a.m.., June 30, world wide radio and telegraph was disrupted, and an hour later North America was spanned by bands of dazzling auroras from the Great Lakes to Texas.
With this solar eruption, the IGY was off to a blazing start. Rashes of sunspots followed one upon another, and marry solar flares erupted near them. Rockets ignited on the alert like fire engines and went aloft for data during and after many of the solar flares. Short wave X rays strike our upper atmosphere within minutes of a major flare, and experts suspect that this hard radiation causes the disruptions and blackouts in our communications.
A solar flare is some what like a nuclear explosion on the face of the sun. It may flare up 50,000 Miles at 500 Miles a second and engulf perhaps a billion cubic miles in seething radioactivity. A stream of its energy hits our atmosphere in eight minutes. It disrupts radio on the sunlit side of the earth. A slower stream of flare activity may or may not strike us 12 to 36 hours later. It can disrupt communications on a World wide Scale and reward us with an extra special display of shimmering auroras.
We know that solar flares occur near rashes of sunspots and that sunspots build up to a peak and diminish during an 11 year cycle. But so far science cannot explain what causes this cycle of solar activity. Certain variable stars shine brighter at regular intervals, but We cannot explain why. Some experts suggest that our sun is a variable star. In each 11 year Cycle it blazes up to a peak of sunspots and solar flares and then subsides.