SOLVING OF SUN’S RIDDLES — Future space probes may skim as “close” as two million miles from the sun’s visible surface, a report to the National Academy of Sciences suggests. Before this can be done, however, greatly improved materials must be developed since temperatures at that distance would be about 5,000 degrees Fahrenheit, roughly the melting point of the toughest materials now known. A near-sun space probe is one of the several kinds of solar studies from high-flying balloons, satellites and probes recommended by the Academy’s Space Science Board. The suggested experiment could yield answers to most of the still unsolved problems of the sun and its mighty outpouring of radiation.
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