Word: solarity
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Dates: during 1980-1989
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Aristotle's view prevailed through the Middle Ages, was embraced by Christianity and went largely unquestioned until Galileo and other early 17th century sky watchers pointed the newly invented telescope at the sun and saw black spots on its surface. So much for solar purity. Despite clerical disapproval, the reality of sunspots was quickly accepted. Still, more than two centuries passed before Samuel Heinrich Schwabe, a German apothecary and amateur astronomer, discovered the strange, cyclic behavior of the solar blemishes...
Schwabe had been searching for the hypothetical planet Vulcan, supposedly the closest one to the sun, hoping to spot it in silhouette as it moved across the solar disk. In the process, he observed and kept meticulous records of sunspots over a 17-year period. Finally, in 1843, he recognized and announced the eleven-year cyclic nature of the spots and wrote, "I may compare myself to Saul, who went to seek his father's ass and found a Kingdom...
...back to the early 18th century and using improved telescopes, satellites, advanced instruments and modern theory, scientists have become ever more familiar with the bizarre dance of the sunspots. Each cycle begins when spots show up in both the northern and southern hemispheres about 35 degrees away from the solar equator. As the cycle matures and the older sunspots fade away (some last only a few hours, others for weeks and even months), new and more numerous spots appear at lower latitudes. Toward the end of the cycle, diminished in number, they appear at latitudes some 5 degrees from...
Sunspots tend to travel in pairs or groups of opposite polarity, like the ends of horseshoe magnets poking through the solar surface. During one eleven- year cycle, as the blemishes traverse the face of the sun in an east-west direction, the leading spots of each group in the northern hemisphere will generally have positive polarity, the trailing spots negative. In the southern hemisphere, the leading spots will be negative. During the next cycle, the hemisphere polarities will reverse. On average, then, 22 years will pass between solar maximums of the same sunspot polarity. This suggests to many astronomers that...
Since the sun in myriad ways governs the very existence of all terrestrial life, the cyclic changes in the sunspot population have, ever since Schwabe, inspired speculation about their effect on solar radiation and, consequently, on the earth. Though the sun is a rather ordinary star, its vital statistics are breathtaking by earthly standards. Some 865,000 miles in diameter, it consists largely of hydrogen (72%) and helium (27%) and is 333,000 times as massive as the earth. Solar temperatures range from about 27 million degrees F* in the core, where 600 million tons of hydrogen are fused into...