Centuries-old sketches solve sunspot mystery

 作者:蔺晏     |      日期:2019-03-14 02:20:02
By David Shiga A SECOND look at sunspot drawings from the 1700s has clarified a puzzling episode in the sun’s history, and could lead to more accurate forecasts of dangerous solar outbursts. The sun sometimes hurls clouds of plasma our way, which can fry satellites and knock out power grids on Earth. The outbursts are most common during solar maxima, when the dark blemishes of sunspots appear in greatest abundance on the sun. Although there is an average of 11 years between solar maxima,