THE SUNSPOT FORECAST

摘要

Although sunspots are making a belated comeback after the protracted solar minimum, the signs are that all is not well. For decades, William Livingston at the National Solar Observatory in Tucson, Arizona, has been measuring the strength of the magnetic fields which puncture the sun's surface and cause the spots to develop. Last year, he and colleague Matt Penn pointed out that the average strength of sunspot magnetic fields has been sliding dramatically since 1995.