Associated Press: The sun has been unusually quiet lately, with fewer sunspots and weaker magnetic fields than in nearly a century. A quiet sun is good for Earth: GPS systems are more accurate, satellites stay in orbit longer; even the effects of manmade global warming are marginally reduced, though just by three-tenths of a degree at most. It’s all a normal part of the strange but regular cycles of the sun’s activity. Scientists don’t know why it happens, but “for humankind it’s probably a good …