Heads up, night owls and sky gawkers: Mother Nature is putting on a show. The northern lights are expected to dance across 16 states tonight, thanks to another burst of solar fireworks. A “fairly fast coronal mass ejection” spotted over the weekend prompted the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center to issue a geomagnetic storm watch this week. Once that solar surge slams into Earth, the northern lights could spill farther south than usual — treating