A MILLENNIUM BALL

The two STEREO space-based observatories launched in 2006 capture ultraviolet wavelengths. Here, the sun, looking like an LED-encrusted crystal ball waiting for midnight in Times Square, shows a dark coronal hole visible in the lower right quadrant. STEREO observes solar storms and probes coronal mass ejections, which can disrupt satellites, endanger spacewalking astronauts, and even knock out earthly electric power.