LONG RANGE OUTLOOK: A stream of solar wind is heading for Earth, due to arrive on July 28-30. High-latitude sky watchers should be alert for auroras on those dates in case the impact sparks geomagnetic storms. Aurora alerts: text, voice.

MAGNETIC BRIDGE: Sunspots AR1528 and AR1529 appear to be far apart. More than 200,000 km of stellar surface separate the two. Nevertheless, they are connected by a tubular bridge of magnetism. NASA's Solar Dynamics Observatory (SDO) photographed the vast structure on July 24th:

This extreme ultraviolet image traces the bridge via the glow of hot plasma it contains. Material can flow back and forth inside the tube, allowing one sunspot to respond to what the other is doing.