Sun's Massive Hole Sends Solar Winds to Earth.

A giant coronal hole on the sun, about 20-30 Earths across, has been spotted by NASA's Solar Dynamics Observatory. Coronal holes are cooler in temperature and appear black against the rest of the sun. These holes are common and are the source of rapid solar winds that travel at 500-800 km per second. The relatively-harmless winds are expected to reach Earth by March 24, causing a more vibrant aurora borealis. As solar activity increases, coronal mass ejections and solar flares will become more common, which can cause power grid surges and satellite damage.