A GASH IN THE SUN'S ATMOSPHERE
Magnetic maps of the sun's atmosphere reveal a long gash, more than 700,000 km long, where solar wind may be spraying into the solar system. This image of the structure is based on data from NASA's Solar Dynamics Observatory
Astronomers call this a "coronal hole"--a region when the sun's magnetic field opens up and allows solar wind to escape. Coronal holes are common, appearing every few weeks. This one, however, is uncommonly long and narrow. A fan-shaped spray of gaseous material flowing from the gash could reach our planet as early as Dec. 23rd. Arctic sky watchers should be alert for auroras when the solar wind arrives.