SOHO, the Solar & Heliospheric Observatory orbiting the sun, observed a wide coronal hole on September 19, 2007. It appears as the large dark area in this image, which records the wavelength (284 Angstrom) of extreme ultraviolet light.

The coronal hole has been rotating around towards the center of the Sun for about a week. Since such holes are 'open' magnetically, strong solar wind gusts can escape from them and carry solar particles to our magnetosphere and beyond. Solar wind streams take several days to travel from the sun to Earth, and the coronal holes in which they originate are more likely to affect Earth after they have rotated more than halfway around the visible hemisphere of the sun, which is almost the case here.

The magnetic field lines in a coronal hole open out into the solar wind rather than connecting to a nearby part of the Sun's surface. High-speed solar winds can directly affect the "space weather" near the earth. People living at higher latitudes may see some especially colorful auroral displays in the next few days.

SOHO (ESA & NASA) and SPACE.com Staff

Credit:SOHO (ESA & NASA)