World of Change: Solar Activity

The Sun’s activity waxes and wanes as magnetic field lines that are inside the Sun periodically break through to the surface. These breakthroughs produce a pair of sunspots of opposite magnetic polarity that travel together across the face of the Sun. The heightened magnetic activity associated with sunspots can lead to solar flares, coronal mass ejections.

This series of images shows ultraviolet light (left) and sunspots (right) each spring from 1999-2010. Sunspots darken the visible surface of the Sun, producing intensely bright areas. The most recent forecast from the Space Weather Prediction Center is that solar cycle 24, which began in 2008, will be of below-average intensity, and will peak in May 2013. The small changes in solar irradiance that occur during the solar cycle exert a small influence on Earth’s climate.

Images acquired from the Solar and Heliospheric Observatory (SOHO) spacecraft

Reference: NASA’s Earth Observatory

See http://earthobservatory.nasa.gov/Features/WorldOfChange/solar.php