The new solar cycle starts with a bang
A sunspot, discovered by SOHO, indicates the beginning of a new solar cycle.
Provided by ESA, Noordwijk, Netherlands
January 17, 2008
A very special solar spot on the Sun's surface appeared a few days ago. This solar spot, which produced two blasts, signaled to scientists around the world that a new solar cycle had begun.
Each solar cycle lasts an average of 11.1 years. The new solar cycle, called Cycle 24, started on January 4, when the Solar and Heliospheric Observatory (SOHO) observed an event scientists have been anticipating for about a year.
A fairly small and, at first sight, inconspicuous sunspot on the Sun's northern hemisphere showed a reversed magnetic polarity compared to sunspots of previous years. A sunspot is an area of highly organized magnetic activity on the surface of the Sun. This sunspot convinced scientists that a new solar cycle had begun. Later that day, this finding was made official when the sunspot was catalogued by the US National Oceanic and Atmospheric Administration (NOAA).
SOHO also observed two associated "EIT waves," blast waves that spread out from active regions on the Sun like ripples from a pebble dropped into water. This is just the beginning, and scientists are now eagerly awaiting the activity to follow. Solar Cycle 24 is expected to build gradually, with the number of sunspots and solar storms reaching a maximum by 2011 or 2012, although intense solar activity can occur at any time.