Important notice about the deactivation of the STEREO ftp
Important notice about STEREO Behind
First Sunspot of New Solar Cycle
Which magnetic polarity leads and which follows in solar active regions alternates with each, roughly 11.1 year solar activity cycle (and is opposite in the Sun's northern and southern hemispheres). Thus, the first active region with opposite ordering of polarities is recognized as the harbinger of a new solar cycle. Cycle 24 began when it was officially confirmed on January 4, 2008, that SOHO had observed the first "reversed" sunspot of the new solar cycle, something scientists have been seeking for about a year. On that day, the fairly petite active region was named a sunspot by NOAA. Since it appeared at a high solar latitude and its magnetic orientation is opposite of the last solar cycle, scientists were convinced that Solar Cycle 24 has begun.
But not only did it appear, it generated two EIT waves, a kind of solar storm that blasts out from an active region across a portion of the Sun's surface. The larger of the two waves is shown in this video clip (January 7, 2008, covering about six hours) in extreme UV light from the STEREO Ahead spacecraft. So the cycle started out with a bit of a bang to it. However, this is just the beginning as solar activity will increase slowly over the next few years until it reaches another maximum predicted to occur in 2011 or 2012.
Last Revised: March 19, 2018 15:00:39 UTC
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