Spring on the Sun

In January, solar scientists found their first robin of the sun’s spring. It was a sun spot, a little black dot on the visible surface of the sun. This spot was somehow different from the spots that had come before and from spots still on the sun. This spot had a different magnetic polarity, and was in a different place than previous spots. The news was clear: the long awaited first sign of Solar Cycle 24 had arrived. The sun’s winter, known as “solar minimum,” was midway through and the new solar cycle had begun.

The analogy of spring can only be taken so far. The sun does go through activity level changes, just like we do in different seasons, and these changes are related to the sun’s average temperature. But the sun doesn’t have seasons, just an ongoing 11 year cycle of magnetic storm activity. It turns out that the sun’s average temperature is lower during the multi-year lull in sunspot activity, and is greatest during the peak, called solar maximum.

Like a human going through puberty, the sun face is always changing, and its most noticeable feature is the scattering of spots on its face. The spots indicate areas where the turbulent and twisted magnetic field lines are organized and the normally bright plasma of the sun is slightly cooled and darkened. They appear darker against the bright background of hotter plasma, and that is what we see as a sunspot. Sunspots form often form in pairs or groups. They have a system of polarity, just like magnets have south and north poles. They form in somewhat predictable ways throughout an entire solar cycle. One of the clues scientists have been looking for is the switch in polarity of spots that form in in either the northern or southern hemisphere of the sun. This is one of the clues that indicate the official end of cycle 23 and the beginning of the new solar cycle.

Another clue is where the spots form on the sun. New solar cycles always begin with a high-latitude, reversed polarity sunspot. Old cycle spots form near the sun's equator. New cycle spots appear higher on the sun, around 30 degrees above the sun’s equator. The new spot was high and backward, indicating cycle 24 had begun. Now the sun’s activity would grow day by day over the course of the next 4-6 years.

Though we’ve turned the corner in the sun’s growing activity, it takes years to peak. Scientists predict that the upcoming solar cycle will be quite fierce when it peaks around 2011. What that means is that we will be vulnerable to the effects of solar storms, like power grid overloads causing power outages, cell phone and other communication interruptions due to satellite malfunction, GPS malfunctioning and air traffic problems. One pretty side effect caused by excess solar particles in our atmosphere is the Northern Lights. Scientists predict this solar cycle will be famous for Northern Light displays. We‘ll have to wait for solar max to see these spectacular Auroral displays, however. Meanwhile we can enjoy the heightening daily path of the sun, and that it lingers longer as the days go by. Spring is indeed coming.

Until next week, my friends, enjoy the view.