…and it’s about time!  Seemed like we were heading into another Maunder Minimum there for a while.  Okay, maybe I’m exaggerating a little, but we did go through a long stretch of time when we should have been seeing sunspots and we were not.

So what?  It’s not like sunspots do anything, right?

National Science Foundation, Dunn Solar Telescope, NSO, AR 10810

Wrong.  There’s actually a lot going on with them.

Sunspots are in fact areas of intense magnetic activity.  The increased activity inhibits convection, causing cooler areas to form on the surface.  “Cooler” is, of course, relative.  A sunspot is about 3,500 K; while the Sun’s average surface temperature is about 5,800 K.  Sunspots only appear dark against the brilliant glare of the Sun.  If you could hold a sunspot away from the surface you would see that it’s brighter than an electric arc.

NASA/TRACE 09/2000 Sunspot in UV

The frequency of sunspots follows an approximate 11-year cycle.  The time period which has the most sunspots is the Solar Maximum, the least is the Solar Minimum.  Variations in the cycle appear to coincide with climate variations on Earth.  The Maunder Minimum (ca 1645-1715) was during a period of overall cooler temperatures known as The Little Ice Age.  How or if sunspot activity and climate are linked is unknown, as is unknown which is the cause and which is the effect.

Records of solar cycles have been kept since March 1755 (cycle 1).  We are currently in cycle 24, which began January 4, 2008.  Sunspots don’t just pop up at random all over the Sun, but are concentrated in two latitude bands on either side of the equator.  The bands form first at mid-latitude, widen, then move toward the equator as the cycle progresses.  It’s plotted on a “butterfly diagram”, which shows every sunspot since March 1755.  This is what it looks like:

We now know that all conditions on (and in) the Sun effect conditions on Earth; and not just whether or not your cell phone (or you) is going to get fried.  From this site you can link to SOHO (far right) and get a picture of the Sun today, and you can go to SpaceWeather.com, or NASA anytime.

Isn’t it nice to be seeing spots again?

Kitt Peak Observatory, spiral sunspot