Sunspots Are Still Absent from the Sun

The sun goes through a regular pattern of an 11-year sunspot activity cycle with a cyclical maximum characterized by heightened solar activity and a cyclical minimum characterized by a quiet Sun with no activity. Once that we know of, the Sun went for 50 years without one recorded sunspot. That 50 year period coincided with an lowering of Earth's climatic temperatures between 1650 and 1700.

The Sun is currently on the first up-sweep from solar minimum to solar maximum, so solar activity is expected to gradually increase until the maximum is reached in 2012. Solar activity, referring to sun spots, solar flares and solar eruptions, begins in the higher latitudes and gradually moves to the solar equator during the maximum, then moves away again and finally disappears, leaving a quiet Sun during the two years of the solar minimum.

One of the battalion of satellites that regularly monitors the Sun for daily activity is the Japanese mission called Hinode, which is an Earth-orbiting X-ray telescope that monitors the effect of solar surface activity on the solar atmosphere. In anticipation of the five and a half year climb from solar minimum to solar maximum, the Hinode mission, having the U.S. and U.K. as partners, has built four new ground stations to insure uninterrupted reception of Hinode's signal.

But now, the Sun remains strangely quiet. Recent holographic images showed that the farside of the Sun has been a quiet as the Earthside. Saku Tsuneta, who is the program manager for the Hinode mission, is saying that this quietness is not a great concern.

Since solar physicists can only observe what happens on the Sun, there is no prediction for how long this period of unusual quietness might last. As to causes for the unexpected inactivity, scientists can only say they don't know why it is so.

Of course, opinion is divided among solar physicists as to whether solar minimum is still continuing or whether solar maximum is having a quiet start. A real distinction exists between the two because the Sun's magnetic poles switch around at solar maximum. This means that when the solar cycle changes from minimum to maximum the magnetic fields are halfway through their journey to their switch-around. Since the 2001 solar maximum, solar magnetic north has been at the South Pole. By the next solar maximum in 2012, magnetic north will have returned to the North Pole.

Solar physicists also make no connection between the Sun's activity and Earth's current global climate change problems. Although the previous record of 50 years without solar activity and the coincident small ice age do leave an unpleasant overtone to discussion of the current dead face of the Sun.

Further Reading:

http://www.montana.edu/cpa/news/nwview.php?article=5982&log

http://wattsupwiththat.wordpress.com/2007/02/06/the-sun-has-a-dimmer-switch/

http://environment.newscientist.com/channel/earth/climate-change/mg19325884.500

http://science.nasa.gov/headlines/y2001/ast15feb_1.htm