Solar Science

A blog of solar physics

Archive for May 2007

NASA: Your guess is as good as ours

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Solar Cycle 24 is late. It should have arrived six months ago, but so far the sunspot cycle has failed to materialize and the Sun is extremely quiet.

So what will Solar Cycle 24 be like when it turns up?

NASA is split on the answer:


Experts Split Over Intensity

The next 11-year cycle of solar storms will most likely start next March and peak in late 2011 or mid-2012 – up to a year later than expected – according to a forecast issued today by NOAA’s Space Environment Center in coordination with an international panel of solar experts.

Expected to start last fall, the delayed onset of Solar Cycle 24 stymied the panel and left them evenly split on whether a weak or strong period of solar storms lies ahead, but neither group predicts a record-breaker. The Space Environment Center led the prediction panel and issued the forecast at its annual Space Weather Workshop in Boulder. NASA sponsored the panel.

“The Space Environment Center’s space weather alerts, warnings, and forecasts are a critical component of NOAA’s seamless stewardship of the Earth’s total environment, from the Sun to the sea,� said retired Vice Adm. Conrad C. Lautenbacher, Ph.D., undersecretary of commerce for oceans and atmosphere and NOAA administrator.

During an active solar period, violent eruptions occur more often on the Sun. Solar flares and vast explosions, known as coronal mass ejections, shoot energetic photons and highly charged matter toward Earth, jolting the planet’s ionosphere and geomagnetic field, potentially affecting power grids, critical military and airline communications, satellites, Global Positioning System signals, and even threatening astronauts with harmful radiation. These same storms illuminate night skies with brilliant sheets of red and green known as auroras, or the northern or southern lights.

Solar cycle intensity is measured in maximum number of sunspots – dark blotches on the Sun that mark areas of heightened magnetic activity. The more sunspots there are, the more likely it is that major solar storms will occur.

In the cycle forecast issued today, half of the panel predicts a moderately strong cycle of 140 sunspots, plus or minus 20, expected to peak in October of 2011. The other half predicts a moderately weak cycle of 90 sunspots, plus or minus 10, peaking in August of 2012. An average solar cycle ranges from 75 to 155 sunspots. The late decline of Cycle 23 has helped shift the panel away from its earlier leaning toward a strong Cycle 24. Now the group is evenly split between strong and weak.

Meanwhile solar cycle 24 appears to be ever later in appearing. Here is the current situation:

This brings us to an interesting situation. After what one astrophysicist communicated to me seemed a lot like numerology in a prediction by NASA, and after statements about the strength of Solar Cycle 24 by the same group, we now have a fence-sitting position (which is always extremely uncomfortable).

The Russian Academy of Sciences annnounced a paper predicting a Dalton-minimum style cooling because of extreme weakness in the predicted strengths of Solar Cycles 24 and 25. It looks like Greenhouse Theory and the Solar Cycle Theory are about to get their sternest tests.

Written by John A

May 20, 2007 at 12:33 pm

Posted in Solar Cycle 24