And the link of the sun-cycles, with cycle 24 now on the rise.
The last one was abnormally long at 12.6 years, the average over the last two centuries has been 10.7, give or take a fraction, which suggests cycle 24 may be somewhat shorter, but faster in the flux changes between trough and peak, which is about now.
Predictions below
"Even a below-average cycle is capable of producing severe space weather," points out Biesecker. "The great geomagnetic storm of 1859, for instance, occurred during a solar cycle of about the same size we’re predicting for 2013."
The 1859 storm--known as the "Carrington Event" after astronomer Richard Carrington who witnessed the instigating solar flare--electrified transmission cables, set fires in telegraph offices, and produced Northern Lights so bright that people could read newspapers by their red and green glow. A recent report by the National Academy of Sciences found that if a similar storm occurred today, it could cause $1 to 2 trillion in damages to society's high-tech infrastructure and require four to ten years for complete recovery. For comparison, Hurricane Katrina caused "only" $80 to 125 billion in damage.
_http://science.nasa.gov/science-news/science-at-nasa/2009/29may_noaaprediction/
