Solar Activity Heats Up   
       
   April 14, 2011: If you've ever stood in front of a hot stove, watching a pot   
   of water and waiting impatiently for it to boil, you know what it feels like   
   to be a solar physicist.   
   [...]   
   NASA's Solar Dynamics Observatory recorded this X1.5-class solar flare on   
   March 9, 2011. [movie] Back in 2008, the solar cycle plunged into the deepest   
   minimum in nearly a century. Sunspots all but vanished, solar flares subsided,   
   and the sun was eerily quiet.   
       
   "Ever since, we've been waiting for solar activity to pick up," says Richard   
   Fisher, head of the Heliophysics Division at NASA Headquarters in Washington   
   DC. "It's been three long years."   
       
   Quiet spells on the sun are nothing new. They come along every 11 years or   
   so-it's a natural part of the solar cycle. This particular solar minimum,   
   however, was lasting longer than usual, prompting some researchers to wonder   
   if it would ever end.   
       
   News flash: The pot is starting to boil. "Finally," says Fisher, "we are   
   beginning to see some action."   
       
   As 2011 unfolds, sunspots have returned and they are crackling with activity.   
   On February 15th and again on March 9th, Earth orbiting satellites detected a   
   pair of "X-class" solar flares--the most powerful kind of x-ray flare. The   
   last such eruption occurred back in December 2006.   
       
   Another eruption on March 7th hurled a billion-ton cloud of plasma away from   
   the sun at five million mph (2200 km/s). The rapidly expanding cloud wasn't   
   aimed directly at Earth, but it did deliver a glancing blow to our planet's   
   magnetic field. The off-center impact on March 10th was enough to send   
   Northern Lights spilling over the Canadian border into US states such as   
   Wisconsin, Minnesota, and Michigan.   
   [...]   
   Auroras over Grand Portage, Minnesota, on March 10, 2011. Credit and copyright   
   Travis Novitsky. [more]   
       
   "That was the fastest coronal mass ejection in almost six years," says Angelos   
   Vourlidas of the Naval Research Lab in Washington DC. "It reminds me of a   
   similar series of events back in Nov. 1997 that kicked off Solar Cycle 23, the   
   solar cycle before this one."   
       
   "To me," says Vourlidas, "this marks the beginning of Solar Cycle 24."   
       
   The slow build-up to this moment is more than just "the watched pot failing to   
   boil," says Ron Turner, a space weather analyst at Analytic Services, Inc. "It   
   really has been historically slow."   
       
   There have been 24 numbered solar cycles since researchers started keeping   
   track of them in the mid-18th century. In an article just accepted for   
   publication by the Space Weather Journal, Turner shows that, in all that time,   
   only four cycles have started more slowly than this one. "Three of them were   
   in the Dalton Minimum, a period of depressed solar activity in the early 19th   
   century. The fourth was Cycle #1 itself, around 1755, also a relatively low   
   solar cycle," he says.   
       
   In his study, Turner used sunspots as the key metric of solar activity.   
   Folding in the recent spate of sunspots does not substantially alter his   
   conclusion: "Solar Cycle 24 is a slow starter," he says.   
       
   Better late than never.   
       
   See the ScienceCast of this story on YouTube at: http://www.yout   
   be.com/watch?v=iBl_FOONrB0   
       
       
   Author: Dr. Tony Phillips | Credit: Science@NASA   
       
       
   After years of lying low, sunspot counts are on the rise again. [more] More   
   Information   
       
   The fast CME of March 7, 2011 -- a movie prepared by Karl Battams of the Naval   
   Research Lab in Washington DC   
       
   NASA Heliophysics News   
       
   Space Weather FAQ   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.59   
    * Origin: NCS BBS (1:3828/7)