The Secret Lives of Solar Flares   
       
   Sept. 19, 2011: One hundred and fifty two years ago, a man in England named   
   Richard Carrington discovered solar flares.   
       
   Sunspots sketched by R. Carrington on Sept. 1, 1859. c R. Astronomical   
   Society. [more] It happened at 11:18 AM on the cloudless morning of Thursday,   
   September 1st, 1859. Just as usual on every sunny day, the 33-year-old solar   
   astronomer was busy in his private observatory, projecting an image of the sun   
   onto a screen and sketching what he saw. On that particular morning, he traced   
   the outlines of an enormous group of sunspots. Suddenly, before his eyes, two   
   brilliant beads of white light appeared over the sunspots; they were so bright   
   he could barely stand to look at the screen.   
       
   Carrington cried out, but by the time a witness arrived minutes later, the   
   first solar flare anyone had ever seen was fading away.   
       
   It would not be the last. Since then, astronomers have recorded thousands of   
   strong flares using instruments ranging from the simplest telescopes in   
   backyard observatories to the most complex spectrometers on advanced   
   spacecraft.  Possibly no other phenomenon in astronomy has been studied as   
   much.   
       
   After all that scrutiny, you might suppose that everything about solar flares   
   would be known.  Far from it.  Researchers recently announced that solar   
   flares have been keeping a secret.   
       
   "We've just learned that some flares are many times stronger than previously   
   thought," says University of Colorado physicist Tom Woods who led the research   
   team. "Solar flares were already the biggest explosions in the solar   
   system-and this discovery makes them even bigger."   
       
   http://www.youtube.com/watch?v=0_krMthM_rI   
       
   Click to view a ScienceCast video about the late phase of solar flares.   
   [Youtube]   
       
   NASA's Solar Dynamics Observatory (SDO), launched in February 2010, made the   
   finding:  About 1 in 7 flares experience an "aftershock."  About ninety   
   minutes after the flare dies down, it springs to life again, producing an   
   extra surge of extreme ultraviolet radiation.   
       
   "We call it the `late phase flare,'" says Woods.   "The energy in the late   
   phase can exceed the energy of the primary flare by as much as a factor of   
   four."   
       
   What causes the late phase? Solar flares happen when the magnetic fields of   
   sunspots erupt-a process called "magnetic reconnection."  The late phase is   
   thought to result when some of the sunspot's magnetic loops re-form.  A   
   diagram prepared by team member Rachel Hock of the University of Colorado   
   shows how it works.   
       
   The extra energy from the late phase can have a big effect on Earth.  Extreme   
   ultraviolet wavelengths are particularly good at heating and ionizing Earth's   
   upper atmosphere.  When our planet's atmosphere is heated by extreme UV   
   radiation, it puffs up, accelerating the decay of low-orbiting satellites.   
   Furthermore, the ionizing action of extreme UV can bend radio signals and   
   disrupt the normal operation of GPS.   
       
   SDO was able to make the discovery because of its unique ability to monitor   
   the sun's extreme UV output in high resolution nearly 24 hours a day, 7 days a   
   week.  With that kind of scrutiny, it's tough to keep a secret--even one as   
   old as this.   
       
   The original research of Woods et al may be found in the Oct. 1, 2011, issue   
   of the Astrophysical Journal.   
       
       
   Author: Dr. Tony Phillips | Credit: Science@NASA   
       
   More Information   
       
   Solar Dynamics Observatory -- SDO home page   
       
   More videos and images in support of this story   
       
   SDO's EUV Variability Experiment (EVE) gathered key data that led to the   
   discovery of the late phase   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.64   
    * Origin: NCS BBS (1:3828/7)