From: g_d_pusch_remove_underscores@xnet.com   
   Copy: garfnodie@hotmail.com   
      
   garfnodie@hotmail.com (David) writes:   
      
   > Hello all, I recently watched a show on Discovery about supermassive   
   > black holes.  Black holes have always fascinated me and this show what   
   > also very interesting.  I have a question though. Black holes   
   > supposedly have such a strong gravitational pull that nothing can   
   > escape them, not even light, so why is it that there are streams of   
   > energy that emanate from the black hole.  How can this energy escape   
   > the gravitational pull of the black hole?   
      
   These so-called "jets," composed mostly of relativistic electrons   
   and positrons, do _not_ "emanate" from the black hole's interior ---   
   they are produced by the "accretion disk" of incredibly hot gas   
   spiraling into the hole. Several plausible mechanisms for generating   
   and accelerating these relativistic jets have been proposed, the two   
   front-runners being electrodynamic acceleration by electromagnetic fields   
   generated via "dynamo" action in the differentially rotating accretion   
   disk, and radiation-pressure acceleration by the intense X-ray and   
   gamma-ray radiation emitted by the incredibly hot accretion disk.   
      
   Other possible acceleration mechanisms exploit the so-called "frame-dragging"   
   effect (AKA the "gravitomagnetic field," a gravitational analog of magnetism)   
   within the "ergosphere" region just outside a rapidly rotating black hole,   
   which can under certain circumstances "slingshot" a fraction of the particles   
   spiraling into the rotating black hole up to a substantial percentage of   
   lightspeed.   
      
      
   -- Gordon D. Pusch   
      
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