Listening to the Stars   
       
   Feb. 18, 2016: In 1947, shortly after the end of World War II, a young radio   
   astronomer in Australia named Ruby Payne-Scott was observing the sun when a   
   tremendous roar of static issued from the loudspeaker of her radio telescope.   
   Almost 70 years later, astronomers are still marveling at the outburst.   
       
   "It was so intense," says Gregg Hallinan of the California Institute of   
   Technology it could have been detected from other stars light years from   
   Earth."   
       
   Back in Payne-Scott's day, solar radio bursts were a new thing.  During World   
   War II, engineers had noticed noisy outbursts interfering with radar and radio   
   communications. What could turn the sun into such a powerful natural radio   
   transmitter? Ruby Payne-Scott wanted to find out.   
       
   Hallinan is fascinated by the story of Payne-Scott.  Often the only woman in   
   her physics classes at the University of Sydney, she became a top-secret radar   
   expert during World War II and is widely considered to be one of the finest   
   physicists in Australian history. She was the world's first female radio   
   astronomer, and this was a cutting-edge research problem.   
       
   The sun emits radio bursts almost every day, but many of them are relatively   
   weak. The burst of 1947, however, was a record-setter. No one had ever heard   
   anything like it. Nor did they understand it.   
       
   "Now we believe it was caused by a ferocious CME," explains Hallinan.   
       
   Coronal mass ejections, or CMEs, are billion-ton clouds of plasma that billow   
   away from the sun in the aftermath of magnetic explosions-often, but not   
   always, in tandem with a solar flare. CMEs hitting Earth can spark geomagnetic   
   storms and Northern Lights.  CMEs often announce themselves with a burst of   
   radio waves. The emissions are caused by shock waves in the leading edge of   
   the cloud, which plow through the sun's atmosphere at supersonic velocity.   
       
   Today, NASA has a fleet of satellites in space to observe these explosions on   
   the sun. Scientists work to better understand what causes them so we can   
   protect our satellites from surges of unexpected radiation.  But studying our   
   sun has bigger implications as well - it gives us the insight into the   
   workings of stars all around the galaxy.   
       
   Fast-forward to 2015.   
       
   Deep in the heart of California's Owens Valley, a strange-looking telescope   
   stands in the desert landscape. It is an array of 288 tee-pee shaped wire   
   frames, staring into the sky overhead and harkening back to the days of   
   Payne-Scott. This new radio telescope, called the Long Wavelength Array or LWA   
   is designed to detect the same kind of powerful outburst Payne-Scott recorded   
   in 1947.   
       
   Except... not from the sun.   
       
   "We are looking for CMEs around other stars," explains Hallinan, the   
   instrument's Principal Investigator.   
       
   When the array began normal operations, it began mapping the sky every night   
   listening for shortwave radio bursts from more than 2000 nearby stellar   
   systems.  Although rare, with such a large sample, these radio outbursts could   
   be detectable on a regular basis.   
       
   Hallinan says, "We think we will be able to detect CMEs, especially from the   
   active M-dwarf stars that make up 75% of our sample."   
       
   But CMEs are just the beginning; the array might also find planets.   
       
   When CMEs hit planets in our own solar system, the planets themselves emit   
   low-frequency radio waves as their magnetic fields reverberate from the   
   impact.  The radio emissions come from auroras circling the magnetic poles.   
   Any planet with a magnetic field can produce this kind of "CME echo." The LWA   
   will listen for these echoes, potentially unearthing new worlds in distant   
   star systems.   
       
   After some preliminary observations to test the hardware, the array went into   
   full science mode in late 2015.  Nightly observations will continue for the   
   next two years.   
       
   A discovery by the LWA could ring even louder than Payne-Scott's original   
   burst.   
       
   Stay tuned for updates from science.nasa.gov.   
       
       
   Regards,   
       
   Roger   
      
   --- DB 3.99 + Windows 10   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)