Donald Savage
Headquarters, Washington, DC             December 7, 1994  
(Phone:  202/358-1727)

Steve Roy
Marshall Space Flight Center, Huntsville, AL
(Phone:  205/544-6535)

RELEASE:  94-204

GAMMA RAY FLASHES IN ATMOSPHERE MORE COMMON THAN THOUGHT


     Scientists at NASA's Marshall Space Flight Center in 
Huntsville, AL, are observing rare gamma ray flashes above 
thunderstorms at a rate six times that of previous 
observations. 

     The observations are being made by the Burst and 
Transient Source Experiment aboard NASA's Compton Gamma Ray 
Observatory which was recently modified by ground commands 
to be more sensitive to the events.  

     "The high rate of occurrence of these gamma ray 
events suggests the presence of a little understood, but 
significant phenomena that will have impact in many 
scientific fields," explained Dr. Steve Goodman of 
Marshall's Space Sciences Laboratory. "We're especially 
looking forward to the opportunity to bring together 
investigators from the fields of space and atmospheric 
physics to study these newly discovered events." 

     Scientists previously observed gamma ray flashes 
above thunderstorm activity about once every six weeks. 
Now, they are observing such gamma ray events weekly.  The 
first indications of gamma ray flashes above thunderstorms 
were detected by the Burst and Transient Source Experiment 
earlier this year.

     It is suspected the gamma ray flashes come from a 
rare type of powerful electrical discharge, similar to 
lightning, above large thunderstorm regions.  The observed 
flashes are very brief, lasting only a few thousandths of a 
second.  In the past two months most of the observed gamma 
ray flashes have occurred near the equator, primarily over 
regions of South America and the East Indies known to have 
high thunderstorm activity.

                       -more-
                        -2-

     These recent observations have been confirmed by 
other instruments on the Compton Observatory.  The gamma 
ray observations from the Earth's atmosphere and their 
association with thunderstorms is a complete surprise to 
scientific investigators.  It is suspected the gamma ray 
events may be related to faint, but visible electrical 
discharges observed and reported recently high in the 
stratosphere above thunderstorms. 

     The new observations were presented at a meeting of 
the American Geophysical Union in San Francisco today by 
Dr. Steve Goodman.  The Compton Gamma Ray Observatory is 
managed by NASA's Goddard Space Flight Center in Greenbelt, 
MD, and the Burst and Transient Source Experiment is 
managed by Marshall.  


                         -end-

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