Re: [HCDX]: RE: hard-core-dx V4 #697 bad conditions?

[Alan Gale <alan.gale@xxxxxxxxx>]

At 18:00 01/10/98 -0400, you wrote:

>An article in yesterday's local Tampa paper said that a massive
>eruption on a star, distance 20,000 light-years sent a pulse of energy
>which "illuminated the night time ionosphere as if it were daytime" 
>here on earth....snip.. 

Hi Bob & All,

	I received the following press release from the NASA mailing 
list about this event: 

Date: Tue, 29 Sep 1998 14:10:18 -0400 (EDT)
From: NASANews@xxxxxxxxxxx
Subject: TREMENDOUS GAMMA-RAY FLARE BLASTS EARTH
Sender: owner-press-release@xxxxxxxxxxxxxxxxx
To: undisclosed-recipients:;

Donald Savage
Headquarters, Washington, DC                       Sept. 29, 1998
(Phone:  202/358-1547)

Tim Tyson
Marshall Space Flight Center, Huntsville, AL
(Phone:  256/544-0994)

RELEASE:  98-172

TREMENDOUS GAMMA-RAY FLARE BLASTS EARTH

     An intense wave of gamma rays, emanating from a catastrophic 
magnetic flare on a mysterious star 20,000 light years away, 
struck the Earth's atmosphere on August 27, 1998, providing 
important clues about some of the most unusual stars in the 
Universe.  Scientists said the gamma radiation posed no health 
risk to humans.

       The wave hit the night side of the Earth and ionized (or 
knocked electrons out of) the atoms in the upper atmosphere to a 
level usually seen only during daytime.  This astonishing blast of 
ionization was detected by Prof. Umran Inan of Stanford 
University.  "It is extremely rare for an event occurring outside 
the solar system to have any measurable effect on the Earth," Inan 
said.  It was so powerful that it blasted sensitive detectors to 
maximum or off-scale on at least seven scientific spacecraft in 
Earth orbit and around the solar system.  

       The wave of radiation emanated from a newly discovered type 
of star called a magnetar.  Magnetars are dense balls of super-
heavy matter, no larger than a city but weighing more than the 
Sun.  They have the greatest magnetic field known in the Universe, 
so intense that it powers a steady glow of X-rays from the star's 
surface, often punctuated by brief, intense gamma-ray flashes, and 
occasionally by cataclysmic flares like the one observed on August 
27.  Astronomers think that all these effects are caused by an 
out-of-control magnetic field -- a field capable of heating, 
mixing, and sometimes cracking the star's rigid surface to bits.

       In June a team of scientists led by Dr. Chryssa Kouveliotou 
of NASA's Marshall Space Flight Center in Huntsville, AL, used 
NASA's Compton Gamma Ray Observatory to detect a series of about 
50 flashes from the star, a type called a Soft Gamma Repeater 
(SGR), known as "SGR1900+14" in the constellation Aquila.  During 
the flashing episode, Kouveliotou's team, in collaboration with 
Dr. Tod Strohmayer and his colleagues at NASA's Goddard Space 
Flight Center, Greenbelt, MD, pointed sensitive X-ray detectors 
aboard NASA's Rossi X-ray Timing Explorer satellite toward the 
star.  They found faint X-rays coming from the star, which pulsed 
regularly in intensity every 5.16 seconds.  

     These 5.16-second pulses already had been detected in April, 
when Dr. Kevin Hurley, University of California, Berkeley, aimed 
the Japanese/NASA Advanced Satellite for Cosmology and 
Astrophysics (ASCA) at the star.  Comparisons of the ASCA and RXTE 
data showed that the X-ray pulses were gradually slowing down.

       The finding implies that the Soft Gamma Repeater has a 
magnetic field about 800 trillion times stronger than Earth's 
magnetic field, and about 100 times stronger than any found 
anywhere in the Universe.  Kouveliotou and her team had earlier 
found that another SGR was also a magnetar.  This was exactly what 
Dr. Robert Duncan, University of Texas, Austin, and Dr. 
Christopher Thompson, University of North Carolina, Chapel Hill, 
predicted in 1992 when they originated the "magnetar" theory. 

       Before the NASA team could announce these conclusions, 
SGR1900+14 emitted the tremendous flare of August 27, which was 
observed by almost every spacecraft with a high-energy radiation 
detector in space.  

       "Magnetars seem to answer several mysteries about the 
structure and evolution of stars," said Kouveliotou. "We think 
magnetars spend their first 10,000 years as Soft Gamma Repeaters.  
As they weaken with age and slow their rotation, they become 
Anomalous X-ray Pulsars -- stars that do not have enough 'juice' 
to flash anymore, but which emit a steady flow of X-rays for 
perhaps another 30,000 years.  After that, they fade to black and 
drift for eternity through the heavens.  The absence of observable 
pulsars in some supernova remnants just means that the pulsar's 
lights have gone out sooner than we expected."

       A magnetar forms from the explosion, or supernova, of a 
very large, ordinary star.  The star's heavy center collapses 
under its own gravity into a dense ball of super-compressed matter 
12 miles across.  This "neutron star" consists mostly of neutrons 
in a dense fluid, but the outer layers solidify into a rigid crust 
of atoms about 1 mile deep, with a surface of iron.

       Even with this solid crust, a magnetar is incredibly 
unstable.  Almost unimaginable magnetic fields, about 800 trillion 
times that of Earth's, cause the crust to crack and ripple in 
powerful starquakes.  The energy released in these explosive 
starquakes streams out into space as intense flashes of gamma-
rays.  In the August 27 flare, pure magnetic energy was also 
released, as the star's entire crust was broken to bits.

       "A magnet this strong could erase the magnetic strip on the 
credit cards in your wallet or pull the keys out of your pocket 
from a distance halfway to the Moon," said Duncan. 

                          - end -
EDITOR'S NOTE:  Additional information on magnetars or the Aug. 27 
event is available on the internet at:     
            http://www1.msfc.nasa.gov/NEWSROOM/    
                             and        
               http://www.magnetars.com/

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	"Laugh and the world laughs with you, snore and you sleep alone". 
						
						Mrs. Patrick Campbell
  	===================((((++++++++++++++++++))))===================
  	Alan Gale. 	
  	North-West England. 53:39.3N 2:10.6W		
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