Re: Interstellar radiation spike

[GACMail98@aol.com]

Subject: Your Question
   Date:  Mon, 5 Oct 1998 11:52:15 -0500 (CDT)
   From:  "Dr. John M. Horack" <horack@uncletupelo.msfc.nasa.gov>
     To:  Glenn

Thanks for the question.  Indeed this is not at the surface, but a measure
of the intensity before interacting in the atmosphere.  So no, the folks
in Hawaii weren't given a "Dental X-ray by the Cosmos." :) Indeed at an
altitude of about 50 km, all the photons had been absorbed by the
atmosphere, and an x-ray detector on the ground would have recorded no
signal whatsoever.

Had the burst been positioned over St. Louis at night, for example, rather
than Hawaii, about the only thing one may have noticed on the ground is
that the long-distance reception of KMOX would have been returned to
daytime levels temporarialy, rather than the 44-state coverage received
during the night, again due to the temporary ionizaiton increase of the
Ionosphere to daytime levels.

Cheers,

John
-======================================================================
Dr. John M. Horack                
NASA/Marshall Space Sciences Laboratory
Office of the Director - ES-01
Huntsville, Alabama USA  35812
john.horack@msfc.nasa.gov         
256-544-1872                      
256-544-9243 (fax)                

Visit http://science.nasa.gov for the latest
information on Science at NASA!!!

---------- Forwarded message ----------
Date: Mon, 5 Oct 98 11:33:08 CDT
From: Mismatched NFS ID's <nobody@xanth.msfc.nasa.gov>
To: john.horack@msfc.nasa.gov

> ----------
> From:         nobody@xanth.msfc.nasa.gov[SMTP:NOBODY@XANTH.MSFC.NASA.GOV]
> Sent:         Monday, October 05, 1998 11:33:08 AM
> To:   john.horack@msfc.nasa.gov
> Auto forwarded by a Rule
> 
Subject: General Space Science

Supposedly-From: Glenn A. Carlson, P.E.
[This message was sent through a www-email gateway.]
--
Regarding the recent burst of x-rays and gamma rays from SGR 1900+14, which is
believed to be a magnetar, according to NASA press releases, the "radiation
reaching Earth had an intensity slightly less than that of a dental X-ray
(Ref: http://science.nasa.gov/newhome/headlines/ast29sep98_2.htm)  

Does this refer to the radiation intensity at the top of the Earth's
atmosphere
or at the Earth's surface?

Thanks.

Glenn A. Carlson, P.E.
St. Peters, MO

~~~~~~~~~~~~~~~~~~
In a message dated 98-10-05 12:44:43 EDT, you write:

<< Forwarded Message: 
 Subj:	 Re[2]: Interstellar radiation spike
 Date:	98-10-05 11:15:49 EDT
 From:	
 To:	GACMail98@aol.com
 
      All the reports I've seen indicate that the "one or two x-ray" 
      magnitude was at the surface of the earth, after atmospheric 
      attenuation.  The effect outside the atmosphere was much greater, 
      shutting down seven satellites and ionizing the upper atmosphere to 
      the same extent that the sun does during the day (I have no idea to 
      what extent that is).
      
      Of course, I've also seen reports that the energy that reached the 
      earth could power civilization for billions of billions of years, 
      which seems a bit far-fetched.  I think a non-technical reporter has 
      mistaken the total energy of the event for the amount of energy 
      reaching the earth.
      
     [sender's name deleted]
 
 
 ______________________________ Reply Separator
_________________________________
 Subject: Re: Interstellar radiation spike
 Author:  GACMail98@aol.com at Internet
 Date:    10/2/98 08:25
 
 
 I understand that the flash was similar in magnitude to a dental x-ray *at
the 
 top of the earth's atmosphere*.  The flash would have been significantly 
 attentuated by the time it reached the surface.
      
 Glenn
 GACMail98@aol.com >>
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