From: Jeff Davis (jdavis@socketscience.com)
Date: Wed Jul 28 1999 - 23:11:54 MDT
Regarding the Gamma Ray Burst as a source of destruction in general and
extinction per this thread in particular:
The latest issue of Scientific American has an article on GRB's (the cover
article in fact), according to which (the latest theory) the bursts are
part of a hypernova explosion of stars larger than 35 solar masses, and are
tightly confined "jets" directed axially outward, north and south, along
the axis of rotation. According to this model, the grb's are detectable by
us only when the distant hypernova is oriented so that the axis of rotation
points more or less directly at the earth. (Presumably in a galaxy so
oriented but safely distant.) Also the total energy released is
substantially smaller when "the signal" we see is the result of axial jets,
than it would be if it were at that same level in all radial directions.
If it should turn out that the axes of rotation of stars in a galaxy are
mostly aligned with the axis of rotation of the galaxy itself, then the
grb jets will mostly be directed out of the plane of the ecliptic into
relatively "empty" space, and only a very few stars radially nearby or
those immediately above or below in the galactic disc will be subject to
obliteration.
Thus, according to this model of grb's, the destruction wrought on the
local galaxy should be substantially less than previously predicted.
Best, Jeff Davis
"Everything's hard till you know how to do it."
Ray Charles
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