From: utzoo!decvax!cca!REM@MIT-MC@sri-unix
Newsgroups: net.space
Title: Gravitational attraction and shifts
Article-I.D.: sri-unix.2385
Posted: Sun Aug  1 18:40:11 1982
Received: Mon Aug  2 03:40:27 1982

From: Robert Elton Maas 
It is my understanding that most supernovas are rather symmetrical.
Since an object that is symmetric has the same gravitational force at
a given distance from its center of mass regardless of the radial
distribution of the mass, providing the distance is greater than the
radius of the object (distance from center to furthest part of its
mass), a supernova would cause no gravitational effect on another
object until after the outer parts of the star that exploded had
passed the other object, by which time that object would be knocked
about by physical impact, masking the change in gravitational force.

An asymmetrical explosion would cause a net change in gravitational
force at distances beyond the radius of the explosion, but computing
just what this change might be as we look at a 2-dimensional telescope
image of the supernova from a distance of many light years, would be
too difficult. We might see the gravitational effect on the other
object and not know whether our observed supernova did it or not
(perhaps a dark star collided with it, perhaps some other
gravitational wave did it, ...). I doubt we can predict the
gravitational change accurately enough to confirm or refute it by our
observations of that other object.